IMIESA May 2022

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IMESA The official magazine of the Institute of Municipal Engineering of Southern Africa



Disaster Planning & Management How to reduce future flood damage

Providing clean water for future generations Izak Cronje CEO, Tecroveer

AfriSam supplies Raubex in N3 upgrade

Renewable Energy & Electrification Municipal microgrid evolution

Cement & Concrete Low-volume concrete roads I S S N 0 2 5 7 1 9 7 8 Vo l u m e 4 7 N o . 5 • M a y 2 0 2 2 • R 5 5 . 0 0 ( i n c l . VAT )


VOLUME 47 NO. 05 MAY 2022


IMESA The official magazine of the Institute of Municipal Engineering of Southern Africa



Disaster Planning & Management How to reduce future flood damage

Providing clean water for future generations Izak Cronje



Water & Wastewater

Editor’s comment


President’s comment


Index to advertisers

Infrastructure Funding

Cover Story 6

AfriSam supplies Raubex in N3 upgrade

in N3 upgrade

Africa Round-up

Municipal microgrid evolution

I S S N 0 2 5 7 1 9 7 8 Vo l u m e 4 7 N o . 5 • M a y 2 0 2 2 • R 5 5 . 0 0 ( i n c l . VAT )

ON THE COVER A 4 km stretch of one of South Africa’s most vital highways, the N3, is receiving an extensive upgrade by Raubex Construction. P6

INDUSTRY INSIGHT Setting the standard for Blue and Green Drop certification compliance, Tecroveer has led the market with integrated turnkey solutions, backed by patented processes and technologies, for close to five decades. IMIESA talks to Izak Cronje, CEO of Tecroveer, about their expertise in water and wastewater optimisation. P10



Industry Insight Cement & Concrete Low-volume concrete roads


Providing clean water for future generations

Strategy to improve water infrastructure for municipalities


Roads & Bridges | Asphalt Plants

Infrastructure news from around the continent Renewable Energy & Electrification



CEO, Tecroveer

AfriSam supplies Raubex

Water-Check programme sets the benchmark

Linnhoff plant overcomes logistical challenges on Tema road project


Environmental Engineering 10

Disaster Planning & Management

The vital role of retaining wall structures


Sand & Aggregates

How the disaster declaration supports local municipalities


How to reduce future flood damage


Renewable Energy & Electrification

Resource management key for future growth


Investment 40

Optimising energy supply and demand


Home of the Brick

Municipal microgrids promote clean energy and autonomy


Who’s Who in Cement & Concrete

Working towards EPC compliance


Correct cabling specification key for PV installations

Precast manholes offer value and durability



The new and definitive Terraforce Design Guide


Consider low-volume concrete roads for extreme weather conditions


Perfecting the art of dam wall rehabilitation


Information & Communications Technology Construction in the cloud


Digital twin solution for AEC practitioners 25

Water & Wastewater

Flooring refurbishment at the SAAO


Measuring in a cloud of dust


A study: water security and climate change risks for municipalities


Vehicles & Equipment

Solutions to bring water to our people


Summary: National Green Drop Report


Walk-behind roller upgrade sets new standard


Maintaining the highest drinking water standards


Advantages of reduced-temperature asphalt







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EDITOR’S COMMENT MANAGING EDITOR Alastair Currie SENIOR JOURNALIST Kirsten Kelly JOURNALIST Nombulelo Manyana FEATURES WRITER Ziyanda Majodina HEAD OF DESIGN Beren Bauermeister DESIGNER Lizette Jonker CHIEF SUB-EDITOR Tristan Snijders CONTRIBUTORS James Cullis, Andries Fourie, Bruce Munnings, Shireen Sayed, Bhavna Soni, Martin Stols, Peter Townshend PRODUCTION & CLIENT LIAISON MANAGER Antois-Leigh Nepgen PRODUCTION COORDINATOR Jacqueline Modise GROUP SALES MANAGER Chilomia Van Wijk BOOKKEEPER Tonya Hebenton DISTRIBUTION MANAGER Nomsa Masina DISTRIBUTION COORDINATOR Asha Pursotham SUBSCRIPTIONS PRINTERS Novus Print Montague Gardens ___________________________________________________ ADVERTISING SALES KEY ACCOUNT MANAGER Joanne Lawrie Tel: +27 (0)11 233 2600 / +27 (0)82 346 5338 Email: ___________________________________________________

PUBLISHER Jacques Breytenbach 3S Media Production Park, 83 Heidelberg Road, City Deep Johannesburg South, 2136 PO Box 92026, Norwood 2117 Tel: +27 (0)11 233 2600 ANNUAL SUBSCRIPTION: R600.00 (INCL VAT) ISSN 0257 1978 IMIESA, Inst.MUNIC. ENG. S. AFR. © Copyright 2022. All rights reserved. ___________________________________________________ IMESA CONTACTS HEAD OFFICE: Manager: Ingrid Botton P.O. Box 2190, Westville, 3630 Tel: +27 (0)31 266 3263 Email: Website: BORDER Secretary: Celeste Vosloo Tel: +27 (0)43 705 2433 Email: EASTERN CAPE Secretary: Susan Canestra Tel: +27 (0)41 585 4142 ext. 7 Email: KWAZULU-NATAL Secretary: Narisha Sogan Tel: +27 (0)31 266 3263 Email: NORTHERN PROVINCES Secretary: Ollah Mthembu Tel: +27 (0)82 823 7104 Email: SOUTHERN CAPE KAROO Secretary: Henrietta Olivier Tel: +27 (0)79 390 7536 Email: WESTERN CAPE Secretary: Michelle Ackerman Tel: +27 (0)21 444 7114 Email: FREE STATE & NORTHERN CAPE Secretary: Wilma Van Der Walt Tel: +27 (0)83 457 4362 Email: All material herein IMIESA is copyright protected and may not be reproduced without the prior written permission of the publisher. The views of the authors do not necessarily reflect those of the Institute of Municipal Engineering of Southern Africa or the publishers. _____________________________________________

Mentorship, collaboration and teamwork win the day


e live in a world of constant change and uncertainty. This has been the case throughout the path of human existence and our planet’s evolving history. But it’s how we respond to the changes we experience that defines our future. Nothing is insurmountable; however, we first need to take collective responsibility for the things we can control, like getting South Africa’s freight and passenger rail services back on track, fixing Eskom, and ensuring that our water and wastewater treatment plants are fully compliant. We have the skills and we certainly have the agricultural, construction, manufacturing and mining resources. But we still haven’t connected the missing dots in terms of full trust and collaboration between the public and private sector. One of the major frustrations expressed by the business community is that, despite assurances from the public sector, bureaucratic hurdles are not being removed fast enough. Initiatives like government’s Operation Vulindlela are meant to introduce urgent structural reforms. Areas include digital communications, electricity, water and transportation, where there’s a varying degree of progress against targets. A prime example is the conclusion of South Africa’s first radiofrequency spectrum auction in March 2022, which was hosted by the Independent Communications Authority of South Africa. More than R14.4 billion was raised for the fiscus, and the expectation is that this will spur a digital transformation that makes the internet available to even the poorest households.

Responding to global economic turbulence Moving forward, an even greater priority is the need to respond to the highly volatile financial market conditions induced by the Russia-Ukraine conflict. The collective views shared by experts at the World Economic Forum’s annual meeting in Davos,

Switzerland, in May 2022 show that there’s a rocky road ahead for most nations – and especially developing economies. Key issues include potential global food shortages, hyperinflation, and a steep rise in energy prices in the short term. According to Statistics South Africa, local fuel prices rose by around 33.2% in the 12 months to March 2022. Within the mix, the price for petrol and diesel increased by around 32.6% and 35.1%, respectively, and more hikes are on the way during 2022. This obviously places renewed pressure on household budgets and makes the cost of doing business far greater. None of these experiences are new. For instance, while it had severe consequences at the time, the 1970s Energy Crisis was not the beginning of the end, but a major shift induced by a series of geopolitical events like the one we’re witnessing in Ukraine. It also spurred the shift to renewable and alternative energy solutions, and e-mobility, all of which are rapidly gaining momentum today. Those countries that successfully weather the peaks and troughs do so because they’re more resilient and internationally competitive. That is largely due to building high-performing economies and forging the best international trading alliances. It’s all about the right enabling framework. A case in point is the participative management style unfolding within our local coalition governments, particularly within South Africa’s major metros. Healthy debate here is already yielding more balanced and beneficial results on the infrastructure front.

Alastair To our avid readers, check out what we are talking about on our website, Facebook page or follow us on Twitter and have your say.



Infrastructure News

The official magazine of the Institute of Municipal Engineering of Southern Africa


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Disaster Planning & Management How to reduce future flood damage

Providing clean water for future generations Izak Cronje CEO, Tecroveer

supplies Raubex in N3 upgrade

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Renewable Energy & Electrification Municipal microgrid evolution

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IMIESA May 2022


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Ecology and infrastructure

NEED TO BE IN BALANCE Within South Africa’s recent flood-ravaged zones, the work of rebuilding has begun. It’s a mammoth task and our thanks go out to all the municipal engineering and allied personnel nationwide who are tirelessly working to restore damaged pipeline, transpor tation and power distribution networks, alongside other affected infrastructure.


he aftermath of the storms within eThekwini alone has meant that some residents have had to experience weeks without electricity or working water connections. In addition, thousands of displaced persons are currently housed in temporary shelters. The lessons learnt will certainly help to shape future disaster management planning, and flood minimisation. Bhavna Soni, president, IMESA

Man-made disasters There are some who argue that climate change is a natural occurrence, but the scientific evidence shows conclusively that industrialisation, urbanisation and an ongoing global population explosion have contributed to a significant rise in global warming. To underscore the point, the UN states, “Three-quarters of the land-based environment and about 66% of the marine environment have been significantly altered by human actions.” These and other pressing issues are the motivation behind the UN’s International Day for Biological Diversity, held on 22 May 2022, with the theme ‘Building a shared future for all life’. The core message is that there’s an urgent need to restore and protect endangered ecosystems, such as lakes, rivers, forests, agricultural zones, wetlands and catchments. These ecological systems sustain us; their healthy existence is crucial for our future water security and the prevention of soil erosion that contributes towards land degradation.

Pollution One of the most appalling examples of environmental pollution were the tonnes of river-borne plastic waste that ended up on

Durban’s beaches during the April 2022 storms. Plastic and other flotsam also clogged rivers, weirs and stormwater systems, and exacerbated the floods. This plastic finds its way into our habitats due to illegal dumping and irresponsible littering, compounded by poor waste management within both formal and informal settlements. However, as with every scenario, there’s an upside where waste collection and the recycling of plastic products becomes a job creator, and a catalyst of the circular economy. The latter is a major driver in reversing biodiversity losses and lowering greenhouse gas emissions, and we must strive collectively as a society to ensure safe disposal or reuse.

Annual Conference on track Environmental stewardship and sustainable urban design will be among the key themes at the upcoming 85th IMESA Annual Conference in Gauteng, being held between 2 and 4 November 2022. (For further details on exhibitor, delegate and sponsorship opportunities, visit We’re pleased to confirm that we received 41 abstract submissions in the first round

of selecting the final list of confirmed speakers. These abstracts have now been evaluated in terms of criteria that include innovation, thought leadership, business value, interest and conformance to the conference theme, which is ‘Adapting to our Changing World’. We really appreciate the interest and support from all those who submitted abstracts. Across the board, they reflect the depth, experience and expertise of South Africa’s multidisciplinary infrastructure implementation teams, ranging from engineering, construction and project management, to finance, law and public administration.

Cutting the red tape Well before the Covid-19 lockdowns, the issues that impeded infrastructure implementation were hot topics of debate at our IMESA conferences. This has become an even more burning issue in 2022 as South Africa attempts to rebound from the Covid-19 socioeconomic impacts, the July 2021 unrest in Gauteng and KwaZulu-Natal, and now billions in infrastructure flood damage. At this year’s conference, there will be a concerted focus on ways to clear the procurement and funding bottlenecks, with the participation of key implementation stakeholders that include National Treasury and the South African Local Government Association. Immediate and renewed social infrastructure investment within municipalities is essential for South Africa’s economic recovery. It’s also vital for protecting and preserving our ecological infrastructure.

IMIESA May 2022


INDUSTRY INSIGHT AfriSam is supplying readymix concrete from its Umlaas Road operation, with its Pietermaritzburg facilities as a backup


in N3 upgrade

As part of extensive upgrades to one of South Africa’s most vital highways, JSE-listed contractor Raubex Construction is being supplied with construction material by AfriSam, including cement, readymix, aggregate and other quarry material.


aubex has been working on a 4 km stretch of the N3 highway, between Dardanelles and Lynnfield Park since January 2021, which will expand the current two-lane road to four lanes in each direction. The N3 between the port city of Durban and the country’s powerhouse of Johannesburg carries heavy traffic volumes that have only increased in recent decades. This project is part of government’s key Strategic Integrated Project focusing on the Durban-Free StateGauteng logistics and industrial corridor. It will improve access to Durban’s export and import facilities, and raise efficiency along this route. According to Abri Lubbe, contracts manager, Raubex, the road contract includes the widening

of four existing bridges and the construction of an entirely new road-over-road bridge structure at the Umlaas Road junction. This new twin-spine bridge over the R603 will allow easier access for both north- and south-bound N3 traffic heading for Richmond.


“Work on widening the bridges at the Umlaas and Sunnyvale underpasses has been completed, as has the agricultural underpass,” says Lubbe. “This involved the construction of abutments, the application of precast beams, in situ decks, balustrades and end-blocks.” There is also one road-over-rail bridge that will be extended once the contraflow stage is reached, where traffic is diverted on to one side of the highway to give contractors full access to the other side. Piling for the twinspine bridge The project includes the widening of four existing bridges and the has been construction of an entirely new road-over-road bridge structure


IMIESA May 2022

completed, allowing the foundations to progress on this lengthy aspect of the project; work began on this three-span structure in October 2021 and is due for completion by the end of 2023. Thys Greeff, construction manager, Raubex, explains that the contraflow will allow roadwork on the south-bound lanes to begin in earnest, which will include the complete revamp of the existing lanes.

Road construction “We are excavating the existing road by between 1 000 mm and 600 mm, and will fill this with blasted material from AfriSam,” says Greeff. “Depending on conditions, the next level may then comprise a 150 mm capping layer and a 300 mm G6 selected layer. This is followed by a 350 mm stabilised sub-base layer of crushed material.” AfriSam is providing its specialised roadstabilising cement, Roadstab Cement, which is being supplied in 50 kg bags to the Raubex subcontractor who spreads the cement on to the sub-base layer. By the end of the contract, around 180 000 bags will have been supplied, making up some 9 000 t of cement. The road layer will be completed with a 200 mm asphalt layer, comprising a 120 mm EME base, a 40 mm AP-1 interlayer, and a 40 mm bitumen-rubber gap-graded wearing course, says Greeff.


To date, the ramp from the N3 on to the P338 road heading west towards Thornville has also been completed, with just the asphalt layer being finalised. The project is currently busy with three other ramps and two temporary ramps and cross-overs to accommodate traffic. Adding another two lanes – and sometimes three – on each side of the highway has meant taking up the central reservation that has always existed between the north- and south-bound highways. In its place will be a concrete median barrier, mostly of precast concrete units. “In addition to the precast barriers, there will also be sections of the median barrier that will require readymix to be poured in situ,” says Lubbe. “This will be done where the road is in a superelevation, or where the camber points – or pivot points – differ on the north- and southbound roads.”

AfriSam is providing around 180 000 bags of its Roadstab Cement for road stabilisation

the project peaks. With regard to the readymix supply, AfriSam has already begun stockpiling the 20 mm aggregate and river sand.

Hands on deck

According to Randal Chetty, regional sales manager, AfriSam, the readymix supply will come from AfriSam’s plant at Umlaas Road – conveniently located as part of the company’s extensive national footprint. To date, over 300 000 tonnes of construction material – including unselected fill, blasted G6 material and 20 mm aggregate – has been supplied. “We also have a quarry at our Pietermaritzburg facilities, which will provide us with backup supply if there is a need,” says Chetty. The scale of the various upgrading projects on the N3 in this region is putting considerable pressure on the capacity of suppliers in the area, says Lubbe. There are currently three overarching road upgrade projects under way between Cato Ridge and Ashburton.

The project is demanding considerable human resources – from Raubex’s on-site team to its subcontractors and local workforce. Lubbe notes that there will be 300 to 350 personnel on-site by the time the project peaks, around August to October this year. The majority of those are workers from the local area, in whom Raubex has invested significantly in skills, safety and other training. Greeff highlights the range of equipment being deployed to keep the work streamlined and efficient. This includes four graders, each served by two compacting rollers and 42 tipper trucks with loading capacity of 10 m3 each. A Cat reclaimer is at work on the sub-base, and a specially engineered barrier truck moves the weighty 6 m temporary concrete barriers to control traffic flow. Water bowsers assist with dust suppression and dampening the road layers, and a fixed asphalt plant has been installed near the quarry at Umlaas Road. The roadwork on this project is likely to be completed by mid-2024, with some of the ramps and other infrastructure possibly taking until early 2025.


Contactless system

On the readymix side, AfriSam’s plant at Umlaas Road will be supplied with aggregate material from the quarry that shares this location. “Planning ahead for the eventuality that aggregate must be sourced from both quarries, we have concrete mix designs for Umlaas Road and for Pietermaritzburg material,” says Chetty. “These have been accepted by the engineers, the contractor and subcontractors.” He highlights that planning is critical in large projects like this one, to ensure adequate and timeous supply of both blue and brown material to where it is needed on the roadside. This includes understanding the timeframes and planning for

Lubbe emphasises that the tender process for local subcontractors – in terms of the

Supply line

company’s contract participation goals – is highly structured. This is to ensure a fair bidding process that empowers suppliers and service providers in the local area. However, the Covid19 pandemic, along with its restrictions on movement and meetings, presented a severe challenge to Raubex’s advertising of tenders to meet its contract participation goals. This was met by an innovative and unique solution – perhaps the first of its kind in the local construction sector. “To ensure compliance and social distancing, we were able to develop a transparent and contactless system,” he says. “Subcontractors would receive a link from us on their mobile phone or computer, and would go online to find all the details on that section of work.” They could then upload all their necessary documentation to tender their bid – avoiding the paper process and all the usual logistics that would require hard copies to change hands. So successful has the system been that the company is likely to use it well after Covid-19 restrictions have ended.

Sections of the median barrier require readymix to be poured in situ

IMIESA May 2022




GHANA Primary substation increases power capacity A new substation at Sefwi Bibiani in the Western Nor th Region of Ghana will improve power supply to 36 towns in the Bibiani District region. This substation was recently inaugurated by the Electricity Company of Ghana (ECG). It has a capacity of 2 x 20/26 MVA, valued at about US$8.7 million (R138.5 million). Before the construction of the primar y substation, the Bibiani District region had a booster station, which supplied electricity to residents. However, with the ever-increasing electricity demand due to industrialisation, especially following the government of Ghana’s One District One Factor y agenda, ECG is compelled to provide reliable power supply to suppor t the demand. ECG’s 2022 approved budget for projects to improve ser vice deliver y in the Western and Western Nor th regions totals about GH₵ 24.7 million (R51.5 million). These projects include the construction of Elubo Bulk Supply Point, construction of 2 x 20 MVA Primar y station, reconstruction of Axim Switching Station, and the reconstruction of Sefwi Dwenase Primar y Substation.

EGYPT Step towards green hydrogen production

ANGOLA Megaproject to house 20 000 people Community and housing project Centralidade do Halavala, located in the municipality of Bailundo, Huambo Province, was recently inaugurated in the presence of His Excellency, the President of Angola, João Lourenço. The project’s aim is to build urban communities, as envisioned by the Angolan government within the scope of the National Urbanism and Housing Program, and implemented together with contractor Kora, the real-estate and urbanism subsidiar y of the Mitrelli Group. In addition to the provision of more than 3 000 housing units, it was designed to provide a new way of life to more than 20 000 inhabitants who will have greater access to essential ser vices such as education, health, security and a network of internal and external infrastructures open to the community. The new residents will be accompanied by social ser vices throughout, provided by the Multisectoral Integration Program initiative, to ease the cultural transition into their new homes and community, resulting in a better quality of life for them and a brighter future for their families.


IMIESA May 2022

UAE’s Masdar and Egypt’s Hassan Allam Utilities have signed agreements with state-backed Egyptian organisations that will see the par ties work together on the development of large-scale green hydrogen projects in the Suez Canal Economic Zone and on the Mediterranean coast. “In the first phase of the project, Hassan Allam Utilities and Masdar aim to establish a green hydrogen manufacturing facility, which would be operational by 2026, producing 100 000 t of e-methanol annually for bunkering in the Suez Canal. The electrolyser facilities in the Suez Canal Economic Zone and on the Mediterranean could be extended to up to 4 GW by 2030

to produce 2.3 Mt of green ammonia for expor t, as well as supply green hydrogen for local industries,” explains Amr Allam, CEO of Hassan Allam Holding. He adds that Masdar and Hassan Allam Utilities see Egypt as a hub for green hydrogen production, targeting the bunkering market, expor t to Europe, and boosting local industr y. “Egypt enjoys abundant solar and wind resources that allow generation of renewable power at a highly competitive cost – a key enabler for green hydrogen production. Egypt is also located within close proximity to markets where demand for green hydrogen is expected to grow the most, providing robust opportunity for export.”


KENYA Improved access to clean affordable energy In Kenya, renewable energy currently accounts for 73% of installed power generation capacity, while 90% of electricity used in the East African countr y is generated by green energy sources such as geothermal, wind, solar and hydroelectric. According to the Energy Principal Secretar y, Major General Dr Gordon Kihalangwa, Kenya is on course to achieve a 100% use of clean energy by 2030 and to achieve 100% access to clean cooking by 2028. Kenya’s flagship installation, the Lake Turkana Wind Power (LTWP) Project, is the largest public-private investment in the countr y’s histor y at a cost of €625 million (R10.5 billion), and is the biggest wind power plant in sub-Saharan Africa. Comprising 365 wind turbines, each with a capacity of 850 kW and a high-voltage substation, LTWP supplies renewable energy to the Kenyan national grid, and is committed to the sustainable application of all resources to the benefit of the environment. The electricity generated by LTWP has reduced Kenya’s reliance on fuel impor ts from neighbouring countries, saving more than €281 million (R4.7 billion) between 2018 and 2021, and enabled the continued economic growth of the countr y in the process. The Principal Secretar y says reforms in the energy sector are continuously being formulated and implemented to improve the sustainability of the per formance of the national economy and reduce greenhouse gas emissions. These reforms will suppor t the implementation of the Paris Agreement and effor ts towards achieving Kenya’s climate targets as set out in the countr y’s first Nationally Determined Contributions.

MOZAMBIQUE Port of Maputo unveils rehabilitated berths A total of 1 058 m of ber thing area (composed by ber ths 6, 7, 8 and 9) was recently inaugurated by the President of Mozambique, Filipe Jacinto Nyusi. The ber ths – rehabilitated, expanded and dredged to depths of up to -16 m – are now fully operational and will allow the por t of receive and load an increasing number of bigger vessels. In an inaugural speech, President Nyusi said, “With this increase, there will be more revenue and income for Mozambicans.” Some of the planned investments for the por t include: • creation of a food terminal (grains, sugar, vegetable oils, molasses) • expansion of the container terminal • expansion of the intermodal container terminal • expanding TCM (dr y bulk) capacity to 12 million tonnes per annum.

IMIESA May 2022


The Karee wastewater treatment plant

PROVIDING CLEAN WATER for future generations

Setting the standard for Blue and Green Drop certification compliance, Tecroveer has led the market with integrated turnkey solutions, backed by patented processes and technologies, for close to five decades. IMIESA talks to Izak Cronje, CEO of Tecroveer, about their expertise in water and wastewater optimisation.


hen the South African government’s National Water and Sanitation Masterplan (Volume 1: Call to Action, Version 10) was released in 2018, statistics quoted indicated that some 56% of wastewater treatment works and 44% of water treatment works were in a poor or critical condition. Plus, 11% were dysfunctional. Fast-forward to 2022 and the situation remains dire, with ongoing interventions required within the municipal arena, as well as private industry, to protect South Africa’s water quality and water security. “However, with an innovative approach, the upside is that most if not all treatment works can be brought back to compliance standards.

Plus, it’s clearly cheaper to reinstate than replace,” points out Cronje, adding that one of Tecroveer’s core specialisations is the turnkey refurbishment and upgrading of municipal water and wastewater treatment plants, optimising the use of existing infrastructure by incorporating innovative technologies. In many cases, these are also operated and maintained by Tecroveer. “On all sites where we’re called in to do a condition assessment of the current plant health, we conduct an in-depth analysis and submit a detailed report, which includes a comprehensive budget to meet immediate and future priorities,” he explains. “As with all our projects, proposals are fit for purpose and, wherever practical, we integrate the existing

Izak Cronje, CEO, Tecroveer


Tecroveer’s patented Transfer Mixer technology revolutionises process performance by combining mixing and high-volume, low-pressure pumping

infrastructure and equipment into our design to save on capex and opex costs. Essentially, we don’t only repair existing equipment, but do an in-depth investigation to diagnose the problem and address any process and/or equipment shortcomings.” Tecroveer’s competitive advantage is the group’s turnkey design and contracting approach, with vastly experienced process, civil, electrical and mechanical engineers employed in-house. Plant designs are supported by ongoing research and development, and Tecroveer’s comprehensive range of mechanical and electrical equipment, which is manufactured, sourced and supported in South Africa. “The starting point for optimum plant performance is predictive and preventative maintenance. Since many municipalities are financially constrained, it makes sense for them to outsource operations and maintenance to skilled contractors who provide performance guarantees and incur the cost of any budget overruns,” Cronje continues. Within the private sector, there’s also been a growing trend to outsource non-core functions, with Tecroveer providing design-buildoperate-maintain effluent treatment services for industrial clients that include AB InBev and Distell.

Process excellence at Marikana Historically, the mining sector has always been a key focus area for Tecroveer – a prime example being its long-term operations contracts for Lonmin’s, and subsequently, Sibanye-Stillwater’s numerous wastewater treatment plants at the Marikana PMG mining

complex in the North West. (Sibanye-Stillwater acquired the Marikana shafts as part of the Lonmin acquisition in June 2019.) Some 15 years ago, Tecroveer was invited to submit a design and build proposal for a new 4.5 Mℓ/day facility alongside an existing Tecroveer plant originally commissioned in the 1980s at Lonmin’s Karee operation. This new plant would support the mine’s need for additional water beyond its capped Rand Water allocation. The new wastewater plant would also serve the requirements of the surrounding Marikana community, which at that stage didn’t have a waterborne sanitation system. Given the go-ahead, Tecroveer proceeded with its design and subsequent commissioning of the new Karee plant. As part of the contract, Tecroveer also upgraded an existing pump station, with the local municipality installing the pipeline connections to the new treatment works. Additionally, Tecroveer designed a stormwater catchment network at Karee to capture run-off from the mine’s contaminated areas and channel it through to the effluent storage dams to increase the amount of water that could be reused. “Although the mine’s initial plan included the upgrading of the old works, the Tecroveer plant at Karee has performed so optimally that this hasn’t been necessary,” says Cronje. “Aside from the process efficiencies, another contributing factor is that our plant designs are conservative and can actually handle much higher loads when needed.”

Wonderkop The success of this project led to Tecroveer being awarded the turnkey contract for the design and operation of a new 9 Mℓ/day plant for Lonmin at its Wonderkop site within the

Marikana complex. Commissioned in 2010, Wonderkop provides the dual benefit of treating the mine’s wastewater as well as sewage effluent from the local community. This single Tecroveer plant was built to replace five redundant treatment works within the Wonderkop area. It currently treats around 6 Mℓ/day, with clean water recycled back to the mine’s reuse dams for downstream industrial and irrigation applications. All operations are fully automated, monitored and controlled via Scada systems.

Unique technologies Common across its designs, Wonderkop and Karee have standby systems that enable around 50% of the plant to continue operating during maintenance interventions. Generators provide backup power in the event of load-shedding. A distinctive feature on these plants is that Tecroveer’s treatment processes employ biological reactors that operate without internal pumps. Internal transfer is performed by Tecroveer’s patented Transfer Mixer technology. “The Tecroveer Transfer Mixer has been applied on more than 20 project sites since 2002, and revolutionises process performance by combining mixing and high-volume, low-pressure pumping. The advantages include the elimination of pumps for recycle flows, lower power consumption, a non-clog design, higher return rates, as well as improved process performance resulting from the low-speed, non-shear and anoxic pumping,” Cronje explains. The plug-flow design of Tecroveer’s vertical aerators allows for the control of the anoxic and aerobic zone through variable-speed

Final treated effluent at Wonderkop. The employment of a suction lift clarifier is a characteristic Tecroveer design element

IMIESA May 2022


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drives. Aeration is proportional to organic loading into the plant, further improving overall energy efficiency. In turn, Tecroveer’s patented Petro process is designed to reduce the energy and reactor volume requirements of the activated sludge system. These systems, in combination, ensure stringent effluent discharge standards.

Sludge Handling the resulting sludge by-product is then the final phase in the process, with Wonderkop serving as the central facility for all the mine’s treatment plants. “The composting methods employed, with or without bulking agents, have a number of potential beneficial applications,” says Cronje. Waste-activated sludge is dewatered using Tecroveer’s Multi-disc screw press for dewatering and then mixed with garden waste to produce compost. The reliability and operational cost-effectiveness are far superior to conventional dewatering technologies, as the equipment has no wearing/tearing belts and moving parts. This final product is then used by the mine to promote vegetation growth during the rehabilitation of its tailing dams.

The 9 Mℓ/day Wonderkop wastewater treatment plant, commissioned in 2010 and still in pristine condition

Package plants Alongside Sibanye-Stillwater’s large-scale treatment works is a Becon Watertech package plant (with a capacity of 30-100 kℓ/day) installed at the mining group’s nearby game farm, which also serves as a conference and training centre. A sister company to Tecroveer, Becon Watertech’s Be-Pac range (from around 15-500 kℓ) is locally produced and meets smaller-scale wastewater treatment requirements for a wide spectrum of users – from schools to housing developments. A notable feature of these units, which are modular and scalable, is their Rotating Biological Contactor (RBC) filter system, based on a proven technology developed in Germany in the late 1800s. These RBC units need minimal operational input and control, with a single gearbox driving the rotor. “In the past 12 years, we’ve achieved close to a 99% compliance record for all eight treatment plants previously owned by Lonmin and now forming part of Sibanye-Stillwater’s Marikana operations,” says Cronje. “And, during this period, there have been no additions or changes to the original Tecroveer processes, and no downtime, which underscores the success of our design methodology. “We’re especially proud of our Green Drop and Blue Drop performance across every site

A Tecroveer Becon Watertech package plant

The final stage of the sludge dewatering process at Wonderkop. Tecroveer specified a multidisk screw press dewatering system

where we operate in South Africa and our role in delivering the highest process standards for our private and public sector clients,” adds Cronje. “Given the right technology and experience, close to 100% compliance is definitely achievable,” Cronje concludes.

IMIESA May 2022


The KZN floods have been a devastating reminder that disaster planning and management is the business of everyone in a municipality (Credit: KwaZulu-Natal Provincial Government)

How the disaster declaration

SUPPORTS LOCAL MUNICIPALITIES disaster has placed local food security at risk.

The National State of Disaster declared by government following the floods in KwaZulu-Natal is an opportunity for disaster management officials to leverage all levels of the state’s emergency capacity. There is also an important contribution to be made by the private sector in supporting government efforts by providing engineering, environmental and disaster risk reduction expertise. By Andries Fourie & Martin Stols


he scale of the recent KwaZuluNatal (KZN) floods and their consequences led to the announcement of a National – rather than municipal or provincial – State of Disaster in terms of Section 27 of the Disaster Management Act (No. 57 of 2002). For those municipalities affected, the declaration gives them access to not only local resources and contingencies, but to assistance from provincial and national departments. Local municipalities are supposed to have a Disaster Management Fund, but where this is insufficient – as is now clearly the case due to the scale and extent – they


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Rapid response

Andries Fourie, senior technologist: Disaster & Risk Management, SRK Consulting

Martin Stols, principal consultant, SRK Consulting

can draw resources from national and even international sources. This gives access to services that are often quite specialised, such as search-and-rescue teams. In this instance, the South African National Defence Force (SANDF) was deployed – and was expected to bring in expertise to assist with the immediate disaster response and recovery. There should even be capacity in the SANDF to build temporary bridges where structures have been washed away to ensure communities have physical access to services and markets. Opening up international channels of support could also contribute food assistance where the

A central concern in all disaster response plans is to return the affected areas and people to some form of normality as quickly as possible. There are particular issues that need rapid and effective responses, such as the provision of water and sanitation services. This is to avoid the potential knock-on effects of secondary impacts – like waterborne diseases – which prolong the recovery period. This makes close collaboration a vital element of success in any municipality’s disaster response. While the disaster management team at municipal level is expected to play an important coordinating role, it obviously does not actually repair roads, electricity cables or water pipes. It relies on the various operational units to fulfil these tasks – which are made more difficult by the disaster conditions. It should also be remembered that a disaster declaration comes with certain time-related constraints. Funds made available for the immediate phase following a disaster need to be spent within 60 days. This is separate from the longer-term recovery grant, which can be utilised over a longer period.

Mobilising funds Being an emergency situation, a quick response is invariably going to be more effective than a delayed one, provided that the action is appropriate and well planned. However, it is often difficult to mobilise funding rapidly if the processes in place are too onerous or bureaucratic. For instance, a normal tender process with its necessary checks and balances may take too long in the case of an emergency. At the same time,


government is committed to ensuring that all public spending is responsible and achieves value-for-money results. The context in which the KZN flood disaster has occurred is one where municipal resources are already stretched. In many areas, basic services were under strain even before the floods occurred. This of course makes it even more difficult for the disaster management response to be quickly and effectively mobilised. There is, however, a valuable pool of relevant experience and specialised knowledge among private sector consulting engineers and scientists municipalities can draw on for support. By planning in advance with the most appropriate experts, the disaster response can be rolled out more quickly. One government department has already been exploring the modalities of standing agreements with relevant experts, so that the appropriate skills can be mobilised through an emergency procurement process. The guidelines would provide for a panel of experts representing a range of well-respected players, which the department can draw on at short notice. This approach is very useful in addressing disaster situations, where it is clear that in-house resources will not be sufficient to meet the sudden need.

Monitoring At the same time, state expenditure in a time of disaster must still be closely monitored in terms of its impact. Already, government makes extensive use of consulting engineers and scientists to ensure that disasterrelated funding is well spent. For instance, municipalities and other levels of government often assign specialised professionals from consulting firms to help assess damage – and to estimate the reasonable cost of repair or rebuilding. Qualified professionals also help government to track the expenditure once a project is awarded. This is important in making sure that spending is in line with general policies and the specific demands of the contract. The monitoring also ensures that the average citizen can once again receive vital services from rebuilt clinics, schools, hospitals and other public institutions.

The aftermath of the storm caused major disruptions to transportation services (Credit: Steve McCurrach of

It is possible for government to make even greater use of the data on how disasters are managed and infrastructure is rebuilt. In its efforts to make public expenditure more transparent, government could find ways of publicising where the spending is taking place and on what aspects of disaster recovery. The country has seen the value of this kind of process during the Covid-19 pandemic. Data on infections and vaccinations are published daily and help build public confidence and interest in government initiatives.

Sharing data with the public Technology today is well suited to creating useful dashboards for information, for example, where data on the impact of a disaster can be represented. In the same way, the details of how the crisis is being addressed can also be tracked. The public is certainly very concerned about how these activities are proceeding, and such communication could help support a constructive national response. There is another good reason why quality professional advice adds value after a disaster: by learning from the damage caused by floods on public infrastructure like roads or bridges, the rebuilding process can create even better structures than before. This process of design adaptation can ensure than infrastructure investment goes further – producing structures that are more resilient to the demands of the future, and trends such as climate change. The KZN floods have been a devastating reminder that disaster planning and management is really the business of everyone in a municipality. It is not just the disaster management teams but all departments that should play an active part in disaster risk assessment and disaster management planning. This direct involvement will ensure that everyone’s views are considered in the assessment, and their future contribution is included in the plan. Only in this way will all functional units of a municipality be prepared for a disaster when it occurs.

By learning from the damage caused by floods on public infrastructure like roads and bridges, the rebuilding process can create even better structures than before (Credit: SRK Consulting)

IMIESA May 2022


How to reduce future flood damage KwaZuluNatal, in particular its coastal regions, suffered its worst flooding in decades in April this year. The unprecedented rainfall over a few days caused wide-scale damage to property and infrastructure, as well as loss of life. A major tragedy, it provides crucial insights for future flood mitigation across South Africa. By Peter Townshend, Pr Eng*


hile this was an extreme event, we now know from climatologists that, due to global warming, such extreme events will occur again. Lessons have been learnt about the inadequacies of the stormwater infrastructure, the need for routine maintenance to clean out large stormwater conduits, and the importance of keeping canals clear of vegetation. Preventing human settlement encroachment into streams and flood plains is an equally important priority. Going forward, measures need to be taken to minimise the adverse impacts of future floods, including environmental pollution. This includes concerted efforts to eradicate plastic litter and, in the immediate term, install litter traps in rivers to prevent it being strewn on South Africa’s Blue Flag status beaches and along attractive river banks inland and on the coast.

Robinson canal An example of a successful litter trap intervention inland is the Robinson canal in Johannesburg. The Robinson litter trap has a catchment of 8 km2 within the Johannesburg business district. On average, 80 bags of litter have been removed after even moderate rain events. Such litter traps can be installed on minor urban waterways, as well as waterways serving rural and peri-urban settlements. In terms of operation, the waterway or canal is closed off with an automatic control gate so that water flows over side weirs and through


IMIESA May 2022

a series of specially designed screens to trap flotsam and other debris and then returns to the water course relatively free of litter. The screens are designed for easy cleaning. Most of the litter comprises plastic bags, bottles, tins, polystyrene containers, tyres, clothing, and the sort. There are also dead cats, rats, dogs and other organic items caught up in these traps. Furthermore, oils are trapped and adhere to the waste. However, these oils can be removed with oilabsorbent booms.

Dry season During the dry season, when the waterflow is low, it is possible to divert low-flow, highly polluted waters into a sewer, as in the case of the Robinson canal, or in some cases through an artificial wetland to remove most of the biological waste before returning it back to the watercourse. For floods greater than a 10-year event, the regulating control gate will then open automatically, sufficient to maintain a high water level in the canal. This is to protect the debris screens so that the litter is not washed away in heavy floods, as well as to minimise upstream flooding. Even with the gate slightly open, flotsam on top of the water is still diverted through the screens. A series of these litter traps should be constructed downstream of dense urban and informal settlement areas. The collection of this litter could also be privatised to earn income from the recycled materials.

Stormwater management It will also be important to retard the stormwater peak flows through a series of retarding or retention facilities. These would be situated on open public spaces such as parks, golf courses and on sports grounds that can accept occasional flooding. Most retarding facilities are earth embankments with pipe or culvert outlets. These fixed, orifice-controlled structures increase the outflow with the rise in water level. These systems require a large space to accommodate the incoming peak flow. An alternative, which will reduce the area for flood attenuation, would be to install an automatic self-regulating gate as the outlet. These gates will open to discharge a safe maximum flow downstream so as not to cause flood damage. As the incoming flood increases above the safe flood capacity of the waterway, the gate will close slightly to maintain the safe outflow, while the excess flood water is stored temporarily behind the embankment. This results in less area being used to attenuate the flood and is therefore more effective than fixed-size outlets. These automatic control gates will also allow sediment to pass down the watercourse and will deposit litter on the retarding facility banks where it can be more easily removed than along the banks of the watercourse.

Automatic scour and crest gates For retention facilities such as urban lakes or large water features, automatic scour gates

DISASTER PLANNING & MANAGEMENT Automatic control gate releasing a fixed flow into a canal

A regulating control gate prior to installation

FIGURE 1 Routing through automatic control equipment

and/or crest gates can be fitted, which will open automatically as the water level rises to discharge a safe flow downstream, while surplus water is stored in the water feature, thereby attenuating the flood. When the flood recedes, the gates will automatically close to retain the full supply level in the water feature. It also releases sediment, which would otherwise build up in the water feature. By providing retarding facilities on many smaller streams and watercourses, the peak flows can be held back, and the water released at a safe rate over a longer period of time. These will then considerably reduce the impact of the combined peak flows and minimise damage downstream, as well as deposit litter in an area where it can more easily be cleaned up.

FIGURE 2 Larger catchments and rivers automatic canal gate

Large dams For the large dams on major rivers such as Shongweni, Inanda, Hazelmere and others, there should be large bottom outlets to lower the water level ahead of predicted heavy rains. This will provide additional capacity in the dam to attenuate the incoming large flood. Unfortunately, these dams have fixed spillways and do not have the flexibility to provide additional storage to provide protection to downstream properties or lives. However, such dams can be modified to provide this additional protection against future flood events like that which KwaZulu-Natal has just experienced. *Managing director, Amanziflow Projects

A section of the Robinson canal in Johannesburg. Installing litter traps in rivers and stormwater systems is a highly effective way to capture and remove plastic and other waste

IMIESA May 2022



Optimising energy


Load-shedding has become a frustrating problem that requires workable solutions. Bruce Munnings talks about the challenges and the search for answers.

Noupoort Wind Farm

Bruce Munnings, engineer: Electricity & Energy, iX engineers


he first time I remember loadshedding happening in South Africa was in January 2008. The bulk of electricity generation at the time was from coal-fired power stations. Electrical demand had been growing faster than new generation was being built, which led to a supply/demand imbalance. Despite the warnings on climate change, Eskom decided to build new coal-fired power stations to increase base generation. A pumped storage hydro system, Ingula, and fossil fuel generators were built to manage the peaks. Around the same time, the Renewable Energy Independent Power Producer Procurement Programme started. Between 2008 and 2022, additional new generation has been added to the South African grid. However, from Eskom’s weekly system status report, it can be calculated that at least a third and sometimes more of Eskom’s coal-fired power stations are unavailable due to planned or unplanned maintenance. Due to capital, operational and maintenance costs, climate change and corruption issues, building more coal-fired power stations is no longer considered a good option.

Breaking down the complexity of the load-shedding problem The need for load-shedding has been created for various reasons: • maintenance of coal-fired power stations • peak demand exceeds generation capacity available • environmental and climate change considerations


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• renewable energy not always available and currently limited in capacity • new nuclear power stations have not been built due to cost, corruption and other concerns • demand-side management (DSM) has not shifted enough demand out of peak demand times • energy-efficiency initiatives have not reduced demand sufficiently. Each of these items needs to be addressed in depth. However, due to the focus of this article, only some will be covered here.

Peak demand exceeds generation capacity available Figure 1 illustrates the weekly electricity demand profile. The morning peak and evening peaks are noted. The evening peak is at present higher than the morning peak. On Saturdays, FIGURE 1


Sundays and public holidays (Monday in this week), the curve is lower. Balancing supply and demand must be achieved at all times in order to keep the grid stable.

Generation: pumped storage and peaking power plants Pumped storage hydro is one of the means of balancing supply and demand. Water is pumped up during the night and used to generate electricity during the morning peak and evening peak times to balance the grid. Figure 2 provides a weekly profile of pumped storage hydro over the same period. In addition to pumped storage, liquid fossil fuels and gas peaking generators are used to meet the morning and evening peak demands. Figure 3 provides the weekly curve of generation from peaking power plants over the same period ending 6 May 2022.

Switching to energy-efficient LED lighting passed on major savings for a warehouse owner FIGURE 3

SOLUTIONS The solution is an energy mix that addresses the complex problem of load-shedding. These solutions are given in three broad categories: • Generation: dispatchable (available 24/7) or non-dispatchable (weather-related) generation. The generation mix needs to match the demand profile. • DSM tools shift demand from peak to offpeak. An example of a commonly used and effective DSM technology is geyser ripple control. Domestic geysers are switched off during peak and switched on after the peak is over. • Energy efficiency comprises a broad range of technologies and process optimisations used to enable less electricity or energy to achieve the same benefit.


Renewable generation and demand problem Supply and demand must be matched on a continuous basis, every hour, week and season. Figure 4 is a graph illustrating a typical weekly pattern taken from data on Eskom’s website in May 2022. The demand curve has a morning peak and higher evening peak. The evening peak is mainly due to residential demand, such as cooking and heating water. As can be seen, renewable generation peaks after the morning demand peak and drops off before the evening peak.

Generation Adding renewables will reduce the need for load-shedding during the middle of the day while the sun is shining. Single-axis solar PV trackers follow the sun from east to west and generate more in the morning peak than northfacing rooftop PV. Concentrated solar power with storage is significantly more expensive. However, it has the benefit of being able to generate during the evening peak. Solar PV on east-facing roofs with grid-tied inverters will be more beneficial for the grid. Adding batteries and hybrid inverters will reduce the evening peak, as well as provide power during load-shedding for essential loads such as lights, Wi-Fi, TVs and computers. Another solution is to permanently shut down unreliable and environmentally damaging coal-fired power stations and replace these

with alternatives that are safer and better for the environment. Examples include small modular nuclear reactors, which are expected to become cost-competitive over time. The issues and concerns around nuclear energy need to be addressed. And planning and communication around nuclear energy needs to continue. Green hydrogen for electricity generation is also gaining interest, although it does still have a relatively high cost. The use of green hydrogen has recently been used for heavy mining vehicles at the Mogalakwena mine.

DSM Installing domestic time-of-use meters will encourage especially higher-income residential users with battery energy storage to charge batteries while the sun is shining, or charge at a lower-cost, off-peak tariff and use the stored energy during peak times. Time-of-use tariffs and possibly future real-time pricing will encourage shifting the load out of the peaks – e.g. tumble driers, dishwashers, and swimming pool pumps.

Electric vehicles can also be charged during off-peak. Some vehicles are now equipped with vehicle-to-grid capacity and can be used for DSM.

Energy efficiency Examples of energy-efficiency interventions include the following: • Aeration of municipal wastewater treatment works: traditional surface aeration is very energy intensive; however, there are newer aeration technologies that are more efficient. • Green building elements: these include ceiling insulation, low-emissivity glass, adjustable blinds to manage sunlight, and natural ventilation to reduce electricity used by air conditioning. • LED lamps are now available at 210 lumens per watt. Careful planning of new lighting installations or changes must also address glare and discomfort. Energy-efficiency opportunities must remain a focus area, as these are often the leastcost options.

IMIESA May 2022




clean energy and autonomy Renewable energy installations at St. Cloud wastewater treatment facility, Minnesota, USA


he latest update to the South African government’s Integrated Resource Plan (IRP) places increased emphasis on the greater integration of renewable energy generation. In addition, the IRP gives municipalities permission to consider alternative ways to generate electricity through decentralised alternatives that take pressure off the national grid. It’s no secret that Eskom’s ageing power stations and a growing maintenance backlog have made load-shedding a regular feature for the foreseeable future. Aside from the economic fallout, scheduled and unscheduled power cuts have a devastating impact on municipal ser vice deliver y, especially in terms of water purification and wastewater management. The shortfall in electrical infrastructure investment also fails to close the gap on regional community electrification projects. Within this context, clean-energy-powered microgrids help to bridge the divide while lowering our dependence on fossil fuels. These microgrids can typically range in output from as low as 10 kW to over 100 MW. They are diverse in nature and size, depending on the load, location and resources. However, with few exceptions, their power source is derived from renewable energy. Options include solar photovoltaic (PV) systems, wind turbines, hydropower and biomass, or some hybrid of these that incorporates diesel or gas generation as a backup when the sun sets, or the wind drops.


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Before rushing in, though, municipalities need to do their homework to ensure the microgrid systems selected meet the requirements and deliver according to expectations.

For South African municipalities, microgrids present a strong business case in terms of power security and sustained supply, especially for critical infrastructure during downtime on the national grid. By Shireen Sayed

Battery storage Energy storage, which includes batter y storage, plays a critical function in terms of making microgrid energy supply predictable and readily available on demand. Furthermore, it improves microgrid stability by acting as a buffer against renewable intermittency and mitigates load uncertainties. Therefore, choosing the best fit-forpurpose batter y storage system (BSS) is crucial since this represents one of the highest-cost items within the overall microgrid setup (between 20% to 30% of the overall capital cost over its lifespan). In today’s market, batter y options include redox flow, lead-acid, Li-ion, nickel-cadmium, and nickel metal hydride. Due to their simplicity, Li-ion and leadacid batteries are popular for the rural microgrid market. Either way, BSS optimisation and application requires a comprehensive understanding of how batteries behave under various operating conditions. These include exposure to temperature variations, as well as charging-discharging. Typically, a microgrid comprises several batter y storage units, with each unit having a var ying degree of output capacity depending on factors such as initial

Shireen Sayed, managing director, Aspire Project Management

state of charge (SOC), efficiency, ageing (i.e. number of cycles), and temperature conditions. Ideally, the BSS should function as a well-synchronised system.

Battery management system To be able to manage any differences between the various batteries, and to ensure stability, a battery management system (BMS) is required to monitor and control vital functions of the BSS in real time. The BMS relays information such as temperatures, voltages, currents, maintenance scheduling, batter y per formance optimisation, failure prediction and/or prevention, as well as batter y data collection/analysis. The function of battery optimisation must be considered as part of the overall microgrid design right from the onset to achieve maximum results from the storage system, as well as from the overall ability of

A microgrid installation for a small town

According to the International Renewable Energy Agency, studies show that battery storage worldwide is predicted to grow from approximately 2 GW in 2017 to around 175 GW in 2030…”

COMMON MICROGRID APPLICATIONS - Municipal infrastructure - Urban and rural electrification - Wastewater treatment plants, water purification and reticulation - Backup power for cities and towns - Transportation – e.g. rail and electric bus fleets

the microgrid to respond adequately to the energy demand. For microgrid applications, there are some quick wins in terms of achieving optimisation of the BSS. These include: - on-the-ground optimising, incorporating the correct positioning of batteries, adequate ventilation or insulation of the batter y storage facility - fully trained resources to carr y out repairs and maintenance - the quality and technology of the energy storage systems must be carefully selected and designed. According to the International Renewable Energy Agency (IRENA), studies show that batter y storage worldwide is predicted to grow from approximately 2 GW in 2017 to around 175 GW in 2030, and that costs will continue to fall as technology improves. Technology gains include longer life, increased numbers of cycles, and improved overall storage performance.

microgrid footprint in line with their energy requirements. Any additional power that is not used can be pushed into the transmission grid and offset as savings to the municipality. Revenue streams can also be guaranteed by installing prepaid smart metering to ensure payback on the initial investment and longerterm profit generation. In addition, investor confidence is restored when there’s an assurance of sustained power to support current and future industrial and commercial expansion within the municipal zone.

Case studies from Africa and the world As statistics from IRENA and allied bodies show, the traction for microgrids and renewable energy in general is rapidly

Typical microgrid from renewable energy sources

Battery storage Converter

Benefits for municipalities In addition to a degree of autonomy, towns and cities have a greenfield opportunity to map out their current and future

gaining ground in both the developed and developing world. On the African continent, a prime example is Tanzania. According to various literature, just under 40% of the population of Tanzania had access to electricity in 2017. With a concerted effort from the Tanzanian government, this deficit is steadily narrowing. Today, Tanzania is recognised as a regional leader in microgrid deployment, with over 100 microgrid systems ser ving businesses and local communities. These microgrids are either governmentowned or owned by private developers selling electricity back into the national grid through power-purchase agreements or sold directly to end consumers. While Tanzania has been successful in the deployment of microgrids, there have been challenges, one of which has been funding.

National grid Renewable energy source

Energy to consumers

IMIESA May 2022


RENEWABLE ENERGY & ELECTRIFICATION Typical microgrid components

Working towards



Power for residents: Netherlands The first microgrid installation in the Netherlands was at a holiday park in Bronsbergen, approximately 100 km west of Amsterdam. A microgrid was built to provide 208 homes with 315 kW of solar-generated power, with an energy storage capacity of 700 kWh. The microgrid is connected to the national grid via a 10 kV line.

Clean energy for wastewater treatment: California A proposed microgrid project is under way for the wastewater facilities in McKinleyville Community Services District (MCSD) in California, incorporating the existing diesel generators with solar PV and battery storage. The MCSD serves an estimated 16 900 residents and provides key services such as clean water reticulation, wastewater processing, maintenance of parks, etc. The outcome of the project is a wastewater treatment facility that has a target of net-zero emissions. In addition, the microgrid will provide the facility with energy resilience.

Conclusions In all three of the above case studies, there’s a similar, solution-specific role for microgrids across South Africa, and for our municipalities, working in conjunction with independent power producers to speed up their implementation. Power supply has a direct impact on ser vice deliver y. And the lack of power for water reticulation or wastewater treatment


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can have catastrophic implications. Here, microgrids give municipalities greater control to improve energy efficiencies and security, as well as flexible options in terms of modularity and scalability. As with any infrastructure investment, the starting point is a comprehensive needs analysis, which includes researching optimum BSS and BSM technologies, existing and future distribution networks, and operations and maintenance costs. Studying and learning from international microgrid experience within the municipal space is equally important. Funding mechanisms are available to support the deployment of microgrids in Africa. However, the financial modelling must make a sound business case for lenders and investors. A positive step in this direction is the South African government’s decision to increase the non-licensed threshold to 100 MW for independent power producers. This opens the door for more microgrid opportunities. In municipal deployment, the main aim is to produce clean electricity at the lowest cost through optimisation. In this respect, microgrids can ser ve as a catalyst for muchneeded economic recover y and growth. Ultimately, microgrids should form part of all municipal strategic development plans now and into the future.

This is an edited version of a paper presented at the IMESA 2021 Virtual Conference. The full paper can be downloaded at conference-2021.

Yovka RaytchevaSchaap, associate: ESD Consulting and Project Management, Zutari

ew regulations introduced in terms of the National Energy Act (No. 34 of 2008) will make it a mandatory requirement for designated building owners to display a certified Energy Performance Certificate (EPC) at the entrance to their properties. The regulations were gazetted in December 2020 with a two-year deadline for compliance, affecting public buildings over 1 000 m2 and non-residential private buildings over 2 000 m2. The South African National Energy Development Institute has defined the process and undertaken the development of tools and guidelines to prepare all stakeholders and enable the efficient implementation of the EPC process. In this respect, consulting engineering and infrastructure advisory firm Zutari is well placed to assist clients with EPC compliance, and allied interventions, given its deep expertise in building services, including building management systems (BMS) and environmentally sustainable design (ESD). Comments Yovka Raytcheva-Schaap, associate: ESD Consulting & Project Management, Zutari: “We offer a wide range of services – from design and construction supervision through to commissioning, building tuning, energy analysis, digital twinning and strategy development for netzero carbon, water and waste performance.”

Up- and downstream services Zutari offers both up- and downstream assistance with the EPC process. Upstream assistance includes identifying and verifying eligible buildings; obtaining records and confirming the performance period, occupancy type, occupied area, energy sources, and energy consumption calculation of preliminary performance and rating; and the submission of packaged building data to an independent inspection body for verification and issuing of an EPC certificate. In turn, downstream assistance includes automation of data collection and verification via BMS for subsequent EPC ratings (implementation of a simple digital twin), and identifying interventions for improving energy performance towards net-zero carbon.


Correct cabling specification key


Solar photovoltaic (PV) has become an increasingly popular solution for consumers who want to get off the grid or supplement grid-tied power. But faced with economic and industry challenges, contractors may be tempted to boost their bottom line by reducing costs on these projects – and cabling is an easy target.

Svilen Voychev, managing director of Valsa Trading


ith the current pressure felt by supply chains, contractors are stressed to meet the demands of consumers. They may turn to low-budget cables, which are not suitable for solar farm conditions such as voltage and UV exposure,” explains Svilen Voychev, managing director of Valsa Trading. “It also sometimes happens that suppliers present contractors with cabling that looks the same as copper cabling, but is in fact copper-clad aluminium, which is noncompliant with SANS or NRCS regulations and has poor resistance and insufficient conductivity,” he continues. The risk of fire and electrocution becomes more prominent when the wrong cables are selected. This also reduces the effectiveness of protection accessories.

UV exposure A common point of failure in PV systems is the connections between panels. The DC connectors from the panels to the inverters can also be a pain point if the wrong cabling is used. “People underestimate the importance of a cable’s UV rating – this plays a vital role in South Africa. A PV farm has a lifespan of more than 25 years in some cases, and the cabling has to be able to stand this test of time,” says Voychev. “Some of the cabling we stock undergoes extreme treatment to withstand radiation almost to nuclear levels. This is what contractors should be looking for if they want to offer installations that last.”

Hardy accessories make it or break it Cable accessories are also vital in the installation to ensure that cabling is protected from damage that may lead to failure or electrical faults. “Too often, we see that installers haven’t even budgeted for

accessories that could mitigate a range of problems. Something as simple as a cable tie could greatly impact the system reliability and performance, preventing cables from being sliced and worn down. But again, not just any cable tie will do. They need to be UV-rated and tested,” Voychev explains. Voltage is also an important consideration. “High-voltage commercial installations mean that temperatures are bound to rise – and the connectors are often the first to fail in these cases. Using cheap imports that aren’t designed for these applications is sure to lead to system failure.” Voychev recommends that contractors who are tasked with solar PV installations familiarise themselves once again with the National Regulator for Compulsory Specifications (NRCS) Act (No. 5 of 2008) and the specifications under the NRCS Electrotechnical business unit. Contractors must also ensure they comply with the latest edition of SANS 10142-1 ‘The wiring of premises'.

IMIESA May 2022


Construction in the cloud In a survey conducted by RIB CCS in Q4 2021, construction industry respondents singled out cloud computing as the most critical area to invest in, followed by building information modelling (BIM), mobile technology and integrated technology platforms.

Peter Damhuis, vice-president, RIB CCS


efore cloud computing was widely adopted by the industr y, personnel on construction sites had to install IT infrastructure, printers and – in some instances – a dedicated ser ver room to facilitate the exchange of data between teams. The advent of cloud computing has changed this scenario significantly, and in the process enhanced programme and project management efficiencies, says Peter Damhuis, vice-president at RIB CCS. “For example, programmes such as BuildSmart can be accessed from wherever the various team members are located and provide one source of information for ever yone. All of the manual processes of seeking information, submitting requisitions and creating orders can now be completed in the cloud – in real time


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– improving the outcomes for ever yone involved,” he explains. Damhuis says when he started conducting conversations about moving to the cloud with his clients a few years ago, there was little interest in doing so. “Those same clients are now asking us to help them make the transition. I believe the Covid-19 pandemic, Microsoft and other players in the industr y are major drivers behind this,” he continues.

Ability to store unlimited data The most obvious benefit of cloud computing is the ability to store masses of data relating to each project in a secure environment. Cloud storage protects data from the threat of physical loss or damage and makes it accessible from anywhere, anytime. Most cloud operators offer duplicity (a replica of your information in another data centre), which provides added protection against data loss and continuity of ser vice.

Potent data processing at hand In the past, the processing of 3D models required laptops with massive engines, video cards and high processing speeds. With cloud computing, model optimisation and file format translation can be conducted in the cloud centres, which are

equipped with top-of-the-range equipment and limitless processing power. As a result, working on a 3D model now requires looking at the optimised data in the cloud, rather than having to use a desktop computer to create it. Another compelling reason for choosing the cloud is the concept of generative design. This is an iterative design process that uses the full power of the cloud to compute design alternatives. “For example, if the construction team were building a complex arch, a generative design would calculate the optimum span, shape and load,” Damhuis explains.

A bird’s-eye view of all operations For a long time, the segregation of information on job sites has not been conducive to working in an integrated way. As Damhuis points out, each job has its own information, but once construction companies start compiling data over numerous sites, they’re able to track trends on projects and make better executive decisions. In today’s cost-constrained environment, ensuring that projects are completed on time, to specification and within budget is vital for commercial success, and the optimum platform for executing this is via the cloud.

INFORMATION & COMMUNICATIONS TECHNOLOGY Tandem offers simulation and predictive modelling capabilities, based on real-world conditions of the building and its environment, thus reducing risks and cutting project costs



utodesk’s latest cloud-based Tandem software produces a digital reference model of any building, bridge or road, incorporating BIM data that includes design, construction and service data. The reference model becomes a dashboard for the project and a database of its assets, making it possible to track, manage and maintain these assets over time. The model is responsive, automatically updating as data is supplied. Tandem’s Facility Templates enable project teams to specify the owner’s data requirements up front, ensuring data

FOR AEC PRACTITIONERS delivery is standardised and consistent. It also enables architecture, engineering and construction (AEC) project teams to collaborate easily, and to view progress (and asset performance) historically or currently. This seamless collaboration functionality enhances both efficiency and productivity.

Management and integration Before the advent of digital twin technology, the management and integration of different data sources was a challenge for AEC project teams, sometimes resulting in inefficient workflows, costly errors and delays. Project handovers involved the lengthy process of

converting large volumes of analogue data (from different silos) into a single digital format. Using this method, a significant volume of data was wasted. “Digital twin technology is already utilised in manufacturing, as well as the oil and gas industry, where it has demonstrated that it can improve the management of production and drive efficiency,” says Chelsey Turner, segment leader: Infrastructure at WorldsView, a value-added distributor of Autodesk solutions across Africa. “The introduction of Autodesk Tandem, designed specifically for the AEC sector, will bring a host of benefits into the make-build space.”

TECHNOLOGICAL INNOVATION IN THE CONCRETE INDUSTRY STARTS WITH MAP PRODUCTS. • • • • • • • • • • • • • • • • • • • Learn more at Tel: +27 11 552 8476 Email:

Precast concrete plasticising admixtures Ready-mixed concrete plasticising admixtures Extended workability polymers Set retarding admixtures Hardening accelerators Viscosity modifying admixtures Form release agents Synthetic fibres Pozzolan-activity mineral additions Permeability-reducing admixtures Water-repelling admixtures Anti-washout admixtures Expanding agents Drying shrinkage-reducing admixtures Clay mitigating admixtures Pumping aides Air entraining and foaming agents Concrete rescue packs Evaporation-retarding admixtures

A STUDY: WATER SECURITY AND CLIMATE CHANGE RISKS FOR MUNICIPALITIES This study (done in support of the CSIR Greenbook) presents a first order assessment of current and future water security risks for municipalities across South Africa, as a result of both expected climate change impacts as well as future population growth scenarios up to 2050. By Dr James Cullis


opulation growth and economic development coupled with the likely impacts of climate change pose serious water security challenges for municipalities across South Africa. While large parts of Southern Africa are likely to experience drying conditions as a result of the impacts of climate change, it is not all doom and gloom from a water security perspective. Due to variability in the impacts of climate change, some areas of South Africa could see some potential benefits, while other areas will almost definitely be losers. Particular hotspots of concern are: • the south-west of the country, due to the likelihood of decreasing rainfall and increasing population growth • to a lesser extent, the extreme north of the country, due to increasing temperatures and additional population growth partly driven by increasing regional migration. Conversely, the eastern part of the country is expected to see a possible average increase in rainfall. Even in areas considered to be winners due to the potential for increasing precipitation, there is still likely to be increasing risks due to greater inter-annual variability and greater intensity of rainfall events and associated flooding. A study done as part of the Long-Term Adaptation Scenarios (LTAS) research programme


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showed that 30% of bridges, 19% of dams and 29% of powerline crossings have a high to very high risk of an increase in design capacity floods. It must be noted, however, that some towns – particuarly rural ones – are likely to also experience a decline in population, particularly due to urban-rural migration or if local industries close or proposed developments do not materialise, which could reduce the overall water security challenge even in a drying climate.

A general climate change risk equation A general risk equation was developed to determine the current and future water supply vulnerability for all municipalities across South Africa. It combines both the anticipated climate change impacts on water availability and development risks (due to an increase in population and an associated increase in water demand). The general risk equation recognises that risk is not just based on the direct exposure to climate change (for example, the change in precipitation or run-off) but is also dependent on the vulnerability of each town in terms of its current and future water demand and water supply options. Future water supply risk is therefore affected by both the availability of water – either from surface or groundwater

Dr James Cullis, water resource engineer and expertise leader: Sustainability Consulting, Zutari

sources that are impacted differently by climate change – and by changes in demand, driven primarily by population dynamics, but also affected by increasing temperatures and climate change. The relative change will vary between towns and cities based on their location and future development potential, and must be taken into consideration for planning purposes. This is a first order estimate of the relative future water security risks for all local municipalities across South Africa. Given the high-level nature, several assumptions have been made that would differ from more focused analysis of individual water supply systems. As a result, it should not be taken as the final climate change risk profile for any specific individual local municipality, but rather as an indication of overall trends and highlighting key issues to be investigated further. Additional analysis is required specifically as regards the unique nature of the water supply system to each individual municipality, particularly when integrated with a regional or bulk water supply system.


FIGURE 1 Current (top left) and future water security risks (demand/supply) with a 10th (dry – top right), 50th (median – bottom left) and 90th percentile (wet – bottom right) climate change exposure scenario, based on local surface water impacts only (E1), and high population growth scenario for municipalities by 2050

For more information on the risk equation and the results of the study, refer to the Greenbook Story Map for Water Supply Risks (

Results Overall, the results of this study indicate that the local municipalities with the highest water supply vulnerability, both current and future, are located in the Eastern Cape and parts of Mpumalanga. This can be ascribed primarily to the fact that these places have limited existing water supply capacity as a result of the current lack of basic water supply services and infrastructure. In future, most municipalities will see an increase in water supply risk either as a function of increasing population growth or exposure to potential climate change impacts for both supply and demand (evaporation), or both. There are, however, one or two municipalities that could experience a reduction in water supply risk, either a result of a declining population, or due to the positive impacts of increasing precipitation and surface water availability due to climate change. Even under the 90th percentile ‘wet’ scenario,

there are several municipalities, particularly in the Western Cape, that will still experience increasing water security risks, while in some cases any increase in water security risk due to climate change is matched by a reduction in demand. Some of the municipalities on the northern border are expected to see significant population growth as a result of migration from other countries, which when combined with likely significant increases in temperature for the inland areas, could contribute to a significant increase in demand and water security risks, even if the area could experience an average increase in rainfall. This regional migration is also likely to be driven by differential climate impacts. In contrast, there could be a reduction in water supply vulnerability for some more rural towns and municipalities as these experience population declines due to internal rural-urban migration even in areas that are likely to see drying and reduced availability of existing water supply options. The study also looked at the difference in the climate change impacts on local surface water

supply options as compared to the potential benefits from an integrated system. The results highlight the importance and potential benefits of being connected to a diverse and more integrated bulk water supply system. In this scenario, the major economic hubs of Johannesburg, Durban and Cape Town – which are also the major centres for urban water demand – are the most likely to benefit from the mitigating impacts of being connected to a highly integrated bulk water supply system. For the accompanying Figures 1 and 2: • a value of 1 – implies that the demand and supply of the municipality are equal • a value of less than 1 – means that there is surplus of supply • a value of more than 1 – means that either the demand is too high, the supply is too low, or both. Climate change will impact on both water supply and demand, affecting overall water security risks and vulnerability.

Recommendations Adapting South African settlements to increasing water supply risks includes not only adapting to climate change impacts, but

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FIGURE 2 The relative impacts of climate change and population growth on water supply risks by 2050 for all local municipalities in South Africa (Source: Greenbook. Cullis et al., 2019)

also to future population growth and development requirements. Consideration also needs to be given to improved water resources management, improved monitoring, improved operational efficiencies, and investments in ecological infrastructure. Recommendations for climate change adaptation for improved water security include the following: • Improved monitoring, operation, maintenance and management of existing bulk water supply infrastructure is critical in terms of managing future water supply requirements and current water use efficiency. • Investments must be made in more diverse water supply options, including conjunctive use (surface and groundwater), and alternative supply options such as desalination and reuse.


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• Better catchment protection and investing in ecological infrastructure is required, such as the removal of alien invasive plants and the rehabilitation and protection of wetlands. • Compliance with ecological water requirements will also become even more critical in the face of increasing demands from population growth and climate change. • More detailed assessments of climate change risks for individual towns and water supply systems need to be undertaken including bottom-up assessment of climate change risk. • Increased investments in monitoring surface water and groundwater resources are required. • Improved cooperation between local, national and provincial departments, and different water users, is critical for the efficient operation of increasingly

complex and sensitive integrated bulk water supply systems. • Continuous monitoring and communication with stakeholders are important, particularly during periods of drought where users are critical in terms managing demands. • Improved water use efficiency and reduced unaccounted-for water is important, but it must be noted that the more efficient users become, the harder it is to manage demand during periods of drought. With the urban areas being the focus for most of the future population growth, particularly in developing countries, it is critical that urban water security is a priority focus area for all national and local governments. While a national study like this one can provide some general insights and highlight key priorities, it is critical that each municipality be considered from an individual bottom-up perspective. A separate United Nations University study of the potential economic impacts of climate change in South Africa showed that the existing integrated bulk water supply system provides some resilience to the potential impacts of climate change by being able to manage water supply from different parts of the country and utilising dam storage efficiently. The benefits of this, however, will vary significantly between different towns dependent on their current and future water supply sources and the ability to manage increasingly complex bulk water supply systems and changing demands. For example, a large number of towns are already highly dependent on groundwater, while other towns, particularly in the coastal region, are already starting to implement desalination and reuse. Improved management and the integration and diversification of alternative supply sources is critical to supporting the transition to more water-resilient and water-sensitive towns and cities across South Africa.


Solutions to bring water to

OUR PEOPLE Proudly South African company SBS® Tanks has been a leader in the water security space for almost 25 years. The water specialist has a legacy of building for better and is well positioned to work with consultants, engineers, government and municipal leaders to ensure that the mandate of access to water for all is achieved quickly.


s an established company with a local manufacturing facility, we are able to respond quickly. Our SBS water storage tanks can deliver lifegiving water to a community in a matter of days,” says Mava Gwagwa, director: New Business Development, SBS Solutions SA, a Level 2 BBBEE Contributor. “SBS tanks can be installed in very remote areas and do not require access roads to be built beforehand. Our tanks are modular and can be constructed in a matter of days and commissioned immediately.” Rugged terrain and harsh environmental conditions are no challenge for the SBS installation team. There are no on-site heavy equipment or machinery requirements, and the panels and fittings can be transported to the site on off-road vehicles or even carried where necessary. As a company, SBS is also ISO 9001 and ISO 45001 compliant, and SANS 10160 accredited. From donating water storage tanks, developing modular products and elevated solutions, improving the speed of installation and commissioning of reservoirs, to providing effective liner solutions for existing ageing infrastructure, SBS has worked in partnership with consulting engineers, infrastructure development teams and agencies, national government and regional municipalities to deliver effective, durable and low-maintenance water storage solutions across South Africa.

Benefits SBS Zincalume® steel panel water reser voirs offer the following benefits: • r apid installation and immediate commissioning – no lengthy build and curing time • a n extended lifespan expectation of 65 years • over 500 sizes with a variety of uses from potable to effluent and process water storage • liquids are stored in a liner, reducing the risk of corrosion of steel panels and leaks • liners carr y a 10-year no-leak warranty • capacities from 7 000 litres to 4.4 million litres • i n projects where mass storage is required, multiple SBS tanks can be installed and connected, allowing for fast and continuous water supply to communities, even during routine system maintenance, ensuring ongoing service delivery • engineering, project management support and after-sales ser vice from a trusted and reliable partner. At a time when most businesses are purely profit-driven, SBS has continued to support the development of infrastructure for rural regions, working to empower local communities, employing local service providers and labour for site preparation, and offering skills development training. In partnership with municipalities and Salga, SBS regularly donates water security solutions that build for better, resulting in the provision of essential water supply to schools and communities. “At SBS, we believe in doing good while doing good business. Helping municipalities and government deliver on their mandate of supplying water to communities brings hope

Looking for a trusted partner who will help you specify and deliver a water or liquid storage solution for a municipal project? Contact your SBS partner today, visit or email for more information. Call Mava Gwagwa +27 (0)83 639 2702 or ask to speak to a municipal expert on 0860 482 657. for a better tomorrow for all,” says Gwagwa. “We are proud of the fact that our water storage tanks have been installed across South Africa, into Africa and across the world. SBS can confidently say that we make a difference – fast.”

TOO LONG, DIDN’T READ? SBS Tanks supplies a range of over 500 sizes of water storage tanks suited for the municipal, commercial, mining, agricultural and domestic sectors. Capacities range from 7 000 litres to 4.4 million litres. They can be used for the storage of water and various other liquids, including numerous chemicals, effluent and process water, and can be installed in very remote locations with no electricity or road access requirements. IMIESA May 2022



Summary: National Green Drop Report An analysis of the recent results from the Green Drop Report


Department of Public Works key performance areas district municipality local municipality water services authority w astewater treatment works

WHAT IS THE GREEN DROP PROGRAMME? This programme focuses on wastewater quality management and promotes compliance of WWTWs with the national Wastewater Discharge Standards. It measures and compares the results of the performance of WSAs and their providers via a standardised scorecard, and subsequently rewards (or penalises) the municipality upon evidence of their excellence (or failures) according to the minimum standards or requirements that has been defined. Green Drop seeks to protect the environment from hazards associated from polluted water.


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INCENTIVE-BASED REGULATION Incentive-based regulation is an innovative and uniquely South African response to challenges in the water sector. The Green Drop programme seeks to induce changes in the behaviour of individuals and institutions to facilitate continuous improvement and the adoption of best practice management of wastewater networks and treatment systems. Consequently, progressive improvement and excellent performance are recognised and rewarded.

WHO WAS AUDITED? 995 WWTWs • 144 WSAs (850 systems) • 12 DPWs (115 systems) • 5 private and state-owned utilities (30 systems) Audit period: 1 July 2020 to 30 June 2021

WHO ARE THE AUDITORS? 96 lead and assistant inspectors were trained. They qualified after achieving a threshold examination score.

The audit covers: Sewer network Sewer pump stations Treatment systems On-site sanitation

4 OUTPUTS FROM 2022 AUDIT PROCESS 1 A Green Drop audit score for each wastewater system assessed, which is aggregated into an organisational (overall) score, expressed as a %

2 A Cumulative Risk Rating for each wastewater treatment works, expressed as a % 3 Technical Site Assessment (TSA) score for selected collector and treatment systems 4

inspected, expressed as a %. Physical site inspection is done on 1 to 2 systems to confirm findings on desktop audit A collective VROOM cost for all treatment systems within each WSI, expressed in ZAR


VROOM = Very Rough Order of Measurement. This was a key output for the Green Drop audit process that provides insights on the state of the key elements of the wastewater treatment infrastructure and provides an order of magnitude estimate of cost to return the infrastructure to a functional condition

Province Eastern Cape Free State

Total VROOM cost R653 719 530 R929 245 540

Gauteng KwaZulu-Natal Limpopo Mpumalanga Northern Cape

R3 179 851 300 R508 270 200 R300 479 100 R832 735 300 R503 962 740

North West Western Cape Total

R493 689 500 R739 691 155 R8 141 644 365

5 KPAs ON THE AUDIT SCORECARD 1 Capacity Management 2 Environmental Management 3 Financial Management 4 Technical Management 5 Effluent and Sludge Compliance



City of Ekurhuleni, Lesedi LM, iLembe DM, uMgungundlovu DM, Witzenberg LM, Bitou LM, Drakenstein LM, City of Cape Town, Saldanha Bay LM, Mossel Bay LM, and Sasol Sasolburg


% of systems in a critical state

Limpopo Northern Cape

78% 76%

North West Free State Mpumalanga Eastern Cape Gauteng

69% 67% 43% 39% 15%

KwaZulu-Natal Western Cape

14% 11%

89% of DPW systems are in a critical state

GREEN DROP SCORES OF WWTWs: ≥ 90% is regarded as excellent and is awarded Green Drop Status ≤ 31% is regarded as a dysfunctional system and is placed under regulatory focus

2021 Number systems scoring ≥ 90% Number systems scoring ≤ 31% Number risk ratio

2013 23 334

60 248



Vast majority of rural municipalities struggled to score more than 50% 102 DPW systems scored ≤ 31%


2013 Green Drop Score

2021 Green Drop Score

Eastern Cape Free State

65% 51%

51% 26%

Gauteng KwaZulu-Natal Limpopo Mpumalanga North West Northern Cape Western Cape

83% 82% 45% 44% 47% 44% 85%

68% 68% 29% 49% 30% 41% 84%

2021 Green 2021 Green Drop Certified Drop Critical ≥ 90% State ≤ 31% 48 64 7 3


9 20 50 33 33 59 18

• The most prominent risks were observed at treatment level, and pointed to works that exceeded their design capacity, dysfunctional processes and equipment (especially disinfection), lack of flow monitoring, and effluent and sludge non-compliance • Infrastructure is often being upgraded with the full system being taken out of commission, allowing untreated wastewater to bypass the plant directly to the water body • Non-payment of contractors, laboratories and other professional service providers is widely found, leading to services not being rendered, delayed or discontinued • Vandalism and theft of electrical cables, equipment and civil structures result in systems being inoperable for extended periods, with few WSAs having effective anti-vandalism strategies or contingency plans in place • In general, there is a low level of awareness on energy efficiency and conservation exists at most WSAs

There has been a general decline in the condition of our wastewater systems since 2013. All wastewater treatment systems should meet the Green Drop certification standards. I am confident that we will get back on the right trajectory. This year’s assessment has provided us with a baseline and the platform to launch the turnaround.” – Dr Sean Philips, Director General, Department of Water and Sanitation

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Water-Check programme sets the benchmark Maintaining the highest drinking water standards


he South African Bureau of Standards (SABS), together with its Technical Committee 147 – Water (SABS/ TC 147), has been working to revise and update the requirements of the national standard for drinking water in South Africa. The draft seventh edition of the national standard, SANS 241 ‘Drinking water quality’, is now open for public comment. The draft document (SANS 241 Ed7 DSS) combines the technical requirements from the previous Part 1 and Part 2 of SANS 241: 2015 and stipulates the revised framework for drinking water quality risk management and specifications for drinking water quality in South Africa. All water that complies with the requirements of SANS 241 is deemed to be safe for human consumption. “While there are existing national standards to guide the quality of drinking water in South Africa, it is essential that these standards are reviewed and updated to reflect the latest knowledge and research – to ensure that quality drinking water reaches our communities,” explains Jodi Scholtz, lead administrator, SABS. “Microbiological, physical, aesthetic and the chemical determinands of water have been revised according to the latest research and the framework has been updated to incorporate risk management, as well as monitoring and evaluation,” Scholtz continues. SANS 241 is referenced in the Water Services Act (No. 108 of 1997) and in the Local Government: Municipal Structures Act (No. 117 of 1998). All individuals and organisations involved in the process of delivering quality drinking water to communities will need to ensure that they are familiar with the changes contained in the updated standard.

RECORD NUMBER OF NATIONAL STANDARDS PUBLISHED IN 2021 The SABS published 414 national standards in the financial year ending 31 March 2021. Of these, 127 new standards were published. (In 2020, 359 national standards were published and 241 in 2019.) With approximately 7 400 South African National Standards available, organisations have access to technical specifications on almost every product, service and management system in the South African market.


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A proficiency testing scheme is a crucial part of the laboratory quality system, and participation is a mandatory requirement of SANS/ISO 17025 accreditation


In all instances, it is essential to check water quality compatibility before use. Testing aids in making informed decisions about water use, water and its potential treatment

riving quality assurance in South Africa, and further afield in Africa, the SABS Water-Check programme is fully accredited in terms of SANS/ISO 17043 ‘Conformity Assessment – General requirements for proficiency testing’. SABS monitoring and regular water quality testing are vital for maintaining reliable and safe water sources, as well as eliminating the potential health risks associated with pollution. Within this context, SABS proficiency testing determines the performance of individual laboratories for specific tests or measurements and is used to monitor their continued performance. This process is referred to as interlaboratory comparison or a proficiency testing scheme – or, in the case of the SABS, WaterCheck. SABS Water-Check services are provided to laboratories across Africa. A proficiency testing scheme is a crucial part of the laboratory quality system, and participation is a mandatory requirement of SANS/ISO 17025 accreditation. As this term implies, proficiency testing compares the measured results obtained by different laboratories. Furthermore, SANAS regulatory documents R-48 and R-80 require that accredited laboratories participate in proficiency testing schemes to cover their scopes of accreditation. As far afield as Dar es Salaam, the SABS currently has more than 150 customers and is the only African SANS/ISO 17043 accredited laboratory.


Strategy to improve


for municipalities The Development Bank of Southern Africa (DBSA) is looking to replicate successes in the energy sector by implementing a National Water Programme.


e have looked at the Renewable Independent Power Producer Programme (REIPPP) that has been successful due to its specific finance solution, as well as the Independent Power Producer Office that is a centre of excellence for anyone wanting to be involved with renewable projects,” explains Johann Lübbe, disruption specialist, DBSA. To replicate this model in the water and sanitation sector, the DBSA is working with government to establish a National Water Programme. The water programme will build on two of the bank’s current goals: • offering a centre of excellence for waterbased projects to develop capacity and provide support to project owners (like municipalities and water boards) to take projects forward with regard to feasibility studies, bankability and implementation • promoting blended funding options for financiers of new water-related projects in the country. Within the National Water Programme, there will be sub-programmes to address the following: • scale and escalate water reuse projects across the country • non-revenue water, focusing on both physical and revenue losses

Johann Lübbe, disruption specialist, Development Bank of Southern Africa

• wastewater treatment challenges • off-grid sanitation programmes • ecological infrastructure programmes • desalination • agricultural water-use projects. “The DBSA addresses the entire water infrastructure value chain through this programme. It will create an enabling environment and provide support and standardised approaches to problems. When looking at REIPPP, once investors, developers and consultants became familiar with the documentation and approach, pricing was reduced. Reinventing the wheel with every project is inefficient at best. A standardised approach will reduce costs as well as accelerate the implementation of projects,” says Lübbe. This programme aims to enhance the private sector’s investment in projects, as well as capitalise on its expertise to assist in supporting under-resourced municipalities with the operation and maintenance of its water services infrastructure. “We are not talking about privatisation, but are focusing on management contracts that assist with the maintenance and operation of infrastructure, while ensuring that there is skills transfer within a municipal space,” adds Lübbe.

Alternative funding solutions The water sector is notoriously difficult to fund. According to Lübbe, two of the most popular financing options for infrastructure are municipalities raising funding on their balance sheets and public-private partnerships (PPPs). “Not all municipalities can raise sufficient funding on their balance sheets and PPPs cannot work in all cases. We therefore need to look at blended finance. The private sector does not always have the structures and mechanisms to invest in water infrastructure.

We need to bring in credit enhancements from development finance institutions, first-loss facilities and guarantee products that can maximise the portion of private investment. Government can then fill in any finance gaps,” he states. Lübbe adds that climate finance should be facilitated and emphasises the need to consider the operation and maintenance of water infrastructure when applying for funding.

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Linnhoff asphalt plant overcomes logistical challenges on TEMA ROAD PROJECT A Linnhoff TSD1500 MobileMix asphalt plant achieved remarkable progress on the high-profile grade separation of the Tema Motorway Interchange project in Ghana.


he roundabout at the interchange had been troubling motorists with its severe traffic congestion, which often exceeded 1 km during peak hours, and had become a pressing issue for the government to tackle. The Project for the Improvement of Ghanaian International Corridors was

therefore implemented – one of the priority projects proposed in the West Africa Growth Ring Corridor Master Plan. A US$57 million (R909 million) grant from the Japan International Cooperation Agency soon followed in aid of this project. The motorway interchange at Tema, Ghana’s largest port city, forms the crossroads of two of the country’s busiest international corridors: the National Highway 1 (N1), which hugs the Ghanaian coastline virtually all the way between its borders with Ivory Coast

The Linnhoff TSD1500 MobileMix asphalt plant produced 52 000 t of hot mix asphalt for the project


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and Togo; and, in the far east, National Highway 2 (N2), its main north-south highway, which leads up to the border with Burkina Faso.

Scope of works In February 2018, work on the Tema Motorway Interchange began, transforming the roundabout into an interchange with an underpass. Also included in the scope was the construction of a 2.1 km three-lane dual carriageway with 730 m underpass on the N1, and the improvement of 1.9 km of two-lane dual carriageway on the N2. It also included the paving of five service roads and eight ramps for right-turning traffic, a 190 m long box-culvert underpass, four disabilityfriendly pedestrian bridges, traffic signals, street lighting, and other safetycritical features.

Each of the four main mobile modules of our Linnhoff TSD MobileMix asphalt plants comes with a built-in chassis, so they are much easier to mobilise as they can all be quickly dismantled and transported, as only prime movers are needed.” – Lee Yen Meng, CEO, Lintec & Linnhoff Asphalt Pte Ltd.

The Tema Motorway Interchange project is expected to ease traffic congestion and boost trade with neighbouring countries

Hot mix production The Linnhoff TSD1500 MobileMix asphalt plant consistently churned out 100 to 120 tonnes per hour (tph) of hot mix asphalt, playing a crucial role in keeping the project on track. Overall, it produced around 52 000 tonnes of hot mix asphalt for the construction of a total of 150 000 m2 of asphalt works, for use in the base, binder and wearing courses. The plant’s unique dual-function screen drum technology enables both the dr ying and screening of aggregates to be processed in the same drum, eliminating the need for a hot elevator and vibrating screens. Not only does this reduce fuel consumption and emissions,

but maintenance is easier too, reducing costly downtime.

Plant deployment and mobility All of the four main mobile modules that make up each Linnhoff TSD MobileMix asphalt batch plant are pre-assembled at the factor y, before undergoing rigorous test cycles to ensure smooth setup once they reach the jobsite. And, being equipped with a hydraulic powerpack self-jacking support system, there is no need to employ large cranes for the installation and dismantling processes, meaning plant operation can begin more quickly. By offering important advantages in terms of enhanced mobility, the Linnhoff TSD series

Work on the Tema Motorway Interchange began in February 2018 where the Linnhoff TSD1500 MobileMix asphalt plant churned out 100-120 tph of hot mix asphalt

is ideal for use in remote locations or short-term projects. After the work on Tema Interchange was completed, the plant was moved to the National Trunk Road N8 jobsite. The mobility of the plant is extremely beneficial, especially when the contractor moves on to different projects, explains Lee Yen Meng, CEO, Lintec & Linnhoff Asphalt Pte Ltd. “In Africa, renting cranes can be difficult and expensive, and then finding suitable trucks to transport the individual modules is even more costly. However, each of the four main mobile modules of our Linnhoff TSD MobileMix asphalt plants comes with a built-in chassis, so they are much easier to mobilise as they can all be quickly dismantled and transported, as only prime movers are needed,” says Lee.

Socio-economic connections According to B&FT Online, the improvements in the Tema Motor way Interchange are expected to shave 15 minutes off the 20-minute delay that motorists used to experience at the old roundabout. It will also improve the capacity, safety and efficiency of the surrounding transportation network. This high-quality road infrastructure will lead to vastly improved logistics to and from Tema Port, boosting trade with neighbouring countries. It will bring a better future for all people in the region, contributing not only to Ghana’s economic growth, but also the economic development of West Africa as a whole.

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A collapsed gabion retaining wall system caused by the recent KwaZulu-Natal floods

The vital role of


The devastating impact of extreme weather events highlights the key role of environmentally engineered structures as one of the effective countermeasures, says Louis Cheyne, managing director of Gabion Baskets. By Alastair Currie


he importance of soil retention and erosion control was underscored by the extreme floods in KwaZulu-Natal (KZN) and other parts of South Africa in April 2022. Landslides, raging stormwater and structural collapses were widespread, with properties bordering rivers among the worst affected. From an environmental perspective, the devastation highlights the impact of urban expansion, at times at the expense of natural forests and vegetated areas. “With more hard surfaced areas and greater run-off velocities, soil erosion is an ongoing issue that can slowly but surely undermine key infrastructure like buildings, walls, roads and bridges,” Cheyne explains. A specialist manufacturer and supplier of gabion systems, Gabion Baskets has extensive experience in providing expert advice and design recommendations for environmentally engineered systems. In addition to standard Class A galvanised double-twisted hexagonal mesh gabion baskets and gabion mattresses, other product solutions include woven and non-woven geotextiles, and biodegradable blankets.


IMIESA May 2022


Forming part of a bio-engineered solution, biodegradable blankets are laid out and pegged in place – commonly on steep slopes or newly constructed fills – as an affordable erosion protection system, and to reduce water run-off velocities. These blankets, which are often combined with gabion systems, can be vegetated with resilient plants that help to stabilise slopes and embankments. As these blankets degrade over time, they release nitrogen into the soil, which promotes the initial vegetation growth phase. One plant receiving increasing attention worldwide for natural soil retention is vetiver grass, which has a dense, interlocking root system that extends vertically downwards to around 3 m within two years of being planted. Fire-resistant, with exceptional tensile strength, vetiver also absorbs large amounts of water, which contributes to an overall ‘negative pore pressure’. “Another intervention is the installation of gabion mattresses to counter slope erosion, and these can also be blanketed and covered with seeded topsoil to naturally blend in,” says Cheyne.

Importance of geotextiles For any retaining wall structure, the design starts with a soil analysis. This will determine which geotextile is best suited.

The vegetated gabion mattress (centre) withstood the brunt of the storm

These are installed as an interface behind and below the gabion structure and the soil being retained. As Cheyne points out, soils are high in compressive strength, but very low in tensile strength. Add water and the pore pressure goes to 100%, so controlled drainage is crucial for structural integrity. “Where geotextiles are not employed, the migration of fine soil can cause subsidence problems, especially in sandy soils. Here a non-woven fabric is required,” Cheyne explains. “However, clayey soils do not generally require a geotextile filter fabric as these materials seldom leach through the basket section. Where installed, a woven


Concrete block retaining wall supported on a gabion foundation

geotextile is specified to allow water to pass through the gabion system and so prevent hydraulic pressure build-up.” Depending on the system design, Gabion Baskets normally recommends the installation of approximately 1-2 m² of geotextile per cubic metre of gabion.

KZN damage assessment

2 m high gabion benched wall section

ability to flex under strain respond well to hydraulic pressures and debris impact. This flexibility also means that gabion retaining walls can be safely founded on expansive clayey soils. The same is not true for a concrete block retaining wall in the same application. Placing a rigid concrete block wall directly on to this flexible soil would spell disaster, since ongoing expansion and contraction of the clay will cause any concrete foundation on which it rests to move and eventually crack.

One way of countering this is to bench out the flexible soil to a specified depth and then import rockfill material to form the compacted, cement-stabilised foundation. Another way is to adopt a hybrid approach. Typically, this comprises a gabion foundation in the riverbed resting on a geotextile layer on which the stepped-back concrete retaining block wall rests. This provides a robust solution, given that a single gabion basket can support 300 t/m2.

In response to the KZN floods, Gabion Baskets personnel from the Johannesburg factor y, together with members from its Durban office, were on-site in April to respond to enquiries from property owners and contractors for repair solutions. In many cases, banks and slopes had collapsed due to the failure of existing gabion or concrete block mass gravity retaining walls, or where there was no existing system in place. The damage was compounded in places by inadequate stormwater drainage, plus burst water and sewer lines, which contributed to wall foundation collapses. “Professional design and installation experience is essential when it comes to developing environmentally engineered Vetiver grass has become popular worldwide as a responses,” says Cheyne. “Where bioengineered response to soil erosion because wall failures have occurred, it’s of its deep and extensive root system important to investigate the underlying cause before reinstating to avoid a repeat of the problem.” River walls are particularly challenging and complex to construct. Here, gabion retaining walls perform optimally because they are designed to be submerged. Additionally, their degree of permeability – thanks to their rockfill and approximately 35% void composition – and

IMIESA May 2022



A retaining wall failure Severe landslide damage to a housing development in Kloof, KwaZulu-Natal

Flood barriers To meet future flood containment challenges, Gabion Baskets has expanded its product suite to include gabion barrier systems. These are assembled using Class A galvanised weld mesh wire panels (75 mm x 75 mm x 4 mm diameter mesh) and lined with a heavy-duty geotextile. The basic wall height is 1 m, but this can be increased to 2 m by stacking one barrier on top of the other. The major advantage of these barriers is that they’re quick to deploy by hand and can be filled with a variety of materials ranging from earth, sand and gravel to crushed rock and other granular materials. They are also

stronger than sandbags and can be filled with earthmoving plant on-site. “It has been said that one of South Africa’s largest exports is soil, and this is a sad reflection on the extent of land degradation in general,” adds Cheyne. “That’s why renewed emphasis has to be placed on sustainably engineered solutions that preser ve our ecosystems, so that human habitation and infrastructure development are in balance. The reality is that the KZN floods have shown that it’s not just about countering erosion, but catastrophic erosion going for ward,” Cheyne concludes.

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A gabion barrier system built using welded mesh and lined with a heavy-duty geotextile

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Resource management key FOR FUTURE GROWTH

Nico Pienaar, director of ASPASA

The UN, in an unprecedented announcement made recently, warned world leaders of looming sand shortages that could stunt mankind’s future development.


e now find ourselves in the position where the needs and expectations of our societies cannot be met without improved governance of sand resources. If we act now, it is still possible to avoid a sand crisis," said Sheila AggarwalKhan, director: Economy Division, UNEP. In South Africa, the situation is not that dire – yet – says Nico Pienaar, director of surface mining industry association ASPASA, who says timely interventions in recent decades have contributed to the country’s sand resources being better managed than before. The establishment of the association in the 1990s was a turning point for the sector when leaders and stakeholders took matters into their owns hands to self-regulate the industry and manage resources for future generations. Full government recognition of ASPASA in later years also led to close cooperation between the Department of Mineral Resources and Energy, members and labour. This type of cooperation has paved the way for a more sustainable sand industry. “Right now, the country has all the expertise, resources and capital funding needed to ensure the industry’s longevity, provided the scales aren’t tipped in favour

of illegal and informal operations that are sprouting around the country,” Pienaar explains. “Government and the private sector can easily ensure that they are dealing with legal and sustainable operations by simply dealing with ASPASA members who have been audited and found to follow all licensing requirements, including health, safety and environmental legislation,” he continues.

• Laurencia Maphumulo, Midmar Quarry • Donald Katiso Tsotetsi, Afrimat Qwa Qwa. Sietse van der Woude, senior executive, Minerals Council South Africa, who was a guest speaker at the event, lauded Pienaar’s and the organisation’s tireless advocacy. In recognition, Pienaar was awarded ASPASA's Top Person of the Year by his peers for his unwavering commitment to the organisation and its members.

ASPASA ISHE and Health and Safety Awards

Standing by for infrastructure roll-outs

The ASPASA 2021 ISHE and Health and Safety Awards, held in April 2022, underscores the association’s commitment to best practices. During the awards, Gert Coffee, chairperson at ASPASA, commended the organisation and its members for their achievement of zero harm incidents for six consecutive years. He reiterated that these awards are a celebration of ASPASA members’ consistency in their health and safety compliance. The ASPASA ISHE and Health and Safety Awards winners for 2021 are: - Top Performer: Afrimat Qwa Qwa - Top Independent Performer: Midmar Quarry - Top Corporate Performer: Afrimat - Health & Safety Management Awards for Outstanding Commitment: • Lucretia van Rensburg, Afrisam Western Cape • Mogamat Bailey, Afrimat Western Cape. - Health & Safety Officer:

The material mining and quarrying industry in South Africa is a strong and resilient one that directly employs nearly half a million people, and its sustainability will be further supported by renewed public sector infrastructure development. “Government wants to unlock higher levels of employment in the infrastructure sector, and we suggest it is critical to work with industry associations like ASPASA and regulatory bodies to ensure jobs created are meaningful, sustainable, safe and empower the larger communities rather than the select few,” adds Pienaar. “We want to avoid the use of roadside borrow pits and unlawful illegal sand or aggregate operations. We expect government to rather make use of compliant ASPASA members who are tax-paying, law-abiding enterprises that contribute to local and national economies,” Pienaar concludes.

IMIESA May 2022




THE BRICK Corobrik’s new R800 million Kwastina (‘Home of the Brick’) factor y is the most technologically advanced and environment friendly brick-manufacturing plant in Africa.


wastina is testament to our commitment to constantly innovate. It is an acknowledgement on our part that we need to progress and make those step changes to keep us relevant for the next 100 years,” said Nick Booth, CEO, Corobrik. Speaking at the official opening and plaque unveiling in May 2022, President Cyril Ramaphosa said the public sector and private business can come together to form productive partnerships that can accelerate South Africa’s economy and create jobs. The President hailed the local company for doing well despite the devastating and detrimental impact Covid-19 has had on the South African economy. “Much as we sought to manage Covid-19 and navigate our way around its dangerous paths, we still lost two million jobs. For an economy like ours, which was precariously positioned over a number of years, to lose two million jobs in just a 12-month period is quite a devastation,” he stated. “We are very pleased that as we begin to recover, we have companies like Corobrik who are living up to the commitments they made and are creating jobs and making sure that our economy moves forward. Corobrik is making a vital contribution – in a very literal sense – to rebuilding South Africa’s economy,” Ramaphosa added.

Fully automated Capable of producing 100 million bricks a year, the high-tech facility in Driefontein, Gauteng, is fully automated – from mixing the raw materials to the end product. In addition to meeting large-volume orders, the factory is also flexible enough to produce small quantities of bespoke products for segments that include the architectural market. “What makes this factory so exciting is that it allows us to compete anywhere in Southern Africa, landing product in regions traditionally


IMIESA May 2022

President Cyril Ramaphosa and Nick Booth, CEO, Corobrik, during a tour of the new plant

HIGH-TECH INNOVATION AT KWASTINA Dryer plant The dryer system consists of two separate tunnel dryers based on the latest advances in air circulation technology. Kiln plant The kiln system consists of two separate tunnel kilns coated with PTFE on the inside for sealing purposes. To optimise energy consumption, the kilns feature a preheated combustion air supply and systematic wheel cooling in the undercar area. The burner system with pulse control and flashing device, combined with a kiln control system, ensures an optimal firing result to produce a variety of fired products. Unloading and packaging The kiln car handling is fully automated. The tunnel kiln cars are transported to the unloading position, where finished firing packs are unloaded from the kiln car deck. The firing packs are placed carefully on a belt conveyor and delivered to the dehacking robots. Two industrial robots form a complete dispatch pack on each line and feed it to the packaging plant.

Corobrik’s R800 million Kwastina factory in Driefontein

not in Driefontein’s market, as the new factory is more cost-effective,” says Booth. “It is going to give us an advantage in the market, not just in terms of technology, but also in quality and consistency, which are critical for specifications involving tight tolerances.” Corobrik is already hard at work extending its product range, with various new products being introduced already. Current trials are being carried out with brick glazing for custom projects, as well as the clay raw material to produce different colours to give Kwastina a unique footprint in the country.

Production at Kwastina is high-tech and energy efficient


offer value AND DURABILITY


e all drive over them, complain when their lids go missing, but seldom realise the crucial role manholes play in the construction of underground pipelines. Within this field, Rocla is a market leader, designing and manufacturing standard and customised systems. Placed at regular inter vals along the pipeline, used as a junction where stormwater pipes meet up, or where stormwater flow needs to be redirected, as well as for ventilation along sewerage systems, precast concrete manholes are still the preferred choice for infrastructure projects due to their durability (lasting up to 100 years). Assembled at site, they are quick and easy to install. Rocla’s precast concrete manhole with an interlocking joint profile, together with the application of a sealing material, makes for a simple yet effective solution. The manhole chamber sections are supplied in lengths of 1 000 mm, 500 mm and 250 mm, and are available in diameters of 750 mm, 1 000 mm, 1 250 mm, 1 500 mm, 1 800 mm and 1 950 mm. Special intermediate or larger sizes can also be designed and manufactured subject to a feasibility study, and Rocla engineers can assist in this evaluation process. Step irons can be cast into the wall of the chamber, while concrete lids are also offered as an alternative to the conventional cast-iron option.





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Precast concrete manholes provide a working chamber for easy and cost-efficient access for technicians and their equipment during routine inspection and maintenance

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The new and definitive

Terraforce Design Guide

The beautifully curved Terraforce block wall at the Salamanca Hospital development in Spain


plit into two sections, the Terraforce Design Guide deals with the theory and practice of gravity retaining wall design – with worked examples – as well as the design and installation of Terraforce reinforced soil retaining walls in accordance with BS 8006 and SANS 207:2011. All the procedural and sequential steps that need to be followed are covered to construct safe and sound SRW structures. “Minimum requirements in the standards (SANS 207 and BS 8006) are sometimes questioned by engineers, such as the seemingly excessive minimum width of the reinforced soil structure. The reason for this is explained in depth, with guidance further provided for specifying shear resisting mechanisms,” says industry pioneer Holger Rust, founder of Terraforce, adding that another important topic covered includes the SANS 10400 National Building Regulations regarding balustrading above walls that exceed 1 m in height.


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“As with any structure, the design of Terraforce retaining walls should only be undertaken by suitably qualified and experienced designers with due cognisance being taken of the specific geotechnical conditions and vital soil parameters pertaining to the site,” Rust explains. The Terraforce Design Guide also has builtin links to useful tools to assist in design, construction and supervision routines. Cautionary notes and notes for contractors are included, as well as a Table Creator to obtain design values for Terraforce’s range of precast concrete retaining wall blocks and allied products, and to help in estimating material costs. “There will be a link to the Maxiwall Pro software for the design of composite retaining walls, as well as a link to Terrasafe, our in-house design ser vice,” says Rust, adding that users can access the Design Guide by registering online at

Partially based on the company’s original 1992 design manual, Terraforce’s new extended version involved the participation of professionals in three countries and takes note of their unique challenges and experiences in the design of segmental retaining walls (SRWs) in accordance with local and international standards.

Maxiwall Pro Terraforce launched Maxiwall Pro in August 2018 as a privately labelled version of the most comprehensive and widely used SRW design software in the industry, the Vespa MSE Design Suite (updated to the latest standards in 2020). Maxiwall Pro allows SRW design professionals to easily produce complete wall designs utilising the award-winning Terraforce line of SRW products. With all block and geogrid information preloaded, designers can select from a wide range of proven Terraforce systems via easy-to-navigate drop-down menus. Compared to other mechanically stabilised design software options, Maxiwall Pro increases design efficiency, improves accuracy and promotes a seamless flow of information between design stages and parties. It generates full wall layouts with accurate quantity estimates and comprehensive reports. The Calculation Engine can simultaneously run static, seismic and ICS analysis in accordance with NCMA,



A light gravity staggered SRW wall design

A reinforced staggered SRW wall design using Terraforce Rock Face blocks

AASHTO (LRFD), AU (Australian Standard), and British Standards design methodologies. “The Terraforce package is built around the understanding that the goal of the design engineer is to produce a set of clear, comprehensive construction drawings. With the DXF output feature, CAD cross sections and elevation views are automatically generated and ready to import into AutoCAD. “Users of the Maxiwall Pro package will also have an option to purchase a copy of the AWall CAD Tool, which allows the user to accurately represent the plan and elevation views of a retaining wall Simple, easy-to-follow design tutorials are on their grading plan,” Rust explains. provided. These cover the generic version of AWall factors in the variable heights along the Vespa MSE Design Software, but generally length of a wall, wall batter (inclination), and apply to Terraforce SRW. wall width to generate a plan view, representing “The Terraforce Design Guide is our the ‘real’ footprint of the wall, and can create contribution to setting the benchmark for elevations and generate quantities. SRW excellence both in South Africa as “Once the design is complete, Maxiwall Pro well as internationally where our Terraforce also allows you to export the wall geometry, products are employed, and a special soil conditions and loading conditions to thanks goes to the various authors for select Global Stability software their invaluable input in updating the 1992 Phase 3programs,” settling tanks in operation Rust continues. version,” Rust concludes.

The practice of building retaining walls and barriers for various purposes, such as level platforms, dams and stabilised slopes, has been pursued on all continents for at least 6 000 years. Traditionally, rough or shaped boulders, rock-filled wicker baskets or clay mixed with reinforcing straw were used. Early on, advances were made with burnt clay bricks, and then around 2 000 years ago with the invention of concrete by the Romans. With the demise of this empire, the know-how to make concrete was lost until its reinvention in the early 1800s in the UK by Joseph Asplin, inventor of Portland cement. From the 1850s, mass concrete, in combination with reinforcing steel, became the preferred choice of material for building retaining walls. The first machine designed to manufacture hollow concrete retaining blocks was produced by a concrete pipe manufacturer in Germany. Since then, many concrete retaining block designs have been developed to build segmental retaining wall systems. Some are interlinked with gaps between blocks, while others interlock on the vertical and/or horizontal plane. All systems rely – when used for mass gravity retaining walls – primarily on constructed mass (block weight and weight of soil, gravel or concrete contained within the blocks) and on inter-block friction to derive a measure of sliding resistance and, to a lesser degree, on interlinking or interlocking between blocks.

Soil reinforcement The concept of soil reinforcement was recognised more than 5 000 years ago. For example, ancient civilisations used straw and hay to reinforce mud blocks to create reinforced building blocks. The Great Wall of China serves as one of the earliest examples of reinforced earth using tree branches as tensile elements. Woven geotextiles Woven geotextiles came into existence in the early 1960s (Huesker Synthetic). The modern form of soil reinforcement was first applied by Vidal (1969). Geotextile reinforced retaining walls with wraparound facing were first built in France. Due to limitations on the design life of the wraparound geotextile facing, segmented retaining block walls were later used for this purpose.

IMIESA May 2022



Consider LOW-VOLUME concrete roads for EXTREME WEATHER conditions

Experience has shown that inadequate drainage is probably responsible for more road damage in Southern Africa than inadequate structural or material design

With extreme climatic conditions likely to become a regular future occurrence, local and national government should more seriously consider low-volume concrete roads with effective drainage to help protect the country’s transport network, says Bryan Perrie.


IMIESA May 2022


errie says jointed in situ (poured in place) concrete can be used to construct economical and durable rural low-volume roads designed to handle speeds of up to 90 km/h in unpopulated areas and up to 60 km/h in rural areas as well as city housing settlements. He believes economy, ease of construction and maintenance considerations make unreinforced jointed concrete pavements (JCP) ideal for low-volume roads. “In jointed low-volume roads, load transfer by aggregate interlock is generally adequate. When close joint spacings are used, reinforcing steel is not needed but reinforcing mesh should be used in odd-shaped panels and for manholes and other openings,” he explains. Joints are provided in concrete pavements to: • limit stresses and control cracking resulting from restrained contraction and the effects of restrained warping and traffic loads • facilitate construction and level control • accommodate movements of the road surfaces. “Joints must provide adequate load transfer to ensure adequate performance of the pavement. This can be achieved using sawn construction joints at relatively close spacings and keyways at construction joints,” he explains.

Correct material specification Perrie says the correct choice of materials is vital for the construction of durable low-volume concrete roads. Cement should be CEM I or CEM Il A 42.5 or higher complying with the requirements of SANS 50197. Where extenders (ground granulated blast furnace slag or fly ash) are used, these should comply with the requirements of SANS 50450 and SANS 55167. When extenders are used, allowances should be made in the concrete mix design, particularly regarding early strength under field conditions to ensure the timeous cutting of joints. Curing methods and regimes may also have to be improved, especially in inclement weather.

Sand and aggregates Bryan Perrie, CEO, Cement & Concrete SA

Satisfactory aggregates for use in lowvolume concrete roads and streets are those that comply generally with SANS 1083 Aggregates for Concrete. In addition, the fine aggregate should possess an acid insolubility of at least 40% for skid


resistance. This requirement is satisfied when quartzose sand is used. Calcareous sands, such as dolomite, are acceptable if blended with at least 40% of a suitable quartzose sand. Perrie says the mixing should be done with clean potable water or other water free of substances that may impair the strength, setting time or durability of the concrete, or the strength and durability of any reinforcement.

“The concrete should be strong enough to ensure a hard, durable, skid-resistant surface and to accommodate the tensile stresses resulting from shrinkage, warping and loading. This requirement is satisfied by specifying a target flexural strength or modulus of rupture of not less than 4.5 MPa at 28 days. The mixes for use in concrete roads should be designed by an approved concrete testing laboratory or CCSA should be approached for advice on materials and mix proportions,” Perrie explains.

Admixtures Under certain circumstances, the properties of the concrete may be improved by the proper use of chemical admixtures, such as water-reducing admixtures. Their use should be based on an evaluation of their effects on specific materials and combinations of materials, including strength development, particularly within the first 24 hours after concrete placing. This is because certain admixtures may retard the setting and strength development of the concrete, thus delaying joint sawing and increasing the risk of random cracking.


he rehabilitation of dam walls usually requires the demolition of redundant portions of monolithic blocks and associated concrete structures. However, the dynamic energy imparted by the demolition process has the potential to cause damage to concrete located just across the demolition boundaries and beyond. For this reason, expert techniques are required to achieve a safe and cost-effective result, as showcased on the Hazelmere Dam rehabilitation project carried out by Jet Demolition. Here, a combination of explosive, mechanical and diamond-cutting methods were employed. “Our work at Hazelmere Dam allowed for the compilation of specific demolitioncontrol guidelines to be developed for dam rehabilitation projects,” explains Kate Bester, contracts manager, Jet Demolition.

Piano key weir conversion Located on the Mdloti River in KwaZulu-Natal, the Hazelmere Dam was built in the 1970s. It was designed originally to accept radial arm gates to raise the full supply level (FSL). However, a subsequent redesign showed that

Drainage Proper drainage is also essential to prolong the lifespan of low-volume concrete pavements. Experience has shown that inadequate drainage is probably responsible for more road damage in Southern Africa than inadequate structural or material design. The design philosophy is to provide effective drainage so that the pavement structure is prevented from becoming saturated. Both the discharge of surface run-off and the control of subsurface water

need to be considered. Consequently, effective drainage is essential for good pavement performance, and is assumed in structural design. “Sur face run-off can be controlled in the rural environment by constructing sufficiently wide side drains that discharge at sufficiently frequent inter vals into the adjacent land, or into culverts that carr y the water to suitable discharge points,” says Perrie. “In the urban environment, it can be controlled with the use of kerb and channel systems discharging into inlets into a stormwater pipe system. To reduce costs for low-volume roads, consideration should be given to dishing the road sur face and carr ying the stormwater on the road sur face to suitable discharge points,” Perrie concludes. A detailed CCSA publication, Low-volume Concrete Roads, is available as a free download from the Cement & Concrete SA website – – or phone +27 (0)11 315 0300 for more information.

Perfecting the art of dam wall rehabilitation the FSL would be achieved optimally via a piano key weir. To clear the way for new construction works, demolition of the existing spillway crest, piers, lintel beam and bridge decks required the controlled removal of 5 300 m3 of concrete up to 3 m in thickness. The key requirements were to demolish the redundant structures in a safe, rapid, cost-effective and controlled manner, without residual damage. The traditional demolition method for projects with large volumes of mass concrete is explosives, with large hydraulic hammers used for the smaller concrete sections and for secondary breakage. Finishing work is typically undertaken by small hydraulic hammers and handheld breakers. When considering safe blasting vibration levels for a particular project, it is critical to consider the prevailing site conditions and geometrical configurations. “At Hazelmere Dam, our production blasting programme and demolition methods achieved all of these objectives successfully,” Bester concludes.

Jet Demolition has developed new blasting techniques to retain the structural stability of dams during rehabilitation projects Mechanical demolition in progress during the rehabilitation of the Hazelmere Dam wall, which was redesigned to incorporate a piano key weir

IMIESA May 2022



Flooring refurbishment at the SAAO The Southern African Large Telescope is the largest single optical telescope in the southern hemisphere

Flooring refurbishment operations in progress

A section of the restored floor


he Southern African Large Telescope (SALT) is the largest single optical telescope in the southern hemisphere. It is situated at the South African Astronomical Observatory (SAAO) field station, near Sutherland in the Northern Cape. Funded by a consortium of local and international partners, SALT has been in full scientific operation since 2011 – Africa’s giant eye in the sky. Even as SALT scientists look up, what lies beneath their feet is as important. The SAAO needed a complete floor refurbishment in the 120 m2 instrument room and appointed Eyethu Alpha as the main contractor. Botwei Projects, a Sika-approved applicator, was then appointed by Eyethu Alpha as a specialist contractor for the Sikafloor systems. The refurbishment process started with the floor preparation, which was done using the cup grinding method. This exposed the problem areas of the floor, which determined the repair process and product requirements. All cracks in the floor were exposed and cleaned,

and thereafter, gravity fed with Sikadur-52 ZA epoxy resin. Used to fill and seal voids and cracks in structures such as bridges and other civil engineering buildings, Sikadur-52 ZA is a two-part, low-viscosity, multipurpose epoxy resin, which has excellent penetration and high bond strength. Following a good cleaning and a wipe with an oil-free solvent, the floors were then primed using Sikafloor-161. Thereafter, an inspection was conducted to locate any pinholes, which were subsequently closed with Sikadur-31 DW epoxy. This is a two-part, epoxy-based, moisture-tolerant structural adhesive that bonds most construction materials, has high mechanical strengths, and can also be used for minor concrete repairs, joint filling and crack sealing. It has been specially formulated to meet the requirements for use in contact with drinking water.

Self-smoothing epoxy floor screed A final 2 mm thick layer of Sikafloor-263 SL epoxy floor screed was then applied. This

self-smoothing epoxy solution is for concrete and cement screed with medium to heavy traffic. It is highly durable and applied by a Sika-approved specialist applicator. After curing, the existing floor joints were cut, reemed and then primed with Sika Primer-3N. This is a solvent-based primer designed for use prior to other Sika products, on porous substrates such as concrete. It is also easy to apply, has a short flash-off time and is water-repellent. The joints were then sealed using Sikaflex PRO-3, a high-performance polyurethane sealant designed for floor joints and various other civil engineering applications. It is a single-component, moisture-curing, elastic sealant with high mechanical and chemical resistance. It cures without bubbles and is solvent-free. Eyethu Alpha and Botwei Projects successfully refurbished the floor, and the project was completed in December 2021. Together with Sika products, these contractors reached for the stars to provide a result that was simply a beautiful floor, but out of this world.

IMIESA May 2022




A large agitator with sharp knives ploughs its way through the mass in the storage silo for alternative fuels


ement manufacturing is highly energy intensive because of the extreme heat required to produce it. However, by using alternative fuels and raw materials (AFR), the production process becomes more economical, primar y raw materials and fuel resources are conser ved, and landfill volumes are reduced.

AFRs AFRs consist of whole and shredded tyres, waste timber or mixtures of plastics, paper, compound materials or textiles whereby their calorific value hardly differs from that of lignite (brown coal). The value of old tyres is even comparable with coal. But the use of these alternative fuels has pitfalls. They must be processed prior to use in such a way that they do not influence the later production process and the quality of the cement.


A radar level measuring instrument that performs in challenging conditions. transmitters, capacitive measuring instruments and vibration limit switches) for over a decade. Cementos Molins needed a solution for the storage silo that contained AFR. With a height of more than 20 m and a diameter of 9 m, the storage silo has an unusual agitator on the inside floor of the silo, which consists of very sharp, vibrating knives to grind the waste continuously. About 35% of the fuel in the plant that is required for the later production of cement comes from alternative fuels. About one tonne of AFR material is unloaded into the silo per hour. The trucks loaded with waste must be completely emptied so the capacity in the silo must therefore be sufficiently great to hold a complete truck load. Level measurement provides protection against the threat of over filling and being empty.

Cementos Molins

Challenges with measurement when filling the silo

The Barcelona subsidiary of construction materials company Cementos Molins has used a range of Vega sensors (pressure

AFR materials stick very easily. Furthermore, when filling the silo from the trucks, a cloud of dust forms – creating heavy deposits on the

IMIESA May 2022

sensor and making measurement extremely difficult. During simultaneous stirring and chopping, a 2 m high wave of material is pushed along in front of the agitator blades. The stirring itself also generates a cloud of dust in the container that never settles due to the vibrations. This dust influences the technology and measurements. The previously installed 26 GHz radar sensor with horn antenna from another manufacturer created many issues. The dust stuck to the horn antenna and caused false measured values. The constant vibrations caused by the cloud of dust made reliable signals possible. Furthermore, the metal particles from the Tetrapaks in the silo also caused false signals in the sensor. Metal particles from Tetrapaks can create interference signals due to flying metal foils.

VegaPuls 69 Vega’s 80 Ghz radar level measuring instrument promises a much more reliable operation because of the higher focusing of the medium. At that time, a few test measurements had already been made in comparably difficult measuring situations. It


succeeded in also measuring media with poor reflection properties more accurately and easily. The high focusing also helps better differentiation of the actual measuring signal from the interference signal in containers with a lot of installations. With a measuring range of up to 120 m at an accuracy of ±5 mm, there are enough power reserves even for unusual applications. These seemed to be ideal conditions for the difficult measuring environment. One also has to know that the opening angle of the radiated radar energy and the focusing therefore depends on two factors: the transmission frequency and the active antenna area. As a result, much better focusing is achieved with a higher frequency and identical antenna size. The VegaPuls 69 operates with a transmission frequency of 80 GHz and an antenna size of around 75 mm. This achieves an opening angle of only 3 degrees. In a radar sensor with 26 GHz transmission frequency, the opening angle at the same antenna size is about 10 degrees. The 80 GHz beam also goes past installations or deposits on the container wall. This makes the measurement safer and more reliable. The measuring instrument itself is made from the robust PEEK material, which has a high temperature and chemical resistance. The lens antenna is also insensitive to deposits and dirt, and shows no signs of wear. To simplify commissioning, an intelligent swivel holder was also developed with the

aid of which the sensor can be aligned quickly, easily and optimally. To get the optimum angle of tilt for the installation of the measuring device, a smartphone is simply placed on the device so that the sensor can be aligned quickly and optimally with an app.

No loss of transmission signal The Vegapuls 69 radar sensor has ver y good signal focusing and a high dynamic range. The 80 GHz penetrates the dense cloud of dust. Since the sensor has a purging air connection as standard, this can be cleaned quickly at any time so that any deposits ‘deal with themselves’. Despite the inter ference signals that could not be totally avoided due to the surrounding metal particles, an almost exact level measurement is achieved. A remote display is located prominently at eye level on the silo to avoid the ser vice team having to climb on to the silo during maintenance. It gives the ser vice team an over view of all the data at all times.

The fuels must be processed before firing so that the processes run uniformly later and the same calorific value is consistently achieved

The trucks deliver the alternative fuels to the cement factory around the clock

IMIESA May 2022




AECOM AFI Consult Alake Consulting Engineers ARRB Systems Asla Construction (Pty) Ltd BMK Group Bosch Projects (Pty) Ltd BVI Consulting Engineers CCG / Corrosion Institute of Southern Africa Dlamindlovu Consulting Engineers & Project Managers EFG Engineers Elster Kent Metering EMS Solutions ERWAT GIBB GIGSA GLS Consulting Gorman Rupp Gudunkomo Investments & Consulting Hatch Africa (Pty) Ltd HB Glass Filter Media Herrenknecht Huber Technology Hydro-comp Enterprises Infrachamps Consulting INFRATEC IQHINA Consulting Engineers & Project Managers iX engineers (Pty) Ltd JBFE Consulting (Pty) Ltd JG Afrika KABE Consulting Engineers Kago Consulting Engineers Kantey & Templer (K&T) Consulting Engineers Kitso Botlhale Consulting Engineers KSB Pumps and Valves (Pty) Ltd KUREMA Engineering (Pty) Ltd Lektratek Water Makhaotse Narasimulu & Associates Malani Padayachee & Associates (Pty) Ltd Maragela Consulting Engineers Mariswe (Pty) Ltd Martin & East M & C Consulting Engineers (Pty) Ltd Mhiduve Much Asphalt Mvubu Consulting & Project Managers Nyeleti Consulting Odour Engineering Systems Prociv Consulting & Projects Management Rainbow Reservoirs Re-Solve Consulting (Pty) Ltd Ribicon Consulting Group (Pty) Ltd Royal HaskoningDHV SABITA SAFRIPOL SAGI SALGA SAPPMA / SARF SBS Water Systems Sembcorp Siza Water Silulumanzi SiVEST SA Sizabantu Piping Systems (Pty) Ltd Sky High Consulting Engineers (Pty) Ltd SKYV Consulting Engineers (Pty) Ltd Smartlock SMEC Southern African Society for Trenchless Technology SRK Consulting Star Of Life Emergency Trading CC Syntell TECROVEER (Pty) Ltd TPA Consulting V3 Consulting Engineers (Pty) Ltd VIP Consulting Engineers VNA Water Institute of Southern Africa Wam Technology CC Wilo South Africa WRCON WRP WSP Group Africa Zutari


WALK-BEHIND ROLLER upgrade sets new standard


ne of the South Africa’s largest suppliers of compaction machines, ELB Equipment, has released a redesigned model of the ever popular and versatile Ammann ARW 65 walk-behind roller. The updated Ammann ARW 65 provides two-in-one capabilities that make it the perfect fit for every construction company. The dual-amplitude machines are favourites due to their ability to switch from high-amplitude settings for soils and aggregates, to lower amplitudes for asphalt and bituminous materials. “While maintaining its core functions, with optimum compaction power and climbing ability, the redesign on the Ammann ARW 65 includes further improvements on the ergonomics, including an improved handle with soft controls and an automatic parking brake, which prevents the machine from rolling away,” says Keon Kardolus, sales manager: Earthmoving and Construction, ELB Equipment. “Additionally, there’s the height-adjustable guide handle, which optimises operating comfort for operators of any height. The machine now also has a maximum reversing speed that has been reduced to 2.5 km/h, which enables controlled working in reverse mode,” Kardolus continues.

A multitasker He adds that the machine’s vibratory system allows for maximum compaction on various applications such as earthworks and asphalt, construction and repair of sidewalks, cycle paths, sports grounds, agricultural and forest access roads. The Ammann ARW 65’s compact design means that it can also be used in confined spaces while still offering maximum productivity. Benefits of the improved design can further be categorised under productivity and serviceability. The machine is fully hydraulic, which enables precise speed adjustment. It also allows for good side clearance, enabling precise working next to walls and kerbs, as well as an integrated sprinkler system that prevents asphalt from caking on the drums. In addition to ELB Equipment’s comprehensive aftermarket service to all its clients across South Africa, the Ammann ARW 65 has simplified maintenance requirements for daily maintenance and does not require special tools. The machine can be driven without wear parts – the fully hydraulic drive system works without a high-maintenance centrifugal clutch and V-belt.

CAREFULLY CONSIDERED IMPROVEMENTS •A new water-level indicator that is more visible • Expanded display • T he water sprinkling system on/off switch has also been repositioned within easy reach during operation •B umpers that extend beyond the machine frame for extra protection have been added • Enhanced ruggedness • I mprovements on the safety switch, ensuring the machine switches off immediately when necessary (dead man’s switch) •D esign ensures that components are discreetly housed to avoid damage • L ED lights and outlets are available as optional extras for a telematics control unit – the hardware is essential for tools such as Ammann ServiceLink IMIESA May 2022



Advantages of

reduced-temperature asphalt


he production of reducedtemperature asphalt – also known as low-temperature, warm or warm-mix asphalt – is nothing new. The process was already tested back in the 1990s. However, its application is receiving renewed attention as a proactive response to lowering greenhouse gas emissions. In this respect, Benninghoven’s asphalt mixing plants are playing a key role in rolling out this technology. A key benefit is that reduced-temperature mixtures can be conveniently produced and processed in the conventional manner. The major differentiator is that reducedtemperature asphalt is produced at a temperature of between 110˚C and 130˚C. Hot asphalt, on the other hand, is typically produced at between 140˚C and 180˚C – usually with bitumen at 160˚C as a binder.

Reduced-temperature asphalt can be retrofitted to any asphalt mixing plant using Benninghoven’s Plug & Work principle – via the foam bitumen module or solid/liquid additive feed systems

Reducing the bitumen viscosity Bitumen requires a temperature of at least around 140˚C to achieve good wetting and coating of the aggregates in the mixer. Below this temperature, it remains too viscous.Therefore, to lower the temperature during reduced-temperature asphalt production, the bitumen viscosity must be lowered temporarily. This is achieved by adding water (foam bitumen) or additives. When the hot bitumen is mixed with water, the bitumen foams and the volume increases many times over. The increased surface area enables better wetting of the aggregates in the mixer. This means that the mineral is well coated, even at a lower temperature.

High potential for saving energy and CO2

According to the German Asphalt Association, a temperature reduction of just 30˚C results in a saving of 0.9 ℓ of heating oil (or a fuel equivalent) per tonne of finished asphalt. With a daily production of 2 000 t of mixture, this corresponds to a saving of 1 800 ℓ of oil – or up to three quarters of the annual heating energy consumption of a home. The reduction in CO2 emissions is 6 000 kg per day, making reduced-temperature asphalt a highly viable and greener alternative.


Afrisam South Africa Cement and Concrete SA DataBuild IMESA Lintec and Linnhoff Holdings


IMIESA May 2022

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MODULAR ASPHALT SOLUTIONS Linnhoff was established in Germany in 1919. Apart from being one of the oldest names in the industry, it is also a leading brand of asphalt mixing plants. Word of our quality and reliability has spread as far and wide as the roads paved by the hot mix asphalt produced with Linnhoff asphalt mixing plants over the last century.