PASS Booklet | 2023

2023 PROBLEM ACCEPTED SOLUTION SUPPLIED (PASS) BOOKLET

An award providing opportunity for water industry operational staff to share their in the field innovations & fixes to problems so that others in the water industry can benefit.

SPONSORED BY

PREVIOUS WINNERS

Michael Cartmer, Quinton Caird, Martin Zardins, Stephen Casey & Michael Dixon

Matt Holz

Craig Woodhouse

Scott Kitwood

Toby Spark

Marcus Boyd

Daren Lord

Frank Rinaldo

ABOUT THE AWARD

Objectives of the Award

• To create an opportunity which encourages water industry operational staff to share their in-the-field innovations and/or fixes to problems so that others in the water industry can benefit.

• To provide an application process which is easy to complete and utilises a standard template. This will give all water industry operational staff the same opportunity for presenting their innovation.

To provide the opportunity for operational staff to receive recognition for their innovation and efforts.

• To encourage operational staff to become aware of and involved with the Water Industry Operators Association of Australia (WIOA).

To allow WIOA to share the good ideas and innovations with other Members through the Operator magazine and/or other publications.

The Process

The PASS application template and more details on the Award can be found on the WIOA website wioa.org.au/awards/national-awards/pass-award/ or from the WIOA office.

Judging

All PASS applications received in the 12 month period ending 1st March annually, will be assessed by an independent panel on a number of criteria, including:

• Commonality of the problem

Benefit to OH&S, water quality, and the environment

Financial and sustainability benefits

Application to other industries

• Uniqueness, adaptability and simplicity

Reward

The person who submits the PASS application deemed best in that particular year will be announced the winner of the PASS Award at the WIOA NSW Conference. Aqualift will provide sponsorship of $2,500 for the winner to join the WIOA team on their annual operational tour of New Zealand including attendance at the New Zealand WIOG operations conference.

2023 PASS Winner Sean Doyle, Barwon Water for his entry Shining a Light on Saving Backwash Water.

SHINING A LIGHT ON SAVING BACKWASH WATER

Sean Doyle, Barwon Water THE

The Problem

PROBLEM

What was the problem that you experienced?

What was the problem that you experienced?

Determining the exact time to stop a backwash of Lorne’s Dissolved Air Floatation Filtration (DAFF) Water Treatment Plant (WTP) has always been challenging. If stopped too soon the media will be left spoiled and reduce the next filter run time. If let run too long can waste this precious resource (230L/s) and prolong the ripening period of the filter media. Every second counts!

How did the problem impact you or your work situation?

Determining the exact time to stop a backwash of Lorne’s Dissolved Air Floatation Filtration (DAFF) Water Treatment Plant (WTP) has always been challenging. If stopped too soon the media will be left spoiled and reduce the next filter run time. If let run too long can waste this precious resource (230L/s) and prolong the ripening period of the filter media.

Every second counts!

After a rain event Lorne’s raw water quality can be very erratic causing varied filter performance which effects the backwashing length required.

A Backwash from start to finish

Probe type turbidity analysers were trialled in varied positions within the filter area but could not provide a stable accurate reading.

Previously, backwash samples were taken from the launder every 10 seconds and then later analysed to determine the time required to ensure a properly cleaned filter media. This timeconsuming exercise worked well if the raw water quality remained stable.

How did the problem impact you or your work situation?

How long had the problem been occurring?

Since commissioning of the WTP, operators would prefer to overrun the backwash to avoid an early fouled filter.

The Solution

After a rain event Lorne’s raw water quality can be very erratic causing varied filter performance which effects the backwashing length required. Probe type turbidity analysers were trialled in varied positions within the filter area but could not provide a stable accurate reading.

How long had the problem been occurring?

Suggest improvements, if time or financial Further improvements could include gallery to also determine filter bed fluidisation. Trialling different light spectrums to Adding a camera to be able to remotely

How did you come up with the solution?

Previously, backwash samples were taken from the launder every 10 seconds and then later analysed to determine the time required to ensure a properly cleaned filter media. This timeconsuming exercise worked well if the raw water quality remained stable.

Since commissioning of the WTP, operators would prefer to overrun the backwash to avoid an early fouled filter.

Any other comments you would like The collaboration between departments light. From the possibility to program from our qualified electrical team being

Rays of sunlight streaming through the window on a sunny spring day water which helped me to determine when the water had cleared enough backwash. An underwater dock light would provide a similar light source on at any time of the day or night.

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Backwashing Filter - Lorne WTP

Backwashing Filter - Lorne WTP

THE SOLUTION

How did you come up with the solution?

Rays of sunlight streaming through the window on a sunny spring day illuminated the backwash water which helped me to determine when the water had cleared enough to stop the backwash. An underwater dock light would provide a similar light source that could be turned on at any time of the day or night.

Who helped work on the solution?

Assistance was provided by fellow Coastal Treatment team operators, and Barwon Asset Solutions electrical team who completed the required electrical works. Our Technical Service team programmed the light to turn on during the backwash sequence.

Describe the solution.

Installing an underwater marina dock light into the backwash launder of the filter has allowed the operator to observe in real time when the backwash water quality was clear and, in a way, become the turbidity and colour analyser themselves.

How has it helped you at work?

The installation of a light in the backwash launder allows the operator to make a qualitative assessment that the backwash water and filter media are at a stage to be able to stop the backwash. This improvement has reduced the backwash

run time by up to 250 seconds saving 55kL per backwash. Conducting a backwash on average 60 times a year (58 in the past 12 months) equals a saving of up to 3.3ML per year. This water saving initiative has contributed to a shift in the timeframe for when we will be required to augment the Lorne water supply system to meet demand. This initiative directly aligns with our Barwon Water 2030 strategy key objective of “maintaining our efforts to continually optimise our system, so that we can make best use of available water resources and entitlements.”

Suggest improvements, if time or financial limitations were not a factor.

Further improvements could include adding multiple lights at certain positions in the filter gallery to also determine filter bed fluidisation.

Trialling different light spectrums to suit high turbidity and coloured water. Adding a camera to be able to remotely assess water quality (installed)

Any other comments you would like to make?

The collaboration between departments was very important to the successful install of the light. From the possibility to program the operation of the light source to the safe instillation from our qualified electrical team being assisted by our operations staff in a restricted space.

POO-BOAT

Celia Brown, Icon Water

THE PROBLEM

What was the problem that you experienced?

Inspecting major trunk sewers involves expensive shutdowns, night work teams and risks to safety of personnel involved. Sometimes, access to the sewer is dangerous due to the condition of access equipment such as ladders and MHs. A CCTV was organised to inspect a section of 1.7 x 1.2 m oviform sewer with historic corrosion issues. The inspection was unsuccessful as the traditional sewer camera tractor got stuck on debris at the base of the sewer. An alternative solution was required that did not place staff at risk by placing them in a live sewer untethered.

How did the problem impact you or your work situation?

Now knowing the extent of developing corrosion issues in difficult to access areas was a big concern for the integrity of our assets, which may be affecting flow capacity and may be leading to a catastrophic failure. Assessing whether expensive and risky traverses would be worthwhile was also seen as a more cost effective way of inspecting trunk sewer mains.

How long had the problem been occurring?

The problem with safely and efficiently inspecting trunk sewers has been occurring since the construction of sewers and recognition of the risks involved with sending people into a sewer of potentially unknown condition with increased regulation on overflows in case of a collapse or accidental overflow due to flow isolation measures.

THE SOLUTION

How did you come up with the solution?

In consultation with Sydney Water’s Poo-Ball team and SASTTI’s condition assessment advisory Icon Water were advised to construct a suitably sized floating sewer camera.

Who

helped

work on the solution?

Steve Barclay – Sydney Water for the Poo-Ball idea Joe Lewis, Arnold Keizer, Stephen Finch, Aiden Foord, Andrew Sharp and Marco Bottari from Icon Water for ensuring the launch was done safely.

Describe the solution.

The Poo-Boat is a cheap to make floating sewer camera utilising a GoPro 360 degree camera, 4 waterproof camping lights on a vessel made from expanding foam and rubber paint on a marine ply and threaded rod frame with a weighted ballast. The initial launch was tethered from the upstream end by 250 m of washing line cable on a hose reel due to the unknown nature of the sewer to be inspected and history of issues the boat. The boat has no motor and floats using the natural flow of the sewer. There is potential to launch the float through sewers untethered but a net or other catching method would be required.

How has it helped you at work?

This has helped Icon Water to have an initial inspection, confirming a necessary repair was required to that section of the sewer, and allowed a repair method to be established. This camera meant we inspected 500 m of the sewer in 5 hours using all internal staff with no shutdowns or night shifts while still achieving the same goals as much more labour and cost intensive methods. The next step will be to trial the camera unattached.

Suggest improvements, if time or financial limitations were not a factor.

Improvements to be made to the prototype include moving the lights to below the eye level of the camera as they get in the way as well as a small rudder to reduce spinning. Knowledge

of any assets which may prevent the float from moving is necessary, such as drops or air curtains.

Keeping the camera and lights detachable means we can design several vessels to inspect sewers of different sizes. For unattached inspections, it is recommended to send a ‘canary’ float ahead such as a football or foam boat with no camera to ensure the path is clear as you can not see the screen while it is in the sewer. Chainage can be estimated by known distance between MHs and travel time.

Any other comments you would like to make?

Thank you for others in the industry sharing their knowledge and ideas to enable this to happen. I recommend trialling this in sewers of known good condition, and while attached for retrieval before embarking on larger voyages.

See a clip of the footage quality here, you can change to 4K (in settings) and scroll around as it floats or pause to look around: https://youtu.be/fRRBNQdI81w

The Problem

What was the problem that you experienced?

The Bray Park Water Treatment Plant treats raw water from the Tweed River pathogens harmful to human health and meeting operational water-quality the safe and reliable delivery of drinking water to customers throughout the

CO2 WORKAROUND WITH TEMPORARY DOSING OF LIME

Brie Jowett, Tweed Shire Council

THE PROBLEM

What was the problem that you experienced?

The Bray Park Water Treatment Plant treats raw water from the Tweed River by removing pathogens harmful to human health and meeting operational water-quality targets, ensuring the safe and reliable delivery of drinking water to customers throughout the Tweed.

One of the treatment processes includes the use of carbon dioxide (CO2) gas injected as a side stream into raw water to control the pH and stability of the final, treated water. This process allows effective membrane ultrafiltration (including the effective removal of pathogens) and creates drinking water that will not dissolve the concrete and other compounds found inside distribution water mains and network reservoirs. The need to dose CO2 is most important during heavy rainfall events including floods when the alkalinity and calcium hardness of the water must be raised using lime. CO2 is critical for lowering the pH down to required levels.

In 2022 immediately after the biggest flood event yet recorded in the Tweed, Council lost its CO2 supplier. The supplier, sighting force majeure under the contract, could not supply our treatment plant with CO2 due to the short supply and high demand of this chemical (particularly due to the food and beverage industry).

How did the problem impact you or your work situation?

It was unfortunate when Council’s supplier of CO2 delivered this news because the chemical is very important to the overall water treatment process and our raw water quality after the flood required higher amounts of CO2 dosing. We needed to come up with a solution to manage our treatment processes to ensure we could continue to produce safe drinking water.

One of the treatment processes includes the use of carbon dioxide (CO2) gas stream into raw water to control the pH and stability of the final, treated water. allows effective membrane ultrafiltration (including the effective removal of creates drinking water that will not dissolve the concrete and other compounds distribution water mains and network reservoirs. The need to dose CO2 is most during heavy rainfall events including floods when the alkalinity and calcium water must be raised using lime. CO2 is critical for lowering the pH down to

In 2022 immediately after the biggest flood event yet recorded in the Tweed, CO2 supplier. The supplier, sighting force majeure under the contract, could treatment plant with CO2 due to the short supply and high demand of this chemical (particularly due to the food and beverage industry).

How did the problem impact you or your work situation?

It was unfortunate when Council’s supplier of CO2 delivered this news because very important to the overall water treatment process and our raw water quality required higher amounts of CO2 dosing. We needed to come up with a solution treatment processes to ensure we could continue to produce safe drinking water.

How long had the problem been occurring?

How long had the problem been occurring?

While we faced supply issues and force majeure in the past, we had never ran Typically we just had to bear the increased costs of force majuere. This was a

When the problem arose in March 2022, we were informed we could not receive end of the year.

While we faced supply issues and force majeure in the past, we had never ran out of CO2. Typically we just had to bear the increased costs of force majuere. This was a new problem. When the problem arose in March 2022, we were informed we could not receive CO2 until the end of the year.

Insert photo of the problem

Our solution was a temporary dosing line from the lime facility to dose lime as a slurry into the permeate channel. This acted as a solution for ensuring effective water stability and pH without CO2.

THE SOLUTION

How did you come up with the solution?

Council staff quickly sprang into action, devising a plan to dose lime as a pre and post chemical to target revised operational limits for alkalinity, calcium hardness and pH. Staff also jumped straight into trying to secure a supply of CO2 in the short and long terms.

Who helped work on the solution?

Brie Jowett, Anthony Burnham, Peter Haywood, Darren Lyndon, Matthew Tomson, Danny Flynn and Todd Remmers

Describe the solution.

Council’s water-supply operation is a 24/7 business and Water and Wastewater Unit staff are always on call. Darren liaised with Anthony, Brie and Peter over a weekend to establish new water quality targets and a revised water treatment process outside the typical design and function of the plant, which would ensure targets could be met. The revised process was clarified with industry experts, however the original concept devised by Council staff was ultimately a winner – the conversion of our existing lime dosing so we could pre and post dose lime to the revised operational limits.

Council’s technicians including Matt and Danny were also instrumental in ensuring the required code changes to the industrial computers at the plant were made to allow the revised process to occur.

In the background, Council’s Engineering staff worked with our contracts team to get a new supply tender out to market as quickly as possible. While the initial tender was not successful in securing a supply (as the entire supply market was struggling), working with industry bodies and market suppliers, we managed to organise 3 emergency deliveries. Staff optimised the plant to make the most of every drop of this emergency supply while we worked to secure a longer term supply. We were able to secure a long-term supply contract in December 2022.

While we now have a CO2 supply contract, we recognise the market for CO2 continues to be vulnerable to shortages. As such, we are currently working to ensure our pre and post dosing of lime can be made permanently available for any future supply shortages with optimal and safe operations.

How has it helped you at work?

Safe drinking water continued to be supplied to our community. We also learnt how to better optimise our CO2 supplies, which benefits the everyday operations of our plant.

Council is proud of the efforts of these staff to think outside the square and devise new methods of doing business while their backs were against the wall. Council staff often cop flack in our community relating to our initiative and drive. This example demonstrates how lucky

Council is to have staff that have such high levels of initiative and drive to overcome barriers and obstacles that threaten our core operations.

Considering the continuing logistical supply chain threats to chemical supply caused by pandemics, wars and natural disasters, Council is working towards addressing this risk to the safe drinking water supply and the ongoing management approach required to meet the needs of our water customers.

Following from our work with industry bodies, we are recognising the risks of the supply chain for our critical chemicals. We are now working on more robust Plan Bs that we can quickly and efficiently implement to avoid disruption or disaster due to chemical supply shortages in the future.

Suggest improvements, if time or financial limitations were not a factor.

The ultimate solution would be a dedicated lime-dosing facility that can provide flow-paced pump dosing pre and post the ultrafiltration membranes, and achieves alkalinity, pH and calcium hardness targets in the membrane feed water and the permeate and final treated water, without CO2.

Any other comments you would like to make?

Under the circumstances described above, the interim post lime-dosing approach was critical and supports what we already know – that our staff are critical thinkers and highly valuable to our community. We also hope the lesson might help others in the water industry.

UNDER PRESSURE: SOUTHERN RISING MAIN REPAIR

Sally Wood, Mackay Regional Council

THE PROBLEM

What was the problem that you experienced?

A leak on a critical sewer asset and main pipeline that carries sewage from various catchments throughout East, North, South and West Mackay to the point of discharge. This critical asset carries more than 18 million litres of sewage everyday throughout the city to the Mackay South Water Recycling Facility (MSWRF). A reactive response was to stop the leak with a repair clamp; however, it was apparent these temporary repairs did not address the core issue of poor construction methodology.

Particularly challenging was a lack of isolation valves on a 11km long DN914 mild steel cement lined rising main with only one isolation valve at the pump station and one at the recycled water facility. With temporary repairs failing, the threat of continual breakthrough of raw sewerage and potential overflow to the environment or customer complaints, the problem was how to safely and responsibly isolate the main to replace this section of pipe while being restricted to a maximum 14-hour overnight window before the system would fill up and spills would occur.

How did the problem impact you or your work situation?

The catchment of Mackay’s largest sewage pumping station, Sydney Street Sewerage Pumping Station, covers the Mackay City urban area, including 27,000 connected customers, from Slade Point to the North, Glenella to the West, and Paget to the South.

The objective of this shutdown and works was to allow for the required replacement of the damaged section of the Southern Rising Main (SRM) within the outlined time-period, without injury to any member of the team, without overflow to the environment and minimal disruption to the many connected customers and general public. Considerations included ensuring

favourable weather conditions (the first scheduled date was postponed due to a rain event that would have pushed sewage flows up) and the network to be drained within a suitable timeframe to allow repair and reconnection.

How long had the problem been occurring?

The leak first occurred in 2018, and repair clamps were utilised over a number of years as additional pinhole leaks surfaced, a sign of a much larger corrosion problem. Asset assessment identified the air valve offtake point four metres aways from the true high point meaning over a decade of corrosive gas cavitation that resulted in the inevitable breakthrough of raw sewage.

When a leak was called in from a member of the public while walking along the Mackay Cross City Link adjacent to Paradise Street it was clear that the latest temporary repair of early 2022 had also failed.

Insert photo of the problem

THE SOLUTION

How did you come up with the solution?

A dedicated project team was established to investigate all possible solutions including the following methods from consulted experts; installation of temporary inflatable line stops, construction of temporary storages and the installation of a temporary bypass. However, these were rejected due to being cost-prohibitive or the residual risks of a high-volume release of sewage to the environment during the repair.

Permanent repair options therefore centred on seeking endorsement for an in-line repair approach, identifying risks around cost, timing, and safety in implementation.

Hydraulic analysis suggested the optimum time to complete the works was overnight on a Friday or Saturday night as the industrial catchment would have very little internal flows which would allow maximum storage of transferred flows and observed flow data for the greater catchment indicating a general reduction in flows of an evening.

Who helped work on the solution?

The project was managed in-house with more than 55 crew members across over sixteen locations to handle the challenge of flow management and asset isolation to drain the main of 900kL to effect repairs.

Weekly team meetings held by the leadership team for the duration of the project.

A targeted and successful engagement strategy was developed by our corporate communications team to encourage low water use over the weekend of repair, which resulted in an almost 15% reduction on flows buying additional time to complete the works. The message went out via Facebook, radio, electronic billboards,

and the community connect project website. The use of humour and memes was used to engage and garner community support. Engagement with other key stakeholders and the regulator adopted a ‘no surprises approach’ to project delivery.

Describe the solution.

The proposal was to remove the damaged section of the pressure main and air valve offtake and replace it with a new custom-built section with a 900 mm mechanical gate valve with Gibault joints to connect into the existing cut section of the main. The 20-metre piece of pipework included two preinstalled air valves on either side of the gate valve.

The methodology developed for the project involved the isolation of more than 80 upstream pump stations and use of temporary overland piping and portable pumps to scour the affected section of rising main into a neighbouring industrial gravity sewer catchment (up to 288,000L per scour point).

The deployment of tanker trucks at identified high risk overflow locations allowed for cartage of flows to avoid an overflow occurring.

The Isolation and Draining plans documented the responsibilities of each team member: monitoring of the pump and of receiving manhole, assisting tankers at unloading locations, monitoring, and controlling the scour valve feeding the tankers and line valve isolation.

Despite the hours of preparation, the first night proved unsuccessful due to several factors:

• slower scouring/dewatering and closing of the inlet valve to the STP,

• issues with the intrinsically safe cutting machines procured

from Brisbane were not able to be installed and ready to operate in the time required,

• time taken for onsite earthworks.

Once the main was drained, testing devices were inserted to conduct an air sampling analysis within the pipe to establish if hazardous gases existed. As the read was within acceptable limits the uncovered pipe was sandbagged and building site was shut down and made safe and staff stood down at 1.30am in order to reassess work plans to resume the following afternoon.

improvements, if time or financial limitations were not a factor. of the Southern Rising Main was the most planned project ever undertaken by Mackay planning phases were reviewed during the project debrief session and areas for improvement noted as follows:

decision was made to cease this approach at around 11pm, our in-house team commenced cutting operations with our own quick-cut saws, with a large supply of cutting blades to swap out frequently and continuous watering of the cut area to stop the blades from getting too hot and shattering,

• the section of pipework was successfully cut and removed by crane at approximately 2.30am with new section then lowered and installed with works complete and the line brought successfully back into operation with no overflows by approximately 6.30am.

Stakeholder Engagement - Earlier engagement of Department of Environment and Science Scheduling/Timeline - the creation and use of a Gantt chart schedule would have valuable. Documentation - insufficient time allowed for full modification, suggestion for nominated completion of all documents, with any changes after this date requiring appropriate

How has it helped you at work?

The SRM Repair Project has bought many tangible and intangible benefits such as confidence and pride in a job well-done. It has served as a reminder to:

- due to complexity and time requirements, ‘Business as Usual’ tasks were neglected backfilling suggested during delivery phase to allow BAU tasks to be completed. Engagement of Contractors - full written scoping documents to be supplied to contractors for works.

Understand the risks and back the team:

Methodology - work should have been scheduled to be completed over two days, as the SRM on the second night was assisted by temporary air pressure introduced into after the first nights reenergisation,

The project team were challenged to identify opportunities to save time, develop an alternative cutting methodology and update the project plans to better reflect the time the project would take. Results from our flammable gas monitoring from the previous night were reviewed and demonstrated that although initially flammable gases do purge from the pipe just after the isolation, the gases dissipate very quickly and because with the pipe isolated no further gases are produced. A new risk assessment was conducted the incorporating reviews of Standard Operating Procedures (SOP’s) and the amended approach was communicated to teams in preparation to proceed that evening including:

• the alternative methodology developed that involved continuous gas detecting loggers to ensure explosive risk was not present,

Intent - identify the level of accuracy required for the project and time delay for installation to achieve this.

• staff were comfortable with the increased risk profile of quick cuts based on contingencies around cutting discs and watering to prevent overheating, the solution that was implemented was planned, designed, and delivered by internal staff with only a coatings contractor and cranage firm used to help complete the project.

solution - the intrinsically safe cutting machine was a great idea in theory but in application was not successful, we needed to build into our project plan time for them to come complete a test cut in the days prior to the repair for proof of concept.

comments you would like to make?

scouring occurred earlier in the afternoon and commenced prior to full closure of inlet valve for STP, this saved almost an hour on the scouring time of the previous night,

• the cutting team had configured equipment prior to the site closure on the first night and were ready to start, however issues with the intrinsically safe cutting machine meant the

Be agile and back yourself ‘to make the call’:

• if the No Go option needs to be decided, make the call early; a tough decision was made on the first night to stop the job and again on the second night to change cutting methodology, but we were confident to do with the contingency plan and in the team.

the truth of Ockham’s Razor – the adopted solution was the simplest to deliver in concept initially discounted due to a fear of isolating the network for an extended period and a that we couldn’t take this critical asset offline. These ideas were challenged, and the worked together to come up with a solution that was cost effective and able to be delivered predominantly in-house.

photo of the solution

Suggest improvements, if time or financial limitations were not a factor.

The repair of the Southern Rising Main was the most planned project ever undertaken by Mackay Water. All planning phases were reviewed during the project debrief session and areas for improvement noted as follows:

Stakeholder Engagement

• Earlier engagement of Department of Environment and Science

Scheduling/Timeline

the creation and use of a Gantt chart schedule would have valuable.

Project Documentation

insufficient time allowed for full modification, suggestion for nominated date for completion of all documents, with any changes after this date requiring appropriate approvals.

Resourcing

due to complexity and time requirements, ‘Business as Usual’ tasks were neglected backfilling suggested during delivery phase to allow BAU tasks to be completed.

Engagement of Contractors

• full written scoping documents to be supplied to contractors for specialised works.

Repair Methodology

work should have been scheduled to be completed over two days, as draining of the SRM on the second night was assisted by temporary air pressure introduced into the pipe after the first nights reenergisation,

Design Intent

• identify the level of accuracy required for the project and time delay for installation to achieve this.

Test the solution

• the intrinsically safe cutting machine was a great idea in theory but in application was not successful, we needed to build into our project plan time for them to come to site and complete a test cut in the days prior to the repair for proof of concept.

Any other comments you would like to make?

Trust in the truth of Ockham’s Razor – the adopted solution was the simplest to deliver in concept but was initially discounted due to a fear of isolating the network for an extended period and a perception that we couldn’t take this critical asset offline. These ideas were challenged, and the team worked together to come up with a solution that was cost effective and able to be delivered predominantly in-house.

Suggest improvements, if time or financial limitations were not It would be great to see industry specific training on the use of underwater supply, particularly if more water utilities adopt this technology.

USING AN UNDERWATER DRONE TO INSPECT WATER RESERVOIRS

Brie Jowett, Tweed Shire Council

THE

PROBLEM

What was the problem that you experienced?

Reservoir integrity is part of our Drinking Water Quality Management System. Like other water authorities, we are working to improve our reservoir integrity practices to best manage water quality risks.

In the past, our routine inspections occasionally identified potential issues that made it difficult to determine the quantum of the water quality risk and appropriate action. For example, we once found part of a snakeskin on the internal side of a reservoir access hatch, but we couldn’t determine if the snake was still there. At another time, we found an unusual number of small leaves inside a reservoir, but we couldn’t find a source.

Historically when events such as this happened, we hired a contract inspection company to investigate. Typically, they had long lead times. Sometimes, we have emptied reservoirs to inspect their integrity.

How did the problem impact you or your work situation?

Hiring inspection contractors and divers is costly and time consuming. Draining tanks is time and resource intensive, often resulting in other water quality or pressure complaints when tanks were bypassed and typical flow directions changed.

How long had the problem been occurring?

This has always been an issue, but with our increased focus on reservoir integrity improvements and the reticulation network risks to drinking water quality, we face these situations more often — we have been looking for them more frequently and have improved our inspection resourcing and processes.

Any other comments you would like to make?

Keeping the Tweed’s water reservoirs in tip top condition is part provide safe, sustainable and affordable water supply services as Tweed community.

Because prevention is better than cure, Council continues to spend we find in reservoirs. This has included upgrading hatch lids, replacing protection of vents and overflow pipes, and installing barriers on these points.

Council has implemented a procedural position to remove or trim reservoirs to ensure enough clearance to prevent snakes from accessing has been done in liaison with our environmental section and Council’s

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and the gap was

In this case, water quality results were completely normal but the inspection and actions taken are key to preventing future water quality incidents.

Insert photo of the solution

Brendan with the underwater drone.

Pictured is a snakeskin found in a reservoir during a routine inspection. Using the drone, we spotted the skin and a potential integrity issue (light penetration), which was not visible during an external tank inspection. We used the drone to confirm the snake was no longer in the reservoir

sealed.

Brendan with the underwater drone.

THE SOLUTION

How did you come up with the solution?

Our staff had heard about underwater drones and thought the technology might be a good first check when they find debris such as snakeskins or leaves in a reservoir. They knew they could also use a drone to look at reservoir ceilings for integrity issues and search the water for unwanted pests. For less than the cost of a single engagement of a contract dive inspection,

Council has bought a suitable underwater drone that is now used to verify possible risks to the water supply.

Who helped work on the solution?

Brendan Tyndall was tasked with researching the market and considering the option that would best suit our needs. He considered cost, the product quality for use in a water supply, lighting requirements, image clarity, extras such as robotics connected to the drone and ease of use. He trialled a drone before making the decision. Unlike aerial drones, there is no formal training for underwater drones, so Brendan had to work out how to operate the new device to maximise its usefulness. He first practised by booking out a lane in one of our Councilmanaged swimming pools. When confident, he used the drone in our water supply reservoirs. The company we purchased the drone from is now offering training, which we are considering.

Describe the solution.

Water and wastewater crews are now using drone technology to inspect the Tweed’s 40 water reservoirs, saving Council time and money. The underwater drone is fitted with a camera and a net to scoop up objects up to 2 kilograms.

How has it helped you at work?

Initially, we focused on using the drone to troubleshoot potential health problems in reservoirs.

Today, we use the drone for general inspections as well. By better understanding when works aren’t needed, our crews are reducing the amount of cleaning and maintenance work they undertake.

Since its introduction, we have had to check for snakes several times. This was because snakeskins were found inside hatches when we routinely inspected reservoirs. In these cases, snakes or other creatures were not found. This intel was developed quickly and became key to our investigation process and subsequent actions.

At one time, we investigated tank integrity after detecting unusually low chlorine residuals in an area of our reticulation network. The issue was pinpointed to one reservoir as the source.

When we checked that reservoir, it had zero chlorine residual. In response, we deployed the drone quickly and found a large dead snake on the reservoir floor. We also identified light coming in through gaps between the roof and the tank walls where caulking had been dislodged. We immediately concluded there was a breach in the tank’s integrity. With this evidence, we worked with NSW Health to issue a boil water alert. We drained and cleaned the tank, flushed all mains and fixed the tank integrity issues.

We have since agreed that drone technology is so highly effective it can take the place of our annual reservoir inspection program. Historically, Council employs qualified divers to examine the inside of each reservoir and to clean floors, under a risk-based program. We will now use Brendan and the drone to evaluate the reservoirs and measure sediment buildup. We will use professional contract divers to clean floors based on what the drone finds.

Suggest improvements, if time or financial limitations were not a factor.

It would be great to see industry specific training on the use of underwater drones for water supply, particularly if more water utilities adopt this technology.

Any other comments you would like to make?

Keeping the Tweed’s water reservoirs in tip top condition is part of Council’s commitment to provide safe, sustainable and affordable water supply services as the foundation of a healthy Tweed community.

Because prevention is better than cure, Council continues to spend money on sealing defects we find in reservoirs. This has included upgrading hatch lids, replacing flashing, ensuring grill protection of vents and overflow pipes, and installing barriers on stairs to limit snake access at these points.

Council has implemented a procedural position to remove or trim all trees surrounding reservoirs to ensure enough clearance to prevent snakes from accessing roofs from trees. This has been done in liaison with our environmental section and Council’s inhouse arborists.

STREAMING CURRENT ANALYSER

Brie Jowett, Tweed Shire Council

THE PROBLEM

What was the problem that you experienced?

Council uses a coagulant at its Bray Park Water Treatment Plant called Aluminium Chlorohydrate or ACH. This chemical has high levels of Aluminium. The chemical is dosed as a positively charged compound that interacts with micro-sized negatively charged sediment particles to bind together to form a “floc” (a larger sized sediment particle) that water treatment plant operators can remove by ultrafiltration. The dosing of ACH is a tricky business and presents a number of hazards associated with potential overdosing of the chemical. Also, the chemical is expensive. Establishing the correct dose for effective filtration without overdosing or fouling the ultrafiltration membranes is critical.

How did the problem impact you or your work situation?

Water treatment plant operators must change the ACH dose to reflect the prevailing amount of colour and turbidity in raw water. These are physical characteristics of the water that reflect the amount of small, negative particles bouncing around and require removal to produce safe drinking water. Overdosing ACH can foul ultrafiltration membranes, which can be an expensive issue

to resolve, and elevated amounts of Aluminum can enter the distribution system and threaten the health of Council’s water customers. Also, ACH costs about $1000 a tonne for Council to buy. As such, the correct dose rate is paramount. However, as a surface water catchment, Tweed’s raw water quality fluctuates and the dose needs to vary.

How long had the problem been occurring?

Council changed to ACH from Aluminium sulphate in 2015. Water treatment plant operators had been used to dosing high concentrations of Alum, which initially resulted in higher doses of

ACH after the change. While this had largely been resolved, high raw water turbidity events caused by rainfall in the catchment required operator adjustments to the ACH dose. A high Aluminium water quality event in the distribution network as well as close monitoring of newly replaced ultrafiltration membranes suggested the ACH dose was not being lowered quickly enough following high raw water turbidity events. The most recent overdosing event was in March 2021, which may have fouled the membranes

THE SOLUTION

How did you come up with the solution?

Our Operations Coordinator – Treatment and Catchment Darren Lyndon had previously operated a streaming current analyser and thought it might be a good potential improvement for the plant. He attended a WIOA Conference in Queensland where he gathered more information and spoke with suppliers. From this, he organised a trial of the analyser product to test his proposed solution.

Who helped work on the solution?

Darren Lyndon and Matt Tomson (Electronics Technician)

Describe the solution.

To address these risks, Darren Lyndon identified the potential to use a streaming current analyser. This device samples raw water close to the ACH dose-point and considers the relationship between the positively charged particles and the negatively charged particles. The instrument then communicates with the ACH dose pump to ensure the optimal ACH dose - a process known as trimming. Darren organised a trial of a streaming current analyser instrument as a means of ensuring it would answer Council’s needs.

This upgrade would not have been possible without the assistance of Council’s technician Matt Tomson, who was instrumental in installing, commissioning and operating the streaming current analyser, including a range of process-code changes and SCADA updates. Matt remains a key resource to the ongoing efficient operation of the streaming current analyser, including its analysis and calibration.

How has it helped you at work?

The trial was successful and saved Council 11 tonnes of ACH in 5 months. This represents a cost saving of about $11,000, associated with a more optimised dose of ACH and a much lower risk of overdosing.

Council has now purchased and installed its own streaming current analyser at a cost of about $15,000. The payback period was the trial period. The instrument will result in chemical cost savings and address drinking water quality risks into the future.

This small plant upgrade project packed a massive punch in addressing Council’s financial chemical costs. It also addressed risks to critical plant infrastructure and drinking water quality.

Suggest improvements, if time or financial limitations were not a factor.

An additional streaming current analyser (bringing the total number to 2) would provide additional and ultimate assurance regarding the performance of the ACH dose.

Any other comments you would like to make?

Council is proud to have these staff in its employ. They come to work ready to achieve the best outcomes within their areas of responsibility by identifying and implementing smarter ways of working.

Darren (L) and Matt (R) with the installed streaming current analyser.