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Optimising wastewater

treatment plant performance Wastewater treatment processes have been driven to reduce nutrient concentrations over the past couple of decades to improve receiving water quality, particularly in inland waterways. This has led to the installation of complex and often energy-intensive processes. Recently, focus has been on optimising existing treatment processes both in terms of energy usage and plant performance to maximise performance, capacity and operation of the plants.

A

urecon Associate - Water & Wastewater Treatment Susan Kitching will be presenting a paper on

Case study: Liverpool Water Recycling Plant One of the plants that was audited within the anaerobic digestion

optimising Sydney Water’s wastewater treatment

audits is Liverpool Water Recycling Plant (WRP). The plant treats

plant performance at Ozwater’15 on 12-14 May

wastewater from the South Western Suburbs of Sydney around

in Adelaide. The paper discusses a program of

Liverpool.

work that commenced in 2011 with Aurecon to

The plant consists of an inlet works, primary sedimentation

audit 11 anaerobic digestion facilities. Following successful results

and secondary treatment in a conventional activated sludge plant.

from this program, a second program was established to assess

Solids are collected from the primary and secondary treatment

the capacity and capability of their water and wastewater facili-

and treated in anaerobic digesters prior to dewatering and being

ties focusing on the performance of the system and operation and

taken off-site for beneficial re-use.

maintenance. The objectives of the program are to: • standardise operations where possible on good practice to optimise maintenance requirements; • consistently comply with effluent and biosolids land application guidelines/standards; • improve biosolids and effluent quality; and • improve operational efficiency.

The Liverpool WRP audit and BioWin modelling identified a number of short-, medium- and long-term modifications to improve digester performance. From these findings a number of modifications have been made to the plant to trial some of the recommendations, specifically that relating to recuperative thickening. The initial changes resulted in improvements to biosolids product quality, increased gas production and a reduction in operating costs. Following on from the initial success, between October and early 2014, the recuperative thickening has been optimised on-site to stabilise the thickening performance and hence the digester

Gas Produced (kg)

operation within the limits of the existing equipment. The increase in gas production can be seen in Figure 1 (approximately 30%).

Conclusion The auditing process as applied to Sydney Water treatment plants allows understanding of influent characteristics, overall plant mass balance and process unit performance. Examination of these, alongside operations and maintenance practices, and comparison to good practice can lead to optimisation of treatment facility assets and maximising available treatment capacity. Aurecon Pty Ltd

Figure 1: Gas produced as a result of recuperative thickening

www.SustainabilityMatters.net.au

www.aurecongroup.com

Apr/May 2015 - Sustainability Matters 33

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Sustainability Matters Apr/May 2015  

Sustainability Matters is a bi-monthly magazine showcasing the latest products, technology and sustainable solutions for industry, governmen...

Sustainability Matters Apr/May 2015  

Sustainability Matters is a bi-monthly magazine showcasing the latest products, technology and sustainable solutions for industry, governmen...