On the 12th of May, 2015, a sequence events began that, 10 days later, would culminate in a major hydraulic incident leaving the Yering Gorge pumping station critically damaged and exposing the operator on site to significant risk. This event would result in the station being out of operation for two months before partial pumping could be reinstated and a total of eight months before the station would again operate at its full capacity. The ultimate cost of this incident included approximately 10 Gigalitres of lost water harvest and a significant restoration operation costing over $1.2 million. This paper describes the events leading up to the incident, the investigation process and the key learnings identified.

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North East Water (NEW) took over control of the Wangaratta Trade Waste Treatment Plant (TWTP) during May 2015. The TWTP services two textile customers only. Textile waste is very different to sewerage, as it largely consists of poorly biodegradable ‘chemical’ waste, which has elevated concentrations of colour, metals, nutrients and salts. The treatment processes consist of a number of biological and chemical treatment processes and discharges to a local creek under EPA licence. When NEW took over the operation of the plant, it became quite apparent that a number of challenges and knowledge gaps were present, namely meeting licence requirements, limited process control and automation, accumulated sludge as well as broader reputational and ecological considerations. A game plan followed by significant changes needed to occur.

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As a result of the extended dry conditions experienced during 2014 and 2015, many farmers in the Wimmera who rely on surface water dams ran out of water. In December 2015, the Victorian Government provided funding for a number of drought relief projects, including Electronic Swipe Card Stand Pipes (ESCSP) in GWMWater’s region.

Funding of $420,000 was provided to supply and install 14 ESCSPs in strategic locations across the region to provide farmers with 24/7 access to water via water carting. A trial ESCSP had been installed 6 months previously in the Landsborough area, with the success of this trial enabling the efficient roll-out of the additional ESCSPs at a known cost.

The new ESCSPs generally replaced existing ‘manual’ Stand Pipes. Many of the old stand pipes had OH&S issues such as ‘top fill’ connections. They also relied on the water carter to record the date and consumption at the nearby corner store or honesty box. This system was problematic with records and subsequent billing poorly accounted for.

The new ESCSPs allow 24 hour access to water carting in the drought affected rural areas for landowners that are not connected to the water supply network.

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Chlorine gas is an agent used for primary disinfection of drinking water and disinfection of treated effluent. Melbourne Water has 920kg chlorine gas drums installed at five sites, and 70kg chlorine cylinders at two sites, which connect to a common manifold via an auxiliary valve, pigtail and manifold valve. In February 2016 discolouration was found on the nuts of pigtails at two sites which indicated possible corrosion and the potential for a chlorine leak. An organisation-wide incident was declared and all pigtail/valve connections were systematically inspected for evidence of corrosion. Symptoms of corrosion included discolouration or removal of plating, deposits of corrosion products, moisture leaking out of connections, and valve threads that were brittle or missing in parts.

The last symptom was of critical concern as loss of thread integrity could lead to a loss of containment of chlorine gas. A detailed incident analysis was completed and examined many potential root causes including moisture ingress, leaking gaskets and dezincification of the brass. Actions from the incident included modifications to standard operating procedures, maintenance regimes, procurement procedures, equipment specifications, and asset information recording. While the exact root causes were not established, the understanding gained through the investigation process allowed the incident team to develop control measures to resolve the issue.

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There are currently six Chemical Dosing Facilities in operation across Yarra Valley Water’s sewerage network. These facilities all use the chemical Magnesium Hydroxide Liquid (MHL), and dose the chemical with the objective of reducing odour and minimising the extent of corrosion at points throughout the sewerage network.

In 2014/15, Yarra Valley Water spent nearly $180,000 in purchasing the chemical. Due to the significant chemical cost, Yarra Valley Water’s Sewer Optimisation Team was tasked with investigating more efficient dosing philosophies for its dosing facilities.

This paper describes the findings from Yarra Valley Water’s investigations into the dosing philosophies, including:

• How a saving of $80,000 was achieved during 2015/16, despite the addition of two new dosing sites to the network. This included a saving of $20,000 per year in chemicals from one facility alone.
• What monitoring equipment was required to be installed downstream of the dosing facilities to implement the new dosing philosophy.
• What modifications were required to the existing dosing facilities.
• How the more efficient dosing philosophy was developed and refined.

The new chemical dosing philosophy was found to be a success. It is currently being replicated across the remainder of the chemical dosing facilities in Yarra Valley Water’s sewerage network.

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This paper discusses the risks that existing cross connections pose to Water Corporations and the provision of quality water to its communities. An event that occurred at Gippsland Water in 2015 led to the Corporation addressing the factors that contribute to cross connections. Based on this analysis a number of practices to support the identification of cross connections were identified with Gippsland Water finding that cross connections were not limited to the normal operational flows at a water treatment plant.

Furthermore the Corporations examination of cross connection prevention methods identify the circumstances that support removal as opposed to isolation of cross connections and the use of Backflow / Non Return Valves (NRV) as an effective prevention mechanism. In conclusion this paper essentially highlights the importance for Water Corporations to adopt a multifaceted approach to a cross connection identification and isolation process that minimises unnecessary risks to its operations.

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Similar to many small and medium sized sewage treatment plants, Cowra Council has an issue with the de-watering of sludge. Over the last few years, Council has looked at many different ways of de-watering our sludge; investigating various technologies from a range of operators and companies who all profess to have the perfect solution to our problem.

After many hours of sorting through cost, efficiency and usability, we decided to look outside the box.

We learnt of a small company in Texas, USA who developed their own system. One of their boxes was imported to Australia and hired on a trial basis by Cowra Council; the first of its kind to be used in Australia. The simplicity and efficiency of the system is the key – no high electricity costs, no belts, pulleys, bearings or bits, just a mixer, delivery pump, poly unit, the box and a truck.

The system could be used across many industries in different applications. Facts and figures from the trial de-watering of one five megalitre sludge lagoon are presented in this paper and by the time of the conference more data will be available.

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The Palmerston North City Council Wastewater Treatment Plant was having problems with non-compliant Industrial wastes being received at the plant. Something needed to be done to combat this problem.

An S::CAN unit was purchased and using iceberg analysis the process of identifying the constituents in the wastewater began.

This technology has proven to be successful in identifying industries having difficulties complying with their consent conditions. It has helped staff understand the influent being received as well as identify illegal discharges received at the plant.

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In early February 2016, Goulburn Valley Water received Blue-Green Algae data from Goulburn-Murray Water (G-MW) and the Murray & Sunraysia Regional Algal Coordinating Committees (MRACC) advising of elevated Blue-Green Algae bio-volumes upstream of GVW’s Murray River offtakes. Analysis of this data triggered an additional urgent sample run on the 19th of February for Barmah and Cobram. Based on the results from these two samples the MRACC immediately issued a BGA Red Alert for these localities. This paper documents the operational challenges during the three month event and the steps taken by Goulburn Valley Water prior to and after the issuing of the Red Alert, including the preventative actions at Barmah and Cobram prior to the alert, the installation and commissioning of a trailer mounted bulk bag PAC dosing unit at Numurkah and temporary dosing systems setup at Picola and Nathalia.

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Biogas production from wastewater streams is one of the answers to the energy and environmental needs of the future. Many water authorities are either operating Anaerobic cogeneration plants or have the potential to convert their anaerobic plant to a cogeneration facility. Treating wastewater streams though an anaerobic process to produce biogas energy and treated wastewater simultaneously can provide a significant economic boost for water authorities. Two of the key parameters in maximising the economics of biogas generation from Anaerobic systems are the management of H2S formation in the gas and the consistency of the gas generations. Addition of an alkali is typically a critical part of the Anaerobic system for maintenance of pH and alkalinity. Many water authorities do not take advantage of the energy potential their anaerobic systems offer via biogas capture and conversion. Australia only produced 1% of its electricity in 2014 from bioenergy (Clean Energy Australia Report).

A case study was done on a piggery in Victory that had been producing electricity since 1991 and it was looking to improve biogas/electricity production from the piggery wastewater stream though it anaerobic reactor. This case study started with doing simple lab testing to determine the correct dosing rate for the field trial. In a static the lab trial hydrated lime, caustic soda, standard magnesium hydroxide and ACTI-Mag were tested as potential Alkalis. The ACTI-Mag showed a 3 fold increase in biogas volume generated compared to the other alkaline materials. From this lab testing it was found that between 100-200kg/ML was the optimum dosing rate for this operation. In the field trial 125kg was used on the raw wastewater with the following improvements. 1. Biogas volume increased by 20% 2. Power generation increased by 23.5%. 3. The soluble phosphate reduced by 37.5% in the final waste stream. 4. The H2S level reduced from 800-600 ppm range to below the 200 ppm level. 5. Struvite formation in the pipes and the bell was not seen during the trial having previously formed on regular bases.

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Veolia is collaborating on research into water and waste treatment technologies, under a five-year Memorandum of Understanding with the University of Melbourne (MoU, 2015-2020). The first project focused on sites at Australia’s Casey Station, operated by the Australian Antarctic Division (AAD), in East Antarctica. This project aims to utilise low-energy biological processes, such as biofiltration, to treat summer melt water contaminated with diesel-based hydrocarbons.

Veolia’s technical experts and operational staff have had the opportunity to participate in a water treatment plant development project at Casey Station, Antarctica. Under the direction of University of Melbourne Project Team Leader, Kathryn Mumford, and Australian Antarctic Division (AAD) Project Manager, Tim Spedding, the team were commissioning and operating a plant to treat water as part of the clean-up of contaminated sites impacted by diesel spills in Antarctica.

This paper will describe the process of retrofitting and re-commissioning a package water treatment plant designed to operate in the extreme Antarctic environment.

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Victorian Water Corporations are quite adept and resilient in responding to minor incidents. However in October 2015, North East Water (NEW) had a significant sewer spill incident on the flood plains of the Ovens River which escalated both at a municipal and state level. Managing the response, recovery and expectations of external agencies highlighted new challenges for North East Water.

This paper outlines NEW’s response to the broken rising main incident, with a focus on external stakeholder interaction and the long road to recovery.

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Queensland Urban Utilities (QUU) operates 28 sewage treatment plants which combine to produce approximately 150,000 wet tonnes of biosolids per year. To manage this product QUU developed the Biosolids Strategy in 2012. One of the key goals of the strategy is to identify and implement operational cost saving initiatives. Sandgate Sewage Treatment Plant (STP) is one of the 28 plants under QUU’s operation and it produces approximately 8,000 wet tonnes of biosolids per year. This paper will be looking at biosolids management at Sandgate STP and its role in meeting the Biosolids Strategy.

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There are several chemicals that are commercially-available for the disinfection of drinking water; however, disinfection with different forms of chlorine (chlorination) is still the most used form of disinfection throughout the world. Although chlorine has good disinfection properties, it can make the water unpalatable and has the potential to cause adverse health effects if it is present at high concentrations. Therefore, based on health considerations, the 2011 Australian Drinking Water Guidelines (ADWG) provides health-based guideline value of 5 mg/L, as total chlorine, in drinking water.

Additionally, chlorine can react with organic substances present in the water and form potentially harmful disinfection by-products (DBPs). Hence, it is important to manage the chlorine dosage, such that it is sufficient to achieve targeted pathogen inactivation, whilst minimising the formation of DBPs or creating other undesirable aesthetic issues. During 2015 Coliban Water had five instances where treated drinking water that contained chlorine at a concentration greater than the ADWG guideline value was either supplied, or could have been supplied, to the customers. The objective of this paper is to share the learnings from these events in order to prevent, or minimise the chance of, similar events occurring elsewhere.

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Yarra Valley Water has seen a rapid expansion in its capital delivery program due to population growth and land development, rising from $88M in 2003/04 to an average of over $200M per annum for the last 5 years.

Operational perspective in the design and construction is critical to produce higher quality new assets which function effectively and meet our customers’ needs. Operational involvement is also required to successfully commission and integrate new assets into the live network. To maintain this high value operational input across a much larger capital program, Yarra Valley Water has formed an “Asset Integration Team” made up of dedicated operations resources who work directly with the Project Managers responsible for capital works.

The Asset Integration Team is responsible for:

• Design reviews with a focus on ensuring new assets will be safe and easy to operate and maintain.
• Support during construction, commissioning and acceptance testing
• Acceptance of the commissioned assets, and integration into existing networks
• Acceptance of required documentation e.g. manuals, drawings, procedures, etc.

The team was first introduced in 2007-08 to assist with the Pressure Management Program and was subsequently expanded to include all new major water and sewer assets. In 2015 the team was expanded again to include Treatment Plant projects. Over this time, median commissioning times have reduced from 8 months to 4 months.

This paper will outline the benefits that the Asset Integration Team provides to Yarra Valley Water, including a case study on the new Wallan Sewerage Treatment Plant.

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Industry practices have varied in the control of microbial growth and biofouling of membrane filtration systems in recycled water applications. Some of the strategies utilised include chlorination/dechlorination, chloramination, Sodium Bisulphite and Biocide dosing in Feedwater. Each strategy has its advantages and disadvantages; as well as associated operational risks including risk of oxidation of RO membranes. It is well documented that any free chlorine can damage polyamide RO membranes which is further oxidised in presence of transition metals. RO performance deterioration is typically characterised by reduction in salt rejection and permeate flow.

Altona Salt Reduction Plant (ASRP) is an UF and RO (two pass) recycled water plant, owned and operated by City West Water (CWW). It receives tertiary treated effluent from its wastewater treatment plant. This paper summarises ASRP’s experiences with a non-oxidising and biodegradable biocide, DBNPA and provides insights into alternative methods to manage biofouling in membrane filtration systems. The paper will also compare operating cost of using Chlorine/dechlorination Chloramination and DBNPA dosing.

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The Mount Pleasant Water Treatment Plant (MPWTP) in the Adelaide Hills has experienced sub-optimal performance since it was commissioned in 2000. The conventional train has not been able to achieve its design capacity of 15 L/s, with a sustainable limit of 10 L/s. Higher flows result in excessive floc carryover into the granular media filters, with consequent rapid head loss and low filter productivity. In March 2015, the UF membrane treatment train began to show evidence of irreversible fouling, with decreased permeability in filtration and backwash modes. It was proposed that the combination of in-line alum dosing onto the UF membranes and sludge thickener supernatant recycle were the main contributing practices. Module autopsy confirmed presence of aluminosilicates.

Extensive chemical cleaning was unsuccessful in restoring performance, confirmed by laboratory cleaning studies. Strategic investigation was initiated to develop management plan for new membrane procurement to prevent re-occurrence. The significant operational issues with both Streams catalysed a process design and operations review, including alternative coagulants. Two aluminium chlorohydrate (ACH) products and a polyaluminium chloride (PACl) were selected. Testing was undertaken with and without MIEX® pre-treatment. UF performance stabilised once ACH/PACl dosing commenced. Optimisation of conventional train performance was more challenging with respect to achieving improved floc formation, clarification and filtration. This paper will describe the operational challenges and successes associated with a ‘beyond alum’ approach to water treatment.

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Wannon Water has been undertaking a research and development project to determine the impact of fish on the accumulation of sludge in lagoon based sewage treatment plants. Trials have been underway for 7 years in partnership with Deakin University. Tank trials using primary effluent show fish can reduce the total volume of sludge up to 46% over 70 days. Full scale trials are now underway at Hamilton and Port Campbell Water Reclamation Plants (WRP’s) to quantify the impact of fish in primary lagoon systems. This paper gives an outline of the research undertaken, what we currently know, and the potential for this innovative technology in the Water Industry.

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From April 2014 to October 2015, the residents of Flint, Michigan, USA were supplied with water from the municipal drinking water supply that was arguably unfit for human consumption. Due to changes in source water, the community was exposed to lead concentrations in their drinking water that far exceeded USEPA standards. For 18 months community concerns about their water supply were not acted on and an independent inquiry found that many individuals and groups, including local, county and state officials contributed to the disaster.

The events leading up to the Flint crisis were complex and difficult. The handling of the situation has been examined in minute detail and many players have been criticised. The question for the Australian drinking water industry is whether this event could have happened here and if our current approach to water risk management and our response to customer concerns are robust enough to make sure it never does.

Information for this paper has been drawn from the following documents and web sites: Flint Water Advisory Task Force – Final Report (March 2016); The Toxic Tap – Time Magazine February 1, 2016; Flintwaterinfo.com; Flintwaterstudy.org and numerous news reporting and commentary web sites.

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The 2016 blue-green algae (BGA – cyanobacteria) bloom affecting the Murray River demonstrated the need for a coordinated, whole of government approach when dealing with a bloom affecting multiple states and regions in Victoria. The response arrangements and communication of key messages was complicated by the unpredictable nature of the BGA bloom and uncertainty around the potential impacts of BGA toxins to public health. The detection of a species of BGA not previously found in Victoria, Chrysosporum ovalisporum, highlighted the ever evolving complexity of bloom dynamics. This species has the ability to produce toxins, however the factors influencing toxin production are not well understood and toxin production therefore cannot be easily detected, quantified or predicted.

The Department of Health and Human Services is reliant on the best available science to inform decisions and the provision of timely, evidence based advice when dealing with potential risks to public health. Due to the complex and unpredictable behaviour of blooms, water suppliers and water storage managers require agility in their response and robust and resilient water supply systems. As we continue to encounter variable climatic conditions and issues relating to water scarcity, BGA blooms are likely to be an ongoing risk to water quality into the future.

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Victoria’s Safe Drinking Water Regulations 2015 (the Regulations 2015) were introduced in July 2015, placing a greater emphasis on managing risk relating to drinking water quality. An important improvement was introduced relating to the requirements around detections of Escherichia coli (E. coli) as a microbial indicator of water quality. Following detection of E. coli in drinking water, the new regulations provide for water suppliers to claim a false positive sample if, after conducting an investigation according to particular criteria, it is confirmed that the presence of E. coli is not representative of the water supplied in the water sampling locality. This change has not resulted in an appreciable change in the numbers of E. coli detections but has provided a framework for the systematic investigation of detections which have resulted in improvements to system operations. This has highlighted the importance of considering tanks in greater detail as both sources of E. coli detections and points of failure of infrastructure integrity.

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