Victoria’s Safe Drinking Water Act 2003 (the Act) came into effect 1 July 2004. The Act sets out the responsibilities and legal requirements for the Victorian water industry in relation to the provision of safe drinking water. Since the commencement of the Act, there have been many notifications to the Department of Health of known or suspected contamination of drinking water relating to system failures. Whilst many of these have been minor in nature, there have been notifications where customers have potentially been supplied with unsafe drinking water. Issues beyond the control of the water business have caused many of these system failures, but, there have been several cases where underlying causes of the system failure were foreseeable and preventable. This paper highlights three case studies where the system failures could have been prevented.

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In 2009, Goulburn Valley Water (GVW) introduced a Sewer Network Odour Management Strategy. As a result of the strategy, priority odour and complaint sites where identified for measurement logging of hydrogen sulphide gas (H2S). These sites are monitored over the summer period where their risk priority is monitored on an annual basis. Sites with the high risk of odour problems are investigated in order to reduce the potential of emitting odours. The potential of odour emissions is reduced by odour control units, sewer vent stacks, ventilation fans, sewer rising main alterations, manhole alterations and the improvement of existing odour control.

The Merrijig sewage pump station was a high potential odour risk and was rated high on GVW’s Annual Sewer Odour Network Management Program report in 2010/2011. This pump station was replaced in 2002 with in situ concrete and epoxy lining. Due to the high odour risk rating, the poor structural condition of the wet well, the rapid deterioration and imminent failure, the wet well not only required replacement but the new material type required investigation.

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Yarra Valley Water’s DN900 M340 Craigieburn Reservoir Outlet distribution main is one of the company’s most critical water supply assets, forming the primary supply to the Hume Corridor and servicing parts of the northern suburbs of Melbourne. In excess of 10,000 customers would be directly impacted by any disruption to this main. This paper outlines the steps taken and the experience gained in executing a planned outage of this main.

Significant development along the Hume Corridor, and the construction of a new arterial road brought about the need to relocate a critical fitting, requiring the main to be shut down. This provided a fantastic development opportunity for an inexperienced operator.

This system has several, flexible modes of operation not previously used. Most significantly for this outage was the Craigieburn pump station reservoir by-pass mode, which provides the only alternate supply to this area, should the reservoir outlet main be unavailable. This operating mode is highly dependent on the reliability and redundancy of the distribution network, which forms the ‘backbone’ for the alternate operating mode.

This alternate operation required extensive field checking and trialling to ensure our customer service levels could be maintained during this extended period. Coordination of resources from Yarra Valley Water (YVW), Lend Lease (YVW’s Maintenance Contractor) and sub-contractors was required during both the trial and actual shutdowns.

Following weeks of planning and trialling the shutdown went ahead in February 2012. Through the rigorous use of YVW’s OCCP process, a shutdown with the potential to disrupt supply to thousands of customers was executed seamlessly, resulting in no customer complaints or system issues within the Hume Corridor.

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Heavy rainfall and subsequent flooding in the Goulburn Valley Region has prompted Goulburn Valley Water (GVW) to take measures to protect numerous assets and improve services during such events.

The Central Operations and Maintenance (O&M) team at GVW has optimised the way in which the sewer pump stations in Shepparton operate during a heavy rainfall event. Three catchments that experience regular sewer spills during heavy rainfall were identified, and a control program put into place to manage sewer pump station run times. This has resulted in the elimination of sewer spills from these sites.

Flooding in the town of Numurkah threatened a number of GVW assets, in particular the sewer system. The Northern Operations team responded quickly and proactively to protect assets and minimise the impact of the floods on customers, resulting in no customer complaints relating to the sewer system for the duration of the flood.

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Historically, Yarra Valley Water (YVW) has experienced seasonal blue-green algal blooms which restrict the ability to supply recycled water to customers and often require the use of costly algaecides to control. During 2011/12, YVW conducted an investigation into several alternate control methods promoted as preventing the formation of BGA blooms. The intent of the study was to develop an understanding of their; mechanisms of action, ease of implementation and effectiveness. The control methods investigated included application of barley straw, surface aeration, ultrasonics and lagoon recirculation systems. An additional study was commissioned to ensure that the application of barley straw would not compromise the use of recycled water for Class A production from a water quality perspective.

The control methods were trialled in four separate recycled water lagoons with another lagoon used as the control. Water level and blue-green algal counts were recorded weekly during the peak reuse summer season in 2011/12. Results suggested algae levels were somewhat controlled throughout the trial period in most lagoons when compared to the control water body, with algae growth occurring only when environmental factors sharply altered. Various external factors during the course of the trial decreased the confidence in determining the effectiveness of the algae treatment methods.

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The Shepparton Water Treatment Plant (WTP) can treat up to 114 ML/day. The site consists of four separate treatment plants that have developed with demand augmentation requirements; two of the plants are hopper bottom clarifiers, one mechanical clarifier, direct filtration common plants and a DAF(F) (Dissolved Air Flotation (Filtration) plant.

DAF(F) is a well-established and a popular water treatment process. One of the emerging challenges for DAF(F) treatment plant operators is optimising the DAF process to improve the quality of subnatant water entering the filter and the performance of the DAF(F) when experiencing relatively high turbidity raw water (>60 NTU).

Operators have undertaken a number of process improvements relating to the location and operational control of a streaming current meter; the dosing of coagulants; extensive trial work associated with recycle rates, supernatant return, dispersion control valve configurations and filter control.

There has been a wide variability in the performance of the DAF system. This paper seeks to explain key aspects of work undertaken at the Shepparton WTP to improve the DAF process, in particular improvements relating to producing high quality subnatant water. The paper also details what can be expected from DAF performance and some known problems with DAF systems. The aim here is also to provide some background on levers that may be available to operators of DAF plants to optimise the performance of existing assets using our experience at Shepparton WTP as a guide.

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Organisations with settlement and treatment lagoons or raw water storages need to periodically carry out de-sludging or de-silting processes, in order to maintain overall storage capacity or minimum water levels above sludge layers. Some sediment or sludge removal methods are highly sensitive to sludge density, reliant on rudimentary measurement techniques or multiple laboratory test samples to estimate when critical sludge or sediment densities and depths have been reached.

Confirming sludge depths, densities and quantities can have many benefits, such as optimised operations, and better forward planning and budgeting. Cost savings can also be achieved through deferring de-sludging or de-silting until needed. This can be achieved by use of modern hydrographic surveys which incorporate traditional survey methods, GPS technology, a hydrographic echosounder and a Portable Suspended Solids Monitor to determine the percentage of solids, sludge blanket interfaces and depths.

These surveys are non-invasive and can normally be done concurrently with lagoon treatment operations, and over time be used to build up deposition history and predictive trends.

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During the late 1990’s, as part of multiple town water treatment upgrades, North East Water (NEW) engaged many communities with the aim of achieving their most suitable water supply improvement. The Myrtleford community was quite active and very passionate about their water supply, assuming that it was ‘pristine’ in quality, and therefore strongly opposed any chemical addition, particularly Chlorine. At the time, an innovative solution was introduced, however this eventually led to a supply that had a single UV disinfection barrier only. In a nutshell, although the community were satisfied with the water quality, this solution did not provide safe drinking water. Multiple E. Coli detections in the reticulation resulted in a seasonal boil water notice and undertaking with Department of Health to fix the issue.

Potentially, NEW could have simply added chlorine to the water supply, however continued to consult and work with the community to ensure the best solution for both parties could be achieved. With ongoing strong opposition to chlorine, NEW made commitment to construct a multiple barrier WTP with emphasis on ensuring a low and consistent dose of chlorine.

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On behalf of the Western Australian Department of Housing, Parsons Brinkerhoff manages essential services to 91 remote Aboriginal communities through the Remote Area Essential Services Program (RAESP). The water treatment team at Parsons Brinckerhoff, Perth, designs systems to produce water from the community bores that meets Australian Drinking Water Guideline (ADWG) standards.

At some places in Western Australia, arsenic levels in community water supplies exceed the level set in the ADWG. This paper discusses the options available for removing arsenic, and their suitability for extremely remote communities.

The final design was based on installing adsorption media in a 3.0 m shipping container, to maintain a minimal footprint and protect the plant from the environment.

When exhausted, the adsorption media is removed from the vessel and either stored on site to minimise disposal costs or disposed of safely, once a year, into land fill.

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I love a sunburnt country
A land of sweeping plains
Of rugged mountain ranges
Of droughts and flooding rains

And that is how 2010 ended and 2011 started – with the flooding rain bit.

It was water water everywhere and not a drop to drink.

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The Solids Retention Time (SRT) is an important operating parameter of an activated sludge wastewater treatment plant, as it gives an indication of the plant’s biological state. An overly long SRT is associated with extra aeration demand, and can limit settling capacity in clarifiers and Sequential Batch Reactors (SBRs). There is also a relationship between SRT, temperature, and the ability of the plant to nitrify. The Mixed Liquor Suspended Solids (MLSS) concentration is frequently used instead of SRT as the basis for plant operation as it is simple to measure and is generally part of regular plant monitoring. Often MLSS gives a reasonable approximation of SRT, however this convergence can drift over time with changing influent loads and chemical dosing. SRT cannot be measured directly as it is a function of the influent loads, chemical dosing, sludge wasting rates, and solids capture efficiencies.

A spreadsheet-based SRT calculator was developed for the Colac Water Reclamation Plant (WRP) to account for all these factors. The aim was to produce a simple tool that was easy to use and provided operators with information on the current sludge age, the wasting set points required to reach a targeted sludge age, and also provided a direct correlation between the MLSS observed within the reactors and the SRT. This paper discusses the theory behind the development of the SRT calculator, how it was customised to the Colac WRP, and the experiences of the operator using it in actual operation.

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Bendigo and Castlemaine water treatment plants (WTPs) are designed, constructed and operated by Veolia Water Australia (Veolia) under a 25 year “BOOT” contract. Veolia operates these WTPs’ on behalf of Coliban Water, under strict water quality licensing conditions. After almost 13 years of drought, Central Victoria experienced a period of extremely high rainfall from mid 2010. Storages filled from record low levels to 100% full in a matter of months. The raw water quality changes resulting from these high rainfall events were dramatic, with increased colour, turbidity, dissolved organic carbon (DOC) and elevated iron and manganese concentrations.

At around the same time as these extreme rain events occurred, the Veolia Bendigo operations team was involved with the change-out and upgrade of the entire membrane inventory across the three sites. The raw water quality changes, coupled with a new type of membrane and new chemical cleaning systems, posed challenges for the team to understand the most effective means of managing the raw water quality and maintaining membrane performance.

This paper will describe the impact of the changed raw water quality on the newly installed membranes, and compare and contrast the performance of PP membranes and PVdF membranes under these water quality conditions.

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In 1994 a new sewage pump station used a redundant 24 year old asbestos cement water main as its rising main. In the reverse direction, this main now had a crest along its length after which it acted as a drain. In 2011 the pumping system was altered, subjecting this pipeline to minor pressure increases and within a few hours, the rising main suffered two bursts just downstream of the pipeline’s crest. This pipeline had no recorded bursts over its life.

Samples of the repaired sections were inspected and corrosion of the top of the pipe from the inside, was evident. The cause was attributed to sulphide attack in the gas head space above the sewage in the section of main where only part full flow was ocurring. The difference in pipe condition between the invert and obvert was due to the regular rinsing of accumulating acids from the invert only. Other samples of the rising main prior to the crest, revealed an AC pipe in perfect condition.

Westernport Water has another similar rising main that is planned for inspection in 2012. It is believed that other water corporations may also have asbestos cement or cement lined rising mains that are subject to this mechanism of corrosion.

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Mobile Information Management System (MIMS) is an information system used to collect and manage reactive and planned maintenance in the field. As the name suggests, it allows for information to be used in a mobile manner in the field by operators. MIMS has introduced a new program “Focus” which integrates with Wannon Water’s current customer relations system, Aquatact, as well as GIS and Conquest.

This paper outlines the process in which MIMS has been implemented to field operators in Systems Operations at Wannon Water. It also explores the objectives and benefits in transitioning from a paper based process to delivering all respective maintenance findings and reporting online.

MIMS was rolled out on 20 February 2012 at Wannon Water in the Systems Operations Team and looks to expand to further teams within Wannon Water. Systems Operations is split up in to 3 teams being Central, East and West. Within these teams there are currently 29 tough book laptops in the field as well as 34 field operators using MIMS.

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I would like to introduce the proposed framework for the national certification of water operators. I became involved in the project called “The Certification Framework for Operators of Drinking Water Treatment Systems” when I commenced with GSA in November 2011. The certification framework provides an assurance to regulators, communities and consumers that certified operators who treat drinking water are competent to perform the tasks required to ensure it is safe and are capable in identifying and responding to water quality risks and incidents.

It was explained to me like this – you need to have a 4 year trained licensed electrician to come into your workplace or home to fix a power point but there is no requirement for someone who operates a water plant that could impact a whole communities drinking water and their health.

This framework introduces a minimum competency standard for operators across all states and territories by aligning skills, knowledge and competency requirements to VET standards. It also ensures there is a requirement for on-going maintenance and development of skills and knowledge.

This project has been funded by the National Water Commission and was carried out by Government Skills Australia. The project commenced in June 2011 and the final report was delivered to the Water Commission on April 2012. At this stage the framework is only a proposal what is adopted and when is yet to be decided.

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Ensuring that skills and training of staff are concurrent with ever changing legislations, codes and striving for continued improvements for industry best practice will always provide a challenge in any industry.

For North East Water, as with many other organisations, the challenge was compounded by having valued long term employees with experience gained over many years, in some cases over thirty years in the water industry. The issue was to find methods of continually providing information, instruction and training that did not make staff feel they were being made to “suck eggs” and that was seen as a value added addition to their careers.

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Dungog WTP is located in the lower Hunter Valley in NSW and was commissioned in 1989. It is a direct filtration plant with 10 dual media filters and a maximum capacity of 90 ML/d. Dungog WTP supplies parts of Newcastle, Dungog, Maitland and the Lower Hunter region of NSW. The plant is supplied from the 20,300 ML capacity Chichester Dam. Chichester Dam is encompassed by a large and fruitful catchment area that results in high turnover of dam water during heavy rainfall events and rapid change of raw water quality entering the Dungog WTP.

Raw water turbidity can vary between 1 NTU to as high as 120 NTU. As Dungog WTP is a direct filtration process, these rapid turbidity changes put a lot of strain on the filters and therefore create a need for adaptable coagulation and flocculation dosing systems. The direct filtration process commissioned for Dungog WTP incorporated automatic adjustment of coagulant and coagulant aid polymer dosing based on raw water turbidity. There is also the capability to dose hydrated lime to adjust coagulation pH during periods of elevated turbidity. Over the ensuing years and after multiple challenging high turbidity events, a range of strategies have been employed to optimise and fine-tune monitoring and control of chemical dosing systems with the aims of better managing raw water quality risk, improving treated water quality performance, minimising capital and operating costs and ensuring the safety of treated water to a high volume of public consumers.

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