Like many other Victorian water businesses, East Gippsland Water (EGW) has a strong focus on reducing operational costs and over the years and has implemented a number of programs to reduce electricity consumption, after-hours operator response and chemical usage. One idea that was floated (pun intended) was that in times of good raw water quality we would run our Dissolved Air Floatation (DAF) and Filtration plants in a Direct Filtration (DF) mode. This involves turning off the DAF system and relying on Coagulation, Flocculation and Media Filtration for solids removal. A single day trial was undertaken to see how the plant would handle this mode of operation. The plant performance during this trial was good enough to enact a further three day trial and a week-long trial which both showed even more promising results.

The main components of this trial were:

• Will the plant perform?
• Will the savings justify the change?
• What is the operator time required?
• What other benefits or drawbacks are we missing?

The trial showed that there is a strong potential for significant cost savings that can be made at minimal interruption to normal operations. During DF mode the overall power demand is expected to reduce between 15-50% depending on the flow of the plant. There were also a number of other benefits including the potential to reduce sludge production and decrease machine wear that were not initially realised.

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Efficient and effective sludge management at the 4 ML/d Port Lincoln Wastewater Treatment Plant on South Australia’s west coast has encountered a number of challenges over the last six years. The original design involved treating waste activated sludge in four shallow sludge lagoons, filled sequentially and allowed to dry during summer. This was successful until increased plant loadings led to the lagoons becoming overloaded. A number of operating strategies have been employed to manage the lack of capacity with varied degrees of success including modifying wasting and sludge lagoon filling regimes; increasing aerobic sludge age; increasing operating height of lagoons; utilising biological additives; and providing lagoon mixing/aeration. A significant odour event in 2013 was managed with lime, magnesium hydroxide and caustic dosing; deodorisers; and mechanical desludging and dewatering. Most recently, Geobags have been employed as an alternative sludge destination. This paper will present the learnings from some of the various strategies employed and discuss future directions.

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In water industry, the value of process optimisation is well understood. However, there is a lack of suitable tools for operators and process specialists to conduct optimisation. Providing treatment professionals with such tools can be profoundly beneficial.

WTP Optimiser is a simple and handy tool that performs complex calculations relating to process optimisation. As these complex calculations are performed in the background, the user only sees the simple and user-friendly interface. A large number of complex and regular calculations can be performed by treatment professionals using WTP Optimiser in a fraction of time it would take to manually do these calculations. This tool also enables a rapid assessment of how changes to certain parameters can affect a treatment process. With WTP Optimiser, process related calculations are uniform, accurate, robust and reliable.

Using accurate and reliable data assists in making good operational and capital expenditure decisions that are reinforced by scientific principles. Further, WTP Optimiser improves record keeping for auditing purposes as calculations that provide the scientific basis for operational changes can be easily printed out or electronically stored. However, one of the biggest benefits of WTP Optimiser is the cost saving aspect as optimum process operations can cut down waste and make processes quite efficient.

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Concrete sewer assets are corroded in situ by acid produced in the sewer. Stricter pollution norms and changes in our dietary habits has increased rate of corrosion substantially over the last 2 decades.

Tens of billions of dollars worth of sewer assets in Australia are today under threat due to corrosion. Rehabilitation of these sewer assets will not only cost hundreds of millions of dollars but will also result in immense operational challenges.

One of the solutions to stop corrosion is by spraying Magnesium Hydroxide Liquid (MHL) on the surface of concrete sewers. Compared to exisiting corrosion protection technologies like plastic lining, MHL spray coating is 7 times cheaper over the life cycle of the asset and does not require flow diversion or man entry for application. This technology has been tested and used as a mainstream corrosion protection mechanism over the last 12 yrs in the USA and Australia.

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In the past many alarm systems have been implemented without any consideration to a holistic approach, and what we know now to be ill considered practices being implemented.

This approach has resulted in a vastly over-alarmed system which had been producing thousands of alarms per day. Poorly performing alarm systems have been cited across all Supervisory Control and Data Acquisition (SCADA) monitored systems as specific contributing factors in major incidents and adding significant operational costs as outlined in the Schneider Electric White Paper Titled “Alarm Management”.

The development of an alarm philosophy is seen as an important initial step in the journey to alarm management; essentially without the rule book there will be no structure to your management of alarms and often results in an ad hoc and inefficient approach.

The control system must be in a state of continuous improvement to consistently reduce the intervention of operational staff at a failure point. This presentation will delve into the journey that our Operational Management Centre (OMC) Staff are on to rationalize and optimize our SCADA System, the tools and processes which have been used.

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Portland, a town in the far South West of Victoria uses chlorine gas and the natural ammonia in the groundwater sourced from the Dilwyn Aquifer to achieve Chloramination (Total Chlorine) for its disinfection process. Portland has had low chlorine residuals in areas of the distribution system for many years. Monitoring of the distribution system had indicated that it was likely that biofilms had built up in a number of area’s within the network. The biofilms have the effect of using up the available chlorine thus resulting in the low residuals experienced within the network. It was decided to remove resistant biofilms from the network by dosing high concentrations of free chlorine a ‘burn’ into the network. The burn would kill the biofilms and therefore improve residuals across the entire network. This was the first chlorine burn attempted at Portland. The chlorine burn was carrried out over the summer months when water use is at its highest to try and achieve the change as quickly as possible without the need of flushing.

The burn was a success and Wannon Water was able to achieve a constant free chlorine residual throughout the entire network before reverting back to chloramination of the system. Once chloramination was resumed total chlorine residuals improved signifcantly across the entire system, confirming the success of the chlorine burn. The success of the burn reduced the chances of water quality issues like taste and odours as well as provide better protection from pathogens entering the system.

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Biosolids are produced at Waste Water Treatment Plants (WWTP) as a by-product of the waste water treatment process. The Victorian EPA “Guidelines for Environmental Management – Biosolids, Land Application” advises that biosolids should be viewed as a potential resource that can be beneficially utilised in the agricultural, horticultural and municipal sectors, rather than as a waste product requiring disposal.

To enable the use of biosolids, the EPA Guideline outlines the requirements from both a Treatment and Contaminant perspective. The uses for the biosolids are restricted depending on the level of treatment or amount of contaminants identified through sampling. Only biosolids with a T1/C1 classification are able to be used without restrictions.

As many biosolids are impacted by one or more metals leading to a C2 classification, this has caused a number of issues for water utilities to find ways to beneficially use the biosolids in an affordable and sustainable manner. As a result, there is an enormous amount of biosolids of varying qualities, stored in stockpiles at WWTPs while their owner looks for a sustainable use.

North East Water has been fortunate to be able to identify and then work in partnership with a local foundry that also has a waste product – sand used in the mould castings. This sand has been classified as inert and when blended with biosolids, produces a T1/C1 product. This is an exciting outcome for both organisations as two waste products have been able to be combined to form a new product now known as “Newsoil”, which meets the EPA Guidelines allowing unrestricted use. This paper describes the processes to verify the raw product and then post blending that are undertaken to achieve this outcome.

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Chemical addition in the water treatment plant is a critical process in the provision of safe drinking water. This process step presents the very real and often underrated risk of chemical overdosing in the water supply system.

This risk was highlighted to Barwon Water after two separate near misses involving chemical overdosing to the potable water supply. Barwon Water subsequently conducted investigations to establish the root cause of each event and developed and implemented control measures to eliminate each hazard.

Following this, a comprehensive chemical dosing system review was conducted at each water treatment plant to assess, establish and implement effective control measures to manage the risks presented by chemical addition at each site.

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In 2009 South Gippsland Water developed a Sustainability Strategy which has been driving the Corporation to reduce energy consumption, and investigate energy efficient options for many aspects of its operations. A significant contributor to power use at lagoon-based wastewater treatment plants are traditional surface aerators. Many of South Gippsland Water’s lagoon sites have aerators ranging in size from 12 to 37 kW which are maintenance and energy intensive.

The Inverloch wastewater treatment plant primary lagoon has a 12 kW diffuser aeration system, and two surface aerators which are 18 and 22 kW respectively. In July 2014, a Wind Mixer was installed in the primary lagoon with the aim of reducing the amount of time the 22 kW aerator would be required to operate. Since the installation of the wind mixer, South Gippsland Water has been able to switch the 22 kW aerator off for 5.5 months. A saving of $4500 (16% of energy costs) has been made for the nine month period July 2014 to March 2015 when compared to the same period the previous year. A payback period of approximately six years is anticipated as a result of these savings. Dissolved oxygen is closely monitored, and average dissolved oxygen concentrations have increased since the mixer was installed. This was the first Wind Mixer to be trialled in Victoria, and has proven to decrease energy consumption while having low maintenance costs.

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Nitrification causes a range of water quality issues in drinking water systems that utilise chloramine disinfection. A number of management processes can be implemented to prevent nitrification issues on a localised scale, however if these have not been effective there is the potential for the issue to spread throughout a supply system causing a widespread event. This paper outlines such an event in the Ballarat supply system and the successful mitigation techniques that were used to correct the problem. The benefits of conducting such a program are outlined together with the strategy that was applied.

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Approximately 80% of Geelong and the surrounding district’s water supply is sourced from the West Barwon Reservoir and diversions on the Wurdee Buloc Inlet Channel (WBIC). The WBIC transfers water from the West Barwon Reservoir to the Wurdee Buloc Reservoir and Treatment Plant. It consists of approximately 52 kilometres of earthen and concrete lined channel and five kilometres of syphons. Water is typically harvested during the period of May to December, necessitating visual inspections of the channel to identify any issues.

On the 8th October 2014, a steep section of the WBIC embankment slipped, rendering the channel inoperable. The failure was attributed to several factors but principally due to a blockage of a downstream trash rack. The blockage caused water to bank up and eventually overtop the channel, undermining the embankment.

The WBIC channel failure necessitated extensive works in order to return it to operation by May 2015. After detailed investigation, it was determined to pipe the affected and adjoining sections in lieu of repairing the open channel as this eliminated the failure mode.

The failure highlighted many WBIC operational improvement opportunities, which Barwon Water has consequently implemented. Actions include increased / improved remote monitoring of channel levels, greater automated controls, a review of trash rack operations and an optimised visual inspection program.

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Orica were the largest single consumer of drinking water in the lower Hunter, using over 4% per year of Hunter Water Corporation’s (Hunter Water’s) total water supply. Orica’s plant, which opened in 1969, uses the water as part of their ammonium nitrate production process.

Hunter Water have constructed an Advanced Water Treatment Plant (AWTP) as part of an Alliance contract, to significantly reduce the drinkingwater supply demands of Orica. The Kooragang Industrial Water Scheme was created with the Mayfield West AWTP at the centre. To deliver the required quantity and quality of effluent to the scheme, the Shortland WWTW underwent several upgrades.

Hunter Water engaged Veolia as the treatment operations contractor delivering Operation and Maintenance services for water and waste water treatment infrastructure in the region. The commissioning of the Mayfield West AWTP took place at the same time. This meant a change in people, leadership and potential loss of knowledge about the treatment process.

Despite taking over the plant operation at a critical time, the new operator was able to smoothly manage this transition. They recognised the need for wastewater expertise as part of the Mayfield West AWTP operation team, provided support to the operators and leveraged of the existing operations such as Fairfield AWTP to provide support and technical expertise.

Four months after Hunter Water awarded the contract to Veolia, the Mayfield West AWTP is proving to be successful by consitently producing suitable water quality and smooth operations.

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An incident occurred at one of Melbourne Water’s ultraviolet radiation (UV) disinfection plants in which a UV lamp and sleeve broke and fragments of quartz entered the water supply system. A burst in the reticulation pipework had caused a rapid change in flow and pressure through the duty UV chamber, resulting in UV lamp and sleeve breakage.

The UV plant is located alongside a 2100 mm conduit which transfers water between two major reservoirs. The UV plant gets its raw water from a 375 mm diameter main which tees off the conduit at the site, and flows through two parallel inline strainers into a pressure reducing station. The UV plant, consisting of three UV units, is then connected in parallel before the main continues to supply the township.

Melbourne Water has undertaken a root-cause analysis which identified a need for a surge analysis of the burst failure and a Computational Fluid Dynamics model to investigate the effect of the rapid change in flow and pressure on the UV lamp quartz sleeve. The model has confirmed the hydraulic scenario of the incident and the required mitigation measures for the future.

The key purpose of this paper is to increase awareness to this potential risk. The paper provides incident facts and a discussion on mitigation strategies that Melbourne Water is implementing.

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This paper is written a little ‘tongue in cheek’ and I hope it is taken with the light hearted spirit it has been intended. I would ask that you indulge me and try to recall your initiation into the industry or even your first job and enjoy this brief overview of my experience.

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The Cowes Recycled Water Treatment Plant (CRWTP) was commissioned early in 2012 utilising ultrafiltration (UF) membranes. Almost 3 years later the membranes were suffering an increased rate of failure during daily integrity tests. Initial investigations pointed to either an over exposure to chlorine during periods of preservation or prolonged periods of drying out of the membranes due to a leaking non return valve, again during periods of preservation.

This paper summarises the investigation and serves as a warning to other facilities to ensure that instrumentation, SCADA and procedures are in place to better protect this expensive infrastructure.

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The Bendigo Recycled Water Factory (BRWF) treats secondary-treated effluent from the Bendigo Water Reclamation Plant (BWRP) to a Class A standard using a range of processes, including tertiary filtration, through dual media filters. The BRWF was commissioned in 2008, prior to the introduction of the then Department of Health’s 2013 Guidelines for Validating Treatment Processes for Pathogen Reduction (the new Guidelines).

Coliban Water has completed a detailed gap analysis to identify potential gaps in meeting the requirements of the new Guidelines. The gap analysis identified a shortfall in pathogen Log Reduction Values (LRVs) to meet the new Guidelines. Coliban Water has implemented some upgrades and operational modifications to assess whether it can claim the required LRVs through the dual media filters. This paper discusses the outcomes of this performance review.

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In 2008 the Sariri Village was hit by cyclone Guba. The village is located on the North Coast of PNG, not far from the Kokoda trail with the nearest significant township being Popondetta. Sariri comprises around 7 tribes with approximately 300 inhabitants (expected to grow to 1000). When the cyclone hit, the village for all intent and purpose was erased from the map. The PNG government and tribal chiefs agreed to move the village from its existing river bank location to a safer site located approximately 2km inland. This move however created issues in relation to the most basic of water and sanitation needs.

In early 2014, Rotary Geelong approached Barwon Water seeking help on ways it could provide sanitation facilities along with safety and building skills to the village with the limited resources they had. Rotary had been active in PNG for many years and recently in rebuilding the Sariri village since cyclone Guba struck, but required help in relation to sanitation options.

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Constructed in 1926 as the first step towards modernising the sewage disposal system, the Ballarat South Waste Water Treatment Plant (BSWWTP) has been periodically augmented to cope with urban growth and development. Demand management and continued search for process improvement has triggered the need for major upgrades. These pose challenges to operational practice as new works are undertaken while effluent standards are not compromised.

The plant effluent is discharged to the Yarrowee River and is licensed to meet strict Environmental Protection Agency (EPA) regulations. Regular monitoring and reporting through National Association Testing Authorities (NATA) accredited laboratory’s confirms performance against operations. Lagoon based disinfection ensures pathogen reduction is achieved. More recent improvements across the primary secondary processes and sludge handling components combine the new and the old generating an exciting chapter in the history of waste water treatment at Central Highlands Water (CHW).

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However effective treatment processes are in eliminating contamination of drinking water they cannot totally eliminate the build-up of sediment and the formation of biofilms in the distribution system. Taste and odour issues can occur due to a build-up of biofilm and other events occur that can potentially affect reticulation water quality, including: burst mains, replacement works, deteriorating old mains, irregular tank cleaning programs and flow/pressure variations that all contribute to sediment build up, water discolouration and microbiological growth within supply systems. As the distribution system represents the final barrier before delivery of drinking water to consumers, it is important that there is adequate management of this system. The purpose of this work was to develop strategies for improving water quality in our distribution systems.

A number of strategies have been put in place or are in the process of being put in place to reduce the risks identified, however the optimisation of our distribution systems will be an ongoing process that develops and matures over time.

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The Safe Drinking Water Act 2003 (the Act) requires all water agencies (water storage managers and water suppliers) to develop, implement and review risk management plans in relation to safe drinking water. Specifically, under the Safe Drinking Water Regulations 2015, water suppliers must assess the risk that hazards pose to drinking water and determine if the current treatment processes can adequately remove those hazards. Every raw water source has unique characteristics which affects treatment plant operations. Likewise, each treatment plant has its own operating conditions and limits.

Case study examples and lessons learnt from other water agencies are valuable resources and education tools for the water industry to prevent similar occurrences elsewhere. Through the discussion of three real cases, issues are highlighted with regard to computerised plant control, reliance on automated alarms, and detailed system interactions.

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