Two major wastewater treatment plants, the Howard Street Treatment Plant and West Wodonga BNR Plant, previously serviced the township of Wodonga. West Wodonga BNR Plant treated the entire industrial load and approximately a quarter of the domestic load generated by the township of Wodonga. Howard Street Treatment Plant, an older trickling filter secondary standard plant located within the township itself, treated the rest of the domestic load. For various reasons a decision was made to close down the Howard St plant and divert all flows to West Wodonga.

This paper describes the history & background, the selection process – Authority’s expectations of an operating company, combining the old plant with the new, commissioning – hazop with site operators, introducing a site specific quality system, plant commissioning and why partnerships? It also describes the plant upgrade by PURAC in 2002/3 to provide advanced secondary treatment by Biological Nutrient Removal (BNR) process followed by UV disinfection. The plant also includes an advanced treatment process for production of high quality reclaimed effluent for re-use on and off site.

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Community and industrial concern regarding the potential health, environmental and safety risks associated with chlorine based disinfection has greatly increased over the past few years. The recent cryptosporidium scare in Sydney and the unprecedented political impact it has had on the Sydney Water Corporation has alerted the water industry to the potential consequences of any safety incident which can affect community health. Water boards have subsequently conducted risk assessments on all their operations concluding the “inherent risk” associated with the use of chlorine gas poses a potential safety concern.

Despite the outstanding safety record of the chlorine gas some water companies are considering converting their disinfection systems from chlorine gas to sodium hypochlorite due to the perceived safety benefit. The health risks associated with sodium hypochlorite, the increasing number of safety incidents occurring, the environmental damage from spills and the potential to greatly increase the cost of disinfection should be considered prior to conversion. This paper discusses the issues associated with the application of chlorine based disinfection products for water and waste water.

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The contractual requirement for manganese (Mn) at the White Swan and Lal Lal WTPs is 0.02mg/L, much lower than the ADWG or WHO guideline values. The drought has lead to highly variable raw water quality and to meet this challenging target a multifaceted strategy to provide rapid responses to changes in raw water quality has been adopted by United Water. These initiatives include monitoring of the reservoir column’s water temperatures and behaviour with on-line thermistor chains, depth sampling, assessment of various on-site Mn analysis methods, seeking rapid turnaround times for laboratory analysis and undertaking jar testing to determine appropriate potassium permanganate dose rates. The paper will describe the extent of the challenge, the pros and cons of each facet, and how they have been combined into a strategy that minimises Mn penetration into the Ballarat water supply.

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This paper highlights the process employed by Goulburn Valley Water (GVW) in the development of its electronic, web-based, operations and maintenance manuals. To date manuals have been developed for 40 water and 26 wastewater treatment plants along with over 200 sewer pump stations.

This paper will outline the history dictating the need for the Manuals, as well as the key processes undertaken during the development of the manuals including:

• GVW’s requirements.
• Developing a manual template and data management structure.
• Staff ownership.
• Data collection process from the facilities including operator input.
• Review process by operators and technical staff
• Ongoing review/update process including further development to allow users to access GVW’s Operational System.

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Water quality management has been frustrated by the appearance of various species of coliforms being detected in locations downstream of Disinfection treatment. Their presence has been attributed to many things including regrowth, ingress of contaminants via Fireplugs or faulty bird proofing of a Reservoir Roof, or occasionally, Disinfection Plant equipment failure. In any event, the finding of such, has led to the sometimes urgent requirement to treat the location in some form, generally by means of “spot dosing” with Sodium Hypochlorite. This Paper will discuss the means now in use by several large Water Authorities, to address this problem, using continuously on-line dosing units, deployed at various locations.

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The Black Rock Water Reclamation Plant was upgraded to secondary treatment in 1996. The upgrade included the construction of a sludge dewatering process. Until March 2001 the dewatered sludge was stored onsite at Black Rock in clay lined lagoons. Due to restrictions at the site it became necessary to find alternative storage sites.

Since March 2001 the dewatered sludge has been stored at Western Treatment Plant in Werribee approximately 62 kilometres away. In February 2004 a treatment process commenced to dry and stabilise the sludge into biosolids. The biosolids are now being reused beneficially as a soil improver on agricultural land. This process is an interim step toward Barwon Water’s long term biosolids management project.

The costs for transport and processing of the biosolids are based on the wet tonnage of the dewatered sludge produced. It is very important to ensure that the sludge dewatering operation produces the driest possible sludge cake. The paper discusses the problems faced by the operators of the plant, the solutions that were applied and the outcomes achieved.

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Traditionally, wet well cleaning has meant time-consuming hand held hosing and periodic entry to the wet well by maintenance personnel to facilitate physical removal of soils. More recently high volume, automatic water sprays have been used.

Whilst these approaches have proven effective there are a number of drawbacks, most notably:

• intensive labour requirement
• the OH&S implications of wet well entry
• high water consumption
• potential fouling of downstream sewers

A new and innovative approach to the problem of wet well cleaning has been developed in which a specially developed biological product is sprayed into the wet well. This new approach has proven highly effective and overcomes the drawbacks of conventional spray systems e.g.

• water consumption is reduced and
• there is no fouling of downstream sewers as the greases are degraded biologically

Capital costs are comparable to conventional spray systems and operating costs are offset through savings in labour. To illustrate these points a case study itemising capital, installation and operating costs and the results and savings achieved is presented.

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A central NSW regional water authority has historically experienced significant problems with odour and corrosion of concrete sewerage infrastructure. The severity of the problem was such that frequent odour complaints prompted attention from the NSW EPA. The sewerage network consists of around 1,385 km of rising and gravity mains and 182 pumping stations transferring approximately 40ML/day of sewage to two treatment plants. As a result of the undulating local topography, the network is characterised by frequent changes between rising main and gravity main. The continual rising and falling nature of the sewer lines resulted in the inability to maintain sufficient dissolved oxygen concentrations in gravity sections. As a result, vast sections of the network were effectively untreated. This prompted the water board to seek a solution for the control of effect of sewerage septicity.

Orica Watercare developed an odour mapping process of the sewerage network to establish a thorough understanding of the problem and the council’s requirements and ultimately a comprehensive control strategy. The implementation of Odourlock® dosing at 38 sites commenced in August 2002. Analysis at the main pumping station indicated a 95% reduction in hydrogen sulphide concentration. The reduction in H2S concentration coincided with a reduction in the number of odour complaints by 50%. Further, reduced H2S(g) levels within the network minimised corrosion of valuable sewerage infrastructure thereby decreasing the requirements for infrastructure maintenance and repair and hence costs.

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January 2003 saw some of the worst bushfires ever experienced in the North East of the State. The fires burnt for more than a month and burnt out an area of 1.1 million hectares. These fires caused major concerns for Authority staff in our Alpine region when the demand for water rose by up to five times normal consumption in some towns as people went about trying to protect their properties. On top of this our staff also had to protect our pump stations and treatment facilities so water would continue to flow into the reticulation system.

Staff members from other regions in the Authority were called in to assist in running a 24-hour roster, which was maintained for a few days until the threat had past. Once the flames were gone and we were left with a smoky haze and a charred landscape, our troubles were not all gone.

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The recently released Victorian Government White Paper, ‘Our Water Our Future: Securing Our Water Future Together’ features water recycling as a key component for delivery of sustainable water resource management in the urban environment. There is a significant emphasis on substituting drinking water with alternative water resources. One way of achieving this objective is to promote the use of dual pipe networks in new residential developments to deliver recycled water for non-potable uses such as garden watering and toilet flushing.

There are a number of residential dual pipe schemes operating in Australia and overseas. In NSW, the Rouse Hill development area has implemented a recycled water system for garden watering and toilet flushing. The City of St Petersburg in Florida, USA, is one of the best known reuse schemes, having been in operation since 1977. Other examples in the development stages include Mawson Lakes in South Australia and Pimpama Coomera in Queensland. In Victoria there are a number of apparently committed urban dual pipe schemes including Aurora Development in Epping North, Sandhurst and Eynesbury Estate. Schemes being investigated include developments at Cranbourne and Wyndham.

While recycled water should be viewed primarily as a valuable resource, potential microbiological and chemical risks have resulted in the use of recycled water being subject to strong regulatory oversight. Effective regulatory oversight is important to maintain community and industry confidence and thus support for recycling, ensure protection of health and the environment, encourage innovative approaches and provide stable frameworks for investment in recycling.

This paper discusses the potential contaminant issues that need to be considered and managed in establishing a dual pipe scheme. This paper also highlights the processes being undertaken to provide the regulatory oversight needed to facilitate residential dual pipe schemes.

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Forget the science with biosolids management – the biggest issue facing the Australian water industry is not the science; it is public perceptions and how the industry manages these perceptions.

By way of example, the USA had been “cruising” comfortably for a decade or more based on US EPA’s Part 503 (40 CFR Part 503), which was promulgated in 1993. Over the last five years, and particularly the last two, there has been a shift in public acceptance of land application of biosolids, the roles governing its application and the credibility of US EPA with respect to biosolids management.

There currently are some 40-50 separate legal and/or public challenges to land application of biosolids across the USA. There are also some very well coordinated, educated and briefed proponents objecting to land application of biosolids on a very wide scale.

Public perceptions of biosolids being a dangerous product are resulting in a flurry of activity within the USA water industry, driving the industry towards having to produce the highest quality biosolids regardless of the application. Local authorities with little qualifications in determining what is appropriate are placing significant restrictions and/or bans on land application of biosolids. The potential outcome for the USA water industry is billions of dollars of extra expenditure on biosolids management that has not been justified.

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Maintaining the pH in the delivery system within the Australian Drinking Water Guidelines (1996) has been one of the greatest challenges facing the operators of Greaves Creek Water Filtration Plant (WFP).

Following commissioning of Greaves Creek WFP in 1991 and the commencement of water quality testing in the system, the lack of pH buffering in the raw water source (alkalinity < 4.0mg/L) became a significant issue. The original lime dosing system at the plant was designed for pH control with little regard to alkalinity (buffering capacity). As a result, whilst the plant met process guidelines (pH 7.0-8.0), the low buffering capacity meant there was a significant increase in pH at the extremities of the distribution system.

A series of process changes and optimisation projects were initiated to improve the consistency of pH control and the pH buffering of the final water. By controlling the pH buffering capacity of final water at Greaves Creek WFP, there has been a significant reduction in the pH levels at the extremities of the supply system.

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A Feasibility Investigation has been carried out by City West Water and City of Melbourne, with the assistance of Earth Tech, to examine issues related to the implementation of a water mining project in the Carlton area of Melbourne to service the local parklands and other potential uses with recycled water. The investigation covered a wide spectrum of issues ranging from an assessment of demand for recycled water in the area to preparation of a Concept Design, including a Triple Bottom Line assessment, a risk analysis and an Environment Improvement Plan. The Investigation confirmed the feasibility of a Water Mining Project for the Princes Park Precinct and provided City West Water and City of Melbourne with the data required to facilitate internal and external planning and approval processes related to implementation of the Project.

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North East Water has undertaken a program to verify the West Wodonga Purification Plant (WWPP) capability to reliably produce Class A recycled water. The WWPP is a Biological Nutrient Removal plant with continuous backwashing sand filters and chlorine contact tanks that have been designed to provide Class A recycled water. This approval process will pave the way for many similar schemes across the state, and change the perception and increase the value of this water as a commodity.

The approval and verification process for the plant involved:

• Consultation with both the EPA and DHS;
• Incorporating principals from the Hazard Analysis Critical Control Point system (HACCP) by adapting the existing ISO9001 Quality Management System at the WWPP and;
• Conducting a plant verification trial.

The verification trial was conducted over an 8-week period to establish the minimum rate of pathogen reduction at critical control points in the treatment process. The results of this trial had demonstrated some linkage of pathogen reduction at critical control points to the surrogate parameters of chlorine and turbidity. Linkages of the surrogates to protozoa reduction were more difficult to establish due to issues with laboratory detection limits. It was found that the ability to monitor these surrogates in real time ensures that if water quality deviates significantly from set points, corrective action can be undertaken immediately, ensuring health targets are met.

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A trial of five water treatment interventions was proposed as a means to identify the cause of ongoing customer dissatisfaction with offensive taste episodes in the Sale water.

To assess the success or otherwise of the treatments, an untrained customer reference panel of 29 households was formed to provide feedback on their experiences with the water over a 3.5 month period. The selection and management of the group was developed and results indicate that the group could recognise different stages of the trial, including interventions that were successful in improving the aesthetic quality of the water. The panel also highlighted an unexpected difference between water sourced from different bores.

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This paper highlights the benefits gained from the development and use of trade waste management plans, in support of trade waste agreements. Specifically, the paper outlines four key components relating to the successful development and implementation of trade waste management plans, with an aim to achieving specific outcomes in cooperation with stakeholders. The principles of trade waste management plans are discussed in detail, including the individual steps involved with the successful development of “meaningful” trade waste management plans and monitoring of outcomes and benefits achieved as a result. Central Highlands Region Water Authority has had many successes as a result of its use of trade waste management plans. This paper discusses those experiences, along with lessons learned.

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