The Trentham Water Treatment Plant combines a unique combination of Continuous Microfiltration (CMF) , Ozone and Granular Activated Carbon to treat a variable and difficult raw water supply. Whilst standby chemical coagulant dosing is installed at Trentham, it has not been used since commissioning in February 1998. Without chemical coagulant addition the treated water quality from the plant has exceeded all Coliban Water’s performance criteria. The combination of technologies has presented some interesting outcomes from an operational point of view. These include the biological management of the activated carbon and management of backwash flows.

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This paper discusses the methods and current practices for improving the management of drinking water quality by water authorities. These methods include risk assessment and the application of alternative principles of management, such as AS4360 (Risk Management), and Hazard Analysis and Critical Control Points (HACCP). HACCP principles have been widely adopted in the food industry and are currently being assessed by the World Health Organisation and the Australian water industry for relevance to drinking water quality management.

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North East Region Water Authority is in the process of establishing and maintaining a best practice Environmental Management System. This paper outlines the framework of NERWA’s EMS, discusses the planning, development and implementation stages of the EMS.

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The purpose of this paper is to discuss the commissioning of the chlorination and dechlorination systems for the Shortland Wastewater Treatment Plant. It points out the problems as they occurred and the effective action required to remedy the problems. The reason for writing this paper is to pass onto the AWWOA Hunter Water Corporation’s experience so to assist other operators in solving similar problems.

The Hunter Water Corporation provides water and sewerage services to approximately 420,000 people in the Newcastle area (which is 2 hours drive north of Sydney). The Corporation operates twenty-one (21) wastewater treatment plants (WWTP’s) which treat sewage from residential, commercial and industrial customers. They range in size from small local plants treating sewage from a few hundred households to large automatic plants capable of processing sewage for over 200,00 people.

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Two major wastewater treatment plants, the Howard Street Treatment Plant and West Wodonga BNR Plant, currently service the township of Wodonga. West Wodonga BNR Plant treats 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, treats 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.

The nominal capacity of the West Wodonga BNR plant is exceeded under existing loading conditions, and with the continued tightening of EPA requirements on effluent quality and the increased load expected from Howard St Plant before 2001, a significant upgrade of the West Wodonga Plant is required immediately. This paper describes the current as well as the future operating conditions at the plant and also outlines the upgrade strategy developed and adopted for implementation.

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North East Region Water Authority (NERWA) has signed a Memorandum of Understanding (MoU) with the Victorian Government that includes a requirement to provide drinking water supplies that meet World Health Organisation (WHO) guidelines (1984). Complying with the microbiological parameters (faecal coliforms and coliforms) means that drinking water supplies must be disinfected.

Traditionally, chlorination has been the preferred method for disinfecting water supplies because it is an effective disinfectant, both initially and as a residual, and because it is inexpensive. However, several North East Victorian communities accustomed to drinking untreated water supplies are generally opposed to disinfection by chlorination. In these cases, NERWA has consulted with community groups to install various alternative means of disinfection including ozonation, ultraviolet irradiation and chlorine dioxide systems. This paper discusses the process involved in selecting the disinfection methods with the community, briefly describes the disinfection process selected, and discusses the challenges involved in commissioning the new Ozone/GAC/UV plant at Myrtleford, the first of its kind in Australia.

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Confined space entries have always been part of maintenance work on water and wastewater systems. Many tragic accidents have occurred due to a lack of understanding of the hazards in such environments. In recent years, the introduction of stringent new regulations has enforced the application of safe systems of work for these activities in the Water Industry. These requirements have also encouraged the development of new designs and workplace trends, which enable work to be undertaken without the need for personnel entry into these spaces. This study documents the new regulation together with some of these trends and initiatives, which are now being practiced in the water industry.

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South East Water won an Australian Quality Award for Business Excellence from the Australian Quality Council based on seven categories of business performance; one of these categories is Information and Analysis. This paper deals with measures South East Water took in improving the collection of information from waste water plants and the application of that data to improve treatment plant management. The concept is based on lead and lag indicators. Lead indicators tell what is happening now and are an immediate measurement, lag indicators tell what has happened and what the end result is. In Treatment Plants clearly the lead indicators are the process stream internal monitoring measurements and the lag indicators the EPA license testing. In simple terms it is the daily test and flow recording performed by the operator and the result of samples sent to NATA laboratories.

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In August 1999 the Commonwealth Scientific and Industrial Research Organisation (CSIRO) will publish Australia’s first comprehensive guideline for the sustainable planning, design and management of effluent-irrigated plantations entitled: Sustainable Effluent-Irrigated Plantations: An Australian Guideline written by B.J. Myers, R.G. Benyon, W.J. Bond, R.A. Falkiner, P.J. Polglase, C.J. Smith, V.O. Snow, and S. Theiveyanathan. The guideline represents the culmination and final output of a major multi-disciplinary 7-year research effort – the Wagga Wagga Effluent Plantation Project.

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This paper illustrates, through a worked example, how planners can work with operators to expand the options considered when confronted with a problem. South East Water Limited (SEWL) had to increase the storage available at one of its sewerage pump stations to meet the minimum storage time required to get emergency response teams to rectify problems.

By involving operations staff, the number of options to provide contingency storage expanded from one to eight. The initial option was to construct three concrete contingency tanks at a cost of approximately $470 000. After collaboration between planning and operators, an innovative solution combining conversion of existing wet and dry wells together with the utilisation of the available storage capacity at the upstream Pump Station was adopted at a total cost of $50 000. This example illustrates how rethinking problems can often produce more economic solutions.

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This paper discusses a variety of methods used for the measurement of flow rates in open channels. It examines the principal of measuring flow using a primary device, or calibrated flow restriction, paired with a level sensor. The various types of level sensing techniques used including ultrasonic, bubbler and pressure transducer are explained and the installations most suited to each technique discussed.

The paper then examines the “Area Velocity Measuring Technique” which utilises a Doppler velocity probe paired with one of the standard level measuring techniques to measure flow in open channels which don’t have a primary device located in them.

The paper closes with an examination of how a number of difficult applications may be overcome and how recent advances in flow measuring devices are helping to solve these applications and overcome other problems with existing systems.

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A strategy designed to ensure that an existing dam continues to perform effectively will include:

• a set of operating instructions.
• maintenance of the reservoir components.
• an ongoing review of structural performance.
• a system to indicate the appropriate application of resources.
• the ability to respond to an incident.

This paper will explore each of these issues and how they may be applied to dams in a variety of situations. These situations include water supply reservoirs, flood retarding basins, levees and wastewater lagoons. While each situation is different, the underlying principles will remain consistent. The range of situations encountered by Victorian Water Authorities provides the inspiration for the development of an efficient approach to the management of the safety of dams.

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Qualitative and quantitative trials were conducted on a newly developed wastewater treatment system. The system, called the Clarke IC-SEP (Induced Cyclonic Separator), works by air flotation, and as such was compared to traditional DAF (Dissolved Air Flotation) systems. These initial trials show that the IC-SEP can remove solids and other contaminants from waste and product streams much more efficiently than DAF systems. For a wide range of phase separation operations, the IC-SEP has displayed significant cost savings, which is of substantial interest all industries.

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EPA’s Industrial Waste Strategy Zeroing in on Waste released in 1998 challenges Victorian industry to change the way it thinks about its wastes. It encourages industry to adopt more creative ways of avoiding the generation of wastes at source and where wastes cannot be avoided, it encourages industry to pursue more economically and environmentally beneficial opportunities to return wastes to resources through reuse, recycling or recovery of energy.

For the water industry this effectively means effluent and sludge, by-products of sewage treatment, should be viewed as resources to be reused in a beneficial and sustainable manner, rather than wastes requiring disposal. The reuse of these materials involves treating them to a level appropriate for their intended reuse application, and using the resulting water (termed reclaimed water) or sludge (termed biosolds) in a sustainable manner for a beneficial purpose. Beneficial reuse is defined as the sustainable use of reclaimed water or biosolids in a manner which provides some direct or indirect economic, social or environmental value, while still protecting the environment, public and agricultural (being stock and plant) health.

The concept of beneficial reuse is different from that of wastewater disposal to land. The primary purpose of land disposal is to discharge waste to land in a controlled manner so as not to cause pollution. In contrast, the primary purpose of beneficial reuse is to use what was previously considered “wastewater or sludge” as a resource in a beneficial and safe manner.

The Environment Protection Authority (EPA) is working with the water industry to facilitate this conceptual change in thinking. EPA has facilitated this change through the development of Best Practice Environmental Management Guidelines (BPEMGs) for the reuse of reclaimed water and biosolids. The specific titles are Best Practice Environmental Management Guidelines for the Use of Reclaimed Water and the proposed Best Practice Environmental Guidelines for Biosolids Management respectively.

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When wastewater plants were first constructed in the early 1900’s, the design criteria was make the effluent look better. More recently, particularly in the last decade, stringent quality standards are being applied to plant effluent, whether by regulatory authorities or environmentally concerned plant management. More often than not now, limits on nitrates, ammonia, phosphates, suspended solids, etc are applied to outfalls. The wastewater not only has to look good, it must also be good.

This in turn has caused operators to turn their focus to the biological activity in a treatment plant, particularly in the aeration basin (in conventional plants) or the SBR (sequential batch reactor). Two critical parameters in these tanks are Dissolved Oxygen and Suspended Solids. This paper aims to discuss why these measurements are needed to ensure that the process is optimised and how to apply the sensors so they remain accurate and reliable.

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