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Wastewater (Sewage) Treatment Process
Lower Murray Water operates ten sewage treatment plants, and associated sewerage systems.The sewerage system is made up of the pipes, pump stations, treatment plant and equipment etc required to collect, transport, treat and dispose of the sewage. The transport system consists of small pipes that join into increasingly larger ones, eventually becoming the 'mains' entering the treatment plant. The treatment plant treats the sewage to a standard whereby it can be reused or recycled in an environmentally safe and sustainable manner, under licence to the Environment Protection Authority.
The wastewater is treated at the treatment plant by two basic processes, pre/primary treatment consisting of the separation of screenable and settleable solids and then secondary treatment whereby microorganisms break down the organic matter in the wastewater to a stage where it can then be disposed of in a environmentally sustainable and beneficial manner. There are many types of treatment plants, some consisting of mechanical operations that supply oxygen to the microorganisms to speed up the breakdown of the organic matter in the wastewater. These types of plants require a relatively small 'foot print' and are used in areas where large areas of land are not available and where environmental conditions may not suit the operation of lagoon based systems.
Lagoon based systems require relatively large areas of land. In this type of treatment the breakdown of the wastewater occurs by natural microbial processes without the need for aerators to supply oxygen mechanically.The process is therefore relatively slow compared to the mechanical types of plants alluded to above, but are more economical and easier to operate and maintain.
LMW Wastewater Treatment Plants
Kerang WWTP - is a lagoon based treatment plant, servicing a population of approximately 4,000.The treated wastewater is recycled back into the water cycle by evaporation.
Koondrook WWTP - is a lagoon based treatment plant, servicing a population of approximately 850. The treated wastewater from this plant will be reused on-site for pasture/fodder production.
Koorlong WWTP - this plant services approximately one third of the Mildura residential area, the township of Irymple, including major trade waste from this area, and trade waste from a fruit and vegetable processing operation in Merbein. The plant serves a population of approximately 11,000 as well as the trade waste.The treatment plant process is based on the Sequencing Batch Reactor activated sludge process, followed by UV disinfection. The class C reclaimed water from the process is sold to a third party for reuse in the irrigation of high value horticultural crops.
Lake Boga WWTP- is a lagoon based treatment plant, servicing a population of 700. The treated wastewater is recycled back into the water cycle by evaporation.
Merbein WWTP - is a lagoon based treatment plant, servicing a population of approximately 1,800. The treated wastewater is recycled back into the water cycle by evaporation.
Mildura WWTP - this is a extended aeration activated sludge plant based on the carrousel system, servicing a population of approximately 17,000. All the treated wastewater is reused on site irrigating both pasture and tree plantations.
Murrabit WWTP - is a lagoon based treatment plant, servicing a population of approximately 100. The treated wastewater is reused irrigating the Murrabit recreation reserve.
Nyah West WWTP - is a lagoon based treatment plant, servicing the townships of Nyah and Nyah West with a combined population of approximately 885. The treated wastewater is recycled back into the water cycle by evaporation.
Robinvale WWTP - is a lagoon based treatment plant, servicing a population of approximately 1,800. The treated wastewater is reused on-site irrigating lucerne.
Swan Hill WWTP - is a lagoon based treatment plant, servicing a population of approximately 10,000. The treated wastewater is recycled back into the water cycle by evaporation.
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Trade Waste
Trade Waste is any industrial or commercial wastewater discharged to sewer, other than normal domestic sewage. LMW's trade waste policy is administered/controlled by LMW's Trade Waste By-Law No 4.
Only trade waste which complies with specific guidelines is acceptable for discharge to the sewerage system. Lower Murray Water accepts a variety of industrial and commercial trade wastes that comply with the guidelines.
There are two main categories of trade waste:
1) Minor trade waste - such as that emanating from hotels, restaurants, take away food businesses, laundrettes, car wash's etc which discharge relatively small volumes of wastewater to sewer. These businesses are issued with a 'Consent to Discharge Trade Waste', if if they meet LMW's requirements, and are charged an annual fee which is incorporated into LMW's quarterly tariff notice.
2) Major trade waste - comprising customers such as fruit and vegetable processing, fruit packing and winery operations which discharge large volumes of wastewater to sewer, generally greater than 1000 kL per annum. These customers are required to sign a Trade Waste Agreement with LMW and are charged on a quarterly basis, the charge being based on the organic, suspended solids, and hydraulic loadings discharged by the customer.
Both categories of customers must have appropriate pre treatment facilities in place to treat the wastewater to a standard which meets LMW's guidelines. Theymust also have, in the case of minor trade waste, a ‘Consent to Discharge Trade Waste to the Corporation’s Sewer’ or in the case of major trade waste customers, a ‘Trade Waste Agreement’ with the Corporation.
Please contact Lower Murray Water for further information regarding the trade waste ‘Consent to Discharge’ for minor trade waste or an Agreement for major trade waste.
Trade Waste Acceptance Conditions Link (15/07/11)
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