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Water Quality
How we treat and supply safe drinking water to our customers.
The source of your water
Most of the water treated by Lower Murray Water is drawn directly from the Murray River. The only exception is in the township of Kerang, where there are three water source options to chose from. These options are, water piped from the Murray River at Koondrook, an irrigation channel operated by Goulburn Murray Water, and the Loddon River at Kerang. The choice of where the water is drawn from is made after consideration of raw water quality and the level of demand.
The quality of the river water varies, sometimes significantly. It can vary at any time of the year, but in the Sunraysia area it can deteriorate in the summer months due to decreased flow and resultant increased algal growth.
Our treatment and supply systems
Sedimentation, coagulation & flocculation
Some particles will spontaneously settle out
from standing water (a process called sedimentation). When particles are slow to settle or are non-settling, chemicals (coagulants) such as alum are added to the water. These react with suspended particles in the water to form larger particles, called floc. During flocculation the floc particles develop to a larger size. The larger size and weight of the flocs then assists in the sedimentation process.
Flocculant aids, polyelectrolytes, are also commonly used to enhance the flocculation phase which then assists in the sedimentation process.
Filtration
Filtration occurs as the water passes through filters that help remove particles that have not settled in the sedimentation process. Sand filters are commonly used in the water treatment process. This process of sand filtration removes fine suspended solid matter as well as some other particles, such as larger micro-organisms. Filters can also be made of layers of sand, gravel and filter coal.
pH correction
Due to the addition of coagulants and chlorine, the pH of the water being treated is lowered, becoming more acidic. To inhibit corrosion and make the water safe to use, the pH is adjusted to a neutral pH, about pH 7.0, by adding lime or other alkaline chemicals such as soda ash or sodium hydroxide.
Disinfection
Water is disinfected to kill any pathogens (disease causing organisms) that may be present in the treated water and to prevent them from re-growing in the distribution systems. Without disinfection, the risk from waterborne disease is greatly increased.
Chlorination using gaseous chlorine is the most common form of disinfection used in the water treatment industry.
Fluoridation
The drinking water supplied from the Robinvale, Mildura, Mildura West Red Cliffs, Swan Hill & Kerang Water Treatment Plants(WTP's) has been fluoridated in line with the requirements of the Health (Fluoridation) Act 1973. The fluoride is dosed using two dosing systems (in line with the fluoride compound used to add fluoride into the water):
1. ‘Fluorodose’ process in which sodium fluoride is used to addfluoride to the water at Robinvale WTP. This system is used for small to medium installations to significantly reduce OH&S issues and improve ease of operation
2. Hydrofluorosilicic acid(HFSA)dosing system at the other WTP’s.Due to the OH & S implications associated with the handling of this chemical, Fluoride dosing is accomplished under very strictly controlled and monitored conditions.
Note: all Lower Murray Water water treatment plants are based on the coagulation, flocculation, sedimentation and Filtration processes except for the Red Cliffs plant which is a Dissolved Air Flotation Filtration (DAFF) plant in which the floc in the flocculated water is made to rise to the top of the flotation tank by the use of pressurised, air saturated water, which releases millions of extremely small air bubbles into the water being treated. The accumulated sludge is then periodically removed from the top of the flotation tank, as compared to the sedimentation process where the sludge accumulates at the bottom of the tank.
In order to supply safe potable water of an acceptable quality with respect to the aesthetic aspects i.e. clarity, taste, odour and pH, Lower Murray Water has water treatment plants providing full treatment for all our urban water supplies.
If blue green algae is present in the raw water, powdered activated carbon can be used during the treatment process to remove algal byproducts that produce taste and odour problems, and any toxins if present.
Non potable (untreated) water supplies
A requirement of the Safe Water Drinking Act is to ensure that customers and visitors to areas receiving non potable water understand that it is untreated and therefore not suitable for consumption.
In response to this requirement Lower Murray Water has produced a pamphlet titled ‘Living with an Untreated Water Supply’. The pamphlet cautions that untreated water is not fit for such things as drinking, food preparation or cleaning teeth it also advises customers to take care when bathing and showering.
The pamphlet is mailed to the residents of small townships, which are connected to a Lower Murray Water untreated water supply. The pamphlet is also sent to all customers in the Lower Murray Water irrigation districts and private diverters in the area from Nyah to the SA border who take delivery of untreated water. The pamphlet will be sent out every two years to our untreated water supply customers
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Brochures and diagrams
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Blue Green Algae fact sheet (PDF) |
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Lower Murray Water drinking water Policy (PDF) |
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Living with untreated water (PDF) |
Annual Drinking Water Quality Reports - All Supplies
Drinking Water Quality Reports
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Sunraysia Area (PDF) |
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Swan Hill Area (PDF) |
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Robinvale Area (PDF) |
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Kerang Area (PDF) |
Raw Water E Coli Report
Treatment Plants
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Cities/township serviced |
Kerang
Koondrook
Mildura & Mildura West
Murrabit
Piangil
Red Cliffs
Robinvale
Swan Hill
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Kerang
Koondrook
Irymple, Merbein, Mildura, Nichols Point, Cabarita, Kings Billabong, Mildura South, Irymple, Merbein, Mildura
Murrabit
Piangil
Red Cliffs
Robinvale
Lake Boga, Nyah, Nyah West, Swan Hill, Woorinen South |
Water Quality Standard
The water quality must also meet the requirements of the Safe Drinking Water Act 2003 (SDWA)
All of our treatment plants treat the water to comply with the Australian Drinking Water Guidelines 2004 (ADWG), which is the standard required by the Victorian Government.
Monitoring and Testing
We monitor our water to ensure that the water delivered to our customers meets ADWG guidelines and the SDWA. Samples are collected as water leaves the treatment plants, and at customer taps, in accordance with the requirements of the SDWA. An independent laboratory that is accredited by the National Association of Testing Authorities (NATA) and approved by the Department of Human Services, tests the water samples.
Types of testing:
Microbiological tests
Water is tested to ensure that it is free from micro organisms that can cause disease. These tests measure the presence of E.Coli and the total number of coliforms, or bacteria, which indicate possible contamination from sources such as human or animal waste.
Tests are also conducted for Cryptosphoridium or Giardia.
Physical and Chemical Tests
The physical characteristics of water relate to its appearance, taste, odour and ‘feel’, as well as the corrosion or scaling potential of the water. Physical tests conducted include tests for colour, turbidity and pH. The pH, is a measure of whether the water is acidic or basic. A pH of 7 is neutral. Turbidity is a measure of the number of particles present in the water, thus high turbidity causes a cloudy appearance.
Chemical tests are conducted for a range of substances, including chlorine, and disinfection by-products and aluminium. These tests indicate the presence of substances that may be naturally occurring or added to the water during the treatment process for health or aesthetic purposes. Tests for a range of health related inorganic and organic components as well as pesticides/herbicides are also undertaken.
Risk Management
A drinking water quality management plan encompassing Hazard Analysis and Critical Control Points (HACCP), is in place for all Lower Murray Water urban supplies. HACCP is an internationally recognised system that identifies and manages significant risks at key points in the water production process.
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