How does it work?
We treat water in various ways. The treatment method depends on where the water has come from – we refer to this as the ‘system of supply’.
Depending on the system of supply, water will have undergone varying degrees of treatment, ranging from no treatment in regulated supplies, to full treatment via a water treatment plant.
After treatment, all water is reticulated through storage tanks and pipes before it’s delivered to our customers.
What types of treatment do we use?
Find out more about the different types of treatment we use below.
All drinking water we supply is disinfected to ensure that micro organisms are eliminated. We use three types of disinfection methods – Chlorination, Chloramination and Ultraviolet (UV).
A fourth type of disinfection also occurs naturally via exposure of raw water to ultra-violet radiation (sunlight) in raw water storages.
Coagulation and flocculation is a process where a controlled dose of chemical coagulant is added to the water. This makes any fine particles join together and form larger particles (floc) that can be settled or filtered from the water during the clarification stage.
Sedimentation of large particles happens during water storage in the reservoirs and basins upstream of our treatment plants.
Clarification is used to remove the remaining particles. This can be achieved by simply allowing the solids to settle to the bottom of a sediment tank. Or, can be achieved by using a mechanical process to separate the floc (large particles) from the clear water.
Chemical coagulants and/or flocculants are used to help the Clarification process.
When the source water is from an aquifer, the water may need to be cooled and/or treated to remove minerals such as iron.
Cooling towers allow heat to be transferred from the hot bore water to the air. Fans then draw in fresh air to allow heat exchange to be maintained by avoiding an equilibrium being established, whilst a honeycomb structure is used to increase the contact between the air and water. Iron removal is achieved when aeration causes soluble iron to oxidise and precipitate out. The particulate iron is then removed by either settling or filtration.
Water is passed through a filter consisting of several types of graded filter media to remove remaining particles. Filtration is also effective in removing harmful pathogens such as Giardia and Cryptosporidium.
At regular intervals each filter is backwashed to remove trapped particles from the filter media and to maintain filter integrity and water quality.
The adjustment of pH level is conducted to make coagulation and disinfection more effective, or to reduce the corrosiveness of the water. pH can be adjusted by adding acidic or alkaline solutions to the water. We currently use carbon dioxide, caustic soda, soda ash and hydrated lime to adjust pH.
Sequestration involves the addition of sequestering agents followed by chlorination which keeps dissolved iron and manganese from oxidising and precipitating.
Iron sorption filters remove arsenic by adsorption. Adsorption is a process where arsenic is attached to the surface of the iron sorption filter media that contain a large surface area.
Iron sorption is used as a polishing step to remove any residual amount of arsenic left in the water.
Oxidation is a process of converting a substance from a lower oxidation state to a higher oxidation state. Oxidation often results in soluble minerals becoming non-soluble.
As a result of minerals becoming non-soluble, they settle out of the water. Minerals such as arsenic and manganese need to be oxidised to be removed by clarification and filtration processes.
Oxidising can occur naturally by aeration or chemically by adding chlorine or other oxidising agents such as ozone and potassium permanganate.
We add fluoride to our drinking water to prevent dental decay. This is directed by the Victorian Government and endorsed by the National Health and Medical Research Council (NHMRC).
The addition of fluoride to our drinking water is carefully controlled and monitored. It doesn’t change its taste, smell or colour.
Fluoride is added to an optimum dosage of one part per million (1 milligram per litre), as required by the NHMRC.
- Water supplies in Warrnambool, Allansford, Koroit, Hamilton, Dunkeld, Tarrington, Camperdown, Lismore, Derrinallum and along the Camperdown rural pipeline all have fluoride added.
- The Victorian Department of Health has directed us to fluoridate the water at the Terang Water Treatment Plant (WTP). This means Terang WTP customers (Terang, Noorat, Glenormiston and Mortlake) can expect to receive fluoridated water in 2024.
- The bore water in Portland and Port Fairy contains naturally occurring fluoride.
- Other supply areas are not currently connected to a fluoridated supply.
More information about water fluoridation is available from the Victorian Department of Health website.
Find out about your local supply
Learn more about your local water supply and download our information sheets for your area.
