Water in dams (and rivers) is called raw water, and contains a lot of dust, dirt and decomposing leaves. Before we can use the water, this material must be removed. At the water treatment plant on Mount Kynoch the dirt particles are removed through processes of flocculation and filtration. Even the fine particles are removed - they are made to join into large clumps that will be heavy enough to sink. The flocculation process uses a coagulant mixed in the water to cause this to happen. The coagulant itself is removed from the water following this process.
Raw water also contains many kinds of living organisms such as tiny plants and animals and bacteria. Most bacteria are harmless, but there are some - the pathogenic types - which can cause illness in humans. These bacteria can be removed by various treatment processes, including chlorination.
Bore water (also called groundwater) comes from rain which has seeped down through rock layers in the ground into the aquifers, or cavities, in the rocks. Some of this water comes from a long way underground - Toowoomba's twenty bores range between 30m-100m deep into the basalt aquifer.
Groundwater goes through a natural filtering process as it seeps through the rocks. Sometimes it picks up high levels of minerals which cause it to become 'hard'. If water is hard it will not lather well so some of our water is made 'soft', or easy to lather, by passing it through special filters. Bore water is chlorinated before passing into the water reticulation system to ensure it is free of any harmful bacteria that may have entered it after it is pumped from underground.
Chlorination of water
Safe drinking water is vital for our health. Water from storage dams and catchment areas contains potentially harmful micro-organisms which can cause serious illness or even death. Organic material and larger micro-organisms in raw water are removed at the Mt Kynoch Water Treatment Plant by coagulation, flocculation and filtration. However, some pathogens are not eliminated through these treatments. Therefore, after filtration, chlorine is added to the water to kill the harmful micro-organisms that might be present in the water and also to stop them from regrowing in the distribution system. Contact time for the chlorine disinfection process is provided in storage tanks at the Water Treatment Plant and also at various other locations throughout the water distribution system.Chlorine has been used to disinfect drinking water supplies for more than 100 years. As a result, water borne diseases like cholera, dysentery and typhoid have been controlled. Chlorine is a simple, reliable, effective and safe way to treat drinking water against contamination by micro-organisms. Once treated, a small residual amount of chlorine remains in the water to provide continuing protection from micro-organisms until the water is delivered to your tap.
What if you can taste or smell chlorine in your drinking water?
The water is safe to drink. The smell will disappear simply by leaving a jug of water uncovered in the fridge for a short period of time.More detailed information about the water treatment process is produced in some of our educational brochures which can be obtained by contacting us.