Why do source waters need treatment?
Water is not taken from sources that are highly polluted, and water for drinking is drawn only from good quality surface and ground water. But all water must still be treated before it is safe to drink. Contaminants can come from agriculture or industry. They may, for example, include treated sewage effluents, and traces of agriculture chemicals in areas where farming is practised. All sources are disinfected to kill germs, known scientifically as pathogens, which may have entered water sources from human or animal wastes. image of a water cycle diagram Ground waters are usually of higher quality than surface sources. However, they can contain traces of agricultural chemicals and a few may contain toxic chemicals, which occur naturally in some aquifers. Waters in large lakes or storage reservoirs undergo a natural purification stage – factors such as sunlight help eliminate pathogens naturally. These waters are usually retained for up to six months before being treated.
Water is not taken from sources that are highly polluted, and water for drinking is drawn only from good quality surface and ground water. But all water must still be treated before it is safe to drink. Contaminants can come from agriculture or industry. They may, for example, include treated sewage effluents, and traces of agriculture chemicals in areas where farming is practised. All sources are disinfected to kill germs, known scientifically as pathogens, which may have entered water sources from human or animal wastes. Ground waters are usually of higher quality than surface sources. However, they can contain traces of agricultural chemicals and a few may contain toxic chemicals, which occur naturally in some aquifers. Waters in large lakes or storage reservoirs undergo a natural purification stage – factors such as sunlight help eliminate pathogens naturally. These waters are usually retained for up to six months before being treated.
