Water testing is almost always used to see what the problems are. When testing the water, it is important to think about the range of water conditions that may occur. What land use, activities or situations can affect the water quality? Some examples of activities that can have an intermittent effect on water quality are rainfall, land slips, excavation, tree felling and cows crossing streams. The should be tested at the times when the quality is poor (and needs more treatment), and also under normal conditions. The most common treatment is disinfection. Most water suppliers add chlorine or another disinfectant to kill bacteria and viruses. Other treatment might also be needed, according to the quality of the source water. Table 3 indicates the treatment that may be needed for various contaminants. Only common contaminants are shown. The need for treatment will depend on their concentration. Table 3: Treatment needed for various water contaminants Contaminant Description Sources Likely treatment methods Micro-organisms Bacteria Bacteria are a type of Disease-causing Bacteria are usually killed contaminant, some bacteria from farm by dosing with chlorine. of which are capable of animals, birds, This has the advantage of causing waterborne disease. possums, sewage remaining in the water as Bacteria are very small. discharges, treated protection against They cannot be seen with the effluent. recontamination. naked eye. They are Also backflow and Some other chemicals are capable of multiplying quickly recontamination effective but are less and are responsible for such in the network. common. Sometimes UV waterborne diseases as light is used. cholera, typhoid and Other methods are campylobacteriosis or boiling, and physical symptoms of gastroenteritis. removal (eg, reverse osmosis). Viruses A virus is an extremely small Viruses are usually Human particle capable of causing controlled by dosing with waterborne disease. chlorine. This has the sewage Disease-causing viruses that advantage of remaining in treated are capable of being the as protection Also transmitted through water against recontamination. other include hepatitis A and Some chemicals are poliomyelitis. the effective but less common. Sometimes UV light is used, but it is not very effective against some viruses.
Water testing is almost always used to see what the problems are. When testing the water, it is important to think about the range of water conditions that may occur. What land use, activities or situations can affect the water quality? Some examples of activities that can have an intermittent effect on water quality are rainfall, land slips, excavation, tree felling and cows crossing streams. The should be tested at the times when the quality is poor (and needs more treatment), and also under normal conditions. The most common treatment is disinfection. Most water suppliers add chlorine or another disinfectant to kill bacteria and viruses. Other treatment might also be needed, according to the quality of the source water. Table 3 indicates the treatment that may be needed for various contaminants. Only common contaminants are shown. The need for treatment will depend on their concentration. Table 3: Treatment needed for various water contaminants Contaminant Description Sources Likely treatment methods Micro-organisms Bacteria Bacteria are a type of contaminant, some of which are capable of causing waterborne disease. Bacteria are very small. They cannot be seen with the naked eye. They are capable of multiplying quickly and are responsible for such waterborne diseases as cholera, typhoid and campylobacteriosis or symptoms of gastroenteritis. Disease-causing bacteria from farm animals, birds, possums, sewage discharges, treated effluent. Also backflow and recontamination in the network. Bacteria are usually killed by dosing with chlorine. This has the advantage of remaining in the water as protection against recontamination. Some other chemicals are effective but are less common. Sometimes UV light is used. Other methods are boiling, and physical removal (eg, reverse osmosis). Viruses A virus is an extremely small particle capable of causing waterborne disease. Disease-causing viruses that are capable of being transmitted through water include hepatitis A and poliomyelitis. Human sewage treated Also other the Viruses are usually controlled by dosing with chlorine. This has the advantage of remaining in the as protection against recontamination. Some chemicals are effective but less common. Sometimes UV light is used, but it is not very effective against some viruses.
treatment-options-small-drinking-water-supplies-jan14.docx