Bacteria & Viruses

	Bacteria (Coliforms & E. Coli) Coliform bacteria grow in the intestines of human beings and other warm-blooded animals. Their presence in a water sample is an indication of human sewage or animal waste. Coliforms are a reliable measure of contamination and indicate the presence of specific contaminating organisms. Analytical tests count the number of coliform bacteria present in a sample and use that as a basis for other bacteria present. The Canadian Drinking Water Guidelines limit the maximum number of coliforms in a 100 mg sample of water to less than one. As with nitrates, the best solution is to eliminate the problem. A properly constructed well with protection from run-off should be constructed. If the source of the problem cannot be determined, then treatment may be necessary.All bacteria are sensitive to the temperature and pH of water. Some bacteria can tolerate acid water, but for the most part, bacteria thrive in water with a pH between 6.5 and 7.5 -- neutral waters. As for temperature, most bacteria thrive in water that is body temperature. Chlorination is the most common disinfection method. A chlorine injection system can effectively destroy many types of pathogens. It involves a pump that injects chlorine into the water that is held in a retention tank for a specific length of time. Contact time is determined by the many variables of water -- pH, iron content, hardness and other factors. As well, the dosage of chlorine must be determined so that enough residual remains to disinfect the water supply from source to point-of-use. A carbon filter can be used to filter the chlorine out of the drinking water. Ultraviolet disinfection systems like the Trojan UV Max Systems are especially effective for commercial and residential use. Ultraviolet light destroys the pathogens without adding taste or odour to the water. Many municipalities are now experimenting with the use of ultraviolet disinfection so as to reduce the amount of chlorine and chloramines added to public drinking water. Because no taste or odour is added and whole-house systems are extremely affordable, ultraviolet disinfection is becoming the method of choice to remove bacteria.
	Viruses Viruses are capable of causing disease in both plants and animals. They can often pass through porcelain filters that are capable of screening bacteria. Viruses produce such diseases as infectious hepatitis. An absolute micron filter can be effective to remove some viruses. Ultraviolet disinfection is the ultimate treatment for DNA disruption of viruses. An ultraviolet system destroys the virus so that it can no longer cause disease.
	Cryptosporidium/Giardi/Protozoa - Cysts Protozoa are one-celled organisms that live in water. Cysts can be classed as either helpful or injurious. Non-disease producing protozoa can give water a fishy taste and odour. The harmful protozoa are cysts that carry water-borne disease such as, amoebic dysentery. These cysts can be resistant to ultraviolet and chlorine, but can be removed with a 1-micron filtration. Fortunately, cysts are much larger than bacteria and can be removed with fine filtration. Cryptosporidium and giardi are waterborne protozoan that form cysts. They cause acute gastrointestinal distress in humans. They are most likely to occur in a surface water source. Giardi lamberia is the protozoan that causes "beaver fever".
	Nitrates Many surface water sources contain high concentrations of nitrates; however they may also occur in groundwater sources. Nitrates result from the seepage of water through soil containing nitrate-bearing minerals. Certain types of fertilizers also contain nitrates. Nitrates are also one of the by-products of decomposed animal and human wastes. The presence of nitrates in water can indicate possible pollution. In concentrations as low as 10 to 20 mg/L, nitrates can cause illness or even death in infants under six months of age. The nitrates affect the ability of their blood to carry oxygen. This oxygen starvation is commonly known as "blue baby" syndrome. The best method of treatment for nitrates is to determine the source and eliminate it. Water wells should be properly constructed in order to prevent contamination from surface run-off. Nitrates can be removed through deionization or reverse osmosis.