Industrialization and urbanization in the period is not yet well developed, very few natural water bodies polluted by human activities, large-scale drinking water treatment is the main target of sediment and colloidal material in water, and a small amount of pathogenic microorganisms. Source water through the conventional after processing can be transparent, colorless, odorless, taste delicious drinking water, drinking water treatment was the main task is to ensure the removal of turbidity and water-borne diseases from drinking those hazards. With the industry and urban development, and the extensive use of modern agricultural fertilizers and pesticides, more and more pollutants as industrial wastewater, sewage, municipal wastewater, agricultural runoff, atmospheric dust and precipitation, such as garbage permeate into the water, on water body into different degrees of pollution, water type and content of harmful substances more.
current problems facing drinking water treatment, in addition to the original sediment, colloidal substances and pathogenic microorganisms, the main are: organic pollutants, high ammonia, disinfection byproducts, water biological stability. Organic pollution is the contamination of source water the most important issue facing the drinking water treatment. human synthesis of organic compounds in a large part of the Council through the industrial wastewater and domestic sewage into water bodies : untreated wastewater also contains a lot of human excretion of organic pollutants; agricultural runoff containing fertilizers and pesticides; caused widespread concern in recent years, dioxin, endocrine disruptors (environmental hormones) and other pollutants may also present in drinking water. These synthetic and natural organic matter has many Toxicological effects on human health, some organisms (such as humic acid, fulvic acid, etc.) will be in the drinking water treatment process with the added disinfectant (eg chlorine) reacts with a The removal process very limited role, domestic and foreign research results and actual production results show that for the removal of sediment and colloidal substances developed coagulation, sedimentation, filtration and other conventional treatment processes to remove organic matter in water only 20 %, and particularly like the dissolved organic matter, except in a very small amount of organic matter will be attracted to the flowers and the filter surface, the conventional treatment process was virtually no removal. unpolluted water content of ammonia could have been very low, but in recent years because of contaminated water, surface water in many areas the concentration of ammonia in source water exceeded or often exceed drinking water quality requirements of ammonia water (less .5 m A pair). Many of our water off points are used chlorination for disinfection, for the high ammonia source water, chlorine disinfection in order to get a lot of freedom of adding chlorine to the chlorine to break down ammonia, so that the chlorination of water is greatly increased. high chlorine content is more increased the problem of disinfection byproducts produced.
biological stability of drinking water quality issues dealing with the 20th century's age of 09. Ideally drinking water should not contain organic matter, heterotrophic microorganisms therefore can not multiply in tap water. The traditional theory is that disinfection, disinfection of water has been maintained at a certain concentration of residual disinfectant conditions, microorganisms in water can no longer reproduce in order to ensure tap water distribution network in the biological stability of the system. But recent research that, if the water contains a certain amount of heterotrophic microorganisms that can be used as organic substrate, then this water for the biological instability of water, even in the water to maintain a certain concentration of residual disinfectant, there are still relatively high microbial re- reproductive risk. particularly for large urban water distribution network and high water tank, because of long residence time of water, the remaining disinfectant was the possibility of complete decomposition, poor biological stability of drinking water pipe network is more vulnerable or water tank then the problem of microbial reproduction.
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