| With the growth of population and the increasing demand for water quality,the contradiction between water supply and demand of high quality drinking water is becoming more and more prominent.The surface water resources are easily affected by the natural environment and human factors,so it is very important to carry out the safety evaluation of drinking water source and study on the optimization of drinking water treatment process for ensuring the security of water supply when the surface water is used as the drinking water source.Huzhou is the typical area in which the high quality water sources are insufficient and several types of surface water source coexist.Through three types of surface drinking water source including river,reservoir and lake in Huzhou,water quality characteristics and treatment processes were analysed.According to monitoring data of different drinking water sources,nine regular water quality indexes were chosen as the emphasis for analysis of drinking water quality.Based on three types of drinking water sources,the results showed that the water quality decreased in order of reservoir,lake and river and separately conformed to Class ?,Class ? and Class ?.The water quality of reservoir was relatively stable,just total nitrogen level was still out of the standard limit.The water quality of Tai Lake fluctuated with the seasonal and annual variation,and the majoy contaminants were total iron,total nitrogen and total phosphorus.The water quality of river became better year by year,while total iron,total manganese and total nitrogen were out of limits severely.It was worth being concerned about the seasonal risks in river and Tai Lake while the concentration of some contaminants increased in winter and spring.The correlation analysis of nine water quality indexes was finished by the method of linear linear regression.It was found that the turbidity had the good correlation with other indexes.The distributing situation of organochlorine pesticides,organophosphorus pesticides,phthalic acid esters in the drinking water sources of Huzhou were analysed.The results showed that the concentration ranges of these three micro-organic pollutants respectively were 2.0?269.1g/L,ND?202.5ng/L and 163.4?1966.5ng/L.They changed with the monthly variation as the same rule that the concentration declined from January to May,and rised from July to November.High detection rate of phthalic acid ester included dimethyl phthalate,dibutyl phthalate and di(2-ethylhexyl)phthalate,etc.High detection rate of organochlorine pesticides included dieldrin,aldrin and DDT,etc.Through organophosphorus pesticides,just dichlorvos and dimethoate were checked out.By comparison among three types of drinking water sources,the concentration of organochlorine pesticides in lake was least than that in reservoirs and rivers while the the concentration of organophosphorus pesticides in rivers was highest than that in reservoirs and lake.The concentration of phthalic acid esters almost did not have an impact by the types of drinking water sources.Through the water quality analysis between the inflow and outflow,the removal rate of organochlorine pesticides was higher than the removal rate of phthalic acid esters which was treated by conventional water treatment technology.The removal efficiency of water treatment process units and combinations was tested by the pilot-plant in Huzhou.The results showed that among all water treatment process units,the coagulation and sedimentation had the best effect on improving the six conventional water quality indicators except ammonia nitrogen and removing the characteristics organic pollutants,and the sand filter came second.Among the all water treatment process combinations,the removal efficiency of conventional treatment combined with advanced treatment process was best of all.It could improve the removal efficiency of permanganate index and phthalic acid esters to 74.0%and 71.8%.Potassium permanganate peroxidation with conventional treatment process as a pre-treatment technology had a best effect on removing permanganate index and phthalic acid esters with the removal rate of 45.5%and 52.1%than the pre-ozone and floating pool.The type of drinking water sources had an effect on the removal rate of water treatment. |
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