| Water source of J city, which lies in the downstream of Taihu Lake, was effectedby the well-developed industry and agriculture inside the city and in the upperstream and couldn’t reach to the national standard of water quality for many years.In order to improve the quality of drinking water, ozone and biological activatedcarbon treatment process was used after traditional process to effectively removeorganic matters in the two major water plant, S water plant and G water plant in Jcity. Because of poor water quality, chlorine disinfection byproducts in tap water wasstill widely followed after ozone and biological activated carbon advanced treatmentand they deserved further research. Meanwhile, Owing to the poor quality of sourcewater, the municipal water supply pipe-work in S city has been extended from urbanto village since2004in order to ensure the drinking water safety in countryside. Theresearch aimed to change tendency which happened in pipeline of tap waterespecially disinfection byproducts was still blank and its couldn’t ensure if the qualityof tap water would be better or not.This research included two parts. The first part, investigated the water sourceand tap water quality of the two Water Plant in J city, explore the influence of boilingon tap water quality and the health risk caused by disinfection byproducts,investigation the difference of water quality and health risks between urban andrural after network been integrated. The second part, activated carbon had the bestadsorption effect was screened among four kinds by water test.Results showed that the concentration of organic matters and ammonianitrogen were high in the water source of S water plant.PAHs had been detected butlower than the limited value of national standard. Ammonia nitrogen could besignificantly removed and removal rate over71%; Part of PAHs could be removed, theremoval rate of the naphthalene is about36%after the wetland treatment.Treatment technology of S water plant had a good removal effect on CODMn,ammonia nitrogen, naphthalene, the removal rate were47.0%,76.1%and41.4%. For high value of CODMn (the concentration range is4.68～6.69mg/L), a large numberof disinfection byproducts were been generated, concentration of trihalomethanes intap water was49.20μg?L-1, halogen acid was9.34μg?L-1in August,2012. THMwere the main type of chlorine disinfection by-products, accounted for over84%ofthe two kinds. DCBM and DBCM were the major tape of THM and occupied over60.8%. Concentration of disinfection byproducts in G water plant were lower thanthat in S water plant, but still higher than other cities, THM were the main type too.Compared the water quality between villages and urban, the result showed that Nomatter in July or October, village sites demonstrated a concentration of THM highervalues than urban. Based on the health risk assessment model recommended by USEPA, the carcinogenic risk of drinking water in all of the urban and rural sites wasfound over the recommended acceptable level of1×10-6in both months. Thecarcinogen risk in village sites was far higher than that in urban sites, countrydrinking water safety problem requires sustained attention. Boiling could decreasedthe risk of drinking water under1×10-6because THMs could been removed over90%,but HAAs were largely increased especially of MCAA and TCAA, however, theincreasing part had a no singnificant influence on health.Water test started with4kinds of activated Carbon, the results showed that the Carbon A had betterchloroform removal ability than the other three kinds, removal rate was74%afterfiltrating250L. The TOC removal effect of4kinds of activated carbon were not ideal,after filtrating250L, removal rate of4kinds of activated carbon were all below15%,removal rate of carbon A just14.3%. |
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