Study On Choice Of Pretreatment Techniques And Pipe-materials Of Direct Drinking-water

Presently, It is not safe to have the tap-water directly drinking because of resource pollution and chlorate disinfection and twice pollution of pipes. According to the actual situation of China, Pipe Direct Drinking-water is suitable to provide healthy and high-quality drinking-water.The study focuses on the pipe direct drinking water techniques of the tap-water in one city in North China. On the base of the former study of my colleagues, different technique combinations are compared about the treatment effection. And some related technique parameters were optimized. Furthermore the treatment technique effections of different direct drinking-water were discussed.From the study, ozone dosage was established to be added 0.8mg/L in ozone /activated carbon (O3/AC) techniques, additionally, this study compared the rates of removal of micro-organic contamination and disinfection by-products of water treated by four techniques of activated carbon (AC),ozone / activated carbon (O3/AC),ultraviolet/activated carbon (UV/AC),ozone /ultraviolet /activated carbon (O3/UV/AC)in pretreatment. The results showed that the rates of removal of TOC(total organic carbon) were 38.14%,44.85%,39.31%,39.74%; the removal rate of UV254 (ultraviolet absorbance at 254nm ) were 23.96%,70.26%,70.57%,72.53%;the removal rate of CHCl3 were 41.37%,42.79%,42.11%,45.11%; the removal efficiency of formation potentials CHClBr2 can reach to 100%, the removal efficiency of formation potentials CHCl3 were 35.44%,81.90%,64.58%,48.57%,the removal efficiency of formation potentials CHCl2Br were 50.46%,63.48%,71.89%,52.44%,the removal efficiency of formation potentials CHBr3 were 8.60%,27.82%,63.30%,11.32%。Two techniques, UV/AC and O3 /AC, were preferred. And some experiments were made about genotoxicity and biostability. The result shows that the values of tap water AOC are more than 100, which means it is not stable. While after the treatment of the two techniques, AOC values of tap water is about 50, which means better stability. The umu experiments show that the genotoxicity of tap water is higher. So the combination techniques of O3/AC and UV/AC can improve the security of drinking water. The influence of three kinds of pipes, i.e., stainless steel, copper and polypropylene (PPR) pipes, to water quality of high quality drinking water were investigated by monitoring variations of parameters like total organic carbon (TOC), turbidity, total bacterial number and dissolved metals in pipe soaking experiment. Comprehensively, stainless steel pipe was suggested to be supply the high quality water.These results have great significance to improve the current technique of dual water supply and promote the development this field.