Study On Treatment Of Pollutants By Combined Process

In recent years,the surface water of China has been polluted generally.Using the conventional water treatment process to deal with the micro-polluted water can not meet the strict drinking water standards.Thus,finding the efficient,economical and applicable water treatment process to ensure the safety of drinking water is hotspot all the time.The dissertation takes the micro-polluted river network water of a region as research object.Effect of combined process with biological treatment technology,PAC and UF on pollutants of micro-polluted water and influence factors of membrane fouling were investigated.The optimum amounts and adsorption saturation time of PAC were determined by jar test.Then,the amounts of PAC was further optimized in pilot based on the biological technology.The removal efficiency of the process in different hydraulic retention time and different biological operation environment were investigated,As well as the influence of operation parameters of UF on membrane fouling,and determining the optimal conditions of combined process.Finally,the removal efficiency of pollutants in combined process were investigated in optimal conditions.The results showed:(1)The adsorption saturation time of PAC was about 80min,the optimal amounts was 140mg/L in jar test.In pilot,the optimal amounts of PAC was determined by combined was 50mg/L and the hydraulic retention time of the biological tanks was 84min.The optimal conditions:raw water ?No.1 biological reaction tank(not aeration)?No.2 biological reaction tank(aeration)?ultrafiltration membrane ?effluent water.(2)In order to prevent the membrane fouling,the optimal parameters of the ultrafiltration membrane were determined by orthogonal test:membrane flux 25L/(m2·h);water production 30min;combined water and air backwashing 70s;hydraulic cleaning 40s;after six physical cleaning cycles,it was used 100mg/L sodium hypochlorite for chemical cleaning.cross-flow with 0.3m3/h.(3)The average removal rate of ammonia nitrogen?UV254 and permanganate consumption(CODMn)were 94.8%,85.2%and 62.8%,respectively,when ammonia nitrogen,UV254 and CODMn of raw water were 2.48 to 3.05mg/L,4.64 to 5.12mg/L and 0.284cm-1 to 0.336 cm-1,and effluent water were 0.09 to 0.21mg/L,0.042cm-1 to 0.050 cm-1,1.72 to 1.96mg/L.At the same time,the effluent turbidity was below 0.1 NTU,and particulate matter was removed effectively.The average removal rate of DOC was 43.8%.Moreover,there was no accumulation of nitrite nitrogen in the reactor.The effluent ammonia nitrogen,CODMn,turbidity,nitrite nitrogen could reach evaluation standard of the Urban Water Supply Modernized Waterworks in Zhejiang Province 2013.