| In recent years,the problem of water pollution has become more serious,it is difficult for the conventional drinking water treatment processes to meet more strict standards of drinking water quality.Single supplying source cannot meet the needs of the urban development.Enhanced conventional treatment process is the effective and economical ways accepted by water treatment plant to solve the problem of water pollution.Municipal waters were used in a certain city,as the contaminants are complex and greater diversity of multiple source water and the water plant process was need to all kinds of water quality,hunting for compatible with multiple source water enhanced conventional treatment process will become a very important field of water research.Give full consideration to the water area and representative of the sampling points,long-term sampling monitoring was conducted in a certain city,the pollution characteristics of water sources and the risk evaluation of HS,YC and XJ were investigated.The results showed that the water quality of HS and YC were in a stable state,and XJ water quality was bad.The three water sources were at seasonal taste and odor,algae and microcystin algae toxins(MCs)and trace organic pollution of water quality problems,and XJ at ammonia nitrogen and arsenic water quality problems.The seasonal taste and odor,and MCs concentrations during certain period of summer in the three water sources showed a significant correlation respectively with the water content of algae and cyanobacteria,and dimethyl isobenitol(MIB)and ?-ionone(BI)were the main cause of olfactory pollutants,higher than 10 ng/L and the concentration of MCs was in low level,less than 1?g/L.The ten OCPs,fourteen PAHs,six PAEs,seven BPs and nine antibiotics got higher detection rates with the concentrations at ng level.it was found that the spatial and temporal distribution characteristics of the five types of typical toxic pollutants varying,and the pollutant concentration distribution with trend of XJ>HS>YC.The concentration range of OCPs?PAHs?PAEs and BPs in XJ were 540.1~753.4 ng/L,100.6~357.1 ng/L,421~814 ng/L and 25.8~578.9 ng/L.As a whole,the pollution level in HS and YC was low,and XJ was low and mid.The pollutants exposure level is considered acceptable,which does not cause obvious risk of carcinogenic or non-cancer for human health,but the ecological potential risk of some single pollutant still need attention.The compatible with multiple source water of seasonal taste and odor,algae and MCs removal by enhanced conventional treatment process was established in a certain city.The results showed that removal of taste and odor and MCs by conventional water treatment process was reveal poor.Potassium permanganate composite ozone pre-oxidation can realize the complementary advantages of oxidant,improved taste and odor,algae and MCs removal efficiency.The removal efficiency of the 4 kinds of taste and odor such as GSM,MIB,BI and BC by ozone oxidation was better,the removal efficiency of GSM and MIB by potassium permanganate and sodium hypochlorite were limited.The removal efficiency of MCs(three isomers MC-LR,MC-YR and MC-RR)by ozone,potassium permanganate and sodium hypochlorite were good,and the algae and chlorophyll a has the certain removal effect.The water pollutants,taste and odor,algae and MCs were showed the trend of YC>HS>XJ,BI>BC>GSM>MIB,MC-RR>MC-YR> MC-LR.Ozone oxidation process for taste and odor and MCs and potassium permanganate oxidation process of MCs are consistent with the pseudo first order reaction kinetics,and the reaction rate constant showed the trend of BI>BC>GSM>MIB?MC-RR>MC-YR>MC-LR.Ozone oxidation process existed the direct response and the ·OH indirect response.The ozone oxidation of GSM and MIB mainly relied on the decomposition of ·OH,and the BC and BI existed direct oxidation of ozone oxidation,and the ·OH indirect response for the molecular structure of the carbonyl.The different pre-oxidation,powder activated carbon(PAC)adsorption and oxidation(adsorption)-coagulation enhanced conventional treatment to improve the trace organic pollutants removal were investigated.The results showed that the removal efficiency of trace organic pollutants by conventional water treatment process was limited,and pre-oxidation-adsorption-coagulation combination treatment process,especially the composite potassium permanganate and ozone oxidation-PAC-coagulation combination treatment process for trace organic pollutants removal effect is the best.The removal rate of OCPs??10PAHs??PAEs?BPs and antibiotic pollutants had reached 50%,85%,80%,90% and 92% by combination of composite pre-oxidation process.There was a strengthening removing role of trace organic pollutants by PAC under proper dosage(10~15 mg/L)with different degrees of trace organic pollutants removal.The enhanced conventional treatment process to removal ammonia nitrogen and arsenic pollution and improve the water quality of low temperature and low turbidity in XJ water source was proposed.Using different modified zeolite powder adsorption and modified filter material to enhance ammonia nitrogen removal.The method of combination of modified zeolite powder MZ was selects to enhance removal of ammonia nitrogen in water.And the best dosing method was at the beginning of the flocculation to eliminate the ammonia nitrogen.Compared with quartz sand,the modified zeolite particles MZK can significantly improve the removal efficiency of ammonia nitrogen and oxygen consumption in a longer experimental cycle.The adsorption characteristics of ammonia nitrogen by zeolite was analyzed,and the sorption process followed the pseudo-seconded-order kinetics equation,and the main mass transfer control steps are surface diffusion and particle internal diffusion,and more suitable for using Langmuir isothermal adsorption model,which was a process of spontaneous,exothermic and entropy reduction.Potassium permanganate pre-oxidation can transfer As(III)to As(V)which has strong affinity with coagulant hydrolysate,and reduction product Mn O2 adsorption,thus raising removal efficiency of arsenic,organic matter and turbidity.On the basis of research work,this paper presented the enhanced conventional treatment process technical plan for taste and odor,algae and MCs and trace organic pollution removal in the three water sources and ammonia nitrogen and arsenic removal in XJ.The study of compatible with multiple source water enhanced conventional treatment process in a certain city will provide data support and theoretical basis for its practical application in a certain waterworks,and it has very important practical significance to improve the certain local residents drinking water security. |
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