Some County In Jiangxi Slightly Polluted Source Water Strengthening Treatment Technology

With aggravation of surface water contamination and the increased stringency of drinking water regulations presented, traditional water treatment processes in the waterworks can not guarantee the safety of drinking water. The micro-polluted source water in Gannan has its own nature characteristics, the focus of this thesis was to find an economic reasonable and operation convenient water treatment processes around the characteristics and actual situation of the county water plant.The reservoir source water of a county in Gannan was used as a model sample in this study, the effect of pollution indicators removal in water by enhanced coagulation and pretreatment processes were investigated. The hydraulic conditions of enhanced coagulation, selection of coagulation agents, potassium permanganate pre-oxidation, permanganate composite chemical pre-oxidation and powdered activated carbon pre-adsorption were investigated, the removal mechanism of those processes were studied. Through experiments, the results were attained as follows:(1) Under the conditions that260r/min of mixing stir intensity,2min of mixing stir time,80r/min of flocculating stir intensity,25min of flocculating stir time, turbidity of the treated water was0.88NTU, with the removal rate of98.63%, and the removal rate of CODMn was49.83%;(2) The optimum conditions of Poly Aluminium Chloride were10mg/L dosage, source water pH values. Under those conditions the removal rate of turbidity, CODMn, UV254, ammonia, iron, manganese were98.87%,60.70%66.21%,40.10%,95.10%,35.89%, and the pH of treated water was reduced0.16-0.53; The optimum conditions of Aluminum Sulfate were14mg/L dosage, source water pH values. Under those conditions the removal rate of turbidity, CODMn, UV254, ammonia, iron, manganese were98.85%,60.20%,65.31%,41.92%,95.40%,36.28%, and the pH of treated water was reduced0.28-0.53;(3) The optimum conditions of potassium permanganate were2min pre-oxidation,1.0mg/L dosage, source water pH values. Under those conditions the removal rate of turbidity, CODMn, UV254, ammonia, iron, manganese were99.09%68.78%,50%,44.19%,93.06%,91.04%;(4) The optimum conditions of permanganate composite chemical were2min pre-oxidation,1.8mg/L dosage, source water pH values. Under those conditions the removal rate of turbidity, CODMn,UV254, ammonia, iron, manganese were99.36%、57.84%、31.03%、40.32%、92.91%、72.55%;(5) The optimum conditions of powdered activated carbon were5min pre-adsorption,25mg/L dosage, source water pH values. Under those conditions the removal rate of turbidity, CODMn, UV254, ammonia, iron, manganese were98.90%,68.44%,75.00%,40.85%,96.88%,37.78%;The main conclusions of this paper were attained as follows:(1) Potassium permanganate pre-oxidation were better than permanganate composite chemical pre-oxidation and powdered activated carbon pre-adsorption in terms of removal of pollutants effects, dosage, and operating conditions, so potassium permanganate was chosen as the pretreatment agentia for the waterworks;(2) New process of water plant was determined through experimental study:Potassium permanganate oxidation-Grid flocculation tank-Precipitation tank with tilted pipes-Siphon filter-Clean water reservior-Secondary pumping station-Water supply network of county. Potassium permanganate were2min pre-oxidation,1.Omg/L dosage; The designing G of grid flocculation tank was60s-1, and GT was66546; Poly Aluminium Chloride was chosen as coagulant to the water plant.(3) In this study, current process of the water works has been analyzed. Potassium permanganate pre-oxidation was an economical and efficient water treatment compaerd with the existing pre-chlorination, it was suitable for the treatment of micro-polluted source water in Gannan.