Experimental Study On In-situ Repairing Technology Of Polluted Source Water By Bio-Film Curtains

With development of social economy, industrial and agricultural productions have caused a certain degree of pollution to surface water environment. Particularly, the drinking source water pollution has been attracted public attention. On basis of related researches at home and abroad,we took activated carbon fibers as bio-film carrier, cultivated bio-film on the fibers through natural bio-film hanging to form bio-film curtains, and made a series of in-situ water quality restoration experiments with the curtains for polluted source water in order to find out a low-cost but high-efficient new technology of in-situ water quality restoration for polluted source water.Through experimental analysis, the following regulations and conclusions were obtained.(1) The restoration effect of polluted source by bio-film curtain technology was satisfactory. The mass concentrations of CODMn, NH3-N, TN and turbidity reduced from 9.62mg/L, 0.93 mg/L, 5.18 mg/L and 75 NTU to 3.5 mg/L, 0.28mg/L, 1.25 mg/L and 4 NTU, the maximum removal rate could reach 64.4%, 69.6%, 76% and 94.5%. The removal efficiency of TP wasn’t better, the mass concentration reduced from 0.25 mg/L to 0.19 mg/L with the removal rate of 22.9%;(2) The effect of water temperatures on water quality remediation of source water had a certain influence: the removal rate of CODMn and NH3-N was highest at 90% and 92% at the temperature of 25 ℃, whereas the highest removal rate of TP could reach 54% at temperature of 15 ℃;(3) The main effect of initial ammonia nitrogen concentrations on water quality remediation was: as the initial ammonia nitrogen concentration increased from 1.27 mg/L to 2.5mg/L, the removal rate of NH3-N reduced from 96% to 92%, the removal rate of TP reduced from 40% to 30%, the removal rate of CODMn basically stabilized at 85%;(4) The effect of water micro-circulation flow with dynamic auxiliary on the remediation of source water was obvious: the removal efficiency of CODMn and NH3-N were the best at the flow of 200 L/h with removal rate of 80% and 94.7%, but the removal rate of TP was38.5%.When the flow was 400 L/h, the removal efficiency of TP was best with the removal rate of 44.12%;(5) Through the orthogonal experiment, the best operating conditions of water quality remediation of source water by bio-film curtains were temperature of 25 ℃, initial ammonia nitrogen concentration of 1.5 mg/L, the micro-circulation flow of 400 L/h. The verification test showed that the average removal rate of CODMn, NH3-N and TP were 90%~94%, 90%~96%and 40%~50%.Our research results can be used as technical reference for the planning and design of polluted source water restoration.