Study On Treatment Of Micro-polluted Source Water By Biological Aerated Filter

This research has conducted to evaluate the performance of zeolite biological aerated filter(ZBAF) removing organic matters,ammonia-nitrogen,turbidity and UV₂₅₄ in micro-polluted source water.Furthermore,several affecting factors of ZBAF process have been examined which are hydraulic load,hydraulic retention time(HRT),water temperature, the air/water ratio,backwash,impact load and shut down of BAF.Experimental results showed that treatment effect of micro-pollutants source water is excellent,the removal rate of COD_Mn,ammonia-nitrogen,UV₂₅₄,turbidity,dimethyl phthalate(DMP),diethyl phthalate (DEP),dibutyl phthalate(DBP) and di(2-ethylhexyl) phthalate(DEHP) can be reached 18.97～49.00%,83.67～98.84%,1.18～12.35%,82.08～97.52%,58.03～98.19%,19.28～92.75%,19.18～97.40%and 38.15～85.90%,respectively,under the conditions of hydraulic load of 5.0 m³/(m²Â·h),HRT of 40 min,air/water ratio of 1:1 and water temperature of 5～28℃.The increase of HRT and water temperature can improve the treatment effect of ZBAF. ZBAF has strong shock resistant capacity against ammonia-nitrogen and organic matters. Backwash has little impact on treatment effect of ZBAF.Shutdown of BAF has minor impact on removal effect of ZBAF,ZBAF can return to normal operation quickly after restart.The average removal rate of humic acid is 48.61%under the conditions of hydraulic load of 5.0 m³/(m²Â·h),HRT of 40 min,air/water ratio of 1:1 and water temperature of 22～28℃, as well as the influent humic acid concentration of 6.07～21.7mg/L.The biofilm on the media surface mainly presented in dispersive form.The biomass in the BAF decrease gradually from the bottom layer to the top layer along the water flow.More coccobacteria and bacillus were found in forepart of BAF,at the same time less bacillus and more filamentous bacteria were discovered in outlet of BAF.