Study On Treatment Of Micro-polluted Source Water By Activated Zeolite Biological Aerated Filtee

At present,the raw water pollution is serious increasingly,and special attention has been paid to the organic,nitrogen,algae and microcystin pollution.In this study,a biological aerated filter stuffed with activated zeolite was used for research on the starting and running performance,the process characteristic at low temperature,the removal effect of algae and microcystins under normal temperature from micro-polluted raw water in Hangzhou.Compared with the natural zeolite,activated zeolite was found to be suitable stuffing to fill biological aerated filter due to its inner microproe structure,larger speific surface aera and higher dynamic performance.Owing to the activated zeolite adsorption property,AZBAF could start up quickly through the natural hang film,and the nitrobacterium and nitrosobacteria could tend to mature in 23 days.Under low temperature,CODMn removal was influenced much by the variation of hydraulic loading,but air-water ratio increase dose little affection on the CODMn removal.The well ion exchange capacity and the surface characteristics of activated zeolite media keep a well ammonium adsorption and nitrification in the low temperature,the variation of hydraulic loading and air-water ratio was no effect on NH3-N removal.Under the optimum conditions of hydraulic loading 0.8 m3/m2·h)and air-water ratio 1:1,the average removal efficiencies of CODMn,NH3-N and alga were around 47.1%?91.9%and 42.4%,respectively.In the ZABAF,the biomass and biological activity at low temperature is lower than at normal temperature obviously,but the sufficient biomass and some cold-adapted microorganism keep the AZBAF presented a good removal effectiveness.After the backwashing operation,biomass was decreased in the AZBAF whereas an increase was found in the biological activity,and the biofilter could recover to the original level in 3 hours.The results showed that,the TMC concentration fluctuated from 0.39 to 0.97ug/L,and EMC/TMC was ranged from 0.077-0.185.Under the conditions of filteration rate at 0.8m/h and air-water ratio at 1:1,the average removal efficiencies of Chl-a,TMC-RR,TMC-LR,EMC-RR,EMC-LR were 74.4%,51.6%,58.8%,53.5%,62.1%,respectively.HRT had a obvious effect on Chl-a removal,and the organic in the influent could enhance the removal of MC whereas Chl-a had little effect on MC removal.