Research On Biologically Enhanced Active Filter Of Remove Characteirstics Of Trace Pollutants In Water

In these days,conventional water purification process already can’t guarantee the quality ofdrinking water,with the deterioration of surface water quality and the improvement of drinkingwater quality standards.So the processing techniques of micro-polluted raw water need to beenhanced urgently.In this paper,artificially compound raw water that simulationed with traditionaltechnology precipitation of the water was treated as research object and performance of biologica-lly-enhanced active filter （BEAF） to the removing of pollutants was studied.During microbialinoculating and enrichment,the dynamic changes of the biomass along the layer and pollutantsremoval rate were determined; after a mature stability of biological membrane, biological activityalong the layer of BEAF was researched; active carbon adsorption and microbial degradationfunction and dsynergistic effect of both in BEAF were discussed.In the end,BEAF under lowtemperature in removal stability of NH₄⁺-N and recovery of the second device starting wereinvestigated.The main results are summarized:Filter applies dynamic culture biofilm forming mode. It takes60⁶5days to form biofilm inBEAF under the EBCT=15min condition. Comparison of the middle and later microbial biomasson filter material, biofilm has formed. Meanwhile, oxygen consumption rate is75%-85%andaverage removal rates of COD_Mn、NH₄⁺-N、NO₂^--N、chlorothalonil and chlorpyrifos are40%-50%,68%-75%,95%,90%and90%separately.In biological membrane mature stable period，average removal rates of COD_Mn、NH₄⁺-N、NO₂^--N、chlorothalonil and chlorpyrifos are50%、75%-78%、90%-95%、90%-92%and87%-90%.The results show that BEAF can keep higher removal efficiency.During low temperatur（e5℃b elow）,BEAF still has65%-68%removal rate of NH4+-N. BEAFcan returne to normal within3-5h when it closed1d,5d; after BEAF closed20d, it would returnwithin20h. It shows the advantage of BEAF inlow temperature operation and start againIn the BEAF,biomass and biological activity along the flow direction are reducegradually,but unit biomass activity of distribution is adverse.Among microbe,there is maineheterotroph about60%,next is nitrite bacteria and nitrifying bacteria is the least. COD_Mnremovalhas reached more than76.7%of the total rate in the upper35cm range of filter laye.Compared GAC with BAC the adsorption test shows that microbes can quickly releaseadsorption point to realize the regenerate active role and BAC can extend the service life of theactivated carbon. Contaminations removal are the result of active carbon adsorption and microbialdegradation in the biologically-enhanced active filter.