| Combined improved filtering technology by using self-made Iron Oxide Modified Sands(Short forIOCS),and biological treatment technologyon treatment to micropolluted water which containe NH3-N and UV254.Compound biofilm properties on the surface of IOCS is discussed,test of start performanceis conducted,and variationof pH and DO is carried out,then the distributed of biophase and biomass and the media surface morphology are analysised,comparison of effect to NH3-N and UV254is done beween Bio-RQS and Bio-IOCS.The results showthat,The surface of IOCS can be successfully covered with microorganisms by compound biofilm formation techno logy,and shortenthe time of biofilm,the compound biofilm process is about8d;Concentration of pH and DO decreased and effluent ammonia less than0.5mg/L can be used as conditions to judge the successful of biofilm;Removal rate to ammonia nitrogen of Bio-IOCS increases fast, rising from about2%to85%,and the average removal rate to UV254is42%; After the success of biofilm, biofilm is the main zoogloea, filter column biological is variety, good removal effect to micropollutants,and biomass on Bio-IOCS is higher44nmolP/g filters than that of Bio-RQS, and biomass mainly concentrated on the surface about20cm thickness of the filter.At the stable stage,the average consumption of DO is1.8mg/L,higher1.3mg/L than that of Bio-RQS;Removal effect of Bio-IOCS to NH3-N is greatand stability,average removal efficiency is86%.good removal effect to UV254,and the average removal rate is57%;The surface morphological characteristics of IOCS has more rough and porous structure, specific surface area significantly increases and microorganisms tightly attached to the surface. The attached biofilm makes the roughness and porosity on the surface of filter media increasing further, thus, it has stronger physical adsorption abilities and biodegradation and bio-oxidation capacities,then good removale effect to NH3-N and UV254.At the stable stage,backwashing is studied on Bio-IOCS,backwashing operation mode is determined by orthogonal test,and the effect of water and recovery of backwash under the optimum parameters is discussed.The results show that,the way of backwashing combination water with gas is suitable to Bio-IOCS,and the optimal parameters is:qg=8L/(s·m2),tj=6min; qgo=8L/(s·m2),qw0=5L/(s·m2),t2=6min;qw=10L/(s·m2),t3=4min;The overall effect can be restored to normal in about1h after backwashing;recovery time to turbidity and ammonia nitrogenis25min and40min approximately.The removal effect to ammonia nitrogen in different filterspeed and under the different concentrations of ammonia nitrogen byBio-RQS and Bio-IOCS pilot tests in Foshan water group Shakou water works.and the removal effect ofNH3-N and UV254are studied. The results are shown as follows:(1)At the bio formation stage,the removal rate to NH3-N is from44%up to77%,and the average removal rate to UV254is42.28%;(2)At the stable stage,removal effect of B-IOCS to NH3-N and UV254is stable,the average removal rate to NH3-N and UV2.54is about80%and46.09%;(3)The removal efficiency of ammonia nitrogen on different velocity to Bio-IOCS is75.2%,95.2%,86.3%, is approximately11.7%,7%,2.1%higher than that of Bio-RQS in the same velocity. In the condition of filtering speed4m/h,the removal efficiency of ammonia nitrogen to Bio-IOCS is higher than that of Bio-RQS under the same influent ammonia concentration levels;(4)In the same influent,the average removal rate of B-IOCS to UV254is46.15%,the removal rate is range from40%to55%,the range of fluctuation is little, removal effect is stable,andthe removal rate is higher about25%than that of Bio-RQS. |
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