| As the society attaching great importance to sewage treatment, the biological aerated filters(BAF) which has the unique advantages to meet the needs of the development of the sewage treatment.And this process is along physical entrapment with biological treatment in the same reactor, which has the advantages of little land occupation, low investment and good performance.We use the post-denitrification system and the pre-denitrification system to treat the domestic sewage of campus discharged from the process of bio-flocculation and adsorption.The BAF use ceramics grain as the biological filter material.And we target for the study of the removal efficiency of COD, ammonia nitrogen and TN,then discuss the removal mechanism.The process of bio-flocculation and adsorption use the synchronous training method to cultivate the sludge and make it domesticated, after a week,the concentrations of MLSS in the regeneration tank and flocculation pool are above 3500mg/L、1600mg/L respectively, the removal rate of COD is about 70%, all of those mean the activation of the biological flocculation adsorption process has finished. In the two-stage biological aerated filters process,the way of hanging membrane is sludge inoculation firstly and then continuous training by which we can research the biofilm culturing. In two weeks, the removal rate of COD and ammonia nitrogen in the 1#、2# filter candle all reach about 70%, at this time we think the biofilm culturing in two aeration biological filter is successful.In the stable running period of the bio-flocculation and adsorption process,the removal rate of COD, ammonia nitrogen,TN are 54.18%,18%,12%,the concentration of raw water are as follows:140mg/L, 15.5mg/L,20.35mg/L,and the effluent are respectively:70mg/L,13.13mg/L,17.5mg/L.It’s clear that the removal effect of biological flocculation and adsorption process to ammonia nitrogen and total nitrogen is poor, and need to increase the depth of the treatment plant.In the study of the treatment to the domestic sewage of campus discharged from the process of bio-flocculation and adsorption by the post-denitrification system,the 1# filter candle is aerobic filter,the 2# filter candle is anaerobic filter,during the incubation period of the post-denitrification filter candle, cultured continuously 15 days without adding carbon source,the average infuent COD concentration is 31.35mg/L,the effluent concentration is 27.3mg/L,the removal rate is just about 12%,but the influent ammonia nitrogen concentration is below 3mg/L,the effluent concentrate is obout 1.11mg/L,this result can not indicate obviously heterotrophic bacteria multiply.Adding carbon source to the reactor after operating 15 days,the influent COD concentration of the anaerobic filter is about 100 mg/L,the effluent concentration is below 40mg/L,the removal rate reaches 63%,the influent ammonia nitrogen concentration is about 0.57 mg/L,it indicates that heterotrophic bacteria used the organism to multiply after adding carbon source,denitrification filter candle completes the starting culture 7 days.In the stable running period of the post-denitrification process,the average influent concentration of COD, ammonia nitrogen, total nitrogen are 70mg/L,13.17mg/L,17.5mg/L,the effluent concentration of aerobic filter column are 29.27mg/L,1.43mg/L,15mg/L, the average removal rate can reach 58.77%,89.21%,11%; the effluent concentration of anaerobic filter column is 25mg/L,0.66mg/L,14.5mg/L,the removal rate of COD is only 12.63%. The removal rate of COD,ammonia nitrogen, total nitrogen in the whole system are 67.08%,95.13%,14%,The post-denitrification effect is not obvious.In the study of the treatment to the domestic sewage of campus discharged from the process of bio-flocculation and adsorption by the pre-denitrification system,1# filter candle is anaerobic filter,the 2# filter candle is aerobic filter,using culture quickly with adding carbon source during the incubation period of the post-denitrification filter candle, during the incubation period, the influent, average COD concentrations are 120 to 160mg/L, 143.8mg/L,respectively,after operating three days, the average effluent COD concentration is 67.5mg/L,the average removal rate is 53.08%, without circumfluence,the ammonia nitrogen removal rate approaches zero and it varies with time changes,the denitrification filter candle is cultured successfully only 7 days.In the stable running period of the pre-denitrification process,the average influent concentration of COD, ammonia nitrogen, total nitrogen are 110.8mg/L,22.42mg/L,28.55mg/L,the effluent concentration of anaerobic filter column are 40.55mg/L,10.32mg/L,11.29mg/L,the average removal rate can reach 59.82%,53.81%,60.04%;he effluent concentration of aerobic filter column are 18.2mg/L,1.05mg/L,9.49mg/L, the average removal rate can reach 54.88%,90.14%, 15.94%. The removal rate of COD 、ammonia nitrogen、total nitrogen in the whole system are 82.66%,95.14%,66.64%,The pre-denitrification have a good removal efficiency.Compared with the removal efficiency by the post-denitrification system,the pre-denitrification system can get better efficiency about advanced nitrogen removal. Figure[27] table[5] reference[62]... |
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