生物碳含量对底泥活化原位脱氮及微生物活性的影响

Influence of biochar content on in-situ denitrification of sediment and microbial activity

以生物碳组合填料为载体,考察了不同比例生物碳对关镇河底泥活化原位脱氮系统构建时间、脱氮效果的影响,同时研究了不同比例生物碳填料成熟生物膜上生物量、微生物活性、硝化菌和反硝化菌数量。结果显示,组合填料中添加生物碳含量为5%、10%、15%时,脱氮系统的总氮(TN)去除率在处理第7 d、6 d和5 d时均达到80%以上,且运行稳定后其TN平均去除率分别为88%、90%和83%。生物膜上生物量随生物碳含量增加而增加,当生物碳含量为10%时,生物膜上硝化细菌、反硝化细菌数量最大,分别为1 g 6.7×104MPN和8.6×105MPN,脱氢酶活性为54.2μg/nmol,而生物碳含量为15%时,硝化细菌、反硝化细菌数量、脱氢酶活性分别为1 g 1.9×104MPN、1 g 1.7×105MPN和19.8μg/nmol,表明过高的生物碳含量不利于提高生物膜原位脱氮系统的脱氮效能及微生物活性。

To study the effect of biochar on the building time and efficiency of river sediment denitrification,a laboratory scale reactor was established,and the biomass,microbial activity,nitrobacteria and denitrifying bacteria counts of biofilm were investigated. In the biofilm reactor added with 5%,10% and 15% biochar,the removal efficiencies of total nitrogen（ TN） at days 7,6 and 5 were over 80%. In the steady running stage,the removal efficiencies of TN reached 88%,90% and 83%,respectively. Biomass was increased with the content of biochar in the combined packing. When the content of biochar was 10%,nitrobacteria,denitrifying bacteria and TTC-dehydrogenase activity were 6.7× 104 MPN per gram,8.6×105MPN per gram and 54. 2 μg / nmol,respectively. When the content of biochar was 15%,nitrobacteria,denitrifying bacteria and TTC-dehydrogenase activity were 1.9× 104 MPN per gram,1.7× 105 MPN per gram and 19. 8 μg / nmol,respectively,indicating that excessive biochar are not conducive to the efficiency of denitrification and microbial activity.