生物炭对MSL污水处理及微生物群落结构的影响

Effects of biochar on sewage disposal and microbial community structure in multi-soil-layering system

为进一步提高多级土壤渗滤(MSL)系统对污染物的去除性能,通过对比不同形状土壤模块(方形结构和U形结构)的MSL系统,典型污染物去除率及微生物群落结构,探究生物炭对MSL系统污染物去除机理的影响.实验结果表明,在不同水力负荷下,生物炭可显著提高MSL系统对污染物的平均去除率(P<0.05),并表现出快速启动与抗冲击负荷能力,对COD_(Cr)、TP、NH_(3)-N、TN的平均去除率为87.74%、96.23%、97.65%、89.38%;U形结构可提高MSL系统对COD_(Cr)、TP、NH_(3)-N、TN的平均去除率,但与方形结构无显著性差异(P>0.05)(TP除外);生物炭提高了MSL系统中氨氧化细菌以及反硝化菌属的相对丰度,强化了系统对氨氮的去除;U形结构提高了亚硝酸盐氧化细菌的相对丰度,使脱氮过程更加顺利.因此,生物炭通过调节MSL系统的微生物群落结构特征、改善系统水分运动状态,增强了系统对典型污染物的去除能力与抗冲击负荷的能力.

To further improve the efficiency of multi-soil-layering(MSL)systems,the effects of biochar on the removal mechanism were investigated through the comparison of typical pollutant removal efficiencies and microbial community structure in MSLs with different shaped soil modules(square and U-shaped).The results showed that biochar could significantly improve the average removal rate of pollutants in MSLs(P<0.05)under different hydraulic loads,exhibiting fast start-up and shock load resistance.The average removal rates were 87.74%,96.23%,97.65%and 89.38%for COD_(Cr),TP,NH_(3)-N and TN.The U-shaped structure could improve the average removal rates of COD_(Cr),TP,NH_(3)-N,and TN,which was not significantly different from the square structure(P>0.05)(except TP).Biochar enhanced the removal of ammonia nitrogen by increasing the relative abundance of ammoniaoxidizing bacteria and denitrifying bacteria,and the denitrification became more smooth with a higher relative abundance of nitrite-oxidizing bacteria in U-shaped MSL system.Therefore,biochar enhanced the efficiencies and stability by regulating the structural characteristics of microbial communities and the waterflow in MSL systems.