城市污水的微生物-植物联合修复对水体N_2O、N_2和O_2释放的影响

Effect of Microorganism-plant Joint Remediation on N_2O,N_2 and O_2 Release Flux from Polluted Waters in Urban River

针对城市河道污染水体治理这一问题,采用自主研发的自然水体原位收集装置对微生物和微生物-植物联合修复过程中气体N_2O、N_2及O2释放的特征进行野外原位监测。结果表明:微生物菌剂和微生物-植物联合净化期间水体氧化亚氮(N_2O)释放速率均值分别为10.68、5.91μmol·m^(-2)·h^(-1),与对照比,降幅分别为16.37%和53.86%;氮气(N_2)释放速率均值分别为1.49、0.87 mmol·m^(-2)·h^(-1),降幅分别为5.70%和67.54%;氧气(O_2)释放速率均值分别为1.14、0.69 mmol·m^(-2)·h^(-1),降幅分别为14.93%和72.06%;微生物菌剂及微生物-植物联合净化期间,目测水体透明度转好,藻类含量降低,水体溶氧由超饱和状态(17.17 mg·L^(-1))降至正常水体溶氧水平(9.49 mg·L^(-1)),降幅达到50%,可能是水体氧气释放速率降低的原因。因此,微生物-植物联合净化能显著降低水体N_2O、N_2及O_2的释放速率,推测是由于微生物和水生植物对水体养分的同化作用产生营养竞争,抑制了微生物反硝化作用产生N_2O、N_2并抑制藻类生长产生O_2及增加水体溶氧的原因。

Considering the remediation of polluted water in urban area, this study investigated the effect of microbial agent（MAP ） and aquatic plant combined purification method（MAAPP） on N2O, N2 and O2 releasing characteristics from the water system, using a gas trapping device. The results showed the average N2O releasing flux during MAP and MAAPP period was 10.68 μmol·m^-2·h^-1 and 5.91 μmol·m^-2·h^-1, respectively, and decreased by 16.37% and 53.86% in contrast to the eontrol pond. The average N2 releasing flux during the MAP and MAAPP period was 1.49 mmol ·m^-2·h^-1 and 0.87 mmol ·m^-2·h^-1, and decreased by 5.70% and 67.54% in contrast to the control pond, respeetively. The average O2 releasing flux during MAP and MAAPP period was 1.14 mmol·m^-2·h^-1 and 0.69 mmol·m^-2·h^-1 and decreased by 14.93% and 72.06% in contrast to the control pond, respectively. During MAP and MAAPP period, water transparency was improved and over-saturation dissolved oxygen（ 17.17 mg· L^-1） was significantly reduced to nearly normal level（9.49 mg·L^-1 ）, with 50% decreasing rate. The results indicated that both MAP and MAAPP method eould reduce N2O, N2 and O2 releasing flux from water system. The mierobial agent and aquatic plant absorbed the water nutrients and competed with denitrifying bacteria and phytoplankton, inhibited of N2O, N2 and O2 producing and releasing from the polluted water.