两种生物电化学系统原位缓解人工湿地生物堵塞效果

生物电化学系统(Bio-electrochemical Systems, BES)利用附加电场或自产电场可以促进EPS分散、降解和利用, 可在一定程度上控制和缓解人工湿地的生物堵塞。为此, 研究采用CW-MEC和CW-MFC两种生物电化学系统对不同生物堵塞时期的人工湿地进行干预, 通过比较系统直观堵塞指标(孔隙率、出水速率)、净化效果(COD和氮的去除)及垂直方向上分层EPS的含量等来评价不同干预时机, 两种BES系统对生物堵塞的缓解能力。结果表明: 两种BES系统均能体现较好的堵塞缓解效果。堵塞前干预, CW-MFC系统能很好地维持污染物COD、TN去除效果(91.4%—61.3%和65%—40%)并提高出水速率(变化率为CW组67.6%); 堵塞后修复, CW-MEC系统能显著减少上层EPS含量, 恢复系统孔隙率, 具有更好的缓解堵塞效果。这两种BES系统原位缓解人工湿地生物堵塞方面皆有较好的应用潜力。

EXPLORING THE IN-SITE MITIGATION OF BIO-CLOGGING OF CONSTRUCTED WETLANDS BY TWO BIO-ELECTROCHEMICAL SYSTEMS

It is common and unavoidable that constructed wetland bio-clogging is caused by the massive secretion of Extracellular Polymeric Substances (EPS) of microorganisms. Bio-electrochemical Systems (BES) using additional electric fields or self-generated electric fields can promote the dispersion, degradation and utilization of EPS, and can control and alleviate the bio-clogging of constructed wetlands to a certain extent. Therefore, in this study, two bio-electrochemical systems, CW-MEC and CW-MFC, were used to intervene in constructed wetlands in different bio-clogging periods. Removals of COD and nitrogen and the content of stratified EPS in the vertical direction were used to evaluate the mitigation ability of the two BES systems to bio-clogging at different intervention timings. The results indicated that the two BES systems showed good clogging mitigation effect. Intervention before clogging, the CW-MFC system can well maintain the removal effect of pollutants COD and TN (91.4%—61.3% and 65%—40%) and increase the water output rate (the change rate is 67.6% in the CW group). The CW-MEC system can significantly reduce the EPS content of the upper layer, restore the porosity of the system, and have a better effect of relieving clogging. Both of these two BES have good in situ application potential in alleviating bio-clogging in constructed wetlands, which provides reference for the effective prevention and control of bio-clogging in constructed wetlands during different periods.