Zhao Lianfang, Zhu Wei, Tong Wei
College of Environmental Science and Engineering, Hohai University, Nanjing 210098, China.
J Environ Sci (China). 2009;21(6):750-7. doi: 10.1016/s1001-0742(08)62336-0.
The accumulation of organic matter in substratum pores is regarded as an important factor causing clogging separately in the subsurface flow constructed wetlands. In this study, the developing process of clogging caused by biofilm growth or organic particle accumulation instead of total organic matter accumulation was investigated in two grdups of lab-scale vertical flow constructed wetlands (VFCWs), which were fed with glucose (dissolved organic matter) and starch (particulate organic matter) influent. Results showed that the growth of biofilms within the substratum pores certainly caused remarkable reduction of effective porosity, especially for the strong organic wastewater, whereas its influence on infiltration rate was negligible. It was implied that the most important contribution of biofilm growth to clogging was accelerating the occurrence of clogging. In comparison with biofilm growth, particles accumulation within pores could rapidly reduce infiltration rate besides effective porosity and the clogging occurred in the upper 0-15 cm layer. With approximately equal amount of accumulated organic matter, the effective porosity of the clogged layer in starch-fed systems was far less than that of glucose-fed systems, which indicated that composition and accumulation mode in addition to the amount of the accumulated organic matter played an important role in causing clogging.
基质孔隙中有机物的积累被视为造成潜流人工湿地堵塞的一个重要因素。在本研究中，在两组实验室规模的垂直流人工湿地（VFCW）中研究了由生物膜生长或有机颗粒积累而非总有机物积累引起的堵塞发展过程，这两组湿地分别投加葡萄糖（溶解性有机物）和淀粉（颗粒性有机物）进水。结果表明，基质孔隙内生物膜的生长确实导致有效孔隙度显著降低，尤其是对于强有机废水，而其对渗透速率的影响可忽略不计。这意味着生物膜生长对堵塞的最重要贡献是加速堵塞的发生。与生物膜生长相比，孔隙内颗粒积累除了能迅速降低有效孔隙度外，还能迅速降低渗透速率，且堵塞发生在0 - 15厘米的上层。在积累的有机物量大致相等的情况下，投加淀粉系统中堵塞层的有效孔隙度远低于投加葡萄糖的系统，这表明除了积累的有机物量外，其组成和积累方式在造成堵塞方面也起着重要作用。
