垂直流人工湿地填料的淤堵机理初探

应用人工湿地技术处理污水时,填料的淤堵往往是制约其处理功效和使用寿命的主要因素.本研究采用垂直流人工湿地单元模型,通过测定填料有效孔隙率与截留SS总量、COD降解量、生物膜的增长量之间的关系,初步探讨填料淤堵机理.结果表明:进水中悬浮颗粒全部为无机颗粒的系统较进水中全部为溶解态污染物质的系统更易造成淤堵,进水中全部为溶解态污染物的系统至实验结束时未出现淤堵现象.淤堵发生后,填料上层的渗透系数明显低于中下层,表明淤堵主要发生在填料上层部分;截留的不可生物降解无机SS、被截留但未被降解的有机SS、生物膜的生长及老化脱落、以及被上述物质吸附的水是导致淤堵的主要原因.淤堵发生后,湿地日污染物去除总量降低,湿地功效受到影响.

Primary study of clogging mechanisms of substrates in vertical flow constructed wetland

When constructed wetlands are applied in the sewage treatment,the clogging of substrates appears to be the primary limiting factor in its processing efficiency and the service life.In the present study,the clogging mech- anism was primarily discussed by analyzing the relationships between the available porosity rate and SS,COD and the biomembrane growth in the vertical flow constructed wetland(VCW)unit models.The results indicated that the inorganic SS resulted in the clogging of substrates easier than the organic SS to create.There was no clogging phenomena in the system with the soluble pollutants in influent.When the clogging was present,the penetration co- efficient in upper part became obviously smaller than that of the middle and lower part,indicating that the clogging mainly occured in the upper part.The main reasons for the clogging of substrates were the temporarily intercepted inorganic SS,which could not be biodegradated,the intercepted organic SS that hadn't been biodegradated in time,the growing and falling-off of biomembranes,as well as the water adsorbed by those above materials.The pol- lutants removal quantities per day reduced as the clogging appeared,and the wetland efficiency was affected.