The concept,merits and domestic project examples of ecological disposal technique of dispersal sewage were introduced in detail.It was pointed out that the ecological disposal of dispersal sewage was investment-saved,energy consumption-reduced and ecological balance-protected advanced technology.This technology was suitable for small community,dispersal units and agencies,villages and other regions without pipe network pervaded and an available approach for solving present environment-protection problems and keeping sustainable development in China.
Substrate clogging is the worst operational problem for subsurface wastewater infiltration system （ SWIS ）, nevertheless quantitative understanding of the clogging process is currently very limited. In this study, the developing process of clogging caused by organic particle accumulation and biofilm growth was investigated in two groups of lab-scale SWIS, which were fed with glucose （dissolved organic matter） and starch （particulate organic matter） influent and filled with the same substrate made of 50% brown soil and cinder at a weight of 50%. Results showed that in glucose-fed systems the growth of biofilm in the substrate pores certainly caused remarkable reduction of effective porosity, especially for the high concentration organic wastewater, whereas its influence on infiltration rate was negligible. In comparison with biofllm growth, organic particles accumulation could rapidly reduce infiltration rate and the clogging occurred in the upper layer in starch-fed systems and the most important contribution of biofilm growth to clogging was accelerating the occurrence of clogging.
