Abstract: Natural wastewater treatment system exampled by land treatment system is based on the principles of recycling and reusing wastewater, harmonious with the environment, unified optimization, and differencing with the positions. Land wastewater treatment technology cannot only remove most of the pollutants in domestic wastewater, but also made it with high reusing rates. In order to promote the technical innovation of this kind of wastewater eco-treatment system and its wide application in China, and to provide a scientific and technical basis for the system implementation, a discussion was made on the subsurface wastewater infiltration system. Its process, characteristics, and principles were introduced, and the technical challenges in its application and corresponding solutions, including substrate choosing methods and the ways to relieve soil collision and enhance nitrogen removal were presented. The authors suggested that strengthened pretreatment should be emphasized, and the ways for raising hydraulic load should be adopted.

Key words: Di-n-butyl phthalate, Biodegradation, Mangrove