Experiments of nitrogen and phosphorus removal from rural domestic wastewater in the Taihu Lake basin were carried out by the two-stage subsurface flow constructed wetland process.

, so a small-scale subsurface-flow constructed wetland (SFCW) in the investigation was conducted to study the purification effect on swine wastewater.

The subsurface flow constructed wetland was covered with the harvested wetland vegetation for the sake of heat preservation.

In consideration of stormrunoff pollution problems existing in many wa tersheds in our country,we utilized subsurface flow constructed wetlands to research th e problems.

The nitrification ability of different layers in a subsurface constructed wetland treating sewage was measured .

Influence of ratio of carbon to nitrogen(C/N) and nitrogen source on denitrification effect in the subsurface constructed wetland were researched.

Base on the two stage subsurface constructed wetland system running at the suburb of Siping city in Jilin province,the applicability and characteristics of the two stage system which had especial active media and measurements of isolation for temperature protection were studied and the advantages of the two stage system in the pollution removal were analyzed.