Constructed Wetland Treating Municipal Sewage Applications And Mechanistic Studies

Water pollution became more and more serious with rapid development of economy. Surface flow wetland was a new developing technology using soil-plant-microorganism system to treat wastewater as a little cost technology in both capital investment and operation and environment-friendly. As conventional Surface flow wetlands had much land areas requirement and took low loading and low purifying capability. In this paper, an improved Surface flow wetland was designed and the work was done as follow:1. An improved free water surface constructed wetland was improved as follow: Soil substrate was increased to 60cm deep. Influent flows in from the surface, effluent flows out from the bottom of this system. hydrophytes planted are typha orintalis and phragmites australis. The treatment efficiency of this free water constructed wetland to urban domestic sewage had been studied for six months, the removal rate was 87.6% for CODcr.2 . Microorganism is the main function on removal of organic contamination and nitrogen in constructed wetland, plant's root and its exudation improves the microorganism greatly. In the paper, microorganism's density, activity of typha orintalis and phragmites australis's rhizosphere were researched. The result showed that in typha latifolia and phragmites australis's rhizosphere, microorganism's density and activity were enhanced greatly. phragmites australis'rhizosphere was more suitable for nitrate bacteria than typha orintalis 's.