Abstract: With increasing discharge of domestic sewage in the rural areas, conventional constructed wetlands gradually fail in reoxygenation capacity, oxygen environments of their beds directly affect pollutants removal efficiency. By simulating the characteristic of intermittent discharge of domestic sewage in the rural areas, a new type of artificial tidal flow wetland (ATFW) was constructed in lab for an experiment to explore impact of COD loading (167.9, 221.9, 610.3 and 760.0 g·m^-2·d^-1) on oxygen environment of the bed and pollution removal efficiency.Results show that concentration of organic pollutants is the main factor limiting COD removal efficiency of the tidal flow; COD removal efficiency of the system may reach as high as 95.6%; theammonia nitrogen (NH₄⁺-N) removal efficiency increased with rising organic pollutant loading from 85.2% to 98.7%; and higher organic pollutant loading favored assimilation of heterotrophic bacteria and enhanceddenitrification. The removal of total nitrogen (TN) follows a trend similar to that of NH₄⁺-N with the highest TN removal rate reaching up to 80.3%. Although adsorption is regarded as the primary pathway of phosphorus removal, which is determined by influent phosphorus concentration, the proportion of total phosphorus (TP) removal throughadsorption was low due to the poor adsorption capacity of volcanics. Higher OLR stimulated phosphorus accumulating organisms (PAOs) to absorb P, pushing TP removal rate up to 71.0%.  

Key words: tidal flow, rural domestic sewage, organic loading rate, DO condition