有机负荷对潮汐流人工湿地净化农村生活污水的影响

摘要

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 or⁃ganic pollutants was the main factor limiting COD removal efficiency of the tidal flow;COD removal efficiency of the sys⁃tem may reach as high as 95�6%;the ammonia nitrogen ( NH4+⁃N) removal efficiency increased with rising organic pollu⁃tant loading rate from 85.2% to 98�7%;and higher organic pollutant loading favored assimilation of heterotrophic bacteria and enhanced denitrification. The removal of total nitrogen ( TN) followed a trend similar to that of NH4+⁃N with the high⁃est TN removal rate reaching up to 80.3%. Although adsorption was regarded as the primary pathway of phosphorus remov⁃al, which was determined by influent phosphorus concentration, the proportion of total phosphorus (TP) removal through adsorption was low due to the poor adsorption capacity of volcanics. Higher OLR stimulated phosphorus accumulating or⁃ganisms (PAOs) to absorb P, pushing TP removal rate up to 71�0%.%农村生活污水排量逐年增加，传统人工湿地复氧能力较差，床体氧环境直接影响污染物去除效果。通过模拟农村生活污水间歇排放特征，构建新型潮汐流人工湿地小试试验，对比研究了不同COD负荷下（167�9、221�9、610�3和760�0 g·m－2·d－1）床体氧环境和污染物去除效果。结果表明：有机物浓度是潮汐流COD去除效果的主要限制因素，COD去除率最高为95�6％；NH4＋⁃N去除效果随有机负荷增加而逐渐升高（85�2％～98�7％），有机负荷增加有助于加强异养菌同化作用。 TN去除规律同NH4＋⁃N，反硝化强度因有机物增加而增加，TN去除率最大为80�3％。火山岩吸附P性能较差，而有机负荷的增加促进了聚磷菌（ PAOs）的吸P作用，TP去除率最高达71�0％。