不同种植季三塘生态治理工程处理农田退水效能分析

基于生态拦截渠耦合三塘生态治理工程开展农田退水污染治理研究,重点考察不同种植季(水稻种植季、小麦种植季)的农田退水水质变化情况,通过对比化学需氧量(Chemical Oxygen Demand,COD)和总磷(Total Phosphorus,TP)、氨氮(NH3-N)等污染物迁移转化规律及去除特性,揭示影响生态治理工程出水水质的相关因素。研究结果表明:三塘生态治理工程水稻种植季的总体治理效果优于小麦种植季,其中水稻种植季农田退水COD、TP、NH3-N平均去除率为34.6%、46.1%、58.9%,小麦种植季农田退水COD、TP、NH3-N平均去除率为40.4%、42.6%、54.8%;水稻种植季三塘生态治理工程处理后出水水质接近Ⅳ类标准,主要超标因子为COD,而小麦种植季出水水质为V类或劣V类,主要超标因子为NH3-N。

Study on the Effects of Nitrogen and Phosphorus Absorptionby Ecological Ditches

By using the simulated ditch experiment,the differences of nitrogen and phosphorus absorption capacities of 9 aquatic plants were studied,and the better varieties of nitrogen and phosphorus absorption capacity were selected to construct the ecological ditch and oxidation pond to study the nitrogen and phosphorus absorption effect.The results showed that the nitrogen and phosphorus residues in the simulated ditch water were signi ficantly reduced after planting aquatic plants.The biomass of Canna glauca,Myriophyllum elatinoides,Sorbaria sorbifolia,Pontederia cordata and Zizania was high,and the uptakes of nitrogen and phosphorus were high.Among them,the effect of planting Canna glauca and Myriophyllum elatinoides was the best.The concentration of nitrogen and phosphorus in farmland drainage decreased signi ficantly after being absorbed by aquatic plants in ecological ditches;the concentration of total nitrogen,soluble nitrogen and total phosphorus in main ditches decreased by 39.6%,40.1% and 36.9% respectively on average;the concentration of total nitrogen,soluble nitrogen and total phosphorus in branch ditches decreased by 6.6%,10.3% and 13.6% on average.The concentration of total nitrogen and total phosphorus in the oxidation pond could be further reduced by 17.7%and 13.3%.Ecological ditches can effectively intercept nitrogen and phosphorus in water,and have good ecological benefits of purifying water to obtain improved water quality.