龙河人工湿地在北方冬季低温条件下的运行效率

OPERATION PERFORMANCE OF LONGHE CONSTRUCTED WETLAND UNDER LOW TEMPERATURE IN WINTER IN NORTHERN CHINA

人工湿地有着建设及运营成本低、水质净化效果好等显著优点,在河道水质净化等领域受到广泛应用。但是由于冬季低温条件下运行效果不佳,制约了人工湿地在北方的推广应用。通过构建“物化预处理(高效沉淀池)+人工湿地(潜流湿地+表流湿地)”工艺模式的多级复合人工湿地(3万t/d),探究冬季低温条件下人工湿地结合冰封保温措施对龙河水质净化的效果。分析了2019年12月至次年1月龙河人工湿地系统的运行效率,结果表明:该湿地系统对COD、NH_(4)^(+)-N、TP、SS去除率分别达到49.06%、77.72%、57.95%、38.73%,其净化能力在冬季仍然较高。对于不同植物组合的潜流湿地而言,香蒲-芦苇两级潜流湿地对NH_(4)^(+)-N、TP、SS的去除效果优于芦苇-香蒲两级潜流湿地,分别提高3.2%、11.1%和6.7%;但是二者对COD去除率无显著差异,说明不同植物组合对污染物的去除各有优势。综合而言,龙河多级复合人工湿地对污染物有较佳的去除效果,提高了人工湿地在冬季低温条件下的运行效率,为人工湿地在北方地区的推广应用提供了一定的借鉴价值。

Constructed wetland has been widely used in river water purification due to its lower construction and operation cost, at the same time it has a good water quality purification effect. However, the application of constructed wetland in north China is restricted for the poor operation effect under low temperature in winter. In this paper, a multi-stage composite constructed wetland project(30000 t/d) using the process combination of physicochemical pretreatment(high efficiency sedimentation tank)+constructed wetland subsurface flow wetland+surface flow wetland was explored, and the effect of ice insulation measures on the water purification of Longhe River under low temperature in winter was studied. The operating efficiency of the constructed wetland system from December to January was analyzed. Through the study and analysis of the operation efficiency, the results showed that the Longhe constructed wetland system has high removal efficiency of COD, NH_(4)^(+)-N, TP and SS, which was 49.06%, 77.72%, 57.95% and 38.73% respectively through certain heat preservation measures. In addition, the removal efficiency of NH_(4)^(+)-N, TP and SS in the cattel-reed subsurface flow wetland was better than that in the reed-cattail subsurface flow wetland, with an increase of 3.2%, 11.1% and 6.7% percentage points, respectively. However, there was no significant difference in COD removal rate between the reed-cattel-cattail subsurface flow wetland and the cattel-reed subsurface flow wetland. It showed that different plant combinations had their own advantages in removing pollutants. In conclusion, the multi-stage composite constructed wetland had a better removal effect on pollutants, which can improve the operation efficiency of constructed wetland in winter under low temperature condition, and provide references for the promotion and application of constructed wetland in northern China.