基于动力学的尾水湿地污染物去除效果研究

POLLUTANTS REMOVAL EFFECT OF THE TAIL WATER WETLAND BASED ON KINETICS

城市污水处理厂配套尾水湿地可深度处理污水并营造良好景观效果。以长江流域某沿江城市污水处理厂尾水湿地为研究对象,构建湿地反应动力学模型,计算湿地反应速率常数,分析湿地去污效果,探索去污效果影响因素,据此提出湿地效率提升建议。结果表明:尾水湿地氨氮、总磷反应动力学模型参数θ分别为1.08及1.03,k_(A,20)分别为0.41m/d和0.09 m/d,k_(V,20)分别为0.37/d和0.08/d;来水污染物负荷显著影响湿地微生物动力学过程;氨氮和总磷的平均去除率分别为63.65%和31.87%,出水水质满足设计要求;氨氮及总磷去除率随污染物负荷增大显著升高;污水处理厂在满足出水水质达标要求下,提高尾水湿地进水污染物负荷,可促进湿地内微生物反应,提升污染物去除率,推进污水处理绿色低碳发展。

The tail water wetlands(TWWs),the ancillary facilities of the municipal wastewater treatment plants(WWTPs),can deeply treat wastewater with created comfortable landscapes.The TWW accompanying a WWTP located in a riverine city in the Yangtze River Basin was taken as a case study.Kinetic models of the TWW were constructed to calculate the reaction rate constants.The imported and exported water quality was analyzed to explore the removal effect of pollutants.Therefore,the factors affecting the decontamination effect of the TWW was revealed and the efficiency improvement was proposed accordingly.The results showed that the reaction kinetic model parameters,θvalues of ammonia nitrogen and total phosphorus in the TWW were 1.08 and 1.03,k_(A,20)were 0.41 m/d and 0.09 m/d,k_(V,20)were 0.37/d and 0.08/d,respectively.The pollutant loads of the imported water significantly affected the microbial kinetic processes in the TWW.The average removal rates of ammonia nitrogen and total phosphorus were 63.65%and 31.87%,respectively,and the effluent water quality meets the design requirements.The removal rates of ammonia nitrogen and total phosphorus increased significantly with the increased of the pollutant loads.It is suggested that the terminal effluent of WWTP should provide plenty of organic and nutrient loads imported into the TWW,while meeting the effluent water quality standard requirements,which will promote microbial reactions in the TWW,and enhance the pollutant removal rates,on the all,promote the green and low-carbon development of wastewater treatment.