作者:王晓云,付爱民
来源:《河北工业科技》2021年第06期
摘要:为了探讨利用人工湿地处理农村污水的效益状况,以表面流人工湿地为研究对象,探析人工湿地去除污染物的运行规律。自2017年8月至2019年5月,每周采集水样一次,
共累计取样88组;分别测定SS,BOD5,TN,TP等污染物指标以及流量(Q)、水温(T),DO,pH值等运行指标;并分析了SS,BOD5,TN,TP等4种污染物的出水浓度、去除率、表面污染物负荷(PLR)分别与表面水力负荷(HLR)、水力停留时间(HRT)的相关性,以及4种污染物的一级反应速率常数(kV)与Q,HLR,HRT的相关性,最后根据线性相关性方程计算出4种污染物kV的温度修正表达式kT。研究结果发现:在采样数据范围内BOD5,TN,TP的出水浓度与HLR成正比,与HRT成反比;SS的出水浓度与HLR成反比,与HRT成正比;BOD5,TN,TP的去除率与HLR成反比,与HRT成正比;SS的去除率与HLR成正比,与HRT成反比;SS,BOD5,TN,TP的PLR与HLR成正比,与HRT成反比。SS,BOD5与TP的kV与Q,HLR正相关趋势较显著;TN的kV与HLR趋势正相关不显著,水温变化对SS的kV影响很小,水温变化对BOD5,TN,TP的kV有一定的影响。掌握表面流人工湿地污染物去除与运行参数的相关性及其反应动力学,可为研究湿地系统去除污染物机理以及在不同环境温度下工程设计参数的选择提供了理论基础。
关键词:水污染防治工程;表面流人工湿地;污染物去除;表面水力负荷;水力停留时间;表面污染物负荷;一级反应速率常数
中图分类号:X705文献标识码:ADOI: 10.7535/hbgykj.2021yx06006
Correlation between pollutant removal and operation parameters of
surface flow constructed wetland and its reaction kinetics
WANG Xiaoyun1,2,FU Aimin3
(1.College of Ecological Environment and Urban Construction,Fujian University of Technology,Fuzhou,Fujian 350008,China;2.Center for Safety and Energy Conservation Technology of Urban Water Supply and Drainage System,Fuzhou,Fujian 350008,China;3.Fujian Ningde Nuclear Power Company Limited,Ningde,Fujian 355200,China)
Abstract:In order to investigate the benefits of treating rural sewage in constructed wetland,the surface flow constructed wetland was taken as the research object to explore the operation rules of removing pollutants.From August 2017 to May 2019,88 groups of water samples were collected once a week.Pollutant indexes such as SS,BOD5,TN and TP,as well as operational indexes such as flow (Q),water temperat
ure (T),DO and pH value were measured respectively.The correlation between effluent concentration,pollutants removal efficiency,pollutants loading rate (PLR) of SS,BOD5,TN,TP and hydraulic loading rate(HLR),hydraulic retention time (HRT) was analyzed,as well as the correlation of the first-order reaction rate constants (kV) of the four pollutants with Q,HLR and HRT.Finally,according to the linear correlation equation,the temperature modified expression kT of the four pollutants kV was calculated.The results show that the effluent concentrations of BOD5,TN and TP are proportional to HLR and inversely proportional to HRT within the sampling data range.The effluent concentration of SS is inversely proportional to HLR and directly proportional to HRT.The removal rates of BOD5,TN and TP are inversely proportional to HLR and directly proportional to HRT.The removal rate of SS is directly proportional to HLR and inversely proportional to HRT.The PLR of SS,BOD5,TN and TP are proportional to HLR and inversely proportional to HRT.The positive correlation between kV,Q and HLR of TP and SS,BOD5 is significant.kV of TN is not significantly positively correlated with HLR trend,and the change of water temperature has little effect on kV of
SS,while the change of water temperature has certain effect on kV of BOD5,TN and TP.Mastering the correlation between pollutant removal and operation parameters of surface flow constructed wetlands and its reaction kinetics provides a theoretical basis for the study of pollutant removal mechanism in wetland system and the selection of engineering design parameters at different environmental temperatures.
Keywords:water pollution control engineering;surface flow constructed wetland;pollutant removal;surface hydraulic loading rate;hydraulic retention time;surface pollutants loading rate;first-order reaction rate constant
人工湿地指用人工筑成水池或沟槽,地面铺设防渗防漏隔水层,充填一定深度的基质层,种植水生植物,利用基质、植物、微生物的物理、化学、生物三重协同作用,使污水得到净化[1]。按照污水流动方式,人工湿地可分为表面流人工湿地(surface flow constructed wetland,SFCW)、水平潜流人工湿地(horizontal subsurface flow constructed wetland,HFCW)和垂直潜流人工湿地(vertical subsurface flow constructed wetland,VFCW)。表面流人工湿地由于其具有自由水面,除了满足污水净
化功能外,还可以营造景观绿化,在当前基于低影响开发(low impact development,LID)理念的海绵城市建设中,更是可以成功应用于城市雨洪控制,对于减轻城镇内涝起到重要作用。就目前的研究成果来看,人工湿地已经被当作一种有效净化污水的技术模式,得到各国的一致认可。人工湿地在农业废水、工业污水净化等方面已有大量的研究。其中,对人工湿地填料研究已经从沙子、砾石等普通基质向高炉渣、灰渣以及各种混合基质等高性能基质转变,而对于水生植物的研究也由单一植物类型向多种水生植物组合发展[2-5]。关于废水处理工艺中污染物降解的反应动力学以及微生物落的相关性分析均有研究成果[6-7]。但是由于人工湿地系统运行复杂,很多研究需要长时间的数据收集,因此对于人工湿地降解污染物的反应动力学研究并不多。
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