浮水植物处理对猪场污水中可溶性有机物组成的影响

Effects of floating plants on the compositions of dissolved organic matter in swine effluent

采集江西省余江县规模化猪场污水,选取青萍(Lemna minor)、紫背浮萍(Spriodela polyrrhiza)和大薸(Pistia stratiotes)等3种浮水植物分别进行处理.通过布置4个半月的温室试验,研究浮水植物处理对污水中可溶性有机物(Dissolved organic matter,DOM)组成及其荧光特性的影响.在试验过程中,定期采样监测污水中可溶性有机碳(Dissolved organic carbon,DOC)、总氮(Total nitrogen,TN)和总磷(Total phosphorus,TP)去除效率的变化.试验结束后,收获浮水植物并测定其生物量、TN和TP浓度,以及叶绿素含量.同时,基于三维同步荧光和平行因子分析方法,对污水中DOM组分进行识别和分析.结果表明,浮萍科植物的生物量倍增时间更短,而大薸生物量和养分日累积量更大.随着培养天数的增加,浮水植物处理污水中DOC、TN和TP去除率分别达到75%、90%和80%以上,且明显高于对照处理.在猪场污水中,DOM组分主要包括一个类蛋白质组分和两个类腐殖质组分;培养初期,猪场污水以类蛋白质组分为主.随着试验天数的增加,类蛋白质组分比例呈显著降低的趋势,而类腐殖质组分逐渐增加.与对照相比,种植浮水植物显著降低污水中类蛋白质组分比例,而提高类腐殖质组分比例.此外,浮水植物处理显著降低污水DOM的新鲜度指数,而增加微生物性来源类腐殖质组分的比例.综上,浮水植物在改善猪场污水中有机养分去除效率的同时,提高了DOM组分的腐殖化程度.

In the study,swine effluent was collected from scale pig farms,located in Yujiang county of Jiangxi province. A pot experiment was carried out in a greenhouse and lasted for four and a half months. Three types of floating plants,including Lemna minor,Spriodela polyrrhiza,and Pistia stratiotes,were introduced to treat swine effluent. The main purpose of our study was to investigate the effects of floating plants on the compositions of dissolved organic matter（ DOM） and its fluorescence properties. Throughout the entire experiment,a continuous sampling was completed and the removal rates of dissolved organic carbon（ DOC）,total nitrogen（ TN）,and total phosphorus（ TP）concentration were determined. In the end,all plants were harvested to determine the biomass,TNand TP concentration,and the content of chlorophyll,respectively. Meanwhile,three-dimensional excitation-emission matrix（ 3DEEM） spectroscopy and parallel factor analysis（ PARAFAC） were applied to characterize DOM in swine effluent. Results showed that the doubling time of duckweeds biomass was shorter than P. stratiotes,while a higher biomass and daily accumulated amount of TN and TP were found in the later. With the increase in cultivated days,the removal rates of DOC,TN,and TP were over 75%,90%,and 80%,respectively,as the presence of floating plants. In swine effluent,three DOM components were identified,including one protein-like component and two humic-like components. Furthermore,protein-like component was the predominant fluorophores in original samples. During the period of experiment,the percent of protein-like component decreased dramatically,while the humic-like strengthened significantly. Compared with control,the floating plants significantly reduced the percent of protein-like component,and increased the humic-like components. Moreover,the values of fluorescence indices showed that the freshness of DOM was reduced as the remediation of floating plants,while strengthened the percent of microbial derived fulvic acids. In sum,the floating plants treatment not only improved the removal rate of organic nutrients in swine effluent,but also increased the humification degree of DOM.