生态滤池—人工湿地组合工艺处理废弃沼液效果研究

发布时间：2018-12-12 10:13

【摘要】：近年来,国家和地方各级政府鼓励畜禽养殖场配套建设沼气工程,养殖污水转化为“三沼”,以减少养殖污水随意排放所带来的农业面源污染。与此同时,沼气工程产生的副产物—沼液不断增长,无法处理。本研究针对农村养殖粪污处理所产生的废弃沼液产生的环境污染问题,因地制宜,采用生态滤池-人工湿地组合工艺,通过不同水力负荷以及不同季节下组合工艺对沼液的净化效果试验,研究生态滤池-人工湿地组合工艺最佳运行参数、湿地内植物生长特性及氮磷累积效果、湿地内土壤中氮磷含量的变化。得出以下结论:(1)不同水力负荷对各个指标的去除均表现出一定的影响。COD的去除率随水力负荷的升高而先增加降低,TN、NH4+-N的去除率随着水力负荷的增加而下降,当水力负荷为0.25m3/m2 · d时,EF/CW组合工艺对各污染物都有很好的去除效果,平均去除率分别达到84.27%、66.46%、76.7%、88.46%。TP的去除率基本保持不变,说明EF/CW组合工艺对TP的去除还有一定的潜能。季节的变化对EF/CW组合工艺处理沼液各个污染物指标都有一定的影响。COD、TP的去除受季节变化的影响较大,在冬春季节无法达到排放标准时,可以降低水力负荷运行。从综合运行效果来看,EF/CW组合工艺对于COD、NH4+-N、TP都有很好的去除效果,而且具有良好的稳定性,但是对TN的去除率不甚理想,需要改进以提升TN的去除率。(2)试验期间湿地内各植物长势基本良好,不同植物的RGR差异较大,梭鱼草、水葱、美人蕉的RGR在夏季最大,之后降低,菖蒲,鸢尾、再力花的RGR则在秋季达到最大值。在表面流人工湿地系统中,湿地植物的株高、生物量、植物组织中全氮、磷含量沿水流方向呈递减的趋势,且差异显著。不同湿地植物在不同季节时期氮、磷累积量不同,基本为逐渐升高的趋势,六种植物同化吸收氮的能力大小依次为鸢尾美人蕉再力花菖蒲梭鱼草水葱。同化吸收磷的能力大小依次为菖蒲美人蕉鸢尾再力花梭鱼草水葱。说明湿地植物对氮有很好的吸收能力,在磷吸收方面,也有一定的能力。根据Tanner的方法对湿地植物进行评价,美人蕉、菖蒲对氮、磷的吸收能力比较高,再力花和鸢尾吸收能力中等,而梭鱼草、水葱的吸收能力比较差。(3)在表面流人工湿地中,植物地上部分吸收占氮去除总量的30%,土壤吸附占10%,硝化反硝化占60%。硝化反硝化作用是人工湿地脱氮的主要途径,基质吸附和植物吸收作用也是湿地脱氮的重要形式。土壤吸附磷占湿地磷去除总量的60%,是湿地除磷的主要途径。植物地上部分吸收磷占40%,在湿地除磷的过程中也起到重要作用。组合工艺的投资运行费用低,具有去污效果好、系统残渣少等特点,且管理维护方便、对人员技术要求低,适合在广大农村地区畜禽养殖场推广应用。
[Abstract]:In recent years, the national and local governments have encouraged livestock and poultry farms to build biogas projects and convert the sewage into "three marshes" in order to reduce the agricultural non-point source pollution caused by the random discharge of aquaculture sewage. At the same time, biogas engineering produced by-product-biogas liquid is growing, unable to deal with. In order to solve the problem of environmental pollution caused by waste biogas liquid produced by rural farming manure treatment, the combined process of ecological filter and constructed wetland was adopted to cope with local conditions. The optimum operation parameters, plant growth characteristics and nitrogen and phosphorus accumulation effects of the combined process of ecological filter and constructed wetland were studied through the experiments of the purification effect of biogas liquor under different hydraulic loads and different seasons. Changes of soil nitrogen and phosphorus contents in Wetlands. The following conclusions are drawn: (1) different hydraulic loads have a certain effect on the removal of each index. The removal rate of COD increases and decreases with the increase of hydraulic load, while the removal rate of TN,NH4-N decreases with the increase of hydraulic load. When the hydraulic load is 0.25m3/m2 d, the combined EF/CW process has a good removal effect on each pollutant, and the average removal rate is 84.27%, 66.46% and 76.7%, respectively. The removal rate of 88.46%.TP remains unchanged, indicating that the combined EF/CW process has a certain potential for TP removal. The seasonal variation has a certain influence on the indexes of each pollutant in the treatment of biogas liquid by EF/CW combined process. The removal of COD,TP is greatly affected by the seasonal variation. When the discharge standard can not be reached in winter and spring, the hydraulic load can be reduced. From the comprehensive operation effect, the combined EF/CW process has a good removal effect for COD,NH4 NT-TP, and has good stability, but the removal rate of TN is not very good. In order to improve the removal rate of TN, it is necessary to improve the removal rate of TN. (2) during the experiment, the growth of plants in the wetland is basically good, and the RGR of different plants is different. The RGR of barracuda, scallion and plantain is the largest in summer, and then decreases, Acorus calamus, Iris, Acorus calamus and Iris. The RGR of remanent flower reached the maximum in autumn. In the surface flow constructed wetland system, the plant height, biomass, total nitrogen and phosphorus content in plant tissue decreased along the direction of flow, and the difference was significant. The accumulation of nitrogen and phosphorus in different wetland plants was different in different seasons, which was gradually increasing. The ability of assimilating nitrogen of six species of plants was in order of Iris canna remanent calamus barracuda and Allium mongolicum. The ability of assimilating and absorbing phosphorus was followed by Acorus calamus. The results showed that wetland plants had good nitrogen absorption ability and phosphorus absorption ability. According to the evaluation of wetland plants by Tanner method, the absorption capacity of banana and Acorus calamus to nitrogen and phosphorus was high, the absorption capacity of reclaimed flower and iris was moderate, but the absorbability of barracuda and scallion was poor. (3) in the surface flow constructed wetland, Plant aboveground absorption accounted for 30% of total nitrogen removal, soil adsorption accounted for 10%, nitrification and denitrification accounted for 60%. Nitrification and denitrification are the main ways of denitrification in constructed wetlands. Substrate adsorption and plant absorption are also important forms of denitrification in constructed wetlands. Phosphorus adsorption by soil accounts for 60% of total phosphorus removal in wetland, which is the main way to remove phosphorus in wetland. The above-ground uptake of phosphorus by plants accounts for 40%, which also plays an important role in the process of phosphorus removal in wetlands. The combined process has the advantages of low cost of investment and operation, good decontamination effect, less residue of the system, convenient management and maintenance, and low technical requirements for personnel. It is suitable for popularizing and applying in livestock and poultry farms in rural areas.
【学位授予单位】：安徽农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S216.4;X713

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