【作者】 刘汉湖；

【导师】 韩宝平；

【作者基本信息】 中国矿业大学 ， 环境工程， 2010， 博士

【摘要】 通过植物—基质—微生物协同作用,人工湿地污水处理系统实现对污染物的净化,这项技术适合我国国情,具有广阔的应用前景。国内对这项技术的研究应用尚处于发展阶段,有关工艺设计资料和应用实例还不多见。本论文在系统分析国内外人工湿地研究现状基础上,针对人工湿地系统存在的“黑箱”现象,以泗洪县间歇运行的潜流式人工湿地系统为研究对象,按照系统论思想,采取现场调研与室内实验相结合方法,对人工湿地填料的理化性能和吸附作用、微生物群落结构、污染物去除效果进行定性分析与定量研究;同时,采用不确定性理论,优化人工湿地设计方法。得出的主要研究结论如下:(1)人工湿地填料理化性能测定结果表明:填料粒径越大,孔隙率越小,渗透系数越高。玄武岩填料CaO含量0.49%,沸石CaO含量4.68%;玄武岩填料大孔发育,过渡孔和小孔相对不发育,沸石填料粒径越大,大孔越发育,粒径越小,过渡孔和小孔越发育,比表面积越大。(2)玄武岩和沸石填料对氮磷静态吸附实验结果表明:沸石对氮的吸附平衡时间比玄武岩要短,对磷的吸附平衡时间两者相差不大。玄武岩对氮和磷的吸附等温线分别符合Freundlich型和Langmuir型,沸石对氮和磷的吸附等温线符合Langmuir型。沸石对氮和磷的最大吸附量大于玄武岩,沸石的吸附性能优于玄武岩。(3)填料吸附性能与理化性能有密切关系,同时,填料粒径与人工湿地床水力停留时间、水力传导性和填料吸附能力有关,据此,提出了填料最佳粒径的概念和填料吸附作用概念模型。(4)湿地床内沿程不同点位的芦苇根面、填料上的三种微生物(氨化细菌、亚硝化菌、反硝化细菌)的数量测定结果表明,无论春季、夏季还是秋季,总体来看氨化细菌>反硝化细菌>亚硝化菌;同种微生物相比,根面的微生物数量高于填料表面的数量。氨化细菌数量夏秋季比春季高1-2个数量级,沿程总体各点位数量基本在两个数量级之间变化。亚硝化菌、反硝化菌数量春夏秋季之间变化不大。(5)人工湿地水样水质监测结果表明,泗洪县潜流式人工湿地床溶解氧普遍较低,大多在0.6mg/L以下。CODCr的降解符合一级反应动力学方程,有机物在湿地前部的去除率占整个系统总去除率的80%。CODCr去除率春、夏、秋季分别为74.4%、47.7%和50.9%。(6)人工湿地系统TN、TP的去除率与季节有关,其中春季TN的去除率为64.6%,氨氮为70.7%,TP为44.1%;夏季TN的去除率为91.4%,氨氮为85.1%;秋季TN去除率为49.3%,氨氮为50.5% ,TP为13.3%。(7)泗洪人工湿地系统采用间歇运行方式,可以在一定程度上提高处理效果,三个季节监测结果表明,除了秋季外,泗洪人工湿地的出水能够满足一级B排放标准(GB18918-2002)。(8)人工湿地污水处理系统是一个存在诸多不确定性因素的复杂系统,进水水质和水量在一定范围内波动。针对污水处理厂设计过程中进水水质、水量具有不确定的特点,应用人工湿地一级动力学污染物去除模型,基于区间数理论,首次建立了以初沉池和人工湿地床为主体的污水处理系统优化设计模型。结果表明:优化模型提高了污水处理厂优化设计结果的适用性,可对人工湿地污水处理厂的设计或方案评估提供决策参考。将泗洪污水处理厂设计值与所建立的优化设计模型进行综合比较,总体来看,泗洪污水处理厂设计是科学的、合理的。更多还原

【Abstract】 Through integrated effect of plants, substrates and microorganisms, constructed wetland system can purify municipal wastewater. This technology is suitable for China, so it has wide applications and perspectives. The research and application of constructed wetland are still developing in China. So far,there are not many relative design documents and application cases.Based on systematic analyses of research status on constructed wetland in home and abroad, in view of“black box phenomenon”existing in constructed wetland system, taking Sihong intermittent subsurface flow constructed wetland (SSFCW) system as research object, according to system theory concept, using combination methods of field research and lab experiment, this dissertation studied physical-chemical properties of substrates and its adsorption, microorganism communities, removal of pollutants in SSFCW. Also, using uncertainty theory, this dissertation optimized the design method of constructed wetland system. The following conclusions were obtained.(1) The experimental results of physical-chemical properties of substrates showed that the bigger the particle size of substrates, the smaller the porosity, the higher the permeability coefficient. The mineral compositions of basalt were mainly quartz and feldspar, the content of calcium oxide was 0.49%. For zeolite, the content of calcium oxide was 4.68%. For basalt, the big holes grew well; the medium and small holes grew badly. For zeolite, the bigger the particle size, the better the big holes; the smaller the particle size, the better the medium and small holes and the bigger the specific surface area.(2) The static adsorption experiment of substrates on nitrogen and phosphorus showed that the adsorption balance time of zeolite on nitrogen was shorter than basalt; the adsorption balance time on phosphorus of both substrates was nearly equal. The adsorption isotherm of basalt on nitrogen and phosphorus were in accordance with Freundlich and Langmuir types respectively. The adsorption isotherm of zeolite on nitrogen and phosphorus were both in accordance with Freundlich type. The maximum adsorption quantity of zeolite on nitrogen and phosphorus was bigger than basalt. So, the adsorption capacity of zeolite was better than basalt.(3) There was close relationship between physical-chemical properties and adsorption capacity. Also, particle size of substrate was associated with HRT of SSFCW, permeability coefficient and adsorption capacity. Hereby, the best particle size of substrate and conceptual model of adsorption were put forward.(4) Whether in spring, summer or autumn, amounts of microorganisms on substrate surface and reed root in Sihong SSFCW showed that the amount of ammonifier was larger than that of denitrifying bacteria, and the amount of denitrifying bacteria was larger than that of nitrosomonas. For the same microorganism, the amount of bacteria on reed root was higher than that on substrate surface. In summer and autumn, the amount of ammonifier was one to two levels larger than that in spring, along the constructed wetland bed the amount of ammonifier at different points varied from one to two levels. Whether in spring, summer or autumn, the amounts of nitrosomonas and denitrifying bacteria varied little.(5) The results of water quality monitoring in SSFCW showed that the concentration of dissolved oxygen was lower than 0.6 mg/L. The kinetic equation of CODcr removal was conformed to the first order reaction. The removal rate of organic matter in first half of SSFCW accounted for 80 percent of whole constructed wetland bed. In spring, summer and autumn, the removal rates of CODcr were 74.4%, 47.7% and 50.9% respectively。(6) The removal rates of TN and TP varied from different seasons. In spring, the removal rates of TN, NH4-N and TP were 64.6%, 70.7% and 44.1% respectively. In summer, the removal rates of TN and NH4-N were 91.4% and 85.1% respectively. In autumn, the removal rates of TN, NH4-N and TP were 49.3%, 50.5% and 13.3% respectively.(7) Sihong SSFCW operated in intermittent way; this could increase the wastewater treatment efficiency. The monitoring results showed that except autumn the effluent could reach the first order B discharge standard(GB18918-2002).(8) There were many uncertain factors in constructed wetland system. The water quality and volume of influent fluctuated in some range. In view of uncertainties of water quality and volume in the deign process of wastewater treatment plant, using the first order kinetic model of pollutants removal in constructed wetland system, based on uncertainty theory, the optimization model of constructed wetland system was established. This model could increase the adaptability of wastewater treatment plant design, and provide decision-making for design of constructed wetland system. Comparing design parameters of Sihong wastewater treatment plant with the established optimization model, the design of Sihong wastewater treatment plant was scientific and reasonable.更多还原