【作者】 龚琴红；

【导师】 田光明；

【作者基本信息】 浙江大学 ， 环境工程， 2004， 硕士

【摘要】 人工湿地（Constructed Wetlands）是近年来发展起来的一种废水处理技术。它具有出水水质好，投资省（只占传统二级处理技术的10％～50％），结构简单，操作管理便利，运行费用低等特点。比较适合于资金少、能源短缺和技术人才缺乏的中小城镇和乡村。然而，现有的人工湿地技术水力负荷较小、占地面积大，氮、磷去除效率不理想。因此，寻找一种占地面积相对较小，氮和磷去除效率较高，操作管理更为方便的人工湿地新技术，成为该技术推广应用的关键。本研究针对以上现象，采用两种不同填料结构的垂直流湿地系统处理低浓度生活污水进行水力负荷研究，寻求最佳的水力负荷；为了简化操作和管理，进行了无阀垂直流湿地的设计和运行初探；采用6种不同性质的填料作为吸附剂，通过静态吸附试验和吸附动力学试验，定性定量地探讨了不同填料对磷的吸附性能，并设计了4种不同填料和填料结构的垂直流湿地小试系统进一步对填料的吸附性能进行测试。主要结果如下： 1．填料结构不同的垂直流湿地的最佳水力负荷不同。两种不同填料组合的垂直流湿地在5种水力负荷条件下的运行结果表明，双层填料湿地的最佳水力负荷为21.2cm／d，而多层填料湿地为42.4cm／d。在水力负荷为8.5cm／d，10.6cm／d，14.1cm／d，21.2cm／d的条件下，双层填料湿地和多层填料湿地对COD_Cr和NH₄⁺-N的去除无明显差异，出水COD_Cr和NH₄⁺-N浓度均低于30mp/L和5mg／L。两垂直流湿地COD_Cr净化负荷与有机污染负荷之间呈显著的正相关关系（n=42，R²＞0.98）。垂直流湿地中氮的去除主要是依靠微生物的硝化和反硝化作用；进水水质、水力负荷和温度等影响湿地系统硝化和反硝化作用的进行，水力负荷为14.1cm／d时，TN去除效率与有机污染负荷呈正相关。 运行初期人工湿地填料的结构和水力负荷对污水中磷的去除有一定的影响。水力负荷为8.5cm／d～21.2cm／d时，双层填料湿地对磷的去除效率均可达97.5％。多层填料湿地的水力负荷为8.5cm／d和10.6cm／d时，对磷的去除率可达96.3％；当水力负荷为14.1cm／d～42.4cm／d时，人工湿地对TP的去除效率随水力负荷的增大而逐渐降低，分别为92.7％，81.2％和34.5％。磷的静态吸附实验表明，填料对磷的吸附是非常有限的。填料对磷吸附未饱和前，垂直流湿地对生活污水中的磷具有良好的去除效果；填料磷吸附饱和后，去除效果较差。浙江大学硕士学位论文 2.设计了一套无阀垂直流湿地小试系统。利用该装置在冬季进行污水处理试验，结果表明:在寒冷的冬季，水力负荷为8.scn订d，黑麦草无阀垂直流湿地对有机物具有良好的去除效果，去除效率达85%，出水CODcr浓度低于50m叭;该湿地对TN的去除效果稳定，去除效率为50%;TP的去除效率随运行时间的延长而下降，为93 .5一54.2%0 3.不同填料对磷的吸附能力差异很大。钢渣对磷的吸附能力最强，且吸附速率快。6种不同填料的等温吸附曲线均能较好的符合Langmuir和Freundlich方程，单位体积填料的磷最大吸附量的顺序为:钢渣>煤渣>砂子>高炉矿渣>钨尾矿渣>碎石;FreUndlich常数n均大于1，填料对磷的吸附为优先吸附。煤渣在低磷浓度的溶液中吸附能力很弱，不适合单独作为处理生活污水的人工湿地填料;碎石的最大磷吸附量很小，对磷的吸附能力较弱。 4.不同填料结构的湿地对污水处理效果不同。几种不同填料结构垂直流湿地小试系统运行结果显示，砂子一碎石组合对CODcr、TN的去除效果较好，但除磷能力较小;而高炉矿渣一钢渣组合相反，这主要是因为强碱性的环境抑制了生物反应所致。 5.填料性质、水力负荷、污水中TP浓度影响湿地使用寿命。水力负荷为8.5cn岁d时，以钢渣和高炉矿渣为填料的#4湿地在TP浓度为1 Omg/L时，填料磷饱和吸附时间为4.05年，而以砂子和碎石为填料的#1湿地为0.38年;水力负荷为5.0c而d时，#4湿地在TP浓度为4mg/L时，填料磷饱和吸附时间可以长达16.21年，而以砂子和碎石为填料的#1湿地为1.53年。更多还原

【Abstract】 Constructed wetland is a recently developed technology of wastewater treatment. There are many advantages of this technology: high removal capacity, simple construction, low investment costs, low maintenance and operation costs, simple operation and maintenance, which is adapted to sewage treatment of village and small town absent of capital and technician. However, the current constructed wetlands have low hydraulic loading rate, low nitrogen and phosphorus removal efficiency, and occupy large ground area. The aim of this paper is to look for optimal hydraulic loading rates, simple operation and maintenance, and good substrate of constructed wetland to solute the above problems.In order to look for optimal hydraulic loading rates, two lab plants of vertical flow constructed wetland were tested to treat low concentration sewage at hydraulic loading rates of 8.5cm/d, 10.6 cm/d, 14.1 cm/d, 21.2 cm/d and 42.4 cm/d respectively. The wastewater was fed continuously. Test results indicated that CODcr and NH4+-N removal efficiency had no significant difference between multilayer substrate wetland and dual-substrate wetland, which the effluent CODcr and NH4+-N concentrations were below 30mg/L and 5mg/L, respectively. A strong function was found between CODcr removal rate and CODcr loading rate, the two parameters had significant correlativity (correlation coefficients R >0.98). Nitrogen removal mechanism analysis revealed that nitrogen in the influent was mainly eliminated through biological process via nitrification and denitrification, which were affected by water quality, hydraulic loading rate and temperature et al. There was positive correlation between TN removal efficiency and CODcr loading rate at the hydraulic loading rate of 14.1 cm/d. The ideal hydraulic loading rate of multilayer substrate wetland is 42.4 cm/d, and dual-substrate wetland 21.2 cm/d.Experimental data indicated that substrate structure and hydraulic loading rate affected TP removal at the early stage of experiment. TP removal efficiency of the dual-substrate wetland got up to 97.5% with the hydraulic loading rates of 8.5cm/d, 10.6cm/d, 14.1 cm/d and 21.2cm/d, multilayer substrate wetland 96.3% with the hydraulic rates of 8.5cm/d and 10.6cm/d. However, TP removal rates were 92.7%, 81.2% and 34.5%, respectively, with the hydraulic rates of 14.1cm/d, 21.2cm/d and 42.4cm/d, which declined following hydraulic rates rising. P-adsorption experiment results showed that P-adsorption quantity of substrate were very limited. P removalefficiency was satisfactory before substrate P-adsorption saturation, while got worse after its saturation of the two vertical flow constructed wetlands.In order to simple operation and maintenance, a small-scale plot of valveless vertical flow constructed wetland was designed, and sewage treatment experiment was taken by simulating the effluent characteristic of country sewage in winter. The experiment results indicated that valveless vertical flow constructed wetland of planted ryegrass had a significant effect on removal organic matter in winter, the removal rate of CODcr was 85% and the effluent CODcr concentration was less than 50 mg/L. The wetland system TN removal efficiency was stabilization in 50%. TP removal rate fluctuated form 93.5% to 54.2%, which declined with the extending of running period. Simple operation and maintenance of vertical flow constructed could implement.To find out the optimal substrate of constructed wetlands, equilibrium sorption experiments and kinetics sorption process of 6 substrates were carried out. The data obtained in this study were fitted to both Langmuir and Freundlich adsorption isotherms. The order of Langmuir adsorption maximum (g P/m3 substrate) was steel furnace slag(SFS) > cinder > sand > blast furnace slag(BFS) > tungsten gangue > gravel. SFS adsorption process was fast and adsorption capacity was large. But the adsorption capacity of cinder in low P concentration liquid was very weak, which was not adapted to act as the substrate of treatment sewage constructed wetlands更多还原