【作者】 张晓红；

【导师】 常杰； 葛滢；

【作者基本信息】 浙江大学 ， 植物学， 2007， 硕士

【摘要】 人工湿地是一项运用生态学原理加上工程方法而形成的生态工程污水处理技术，是一个由生物学、水力学、水化学和物理学等过程共同构成的复杂系统，其污水处理效果受到诸多因素的影响，如水力负荷、水力停留时间、入水和出水中营养物质浓度、植被类型、水化学以及温度等。本文以位于杭州植物园等地的四个复合垂直流人工湿地为实验基地，通过对不同状况下污水净化效果的研究，进一步分析影响亚热带人工湿地污水处理过程稳定性的因素。复合垂直流人工湿地能有效改善水质且长期运行效果稳定。出水中除TN浓度较高之外，其他指标基本上能保持在国家地表水Ⅰ类或Ⅱ类水平。除BOD₅外的其他指标去除率没有逐年下降趋势，而BOD₅去除率下降（2005年以前RR＞60％，2005年之后RR＜30％）与2005年台风影响有关。该结构人工湿地对TP去除率最高（85％），BOD₅（67％）、COD（45％）和NH₄-N（59％）次之，TN（24％）和NO₃-N（16％）去除率最低。其中BOD₅和TN的去除率具有明显的季节变化，BOD₅去除率夏季最低（31％），TN伊去除率秋季最低（14％）；而氮、磷的去除效果一年四季比较稳定。植物对基质中碳、氮、磷的积累速率存在一定影响。有植物区域基质对有效氮的平均积累速率(15.73 g y^-1kg^-1干土)显著高于无植物区域(12.50 g y^-1kg^-1干土)（P＜0.05）；而有效磷的平均积累速率差异不显著，分别为3.62 g y^-1kg^-1干土和4.92 g y^-1kg^-1干土；有机碳的平均积累速率也相近，分别为0.19 g y^-1kg^-1干土和0.18 g y^-1kg^-1干土。季节动态研究表明无植物区域基质有机碳积累量夏季（0.73 g／kg干土）高于冬季（0.49 g／kg干土），有效氮积累量则冬季（53.57 g／kg干土）高于夏季（49.99 g／kg干土）；而有植物区域则没有季节变化，夏季和冬季有机碳积累量分别为0.78 g／kg干土和0.82 g／kg干土，有效氮积累量则分别为62.93 g／kg干土和64.36 g／kg干土，说明植物有助于提高人工湿地运行效果稳定性。冬季人工湿地停止运行情况时观鱼池水体中除TN含量较高之外，其他指标都接近国家地表水Ⅰ类，与运行情况下的水质差别不大。因此在处理轻度富营养化污水时冬季可以不运行。台风影响下NH₄-N和BOD₅去除率显著下降，NH₄-N去除率从64％降至15％，BOD₅去除率从48％降至8％。入水中NH₄-N浓度变化不大（0.08mg／l上升至0.11mg／l），但是BOD₅的浓度急剧增高（4.89mg／l上升至12.83mg／l），出水中则是两者的浓度都显著升高，分别从0.02mg／l和3.39mg／l上升至0.09mg／l和12.00mg／1。此外，台风期间人工湿地入水和出水的pH值下降，由中性转为偏酸性，电导率（COND）也出现显著的降低。人工湿地出水浓度随入水浓度升高而升高。MRR（物质去除量，mass removal rate）与MLR（入水负荷，mass loading rate）成正比，说明增加入水负荷有利于污染物单位面积去除量的增加。其中杭州植物园人工湿地入水BOD₅／TN＜3，COD／NO₃-N＜4，说明碳供应不足，另外三个处理重度富营养化污水的人工湿地入水BOD₅／TN＞3，COD／NO₃-N＞4，说明碳供应充足。以上研究基本确定了影响亚热带人工湿地污水处理过程稳定性的因素，为进一步优化人工湿地结构，合理配置物种模式提供了科学依据。本研究为进一步有效地提高人工湿地系统污水净化效果及其稳定性奠定了理论基础。更多还原

【Abstract】 Constructed wetlands （CWs） are engineered systems that widely used in wastewater treatment.They are complex systems in terms of biology, hydraulics and water chemistry, and treatment efficiency was affected by many factors, such as hydraulic loading rate, retention time, water column depth, influent nutrient concentration, vegetation, water chemistry and temperature. An integrated-vertical flow constructed wetland was built in Hangzhou Botanical Garden, Zhejiang Provinec, China, to purify light-eutrophic water from Jade fish-seeing pond, and other three CWs of the same structure were built to purify high-eutrophic wastewater. In this paper, in order to evaluate the stability of the function of the CW in subtropical zone, we studied annual and seasonal variations of the removal efficiency for water pollutions, and also the influence of other factors such as typoon events and the riatio of influent carbon concentration to nitrogen concentration.Integrated vertical flow constructed wetland had good purification performance and long term performance of the system was stable. Most indexes of its effluent reached or near the first class standard of Chinese surface water, such as NH₄-N, NO₃-N, TP, COD, BOD, etc. Annual variation showed no degeneration of purifying efficiency except BOD₅ in treating light-eutrophic water. The removal rate （RR） of BOD₅ gradually decreased since 2005 （before 2005 RR>60%, after 2005 RR<30%）, it might related to typhoon events. RR for TP （85%） was highest, for BOD₅ （67%）, COD （45%） and NH₄-N （59%） was a liitle lower, and RR for TN （24%） and NO₃-N （16%） was lowest.When the intergrated-flow constructed wetland was used to treat light-eutrophic wastewater, seasonal variations of RR for BOD₅ and COD was found, but no seasonal differentce in removal efficiency of nitrogen and phosphorus. RR for BOD₅ was lowest in summer （31%） and for COD was lowest in autumn （15%）.Plants in CW system play important roles in the accumulation of organic carbon, bio-available nitrogen and bio-available phosphorus in matrix. The average accumulated velocity for bio-available nitrogen in planted area (15.73 g y^-1 kg^-1 dry soil) was significantly higher than in unplanted area (12.50 g y^-1 kg^-1 dry soil) （P<0.05）. However, average accumulated velocity for bio-available phosphorus had no significant difference between planted (3.62 g y^-1 kg^-1 dry soil) and unplanted area (4.92 g y^-1 kg^-1 dry soil), and for organic carbon also showed the same average accumulated velocity, 0.19 g y^-1 kg^-1 dry soil in planted area and 0.18 g y^-1 kg^-1 in unplanted area, respectively.Seasonal variations indicated that accumulation for organic carbon in unplanted area was much higher in summer （0.73 g/kg dry soil） than in winter （0.49 g/kg dry soil）, for bio-available nitrogen was higher in winter （53.57 g/kg dry soil） than in summer （49.99 g/kg dry soil）. However, there were no significant differences among four seasons in planted area in accumulation of organic carbon and bio-available nitrogen. The accumulation for organic carbon in summer and winter was 0.78 g/kg dry soil and 0.82 g/kg dry siol, respectively. And for bio-available nitrogen was 62.93 g/kg dry soil and 64.36 g/kg dry soil, respectively. It indicated that plants in CW systems played siginificant roles in keeping stability of the removal efficiency.Water quality in the ornamental fishpond （OFP） changed little whlie CW stopped operating in winter compared to the period while kept on operating. Only TN concentration in OFP kept on a high level （Class V ） , other indexes reached or near class I standard of Chinese surface water. Consequently, CW can stop operating in winter when used to treat light- eutrophic wastewater in subtropical region.Furthermore, we taken typhoon events into consideration, results showed that removal efficiency of NH₄-N and BOD₅ decreased significantly. RR for NH₄-N decreased from 64% to 15%, and for BOD₅ decreased form 48% to 8%. Influent NH₄-N concentration varied little （increased from 0.08mg/1 to 0.11mg/1）, but effluent concentrations increased significantly from 0.02mg/l to 0.09mg/l. However, NH₄-N concentration in OFP and effluent still reached class I standard of Chinese surface water （<0.15mg/l） （GB3838-2002）. BOD₅ concentration both of the influent and effluent increased strongly, from 4.89mg/l to 12.83mg/l in influent, and 3.39mg/l to 12.00mg/l in effluent. pH value and COND both in influent and effluent were also significantly decreased.Effluent concentrations of the nutrients increased when influent concentrations rised. And massremoval rate （MRR） showed a positive relationship with mass loading rate （MLR）, which indicatedthat increase MLR can improve treatment efficiecy. The carbon supplied in CW of HangzhouBontanical Garden was inadequate （BOD₅<TN<3, COD/NO₃-N<4）, while in other three CWs thattreat high-eutrophic wastewater influent carbon source was enough （BOD₅/TN>3, COD/NO₃-NM）.The whole study analyzed the factors that influence the stability of treatment efficiency of theconstructed wetland, and provided reference for plant collocating model. This study established thetheoretical basis for the improvement in treatment efficiecy in constructed wetlands, and alsoprovided reference for treating environment with constructed wetland.更多还原