水平潜流湿地对城市湖泊污水的净化分析

简要介绍了人工湿地的定义、分类和发展历史及现状,以西安市兴庆湖为研究对象,在水力负荷为0.5m3/（m2.d）和水深0.7 m时,分析水平潜流湿地对城市湖泊污水中的SS、COD、氮、磷等的净化效果,为人工湿地在西北地区城市湖泊的推广应用提供借鉴。     

基质堵塞对人工湿地净化城市湖泊影响研究

以西安市兴庆湖为研究对象,研究了基质堵塞对水平潜流人工湿地净化城市湖泊水体的影响。针对利用基质进行过滤,生物量增长和分解,化学物质沉积和沉降时导致孔隙堵塞的问题,提出采用水解酸化预处理、间歇运行、药剂溶菌等方法解决。研究表明,基质堵塞问题的解决,使污水中悬浮物截流去除,可极大地提高后续湿地处理系统正常运行的可靠性。     

温度变化对人工湿地净化城市湖泊水体影响研究

以西安市兴庆湖为研究对象,对湖泊的水质进行了水平潜流和自由表面流净化的实验研究。在相同的水力负荷、水深等条件下,分析了温度变化对城市湖泊中的有机物、氮、磷等主要污染物的净化效果的影响。实验结果表明,随着水体温度的降低,湿地对各污染物的去除率呈现减少的趋势。     

季节变化对人工湿地净化城市湖泊水体的影响

以西安市兴庆湖为研究对象,研究了季节变化对人工湿地净化城市湖泊水体效果的影响.结果表明:人工湿地对污染物的去除效果受季节变化的影响较大,秋季湿地对CODCr的去除率比冬季高19.58％,对TN的去除率比冬季高33.79％,而对TP去除率的影响不明显,对NH3 -N的去除率比冬季低20.03％.     

进水浓度对人工湿地净化城市湖泊水体影响研究

以西安市兴庆湖为研究对象,实验研究进水浓度对水平潜流人工湿地净化城市湖泊水体的影响。实验参照排入西安市兴庆湖的混合污水的水质,测定了进水浓度对化学需氧量、总氮、总磷、氨氮的去除效果。结果表明:随着水力停留时间的变化,进水浓度对CODcr、TP、NH3-N的去除影响不大,CODcr、TP、NH3-N的去除率分别为79.77%,81.61%,50.66%,有较好的去除效果。而进水浓度对TN的去除有明显影响,去除率仅为27.12%。     

城市湖泊污水处理的实验分析

以西安市兴庆湖为研究对象,对湖泊的水质进行了水平潜流和自由表面流净化的实验研究,比较了两种湿地的净化效果。在相同的水力负荷、水力停留时间、水深等条件下,分析了两种人工湿地对城市湖泊中的有机物、氮、磷等主要污染物的净化效果,及不同影响因素对系统处理效果的影响,比较了两种人工湿地的优缺点。     

水力停留时间影响城市湖泊污水处理的实验分析

以西安市兴庆湖为研究对象,对湖泊的水质进行了水平潜流和自由表面流净化的实验研究,比较两种湿地的净化效果。在相同的水力负荷、水深等条件下,分析了水力停留时间对城市湖泊中的有机物、氮、磷等主要污染物的净化效果的影响。     

城市湖泊污水处理影响因素试验分析

以西安市兴庆湖为研究对象,分析了pH值和温度对人工湿地处理城市湖泊污水效果的影响。结果表明:污水pH值在7.5~8.0范围内变化,不会影响人工湿地对污染物的降解;温度对污染物去除率有很大影响,进入11月上旬时,温度下降,导致人工湿地对污染物的处理效果变差。     

改进型潜流湿地净化农村地区生活污水效果分析

基于潜流湿地结构特征和技术特点,借鉴A/O工艺污水净化原理,进行结构优化,构建改进型潜流湿地系统,并对其净化农村生活污水效果进行了试验研究。重点探讨基质层优化配置、多级湿地单元优化组合等条件对水质净化强化效果,同时考察水温对湿地系统净水效果的影响。结果表明:在水力负荷0.1 m3/(m2·d),CODCr、NH4+-N、TN和TP污染负荷分别为13.9、2.48、3.74和0.28 g/(m2·d)条件下,人工湿地系统对上述污染物去除率分别达到72.76%、76.29%、59.34%和89.39%,出水基本可满足DB 11/307-2013《北京市水污染物排放标准》中新建村庄生活污水处理站排入地表水体污染物排放限值中的B标准(CODCr≤40mg/L、TN≤15 mg/L、NH4+-N≤5(8)mg/L及TP≤0.4 mg/L)。     

北方潜流人工湿地水质梯级净化能力分析

潜流人工湿地是人工湿地的主要类型,湿地梯级净化效果需要进一步研究。以官厅水库黑土洼地湿地系统示范工程为研究对象,通过近4 a实验,总结得出湿地对各类污染物的梯级净化效果。分析结果表明,人工湿地示范工程对水质净化效果较为明显,各个主要污染物的去除率平均达到40％以上;前两级湿地污染物的去除率占总去除率的比例大部分达到50%以上;潜流人工湿地具有进一步净化水质的潜力。基于分析结果,对于北方人工湿地的建设提出了有指导价值的建议,并指出了今后的研究方向。     

Development of a horizontal subsurface flow modular constructed wetland for urban runoff treatment

Constructed wetlands (CWs) are well recognized as having low construction and maintenance cost and low energy requirement. However, CW design has been mainly based on rule-of-thumb approaches. In this study, the efficiency of a modular horizontal subsurface flow (HSSF) CW using four different design schemes was investigated. Based on the results, the four systems have attained more than 90% removal of total suspended solids and more than 50% removal efficiency for total phosphorus, PO(4)-P and Zn. The planted system achieved higher pollutant removal rates than the unplanted system. In terms of media, bottom ash was more effective than woodchip in reducing the pollutants. Considering the flow length, optimum removal efficiency was achieved after passing the sedimentation tank and vertical media layer; with respect to depth, more pollutants were removed in the upper sand layer than in the lower gravel layer. This study recommended a surface area of 0.25 to 0.8% of catchment area for planted CW and 0.26 to 0.9% for unplanted CW using the 7.5 to 10 mm design rainfall.     

三段式水平潜流人工湿地的中试研究

采用三段式水平潜流人工湿地处理生活污水,具有较强的抗污染负荷冲击能力,出水水质可达GB 18918—2002一级A标准。人工湿地对COD_(Cr)的去除规律符合一级反应,COD_(Cr)与长度的关系为C_i-C_*=90.356L~(-0.5201)。     

北京未来科技城滨水森林公园潜流人工湿地净化效果对比研究

以北京未来科技城滨水公园的潜流人工湿地为研究对象,在5个试验单元中,分别选用焦炭、沸石、火山岩、砾石和生物质焦作为填料,比较了不同试验单元对水体净化效果的差异。研究结果表明,潜流人工湿地可以有效地去除河水中的氮、磷、有机污染物,针对不同水质要求和修复目标,应选用适当的填料基质。     

The effect of the scale of horizontal subsurface flow constructed wetlands on flow and transport parameters.

Horizontal subsurface flow constructed wetlands have proven their efficiency in treating wastewater and removing the pollutants of concern. Treatment efficiency depends on the wastewater residence time, which is a function of the hydraulic loading and the physical conditions of the constructed filter system, which can be described with effective parameters such as: hydraulic conductivity, porosity, dispersivity etc. Because spatial variability is often scale dependent, these effective parameters may be affected by the scale of the system being studied. In this paper the results of tracer experiments in constructed filters using saturated horizontal flow at three scales (small and medium lab scales and full-scale system) using the same filter media is reported. Light-weight aggregate (filter media termed Filtralite-P) was used at all scales. Increasing the scale was associated with increasing dispersivity, meanwhile hydraulic conductivity experienced dramatic reduction and variation by increasing the examined scale. Observed changes in the hydraulic parameters indicate that heterogeneity at different scales should be taken into account when the performance of LWA filters are evaluated from small-scale experiments.     

潜流人工湿地对污染物去除率的正交实验研究

以湿地污染物去除率为考察指标,通过正交实验分析了植物、流量和水位对去除率的影响。结果表明：3种因素对BOD5、CODMn和TN去除率的影响一致,均为植物〉流量〉水位;植物是BOD5、CODMn和TN去除率的显著性影响因素,其中大薸对3种污染物的去除率显著高于凤眼莲,但其在9月底易发生二次污染,需要及早收割,流量是TN和CODMn去除率的显著性因素,水位为不显著因素;BOD5、CODMn和TN浓度在系统的前端下降速率较大,随后逐渐减小并趋于平稳,表明大部分污染物在湿地的前端被去除,湿地整体截污能力尚有较大提升空间。应用中可选择大薸在北方推广,并充分利用湿地后端潜能,最大化处理污染源水体。     

进出水口位置对潜流人工湿地水力效率及死区分布的影响

将模拟人工湿地装置分别设置3个进水口(上、中、下)和3个出水口(上、中、下),通过氯化钠NaCl脉冲示踪实验研究了这9种不同进出水口配置的停留时间分布曲线,分别计算出它们的水力效率,并进行了评价。同时通过同一透明装置的染料示踪实验,获得其染料运移图像,并根据图像处理获得模拟人工湿地装置中水流运移轨迹和死区分布情况,从而对上述水力效率评价结果进行了直观验证。结果表明:下进上出的水力效率最高,下进下出的水力效率最低。进一步的图像分析表明,下进上出的死区最小,下进下出的死区最大。分析表明:人工湿地的进出水口位置对其水力停留时间、死区等会产生关键影响,从而导致其水力效率的变化,进而可能通过影响水流中污染物和填料基质的接触过程而导致水中污染物去除效率的变化。     

潜流式人工湿地的数值模拟与参数率定

以沈阳辉山明渠河口潜流式人工湿地为例,利用数值模拟预测了该湿地的运行效果。采用多孔介质水流与溶质运移耦合模型,通过对湿地模型的概化与处理,利用FEFLOW软件针对潜流基质层的水流和溶质扩散进行数值模拟,通过敏感度分析确定基质层的孔隙度、渗透系数、弥散系数和吸附降解系数为影响污水处理效果的敏感参数,并通过参数率定对所建立的湿地模型进行了模拟预测,结果证明所构建的湿地模型的预测值与观测值拟合程度较好。可为潜流式人工湿地设计中运行效果预测及参数设定提供一种新的有效方法。     

Effect of dosing regime on nitrification in a subsurface vertical flow treatment wetland system

In this study, the effect of dosing regime on nitrification in a subsurface vertical flow treatment wetland system was investigated. The experimental unit was composed of four circular concrete tanks (1 m diameter and 80 cm deep), filled with gravel (1-2 cm) and planted with Cyperus alternifolius L. Synthetic wastewater with average chemical oxygen demand (COD) and ammonia nitrogen of 1,151 and 339 mg/L was fed into each tank. Different feeding and resting periods were applied: continuous flow (tank 1), 4 hrs on and 4 hrs off (tank 2), 1 hr on and 3 hrs off (tank 3) and 15 minutes on and 3 hrs 45 minutes off (tank 4). All four tanks were under the same hydraulic loading rate of 5 cm/day. After 165 days the reduction of total Kjeldahl nitrogen and ammonia nitrogen and the increase of nitrate nitrogen were greatest in tank 4, which had the shortest feeding period, while the continuous flow produced the lowest results. Effluent tanks 2 and 3 experienced similar levels of nitrification, both higher than that of tank 1. Thus supporting the idea that rapid dosing periods provide better aerobic conditions resulting in enhanced nitrification within the bed. Tank 4 had the highest removal rates for COD, and the continuous flow had the lowest. Tank 2 also exhibited a higher COD removal rate than tank 3, demonstrating that short dosing periods provide better within-bed oxidation and therefore offer higher removal efficiency.     

暗管排水条件下人工湿地的环境效应分析

通过室内人工模拟湿地试验和野外湿地试验,分析了暗管排水条件下人工湿地的环境效应。结果表明:1、在室内人工模拟湿地试验中,除了池塘水流湿地对总氮的截留率只有33%以外,两种类型湿地对氮、磷的截留效率均在50%以上,且回形水流湿地对农业污染物的截留作用更为明显;2、在野外湿地试验中,5种湿地对水体全氮的平均去除率分别为42.2%、50.4%、61.5%、52.0%和63.5%,5种湿地对水体全磷的去除率分别为54.6%、60.1%、64.8%、61.9%和68.2%,5种湿地对全磷的去除率都在50%以上。通过综合分析可知,暗管排水条件下,人工湿地对氮元素和磷元素的去处效率都很高,有利于生态环境的保护。