垂直-水平流人工湿地系统除污效果研究

以武汉汉阳桃花岛城市面源污染控制示范工程为依托,研究示范工程中垂直—水平流人工湿地系统对生活污水的净化效果。结果表明,在人工湿地水力停留3 d的情况下,垂直—水平流人工湿系统对COD、SS、TP和TN均具有明显去除效果。其中,对COD、SS的去除率主要位于垂直流阶段,对TP和TN的去除率主要位于水平流阶段。水平流湿地中,种植黄花美人蕉的湿地单元对COD、TP和TN处理效果略高于种植鸢尾和红花美人蕉的湿地单元。     

垂直流人工湿地系统保护饮用水源的实例

简述了复合垂直流人工湿地污水处理系统专有技术的由来,并结合石岩人工湿地一期工程叙述了垂直流人工湿地的工艺原理、技术特点、植物特点、处理效果等,结果表明采用垂直流人工湿地生态污水处理系统保护饮用水源,能达到污水净化和美化环境的“双赢”目标。     

浅谈垂直流人工湿地在珠江三角洲地区的发展

目前珠江三角洲地区水资源呈现水质性缺水，河湖（库）水污染随着经济社会的发展而日趋严重，迫切需要有好的保护措施来解决缺水和水污染问题。人工湿地是近年来发展较快的一种生态治污技术，经处理后的水资源可持续利用。其中的垂直流人工湿地具有高效节能、出水水质好、投资省运行费用低、占地面积小、能改善生态环境等优点，具有广阔的发展前景。     

复合垂直流人工湿地对北方污染水净化效果

针对冬夏气温变化较大的北方一年内的污染水去除率变化较大,为保证污染水一年内有较高且相对均衡的去除率,对沉淀池采取一池两用,结合复合垂直流人工湿地,对污染水进行处理,从理论上提出了本工艺的流程。     

浅谈垂直流人工湿地在珠江三角洲地区的发展

目前珠江三角洲地区水资源呈现水质性缺水,河湖(库)水污染随着经济社会的发展而日趋严重,迫切需要有好的保护措施来解决缺水和水污染问题。人工湿地是近年来发展较快的一种生态治污技术,经处理后的水资源可持续利用。其中的垂直流人工湿地具有高效节能、出水水质好、投资省运行费用低、占地面积小、能改善生态环境等优点,具有广阔的发展前景。     

垂直流人工湿地对河涌污水的处理效果研究

研究垂直流人工湿地系统在珠江三角洲城市河涌污水净化中的作用。以广州市猎德涌为例,采用芦苇、风车草、宽叶香蒲、美人蕉4种不同植物构成的垂直流人工湿地对污水中NH4^＋—N、CODcr及TP的去除进行实验研究。结果表明,在水力停留时间3d、连续进水的情况下,4种植物对CODcr的去除效果差异性不是很显著。     

垂直流人工湿地系统在城市生活小区污水处理和回用中的应用

本文以深圳市万科东海岸垂直流人工湿地工程在城市生活小区污水处理回用中的应用为例,分析了垂直流人工湿地对污水中CODcr、BOD5、NH3-N、PO4-P的去除效果,并阐述了污染物的去除机理．结果表明采用垂直流人工湿地系统对城市生活小区污水处理回用,不仅出水水质好,而且美化了环境。     

表面流人工湿地控制农田排水污染物的作用

南方早稻期间降雨多,农田排水多、面源污染严重.为了研究生态修复技术对南方早稻期间农田排水中氮磷污染物的净化效果,本试验在广西桂林青狮潭灌区农田灌溉区域中,地势低洼处建立表面流人工湿地对农田排水进行处理.2009～2010年,早稻期间定时检测农田排水中氮磷污染物的变化情况及表面流人工湿地对氮磷污染物的去除效果,结果表明:2009～2010早稻期间,表面流人工湿地对总氮去除率分别为43.11%、48.95%;总磷的去除率分别为54.23%、43.28%,去除效果较好.     

沸石床复合垂直流人工湿地脱氮机理分析

通过研究沸石床复合垂直流人工湿地中不同形态氮的空间变化,分析了其脱氮机理,认为沸石对NH_3—N的吸附作用是脱氮的重要途径,硝化和反硝化作用提高了TN的去除率,硝化和反硝化强度影响到沸石的饱和周期和生物再生,有待进一步研究。     

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。     

Diversity of ammonia oxidising bacteria in a vertical flow constructed wetland.

Vertical flow constructed wetlands (VFCWs) with intermittent loading are very suitable for nitrification. Ammonia oxidising bacteria (AOB) are the limiting step of nitration. Therefore the AOB community of a full-scale VFCW, receiving municipal wastewater, was investigated within this study. The diversity of the functional gene encoding the alpha-subunit of the ammonia monooxygenase (amoA), present only in AOB, was assessed by denaturing gradient gel electrophoresis (DGGE). Only very few amoA sequence types dominated the wetland filter substrate; nevertheless a stable nitrification performance could be observed. During the cold season the nitrification was slightly reduced, but it has been shown that the same AOB could be identified. No spatial AOB pattern could be observed within the filter body of the VFCW. The most prominent bands were excised from DGGE gels and sequenced. Sequence analyses revealed two dominant AOB lineages: Nitrosomonas europaea/"Nitrosococcus mobilis" and Nitrosospira. Species of the Nitrosomonas lineage are commonly found in conventional wastewater treatment plants (WWTPs). In contrast, members of the Nitrosospira lineage are rarely present in WWTPs. Our observations indicate that the AOB community in this VFCW is similar to that found in horizontal flow constructed wetlands, but differs from common WWTPs regarding the presence of Nitrosospira.     

Simulation of a subsurface vertical flow constructed wetland for CSO treatment.

Constructed wetlands (CWs) have proved to be a highly effective measure to reduce the ecological impact of combined sewer overflows (CSOs) on receiving waters. Due to the stochastic nature of the loading regime and the multitude of environmental influences, assessment of the performance of such plants requires detailed mathematical modelling. A multi-component reactive transport module (CW2D) was applied to simulate the flow, transport and degradation processes occurring in a CW for CSO treatment. CW2D was originally developed to simulate the treatment of municipal wastewater in subsurface flow CWs. Loading and operational conditions in CSO treatment differ fundamentally from the conditions occurring for wastewater treatment. Despite these differences, first results from the simulation of lab-scale experiments show, that the model is generally applicable to this type of plant. Modelling of adsorption, degradation processes, and influent fractionation, however, require further research.     

Treatment of high strength wastewater with vertical flow constructed wetland filters.

The aim of the present study was to evaluate the behaviour of vertical flow constructed wetlands to treat high strength wastewater. Influents were obtained mixing tap water with different percentages of MSW landfill leachate (5%, 10% and 20%). Phragmites australis seedlings were used as macrophytes. The reeds were nurtured during three spring months, before the start of the experimental period. Three and four days of detention time were adopted. Influent concentrations of 510-2,050 mg L(-1), 180-740 mg L(-1) and 65-260 mg L(-1) were obtained for COD, N-NH4(+) and N-NO3(-), respectively. The environmental temperature averaged around 31.0 +/- 1.4 degrees C. During the experimental period, all parameters showed an increasing removal efficiency trend. Best results in terms of COD removal were obtained for mixtures at lowest rate of landfill leachate; while, denitrification process showed an opposite behaviour; finally, the removal of ammonia nitrogen appeared to be independent upon influent concentrations. Analysis carried out on the reed tissues showed a theoretic maximum storage of TKN in the leaves of about 55 mg/g dry weight. A leachate percentage of about 35% was derived to be able to fully inhibit the growth of macrophytes.     

A two-stage subsurface vertical flow constructed wetland for high-rate nitrogen removal.

By using a two-stage constructed wetland (CW) system operated with an organic load of 40 gCOD.m(-2).d(-1) (2 m2 per person equivalent) average nitrogen removal efficiencies of about 50% and average nitrogen elimination rates of 980 g N.m(-2).yr(-1) could be achieved. Two vertical flow beds with intermittent loading have been operated in series. The first stage uses sand with a grain size of 2-3.2 mm for the main layer and has a drainage layer that is impounded; the second stage sand with a grain size of 0.06-4 mm and a drainage layer with free drainage. The high nitrogen removal can be achieved without recirculation thus it is possible to operate the two-stage CW system without energy input. The paper shows performance data for the two-stage CW system regarding removal of organic matter and nitrogen for the two year operating period of the system. Additionally, its efficiency is compared with the efficiency of a single-stage vertical flow CW system designed and operated according to the Austrian design standards with 4 m2 per person equivalent. The comparison shows that a higher effluent quality could be reached with the two-stage system although the two-stage CW system is operated with the double organic load or half the specific surface area requirement, respectively. Another advantage is that the specific investment costs of the two-stage CW system amount to 1,200 EUR per person (without mechanical pre-treatment) and are only about 60% of the specific investment costs of the singe-stage CW system.     

Nitrogen removal and ammonia-oxidising bacteria in a vertical flow constructed wetland treating inorganic wastewater

Nitrogen removal performance and the ammonia-oxidising bacterial (AOB) community were assessed in the batch loaded 1.3 ha saturated surface vertical flow wetland at CSBP Ltd, a fertiliser and chemical manufacturer located in Kwinana, Western Australia. From September 2008 to October 2009 water quality was monitored and sediment samples collected for bacterial analyses. During the period of study the wetland received an average inflow of 1,109 m3/day with NH3-N = 40 mg/L and NO3-N = 23 mg/L. Effluent NH3-N and NO3-N were on average 31 and 25 mg/L, respectively. The overall NH3-N removal rate for the period was 1.2 g/m2/day indicating the nitrifying capacity of the wetland. The structure of the AOB community was analysed using group specific primers for the ammonia monooxygenase gene (amoA) by terminal restriction fragment length polymorphism and by clone libraries to identify key members. The majority of sequences obtained were most similar to Nitrosomonas sp. while Nitrosospira sp. was less frequent. Another two vertical flow wetlands, 0.8 ha each, were commissioned at CSBP in July 2009, since then the wetland in this study has received nitrified effluent from these two new cells.     

Interaction of oxygen concentration and retention of pollutants in vertical flow constructed wetlands for CSO treatment.

The EU Water Framework Directive (WFD) calls for a good quality of all water bodies. Retention soil filters (RSF) have been developed to treat discharges from combined sewers systems. RSF have proved over the past 15 years to be the most effective measure to meet the EU WFD standards, especially for small or particularly sensitive receiving waters, which require an enhanced reduction of emissions from combined sewer overflows (CSOs). The paper presents results from laboratory-scale experiments, in which the oxygen measurement in the filter plays a main role. The results show remarkable differences in oxygen concentrations in different filter depths. The highest oxygen consumption takes place in the upper part of the filter. In the lower part the re-aeration of sewage from the soil air dominates. This indicates that the biological activity is limited to the upper part of the filter. The availability of oxygen in the filter is a sign for degradation of wastewater compounds (ammonium, COD) under certain conditions and already takes place during the filter operation. The removal of ammonium especially cannot be strictly divided into phases of sorption during the loading and oxidation during the dry period any more.     

The effect of a vertical flow filter bed on a hybrid constructed wetland system.

Data from 18 sampling wells in Kodij?rve horizontal subsurface flow (HSSF) constructed wetland (CW) (South Estonia) is presented and differences in purification efficiencies inside the HSSF CW are calculated. Temporarily anaerobic conditions in the Kodij?rve HSSF system did not allow efficient removal of BOD7, NH4-N, Ntot and Ptot. In 2002 a vertical subsurface flow filter was constructed to enhance aeration. The design of the system was based simply on the oxygen demand of the wastewater and on the aeration potential of vertical flow wetlands. The vertical flow system has shown satisfactory results. The purification efficiency of BOD7 in the Kodij?rve CW has improved significantly and there has been a slight increase in purification efficiencies of NH4-N and Ntot. On the ohther hand, the removal efficiency of Ptot has decreased significantly. Although, the mass loading rates have increased, mass removal rates of all four parameters have improved significantly. Nevertheless, optimization of the constructed wetland system is essential in order to meet effluent standards during wintertime.     

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)。     

Vertical flow constructed wetland for textile effluent treatment.

A pulse feed vertical flow constructed wetland (VFCW) proved to be efficient in the treatment of a textile effluent being able to buffer, dilute and treat an Acid Orange (AO7) accidental discharge. The influence of the flooding level (FL) and pulse feed (PF) duration on the removal efficiencies of a VFCW was examined. Average AO7 removal efficiencies of 70% were achieved for an AO7 Inlet concentration of 700 mgl(-1) applied during 15 min cycle(-1) (every three hours) at a hydraulic load of 13 lm(-2) cycle(-1) and an FL of 21%. The VFCW was modelled by analogy with a combination of ideal reactors. The simplest combination that best reproduced the experimental results was an association of 2 reactors in series plus 1 reactor accounting the dead volumes. The model parameters helped to understand the hydrological and kinetic processes occurring in VFCW. Through the model simulation it was shown that 3 VFCW in series were enough to efficiently treat an organic mass load of 76 gAO7 m(-2) day(-1) in 9 hours and fulfil the discharge legislation. In this work it was possible to establish that the overall degradation kinetics was of first order.     

Microbial diversity and community composition in recirculating vertical flow constructed wetlands

Microorganisms constitute a central component of constructed wetlands (CWs), playing a major role in these systems' capacity for treating wastewater. The aim of this study was to determine the diversity and composition of the microbial community found in a recirculating vertical flow CW (RVFCW) bed fed with primarily settled domestic wastewater and its response to the presence of plants, season and location in the bed. The RVFCW removed 90-95% of TSS and BOD(5) to below 10 mg L(-1). The effluent quality was not significantly affected by seasonal temperature or the existence of plants in the bed. None of these factors had discernible effects on bacterial diversity, e.g. in the planted RVFCW, the richness (S') and Shannon-Weiner diversity (H') indices were 18.3 (±3.5) and 2.49 (±0.15), respectively, which are similar to the values of 19.4 (±3.5) and 2.57 (±0.18) in the unplanted RVFCW. However, there were indications that the structure of the microbial community underwent changes that were uncorrelated with the environmental factors tested and that did not affect the overall performance. The consistency in diversity and composition/structure of the bacterial community in the face of temporal and environmental influences possibly contributes to the robustness and high treatment capacity of the RVFCW system.