水平潜流和垂直流湿地处理蓟运河水的效果比较

为了改善蓟运河的水质,使其达到《地表水环境质量标准》(GB 3838—2002)中的Ⅳ类水质标准,在蓟运河北岸的空地上构建了水平潜流人工湿地和垂直流人工湿地,研究了其对河水的净化效果。为防止浮游藻类堵塞填料床,原水在进入人工湿地前先经加药气浮工艺预处理,当PAC的投加量为50 mg/L时,水平潜流人工湿地对COD、BOD5、SS、TN、NH3-N、TP的去除率分别为65%、50%、100%、70%、90%和65%,垂直流人工湿地对COD、BOD5、SS、TN、NH3-N、TP的去除率分别为45%、70%、100%、65%、95%、85%。两种人工湿地的出水水质均可以达到Ⅳ类标准,但考虑到冬季低温时,垂直流人工湿地的填料床极易发生冰冻的现象,所以建议采用水平潜流人工湿地处理蓟运河水。     

用于净化景观水体水质的人工湿地设计

介绍了用于景观水体水质净化的人工湿地系统的工艺流程及设计方法，具体包括进行循环处理的人工湿地的设计、处理补充水的人工湿地的设计以及湿地几何尺寸的确定方法。该方法适用于以雨水或再生水为补充水源的人工景观水体水质净化工程。     

不同湿地植物对扎染废水处理效果的研究

分别以芦苇、美人蕉、菖蒲和水芹菜为湿地植物来构建垂直潜流人工湿地系统,研究其对扎染废水的处理效果.结果表明,在相同进水浓度下,芦苇湿地系统的出水COD平均浓度最低,仅为25.7 mg/L;美人蕉湿地系统的出水氨氮和TN平均浓度最低,分别为0.96和4.25 mg/L;水芹菜湿地系统的出水TP平均浓度最低,仅为0.09 mg/L.综合考虑可知,芦苇和美人蕉对扎染废水的处理能力较强.4种植物对扎染废水均具有较好的处理效果,湿地出水的各项指标均优于<城镇污水处理厂污染物排放标准>(GB 18918-2002)的一级A标准.     

两种改进型垂直潜流人工湿地脱氮途径分析研究

通过对两种改进型垂直潜流人工湿地中垂向沿程DO浓度、氨氮浓度以及硝态氮浓度的考察,从pH角度分析了两种改进型湿地中的脱氮途径.试验发现,两种改进型垂直潜流人工湿地均能满足硝化要求,出水氨氮浓度均能达到<城镇污水处理厂污染物排放标准>(GB 18918-2002)的一级A标准,且改进型序批式垂直潜流人工湿地(MCBW)的脱氮能力大于序批式垂直潜流人工湿地(CBW).此外,通过理论分析和物料衡算得出,序批式垂直潜流人工湿地的脱氮途径主要以传统硝化反硝化为主,而改进型序批式垂直潜流人工湿地中存在着同步硝化反硝化.     

人工湿地在生态住宅小区建设中的应用

人工湿地处理技术具有投资低、出水水质好、耗能低、抗冲击力强、操作简单和运行费用低等优点,本文介绍了用于景观水体水质净化的人工湿地系统的工艺流程及设计方法,该方法适用于以雨水或再生水为补充水源的人工景观水体水质净化工程。     

人工湿地堵塞问题的探讨

近20年发展起来的人工湿地,作为一种对传统污水处理技术的廉价替代方案,越来越受到世界各国的普遍重视.通过对人工湿地运行过程中出现的填料堵塞现象进行全面分析,归纳和总结了人工湿地堵塞的影响因素,对其堵塞机理和堵塞模型进行了探讨,提出了避免堵塞的工程化解决措施和湿地堵塞后的恢复方法.     

细数植物在人工湿地污水处理中的作用

天然的湿地植物在形态和解剖学上均能适应氧含量较低的生态环境,因此,它们可用于人工湿地系统中处理污水。而人工湿地中的植物不仅将人工湿地与稳定塘区分开,同时为污染物的去除创造适合的条件。人工湿地中的植物不仅能减弱强光与风力对湿地的影响,为湿地基质提供保温作用,满足根区微生物生长对氧气和其他营养成分的需求,还能截留部分污染物预防湿地堵塞,并具有其特有的美学价值,在不同类型的人工湿地中发挥不同程度的作用。最常见的人工湿地植物有漂浮植物如凤眼莲、浮萍;沉水植物如狐尾藻属、金鱼藻属;挺水植物如芦苇、香蒲属。而国内人工湿地除了以上这些常见植物外,还常用一些其他的沉水植物,比如芦竹、再力花、风车草以及美人蕉等。     

Effect of plant species on water quality at the outlet of a sludge treatment wetland

Sludge treatment wetlands are mainly used to reduce the volume of activated sludge, and the pollutants at the outlet are generally returned to the wastewater treatment plant. However, in cases where sludges are produced far from treatment plants not only must the sludge be treated, but the discharge of pollutants into the surrounding environment must also be limited. The aim of this study was to evaluate the efficiency of different plant species in optimising pollutant removal in a decentralised sludge treatment wetland. In addition, a new system design was assessed, in which the wetland was not completely drained, and a saturated layer was created using an overflow. The experimental setup consisted of 16 mesocosms in total, planted with monocultures of Phragmites australis, Typha angustifolia and Scirpus fluviatilis, and unplanted controls, each in four replicates.The experiment was conducted during the third summer of operation after setup. The system was fed with highly concentrated fish farm sludge at a load of 30 kg of total solids m⁻² yr⁻¹. Results showed that such wetlands were highly efficient, with removal rates between 94% and 99% for most pollutants. Planted systems generally outperformed the unplanted control, with a significantly lower mass of pollutants at the outlet of the sludge treatment wetland planted with Phragmites, followed by those with Typha and then Scirpus. The distinct influence of plant species on pollution removal was explained by the sequestration of nitrogen and phosphorus in plant tissues and by the rhizosphere effect, which enhance the biodegradation of organic matter, allowed the nitrification process and created redox conditions favourable to the sorption of phosphorus. Filtration and evapotranspiration rates played a major role in limiting the discharge of pollutants, and the impact was enhanced by the fact that the sludge treatment wetland was not completely drained.     

Treatment of landfill leachate using an aerated, horizontal subsurface-flow constructed wetland

A pilot-scale subsurface-flow constructed wetland was installed at the Jones County Municipal Landfill, near Anamosa, Iowa, in August 1999 to demonstrate the use of constructed wetlands as a viable low-cost treatment option for leachate generated at small landfills. The system was equipped with a patented wetland aeration process to aid in removal of organic matter and ammonia nitrogen. The high iron content of the leachate caused the aeration system to cease 2 years into operation. Upon the installation of a pretreatment chamber for iron removal and a new aeration system, treatment efficiencies dramatically improved. Seasonal performance with and without aeration is reported for 5-day biochemical oxygen demand (BOD(5)), chemical oxygen demand (COD), ammonia nitrogen (NH(4)-N), and nitrate nitrogen (NO(3)-N). Since winter air temperatures in Iowa can be very cold, a layer of mulch insulation was installed on top of the wetland bed to keep the system from freezing. When the insulation layer was properly maintained (either through sufficient litterfall or replenishing the mulch layer), the wetland sustained air temperatures of as low as -26 degrees C without freezing problems.     

Performance comparison of constructed wetlands with gravel- and rice husk-based media for phenol and nitrogen removal

This study aims to compare the performance of planted and unplanted constructed wetlands with gravel- and raw rice husk-based media for phenol and nitrogen removal. Four laboratory-scale horizontal subsurface-flow constructed wetland units, two of which planted with cattail (Typha latifolia) were operated outdoors. The units were operated at a nominal hydraulic retention time of 7 days and fed with domestic wastewater spiked with phenol concentration at 300 mg/L for 74 days and then at 500 mg/L for 198 days. The results show that planted wetland units performed better than the unplanted ones in the removal and mineralization of phenol. This was explained by the creation of more micro-aerobic zones in the root zone of the wetland plants which allow a faster rate of phenol biodegradation, and the phenol uptake by plants. The better performance of the rice husk-based planted wetland compared to that of the gravel-based planted wetland in phenol removal could be explained by the observation that more rhizomes were established in the rice husk-based wetland unit thus creating more micro-aerobic zones for phenol degradation. The role of rice husk as an adsorbent in phenol removal was considered not of importance.     

Constructed Wetlands: A Strategy for Sustainable Wastewater Treatment at Small Treatment Works

The use of sub-surface flow constructed wetlands planted with Phragmites australis (the common reed) for the treatment of sewage is now widespread in the UK. The strategy for the use of reed-beds by a major UK water utility is reviewed in terms of whether the process (a) is appropriate within the rural environment, (b) offers satisfactory performance, and (c) meets criteria for sustainability. Its use for secondary, tertiary and storm-water treatment is considered. Odour generation has been a concern for secondary treatment reed-beds and has been measured and modelled to identify the required minimum distance to properties to eliminate any possibility of odour nuisance.     

潜流人工湿地预处理给水厂原水的效能研究

采用潜流人工湿地对给水厂原水进行预处理,以提高进水水质,减轻水厂常规处理工艺的负荷。以松花江水为研究对象,考察了人工湿地对原水中浊度、CODMn、UV254、TN和NH4^＋-N的处理效果。试验结果表明,在进水流量为0．8m^3／d、水力停留时间为1．5d时,该工艺对浊度、CODMn、UV254、TN和NH4^＋-N的平均去除率分别为93．71％、43．19％、17．69％、49．15％和48．92％。潜流人工湿地对原水预处理效率较高,运行稳定,可以有效减轻后续工艺的处理负荷。     

人工湿地系统预处理济南玉清湖水库的入库水

采用人工湿地在玉清湖水库进水口处对入库黄河水进行预处理，考察了潜流人工湿地和表流人工湿地的处理效果。结果表明，在进水流量为75L／h的条件下，潜流人工湿地与表流人工湿地均有较好的处理效果，对COD的平均去除率分别为49．17％和36．58％，出水COD基本在20mg／L以下；对TN的平均去除率分别为52、14％和43．68％，出水TN基本在3mg／L以下；对TP的平均去除率分别为48．07％和39．69％，出水TP基本在0．08mg／L以下。     

The microbial diversity of laboratory-scale wetlands appears to be randomly assembled

This study investigated the formation of the microbial communities in two horizontal subsurface-flow laboratory-scale constructed wetlands, one planted and the other one unplanted. The abundance of the predominant functional groups (Archaea, Bacteria and sulphate-reducing bacteria) was determined using fluorescence in situ hybridization and the diversity and community structure of those functional groups were analysed using denaturing gradient gel electrophoresis. The numbers of Archaea, Bacteria and sulphate-reducing bacteria were indistinguishable in both reactors (P=0.99, 0.80 and 0.55, respectively). The microbial communities in both wetlands were typically no more similar than if they had been randomly assembled from a common source community. Plants did not appear to exert a strong effect on the structure of the microbial communities in the horizontal subsurface-flow constructed wetlands (HSCWs) studied in this investigation.     

The use of Bassia indica for salt phytoremediation in constructed wetlands

The treatment and reuse of wastewater in constructed wetlands offers a low-cost, environmentally-friendly alternative for common engineered systems. Salinity in treated wastewater is often increased, especially in arid and semi-arid areas, and may harm crops irrigated from wetlands. We have strong evidence that halophyte plants are able to reduce the salinity of wastewater by accumulating salts in their tissues. Bassia indica is an annual halophyte with unique adaptations for salt tolerance. We performed three experiments to evaluate the capability of B. indica for salt phytoremediation as follows: a hydroponic system with mixed salt solutions, a recirculated vertical flow constructed wetland (RVFCW) with domestic wastewater, and a vertical flow constructed wetland (VFCW) for treating goat farm effluents. B. Indica plants developed successfully in all three systems and reduced the effluent salinity by 20-60% in comparison with unplanted systems or systems planted with other wetland plants. Salinity reduction was attributed to the accumulation of salts, mainly Na and K, in the leaves. Our experiments were carried out on an operative scale, suggesting a novel treatment for green desalination in constructed wetlands by salt phytoremediation in desert regions and other ecosystems.     

The effect of primary treatment and flow regime on clogging development in horizontal subsurface flow constructed wetlands: An experimental evaluation

The effect of both the type of primary treatment (hydrolitic up-flow sludge blanket (HUSB) reactor and conventional settling) and the flow regime (batch and continuous) on clogging development in subsurface flow constructed wetlands (SSF CWs) was studied. Clogging indicators (such as accumulated solids, hydraulic conductivity and drainable porosity) were determined in an experimental plant with three treatment lines. Correlations were encountered between the solids accumulated and both saturated hydraulic conductivity and drainable porosity reduction over time (74.5% and 89.2% of correlation, respectively). SSF CW implemented with a HUSB reactor accumulated ca. 30% lower sludge (1.9 kg DM/m²) than a system with a settler (2.5-2.8 kg DM/m²). However, no significant differences were recorded among treatment lines concerning hydraulic parameters (such as hydraulic conductivity or porosity). Root system development contributed to clogging. Accordingly, planted wetlands showed between 30% and 40% and 10% lower hydraulic conductivity and porosity reduction, respectively, than non-planted wetlands.     

往复流人工湿地处理城市污水的效能研究

使污水周期性地往复流过水平潜流湿地而构成往复流人工湿地,以提高人工湿地处理污水的效能.对两块大小、填料、植物都完全相同的往复流湿地和单向流湿地进行了历时为8个月的对比试验,结果表明：在同等运行条件下,两种人工湿地对COD、SS的去除率大致相当,分别为76.3%和97.1%;往复流人工湿地对TP、TN、NH3-N等指标的去除效果明显优于单向流湿地,其对TP、TN、NH3-N的去除率分别为76.3%、41.7%、35.6%,而单向流湿地的只有65.2%、27.6%、16.9%.     

水平潜流人工湿地在工业废水处理中的应用

水平潜流人工湿地作为一种非常有效的污水处理工艺,应用于工业废水的处理已经30多年。综述了近年来国内外水平潜流人工湿地在石油化工、食品、酿酒、造纸、制革、纺织,钢铁和制药等工业废水处理系统中的应用,指出了水平潜流人工湿地的应用前景和研究方向。     

Microbiological investigations for sanitary assessment of wastewater treated in constructed wetlands

Microbiological investigations into the occurrence and fate of pathogens in wastewater were carried out in a multi-annual measurement programme, using samples from three artificial wetlands equipped with pre-treatment systems (multi-chamber septic tanks, lagoons) and predominantly treating domestic wastewater. In this study, the concentrations of indicator organisms and pathogenic or potentially pathogenic microorganisms were determined in the various components or stages of the systems. The evaluation of data from some 3.600 microbiological analyses and a comparison with older data from a plant which has already been operation for 18 y made it possible for the first time ever to include operational factors in the assessment. Average removal of all major indicator organisms and pathogens is 1.5-2.5 log units for one-stage systems and increases to 3-5 log units for multi-stage systems. Significant differences between horizontal and vertical filters were not found. If no clogging problems arise during their operation, multi-stage systems can meet the requirements of the EU bathing water and irrigation water directives. Influent concentration, wastewater temperature, and hydraulic loading rate were found to be major factors of influence. The performance of constructed wetlands in removing microorganisms is clearly superior to that of conventional biological activated sludge systems.     

城市污水生物—生态处理工艺的能效分析

采用生物—生态组合工艺处理城市污水,其中生物单元采用连续流一体化生物反应器(CIBR),生态单元采用波形潜流人工湿地。根据原水水质和生态单元处理效能的季节性变化,通过调整CIBR生物单元的运行工况,实现了对城市污水的高效、低耗、稳定、达标处理。该系统的出水水质全年可稳定地达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)的一级A标准,处理能耗平均为0.362(kW.h)/m3,在达到相同处理效果的基础上,比A2/O工艺和Bardenpho工艺分别降低了37.69%和57.91%。该组合工艺的节能原理是建立在生物单元变工况运行与生态单元低能耗脱氮除磷共同作用基础上的。