Performance of a Horizontal Flow Constructed Reed Bed Filter for Municipal Wastewater Treatment: The Case Study of the Prototype Installed at Gaston Berger University, Saint-Louis, Senegal

In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.

A Lab-scale Study on the Routes of Nitrogen and Phosphorus Removal in Gravel-based Reed Bed Systems

The removal of ammonia and phosphorus from an artificial wastewater was studied in two lab-scale reed beds.During batch and continuous operations,it was found that ammonia was removed from the wastewater via a two-step process,sorption inside bed matrices followed by nitrification into nitrite and nitrate.Rapid decrease in the concentration of ammonia in the artificial wastewater was observed during the batch operation,whereas during the continuous operation,which lasted for 39 days,the percentage removal of ammonia decreased gradually with time before stabilizing at around 20%.The efficiency of phosphorus removal exhausted rapidly during the continuous operation,from 39% on the first day of operation to virtually zero after only 5 days.The results suggest that sorption(which may include ion exchange,adsorption,and biomass assimilation) serves as an initial step to remove ammonia and phosphorus from the wastewater,prior to any microbial transformations.

The Design of Treatment Wetlands in the United Kingdom:Successes,Failures,and Alternative Approaches

Constructed wetland was first introduced into the United Kingdom in the middle of 1980s,following a visit by a group of scientist to Western Germany.In the past 2 decades,the applications of constructed wetlands in this country have expanded substantially,due to the demand for green technologies and rising cost of fossil fuel energies.This paper reported a statistical investigation of the performances of 78 horizontal flow wetlands,representatives of such system in the United Kingdom.Alternative design equations,based on organic matter removal efficiency,have been developed from Monod kinetics,and the accuracy and reliability of current and alternative design approaches have been examined.

Kinetic Modelling of the Removal of Seven Common Pollutants in Subsurface Flow Constructed Wetlands

The main removal mechanisms for the degradations of seven pollutants in wastewater treatment wetlands were analysed,and a mathematical model was established to quantify the removal of each pollutant,based on its main removal mechanisms.Subsurface horizontal flow wetlands were treated as a series of continuous stirred-tank reactors(CSTRs).Kinetic models for the removal of biochemical oxygen demand,chemical oxygen demand,ammonia,total nitrogen and faecal coliforms were established by combining Monod or first-order kinetics with CSTR assumptions.These tentative models account for a wide range of factors that affect wetland performance,but the models have not been proven by experiment data.Depending on the derivation of various coefficients in the models and verification by actual performance data,this study may provide a starting point for an integrated pollutant removal model to be developed,and experimentally verified,thereby making a step forward from the current greenbox'approach of wetland design.

模块化移动床人工湿地脱氮效果及N_(2)O排放研究

模块化移动床人工湿地(Modular Moving Bed Constructed Wetland,MMB-CW)因其去除效率高和抗堵塞等优势逐渐成为研究热点。本研究构建了轻质陶粒填充的MMB-CW,研究了不同填充度条件下MMB-CW的脱氮效果与N_(2)O的排放特征。结果表明:陶粒填充的MMB-CW具有良好的NH_(4)^(+)-N和NO_(3)^(-)-N去除效果,脱氮效果随陶粒填充度升高而增强(P<0.05)。在MMB-CW系统启动运行过程中,高陶粒填充度有利于促进硝化-反硝化耦合脱氮。当MMB-CW系统稳定时,100%填充度NH_(4)^(+)-N和NO_(3)^(-)-N的去除率分别为21.8%和43.7%,N_(2)O排放通量为0.6 mg/(m^(2)·d),与现有研究人工湿地N_(2)O排放通量相比处于较低水平。该研究为扩大MMB-CW技术的实际应用提供了一定的理论依据。

小流域富营养化水体修复研究——以海马齿联合多种基质的人工湿地为例

流域水体富营养化已成为水环境的重要问题。构建基于多类型基质与浮床植物组合的水平潜流人工湿地,考察其对小流域富营养化水体的生态修复性能,并通过高通量测序等方法解析该湿地系统微生物群落变化特征。研究结果表明,以基质和浮床植物组合的复合生态系统可在更短时间完成启动,对小流域富营养化水体中的总氮(Total Nitrogen,TN)、总磷(Total Phosphorus,TP)和氨氮(NH_(3)-N)表现出较强的去除效果;多组合基质投至水底,与底泥接触,其凭借吸附及截留作用,在短时间内能有效净化水中的氮磷;水平潜流人工湿地中,海马齿浮床根际为水体微生物的固定提供良好场所,使微生物多样性增加,能加速有机污染物的降解,改善水质。

人工湿地净化富营养化河水试验研究(二)——基质层及流态对氮素污染物净化效果的影响

通过中试试验研究了基质层及流态对人工湿地净化富营养化河水中氮素污染物的影响情况,结果表明:砾石基质层厚度从80cm增加到120cm对湿地池净化氮素污染物的效果没有明显影响;将上层砾石替换为沸石后,湿地池对NH3-N的净化效果明显提高,说明不同的基质材料对NH4+具有良好的选择性吸附作用,而将上层砾石替换为炉渣后湿地池对氮素污染物的净化效果几乎没有变化;在4种湿地流态中,复合流态(垂直流+潜流)湿地池对TN、NH3-N、NO3-N的去除率均为最高,且与潜流-垂直流相前后次序没有显著相关性;潜流、垂直流湿地池对氮素污染物的去除率介于复合流、表面流之间;表面流最低。

植物吸收对模拟污水净化系统去除氮、磷贡献的研究

采用炉渣、沸石和土壤为基质,黑麦草(Lolium mutliflorum)、水芹(Oenanthe javanica)和香根草(Vetiveria Zizanioides)为植被模拟了不同基质人工湿地和无基质的浮床植物净化系统,研究了3种植物在4种净化系统内对生活污水N、P的吸收和去除作用。结果表明:3种植物在各净化系统中均能正常生长,总生物量干重在121.8～557.4g/m^2之间,均以黑麦草最高。4种净化系统中,黑麦草、水芹和香根草的地上部N、P平均含量分别为26.33、3.33 mg/g,24.08、2.64 mg/g和12.39、1.41 mg/g:地下部N、P平均含量分别为8.92、1.52 mg/g,19.39、2.55 mg/g和10.85、1.33 mg/g。浮床系统因承受的N、P负荷较高且不存在基质,3种植物的地上部、地下部N、P平均含量几乎均高于各基质人工湿地。4种净化系统中,黑麦草对N、P的吸收能力均明显高于水芹和香根草,3种植物的N、P总吸收量分别为:(黑麦草)5.26～11.73、0.72～1.31g/m^2,(水芹)1.88～8.08、0.18～1.83g/m^2,(香根草)0.86～2.44、0.07～0.79g/m^2,各植物的N、P吸收量均以浮床系统最高。植物对N、P的吸收量主要取决于自身的生物量和N、P含量。黑麦草吸收的N、P量分别占4种净化系统N、P去除总量的39.3%～59.4%和88.9%～96.3%,其对N、P的吸收己成为各净化系统去除N、P的主要机制。水芹和香根草对N的吸收仅是各净化系统去N的一个途径,其贡献率分别为:10.2%～37.6%和4.8%～17.7%;水芹和香根草对P的吸收量占浮床系统去P总量的96.4%和83.2%,是系统除P的主要机制,但其对3种基质湿地的去P贡献则很小。

人工湿地植物的选择及湿地植物对污染河水的净化能力

阐述了在人工湿地中植物的作用和选择人工湿地植物的原则,分析比较了4种常用于人工湿地的植物的生长特性、环境适应性,并进行了潜流人工湿地和生物滤床(作为人工湿地的对照试验)对污染河水处理效果的比较。结果表明,在湿地床中,美人蕉(C.flaccida)和香根草(Vetiveria zizanioides)长速较快,较适合于需快速启动的湿地系统;风车草(Cyperus slternifolius)长势良好,覆盖度接近100%;纸莎草(Cyperus papyrus)长势较差,环境适应性差。在HRT为13 h的运行条件下,系统稳定运行后植物对CODMn、TP、TN、NH+4-N的平均去除率分别为3.1%、2.0%、12.7%、5.2%,植物对浊度没有明显的改善作用。人工湿地有较强的耐冲击负荷能力,在HRT为13h条件下系统的处理能力还有较大的提升空间。

人工模拟污水净化系统去除生活污水氮、磷效果的比较研究

在温室内，分别以炉渣、沸石和土壤为湿地基质，水芹（Oenanthe javanica）、黑麦草（Lolium mut1iflorum）和香根草（Vetiveria zizanioides）为植被构建了模拟人工湿地和无基质的浮床植物系统处理生活污水，比较研究了不同污水净化系统去除氮、磷的效果。结果表明，在较低氮、磷负荷和水力停留时间为6d的条件下，炉渣、沸石和土壤基质人工湿地系统对生活污水中的全氮（TN）、NH4^＋ -N和全磷（TP）均表现出很好的净化效果，平均去除率均在91．0％以上；对NO3^- -N的去除率较低，为58．0％～85．5％。浮床系统因承受较高的负荷，对TN、NH4^＋ -N、NO3^- -N和TP的去除率均明显低于各基质湿地。而从污染负荷的去除率来看，土壤基质湿地对TN、NH4^＋．N、NO3^＋ -N和TP的负荷去除率低于炉渣和沸石基质湿地；浮床各系统NO3^- -N负荷去除率的负增加使TN的负荷去除率降低，但其NH4^＋ -N的负荷去除率均高于各湿地系统；浮床水芹和黑麦草系统的TP负荷去除率也高于各湿地系统。植物种类不同，其吸收N、P的能力存在很大差异。以黑麦草为植被的人工湿地和浮床系统，植物的吸收作用是各系统去氮除磷的主要机制；水芹和香根草吸收的氮、磷总量在人工湿地中远小于黑麦草，其吸收作用仅是各湿地系统去除氮、磷的一个途径；而水芹和香根草对磷的吸收则是浮床系统除磷的主要机制。

新型生物滤床-人工湿地耦合系统强化处理生活污水研究

通过构建基于自通风管网的生物滤床和潜流式人工湿地中试耦合系统,对比了混合过滤石材的原有系统a和采用不同填料的对比系统b的污染物去除效果。结果表明,系统b对COD、NH4+-N、TN和TP的去除率分别为74.10%、94.14%、73.57%和69.53%,优于系统a;填料的优化配置对中试耦合系统污染物去除效率的提升效果显著,系统b对上述指标的去除较原有系统a分别提升了11.00个、11.55个、2.69个和8.09个百分点;生物滤床单元对NH4+-N的去除占主要作用,而潜流式人工湿地单元则对去除COD、TN和TP的贡献较高。温度升高,COD去除率总体呈下降趋势,NH4+-N的去除率呈上升趋势,对TN、TP的去除效果影响不明显。

氧化塘-人工湿地塘床系统处理造纸废水应用研究

在介绍江苏双灯纸业集团公司利用人工湿地塘床系统处理废水的工艺过程和运行情况的同时,分析了该系统净化污染物的机理及生态环境效益.分析结果表明,人工湿地塘床系统不仅对特征污染物指标CODCr,BOD5和SS等具有较高的去除率,还通过出水灌溉芦苇降低了土壤盐渍化程度,并且湿地中生长的芦苇可作为造纸原材料回收利用,同时人工湿地形成了独特的生态环境,既改善了局部景观,又保护了野生环境.

人工湿地塘床系统净化地表水的试验研究

成都市活水公园人工湿地塘床系统对枯水期府河水中的CODCr,BOD5,TN ,TP ,oil,LAS ,Ar -OH ,NH3,S2 - 等污染物的去除率在 85%以上 ,总大肠菌群的去除率达 99 9%以上 ,其净化效果能够满足净化地表水或污水深度处理的需要。由此可见 ,人工湿地塘床系统是一种生态滤池。

钢渣填料-潜流湿地秋冬季运行维护效果研究

选用钢渣、砾石等填料及水生植物构建两座人工湿地进行对比试验,考察秋冬季潜流人工湿地系统采用芦苇保温法的运行效果,结果发现其出水效果好于无保温床体,保温床体对COD、TN、TP的去除率分别为20.74%、19.36%、42%。为了应对由于温度的降低导致反硝化细菌活性受到抑制的情况,采用强化反硝化的方法向湿地中投加适宜碳氮比的甲醇,结果表明:当碳氮比为1.85时,出水TN平均质量浓度为13.66 mg/L,达到了《城市污水再生利用景观环境用水水质》(GB/T 18921-2002)标准(TN≤15 mg/L)。

人工湿地在制革废水处理中的应用

人工湿地主要利用基质、植物、微生物的物理、化学、生物三重协同作用,对污水进行处理的一种独特的废水处理新技术。本文综述了人工湿地在制革废水处理中的研究和应用情况,分析了该系统存在的问题,并提出了解决方法,展望了人工湿地在制革废水处理中的应用前景。

生态浮床与人工湿地净水效果比较小试研究

生态浮床和人工湿地都是近年来在国内外采用的用于净化水质的生态修复的方法,该文章主要研究了静态条件以及不同水力负荷下,种植黄菖蒲的生态浮床与人工湿地的净水效果。试验期间进水高锰酸盐指数、TN、TP、NH4+-N平均质量浓度分别为4.74 mg/L、2.92mg/L、0.26 mg/L、1.77 mg/L。结果表明,在静态条件下黄菖蒲生态浮床对污染水体具有较好的去除效果,去除率分别为高锰酸盐指数:37.6%、TN:89.9%、TP:65.5%,对于NH4+-N的处理效果相同条件下人工湿地则优于生态浮床,去除率为92.4%。3种水力负荷0.035 m3/(m2.d)、0.06 m3/(m2.d)、0.12 m3/(m2.d)相比较,0.035 m3/(m2.d)水力负荷下,生态浮床对TP、NH4+-N、TN、高锰酸盐指数的去除率较好,分别为87.4%、66.8%、77.1%、21.16%。人工湿地则没有明显的变化趋势。通过对生态浮床和人工湿地这两种方法的净化水质的效果进行对比分析,以期在净化河道湖泊水体方面得到很好的应用。

碳纤维湿地式浮床对微污染水体的净化研究

首先研究了千屈菜(Lythrum salicaria Linn)、小香蒲(Typha minima Funk)以及黄菖蒲(Iris pseudacorus)3种较适合北方种植的耐寒植物在微污染水中的生长状况及对污水的净化效果,其次研究了碳纤维湿地式生态浮床系统对微污染水体中各指标的净化效果。结果表明,综合分析生长状况及对污水的净化效果,最适合用于浮床的植物依次是千屈菜、小香蒲、黄菖蒲。在水力停留时间1 d及气水比为2∶1的条件下,种植了千屈菜的碳纤维湿地式生态浮床对污水中的浊度、COD、NH4+-N以及TP都有很好的去除效果,平均去除率分别为96.47%、83.76%、90.48%及81.58%以上。但浮床系统对微污染水体中的TN去除效果不佳,平均去除率仅为15.80%。

复合生态床的植物配置与净化效能研究

复合生态床是由填料和植物按一定需要组合而成的梯级人工湿地系统,是一种新型的生活污水生态处理工艺。结合山地城镇的地形特点构建了三级人工湿地生态床,并开展了处理生活污水的中试(13.5 m3/d)研究。选择美人蕉、风车草、菖蒲、香蒲四种土著植物以及陶粒、钢渣、石灰石等3种填料,通过进行不同的组合,考察其对除污效果的影响。结果表明:美人蕉的生物量最大,对氮、磷的去除能力较强;最优植物组合为风车草—美人蕉—菖蒲,其对NH3-N、TN和TP的去除率分别为69.85%、59.31%和75.04%。

艾比湖近期出现大面积干涸

The Ebinur Lake and its peripheral regions are the important wetlands in Xinjiang. However, its lake bed is recently dried up in large area. Analyzing from the data monitored by EOSVMODIS satellite, the water area of the Ebinur Lake has been sharply reduced since summer 2006, its lake bed has been dried up in large area since late-July, and such situation became more serious up to mid-August. According to the data monitored by EOS\MODIS satellite, the water area of the lake was 550.6 km2 on August 19, 2006, and it was reduced by 263.4 km2, 126.4 km2 and 158.4 km2 comparing with that in late-July and early-August 2006 and mid-August 2005, respectively.According to the data monitored by EOS\MODIS satellite, the water area of the Ebinur Lake fluctuated in a range of 700-1 000 km2 during the period from April 2002 to July 2006, and it was larger than 1000km2 during the period from the end of spring to early summer 2005 (Tab.1). However, the water area of the Ebinur Lake was reduced to 550.6 km2 in mid-August 2006, the lake bed was dried up in large area, and the water area was the smallest since recent 4 years.

利用不同物候期水生植物配置提高浮床人工湿地的除氮效果

为验证利用不同物候期水生植物配置提高碳氮比失衡湿地脱氮能力的可行性,设计了向水芹菜(Oenanthe javanica)浮床人工湿地系统中添加轮叶黑藻(Hydrilla verticillata)的实验,研究了在秋、冬季低温条件下,暖季型植物分解释碳对系统氮去除效果的影响.结果表明,添加轮叶黑藻显著提高了系统水体碳氮比,促进反硝化作用,提高总氮和硝态氮的去除率.在4个周期中,与对照组相比,物候期组合型浮床人工湿地系统的总氮去除率分别提升23.03%、10.90%、18.55%和22.93%,硝态氮去除率分别提升38.28%、20.74%、17.87%和17.06%.由此可见,利用暖季型和冷季型植物配置提高碳氮比失衡湿地氮去除率是可行的.