不同C／N下人工湿地的脱氮效果及其强化措施

以人工湿地为研究对象，分析了不同C／N下人工湿地的脱氮效果。结果表明，C／N为10时，TN、NO2-N和COD平均去除率分别为（75．36±10．55）％、（86．34±9．23）％和（67．60±4．10）％，都显著高于其他2组系统（P=0．006、0．001、0〈0．01）；随着C／N的增加，NO3-N去除率呈现出上升的趋势；NH4-N刚好相反，C／N为1时，明显要高于其他2种情况（P=0〈0．05），平均去除率为（65．42-1-14．31）％。针对C／N为1时人工湿地脱氮效率较低（51．294-14．48）％的情况，对系统进水采取了添加一定量好氧反硝化细菌固定化小球并曝气12h的强化实验措施。结果发现，强化实验条件下TN、NOr-N和N03-N去除率均提高了10％以上，且都要明显高于非强化实验条件（P：0．003、0、0〈0．01），同时NH4-N和COD去除率没有明显差异，研究结果表明，从微生物角度对系统进水进行前处理有助于提高人工湿地脱氮效率。     

人工湿地中基质与植物对污染物去除效率的影响

针对太湖五里湖富营养化水体，采用中试规模的人工湿地现场实验开展了不同基质、不同植物的污染物去除效果研究。基质采用炉渣和沸石2种，在一个湿地池种植单一植物茭白，另一个湿地池种植鸢尾＋菖蒲混合植物，同时构建了无植物的对照组湿地。研究表明：（1）在运行初期，沸石和炉渣2种基质对TN、TP的去除率差异为12.5%和12.6%，吸附饱和后，2种基质对TN和TP的去除率差异缩小为3.2%和6.1%，从长期运行来看，炉渣和沸石2种基质在人工湿地中的去除效率差异将减小；（2）茭白单一植物湿地对污染物的去除率与鸢尾＋菖蒲混合植物湿地对污染物的去除率两者之间差异不大；（3）人工湿地种植植物后对TN、TP的去除率比无植物状态时分别高出13.6%和19.5%，植物在人工湿地中对污染物的去除发挥了重要作用；（4）在本试验条件下，茭白吸收所去除的氮数量为湿地氮总去除量的8.95%，茭白吸收去除磷的数量为湿地磷总去除量的20.16%，在人工湿地中，茭白吸收对磷的去除效率比对氮的去除效率高。     

3种不同基质潜流湿地对磷的去除效果

基质是潜流式人工湿地污水处理系统的重要组成部分，直接影响到系统的处理效果。本文研究了由沸石、页岩陶粒和碎石3种不同基质构建的潜流式人工湿地对磷的去除效果。结果表明，在设计水力停留时间3d，连续进出水情况下，碎石单元对磷的去除效果最好，页岩陶粒单元次之，沸石单元效果最差，平均去除率分别为95％、60％和35％。在潜流式人工湿地污水处理系统运行初期观察到磷释放现象，沸石单元最为明显。进水磷浓度较低时，磷的去除率随浓度升高而升高，当正磷、总磷浓度分别升高到2．4—2．5和3．1～3．3mg／L时，正磷、总磷的去除率开始迅速下降。     

不同曝气参数下间歇增氧垂直流人工湿地脱氮的分层效应

以新型间歇增氧垂直流人工湿地(IA-VFCW)为研究对象,揭示了不同工况对人工湿地污染物去除的分层效应及去除效果的影响.结果 表明:不同曝气参数对细砾石层、煤渣层污染物去除的影响较小;对曝气区、湿地植物区污染物去除的影响较大.当进水NH4-N质量浓度为25 mg·L-1、COD为200 mg·L-1时,细砾石层、煤渣层对NH4+-N和TN平均去除率分别为10.8％、9.3％和13.3％、11.6％,两区域中均无NO2-N、NO3-N的积累;细砾石层对COD去除的贡献较大,COD平均去除率为67.2％.曝气区对NH4-N、TN去除贡献较大,NH4-N、TN的最大去除率分别达到69.3％、40.9％,COD平均去除率为25.4％.在低曝停比下,曝气量的增加将提高IA-VFCW对TN的去除性能;在高曝停比下,曝气量的增加会降低IA-VFCW对TN的去除效果,且会造成NO--N积累.在曝气量2 m3·h-1、曝停比1/3、曝停周期6h工况下IA-VFCW具有较好的污染物去除效果,NH4+-N去除率为94.9％、TN去除率为77.0％、COD去除率为90.0％.IA-VFCW脱氮性能明显优于传统垂直流人工湿地.     

电化学法去除水中的硝酸根

以钛基氧化物涂层材料（Ti／SnO2-Sb2O5-IrO2）为阳极，碳纳米管修饰的石墨（GE—CNT）为阴极构建电化学系统进行硝酸根（NO3-）去除研究，考察了阴极材料、阴极电位和pH值对电化学法去除水中NO[的影响，同时检测了铵离子（NH4＋）和亚硝酸根（NO2-）的生成量。结果表明，利用碳纳米管修饰的石墨阴极可获得较好的硝态氮去除效果；随着阴极电位负移，NO3-去除率随之升高；酸性条件下NO3-去除率最高，NH；生成量也更多。对于由NO3-转化产生的NH4＋，在氯离子存在条件下再次进行电化学处理120min，其去除率可达97．1％。     

改良型A2／O-MBR工艺的反硝化除磷性能研究

重点考察了-种改良型膜生物反应器（A2／O—MBR）的脱氮除磷性能。该工艺主要特点在于对膜池硝化回流液进行了固液分离，并将上清液和浓缩污泥分别回流至缺氧池和厌氧池，这种改进提高了系统对氮、磷的同步去除效率。实验结果表明，在水力停留时间（HRT）为12h，污泥龄（SRT）为30d，混合液回流比为200％的运行条件下，进水COD、NH4＋-N、TN和TP平均浓度分别为（225±38）、（24．8±3．9）、（26．7±2．9）和（2．90±0．53）mg／L时，增加膜池硝化回流液固液分离装置前后，系统对COD和NH4＋-N的去除都维持在较高水平，而系统对TN和TP的去除效果显著提高，出水TN和TP平均浓度分别由（14．9±3．3）mg／L和（1．95±0．72）mg／L下降到（9．4±1．9）mg／L和（0．91±0．38）mg／L，表明增加膜池硝化回流液固液分离装置显著改善了A2／O-MBR系统的脱氮除磷效果。反硝化除磷活性实验结果进一步表明，改进后系统中反硝化除磷活性占总除磷活性的比例由51．5％上升至61．7％，说明增加膜池硝化回流液固液分离装置强化了系统的反硝化除磷性能。     

不同基质复合垂直流人工湿地对富营养化景观水的净化效果

研究了两套不同基质复合垂直流人工湿地小试装置在不同季节对富营养化景观水的净化效果,分析了温度变化对污染物去除效果的影响,考察了微生物的硝化强度和反硝化强度以及基质理化性质对植物生长状况的影响,并探讨了氮、磷的去除途径.结果表明:不同基质复合垂直流人工湿地随季节变化对浊度、COD和磷的去除效果差异不明显;温度降低对脱氮效果影响显著,对磷的去除影响不大.沸石-页岩湿地硝化强度和反硝化强度优于砾石湿地.采用沸石作为基质可以提高系统对氮的去除效率,促进湿地植物的生长.对氮、磷去除途径的分析表明:微生物的硝化反硝化作用以及基质对磷的吸附沉淀作用是复合垂直流人工湿地去除氮、磷的主要途径;植物吸收分别占湿地TN、TP去除量的16%和35%左右,也是个重要途径.     

表流-水平流复合人工湿地对高污染河水的净化

为了研究表流-水平流复合人工湿地对高污染河水的净化效果及植物对复合湿地中二级潜流湿地的影响作用,实验构建了表流+芦苇水平潜流和表流+无植物水平潜流复合人工湿地。在相同的水力负荷下连续运行一年的结果表明,复合人工湿地对高污染河水中TN、NH3-N、TP、COD、BOD5和SS的去除率分别为57.3%~63.1%、65.7%~68.1%、69.4%~82.7%、85.3%~86.3%、96.7%~96.9%和97.9%~98.2%,种有植物的二级潜流湿地具有更好的脱氮和除磷效果;表流湿地作为复合湿地的第一级能够有效去除大部分的有机污染物和悬浮物,进而避免二级潜流湿地的堵塞,并利于二级潜流湿地的脱氮除磷的进行;复合湿地对有机物和悬浮物的去除不受季节性波动的影响,但是其脱氮效果受季节波动的影响较大。     

土壤渗滤介质系统去除雨水径流污染物

利用昆明当地的土壤在室内填装一个土柱渗滤系统，使用配水浓度模拟昆明市区雨水径流污染物浓度，进行去除雨水径流污染物的实验研究，考察系统对COD、TN、NH4＋、NO3^-、NO2^-和TP的去除效果。实验结果表明，该土壤渗滤系统对COD平均去除率为82．04％，对TN的平均去除率为22．64％，对NH；平均去除率为94．26％，但是对NO3^-、NO2^-去除效果较差，对TP平均去除率为96．95％；另外，系统长期运行导致下渗速度降低，出水效果反而变好。     

复合人工湿地对水源地库区水质净化效果分析

宁波皎口水库是水源地，皎口复合人工湿地位于皎口水库的进水口，采用多种水流方式复合，对提高水库水质及保障饮用水安全具有积极的作用。为了探明人工湿地在微污染地区的应用价值，对人工湿地水源地水质净化效能进行了研究。在1年的监测调查调查中，研究探讨了复合人工湿地及其不同模块在不同季节的净化效果。结果表明，该人工湿地对总氮和总磷的平均去除率分别可达到为34.7%和42.6%，对COD和TOC的平均去除率可达到28.5%和21.6%。COD、NH₄⁺-N和总磷出水平均浓度分别为2.193、0.215和0.021 mg/L，均达到 《地表水环境质量标准》（GB3838-2002）Ⅱ类水质标准。在比较不同模块去除效果方面，提出了具有填料的生态滤池更有利于磷的去除，而对于氮、有机物等营养元素，复合多级强化生物膜系统及营养盐集约式植物资源化系统则有较好的去除效果。     

复合型人工湿地脱氮效能及其水力负荷影响规律

复合型人工湿地越来越多地被应用在面源污染管理中。不同类型的人工湿地对氮素的去除机理和去除性能是不同的。氮素在湿地生态系统中的去除受多种因素的影响和制约,不同的研究中氮素的去除效率变化较大。通过对韩国西部一复合型人工湿地中氮素的去除能力研究,分析了氮素的去除效率以及水力负荷对去除性能的影响,进而分析了人工湿地去除氮素的主要机理。结果表明,氨氮（NH＋4-N）、硝酸盐氮（NO-3-N）、凯式氮（TKN）和总氮（TN）的平均去除效率分别为13%、29%、35.3和26%。其中有机氮的去除是该复合型人工湿地中氮素去除的主要原因。水力负荷和先行干期天数对氮素的去除能力有一定影响。较长的先行干期天数和较低水力负荷可以提高氮素的去除效率。     

Evaluation of the giant reed (Arundo donax) in horizontal subsurface flow wetlands for the treatment of dairy processing factory wastewater

Two emergent macrophytes, Arundo donax and Phragmites australis, were established in experimental horizontal subsurface flow (HSSF), gravel-based constructed wetlands (CWs) and challenged by treated dairy processing factory wastewater with a median electrical conductivity of 8.9 mS cm(-1). The hydraulic loading rate was tested at 3.75 cm day(-1). In general, the plants grew well during the 7-month study period, with no obvious signs of salt stress. The major water quality parameters monitored (biological oxygen demand (BOD), suspended solids (SS) and total nitrogen (TN) but not total phosphorus) were generally improved after the effluent had passed through the CWs. There was no significance different in removal efficiencies between the planted beds and unplanted gravel beds (p?>?0.007), nor was there any significant difference in removal efficiencies between the A. donax and P. australis beds for most parameters. BOD, SS and TN removal in the A. donax and P. australis CWs was 69, 95 and 26 % and 62, 97 and 26 %, respectively. Bacterial removal was observed but only to levels that would allow reuse of the effluent for use on non-food crops under Victorian state regulations. As expected, the A. donax CWs produced considerably more biomass (37?±?7.2 kg wet weight) than the P. australis CWs (11?±?1.4 kg wet weight). This standing crop equates to approximately 179 and 68 tonnes ha(-1) year(-1) biomass (dry weight) for A. donax and P. australis, respectively (assuming a 250-day growing season and single-cut harvest). The performance similarity of the A. donax and P. australis planted CWs indicates that either may be used in HSSF wetlands treating dairy factory wastewater, although the planting of A. donax provides additional opportunities for secondary income streams through utilisation of the biomass produced.     

菖蒲和空心菜在处理微污染河水潜流人工湿地中的应用

为了探讨修复微污染河水的潜流湿地中植物对污染物去除效果的影响及其生长变化,在野外条件下构建2座分别栽种菖蒲和空心菜的水平潜流人工湿地,并以未栽种植物的湿地作空白。分析了湿地中污染物的去除效果,考察了湿地中植物的生物量、根系活力和氮磷含量的变化。植物湿地中污染物净化效果优于空白湿地,菖蒲和空心菜湿地对氨氮(NH+4-N)、总氮(TN)、总磷(TP)和高锰酸盐指数(CODMn)的平均去除率分别为61.1%和57.5%,31.5%和39.7%,24.7%和25.5%,20.4%和20.7%。实验结果表明,湿地中菖蒲的根系鲜重是空心菜的4.2倍,但其根系活力低于空心菜。2种植物均可在湿地中正常生长,但受湿地中营养盐浓度的限制性影响,移栽后的植物组织氮磷含量与移栽前相比下降了11.8%~20.3%。植物在净化微污染河水的潜流人工湿地中对N、P的去除起重要作用。     

潮汐流-潜流组合人工湿地污水净化效率

构建了潮汐流-潜流组合和潜流-潮汐流组合人工湿地对污水进行处理，分别研究2种组合人工湿地对污水的净化效果。结果表明，在平均进水COD浓度为214．28mg／L、NH4＋-N浓度为10．57mg／L、PO34--P浓度为5．44mg／L、TN浓度为10．25mg／L，水力负荷为o．2m3／（m2·d）的条件下，潮汐流-潜流组合人工湿地对COD、PO34--P的去除率分别为58．28％和46．99％，与潜流-潮汐流组合人工湿地处理效果相近；对NH4＋-N、TN，潮汐流-潜流组合人工湿地的去除率分别为69．93％和71．03％，比潜流-潮汐流组合人工湿地分别高15％和33％。潮汐流-潜流人工湿地的组合，在系统内实现了硝化-反硝化的组合，强化了系统对TN的净化效果，其对TN的净化效果比-般的潜流和表面流人工湿地组合提高20％～30％。总体上，潮汐流-潜流组合人工湿地具有更好的净化效果。     

Purification of water contaminated with Hg using horizontal subsurface constructed wetlands

As a global pollutant, Hg (Hg) since the turn of the last century has received increased attention. Decreasing the emission of Hg into the food chain and the atmosphere is an effective way to reduce the Hg damage. The current study provided information about pilot-scale horizontal subsurface flow (HSSF) constructed wetlands (CWs) to remove different Hg species in polluted water. Synthetic wastewater was fed to two HSSF CWs, one was planted with Acorus calamus L and the other was unplanted as a control. The total Hg (THg), dissolved Hg (DHg), and particulate Hg (PHg) from five sites along the HSSF CWs were analyzed to describe the process of Hg removal. Results show that the CWs have high removal efficiency of Hg which is more than 90%. The removal efficiencies of THg and DHg from the unplanted CW were 92.1?±?3.6% and 72.4?±?13.1%, respectively. While, the removal efficiencies of THg and DHg in planted CW were 95.9?±?7.5% and 94.9?±?4.9%, which were higher than that in blank CW. The PHg was mainly removed in the first quarter of the CWs, which was also revealed by the partition coefficient K_d. To a certain extent, the effect of plants depends on the hydraulic retention time (HRT). The results in the current study show the potential of the HSSF-CWs for restoration from Hg-contaminated water.

     

Temporal evolution in PPCP removal from urban wastewater by constructed wetlands of different configuration: a medium-term study

Pharmaceuticals and personal care products (PPCPs) are widely distributed in urban wastewaters and can be removed to some extent by constructed wetlands (CWs). The medium-term (3-5 years) behaviour of these systems regarding PPCP removal is still unknown. Seven mesocosm-scale (1 m²) CWs of different configurations were operated outdoors for 39 months under the same conditions to assess their PPCP removal ability and temporal evolution. CWs differed in some design parameters, namely plant presence, species chosen (Typha angustifolia vs Phragmites australis), flow configuration and presence/absence of gravel bed (floating macrophytes surface flow, FM-SF; free-water surface flow, FW-SF; free-water subsurface flow, FW-SSF; or conventional horizontal subsurface flow, SSF). PPCP efficiencies decreased throughout time and performance differences among CWs disappeared with the systems aging. This could be due to a homogenization process in the systems caused by detrimental factors like saturation, clogging and shading. Winter efficiencies were lower than summer ones for salicylic acid, caffeine, methyl dihydrojasmonate, galaxolide and tonalide, and seasonal biological activities seem key factors to explain this fact. Maximal removal efficiencies were achieved in an unplanted-FW-SSF for ketoprofen (47-81%), naproxen (58-81%) and salicylic acid (76-98%); in an unplanted-SSF for caffeine (65-99%); in a Phragmites-FM-SF for ibuprofen (49-96%) and diclofenac (16-68%); in a Typha-FM-SF for carbamazepine (35-71%); and in a Typha-FW-SSF for methyl dihydrojasmonate (71-96%), galaxolide (67-82%) and tonalide (55-74%). Photodegradation could be involved in ketoprofen, naproxen, ibuprofen and diclofenac removal. Carbamazepine and diclofenac were moderately removed by the most efficient CWs studied. Carbamazepine might be eliminated by vegetal uptake.     

植物对潜流人工湿地净化微污染水效果的影响研究

以4种湿地植物为实验对象,在野外构建中试潜流人工湿地,研究了不同植物及植物连根收割对湿地运行效果的影响。结果显示,植物明显提升了湿地的去污效果;其中美人蕉湿地的TP和NH4+-N去除率最高,达到55.6%和78%;空心菜湿地的TN去除率最高,达到80.5%;芦竹湿地的COD去除率最高,为26.6%;植物连根收割后,湿地运行效果下降;其中TN去除率降至空白水平之下,而其他污染指标下降至略高于空白的水平。     

Pharmaceutical removal in tropical subsurface flow constructed wetlands at varying hydraulic loading rates

Determining the fate of emerging organic contaminants in an aquatic ecosystem is important for developing constructed wetlands (CWs) treatment technology. Experiments were carried out in subsurface flow CWs in Singapore to evaluate the fate and transport of eight pharmaceutical compounds. The CW system included three parallel horizontal subsurface flow CWs and three parallel unplanted beds fed continuously with synthetic wastewater at different hydraulic retention times (HRTs). The findings of the tests at 2-6 d HRTs showed that the pharmaceuticals could be categorized as (i) efficiently removed compounds with removal higher than 85% (ketoprofen and salicylic acid); (ii) moderately removed compounds with removal efficiencies between 50% and 85% (naproxen, ibuprofen and caffeine); and (iii) poorly removed compounds with efficiency rate lower than 50% (carbamazepine, diclofenac, and clofibric acid). Except for carbamazepine and salicylic acid, removal efficiencies of the selected pharmaceuticals showed significant (p<0.05) enhancement in planted beds as compared to the unplanted beds. Removal of caffeine, ketoprofen and clofibric acid were found to follow first order decay kinetics with decay constants higher in the planted beds than the unplanted beds. Correlations between pharmaceutical removal efficiencies and log K(ow) were not significant (p>0.05), implying that their removal is not well related to the compound's hydrophobicity.     

出水口位置对垂直潜流人工湿地净化的影响

研究出水口位置对垂直潜流人工湿地净化的影响。垂直潜流人工湿地以间歇进水方式运行,进水水力负荷为0.125m3/(m2.d),进水来自南宁市琅东污水处理厂初沉池出水。研究结果表明,出水口位置对垂直潜流人工湿地净化有显著影响。与底部出水相比,中部出水的TN、SS和COD去除率分别提高了8.01%、8.48%、7.99%,出水NO-3-N质量浓度降低了9.38 mg/L;但NH+4-N去除率则降低了26.25%,TP去除率降低了21.21%。