人工湿地小试系统藻类去除效果的变化研究

夏季在水力负荷为800mm/d间歇式进水条件下,研究了人工湿地不同工艺流程的8套小试系统SSP（system of small plot）内部水流方向上藻类去除率的变化。结果表明：人工湿地小试系统中,藻类生物量沿水流方向逐渐减少,除藻率在出水处均达到最大值。藻类的去除主要发生在湿地水流方向的前几层,而系统其他层对藻类只有微弱的去除效果。由下行池与上行池构成的湿地系统中,去藻是上、下行池共同作用的结果。在有推流床或塘处理系统参与的湿地系统中,它们对藻类的去除均有一定的作用。去藻作用主要是基质的拦截,不同的水流方向、植物和微生物也起到了一定作用。湿地对藻类的去除率在夏季一般都能达到90%以上,证明人工湿地是一种有效的除藻生态-生物方法,对除藻要求比较高水体的湿地构建及工艺流程的设计、组合具有重要意义。     

水量衡算条件下人工湿地对有机物的去除

构建了芦苇和无植物人工湿地,在系统水量衡算的基础上比较了两种湿地对生活污水中有机物的去除效果。结果表明,在植物收割后的冬季,有植物湿地对有机物的去除率低于无植物湿地2.2%;在其他季节,芦苇湿地对污水CODCr的去除率比无植物的高出3.2%～4.2%,但对BOD5的去除率却比无植物的低了1.8%～3.4%。有植物湿地对有机物的去除效果比无植物湿地有所改善,但是提高不多。比较了两种系统的氧化还原电位,有植物湿地比无植物湿地高（P<0.05）,这种提高主要集中在湿地水面以下约15 cm的范围,从整体来看,两块湿地内部氧化还原状态大体相同,主要是强还原环境。比较了两块湿地基质中降解有机物的细菌、放线菌和真菌的数量,二者没有明显的差别,但是,有植物湿地的根际效应明显。考察了湿地进水有机负荷与去除量的关系,二者呈现显著的线性相关性(R2>0.96)。      

构建湿地去除酞酸酯的基质微生物和酶机制研究

随着塑料制品的广泛使用，酞酸酯的污染越来越引起人们的广泛关注。目前，DBP(邻苯二甲酸二丁酯)和DEHP(邻苯二甲酸二异辛酯)已成为全球最普遍的污染物之一。报告了复合垂直流构建湿地对含酞酸酯(DBP等)的污水污染的去除效果，以及湿地去除酞酸酯的基质微生物和酶方面的净化机理。具体结果如下：复合垂直流构建湿地对酞酸酯污染具有较好的净化效果，去除率高达99．9％以上；构建湿地对酞酸酯的净化主要发生在氧气含量相对较多的下行流池，上行流他的净化作用相对较差；同时分层实验还发现，构建湿地的净化作用主要集中在湿地上层基质中。通过研究，为进一步研究利用构建湿地处理酞酸酯污染提供了有益的参考。     

人工湿地系统去除藻毒素研究

以含水华的鱼塘水作为进水灌溉两套上行流－下行流人工湿地系统,系统内种植芦苇等水生植物。灌溉一周后收集人工湿地进出水水样,用ＨＰＬＣ法检测其藻毒素定量,结合温度、电位、溶氧等理化指标和细菌、藻类数量的变化,分析人工湿地系统对藻毒素的去除效果及影响其效果的可能因素。结果表明,人工湿地系统对藻毒素有一定的去除效果优于茭白－石菖蒲组合的湿地系统。在三种主要藻毒素ＲＲ、ＹＲ、ＬＲ中,湿地对ＹＲ的去除效果最好     

复合垂直流构建湿地净化污水机制研究——Ⅰ 微生物类群和基质酶

构建湿地是20世纪70年代才蓬勃兴起的一种处理污水的方式，由于其造价和运行费用低，净化效果稳定，越来越引起各国的兴趣和高度重视。现已广泛应用于城市生活污水，工业污水和农业污水水的农业，有着十分广阔的应用前景。虽然关于构建湿地净化污水的研究有不少报道，但关于湿地基质中的微生物类群和基质酶在污水净化中的作用仍不清楚。通过对生长在复合垂直流构建湿地天然环境条件下菰和石菖蒲根区微生物类群数量及其根区基质酶活性的测定发现：同种植物在复合垂直流构建湿地根区微生物的数量比天然条件下的要高，特别是硝化细菌和反硝化斩数量，最高可达3个数量级以上；同时复合垂直流构建湿地中不同植物要的酶活性有较大差别，这为研究复合垂直流构建湿地净化污水的机理和以酶活性强弱作为净化效果的评价指标提供了科学资料，为进一步研究提供了一条新思路。     

基于BMPs的鄱阳湖区小流域农村面源污染控制

鄱阳湖小流域农村面源污染严重，环境问题不断加剧。通过背景值调查与污染源解析，显示农村生活和种植业是鄱阳湖小流域农村面源污染的主要来源。采取集成式BMPs模式，将源头控制与末端治理相结合，充分利用当地优势，合理搭配植物缓冲带、沟渠湿地、人工湿地，兼性塘等，实现氮、磷流失的有效拦截，达到有效控制示范区小流域农村面源污染目的，从而为鄱阳湖农村面源污染控制提供借鉴。结果表明： BMPs系统污染物去除能力高，运行成本低。系统单位面积削减总量分别为CODcr 71017 kg、SS 11491 kg、TP 408 kg、TN 3593 kg、NO-3 N 474 kg、NH+4 N 1918 kg，而运行成本不到01元/t。整个系统中尤以表面流人工湿地减污效果最好，耐负荷冲击能力最强。沟渠湿地整体去污能力不低，但耐冲击负荷能力弱，易受外界因素的影响。为加强减污效果，可通过完善生态系统尤其是挺水性植物加以改进     

八种不同工艺组合人工湿地系统除磷效果研究

传统的人工湿地系统除磷效能的提高方式主要集中在基质填料的选择、湿地植物的筛选等方面,本试验从调整湿地的组合工艺着手探索提高磷去除效率的优化组合,在为期两年的研究中考察了推流床-下行流-上行流、下行流-上行流-推流床、好氧塘-下行流、下行流-兼性塘、推流床-下行流、下行流-上行流、推流床等8种不同工艺组合人工湿地系统对富营养化湖泊水体中磷的去除规律,比较了这些湿地组合所构建的生物学效应。试验结果显示,如果采用塘系统作组合单元在湿地系统中前置比较理想,而在不同的季节,不同水力负荷下的冲击试验结果表明,复合垂直流湿地系统可以常年保持稳定的、较高的磷去除能力,而且对水力变化具有更好的耐受性能。复合垂直流湿地作为一种新型的人工湿地系统工艺组合具有较好的理论价值和应用前景.     

水生高等植物对悬浮泥沙的去除研究

根据自然水体湿生植物（挺水植物）、浮叶植物以及沉水植物的空间分布规律，利用风车草（Cyperus alternifolius）、石菖蒲（Acorus tatarinowii）、菱（Trapa japonica）、金鱼藻（Ceratophyllum demersum）、轮叶黑藻（Hydrilla verticillata）和苦草（Vallisneria spiralis）等水生植物构建由挺水植物、浮叶植物到沉水植物的串联系统，含沙水依次流经挺水植物、浮叶植物和沉水植物，测定各级植物对泥沙的去除效果。结果显示，输入悬浮泥沙浓度依次为21.76、37.04、45.09、71.18 mg/L，水力停留时间（HRT）分别为12、16、24、24 h，水生高等植物串联系统对悬浮泥沙的去除率分别为68.1%、71.7%、77.5%、74.0%，表明水生高等植物可有效去除水体中的悬浮泥沙，改善了透明度。水力滞留时间对植物去除悬浮泥沙的效果有较大的影响，水力滞留时间长，即使输入悬浮泥沙浓度很高，去除率和单位时间的净去除量也较高;浅水区的挺水植物对进水高浓度悬浮泥沙的有效过滤作用减缓了悬浮泥沙对深水区沉水植物的胁迫压力;沉水植物能进一步去除悬浮泥沙，抑制再悬浮作用，对水生生态系统的稳定有十分重要的作用。     

复合垂直流构建湿地净化污水机制研究 Ⅰ微生物类群和基质酶

构建湿地是 2 0世纪 70年代才蓬勃兴起的一种处理污水的方式 ,由于其造价和运行费用低 ,净化效果稳定 ,越来越引起各国的兴趣和高度重视。现已广泛应用于城市生活污水、工业污水和农业污水的控制 ,有着十分广阔的应用前景。虽然关于构建湿地净化污水的研究已有不少报道 ,但关于湿地基质中的微生物类群和基质酶在污水净化中的作用仍不清楚。通过对生长在复合垂直流构建湿地和天然环境条件下菰和石菖蒲根区微生物类群数量及其根区基质酶活性的测定发现 :同种植物在复合垂直流构建湿地根区微生物的数量比天然条件下的要高 ,特别是硝化细菌和反硝化细菌的数量 ,最高可达 3个数量级以上 ;同时复合垂直流构建湿地中不同植物根区的酶活性有较大差别 ,这为研究复合垂直流构建湿地净化污水的机理和以酶活性强弱作为净化效果的评价指标提供了科学资料 ,为进一步研究提供了一条新思路     

复合垂直流构建湿地净化污水机制研究 I微生物类群和基质酶

构建湿地是20世纪70年代才蓬勃兴起的一种处理污水的方式,由于其造价和运行费用低,净化效果稳定,越来越引起各国的兴趣和高度重视.现已广泛应用于城市生活污水、工业污水和农业污水的控制,有着十分广阔的应用前景.虽然关于构建湿地净化污水的研究已有不少报道,但关于湿地基质中的微生物类群和基质酶在污水净化中的作用仍不清楚.通过对生长在复合垂直流构建湿地和天然环境条件下菰和石菖蒲根区微生物类群数量及其根区基质酶活性的测定发现:同种植物在复合垂直流构建湿地根区微生物的数量比天然条件下的要高,特别是硝化细菌和反硝化细菌的数量,最高可达3个数量级以上;同时复合垂直流构建湿地中不同植物根区的酶活性有较大差别,这为研究复合垂直流构建湿地净化污水的机理和以酶活性强弱作为净化效果的评价指标提供了科学资料,为进一步研究提供了一条新思路.     

复合垂直流人工湿地氧化还原特征及不同功能区净化作用研究

研究了复合垂直流人工湿地系统氧化还原电位（Eh）的时空变化规律及不同功能区中污染物的净化效果。结果表明：湿地系统下行流池表层、两池底层、上行流池表层Eh的变化范围分别为402～585、-87～-130、308～432 mV，沿水流方向依次形成了好氧A区/缺氧、厌氧区/好氧B区3个功能区。好氧A区是污染物去除的主要区域，BOD₅、COD_Cr、NH⁺_4- N的去除率分别为430%、484%、541%，特别是NH+4 N去除率占总去除率的79%；缺氧、厌氧区主要是进行反硝化反应和有机物的厌氧分解；好氧B区则主要是去除厌氧分解后的有机物以及进一步脱氮。另外，NH+4 N的去除率与系统各功能区Eh呈显著相关关系（〖WTBX〗p〖WTBZ〗＜001），而BOD₅、COD_Cr、NO^-_3-N的去除率与系统各功能区Eh相关性不显著。     

Simultaneous biological removal of endosulfan (alpha+beta) and nitrates from drinking waters using wheat straw as substrate

Nitrate and endosulfan (alpha+beta) removal was studied in an upflow biological denitrification reactor packed with wheat straw as carbon source and support particles for microorganisms. While almost complete nitrate elimination and between 65% and 70% endosulfan (alpha+beta) elimination occurred when the temperature was higher than 20 degrees C; below that value, nitrate removal efficiency decreased to about 10%. Nitrate, dissolved organic carbon (DOC), and endosulfan (alpha+beta) removal efficiencies decreased considerably at 1500 microg/l endosulfan concentration in the batch experiments. Although a high removal efficiency was observed for endosulfan (alpha+beta) and nitrate in the biological denitrification continuous reactor, the effluent water could not be used for drinking purpose because of the unacceptable levels of endosulfan (alpha+beta), colour and dissolved organic content. During the continuous study, 23.4% of the initial weight of wheat straw was lost and 24 g was consumed per gram of nitrogen removed. The results of the continuous study showed that 21.3% of the endosulfan removal was achieved by adsorption onto the wheat straw and 68.2% of the endosulfan removal occurred by biological activity and the remaining portion was detected in the effluent water.     

Phytoaccumulation of heavy metals by aquatic plants

Three aquatic plants were examined for their ability to remove heavy metals from contaminated water: parrot feather (Myriophylhum aquaticum), creeping primrose (Ludwigina palustris), and water mint (Mentha aquatic). The plants were obtained from a Solar Aquatic System treating municipal wastewater. All the three plants were able to remove Fe, Zn, Cu, and Hg from the contaminated water. The average removal efficiency for the three plant species was 99.8%, 76.7%, 41.62%, and 33.9% of Hg, Fe, Cu, and Zn, respectively. The removal rates of zinc and copper were constant (0.48 mg/l/day for Zn and 0.11 mg/l/day for Cu), whereas those of iron and mercury were dependent on the concentration of these elements in the contaminated water and ranged from 7.00 to 0.41 mg/l/day for Fe and 0.0787 to 0.0002 mg/l/day for Hg. Parrot feather showed greater tolerance to toxicity followed by water mint and creeping primrose. The growth of creeping primrose was significantly affected by heavy metal toxicity. The selectivity of heavy metals for the three plant species was the same (Hg>Fe>Cu>Zn). The mass balance preformed on the system showed that about 60.45-82.61% of the zinc and 38.96-60.75% of the copper were removed by precipitation as zinc phosphate and copper phosphate, respectively.     

Mosquito larvae density and pollutant removal in tropical wetland treatment systems in Honduras

Constructed wetlands offer a low-cost wastewater treatment option for tropical developing countries. The vast majority of published treatment wetland research has been conducted in temperate regions. Because the function of treatment wetlands is related to the environmental conditions, more research specific to the tropics should be completed. A six-cell free water surface (FWS) wetland mesocosm was constructed in Santa Rosa de Copán, Honduras that received input from an open-sewer/wastewater-impacted stream. Three cells were planted with Typha domingensis Pers., and three cells were left unplanted. Both planted and unplanted wetlands were constructed with three different surface areas to concurrently study different hydraulic retention times (HRTs) and hydraulic loading rates (HLRs). Results from 6 months of operation showed improved water quality and mosquito larvae populations affected by their specific environment. Five-day biochemical oxygen demand (BOD) removal appeared to be proportional to HRT and HLR, and BOD concentration in the effluent was higher in unplanted cells than in planted cells (P<0.05). BOD removal approached 60% for greater than 3.5 days HRT. Total phosphorus (P) removal and coliform bacteria removal were found to be correlated with pollutant load, and P removal was found to be correlated with HRT but not HLR. A second municipal wastewater FWS treatment wetland in Copán Ruinas, Honduras that had been established for 15 years, was also evaluated. BOD removal in the Copán Ruinas system was determined to be 93% with 2.6 day HRT. These pollutant removal rates are higher than would be expected in temperate regions. Mosquito larvae density was correlated with depth of the wetland. Mosquito larvae densities were higher in cells that were operating below design depth of 0.2 m (P<0.005). Results indicate that it is possible to design FWS wetlands in the tropics for effective BOD removal and reduced mosquito larvae development.     

Biogas plants efficiency in purifying Indian sago factory waste water with wide C/N ratios: strategies for process water reuse

Cassava tubers produced under hot, dry and monsoon governed climate in the Salem region, Tamil Nadu, South India, consume together with the about 1000 starch extracting industries daily, 9 millions of litres of groundwater which have to be pumped from a depth of 80 m below ground level. Because of water shortage, adjacent fields are irrigated with organically highly enriched sago factories wastewater and the land becomes unproductive. One-third of the wastewater is presently channelled through a few installed biogas plants with a purification efficiency, biological oxygen demand, of only around 30%. Microbiologically and chemically analysed in- and effluents of biogas plants exhibited nutrient contents sufficient to maintain a rice crop and significantly higher population densities of fermenting bacteria and methanogenic archaea, despite C/N ratio of about 250. CO₂ and CH₄ emissions from aerobic and anaerobic incubated sago factory biogas plants in- and effluents indicated that the present purification efficiency of 30% can be further enhanced. This investigation has given clues for designing a purification system that connects the already installed biogas plants with a well-aerated, hydro-cultured, constructed wetland and a Stirling motor device for electric power gains and heat distillation, for enabling reuse of process water and saving groundwater.