柊叶和象草波式潜流人工湿地的对比研究

为探索柊叶和象草在人工湿地中的应用及其净化机理,该研究以柊叶和象草为人工湿地植物分别构建了波式潜流人工湿地系统,分析了柊叶和象草波式潜流人工湿地对生活污水中COD_(cr)、TN和TP的净化效果,观察了柊叶和象草两种植物在不同季节的生长状况。结果表明:经过15个月的连续运行,在表面水力负荷约0.3 m·d~(-1)的条件下,柊叶和象草波式潜流人工湿地平均去除率是COD_(cr)分别为66.1%和70.1%,TN分别为60.4%和63.7%,TP分别为74.1%和75.1%。两种植物生长良好,根系发达,象草的地上生物量是柊叶的2.1倍,地下生物量相当;冬季象草生长缓慢,柊叶部分叶片的四周干枯,但二者都不会枯亡。这说明两个人工湿地对COD_(cr)、TN和TP都具有较好的去除效果,但无显著性差异,柊叶和象草能明显提高潜流人工湿地的净化效果。     

5种湿地植物对生活污水净化效果研究

选择芦苇、水葱、千屈菜、扁秆藨草、长苞香蒲5种常见湿地植物分别构建人工湿地小试系统,测试它们对生活污水的净化作用,分析污水净化过程中氮磷元素在植物体内和土壤中的动态分布,以明确各湿地植物对污水的综合净化能力。结果表明:（1）5种湿地植物对生活污水中的CODcr、铵态氮、总氮和总磷的去除效果显著高于无植物对照;随处理时间延续,污水中CODcr、铵态氮、总氮和总磷浓度均呈下降趋势,定植土壤中的总氮和总磷含量呈先上升后下降的变化趋势。（2）5种植物能够吸收污水中89.7%～97.9%的磷元素,污水中剩余的磷元素量较少（2.1%～10.3%）;污水中氮元素在植物体、污水和土壤中分布因植物种类不同有很大差别,芦苇、水葱和长苞香蒲可吸收污水中76.1%～83.4%的大部分氮元素,而千屈菜和扁秆藨草对氮元素吸收量较少（分别为45.0%和46.8%）,在污水和土壤中滞留的氮元素较多（21.7%～31.6%）。（3）5种植物对氮元素的积累能力显著大于对磷元素的积累能力;5种湿地植物对生活污水的综合净化能力差异较大,从强到弱依次为芦苇＞长苞香蒲＞水葱＞扁秆藨草＞千屈菜。     

潜流湿地和表面流湿地的净化效果与植物生长比较

分别以砾石和土壤为填料构建成潜流人工湿地和表面流人工湿地,处以较大水力负荷的污水处理。比较了两种湿地对污水的净化效果,结果表明在较大水力负荷条件下两种湿地的净化效果都较差,但潜流湿地对各种污染物的净化能力都优于表面流湿地;土柱法测量了湿地植物的根系生物量,结果显示湿地植物地上部分长势差异不明显,但潜流湿地的根系生物量显著低于表面流湿地的根系生物量(P<0.05)。结合前期实验结果得出湿地净化效果不仅与湿地植物根系生物量有相关关系,还与其他因素有一定的相关关系。     

4种不同生活型湿地植物对富营养化水体的净化效果

选择4种湿地植物菖蒲、香蒲、浮萍和金鱼藻,研究单一及组合湿地植物对高浓度污水(污水处理厂进水)、低浓度污水(污水处理厂出水)中营养物质的去除效果.结果表明: 水体中总氮(TN)、总磷(TP)、化学需氧量(COD)浓度呈现试验前期快速下降,后期缓慢下降的趋势,表明湿地植物能有效净化污水中的TN、TP、COD,但不同湿地植物及湿地植物组合的净化效果存在差异.多种湿地植物组合比单种湿地植物对TN的净化作用强,其中香蒲＋浮萍＋金鱼藻对TN的净化效果最佳;高浓度污水中,单种挺水植物对TP的净化效果较好,低浓度污水中,则是多种湿地植物组合对TP的去除率较高;高浓度污水中,湿地植物对COD的去除率为85.1%～96.0%,其中菖蒲、香蒲去除效果最佳,低浓度污水中,湿地植物对COD去除率为76.9%～94.8%,以菖蒲＋浮萍＋金鱼藻去除效果最好.总体看来,湿地植物对高浓度污水中TN、TP、COD的净化效果好于低浓度污水,两种水体的pH都得到改善.     

人工湿地的氮去除机理

湖泊等水环境的富营养化给人类带来诸多损害,如环境、生态和经济等方面的损害。富营养化的原因和控制途径引起了包括中国在内的很多国家的关注。我国针对水环境的富营养化问题开展了大量的工作。氮是引发水环境富营养化的主要营养物之一。外源氮负荷（分点源和非点源两部分）是水环境污染负荷的重要组成部分。传统污水处理技术应用于收集系统欠缺的非点源污染的治理时成本过高。人工湿地是有效削减水环境中外源氮负荷的重要技术手段,在处理非点源污染源带来的氮负荷时更是如此。人工湿地具有氮去除效果好、耐冲击负荷能力强、投资低和生态环境友好等优点。因此人工湿地非常适合于水环境富营养化的防治。阐明人工湿地中氮的去除机理对水环境的富营养化等具有重要的意义。防渗人工湿地的氮去除机理主要包括挥发、氨化、硝化／反硝化、植物摄取和基质吸附。未防渗的人工湿地中,周围水体与人工湿地的氮交换影响着人工湿地中氮的去除。一般情况下,人工湿地中硝化／反硝化是最主要的氮去除机理。pH值小于7．5时,氨挥发可忽略。pH值在9．3以上时,氨挥发很显著。处理生活污水的人工湿地中氮的去除主要是依靠微生物的硝化／反硝化作用。在进水负荷低、气候适宜、植物物种适宜和收割频率与时机适宜的条件下,植物收割可能成为主要的去氮途径。人工合理导向的湿地的氮去除效果通常优于天然湿地。合理的设计（填料的搭配、植物物种的配置以及布水和集水的优化）对人工湿地系统中氮去除的改善有重要影响。合理的运行,如有效的水位控制,正确的植物培育、合理的植物收割等,能有效地改善湿地中的氮去除。     

北京地区人工湿地植物活力及污染物去除能力

研究了北京地区常见9种水生植物在水平流潜流型人工湿地中的污染物去除能力和生活力.结果表明,前边湿地单元对COD、TP、TN等污染物的去除贡献大于后边湿地单元.供试植物均可在人工湿地中正常生长,稳定生长112 d后,不同植物的氮磷含量和生物量差异显著（P<0.05）,多数植物氮磷含量地下部高于地上部,地下地上部生物量比（U/A）接近或大于1.植物体内的氮磷累积量为1.36～7.89 g·m^-2和0.19～1.07 g·m^-2.植物生物量对氮磷累积量的影响力大于氮磷含量对氮磷累积量的影响力.水生鸢尾应为北京地区首选人工湿地植物,菖蒲、香蒲和荻等次之.泽泻和芦竹在人工湿地中不能越冬成活.     

低温状态下潜流湿地的氮磷去除效果

以汉石桥潜流湿地为研究对象, 通过对2014 年10 月-次年5 月中水出水水体氮磷元素去除率分析, 研究潜流湿地对水中氮磷元素的去除效果。结果表明: TN、NH₄ ⁺、NO₂ ^– 、NO₃ ^– 、TP、PO₄^3–平均去除率为23.09%, 47.68%, 39.66%,29.96%, 23.79%, 29.73%, 且各个指标去除率均表现为先降低后增加的趋势, 整体去除率均为正值, 说明该潜流湿地在秋冬春季具有一定的处理效果; pH 与温度为制约该潜流湿地氮元素去除的重要因素, 而磷元素去除受到温度影响较小;虽然冬季潜流湿地仍有一定的去除氮磷的效果, 但去除率过低, 应注重保温, 才能使潜流湿地更有效率的全年运行。     

人工湿地处理炼油废水的生态效益研究

来自茂名石化公司的炼油废水含有较高浓度的污染物 ,超过广东省规定的排放标准 ,未经处理不能直接排放。 4种草本植物 ,香根草、芦苇、宽叶香蒲和蒲草被用来测试建植人工湿地的效果以及所建植的人工湿地处理炼油废水的效果。在为期 2个月的处理过程中 ,人工湿地在前期对炼油废水的净化效率很高 ,它们对第一批高浓度废水中氨氮、COD、BOD和油的去除率分别是 97.7%、78.2 %、91 .4%和 95 .3% ,对第一批低浓度污水分别是 97.1 %、71 .5 %、73.7%和 89.8%。但是 ,随着时间的推移 ,湿地的净化效果会有一定程度的下降 ,然后逐渐趋于稳定。湿地对氨氮、COD、BOD和油类的去除效率始终表现为氨氮 >油类 >BOD>COD,但植物对它们的净去除量却是 COD>BOD>氨氮和油类。湿地建植之初 ,植物的净化功能很弱 ,但随植物的生长和生物量的增加而逐渐增强。然而 ,不同植物种对废水的净化率很接近 ,基本上无显著性差异。被测试的 4种植物在污水湿地中的生长表现都好过在清水湿地中的 ,但香根草、芦苇和宽叶香蒲在高浓度废水的分蘖数比在低浓度的废水少些 ,而蒲草相反 ,表明高浓度污水相对于低浓度污水而言已经对前面 3个种产生了伤害 ,却仍促进蒲草生长。在清水培养阶段 ,香根草产生分蘖的速度是 4个种中最低的 ;进入污水培养阶     

波形潜流人工湿地污水处理的研究

波形潜流人工湿地包括水平流、上行流和下行流在内的混合流态,集合了潜流人工湿地和垂直流人工湿地的优点,优于传统潜流人工湿地。本文主要结合波形潜流人工湿地的特点,探讨波形人工湿地微生物群落结构及污染物去除机理,为强化波形潜流人工湿地的净化功能提供参考。     

几种湿地植物净化生活污水COD、总氮效果比较

以无植被、基质为河砂的潜流型人工湿地为对照,研究了石菖蒲、灯心草和蝴蝶花3种类型植被、基质均为河砂的潜流型人工湿地净化生活污水COD、总氮的效果．结果表明,在污水COD浓度小于200mg·L^-1、总氮浓度小于30mg·L^-1的低浓度范围里,无植被的人工湿地和有植被的人工湿地对污水中COD、总氮均有很好的去除效果,两者差异不大,其COD去除率均达90％以上,总氮的去除率达80％以上．随着污水中COD和总氮浓度的增加,无植被人工湿地和有植被人工湿地去除COD和总氮的效果均有不同程度下降,两者差异明显,有植被的人工湿地能维持较高的COD、总氮的去除效果,无植被的人工湿地COD和总氮去除效果下降很快,植被在人工湿地系统去除污水COD和总氮过程中起着重要的作用．在整个试验阶段,石菖蒲植被人工湿地COD和总氮平均净化效率分别为80．46％和77．77％、灯心草人工湿地分别为75．53％和71．17％、蝴蝶花人工湿地分别为70．50％和66．38％,无植被人工湿地分别为61．39％和55．81％．同无植被人工湿地COD和总氮净化效果相比,石菖蒲植被人工湿地净化效果最好;其次为灯心草植被人工湿地,再次为蝴蝶花植被人工湿地．不同类型植被的人工湿地净化污水中COD和总氮的效果与其生物量关系密切,这与植被系统吸收同化有机物质和总氮数量、根际微生物分解有机物质和硝化-反硝化作用有关。     

The Potential of Canna lily for Wastewater Treatment Under Indian Conditions

Low cost treatment of polluted wastewater has become a serious challenge in most of the urban areas of developing countries. The present study was undertaken to investigate the potential of Canna lily towards removal of carbon, nitrogen, and phosphorus from wastewater under sub-tropical conditions. A constructed wetland (CW) cell supporting vegetative layer of Canna lily was used to treat wastewater having high strength of CNP. Removal of biological oxygen demand (BOD₃) and chemical oxygen demand (COD) varied between 69.8–96.4% and 63.6–99.1%, respectively. C. lily could efficiently remove carbon from a difficult to degrade wastewater at COD:BOD ratio of 24.4. Simultaneous reduction in TKN and nitrate pointed to good nitrification rates, and efficient plant assimilation as the dominant nutrient removal mechanism in the present study. Suitable Indian agro-climatic conditions favored plant growth and no evident stress over the Canna plant was observed. High removal rate of 809.8 mg/m²-day for TKN, 15.0 mg/m²-day for nitrate, and 164.2 mg/m²-day for phosphate suggests for a possible use of Canna-based CW for wastewater treatment for small, rural, and remote Indian communities.     

Comparison of free water and horizontal subsurface treatment wetlands

The two most prevalent types of treatment wetland, especially during the early history of the technology, are free water surface (FWS) and horizontal subsurface flow (HSSF) wetlands. The several factors involved in the choice of which alternative to choose include size, cost, operability, together with health and nuisance issues and ancillary benefits. Contaminant removal performance differs by constituent, with the advantage to FWS for moderate to high biochemical oxygen demand (BOD), TSS, ammonia, total nitrogen and phosphorus. HSSF are more effective for tertiary BOD levels, nitrate and pathogens. Superpositions of the loading data show that the respective data clouds overlap virtually entirely for HSSF and FWS wetlands. There is little or no performance difference when they are compared on this areal basis. In general, there is little or no advantage of HSSF for space saving. In cold climates, HSSF systems are less cold sensitive, and easier to insulate for winter operation. The use of winter storage enables FWS to be used in freezing conditions, but the cost makes that option comparable to the more expensive HSSF. In general, economics do not favor the choice of HSSF wetlands. Factors other than reduction performance are also important in the selection process. Other principal reasons for selecting the HSSF option over the FWS option are prevention of human health contact problems, mosquito control and minimization of wildlife interactions.     

Clogging in horizontal subsurface flow constructed wetlands: influencing factors,research methods and remediation techniques

The treatment of wastewater in constructed wetlands (CW) has been increasingly applied throughout the world, as it is an efficient technique for the removal of pollutants and presents low construction and operational costs. However, a major operational problem of these systems is clogging of the porous medium. Clogging of CW has therefore attracted the attention in several studies, but there are several gaps in the understanding of this phenomenon, especially with regards to its genesis. In order to evaluate the contribution of the influencing factors and to facilitate remediation, it is important to have methods that favor characterization of the real conditions of CW. In this review, the objective was to gather information on the main factors interfering in the clogging process of horizontal subsurface flow constructed wetlands, the available and the new methods for characterizing the degree of obstruction of the porous medium and the techniques/strategies for unclogging these systems.     

Polishing domestic wastewater on a subsurface flow constructed wetland: organic matter removal and microbial monitoring

Microbial monitoring of constructed wetlands (CWs) treating domestic wastewater is generally scarce, despite the need of more knowledge about its biocenosis. The sanitation quality of a wastewater treated in a CW is a crucial aspect, mainly when the receiving water body is used as a swimming and/or recreation area. The present study was carried out in a horizontal subsurface flow CWplanted with Phragmites australis receiving pre-treated domestic wastewater (mean flow 50 m3 day(-1)), from a population of about 300 inhabitants. The monitoring programme undertaken during the first year operation, revealed removal efficiencies of 61% BOD5, 44% COD, and 65% TSS for inlet water with ca. 90 mg L(-1) BOD5, 157 mg L(-1) COD, and 17 mg L(-1) TSS. Total Coliform (TC) and Faecal Coliform (FC) bacteria were removed from wastewater (mean inlet values of 5 x 10(6) CFU 100 mL(-1) TC and of 9 x 10(5) CFU 100 mL(-1) FC), with efficiencies of 92 and 97%, respectively. The dynamics of microbial communities established in the system assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), had revealed a high bacterial diversity within the system, with no relevant differences in composition at the CW inlet and outlet but exhibiting temporal differences in bacterial communities.     

A comparison of bacterial removal efficiencies in constructed wetlands and algae-based systems

Constructed wetlands and algae-based systems have been compared regarding their efficiencies on faecal bacteria removal. Two types of constructed wetlands, sub-surface (SSF) and free water surface (FWS) flow systems, and two more types of algae-based systems, high rate algae ponds (HRAP) and maturation pond (MP) have been studied for two years. All systems treated the same wastewater from a rural locality in León (northwest of Spain). Hydraulic retention time was 3 days for both wetland systems, 20 days for the maturation pond and 10 days for the high rate algae pond. Total coliforms, faecal coliforms, faecal Streptococci, Clostridium perfringens, and Staphylococci were analyzed in the influent and effluents of each system. A comparison among the wetland systems showed that SSF were more efficient than FWS system when considering surface removal rates (cfu removed/m²/d). Nevertheless, differences were not statistically significant. Considering mean removal efficiencies (in log unit), results showed that higher reductions were observed in FWS for most of the groups except for clostridia and Staphylococci. Concerning algae-based systems, MP showed higher removal efficiencies than HRAP, getting higher surface removal rates in the HRAP. Generally constructed wetlands were more efficient than algae-based systems when considering both, efficiencies in % and surface removal rates.     

Effect of operational and design parameters on removal efficiency of pilot-scale FWS constructed wetlands and comparison with HSF systems

In order to investigate the effect of temperature, hydraulic residence time (HRT), vegetation type, substrate material and wetland shape on the performance of free-water surface (FWS) constructed wetlands treating wastewater, 5 pilot-scale units were constructed and operated continuously from December 2004 until March 2007 in parallel experiments. Four of the units (A, B, C, D) were rectangular in plan view with dimensions 3.40 m in length and 0.85 m in width, and contained substrate material at a thickness of 0.45 m. The fifth unit (E) had a trapezoidal plan view shape, with a width at the inlet of 1.15 m and at the outlet of 0.55 m, while the length and the thickness of the substrate were the same as in the other four. All units operated at a water depth of 0.10 m. Units B–E contained clay substrate and unit A contained sand. The four units with clay were planted as follows: two with cattails (B and E), one with common reeds (C), and one with giant reeds (D). Unit A, containing sand, was planted with cattails. Planting and substrate material combinations were appropriate for comparison of the effect of vegetation and material type on the function of the system. Synthetic wastewater was introduced in the units. During the operation period four HRTs (i.e., 6 days, 8 days, 14 days and 20 days) were used, while wastewater temperatures varied from about 0.0 °C to 29.1 °C. The removal performance of the five constructed wetland units was good, since it reached on the average 77.5%, 67.9%, 60.4%, 53.9%, 56.0% and 51.7% for BOD, COD, TKN, ammonia (NH₄-N), ortho-phosphate (PO₄-P) and total phosphorus (TP), respectively. BOD and phosphorus removal efficiencies showed dependence on temperature in most units. The 14-day HRT was found adequate for acceptable removal of organic matter, nitrogen and phosphorus for most temperatures. A 20-day HRT is recommended for acceptable removal of BOD and PO₄-P in the cold season. The unit with the trapezoidal plan view shape showed the best performance, with mean removals of 80.1%, 73.5%, 70.4%, 68.6%, 64.7% and 63.5% for BOD, COD, TKN, NH₄-N, PO₄-P and TP, respectively. The cattail was found statistically more efficient than the other two plants in COD and PO₄-P removal. The unit that contained the clay substrate was found statistically more efficient in phosphorus removal than the unit containing sand. HSF CW units were found more efficient than FWS units in removal of most pollutant.     

Comparison of the performance of horizontal and vertical flow constructed wetland planted with Rhynchospora corymbosa

Treatment performance of horizontal flow (HF) and vertical flow (VF) constructed wetland planted with Rhynchospora corymbosa were compared. The average porosity of the CW beds were 0.55, hydraulic retention time (HRT) of 3?days, hydraulic loading rate (HLR) and Organic Loading rate were 0.058?m/day and 3.96 (g·BOD/m²·day), respectively with a volumetric flow rate of 0.14 m³/day. The pollutant concentration of graywater before and after its introduction to the CWs was measured using standard sampling and analyses methods. The mean removal efficiencies (RE) for HF and VF CWs were BOD, 35% and 35.4%; COD, 61.9% and 56.7%; TN, 87% and 92%; TP, 95% and 65%; TSS, 86% and 59.6%; pH, 8.8% and 12.8%, respectively. The graywater was highly contaminated in terms of nutrient and organic load. The mean values of the parameters tested for different CWs were significantly different (P?≤?0.05). This comparative study favored HF over VF Constructed wetland with HF found to be a viable alternative for graywater treatment for organics, nutrients and suspended solids removal. The result provided insight into the performance of CWs planted with R. corymbosa.     

生物传感器快速测定BOD的研究

生化需氧量(biochemicaloxygendemand,BOD)是一种表征水体有机污染程度的综合指标,广泛应用于水体监测和废水处理厂的运行控制。由于BOD的标准测定方法需时5天,不能及时地反映水质状况和反馈处理信息,因此快速测定BOD的方法和仪器化研究近年来得到广泛的重视。利用生物传感器测定BOD是一种有效地快速测定废水中可生化降解有机物的方法。介绍生物传感器的工作原理及其生物敏感材料,讨论BOD传感器的性能参数以及BOD快速测定值(BODst)与标准BOD5值的一致性问题。对现阶段市场上常见的几种BOD快速测定仪进行简单的介绍,并对它们的性能进行比较 。