潜流人工湿地氮素去除机理与影响因素

综述了氮化合物去除的机理和转化规律,指出提高氮素去除率的新途径。在研究了温度、p H值、溶解性有机碳、溶解氧等因素的基础上,以及水力停留时间、氮负荷、回流、进水方式等的配置模式的概述,来探究环境因素和运行条件对潜流人工湿地除氮效果的影响。     

地沟油合成烷醇酰胺研究进展

简要介绍了地沟油的危害性,分析了烷醇酰胺的合成方法,甲酯法具有众多优点,是目前广泛使用的合成方法。以地沟油为原料利用甲酯法合成烷醇酰胺首先需要合成脂肪酸甲酯即生物柴油。而生物柴油合成的普遍方法是酯交换法,然后介绍分析了各种酯交换法,对于地沟油这样的高酸值原料油,采用两步酸碱法较为合适。     

垂直潜流人工湿地污水处理特性

垂直潜流人工湿地是一种新型的污水处理技术,在城镇污水资源化中有良好的实用价值和应用前景。通过对特征污染物即有机物、氮和磷的去除研究,阐述了污染物去除的基本特征和作用机理。湿地负荷8.1￣27 g[COD]/(m2.d)范围内,COD去除率为71%￣87%。垂直潜流人工湿地不利于大气复氧,并因而造成NH3-N去除率较低,平均去除率小于10%。TP去除率受温度和季节等因素影响较小,去除率为52%￣77%,但土壤pH值和溶解氧含量却制约着磷的吸附和沉淀作用。并介绍了各运行参数对COD、NH3-N和TP的去除效果的影响规律。     

Effect of supplying a carbon extracting solution on denitrification in horizontal subsurface flow constructed wetlands

Denitrification strongly depends on the availability of carbon source in constructed wetlands (CWs). In this study, several relevant carbon source extracting solutions made from hydrolyzate of selected wetland litters were added to CWs for nitrogen removal enhancement. The feasibility of supplying a carbon extracting solution to improve potential denitrification rate in horizontal subsurface flow constructed wetland was deeply investigated. Combinations of different hydraulic retention time (HRT, especially for 2-day and 4-day) with different influent COD/N ratios were designed to prove the enhancement on denitrification by carbon source supplement. In addition, specific denitrification rate (SDNR) was calculated for the comparison of the nitrogen removal at different COD/N ratios. The sequential operation results on total nitrogen (TN) and nitrate (NO ₃ ^? -N) removal efficiencies were obtained in CW system with an influent COD/N ratio of 4.0. The accumulation of nitrite (NO ₂ ^? -N) was found to be closely related to the removal of NO ₃ ^? -N. Meanwhile, no obvious accumulation of NO ₂ ^? -N was found when the removal of NO ₃ ^? -N was relatively high.     

Investigation of protozoa as indicators of wastewater treatment efficiency in constructed wetlands

Wetlands represent an efficient wastewater treatment technique, with several benefits over the conventional activated sludge system. Microfaunal community is of outmost importance in treatment processes as the microorganisms are able to achieve substantial decontamination through biodegradation. The objectives of this work were the monitoring of protozoan's abundance and diversity in the matrix of six bench scale Free Water Surface constructed wetlands and the investigation of their applicability as indicator organisms for treatment efficiency in these systems. A correlation between the phosphorous and Total Coliforms removal rates was observed in the presence of increased protozoan taxa, while removal of organic loading and inorganic nitrogen was increased in the case of increased protozoan diversity in the soil/water interface. Results revealed that protozoa may be used as bioindicators of treatment efficiency in constructed wetlands; in addition their presence was related to the effluent quality.     

Benzene removal with vertical‐flow constructed treatment wetlands

BACKGROUND: Twelve vertical‐flow experimental wetlands have been constructed using different compositions, and were operated in batch‐flow mode to reduce pumping costs. Six wetlands were located indoors and six outdoors. Benzene was used as a representative example substance to assess the removal of low molecular weight petroleum compounds. RESULTS: Findings indicate that the constructed wetlands remove benzene (inflow of approximately 1.3 g L^?1) from hydrocarbon‐contaminated wastewater streams with better indoor (controlled environment) than outdoor treatment performances. Overall mean removal efficiencies for the experimental rig placed outside were as follows: benzene 85%, chemical oxygen demand (COD), 70%; ammonia‐nitrogen, 83%; nitrate‐nitrogen, 88%; ortho‐phosphate‐phosphorus, 58%. In comparison, removal efficiencies for the experimental rig placed indoors were higher: benzene 95%, COD, 80%; ammonia‐nitrogen, 90%; nitrate‐nitrogen, 94%; ortho‐phosphate‐phosphorus, 66%. Benzene removal was predominantly due to volatilization after 1 day of retention time. CONCLUSION: The use of aggregates (sand and gravel) and the presence of Phragmites australis (Cav.) Trin. ex Steud. resulted in no significant difference in terms of benzene, redox potential, dissolved oxygen, 5‐day at 20 °C N‐allylthiourea biochemical oxygen demand, COD and nutrients removal. Statistical differences were assessed by analysis of variance and Tukey HSD tests (P < 0.05). Copyright © 2007 Society of Chemical Industry     

表面流人工湿地处理农村生活污水工程实例

介绍了表面流人工湿地处理水源地农村生活污水的工艺流程和相关参数,运行结果表明,表面流人工湿地处理农村生活污水效果良好,管理费用低,出水水质可达到GB 18918—2002《城镇污水处理厂污染物排放标准》一级B标准的要求,对改善水源地的水环境质量具有显著作用。     

两级MBfR工艺处理高强度生活废水能力研究

针对受控生态生保系统(CELSS)中生活废水(含卫生废水和尿液废水)的水质特点,采用厌氧、好氧两级MBfR工艺,完成CELSS特征性生活废水的微生物转化处理,以达到循环回用作植物营养液的水质要求。本文研究了水力停留时间(HRT)、尿液强度对该工艺有机物去除及氮素转换效率的影响。试验结果表明,当HRT≥1 d时,HRT对该系统TOC的去除效率无明显影响,其去除效率大于90%,出水TOC的浓度低于15 mg/L;HRT=1 d时,好氧反应器全程硝化能力达到最高,其容积负荷为0.418 kg N/(m³·d);而HRT≥2 d时,能获得相对更为稳定的氮素转换效率。工艺系统最高能处理1/5尿液强度的生活废水,该条件下,系统TOC的去除率达94.3%,出水TOC浓度低于20 mg/L;系统氮素的全程硝化效率为90.6%,且反应器容积负荷较高为0.409 kg N/(m³·d)。本文构建的两级MBfR工艺能较好地实现CELSS中特征性生活废水的有机物去除和氮素的有效转换,研究结果可为CELSS中生活废水微生物处理系统的设计和运行提供参考。     

垂直潜流人工湿地对含油废水净化效果的研究

研究了人工湿地系统中植物生长趋势和水体DO的变化,探讨了污染物的去除与湿地植物生长趋势和水体DO的相关性。结果表明:垂直潜流人工湿地系统对石油类污染物的净化效果很好,且两两系统之间对石油类的去除效果没有显著差异(P>0.05)。石油类污染物去除率与DO相关性较强(r=0.986,P<0.05),与植物生长趋势相关性不显著;栽种植物的湿地系统脱氮除磷的能力均高于对照组。     

垂直流人工湿地用于住宅产业化基地中的水质净化

采用垂直流人工湿地系统综合实现了住宅产业化基地的中水回用、湖水循环净化和雨水利用功能。介绍了系统的工艺流程和设计参数,并对系统稳定运行后的水质进行监测分析。结果表明,处理污水的复合垂直流人工湿地系统对COD、BOD5、TP、NH3-N的总去除率分别为86.5%、95.3%、89.7%、87.5%;循环净化湖水的垂直流人工湿地系统对COD、BOD5、TP、NH3-N的总去除率分别为49.1%、53.2%、50%、60.4%。垂直流人工湿地对主要污染物的去除率在50%以上。     

Performance evaluation of hybrid constructed wetlands for the treatment of municipal wastewater in developing countries

In developing countries, high cost of conventional wastewater treatment is a major hindrance in its application. Constructed wetlands (CWs) offer low-cost and effective solution to this issue. The current study aimed to evaluate an innovative maneuver of CWs i.e. hybrid flow constructed wetlands (HCWs) for municipal wastewater (MWW). The HCWs included two lab scale CWs; one horizontal and one vertical, in series. Local plant species were used. HCWs were operated in both, batch and continuous mode. Batch mode was used to (1) optimize detention time and (2) find pollutants removal efficiency. Continuous operation (at batch optimized retention time) was carried out for the evaluation of mass removal rate, r (g·m^-2·d^-1), volumetric rate constant, K_v (per day) and areal rate constant, K_a (m·d^-1). Among two local plants tested, Pistia stratiotes gave better removal efficiency than Typha. Optimum detention time in HCWs was found to be 8 days (4 + 4 each). The optimum COD, BOD, TSS, TKN and P removal observed for Pistia stratiotes planted HCWs was 80%, 84%, 82%, 71% and 88% respectively. Effluent standards for COD, BOD and TSS were met at optimum conditions. The values of K_a and K_v demonstrated that more removal occurred in vertical flow as compared to horizontal flow CW.     

Effect of limited artificial aeration on constructed wetland treatment of domestic wastewater

To study the effect of limited artificial aeration on domestic wastewater treatment in the constructed wetlands (CWs), four pilot-scale horizontal subsurface flow CWs were operated from October 2006 to September 2007. The types of the four units include aerated and planted CW (APCW), planted CW (PCW), aerated CW (ACW) and CW, and all the units have the identical dimensions of 3 m in length, 0.7 m in width and 1 m in depth. The automated aeration was activated when the oxygen concentrations in the units were lower than 0.2 mg/L and ceased when the oxygen concentrations in the CWs were higher than 0.6 mg/L. More stable alkaline pH values were found in aeration units than that in the non-aeration units. APCW, in which the removal efficiencies of BOD, NH₄⁺-N and TN were 94.4% (16.7 g BOD d^− 1 m^− 2), 89.1% (4.54 g NH₄⁺-N d^− 1 m^− 2), and 86.0%( 4.99 g TN d^− 1 m^− 2) respectively, was more effective at pollutant removal than the other three units. There were no significant differences in TP removal between the aeration units and non-aeration units. Less surface area is needed due to high removal efficiency in APCW and the additional cost of operation is quite little. The results from this experiment indicated that limited artificial aeration in constructed wetlands is a cost-effective method for treating domestic wastewater.     

人工湿地处理高盐度污水的适用性及研究进展

人工湿地作为一种高效、低成本的新兴污水处理工艺,已被应用于各种类型污水的处理.作者概括了盐度对植物和微生物生理生化特性的影响,讨论了生物对高盐生境的适应性,指出通过种植耐盐植物,对微生物进行适度驯化培养后,利用人工湿地处理高盐度污水是完全可行的.最后介绍了国内外相关研究进展与应用现状.     

水平潜流人工湿地深度处理冷轧废水中试试验研究

针对冷轧废水深度处理后进一步回用的需求,采用中试人工湿地系统对二级处理后的冷轧废水进行深度再生处理,降低污染物浓度,使其回用于生产过程。试验结果表明:人工湿地系统对浊度、COD、TP、TN有良好的去除效果,出水满足钢铁企业回用水质要求。重点针对含氮污染物转化规律及去除机理进行分析,为提高人工湿地系统的脱氮效果提供依据。     

不同基质磷吸附性能及其在表流人工湿地中应用

选用煤渣和沙子两种基质进行等温吸附和吸附动力学试验,并结合表面流人工湿地处理含磷废水的效果,研究了煤渣和沙子对磷的吸附特性以及两种基质在表面流湿地中的除磷效果。结果表明:吸附实验中,Freundlich和Langmuir方程均能较好地拟合两种基质对磷的吸附特性,一级反应动力学方程能够很好拟合沙子的吸附动力学曲线,煤渣的动力学拟合情况较差。以煤渣为基质的表面流人工湿地对磷的平均去除率(35.79%)低于以沙子为基质的表面流人工湿地对磷的平均去除率(48.25%),并且沙子湿地除磷的稳定性好于煤渣湿地。     

模拟沸石垂直潜流人工湿地除磷性能试验

为确定沸石作为人工湿地基质的可行性,就沸石静态吸附和模拟沸石人工湿地去除生活污水中的总磷进行了试验。结果表明,温度降低时TP最大理论吸附量上升11.63%;最大TP解析量占最大吸附量的2.31%;本试验条件下,模拟沸石人工湿地对生活污水中TP的平均去除率为34.12%。就TP的去除而言,沸石不适合单独作为人工湿地基质,若采用应注意因TP解析而形成的二次污染。     

垂直流人工湿地净化生活污水的试验研究

通过试验考察垂直潜流人工湿地在不同的水力负荷、pH值、有机负荷下对生活污水的净化效果。试验结果表明,在较低水力负荷内,CODCr去除率都保持在70%以上。当水力负荷在0.15 m3/(m2.d)时,NH3-N的去除率在试验范围内最高为92%。垂直流湿地在pH值为8的运行条件下净化效果最佳,CODCr、NH3-N、TP的去除率分别为80%、84%、82%。有机负荷在22.5～45 g[CODCr]/(m2.d)时,CODCr去除率都能保持在80%以上。当有机负荷增加至52.5 g[CODCr]/(m2.d)时,CODCr和NH3-N的去除效果迅速降低。垂直流湿地系统适合的进水条件为水力负荷0.05～0.2 m3/(m2.d)、进水pH值为7～8、有机负荷为22.5～45g[CODCr]/(m2.d),此时对CODCr、NH3-N、TP均有比较好的去除效果。     

三种不同内部结构的潜流式人工湿地特性研究

对3种不同内部结构的潜流湿地的特性进行了研究.示踪试验的结果表明,3种湿地的HRT为:垂直折流湿地>水平折流湿地>常规湿地.在试验条件下,常规湿地对CODCr、NH4——N、TN、PO4-3-P的去除率分别为76.5%、56.6%、54.4%和93.1%;水平折流湿地相应的去除率分别为88.8%、72.6%、65.8%和96.9%;垂直折流湿地相应的去除率分别为94.1%、82.6%、79.2%和99.6%;对4种污染物的去除效果均为:垂直折流湿地>水平折流湿地>常规湿地.