梯田式人工湿地处理生活污水的初步研究

针对山丘坡地的自然环境特点,提出构建梯田式人工湿地处理生活污水的方法,并通过实验装置对梯田式人工湿地处理生活污水的效果进行了初步研究。结果表明:当CODCr、NH4+-N、TP的进水质量浓度变化范围在182.3~286.7 mg/L、32.91~59.28 mg/L、1.23~3.05 mg/L时,其平均去除率分别为86.52%、80.5%、96.16%,出水质量浓度分别低于30mg/L、10mg/L、0.1mg/L;湿地基质中硝化菌、反硝化菌数量变化范围分别为1.5万~420万MPN/g、30万~1 860万MPN/g。与常规人工湿地相比,梯田式人工湿地具有较强的污染物去除能力,特别是具有高效的脱氮除磷效果。     

人工湿地对化粪池出水净化效果的研究

通过在同种基质上种植相同数目的芦苇,研究了垂直流人工湿地对化粪池出水的净化效果以及不同水力停留时间对污水净化效果的影响。结果表明,同种填料、不同水力停留时间对污水中TP、NH3-N、COD的净化效果不同。由于芦苇根系和微生物的吸收与分解作用以及基质的吸附作用,种植芦苇的人工湿地的出水水质要比没种芦苇的好。     

人工湿地净化污水机理研究进展

人工湿地是一种新型的污水处理技术，它具有处理效率高、效果好、投入少、维持费用低等特点。重点阐述人工湿地净化污水的机理，提出了人工湿地技术未来的研究方向，并对其应用前景进行了展望。     

温度和基质对人工湿地脱氮除磷效果的影响

构建由潜流人工湿地和表流人工湿地串联而成的复合人工湿地系统,研究了复合人工湿地脱氮除磷效果以及温度和基质对人工湿地脱氮除磷效果的影响。结果表明,复合人工湿地TP、氨氮平均去除率为33.64%、57.24%;水温降低会导致人工湿地氮磷去除率下降;基质为粗砂的潜流人工湿地脱氮除磷能力大于基质为砾石的潜流人工湿地。     

水平潜流人工湿地脱氮除磷研究进展

总结了水平潜流人工湿地的脱氮除磷机理,分析了进水水质、植物、基质、温度和水力停留时间这5种影响处理效果的主要因素,从不同角度论述了提高脱氮除磷效果所采取的措施,并探讨了水平潜流人工湿地存在的局限性和发展趋势。     

添加N、P后复合型人工湿地系统的脱氮除磷效果研究

文中介绍了采用向复合型人工湿地系统中添加氮、磷等营养物质,提升湿地系统的污染负荷,研究湿地系统4级组成湿地的脱氮除磷效果。结果表明,在湿地系统总氮、总磷进水浓度提升至4．02mg·L^-1、0．41mg·L^-1,经湿地系统运行52hr后分别下降至1．68mg·L^-1、0．16mg·L^-1,湿地系统对总氮、磷的总去除率分别为58．0％、61．0％。4级不同湿地的脱氮除磷能力不同。二级表面流湿地对总氮的去除贡献最大,一级水平流潜流湿地对总磷的去除贡献最大。湿地系统的脱氮除磷效果与湿地进水污染负荷成正相关．湿地系统进水的污染负荷是影响湿地系统脱氮除磷效率的主要因素。     

不同植物配置人工湿地冬季生活污水净化效果比较

以某三级串联水平潜流人工湿地污水处理工程为实验基地,研究了5种华南地区常见湿地植物的选择和配置对净化冬季生活污水的影响,为华南地区人工湿地合理优化配置植物提供一定的依据。结果表明:人工湿地系统在冬季对COD、BOD5、TP和大肠菌群仍有较好的去除效果,对TN的去除效果较差。在实验条件下,COD和BOD5的降解主要发生在第一级湿地单元,TP和TN的降解主要发生在第三级湿地单元。三级串联湿地系统净化效果较佳的植物搭配是:第一级栽种水生美人蕉,第二级栽种再力花,第三级栽种菖蒲。     

生物接触氧化法-人工湿地处理常低温生活污水

采用生物接触氧化法(BCO)-人工湿地组合工艺处理常低温生活污水,当BCO的气水比为7∶1、回流比为100%、人工湿地的水力停留时间(HRT)为9 h,人工湿地的水力负荷(HLR)为3. 65 m3/(m2/d)时,在常温下(22~27℃),组合工艺出水COD、NH_4~+—N、TN和PO_4~(3-)—P分别为14. 60、1. 40、12. 70和0. 43 mg/L,出水满足《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级A标准;而低温下(7~12℃),组合工艺出水COD、NH_4~+—N、TN和PO_4~(3-)—P分别为29. 60、9. 90、19. 90和0. 88 mg/L。保持气水比和回流比不变,控制低温下BCO的HRT为12 h,人工湿地的HLR为2. 74 m3/(m2/d)时,组合工艺出水COD、NH_4~+—N、TN和PO_4~(3-)—P为18. 40、6. 17、14. 17和0. 66 mg/L,去除率分别为90. 60%、87. 80%、75. 40%和85. 30%。结果表明:常、低温下该组合工艺均能够实现污染物的良好去除,为实际工程应用提供参考。     

人工湿地生态系统脱氮除磷机理及研究进展

介绍了人工湿地生态系统去除污水中氮磷的机理,并从工艺优化、湿地植物、基质和微生物四个方面系统地阐述了目前人工湿地系统提高氮磷去除率的研究进展情况;通过优化湿地系统设计、湿地植物的筛选、基质的选择和复合、微生物种群的调控等可以有效提高人工湿地的氮磷去除率,提出了当前人工湿地研究中存在的问题和研究方向.     

堵塞对湿地内水流流态及污水处理效果的影响

通过在污水中加入氯化钠示踪剂,研究人工湿地及其对照系统内水力停留时间的分布(HRTD),探讨潜流人工湿地和垂直流人工湿地中植物在堵塞前后对水流流态的影响,探讨堵塞对上述两种人工湿地水流流态的影响。结果表明:对于潜流人工湿地(SFCW),堵塞前湿地植物缩短了水力停留时间(HRT),堵塞后延长了HRT;对于垂直流人工湿地(VFCW),堵塞前湿地植物对水流流态无明显影响,堵塞后延长了湿地内的HRT。堵塞对湿地内水流流态影响明显,潜流和垂直流湿地由于堵塞其HRT分别延长了12.3%,22.6%。堵塞后湿地对污水的净化能力都要强于堵塞前,但是湿地的污水处理量减小,堵塞严重时湿地丧失其污水净化功能。     

人工湿地深度处理医院污水的研究

以人工湿地系统处理医院污水处理站二级处理出水,以达到深度降解并去除TN的目的。设计总面积782 m2人工湿地系统,其中自由表面流型(FWS)人工湿地450 m2和潜流型(SSF)人工湿地186 m2,最后连接生态景观池面积146 m2,每日平均抽取30 m3污水(二级处理出水),水力负荷为0.05 m/d。早期运行结果显示,TN去除率为44%,NO3-—N去除率FWS湿地为15%,SSF湿地为34%。试验进行到稳定运行期,调高流量至70～100 m3/d,水力负荷为0.11～0.16 m/d,结果显示,NO3-—N去除率达68%;比较FWS与SSF湿地的NO3-—N的去除速率,FWS湿地为2.48 g/(m2.d),SSF湿地为3.61 g/(m2.d)。SSF湿地对NO3-—N的去除效能比FWS湿地好。     

潜流人工湿地处理城市污水氮和有机物的研究

在自行建造的模拟人工湿地装置上,通过改变水位来控制小型潜流人工湿地DO浓度,从而提高处理效率。试验中两种水位变化的运行都降低了人工湿地的氮和有机物,特别是对氮有较好的去除效果。第1阶段水位小幅度变化,出水DO浓度主要在2～4mg/L之间,COD、BOD5、TN、TKN去除率分别在85%～93%,91%～95%,65%～75%和75%～85%之间;第2阶段水位大幅度变化,出水DO浓度主要在1～4mg/L之间,COD、BOD5、TN、TKN去除率分别在80%～88%,85%～90%,70%～80%和80%～90%之间。     

Domestic wastewater treatment by a constructed wetland system planted with rice

The experiments were conducted in four concrete laboratory scale free water surface constructed wetland units 1 m wide, 1.5 m long and 0.8 m deep. Paddy field soil was added to a depth of 0.4 m and rice seedlings (Oryza sativa L.) were transplanted into the units at a density of 25 plants/m(2). Domestic wastewater collected from Chiang Mai University was applied into each unit via two different modes to evaluate suitable conditions for wastewater treatment and rice yield. In the first experiment, the wastewater was fed intermittently (7 h/day) with a hydraulic loading rate of 2, 4, 6 and 8 cm/day. The maximum removal efficiencies for chemical oxygen demand, biological oxygen demand, total kjedahl nitrogen and suspended solids were only 49.1, 58.7, 64.0 and 59.4%, respectively, due to the short hydraulic retention time for the biodegradation of organic substances. In the second experiment, the wastewater in each unit was inundated to a depth of 15 cm for 10, 15, 20 and 25 days in each unit and then drained and re-flooded. Removal efficiencies of chemical oxygen demand, biological oxygen demand, total kjedahl nitrogen and suspended solids were greater than in the first experiment especially at the 25 day retention time and except for suspended solids met the Thai national effluent standard. The study revealed that apart from wastewater treatment, wastewater can replace natural water to grow rice in the dry season or throughout the year. Moreover, nutrients in wastewater can be a substitute for chemical fertilizers. Rice grain production was 4,700 kg/ha and only 6% less than the production from the conventional paddy field.     

一体化装置-潜流人工湿地处理生活污水的研究

采用一体化装置—潜流人工湿地工艺对生活污水的处理进行了研究。结果表明,一体化装置对CODCr、BOD5、氨氮及SS的去除率分别在60.68%、58.87%、63.69%和75.51%以上,人工湿地对CODCr、BOD5、氨氮及SS的去除率分别在49.97%、84.40%、70.77%和82.74%以上,该工艺对各污染物去除效果明显,具有工艺流程简单、运行费用低等特点。     

Treatment of high strength wastewater with vertical flow constructed wetland filters.

The aim of the present study was to evaluate the behaviour of vertical flow constructed wetlands to treat high strength wastewater. Influents were obtained mixing tap water with different percentages of MSW landfill leachate (5%, 10% and 20%). Phragmites australis seedlings were used as macrophytes. The reeds were nurtured during three spring months, before the start of the experimental period. Three and four days of detention time were adopted. Influent concentrations of 510-2,050 mg L(-1), 180-740 mg L(-1) and 65-260 mg L(-1) were obtained for COD, N-NH4(+) and N-NO3(-), respectively. The environmental temperature averaged around 31.0 +/- 1.4 degrees C. During the experimental period, all parameters showed an increasing removal efficiency trend. Best results in terms of COD removal were obtained for mixtures at lowest rate of landfill leachate; while, denitrification process showed an opposite behaviour; finally, the removal of ammonia nitrogen appeared to be independent upon influent concentrations. Analysis carried out on the reed tissues showed a theoretic maximum storage of TKN in the leaves of about 55 mg/g dry weight. A leachate percentage of about 35% was derived to be able to fully inhibit the growth of macrophytes.     

Phosphorus mass balance in a surface flow constructed wetland receiving piggery wastewater effluent

This research was conducted to investigate the phosphorus forms present in water, soil and sediment and to estimate the phosphorus mass balance in a surface flow constructed wetland (CW). Water quality and sediment samples were collected from each cell along the hydrologic path in the CW from October 2008 to December 2010. At the same time, three dominant plant species (e.g. common reed and cattails) were observed through the measurement of the weight, height and phosphorus content. Based on the results, the orthophosphate constituted 24-34% of total phosphorus in water for each cell. The overall average phosphorus removal efficiency of the CW was approximately 38%. The average inflow and outflow phosphorus loads during the monitoring period were 1,167 kg/yr and 408 kg/yr, respectively. The average phosphorus retention rate was 65%, was mainly contributed by the settling of TP into the bottom sediments (30%). The phosphorus uptake of plants was less than 1%. The estimated phosphorus mass balance was effective in predicting the phosphorus retention and release in the CW treating wastewater. Continuous monitoring is underway to support further assessment of the CW system and design.     

Vertical flow constructed wetland for textile effluent treatment.

A pulse feed vertical flow constructed wetland (VFCW) proved to be efficient in the treatment of a textile effluent being able to buffer, dilute and treat an Acid Orange (AO7) accidental discharge. The influence of the flooding level (FL) and pulse feed (PF) duration on the removal efficiencies of a VFCW was examined. Average AO7 removal efficiencies of 70% were achieved for an AO7 Inlet concentration of 700 mgl(-1) applied during 15 min cycle(-1) (every three hours) at a hydraulic load of 13 lm(-2) cycle(-1) and an FL of 21%. The VFCW was modelled by analogy with a combination of ideal reactors. The simplest combination that best reproduced the experimental results was an association of 2 reactors in series plus 1 reactor accounting the dead volumes. The model parameters helped to understand the hydrological and kinetic processes occurring in VFCW. Through the model simulation it was shown that 3 VFCW in series were enough to efficiently treat an organic mass load of 76 gAO7 m(-2) day(-1) in 9 hours and fulfil the discharge legislation. In this work it was possible to establish that the overall degradation kinetics was of first order.     

Use of headspace solid-phase microextraction to characterize odour compounds in subsurface flow constructed wetland for wastewater treatment.

A headspace solid-phase microextraction (HS-SPME) preconcentration method was applied to the analysis of some of the major odorous compounds occurring in wastewater using GC/MS or GC/NPD detection. The detection limit for volatile amines, volatile fatty acids, and volatile alkylsulphides ranged from 3 to 100, 2 to 150, and 0.0006 to 0.035 microg/L, respectively. The SPME method was used to examine the fate of odorous compounds in the subsurface flow constructed wetlands (SFCW) operated under different hydraulic loading rate (HLR), bed aspect ratio, and granular medium size. Among the experimental conditions evaluated in the SFCW beds, HLR was found to be the most important factor influencing the evolution of the studied compounds. There were also significant differences among bed types in the behaviour of ammonia (NH3), acetic acid (Ac), isovaleric acid (IsoA), propionic acid (PrA), and dimethylsulphide. Aspect ratio and medium granular size were minor factors influencing SFCW performance. The major odour compounds by mass in the effluent of SFCW with different operational conditions were NH3 and Ac. Further removal of these two compounds is considered as very important from the viewpoint of chemical composition. On the other hand, Relative Odour Intensity (ROI: ratio between the absolute concentration to the odour threshold concentration) suggested that PrA and IsoA were the two major compounds responsible for odour intensity. Thus, further removal of these two compounds is viewed as very important for the effluent deodorization, especially for PrA. From our results, this compound appears to be produced by processes occurring in the SFCW.     

Nitrogen removal and ammonia-oxidising bacteria in a vertical flow constructed wetland treating inorganic wastewater

Nitrogen removal performance and the ammonia-oxidising bacterial (AOB) community were assessed in the batch loaded 1.3 ha saturated surface vertical flow wetland at CSBP Ltd, a fertiliser and chemical manufacturer located in Kwinana, Western Australia. From September 2008 to October 2009 water quality was monitored and sediment samples collected for bacterial analyses. During the period of study the wetland received an average inflow of 1,109 m3/day with NH3-N = 40 mg/L and NO3-N = 23 mg/L. Effluent NH3-N and NO3-N were on average 31 and 25 mg/L, respectively. The overall NH3-N removal rate for the period was 1.2 g/m2/day indicating the nitrifying capacity of the wetland. The structure of the AOB community was analysed using group specific primers for the ammonia monooxygenase gene (amoA) by terminal restriction fragment length polymorphism and by clone libraries to identify key members. The majority of sequences obtained were most similar to Nitrosomonas sp. while Nitrosospira sp. was less frequent. Another two vertical flow wetlands, 0.8 ha each, were commissioned at CSBP in July 2009, since then the wetland in this study has received nitrified effluent from these two new cells.