滇池湖滨带人工湿地削减规律研究探讨

文章分析了滇池湖滨带人工湿地各级结构单元的水质指标数据,从pH、SS、BOD5、COD、TP、TN的污染消减规律入手,深入探讨了人工湿地对污染河水的净化效果。结果表明:人工湿地系统对TP、TN的消减效果最好;COD消减效果最差;湿地构造及植物群落影响人工湿地对污水的净化能力。     

厌氧段-人工湿地处理污水高效稳定机理研究

针对农村生活污水中悬浮物(SS)影响人工湿地运行稳定性问题,该研究在人工湿地前增加折流板厌氧池形成厌氧段-人工湿地污水处理系统.为期36个月的生产性试验研究结果表明,常温下厌氧段对SS的去除率约80%,整套系统对COD、TN、TP去除率分别为80.95%、85.12%、68.15%;低温下系统对COD、TN、TP去除率...     

新型人工湿地对工业区降雨径流的净化研究

根据东莞市同沙水库集水区内工业区降雨径流的水质、水量特征,采用新型折流式人工湿地对其进行模拟及实地降雨径流净化研究.对人工湿地不同运行阶段模拟降雨径流的净化效果进行对比,分析COD、SS、TN、TP、NH4+-N以及重金属Pb、Zn、Cu在湿地系统中的沿程变化,探讨它们的主要去除机制.模拟净化研究中,除TN外,湿地系统出水各污染物均达到《地表水环境质量标准》(GB 3838-2002)Ⅲ类质量标准,TN达Ⅳ类标准;且大部分污染物在湿地前端被去除.实地降雨径流净化研究中,COD、SS、TN、TP及NH4+-N的平均去除率分别为90.9%、97.0%、83.4%、92.2%、90.0%;重金属Pb、Zn、Cu的平均去除率分别为98.4%、94.1%、93.6%,出水均能达地表Ⅲ类水标准.研究表明,折流式人工湿地系统对工业区降雨径流的净化效果显著,湿地系统具有较强抗冲击负荷能力.另外,小幅温度变化对湿地系统中污染物的去除影响不大.     

人工湿地对化粪池出水净化效果的对比研究

对比了四种复合人工湿地系统对化粪池出水COD、TP、NH3-N和SS的净化效果,试验系统均采用间歇式进水,时间间隔为1d。为期7个月的运行结果表明,系统出水水质均达到城镇污水处理厂污染物排放标准(GB18918-2002)中的二级标准,其中潜流(水平流)+垂直流(上行流)湿地系统对COD的去除效果最好;垂直流(下行流)+垂直流(上行流)湿地系统对TP、NH3-N、SS去除效果最好;选用含钙石灰石和含铁矿粉做填料、采用间歇式的运行方式可以提高湿地系统对污染物的去除率。     

一种多介质层波形潜流人工湿地处理重污染河水试验

我国河流污染严重,城市黑臭水体的比率日益增加。人工湿地作为一种高效低耗能的绿色处理技术,已被广泛应用于污染河水的治理。通过对比分析分层装填复合填料的多介质层波形潜流人工湿地和单一砾石填料的普通人工湿地处理重污染河水的效果,研究了特种基质填料强化脱氮除磷作用以及不同水力负荷条件的影响。试验结果表明:在水力负荷为0.2 m~3/(m~2·d)时,普通湿地对COD、NH3-N、TN和TP的去除率分别达到55.95%、77.85%、39.80%和54.94%;多介质层湿地对COD、NH3-N、TN和TP的去除率分别达到58.52%、75.99%、67.08%和57.31%。在水力负荷为0.5 m~3/(m~2·d)时,普通湿地对COD、NH3-N、TN和TP的去除率分别达到68.46%、90.73%、42.13%和53.70%;多介质层湿地对COD、NH3-N、TN和TP的去除率分别达到69.61%、89.94%、77.58%和68.63%,其脱氮效果明显好于普通湿地。以复合填料包分层装填的波形潜流人工湿地系统具有良好的脱氮除磷效果,有很好的推广应用价值。     

用于人工湿地强化预处理的气浮加药研究

针对天津某人工湿地工艺研发了由溶气气浮设备和生物滤池组成的人工湿地预处理工艺。对生物滤池开展了稳定运行、反冲洗研究,并对生物滤池中的微生物进行分析;对河道水体中SS、COD、TN、TP去除效果进行试验,得出结论:当PAC和PAM投加量分别为30,1.5 mg/L时,出水中的COD、SS、TN和TP水质指标均符合《城镇污水处理厂污染物排放》一级A标准。     

人工湿地在工业园区污水厂尾水处理中的工程应用

针对工业园区污水处理厂出水中有机污染物、氮、磷等超标问题,采用"水平潜流+表面流"复合人工湿地工艺,对污水处理厂尾水进行深度净化。运行结果表明:湿地系统净化效果良好,运行稳定,对SS、COD、BOD5、TN、NO-3-N、NH3-N和TP平均去除率分别为58.3%、35.7%、47.4%、52.8%、65.4%、52.6%和53.6%,出水水质指标(除SS外)达到GB 18918—2002《城镇污水处理厂污染物排放标准》一级A标准。该工程具有显著的生态效益和社会效益。     

不同修复模式下湿地水质变化的短期效应分析

为探讨不同修复模式对水质的影响,从2009-03-2010-03跟踪监测了精养鱼塘、人工修复水域以及自然修复区3种不同水环境的NO3^--N、NH₄^--N,Chl a、DO、EC、TP、TN和COD等指标,从空间和时间的角度分析了人工修复和自然修复对水质的影响情况。结果表明:在修复研究期间,与精养鱼塘相比,人工修复区水体中TN、NO3^--N、TP、Chl a、COD等指标经过修复中期的短暂上升后均有显著下降（P<0.05）,水质有显著改善;自然修复区水质中TP、Chl a、COD等指标均有下降,而TN呈现显著上升（P<0.05）,水质总体有小幅改善趋势。在适当的人为干扰下,人工修复区能够在短期内对水质产生显著的改善效果。因此,积极且适当的人为干扰的湿地修复比自然恢复对水质的改良效果更加显著。     

人工湿地与臭氧联合处理技术用于以再生水为补水水源的景观湖净化

采用人工湿地与臭氧联合处理技术,深度净化以污水厂尾水为再生水的补水水源,及对景观湖水进行循环净化,保证景观湖水质和水量。介绍了系统的工艺设计,并对运行后的水质进行检测分析。人工湿地系统以净化后污水厂尾水作为景观湖补水,水力负荷为0.268 m~3/(m~2·d)时,COD和BOD_5去除率可达60%以上,氨氮和TN去除率达80%以上,TP去除率达70%。人工湿地用于湖水循环净化,水力负荷为1.07 m~3/(m~2·d)时,人工湿地对污染物的总去除率为40%~50%。为防止湖水富营养化,阶段性启动臭氧系统进行湖水脱色、除臭处理,当臭氧投加量为3 mg/L时,对色度去除率可达80%,对氨氮去除率可达40%以上。     

大型表流人工湿地不同季节不同进水负荷下水质净化效果研究

以盐城市饮用水源生态净化工程(盐龙湖工程)为研究对象,探究了该工程表流人工湿地在不同季节不同进水工况下对微污染水的水质净化效果。结果表明:盐龙湖表流人工湿地对微污染水体具有较好的净化效果,对TP、TN、NH3-N和SS的平均去除率分别为25.8%、23.7%、32.1%和38.3%;TP、TN、和SS四季的平均去除率均表现为夏季秋季春季冬季,NH3-N四季的平均去除率表现为秋季夏季春季冬季;TN和NH3-N在一年四季中各进水工况下的去除率均表现为随着进水量的增大而减小;TP和SS在夏、秋季节的去除率随进水量的增大表现为先上升达峰值后下降的趋势,春季和冬季的去除率同样表现为随着进水量的增大而减小。     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.     

Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.