水力停留时间对活性炭生物转盘处理污染河水的影响

将生物转盘与活性炭网状填料相结合,进行活性炭吸附实验并采用河水直接挂膜,探究在盘片最佳转速下,不同水力停留时间对活性炭生物转盘去除NH_4~+-N、TP、高锰酸盐指数以及生物膜特性的影响.结果表明,Freundlich等温线显示活性炭对水中NH_4~+-N、TP、高锰酸盐指数有较好的吸附性能.盘片转速为3 r·min-1时,NH_4~+-N、TP、高锰酸盐指数去除率分别为86.05%、81.28%、77.09%,去除性能最佳.水力停留时间对去除NH_4~+-N、TP存在显著线性相关(R20.9)且去除率存在显著差异(P0.05),而对高锰酸盐指数不存在显著线性相关且去除率差异不显著(P0.05).HRT对生物膜活性、蛋白多糖以及S-EPS、LB-EPS、TB-EPS三维荧光峰均有影响.     

滤料对生物滤池启动及污水处理的影响

该文以农村生活污水为研究对象,设计了一种生物滤池污水处理工艺,选择陶粒、弹性材料和聚丙烯球为滤料,活性污泥辅助挂膜,考察不同滤料的挂膜及污水处理效果。结果表明,陶粒滤料表面附着的生物膜量在28 d进入了稳定期,达26.88 mg/g,而弹性滤料和聚丙烯球分别需32 d和34 d,其膜量为19.62 mg/g和16.78 mg/g,且陶粒生物滤池的COD和NH_4~+-N去除率在第28天趋于稳定,膜生物量最大。陶粒滤料在供试的生活污水中COD去除率可以达到96.3%,出水水质达到国家污水综合排放一级标准;TP去除率达到63.46%,NH_4~+-N去除率达到82.9%,出水水质达到国家污水综合排放二级标准;TN去除率可以达到67.6%,出水水质达到国家污水综合排放一级标准。陶粒滤料在低、中、高污染负荷条件下,均有较好的碳、氮、磷处理效果,中污染负荷时去除率更高,COD、TP、NH_4~+-N和TN去除率达96.9%、64.2%、82.2%和68.9%。在C/N比为5∶1、10∶1、15∶1条件下,陶粒滤料均有较好的碳、氮、磷处理效果,C/N为10∶1时去除率更高,COD、TP、NH_4~+-N和TN的去除率达95.6%、64.7%、81.3%和67.9%;陶粒滤料在8、18、28℃条件下,均有较好的碳、氮、磷处理效果,温度为28℃时去除率更高,COD、TP、NH_4~+-N和TN的去除率达96.1%、63.9%、81.6%和68.5%。     

新型SBR脱氮除磷试验研究

为了提高SBR工艺脱氮除磷的效率,依据传统SBR工艺(序批式活性污泥法)在反应器装置进行改造优化,在反应器装置中应用生物膜的原理安装小型生物转盘,在人为时间控制与配置下处理污水。研究表明,新型SBR工艺TP、NH_4~+-N进水浓度分别为4 mg/L~6mg/L、13mg/L~16mg/L,出水浓度分别0.6 mg/L~0.9mg/L、1.5mg/L~2mg/L对TP、NH_4~+-N平均去除率约为91%、92%,出水水质指标完全达到城镇污水排放一级A(GB18918-2002)。新型SBR工艺装置简单、占地面积小、处理效果好等优点,小型生物转盘管理维护简单,适用处理低浓度的生活污水,是值得广泛推广的一项新型工艺。     

循环水养殖系统中自然微生物生物膜形成过程实验

进行了不同初始NH4-N浓度,在实验水温20～24℃条件下,利用微生态制剂辅助,循环水养殖系统中自然微生物生物膜形成过程的实验研究。结果表明:不同NH4-N浓度对自然微生物生物膜形成产生显著影响,5、10和20 mg/L高浓度NH4-N更易于微生物的扩繁生长和生物膜形成,其生物膜达到预期水质净化效果的形成周期,即生物挂膜成熟周期,约需要35～40 d。生物挂膜成功后,形成很好的硝化作用,实验生物滤池中的NH4-N、NO2-N浓度均保持低于0.05 mg/L,COD浓度低于3 mg/L,显示出对NH4-N、NO2-N和COD很高的去处效果,但对PO4-P处理效果不明显。而1和2 mg/L低浓度NH4-N不易于微生物的扩繁生长,难以形成具有较好水质净化效果的生物膜,即生物挂膜难以成功。     

用于流化床反应器的生物膜载体的比较研究

分别采用活性炭、橡胶和轻质陶粒作为生物膜载体,用流化床生物反应器进行废水处理的实验,比较3种载体材料的挂膜特性、耐磨性,并比较了对废水COD和NH3-N的去除效果。从实验中发现,活性炭具有吸附力强、比重小、挂膜时间比较短等特点,但耐磨性较差;橡胶载体具有比重较小,动力消耗较小的特点,但生物膜挂膜时间较长;陶粒比重适中,较其它两者偏大,挂膜时间最短,耐磨性能比活性炭要好,具有较强的实用价值和很大的研究潜力。     

生物炭载体的表面特征和挂膜性能研究

以花生壳为原料,于300~700℃下热解制备生物炭以作为生物膜载体,对其进行了理化性质表征和挂膜试验.结果表明:较高的热解温度(700℃)能促进生物炭载体孔隙结构发展,生物炭表面ζ电位上升,亲水性增加,从而有利于污水微生物的附着和生长. 挂膜期间,生物炭载体单位挂膜量分别高出陶粒44%~84%,高温(700℃)生物炭载体生物膜对NH4+-N的去除率高出陶粒1%~3%,而中低温(300、500℃)生物炭载体生物膜对NH4+-N的去除率较陶粒低5%~10%,显示生物炭表面理化性质可能对附着的生物膜微生物种类和活性产生影响.     

以亲水化改性聚氨酯为多孔载体的生物膜移动床反应器处理污水中试研究

载体是生物膜移动术反应器(MBBR)工艺的关键影响因素,利用亲水化改性聚氨酯载体构建MBBR,用于城市污水的中试研究.反应器日处理能力为3～3.5 t.d-1,水力停留时间为7～8 h,在连续进水(进水COD 140～280 mg.L-1,NH4+-N 30～50 mg.L-1,总氮45～65 mg.L-1,总磷2.5～4.0 mg.L-1)条件下对改性载体的挂膜速度、有机物和氮的去除效果及不同温度下的污水处理特性进行了研究.140 d的试验结果表明在24～28℃时,载体上生物膜在6 d左右即可完成挂膜,并达到稳定的处理效果.COD、NH4+-N、TN和TP的平均去除率分别为70%、97%、70%和39%.随着水温逐渐降低到12℃左右,NH4+-N的去除率依然能达到97%,表明通过添加改性载体可以提高反应器低温条件下的硝化能力.     

磁性载体生物膜反应器处理生活污水的试验研究

选取天然多孔矿物-浮石、网络状塑料外壳、磁铁为材料,开发出一种新型磁性载体,并将该载体应用于生物膜反应器中进行废水处理试验,结果表明:该磁性载体生物膜反应器在载体的挂膜性能及主要污染物去除功能上均优于非磁性载体生物膜反应器.磁性载体可在5d内完成挂膜,而非磁性载体则需8d,磁性载体生物膜反应器对COD、NH+ 4-N的去除率比非载体生物膜反应器分别高出5%和20%左右.在载体中心磁场强度为200Gs,水中溶解氧DO为2.0~3.5mg/L,水力停留时间HRT为5h的条件下,校园生活污水经磁性载体生物膜反应器处理后,出水中COD稳定在20mg/L左右, NH4+-N在5mg/L以下,两者的去除率均在90%左右,出水总氮为15mg/L,去除率在50%以上.实验结果还表明:连续运行60d后,磁性载体反应器内的生物膜量和悬浮污泥量仅为非磁性载体反应器的70%,说明磁场的存在有利于污泥减量化.磁载体生物膜反应器中载体外表面附着污泥及生物膜的SOUR值均大于非磁载体生物膜反应器,表明一定的磁场强度可以提高微生物活性.     

膜生物反应器处理校园废水的研究

使用膜生物反应器处理人工校园废水,探讨了反应器内污泥分别为颗粒污泥和絮状污泥时COD、NH_3-N、TP的去除效率。结果表明颗粒污泥膜反应器COD、NH_3-N、TP的平均去除率分别为95.79%、93.58%、83.09%,均好于絮状污泥膜反应器内的82.7%、83.45%、62.52%。     

进水有机负荷对三级生物滴滤池脱氮除磷的影响

试验采用三级(好氧/兼氧/好氧)多层组合填料生物滴滤池处理模拟生活污水,探索强化脱氮除磷工艺。考察了在相同水力负荷和布水周期下,改变进水有机负荷对COD、NH_4~+-N、TN和TP去除率的影响,并用扫描电镜和X射线衍射(XRD)对填料进行辅助分析。研究结果表明,三级串联生物滴滤池的组合相比传统的单级或两级生物滴滤池反应器处理效果更好。第1级和第2级生物滴滤池去除COD、NH_4~+-N和TN效果较好,贡献率合计分别为93.0%、91.2%和91.4%。第1级和第3级生物滴滤池除磷效果较好,贡献率合计91.4%。有机负荷为0.328~0.392 kg/(m~3·d)时,系统总体去除效果最好。     

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.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

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.     

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

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