微生物修复辽东湾油污染湿地研究

通过向受污湿地土样中添加菌株,探讨微生物对石油烃的降解.实验发现,混合菌能够充分发挥各菌种之间的协同作用,比单菌降解更为有效.最适降解条件控制在pH8.0,温度25℃.适宜的表面活性剂对微生物繁殖进而对油降解具有促进作用,加入300mg·kg^-1TW-80降解8d后,菌落数增加了6.22倍,油的降解率提高了20.1%.适量的H₂O₂有助于细菌分解油,过量会造成菌株死亡,每次添加计量控制在400mg·L^-1为宜.经过11d,H₂O₂累计量达到7000mg·L^-1,土样中油的降解率由39.81%提高到66.79%.     

甲苯、邻二甲苯和二氯甲烷混合气体降解菌群构建及其性能研究

挥发性有机物（VOCs）排放导致一系列环境问题,而生物法是一项绿色处理技术.本实验选取3种VOCs（甲苯、邻二甲苯、二氯甲烷）作为模型污染物,利用甲苯、邻二甲苯降解菌Zoogloea resiniphila HJ1（菌株HJ1）及二氯甲烷降解菌Methylobacterium rhodesianum H13（菌株H13）构建复合菌株,采用“专属菌+综合菌”模式以复合菌株和驯化污泥构建复合强化菌群.研究表明,复合菌株可完全降解400 mg·L^-1甲苯、256 mg·L^-1邻二甲苯、200 mg·L^-1二氯甲烷,矿化率分别为74.3%、61.1%、82.7%.复合菌株可完全降解480 mg·L^-1混合污染物（3种污染物浓度比为1∶1∶1）,降解速率依次为甲苯>邻二甲苯>二氯甲烷.经过优化,菌株HJ1和菌株H13最佳配比被确定为1∶5.复合强化菌群不仅大幅提高了 邻二甲苯、二氯甲烷降解速率,还提高了混合污染物矿化率.甲苯、邻二甲苯的存在对二氯甲烷降解产生明显抑制效应,而低浓度二氯甲烷 （< 240 mg·L^-1）对甲苯、邻二甲苯降解无明显抑制作用.本研究为VOCs生物净化过程中菌群构建提供数据支撑.     

DO浓度对生活污水硝化过程中N2Ｏ产生量的影响

为确定污水脱氮过程中最优的DO浓度和曝气方式,以提高污水处理效率,降低N₂Ｏ产生量,采用实际生活污水应用小试SBR反应器,重点考察了不同DO浓度条件下,硝化效率和硝化过程中N₂Ｏ的产生量.结果表明,当DO浓度恒定为0.4 mg·L^-1时,虽然硝化过程所消耗的能量最低,但其氨氮氧化的速率较低.提高DO浓度,氨氮氧化速率可随之升高.低氨氮生活污水硝化过程中仍有N₂Ｏ产生.DO浓度为0.4 mg·L^-1 和0.9 mg·L^-1时,污水N₂Ｏ产生量(以N计)分别为1.5 mg·L^-1和1.6 mg·L^-1;而DO浓度为1.5 mg·L^-1和2.0 mg·L^-1时,N₂Ｏ产生量则分别降低至0.5 mg·L^-1和0.4 mg·L^-1.当DO浓度高于1.5 mg·L^-1后,继续提高DO浓度,氨氮氧化速率升高的速率变缓,同时N₂Ｏ产生量大幅降低.因此,从提高污水脱氮效率节能降耗和控制N₂Ｏ产生量2个角度考虑,生活污水脱氮过程中控制DO浓度在1.5 mg·L^-1较为适宜.     

渠式生物接触氧化法处理城市生活污水

河涌是广州的重要水系.但由于城市的发展和污水处理的滞后,导致广州的所有河涌都受到严重的污染.用渠式生物接触氧化反应器动态模拟河涌,对污水进行涌内处理的研究表明,距离长、截面大和逗留时间长的河涌进行构筑,悬挂填料和污水曝气处理,可以有效地处理城市污水.连续运行3个月,进水COD_Cr浓度180mg·L^-1～450mg·L^-1范围,COD_Cr和BOD₅的平均去除率分别为88%、95%.对氨氮和有机磷也有一定去除,进水总氮和总磷浓度分别为15mg·L^-1～30mg·L^-1和2.6mg·L^-1～4.1mg·L^-1时,平均去除率可分别达到52%和1%.     

UV/O3对亚硝基二甲胺降解产物的控制研究

对UV/O₃和UV/H₂Ｏ₂ 2种高级氧化工艺降解水中亚硝基二甲胺（NDMA）和控制二甲胺（DMA）生成的能力进行了比较研究.结果表明,UV/H₂Ｏ₂能够有效降解NDMA,但不能控制NDMA降解产物DMA的生成;UV/O₃高级氧化技术不仅能够有效地去除NDMA,同时对DMA的生成量也有很好的控制作用.进一步考察了不同臭氧浓度、溶液pH值以及NDMA初始浓度对UV/O₃工艺控制DMA生成量的影响.结果表明,臭氧浓度对UV/O₃控制DMA的生成有一定的影响,DMA的生成量随着臭氧浓度的增大而减小,臭氧浓度为6.64 mg·L^-1时,降解7.7 mg·L^-1 NDMA生成DMA的量为0.98 mg·L^-1.溶液pH值对UV/O₃控制DMA的影响较大,酸性和中性pH条件下,DMA的生成量随着pH的增大略有增加;碱性pH条件下,DMA的生成量明显减小,pH=11.0时降解初始浓度为7.7 mg·L^-1 的NDMA,DMA的生成量仅为0.3 mg·L^-1.NDMA的初始浓度对UV/O₃控制DMA的生成也有影响,NDMA初始浓度较小时,UV/O₃对DMA生成的控制更为明显.     

久效磷降解菌的分离及其酶促降解特性研究

从某农药厂废水处理池的污泥中分离到1株久效磷高效降解菌株M-1,经过对其形态特征、生理生化、以及16S rDNA序列分析,该菌株初步鉴定为Paracoccus sp..M-1能以久效磷作为唯一碳源生长,24 h对100 mg·L^-1久效磷的降解效率为92.47%.久效磷降解酶定域表达试验表明该酶为胞内酶,组成表达.久效磷酶促降解的最适反应pH为8.0,最适反应温度为25 ℃;其米氏常数（K_m）为0.29 μmol·mL^-1,最大降解速率(V_max)为682.12 μmol·(min·mg)^-1.久效磷降解酶热稳定性差,碱性条件下能够保持较高降解活性.     

颗粒污泥厌氧氨氧化动力学特性及微量NO2的影响

采用批试验方法,研究了颗粒污泥厌氧氨氧化动力学特性及微量NO₂的影响.用Haldane模型描述厌氧氨氧化反应动力学,得到最大氨氮反应速率6.65×10^-3 mg·(mg·h)^-1、氨氮半饱和常数87.1 mg·L^-1和抑制常数1 123 mg·L^-1,亚硝态氮半饱和常数15.39 mg·L^-1和抑制常数159.5 mg·L^-1.微量NO₂对厌氧氨氧化具有强化作用,基于Haldane模型建立了厌氧氨氧化的NO₂强化函数,估计了强化函数中的最大强化系数48.79、NO₂半饱和常数2 480 mg·m^-3、NO₂抑制常数4.22 mg·m^-3和基础速率系数0.018 2.试验中大部分的NO_x出现损失.     

真菌WZ-Ⅰ对有机磷杀虫剂毒死蜱的酶促降解

从高效降解真菌镰孢霉属WZ-Ⅰ(Fusarium LK.ex Fx)中提取了降解酶,研究了该降解酶的分离条件及对毒死蜱的降解特性,研究表明,其胞内酶对毒死蜱的降解率高达60.8%,细胞碎片对毒死蜱的降解率为48%,但由(NH₄)₂SO₄沉淀提取的胞外酶液对毒死蜱的降解率仅为11.3%,经8次非诱导条件下培养提取粗酶液,酶活力损失较少,判断WZ-Ⅰ菌株的毒死蜱降解酶为胞内酶且属于组成酶.以牛血清白蛋白为标准蛋白测得粗提酶中可溶性蛋白的含量为3.36mg·mL^-1;该酶对毒死蜱的酶促降解最适pH为6.8,在pH 6.0～9.0之间都有较高的活性;最适温度为40℃,在实验温度范围(20～50℃)内该降解酶均具有较好的降解活性,但在55℃时,酶活迅速降低,降低到最高酶活力的41%.测得粗提酶中其米氏常数K_m为1.049 26mmol·L^-1,v_max为0.253 5μmol·(mg·min)^-1.研究结果表明该酶具有较好的热稳定性和pH稳定性,对热和pH均具有较好的耐受力,高效降解真菌WZ-Ⅰ所产生的胞内酶对毒死蜱具有较好的降解效果.     

高效降解1,4-二烷的固态菌剂制备及其性能研究

1,4-二烷污染的生物修复效果很大程度上取决于其降解菌的活性和数量.本研究在前期获得1,4-二烷高效降解菌Xanthobacter flavus DT8的基础上,研究了该菌的扩大培养方法,并制备了易于贮藏和运输的固态菌剂,考察了菌剂的性能.实验结果表明,菌株X. flavus DT8可在富营养培养基中培养,较优的培养基配方为：Na₂HPO₄·12H₂O 1.0 g·L^-1,NH₄Cl 1.0 g·L^-1,MgSO₄·7H₂O 0.2 g·L^-1,酵母粉5.0 g·L^-1,蛋白胨1.0 g·L^-1,丙酮酸钠1.0 g·L^-1,pH 7.0~7.2.X. flavus DT8经发酵罐中扩大培养后,以草炭、硅藻土为载体,经进一步固态发酵制备了固态菌剂,微生物含量为2.17×10¹¹ CFU·g^-1,对1,4-二烷的降解效果明显优于活菌液.该菌剂具有良好的贮藏稳定性,4℃保藏90 d后对100 mg·L^-1的1,4-二烷48 h内去除率为63%;同时具有良好的底物广谱性,对醇类、苯系物和醚类物质也有很好的降解能力.     

降解微囊藻毒素菌种的筛选和活性研究

研究了滇池底泥和表层水体中的微生物菌群降解微囊藻毒素(Microcystins, MCs)的能力差异,发现底泥中的微生物菌群对MCs有更强的生物降解能力.采用从滇池水华蓝藻细胞中提取提纯的微囊藻毒素作为微生物生长的唯一碳源和氮源,先后经过液体和固体培养基培养后,通过挑取单克隆菌落,分别从底泥中筛选出了能够降解MC-RR和LR的5种不同微生物菌种.其中筛选的菌种D降解MCs的能力最强,在3 d内可将初始浓度分别为60.1 mg·L^-1和38.7 mg·L^-1的MC-RR和LR全部降解,日均降解MC-RR和LR的速率分别高达20.0 mg·L^-1和12.9 mg·L^-1.     

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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