固定化微生物处理含氨臭气的研究

采用海藻酸钙包埋固定化生物颗粒,利用固定床反应器处理含氨臭气的研究结果表明,系统的脱臭、硝化效果较好;其气相NH₃去除率在92％以上,固定化生物颗粒的硝化速度大于0.63gN/kg固定化湿颗粒·d,远高于土壤及生物膜NH₃气脱臭法。对进气NH₃－N负荷、pH值、水份喷淋密度与硝化、脱臭效果的关系研究结果表明,系统获得高效脱臭、硝化效果的最佳进气负荷为3.99gN/kg固定化湿颗粒·d,pH值为7.0～8.0,淋洗密度为0.61m³/m²塔截面·d。     

垂直流湿地处理低浓度生活污水的水力负荷

在5种水力负荷条件下,采用连续进水、间歇排水的运行方式,对2种垂直流湿地处理低浓度生活污水的去除效果进行了研究.结果表明,在水力负荷为0.085,0.106,0.141,0.212m³/(m²d)的条件下,多层填料(1#)湿地和双层填料(2#)湿地对COD_Cr和NH_{4⁺-N的去除无明显差异,出水CODCr和NH4⁺-N浓度均低于30mg/L和5mg/L.两垂直流湿地CODCr净化负荷与有机污染负荷之间呈显著的正相关关系(n=4R2>0.98).垂直流湿地中氮的去除主要是依靠微生物的硝化和反硝化作用;进水水质、水力负荷和温度等影响湿地系统硝化和反硝化作用的进行,水力负荷为0.141m³/(m²d)时,总氮(TN)去除效率与有机污染负荷呈正相关.}     

硫酸盐还原菌颗粒污泥形成条件研究

在生物反应器中培养出高活性的生物相是使其稳定、高效运行的关键．在上流式厌氧污泥床反应器中,对硫酸盐还原菌颗粒污泥形成过程及形成条件进行了研究,结果表明,在中温（35 ±1 ℃） 条件下,当进水SO^2-₄ 小于1600mg/L、COD/SO^2-₄大于3 时,控制反应器污泥负荷大于0.3kgsO^2-₄/kg Vss·d 、水力负荷为0.2m³/m²·h 有利于颗粒污泥的形成和生长．     

厌氧酸化-好氧光合细菌法处理含硫酸盐高浓度有机废水

采用抑制硫酸盐还原的厌氧酸化工艺与两级好氧光合细菌工艺组合技术,处理含硫酸盐高浓度有机废水,实现了硫酸盐不转化状态下的污染物高效去除.结果表明,当连续流酸化反应器内挥发酸浓度达31112mgCOD/L以上时,硫酸盐还原将被完全抑制.酸化段采用CODCr为44251mg/L的较高进水浓度,容积负荷25.0kgCOD/(m³·d),出水经稀释后进入容积负荷为4.0kgCOD/(m³·d)的两级好氧膜法光合细菌反应器,最终COD_Cr去除率达99.0%,总氮去除率67.5%,而硫酸盐还原被完全抑制.在两级PSB反应器中,PSB2反应器主要起脱氮作用,较高的DO(5.0～6.0mg/L)有利于脱氮.     

好氧反硝化SBR工艺启动研究

该文以人工模拟的高C/N比(10)废水为处理对象,利用缺氧/好氧交替和高曝气的运行方式,以城市生活污水处理厂污泥作为接种污泥,研究了好氧反硝化序批式活性污泥反应器(SBR反应器)的启动过程。结果表明:在SBR反应器启动45 d后,出现明显的好氧反硝化过程;继续培养25 d,好氧反硝化SBR反应器的脱氮效率达到稳定。当反应器污泥负荷为0.11 kg COD/(kg MLSS·d)时,好氧反硝化SBR反应器对COD、总氮和氨氮的去除效率分别为(94.97%±0.53%)、(90.37%±5.89%)和(99.18%±0.34%)。城市生活污水处理厂污泥可用于好氧反硝化生物脱氮工艺的启动,缺氧/好氧交替和高曝气的方式可以加速好氧反硝化工艺的启动。     

厌氧－缺氧－好氧处理城市废水系统缺氧相中的脱氮硫杆菌

利用厌氧－缺氧－好氧处理城市废水的中试规模系统,对其缺氧相中的脱氮硫杆菌进行了研究。结果表明,脱氮硫杆菌的最高脱氮作用率、氧化Na₂S的最高浓度、S^2-的最高污泥负荷率和污泥中脱氮硫杆菌的最高含量（MPN）分别为3.6mg－NO^－₃/gVSS·h、1750mg/L、25mg－S^2-/gVSS·d和1.1×10⁸/gVSS。脱氮硫杆菌在氧化二价硫成硫酸并还原硝酸为氮气的过程中起着相当有意义的作用。     

反应器分区提高生物接触氧化硝化性能的研究

为克服普通生物接触氧化反应器中因硝化菌与有机物降解菌的竞争劣势而影响硝化活性的问题,将反应器简单分隔,通过微生物生态调控,以提高硝化性能.结果表明,在BOD、TN负荷分别为1.0、0.19kg/(m³·d)的中等负荷条件下,反应器分区后硝化率提高33%.反应器两区分别形成以降解有机物和硝化为主的功能区.分区式接触氧化反应器后区段的硝化速率是单区式反应器的2.8～4.5倍,亚硝酸菌密度提高1个数量级.分区式反应器在0.26kg/(m³·d)的高TN负荷条件下运行时,由于硝化细菌活性降低导致硝化率降低,而在0.08kg/(m³·d)的低负荷条件下运行时,后区段过低的氨氮浓度限制了硝化能力的发挥,因此分区式反应器宜在中等负荷下运行.     

三沟式氧化沟污水处理工艺的性能分析

以生产性10万m³/d规模的三沟式氧化沟作为研究对象。研究结果表明,该工艺运行稳定,满足BOD₅和悬浮物浓度小于30mg/L出现的频率分别为92％和96％;剩余污泥得到一定程度的稳定;污水处理的比能耗为1.20kW·h/去除kgBOD₅;另外还观察到反硝化运行和硝化运行的时间比tDN/tN对调节三沟式氧化沟脱氮效果起着重要的作用;并就三沟式氧化沟改扩建提出了建议。     

硝化负荷对A~2O-BAF中试系统性能的影响

该文建立了一套中试规模"厌氧/缺氧/短时好氧(A2O)-曝气生物滤池(BAF)工艺",日处理量19.2 m3/d,考察了BAF池硝化负荷对系统处理性能的影响。该工艺由A2O池、中沉池和BAF池三部分构成,其中,A2O段HRT为4.0 h,厌氧/缺氧/好氧体积比为1∶2∶1;BAF池最初只有1座,后来改为2座,硝化负荷从0.8 kg NH4+-N/(m3·d)降至0.4 kg NH4+-N/(m3·d),硝化液回流比100%。结果表明,随着硝化负荷的降低,系统去除效果明显改善,氨氮和总氮去除率分别从66.2%和51.7%提高到88.0%和69.9%,SS去除率也从55.6%升至82.3%;COD去除效果保持稳定,平均去除率82.5%。可见,BAF容积负荷是影响A2O-BAF工艺处理性能的关键参数,将硝化负荷控制在0.4 kg NH4+-N/(m3·d)可保证系统出水达到《城镇污水处理厂污染物排放标准》一级A标准。     

厌氧－缺氧－好氧工艺去除废水中COD、氮和磷的研究

为了减少废水中营养盐的排放量,采用实验室规模的厌氧─缺氧─好氧工艺处理豆制品废水。结果表明,TCOD、SCOD、NH⁺₄-N、NO^-₃－N、TN、TP、SP（可溶性磷）、SS、细菌总数和大肠菌群数的去除率分别为96%、94％、93％、89％、82％、88％、78％、98.0％、99.9％以上。厌氧相产气率平均0.4L/L·d,上所产气体中平均甲烷含量69.8％,CO₂3.8％,N226.4%。缺氧相产气率平均为0.2L/L·d,平均甲烷含量59.5％,CO₂12％,N₂39.2％。好氧相中亚硝酸细菌含量为1.1×10⁵/mL,硝酸细菌含量为1.4×10³/mL。     

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.     

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.     

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.     

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.     

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.     

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.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.