水深对立体种植沉水植物污染物去除效果的影响

选取苦草和黑藻两种沉水植物作为实验材料,考察了水深对COD_(Mn)、总氮和总磷去除效果的影响。结果表明:经过14天处理,苦草和黑藻在1.5 m水深对水体中COD_(Mn)的去除率分别达到52%和56%;经过12天处理,两种沉水植物水样总氮含量均低于1.0 mg·L~(-1),1.2 m水深的除氮效率比0.3 m水深分别提高13%和20%;经过8天处理后,两种沉水植物在0.9 m至1.2 m水深总磷含量均低于0.05 mg·L~(-1),除磷效率均超过62%;水深对于沉水植物污染物去除效果的影响来自根/茎生长及植物表面生物膜量的增加,0.9 m和1.5 m水深表面有机质含量高于其他水深,分别占鲜重2.53 mg·g~(-1)和2.72 mg·g~(-1),有机质含量提高了约12%;水深为1.5 m时,苦草和黑藻的根长较1.2 m水深分别减小8%和40%,由此导致COD_(Mn)和总氮去除效果在1.5 m水深范围内没有明显变化;苦草和黑藻的最佳种植深度为0.9～1.2 m。     

自动增氧型潜流人工湿地处理农村生活污水的研究

采用人工配水模拟太湖地区农村生活污水水质,利用改进的自动增氧型潜流人工湿地对其进行处理,结果表明:COD、NH4 -N、TP进水浓度分别在132.4～392.6mg·L-1、21.58～50.26mg·L-1、3.60～13.17mg·L-1范围内变化时,COD、NH4 -N、TP的去除负荷随着进水浓度的升高而增大,其最高去除负荷分别为226.38 kg·d-1·hm-2、44.40 kg·d-1·hm-2、10.44 kg·d-1·hm-2,相应的去除率为89.45%、88.93%、90.25%,且系统有较强的抗冲击负荷能力.     

溶解氧对Biolak型A2O工艺脱氮除磷性能的影响

通过对Biolak型A2O工艺处理生活污水工程应用的研究,考察了好氧段溶解氧(DO)浓度对该工艺脱氮除磷的影响.试验结果表明,DO浓度变化对系统COD、NH+4-N处理效果的影响不大,而对系统总氮及总磷的去除效果影响显著.当DO浓度控制在0.80~1.50 mg·L-1之间时,系统总氮去除效果最佳,可以达到69.5%,系统好氧段可实现同步硝化反硝化除氮.通过对系统氮进行物料衡算发现,23.7%的总氮通过好氧段多级A/O反硝化脱氮去除.当DO浓度为1.00~3.00 mg·L-1时,总磷(TP)去除率较高,可以达到74.0%.DO浓度控制在1.00~1.50 mg·L-1之间时,系统脱氮除磷效果最佳,此时TN、TP的去除率分别为68.9%、73.7%,二级生化处理段出水TN、TP分别为12.02、0.95 mg·L-1.     

ASBR+SBR处理生活污水试验研究

采用ASBR+SBR工艺,进行处理小流量生活污水的试验研究。结果表明,先通过ASBR反应器对污水起到平衡、均化作用,再通过SBR反应器实现污水的脱氮除磷。试验出水CODCr浓度为21～43mg·L-1,去除率达到85～93%;出水NH3-N浓度为3 3～9 5mg·L-1,去除率达到65～81%;出水TP浓度为0 32～0 63mg·L-1,去除率达到87～95%。     

内循环SBR反应器无厌氧段实现同步脱氮除磷

研究了内循环SBR反应器在模拟城市生活污水处理中脱氮除磷的效果.结果表明,在曝气时间为4h,曝气开始时DO浓度为6mg·L-1,pH值7～8时,反应器对COD、NH4 -N、TP均有较好的去除效果,进水中COD浓度、NH4 -N浓度、TP浓度分别由170～260mg·L-1、20～30mg·L-1、8～20mg·L-1降到出水的4～48mg·L-1、0～2.0mg·L-1和0～1.4mg·L-1,COD、TIN(NH4 -N NO3--N N02--N)的去除率分别为89.7%±6.5%、70%左右,NH4 -N的转化率为97.4%±3.6%、TP的去除率为95.6%±4.4%.在本研究的实验过程中反应器进水后未经过传统除磷理论认为所必须的厌氧段而直接曝气,TP的去除效果仍然良好且运行稳定,这和传统的理论与研究有所区别.     

生物脱氮系统中无厌氧释磷的生物除磷工艺

采用2个工作容积为6L的SBR反应器(1#和2#)分别进行人工废水的脱氮试验研究,其中1#进水是以醋酸钠为碳源,2#以淀粉为碳源,2个反应器进水的COD、氨氮、磷酸盐和硝氮浓度一致.2个反应器均按缺氧76min-好氧294min交替的模式运行·在COD/NO-3N比为8.76:1(400 mg·L-1:45.67 mg·L-1)和15.03:1(400 mg·L-1:26.61 mg·L-1)2种水质条件下.考察了2个反应器对COD、氮和磷的脱除情况.结果表明.2种碳氮比下,1#反应器为传统的硝化.反硝化生物脱氮.对硝酸盐和COD具有较好的脱除效果,对磷基本不能去除;2#反应器在缺氧段发生反硝化脱氮作用,在好氧时段发生硝化作用,同时伴有明显的磷去除.这种现象稳定持续,致使反应器中污泥浓度明显增加.结合pH、DO等环境因素的分析,判定这是一种新型的非传统生物除磷现象.     

不同好/厌氧区容积负荷对生物膜/颗粒污泥耦合工艺脱氮除磷的影响

采用自行设计的生物膜/颗粒污泥耦合反应器,研究不同好/厌氧区容积负荷对该工艺脱氮除磷的影响.试验过程中设置了3种不同的工况,每种工况的好氧区和厌氧区容积均不同,工况Ⅰ的是9.66 L和15.34 L,工况Ⅱ的分别为12.56 L和12.44 L,工况Ⅲ的是15.42 L和9.58 L.不同的好/厌氧区容积对应不同的容积负荷.结果表明,工况Ⅰ的氨氮与磷酸盐去除效果稍差,工况Ⅲ出水硝态氮较高,造成总氮去除率较低.工况Ⅱ是最佳运行条件,系统的氨氮去除率为80.63%,氮容积去除负荷为150.27 g·(m3·d)-1,COD去除率为83.24%,释磷量与吸磷量分别为7.23 mg·L-1和11.93 mg·L-1.     

规模化猪场养殖废水UASB-SFSBR-MAP处理工艺中试研究

针对规模化猪场养殖废水常规厌氧-好氧组合处理工艺及SBR处理工艺脱氮效率低、运行费用高、养分流失大等技术难题,提出了养殖废水"UASB-SFSBR(分步进水序批式反应器)-MAP(磷酸铵镁结晶)"处理工艺,并开展了中试工程研究.结果表明,UASB-SFSBR-MAP处理工艺对COD、NH4+-N和TP的去除率分别达到95.1%、92.7%和88.8%,MAP氮磷回收率达23.9%和83.8%.工艺出水水质COD≤135 mg·L-1、TN<116 mg·L-1、NH4+-N<43 mg·L-1、TP≤7.3 mg·L-1、SS≤50mg·L-1,各项指标优于《畜禽养殖业污染物排放标准》(GB 18596-2001).该处理工艺稳定可靠,生物脱氮过程保持系统碳源碱度自平衡,实现碳氮磷高效处理和回收,处理费用与传统厌氧-好氧处理工艺相当.因此,UASB-SFSBR-MAP组合处理工艺具有较高的推广应用价值,适合我国规模化猪场养殖废水的达标处理.     

低浓度铬对SBR中微生物抑制影响研究

研究了低浓度铬(三价和六价)对SBR生物系统的抑制影响,考察了两种不同SBR工艺(传统工艺和分段进水工艺)在处理含低浓度铬废水过程中常规的出水水质和活性污泥性状的变化,以及微生物群落的变迁.研究结果表明,在进水总铬(Cr(III)∶Cr(VI)=4∶1)浓度为0.5mg·L-1的条件下,传统工艺和分段进水工艺的氨氮去除率由99%分别下降至70%和65%,同时,磷酸盐去除率也由99%分别下降至51%和43%.当进水中总铬浓度达到1 mg·L-1时,分段进水工艺SBR系统的氨氮和磷酸盐去除率最终分别下降至44%和37%.此外,多糖和蛋白质的分泌量变化分别呈下降和上升趋势.高通量测序结果表明,活性污泥细菌群落丰富度和多样性受到了铬离子的影响,并且Nitrospira、Acidobacteria、Planctomycetes、Cyanobacteria和Candidatus_Accumulibacter等脱氮除磷功能菌种的生长都受到了一定程度的抑制,也与被抑制的SBR系统脱氮除磷去除率下降的宏观现象相吻合.     

低碳源条件下改良双污泥系统脱氮除磷优化研究

在低碳源废水条件下,通过对改良后的双污泥处理工艺与传统厌氧-好氧-缺氧工艺效果进行比较分析,探究解决城市生活污水碳源不足的方法.实验组反应器为改良型双污泥系统,即在原双污泥系统缺氧段增加两个阶段的微曝气(曝气量0.5 L·min~(-1)),对照组反应器为多级厌氧-好氧-缺氧SBR.结果表明,进水COD、氨氮、SOP浓度分别为200、35、10 mg·L-1时,实验组比对照组脱氮除磷效果好(去除率分别为:TN 94.8%与60.9%;TP 96.5%与75%),出水SOP浓度0.35 mg·L-1,NH+4-N浓度0.50 mg·L-1,TN浓度1.82 mg·L-1,完全满足《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级A标准.采用优化后的工艺,单位碳源(以COD计)可实现的最大的氮、磷的去除量分别为0.17 g·g-1和0.048 g·g-1,可以最大程度地解决当前城市废水碳源浓度较低的问题.     

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.     

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.     

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.     

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.     

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.     

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.