垃圾渗滤液电化学催化氧化法深度处理研究

研究利用电化学催化氧化法深度处理经生物处理后的垃圾渗滤液时，电压、氧化时间、氯离子浓度及温度对有机物降解的影响。试验结果表明：在电压3．5V，电流密度为7．0mA／cm^2．氧化时间2．5h．氯离子的浓度2000mg／L的条件下，垃圾渗滤液的CODCr由464．0mg／L降低到200．0mg／L，NH3^-N的去除率大于95％。     

Fenton法处理垃圾渗滤液的研究

采用Fenton法氧化处理中年垃圾渗滤液生化出水,对影响双氧水利用率及COD去除率的各种因素,包括初始pH,H2O2／Fe^2＋比率,双氧水投加量、催化剂类型及反应时间等进行了研究。结果表明：Fenton法氧化处理中年垃圾渗滤液生化出水的最佳条件是：初始pH值为7,H2O2／Fe^2＋比率为4：1,双氧水的经济投加量为0．05mol／L,反应时间为3．5h。此时,混合催化剂可提高双氧水的利用率,双氧水利用率为153．9％,COD去除率可达80．5％,处理出水可达到GB16689—1997（（生活垃圾填埋污染控制标准》二级标准（COD≤300mg／L）。     

絮凝法处理难降解垃圾渗滤液的实验研究

用絮凝法对难降解的循环式准好氧垃圾渗滤液进行了处理,以垃圾渗滤液的CODcr去除率为主要考察指标,探讨了絮凝剂、最佳絮凝剂的投加量以及pH值等因素对这类渗滤液处理效果的影响,在此基础上确定了最佳处理条件.结果表明,用硫酸亚铁的絮凝处理效果最好,当浓度为20%的硫酸亚铁投加量为0.7 mL/100 mL,pH值为10,与聚丙烯酰胺(PAM)的投加比例为2:1时,可使垃圾渗滤液的CODcr去除率达到60%,色度去除率达到40%,使渗滤液的CODcr从2654.6 mg/L降到977.8 ms/L,达到国家三级排放标准.     

混凝-吸附法预处理垃圾渗滤液的研究

垃圾渗滤液是一种成分复杂的有毒有害有机废水，主要污染物是有机物．重金属和氨氮。通常采用联合工艺进行处理。笔者研究了混凝一吸附法预处理垃圾渗滤液。试验中采用聚合氯化铝作为混凝剂．最佳投药量为500mg／L：吸附剂采用自制的改性膨润土。结果表明：渗滤液中CODCr的去除率可达79％，氨氮的去除率达46％：重金属的去除率为53％～98％。     

Fe3++草酸盐络合物/H2O2/日光体系对垃圾渗滤液的处理

以Fe^3 草酸盐络合物／H2O2作光氧化剂，利用太阳光对垃圾渗滤液进行了光氧化降解实验。结果表明：在溶液的初始pH为3．0，H2O2投加量为460mg/L，ρ(Fe^3 )为20mg／L条件下，反应60min后，CODC4去除率可达80％左右；溶液的pH，P(H2O2)和ρ(Fe^3 )对光解过程有显著影响，而且在太阳光的照射下，CODCr去除率比在紫外光下高。在一定实验条件下，用日光／H2O2／草酸铁体系对城市垃圾渗滤液处理效果较好，可作为垃圾渗滤液的深度处理。     

铁碳微电解/Fenton试剂联合处理垃圾渗滤液研究

垃圾渗滤液水量、水质波动大,污染强度高,处理困难且费用较高,以扬州市某垃圾填埋场渗滤液为研究对象,采用两种微电解-Fenton组合工艺对垃圾渗滤液进行处理.重点考察了反应时间、H2O2投加量和pH值等因素对渗滤液的处理效果.结果表明:(1)微电解-Fenton组合Ⅰ:当pH值为4.0,H2O2投加量为3 mi/L,反应时间为90 min时,COD去除率达到64.3％,氨氮的去除率为65.9％;(2)微电解-Fenton组合Ⅱ:当pH值为4.0,H2O2投加量为1.0 mL/L,反应时间为90 min时,COD去除率达到71.3％,氨氮的去除率为83.9％.     

芬顿法处理垃圾渗滤液工艺的优化

本文采用Fenton试剂法对垃圾渗滤液进行了研究,探讨了pH、H_2O_2/Fe~(2+)的比值和Fe~(2+)的量等因素对CODcr去除率的影响。结果表明:Fenton法对垃圾渗滤液中COD具有良好的处理效果,最佳条件是:初始pH值为3,H_2O_2/Fe~(2+)的比值为2,Fe~(2+)的量在300mg/L时,垃圾渗滤液的COD去除率可达47%。     

AADR-A/O工艺处理头孢类制药废水

本文论述了AADR—A／O工艺处理头孢类制药废水，研究了该工艺的设计、运行及工艺特点。经运行结果表明，当高浓度废水浓度CODCr为28864～34623mg／L，BOD5 12438～15790mg／L，pH3．9～4．5，SS≤110mg／L，处理水量为96～210m^3／d；低浓度废水CODCr为225～350mg／L，BOD5 106～142mg／L，pH7．0～7．5，SS≤100mg／L，处理水量为1250～1502m^3／d时，处理后出水CODCr≤150mg／L，BOD5≤60mg／L，SS≤100mg／L，NH4-N≤25mg／L，达到了《污水综合排放标准》(GB8978—1996)中的二级标准。对该工艺实际运行成本考核得知：运行处理费用为2．33元／m^3水。     

垃圾渗滤液两级DTRO浓缩液生物蒸发处理研究

以生物膜海绵为微生物载体和膨胀剂,餐厨垃圾为补充碳源,生物蒸发处理垃圾渗滤液两级DTRO浓缩液.同时优化了生物蒸发过程中的COD浓度、最佳通风速率和每轮的投加量.结果表明:生物蒸发处理垃圾渗滤液浓缩液是可行的,且COD浓度越高,生物蒸发效果越佳,当COD浓度为160g/L时,四轮堆体最高温为72℃,水分总去除率为85.2%;虽然低风速堆体温度相对较高,但水分去除相对较少.所以综合堆体温度及水分去除效果,选择通风速率为0.5L/min作为生物蒸发最佳风速;混合液投加量为85%时水分和VS的去除效果最佳,所以选择最佳投加量为85%.     

Fenton氧化法深度处理垃圾渗滤液的试验研究

采用Fenton氧化法对经生化处理后的垃圾渗滤液进行深度处理。结果表明,Fenton反应最佳工艺条件:初始pH值为3,H2O2加入量为3.0mL/L,FeSO4.7H2O加入量为3.5g/L,反应时间120min。生化处理后的垃圾渗滤液经Fenton氧化法深度处理后,CODCr由处理前的300mg/L,降至处理后的93mg/L,去除率达69.0%,出水水质达到新修订的《生活垃圾填埋场污染控制标准》(GB16889-2008)排放标准。     

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

ＲｅｍｏｖａｌｏｆｈｅａｖｙｍｅｔａｌｓｆｒｏｍｓｅｗａｇｅｓｌｕｄｇｅｂｙｌｏｗｃｏｓｔｉｎｇｃｈｅｍｉｃａｌｍｅｔｈｏｄａｎｄｒｅｃｙｃｌｉｎｇｉｎａｇｒｉｃｕｌｔｕｒｅＷｕＱｉｔａｎｇ，ＮｙｉｒａｎｄｅｇｅＰａｓｃａｓｉｅ，ＭｏＣｅｈｕｉＦ...     

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.