SBR法对焦化废水生物脱氮研究

采用SBR工艺对焦化废水的有机物降解和生物脱氮进行了研究。试验结果表明。焦化废水的生物脱氮是以短程硝化／反硝化的途径存在的，而且在好氧阶段存在同时硝化／反硝化（sND）过程。好氧阶段的反硝化效率约占整个反应周期脱氮效率的37．0％。SBR反应器对NH3-N的去除效率在95．8％-99．2％．CODCr的去除效率在85．3％～92．6％。由于出水中NO2-N的积累。NO2—N对CODCr浓度贡献值得关注。     

高浓度氨氮废水的短程硝化研究

采用普通好氧活性污泥驯化培养启动亚硝化反应器，探索了在实验室条件下，亚硝化反应的最适宜条件。结果表明．在温度（T）为35℃，pH值为7．5左右，初始污泥浓度0．7g／L时，控制较高的初始进水氨氨浓度和较低的DO浓度，有利于亚硝化反应的启动：驯化后，反应器内氨氮处理效果良好，即使进水氨氮浓度高达2400mg／L时，氨氮去除率也能达到95％以上;在实验中，亚硝化的最适宜条件为，温度：29～35℃．pH值：7．0～8．0。同时．实验结果表明，在一定范围内，溶解氧浓度越高，亚硝化反应速率越快：C／N比过高会严重抑制亚硝化反应。     

反硝化除磷工艺中二次曝气作用分析

反硝化除磷工艺是根据反硝化除磷菌开发的新工艺．结合试验重点探讨了二次曝气在该工艺中的作用：吹脱反硝化产生的附着于活性污泥上的氮气;缺氧段硝酸盐不足时提供O2作为二级电子受体使DPB污泥充分吸磷：p（COD）／p（N）,p（COD）／p（P）比值偏高时,再生活性污泥。指出二次曝气在反硝化除磷工艺中具有重要作用。     

反硝化生物滤池的挂膜与启动

研究了反硝化生物滤池的挂膜与启动过程,为反硝化生物滤池的挂膜过程提供理论依据。在滤速1．2ngh（HRT=20min）时,当反硝化生物滤池运行到第25天时,进水硝态氮质量浓度由50mg／L左右下降到25mg／L左右时,硝态氮去除负荷由1．18kg／（m^3·d）下降到1．10kg／（m^3·d）,负荷变化很小,说明挂膜成功。在反硝化生物滤池中,氨氮主要由反硝化细菌的合成作用去除,去除率不高。在碳源和硝态氮浓度都充足的情况下,反硝化反应遵循零级反应动力学规律,反硝化速率与污染物浓度无关,只与反硝化菌的数量有关。     

双泥折流板反应器反硝化除磷启动试验研究

以生活污水作为处理对象,采用双泥折流板反应器,进行了反硝化除磷的启动运行试验研究。在进水有机负荷为0．5kg／（m^3．d）,m（C）lm（N）=5,t=30（＋0．5）℃,HRT=11．08h,R=0．4,r=0．38,SRT=20d的条件下,系统对CODCr,TN,TP,氨氮的去除率分别为67％,63％,50％和82％,出水质量浓度分别为70mg／L,18mg／L,2．8mg／L,6．8mg／L．表明采用该装置进行反硝化除磷的研究是可行的。     

合成氨废水短程反硝化特性研究

取自强化A/O工艺处理合成氨废水中试装置的活性污泥,在pH、碳源和温度均不为限制性因素条件下,短程反硝化和全程反硝化均为零级反应.结果表明,相对于全程反硝化,短程反硝化可以节约14.1%的碳源和55.7%的反硝化时间;初始NO2--N为36.82 mg.L-1时反硝化最快,比反硝化速率（以NO2--N/VSS计）为0.509 g.（g.d）-1;pH为7.5时反硝化速率最快,实际运行中应避免缺氧区pH〉9;选择性增殖的反硝化菌对甲醇和乙醇形成了良好的适应性,却对葡萄糖和乙酸等其它低分子易降解有机物产生了不适应性.     

温度和DO对MBBR系统硝化和反硝化的影响

在缺氧/好氧/好氧串联运行的移动床生物膜反应器（MBBR）系统中考察了温度和好氧反应器中溶解氧（DO）水平对生物膜硝化和反硝化过程氮素去除的影响,并通过高通量测序技术探究温度和DO的变化造成的MBBR系统中脱氮功能菌群结构的差异,从而在微观水平解释硝化和反硝化受温度和DO影响的生物学机理.结果表明,系统温度的升高可以同时强化生物膜硝化和反硝化过程,且好氧反应器中DO水平的提高对硝化过程有利,从而提高系统的脱氮效果.本研究中,在系统连续运行阶段,当系统温度和好氧O₁反应器的DO浓度为本研究范围内的最高水平时（即温度=20~22℃、DO=5~8mg O₂/L）,比硝化负荷可达1.60g NH₄⁺-N/（m²·d）以上,而相同温度范围内比反硝化负荷可高达2.84g NO₃^--N/（m²·d）,从而使MBBR系统在该工况条件下获得了最佳的NH₄⁺-N和TN去除率（分别达到了98.7%和85.7%）.温度和DO影响硝化和反硝化的根本原因是温度和DO变化引起了脱氮功能菌群数量和群落结构的改变：当好氧反应器的DO水平下降时,硝化功能细菌的OTUs比例显著降低,尤其是异养硝化细菌的生长受到了严重的抑制;而温度的变化对反硝化细菌的影响主要体现在群落结构的变化.     

电化学氢自养与硫自养集成去除饮用水中的硝酸盐

研究了一种电化学氢自养与硫自养集成去除饮用水中硝酸盐的方法，将2种自养反硝化集成，既可减少以硫作为电子供体产生的SO4^2-，也可以使硫自养反硝化产生的H^ 作为电化学产氢的前驱物。同时，在硫自养段可不添加调pH的CaCO3，避免了出水的硬度升高。试验结果表明，在反应器的水力停留时间（HRT）为1．9－5h，最小电流相应为3－16mA时，NO3^--N去除率达90％以上，出水中NO3^--N和SO4^2-浓度分别低于3．0mg/L和170mg/L,NO2^--N未检出，硫段和电氢段出水pH值均维持在中性附近。     

以聚羟基脂肪酸酯为固体碳源去除地下水中的硝酸盐

研究了可降解聚合物聚羟基脂肪酸酯（PHA）作为固体碳源和生物膜载体去除地下水中硝酸盐的影响因素。结果表明,低温反硝化有较大影响,5℃和10℃时的反硝化速率分别只有30℃时的5%和13%。反硝化对进水pH有较强的适应性,在pH4.5-9.5条件下,反硝化速率介于11.2-15.8mg/（Loh）之间。pH为4.5-8.5时,出水亚硝酸盐的浓度相差不大。DO对以反硝化速率影响不大,当进水DO为0.9mg/L-5.0mg/L时,反硝化速率介于12.6-15.8mg/（Loh）之间,出水NO2-N浓度的最大值为0.15 mg/L。     

新型SBR工艺同步硝化反硝化的研究

新型SBR工艺是在传统SBR工艺基础上进行改进，于反应器中加一隔板而成的。实验研究了不同的C／N、DO和好氧区与缺氧厌氧区体积比对同步硝化反硝化的影响，当进水CODcr NH4^＋-N浓度分别为198-604、48．7～57．0mg／L，DO浓度为1．0～3．0mg／L时反应器中CODcr、NH4^＋-N去除率分别达到89．3％～93．4％、77．6％～97．5％。     

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

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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.