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．     

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。     

催化氧化法处理甲硫醇废气

用催化氧化法处理含硫有机废气,燃烧催化剂是主要活性组分为V₂0₅、过渡金属氧化物（MO_x）和微量贵金属,负载在经特殊方法处理的天然沸石上。50m³/h中试装置的甲硫醇废气的载线试验和1500m³/h工业装置的运转结果表明,催化剂反应后的温升明显,净化率≥95％,氧化产物（Sox）经稀碱吸收,消除了二次污染。     

生物滤池与固定——悬浮填料复合式生物膜反应器脱臭

为了探讨生物法处理含H₂S恶臭气体的效率及酸积累问题,利用两种生物反应器进行了处理H₂S的试验研究．结果表明,生物滤池脱臭效率高,但液相H₂SO₄积累明显,pH值低．复合式生物膜反应器装有固定一悬浮填料,集生物过滤和生物吸收为一体,当容积负荷N_v≤190gH₂S/m³·d时,具有很高的去除能力,液相pH≥6．     

缺氧－好氧生物膜法脱氮技术的研究

为了防止氮污染对水体造成的危害,我国对氨氮排放实行严格的控制。采用缺氧－好氧淹没式生物膜脱氮方法研究其处理效果与工艺参数,并着重研究氮负荷和碳源对硝化、反硝化的影响;微生物在膜上的分布特性及其对底质变化的影响。研究结果表明：缺氧段（A段）停留时间为7.3h,好氧段（0段）为15.7h好氧段容积负荷：COD0.36kg/m³·d,NH₃－N0.35kg/m³·d;缺氧段硝态氮负荷0.65kg/m³·d,COD负荷1.7kg/m³·d。这一水处理技术工艺稳定,NH₃－N与NO_x－N的去除率均在90％以上,而且生物活性强,分布较均匀,是目前控制氮污染的有效方法。     

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.}     

一体式膜-生物反应器降低能耗的中试试验

基于气升式内循环反应器原理,对一体式膜-生物反应器结构进行了优化设计,构建了处理量为15.6m³/d的中试装置.通过水动力学特性的考察,得到中试装置的经济曝气强度为96m³/(m²·h);通过经济曝气强度条件下的临界通量试验,得到污泥浓度小于13g/L时的膜临界通量区域为30～35L/(m²·h).由此确定了中试装置连续运行的操作参数,实现了次临界通量[30L/(m²·h)]条件下处理城市污水的稳定运行.能耗分析显示,该中试反应器的气水比为21:1,有效单位产水能耗为0.42kW·h/m³.     

β-环糊精/Ce/TiO2 光催化氧化气相甲苯

为提高光催化剂对气相污染物的吸附和光催化净化效果,选取不锈钢网作载体,由溶胶－凝胶法、2 次涂敷和烧结制备活性较高的1%Ce/TiO₂ 催化剂,经浸渍吸附β-环糊精(β-CD),获得β-CD 修饰的Ce/TiO₂ 催化剂;用X 射线衍射、扫描电镜、透射电镜等手段表征了催化剂的结构性质;考察了该催化剂对空气中甲苯污染物的光催化氧化活性.结果表明,反应4~5h,修饰薄膜催化剂可将初始浓度为70mg/m³的甲苯100%氧化去除,且重复使用3 次后去除率仍为100%;反应3h 可将初始浓度为97mg/m³ 的甲苯100％氧化;初始浓度为208mg/m³ 时,甲苯氧化转化率为80%以上.实验表明,β-CD修饰的催化剂单位面积比活性比未修饰的Ce/TiO₂催化剂提高0.59 倍,对甲苯的去除率分别增加35%和20%.     

河底沉积物培养耐酸产甲烷颗粒污泥的试验研究

利用河底沉积物作为接种污泥,在一个3.1L的EGSB反应器中进行培养耐酸产甲烷颗粒污泥的试验研究.结果表明,EGSB反应器在pH6.0,出水碱度低于400mg CaCO3/L,容积负荷5.3kg COD/(m³d)的条件下培养出具有良好沉降性能和产甲烷活性的耐酸颗粒污泥.形成耐酸颗粒污泥后,EGSB反应器在pH5.8～6.0,进水COD 3000mg/L,容积负荷5.2kg COD/(m³d)的条件下稳定运行29d, COD去除率平均为89.2%,出水总碱度仅为264.4mg CaCO₃/L,沼气中甲烷的含量约为56.9%.扫描电镜观察发现颗粒污泥内部存在成簇生长的索氏甲烷丝菌     

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.     

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.     

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.     

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.     

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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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.     

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.