高效纤维滤池应用于城市污水深度处理的研究

采用一种新型的高效纤维滤池对城市污水处理厂二沉池出水进行深度处理,考察了高效纤维滤池对SS和浊度的去除效果,并对进水SS浊度的变化对去除效果的影响以及出水浊度与取样时间的关系进行了研究.试验结果表明,在进水SS的质量浓度为10～50 mg/L、浊度为10～50 NTU条件下,出水的SS的质量浓度和浊度可分别降至10 mg/L和5 NTU以下;随着进水SS浓度和浊度的增大,出水SS浓度和浊度也相应地增大;在同一反冲洗周期内;反冲洗前l min的出水水质最好,反冲洗过程及反冲洗后1～2min过滤效果较差,随着时间的递增,处理效果逐步提高.     

双污泥BCR反硝化同步脱氮除磷的试验研究

利用连续流双污泥生物澄清反应器(BCR)反硝化除磷系统,以模拟城市生活污水为处理对象,研究双污泥系统对COD、NH4+-N、TN的去除效果及不同NO3--N浓度对反硝化除磷的影响。试验结果表明:双污泥BCR反硝化除磷系统对COD、NH4+-N和TN具有良好的去除效果,平均去除率分别为83.22%、97.2%、75.47%。控制生物膜好氧硝化反应池中DO浓度为3、4、5 mg/L,池内NO3--N浓度分别达到22、30、38 mg/L,TP的平均出水浓度分别为2.11、0.96、2.69 mg/L。当硝化池中NO3--N浓度为30 mg/L时,系统的运行情况较好,出水TP的浓度相对较理想。     

A~3/O-MBR工艺反硝化除磷性能研究

为探究自行设计的A~3/O-MBR工艺脱氮除磷性能,以模拟生活污水为处理对象,重点研究了在内循环回流比(γ)为100%,硝化液回流比(α)分别为100%、200%、300%条件下系统反硝化除磷特性。结果表明:缺氧II区是工艺反硝化除磷的关键,系统具有优良的同步脱氮除磷效果,ρ(COD)出水均低于50 mg/L。当回流比为200%时,系统对TN、TP去除效果最好,平均去除率分别为75.46%和88.94%,出水平均ρ(TN)、ρ(TP)分别为14.97 mg/L和0.48 mg/L。通过静态释/吸磷试验测定不同硝化液回流比条件下反硝化聚磷菌占总聚磷菌的比例及污泥含磷量,当回流比为200%时,反硝化聚磷菌所占比例最高达95.47%,该回流比条件下缺氧II区污泥含磷量最高为23.07 mg/L,最大吸磷量为0.2136 g/d。     

倒置A2/O-MBR处理城市污水的中试研究

针对城市生活污水,研究了两点进水倒置A2/O-MBR系统对COD、NH4+-N、TN、TP、出水SS、跨膜压差(TMP)的影响.结果表明,该系统对COD、NH4+-N具有较高的去除率,出水符合GB 18918-2002中一级A标准;当混合液回流比为200%时,系统出水TN浓度小于15 mg.L-1;正常排泥后,系统对TP的去除率达90%左右;在膜丝未大量断裂前,系统出水SS小于10mg.L-1;随着系统的运行,TMP逐渐增大,不正确的曝气方式会导致TMP迅速增加.膜截留对COD、TP、SS有直接去除作用,由于膜滤出水中没有固体损失,可以精确控制污泥龄,有利于世代周期较长的硝化菌和反硝化菌在反应器中生长;当污泥浓度增加到6 500 mg.L-1左右,进水量增加0.5倍对出水水质影响很小.     

硝化液回流比对A2/O-BCO工艺反硝化除磷特性的影响

以低C/N城市生活污水为处理对象,重点考察了硝化液回流比对A2/O - BCO(生物接触氧化)工艺脱氮除磷特性的影响.在A2/O反应池水力停留时间(HRT)为8h,污泥回流比为100% 条件下,将硝化液回流比分别设定为100%、200%、300%和400%进行试验.结果表明, 系统在A2/O中实现了反硝化除磷,具有很好的同步氮磷的去除效果,出水COD浓度均在50mg/L以下.上述不同硝化液回流比下总氮(TN)去除率分别为48.8%、66.5%、75.6%和62.5%,总磷(TP)去除率分别为86.0%、90.3%、91.0%和95.0%.在硝化液回流比为300%时,系统平均出水TN和TP浓度分别为14.96mg/L和0.49mg/L.系统反硝化除磷量随着硝化液回流比的增大略有增加,在硝化液回流比为400%时,反硝化除磷量高达磷总去除量的98%.     

混凝预处理去除煤矿生活污水中污染物的试验研究

为进一步提高COD、SS及TP去除效果,采用絮凝沉淀工艺对煤矿生活污水进行预处理。结果表明,在原水COD、SS、TP浓度分别为185 mg/L、136 mg/L和5.1 mg/L的条件下,PAC或PAFC均可作为絮凝剂与PAM复配处理煤矿生活污水,最优反应条件下的出水COD、SS、TP浓度分别达到63 mg/L、19 mg/L和0.22 mg/L。     

高效沉淀/反硝化滤池处理城镇污水厂尾水的深度提标工艺研究

基于对城镇污水处理厂尾水提标改造的研究,通过高效沉淀池与反硝化滤池联用,对浙江某城镇污水处理厂出水进行处理至特别排放限值。联用工艺处理后,水质满足COD≤30mg/L、BOD5≤6mg/L、SS≤5mg/L、NH3-N≤1.5mg/L、TN≤10mg/L、TP≤0.3mg/L,且出水水质稳定。     

折流生物膜工艺处理低浓度废水试验

折流生物膜工艺是一种利用折流挡板与传统生物膜工艺相结合的新型污水处理技术。研究结果表明:在水力负荷为0.24m3/(m2·h)、气水比为3:1条件下,反应器对COD、氨氮、SS和浊度的去除率分别为83.6%、82.3%、95.3%和98.2%,出水COD、氨氮、SS和浊度分别为18.6,1.07,2.2mg/L和0.5NTU,出水各项污染物指标均优于GB18918-2002《城镇污水处理厂污染物排放标准》的一级标准。     

循环流生物膜反应器同时硝化反硝化实验研究

研究了循环流软性填料生物膜反应器的同时硝化反硝化。实验结果表明,反应器中确实存在着同时硝化反硝化现象。考察了碳氮比(C/N)和溶解氧(DO)对同时硝化反硝化的影响。在进水COD和NH4+—N浓度为500mg/L、15mg/L时,出水COD、NH4+—N和TN浓度<50mg/L、3.0mg/L、4.5mg/L,COD去除率、硝化率和反硝化率分别达到90%、80%和70%。     

PVA膜生物反应器去除效果的研究

应用了一种高亲水性的膜材料——PVA膜材料,处理生活污水,在污泥浓度为8000mg/L,HRT为3.5h的条件下,出水COD值维持在20mg/L以下,平均去除率达到93.3%;氨氮去除率达到90%以上;出水SS在1～3mg/L之间,平均去除率达到98.4%,有的甚至能达到100%;出水水质清澈透明,出水浊度平均在0.81NTU,小于1NTU,优于国家饮用水质标准。     

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.     

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.