检索结果-南通市图书馆

Community analysis of ammonia-oxidizing bacteria in activated sludge of eight wastewater treatment systems

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2010年第4期22卷 627-634页

作者： Xiaohui Wang Xianghua Wen Craig Criddle George Wells Jie Zhang Yin Zhao Department of Environmental Science and Engineering Tsinghua University Beijing 100084 China. Department of Civil and Environmental Engineering Jerry Yang & Akiko Yamazaki Environment & Energy Building Stanford University Stanford CA94305-4020 USA Beijing Drainage Group Co. Ltd. Beijing 100084 China

We investigated the communities of ammonia-oxidizing bacteria （AOB） in activated sludge collected from eight wastewater treatment systems using polymerase chain reaction （PCR） followed by terminal restriction fragment length polymorphism （T-RFLP）, cloning, and sequencing of the α-subunit of the ammonia monooxygenase gene （amoA）. The T-RFLP fingerprint analyses showed that different wastewater treatment systems harbored distinct AOB communities. However, there was no remarkable difference among the AOB T- RFLP profiles from different parts of the same system. The T-RFLP fingerprints showed that a full-scale wastewater treatment plant （WWTP） contained a larger number of dominant AOB species than a pilot-scale reactor. The source of influent affected the AOB community, and the WWTPs treating domestic wastewater contained a higher AOB diversity than those receiving mixed domestic and industrial wastewater. However, the AOB community structure was little affected by the treatment process in this study. Phylogenetic analysis of the cloned amoA genes clearly indicated that all the dominant AOB in the systems was closely related to Nitrosomonas spp. not to Nitrosospira spp. Members of the Nitrosomonas oligotropha and Nitrosomonas communis clusters were found in all samples, while members of Nitrosomonas europaea cluster occurred in some systems.

关键词： activated sludge ammonia-oxidizing bacteria T-RFLP amoA gene wastewater treatment plant

Biosorption of zinc(Ⅱ) from aqueous solution by dried activated sludge

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2010年第5期22卷 675-680页

作者： Chunping Yang Jiaqiang Wang Min Lei Gengxin Xie Guangming Zeng Shenglian Luo College of Environmental Science and Engineering Hunan University Changsha 410082 China School of Environmental and Chemical Engineering Nanchang Hangkong University Nanchang 330063 China Key Laboratory of Environmental Biology and Pollution Control （Hunan University） Ministry of Education Changsha 410082 China

The biosorption potential of dried activated sludge as a biosorbent for zinc（Ⅱ） removal from aqueous solution was *** effects of initial pH,contact time,initial zinc ion concentration,and adsorbent dosage on the biosorption processes were determined,and the equilibrium data were modeled by the Langmuir and Freundlich *** Langmuir isotherm model （R 2=0.999） was proved to fit the equilibrium data much better than the Freundlich isotherm model （R 2=0.918）.The monolayer adsorption capacity of dried activated sludge for zinc（Ⅱ） was found to be 17.86 mg/g at pH of 5 and 25°*** kinetic data were tested using pseudo firstand second-order *** results suggested that the pseudo second-order model （R 2 〉 0.999） was better for the description of the adsorption behavior of zinc（Ⅱ） onto the dried activated *** transform infrared spectral analysis showed that the dominant mechanism of zinc（Ⅱ） biosorption onto the dried activated sludge was the binding between amide groups and zinc ions.

关键词： activated sludge biosorption isotherms kinetics zinc(II)

Purification of total DNA extracted from activated sludge

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2008年第1期20卷 80-87页

作者： SHAN Guobin JIN Wenbiao Edward KHLAM XING Xinhui Baolimei Chemical Engineering Co. Ltd. Dongguan 523581 China. Institute of Biochemical Engineering Department of Chemical Engineering Tsinghua University Beijing 100084 China Department of Urban and Civil Engineering Harbin Institute of Technology Shenzhen Graduate School Shenzhen 518055 China

Purification of the total DNA extracted from activated sludge samples was studied. The effects of extraction buffers and lysis treatments （lysozyme, sodium dodecyl sulfate （SDS）, sonication, mechanical mill and thermal shock） on yield and purity of the total DNA extracted from activated sludge were investigated. It was found that SDS and mechanical mill were the most effective ways for cell lysis, and both gave the highest DNA yields, while by SDS and thermal shock, the purest DNA extract could be obtained. The combination of SDS with other lysis treatment, such as sonication and thermal shock, could apparently increase the DNA yields but also result in severe shearing. For the purification of the crude DNA extract, polyvinyl polypyrrolidone was used for the removal of humic contaminants. Cetyltrimethyl ammonium bromide, potassium acetate and phenol/chloroform were used to remove proteins and polysaccharides from crude DNA. Crude DNA was further purified by isopropanol precipitation. Thus, a suitable protocol was proposed for DNA extraction, yielding about 49.9 mg （total DNA）/g volatile suspended solids, and the DNA extracts were successfully used in PCR amplifications for 16S rDNA and 16S rDNA V3 region. The PCR products of 16S rDNA V3 region allowed the DGGE analysis （denatured gradient gel electrophoresis） to be possible.

关键词： 16S rDNA activated sludge PCR lysis treatment DNA purification wasterwater biotreatment

Immobilization study of biosorption of heavy metal ions onto activated sludge

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2004年第4期16卷 640-645页

作者： WUHai-suo ZHANGAi-qiang WANGLian-sheng StateKeyLaboratoryofPollutionControlandResourcesReuse SchooloftheEnvironmentNanjingUniversityNanjing210093China

activated sludge was immobilized into Ca-alginate beads via entrapment, and biosorption of three heavy metal ions, copper(Ⅱ), zinc(Ⅱ), and chromimum(Ⅱ), from aqueous solution in the concentration range of 10\_100 mg/L was studied by using both entrapped activated sludge and inactivated free biomass at pH≤5. A biphasic metal adsorption pattern was observed in all immobilized biomass experiments. The biosorption of metal ions by the biosorbents increased with the initial concentration increased in the medium. The adsorption rate of immobilized pre-treated activated sludge(PAS) was much lower than that of free PAS due to the increase in mass transfer resistance resulting from the polymeric matrix. Biosorption equilibrium of beads was established in about 20 h and the adsorbed heavy metal ions did not change further with time. No significant effect of temperature was observed in the test for free biomass while immobilized PAS appeared to be strong temperature dependent in the test range of 10 and 40℃. Besides, the content of activated sludge in the calcium alginate bead has an influence on the uptake of heavy metals. The sorption equilibrium was well modeled by Langmuir isotherm, implying monomolecular adsorption mechanism. Carboxyl group in cell wall played an important role in surface adsorption of heavy metal ions on PAS.

关键词： biosorption alginate beads immobilization heavy metal activated sludge wastewater treatment

Adsorption behavior of sulfamethazine in an activated sludge process treating swine wastewater

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2014年第8期26卷 1623-1629页

作者： Weiwei Ben Zhimin Qiang Xiaowei Yin Jiuhui Qu Xun Pan Key Laboratory of Aquatic Science and Technology Research Center for Eco-Environmental SciencesChinese Academy of Sciences Foreign Economic Cooperation Office Ministry of Environmental Protection

Swine wastewater is an important pollution source of antibiotics entering the aquatic environment. In this work,the adsorption behavior of sulfamethazine（SMN）,a commonlyused sulfonamide antibiotic,on activated sludge from a sequencing batch reactor treating swine wastewater was investigated. The results show that the adsorption of SMN on activated sludge was an initially rapid process and reached equilibrium after 6 hr. The removal efficiency of SMN from the water phase increased with an increasing concentration of mixed liquor suspended solids,while the adsorbed concentration of SMN decreased. Solution pH influenced both the speciation of SMN and the surface properties of activated sludge,thus significantly impacting the adsorption process. A linear partition model could give a good fit for the equilibrium concentrations of SMN at the test temperatures（i.e.,10,20 and 30°C）. The partition coefficient（Kd） was determined to be 100.5 L/kg at 20°C,indicating a quite high adsorption capacity for SMN. Thermodynamic analysis revealed that SMN adsorption on activated sludge was an exothermic process. This study could help to clarify the fate and behavior of sulfonamide antibiotics in the activated sludge process and assess consequent environmental risks arising from sludge disposal as well.

关键词： Sulfonamide antibiotics activated sludge Adsorption Swine wastewater treatment

Surface properties of bacteria from activated sludge in relation to bioflocculation

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2010年第12期22卷 1840-1845页

作者： Bing Xie Jidong Gu Jun Lu Key Laboratory of Urbanization and Ecological Restoration of Shanghai Department of Environmental Science & Technology East China Normal University Shanghai 200062 China Laboratory of Environmental Toxicology Department of Ecology & Biodiversity The University of Hong Kong Pokfulam Road Hong Kong SAR China Department of Interdisciplinary Studies Faculty of Health & Environmental Sciences Auckland University of Technology Auckland 1142 New Zealand School of Biological Sciences Faculty of Science University of Auckland Auckland 1142 New Zealand

Two bacterial stains were isolated from the activated sludge and identified as Leucobacter sp. and Alcaligenesfaecalis by 16S rDNA sequencing. Pure cultures of these two strains, representing well or poorly settled bacteria, were used to investigate the mechanism of bioflocculation in activated sludge. Based on the analyses of the characteristics of cells hydrophobicity, ζ-potential, flocculation ability and extracellular polymeric substance （EPS） composition under different growth stages, it was found that the ratio of cell EPS protein had the highly influence on ζ-potential and hydrophobicity, which were important factors to bioflocculation. Cellulase and Proteinase K could destroy the extracellular biopolymer and resulted in a decrease in the hydrophobicity and ζ-potential. However, in our study, the flocculation characteristics exhibited differently in relation to cellulase and Proteinase K. Flocculation of cells treated with cellulase and Proteinase K decreased sharply, and then recovered quickly in cellulase treatment, while cells treated with Proteinase K showed no sign of recovery. This reveals that the presence of protein in extracellular biopolymer plays an important role to the bioflocculation of cells.

关键词： activated sludge hydrophobicity ζ-potential bioflocculation pure culture

Interactions between metal ions and the biopolymer in activated sludge： quantification and effects of system pH value

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2017年第1期11卷 79-87页

作者： Yun Zhou Siqing Xia Binh T. Nguyen Min Long Jiao Zhang Zhiqiang Zhang State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and Engineering Tongji University Shanghai 200092 China Biodesign Swette Center for Environmental Biotechnology Arizona State University Tempe AZ 85287-5701 USA School of Civil Engineering and Transportation Shanghai Urban Construction Vocational College Shanghai 200432 China

The quantification and effects of system pH value on the interactions between Pb（II） and the biopolymer in activated sludge were investigated. The biopolymer had two protein-like fluorescence peaks （Ex/Em = 280 nm1326-338 nm for peak A; Ex/Em = 220-230 nm/324-338 nm for peak B）. The fluorescence intensities of peak B were higher than those of peak A. The fluorophores of both peaks could be largely quenched by Pb（ll）, and the quencher dose for peak B was about half of that for peak A. The modified Stern-Volmer equation well depicted the fluorescence quenching titration. The quenching constant （Ka） values for both peaks decreased with rising system pH value, and then sharply decreased under alkaline conditions. It could be attributed to that the alkaline conditions caused the reduction of available Pb（II） due to the occurrence of Pb（OH）2 sediments. The Ka values of peak B were bigger than those for peak A at the same system pH values. Accordingly, the aromatic proteins （peak B） played a key role in the interactions between metal ions and the biopolymer.

关键词： Metal ions Biopolymer activated sludge Three-dimensional excitation emission matrix (3D-EEM) Fluorescence regional integration (FRI) technique Quantification

Experimental study on pressurized activated sludge process for high concentration pesticide wastewater

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2010年第9期22卷 1342-1347页

作者： Zanfang Jin, Zhiyan Pan, Shangqin Yu, Chunmian Lin College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China. College of Biological and Environmental Engineering Zhejiang University of Technology Hangzhou 310032 China

Pressurized biochemical process derived from traditional activated sludge processes is an innovative technology for wastewater treatment. The main advantage of the pressurized process is that the oxygen transfer barrier can be overcome by increasing the dissolved oxygen level. In this study, high concentration pesticide wastewater was treated by pressurized activated sludge process. It was found that the removal of chemical oxygen demand （COD） increased steadily with the increase of operating pressure, aeration time, and sludge concentration. When the operation pressure was 0.30 MPa and the aeration time was 6 hr, 85.0%-92.5% COD, corresponding to an effluent COD of 230-370 mg/L, was removed from an influent COD of 2500-5000 mg/L. The obtained outlet COD concentration was lower than 350-450 mg/L for the identical process operated under the atmospheric pressure. In addition, pressurized biochemical process could produce a higher COD volumetric loading rate at 5.8-7.6 kg COD/（m^***）, compared with 2.0-2.8 kg COD/（***） using the same equipment at the atmospheric pressure. The COD concentration followed a modified Monod model with Vmax 2.31 day-1 and Ks 487 mg/L.

关键词： pressurized biochemical process pesticide wastewater activated sludge kinetics

Tank-dependence of the functionality and network differentiation of activated sludge community in a full-scale anaerobic/anoxic/aerobic municipal sewage treatment plant

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2023年第3期17卷 107-120页

作者： Hongcan Cui Ronghua Xu Zhong Yu Yuanyuan Yao Shaoqing Zhang Fangang Meng School of Environmental Science and Engineering Sun Yat-sen UniversityGuangzhou 510275China Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology Sun Yat-sen UniversityGuangzhou 510275China

Understanding the structures and dynamics of bacterial communities in activated sludge(AS)in full-scale wastewater treatment plants(WWTPs)is of both engineering and ecological *** investigations have mainly focused on the AS communities of WWTP aeration tanks,and the differences and interactions between the communities in anaerobic and anoxic tanks of the AS system remain poorly ***,we investigated the structures of bacterial communities and their inter-connections in three tanks(anaerobic,anoxic,and aerobic)and influent from a full-scale WWTP with conventional anaerobic/anoxic/aerobic(A/A/O)process over a year to explore their functionality and network ***-throughput sequencing showed that community compositions did not differ appreciably between the different tanks,likely due to the continuous sludge community interchange between ***,network analysis showed significant differences in inter-species relationships,OTU topological roles,and keystone populations in the different AS ***,the anoxic network is expected to be more unstable and easily affected by environmental ***-associated environmental factors,including dissolved oxygen,pH,and nutrients,were found to affect the relative abundance of functional genera(i.e.,AOB,NOB,PAOs,and denitrifiers),suggesting that these groups were more susceptible to environmental variables than other ***,this work could assist in improving our understanding of tank-associated microbial ecology,particularly the response of functional bacteria to seasonal variations in WWTPs employing A/A/O process.

关键词： activated sludge Bacterial community Tank-dependence Network association Functional bacteria