设为首页 | 加入收藏
文献检索:
  • Selective reduction of NO by photo-SCR with ammonia in an annular fixed-film photoreactor
  • Gaseous NO was photocatalytically reduced at room temperature by photo-assisted selective catalytic reduction (photo-SCR) with ammonia over TiO2 in this study. NO reduction efficiency and N2 selectivity were determined from gases composition at the outlet stream of photoreactor. Effect of operating conditions, e.g. light intensity and inlet concentrations of ammonia and oxygen, on the NO reduction efficiency and N2 selectivity were discussed to determine the feasible operating condition for photocatalytic reduction of NO. Experimental results showed that selective catalytic reduction of NO with ammonia over TiO2 in the presence of oxygen was a spontaneous reaction in dark. The photoirradiation on the TiO2 surface caused remarkable photocatalytic reduction of NO to form N2, NO2, and N20 under 254 nm UV illuminations, while almost 90% of N2 selectivity was achieved in this study. The ammonia and oxygen molecules played the roles of reductant and oxidant for NO reduction and active sites regeneration, respectively. The reduction of NO was found to be increased with the increase of inlet ammonia and oxygen concentrations until specific concentrations because of the limited active sites on the surface of TiO2. The kinetic model proposed in this study can be used to reasonably describe the reaction mechanism of photo-SCR.
  • Characterization and performance of V2Os/CeO2 for NH3-SCR of NO at low temperatures
  • A series of CeO2 supported V205 catalysts with various loadings were prepared with different calcination temperatures by the incipient impregnation. The catalysts were evaluated for low temperature selective catalytic reduction (SCR) of NO with ammonia (NH3). The effects of 02 and SO2 on catalytic activity were also studied. The catalysts were characterized by specific surface areas (SBET) and X-ray diffraction (XRD) methods. The experimental results showed that NO conversion changed significantly with the different V205 loading and calcination temperature. With the V205 loading increasing from 0 to 10wt%, NO conversion increased significantly, but decreased at higher loading. The optimum calcination temperature was 400℃. The best catalyst yielded above 80% NO conversion in the reaction temperature range of 160℃-300℃. The formation of CeVO4 on the surface of catalysts caused the decrease of redox ability.
  • Phosphorus release potential and pollution characteristics of sediment in downstream Nansi Lake, China
  • The research aimed to evaluate present and potential phosphorous pollution due to high sedimentary phosphorus load and release from sediment, when external phosphorus was reduced in downstream Nansi Lake. Pollution load of the sediment and overlying water was investigated. Kinetics and isotherms of adsorption/release of sedimentary phosphorus were studied to determine equilibrium phosphate concentration (EPCo) and release potential. Kinetics of phosphorus adsorption on sediment and release from sediment were well described by both the pseudo-first-order rate equation and the pseudo-second- order rate equation, but more appropriate to the pseudo- second-order rate equation with the adsorption/release capacity more close to the measured values, suggesting that the processes were chemically rate controlled and dependent on adsorption capacity. Soluble reactive phosphorus (SRP) sorption isotherms on sediment were best fitted by the modified Langmuir model indicating a monolayer adsorption. By comparing EPC0 and SRP of water, the status (adsorption, releasing or in equilibrium) of sediment phosphorus could be determined. The sediments at site S l, S3, S4, S5, and S7 where the EPC0s were greater than the SRPs, had a potential to release phosphorus into the water column. However, those sediments at S9, S10, and S 12, where the EPC0s were approximately equal to the SRPs, were in impermanent equilibrium with overlying water in status of phosphorus, the sediments can be likely to release phosphorus to the water column once the equilibrium was broken. Therefore, sedimentary phos- phorus can be a secondary pollution source in downstream Nansi Lake.
  • Kinetics of oxidation of dimethyl trisulfide by potassium permanganate in drinking water
  • Metabolites of algae such as geosmin, 2- methylisoborneol etc. are reported to induce pungent odors into drinking water and attract additional scientifc attention. Recently, in China, taste and odor outbreaks in drinking water supply have become increasingly common. In source water affected by eutrophication, dimethyl trisulfide, speculated to be produced by decayed algae, was found to be the source of taste and odor issues and can be removed effectively by usual oxidation agents. In this experimental study, batch scale tests were carried out focusing on the removal of dimethyl trisulfide. Reaction kinetics of dimethyl trisulfide oxidized by potassium permanganate in water had been studied; influence factors such as pH, organic substrate, other existed taste, and odor contaminant in equivalent concentration were also dis- cussed. Results showed that dimethyl trisulfide can be removed by potassium permanganate efficiently; the ratio can reach more than 70% with oxidant dosage of 4 mg. L~ and contact time prolonged to 120 min. The dimethyl trisulfide decomposition followed a second-order kinetics pattern with a rate constant k -- 0.00213 L.(min.mg)-1. Typically, the degradation rate of dimethyl trisulfide was increased with the increasing KMnO4 dosage, but dramatically dropped with the increasing levels of humic acid (1.8-4.5 mg. L-1) and other odor-causing compounds (e.g. fl-cyclocitral, 0-1886.0 pg.L-1). Solution pH (5.2- 9.0) and initial dimethyl trisulfide concentration did not significantly affected the degradation. This study demon- strates that KMnO4 oxidation is an effective option to remove dimethyl trisulfide from water.
  • Concentrations and classification of HCHs and DDTs in soil from the lower reaches of the Jiulong River, China
  • Soil is an important source to other environ- mental media and organisms for organochlorine pesticides (OCPs) bioaccumulation. Twenty-four representative sur- face soil samples were collected from the lower reaches of the Jiulong River, China, in 2009. The concentrations of hexachlorocyclohexane isomers (HCHs) ranged from 0.38 to 39.52 ng.g~, with a mean value of 9.51 ng.g-~. The concentrations of dichlorodiphenyltrichloroethanes (DDTs) and their metabolites were within the ranges of 0.94-700.99 ng. gl, with a mean value of 71.17 ng. g-1. The concentrations of HCHs and DDTs in the soil were lower than the first grade level (50 ng. g-a) of the Chinese Environmental Quality Standard (GB 15618-1995). Hier- archical Cluster Analysis (HCA) and Pearson's bivariate Correlations Analysis (PCA) were used to analyse the distribution and contamination levels of OCPs in this region. The results showed that DDTs were the major contaminants and there were no significant correlations between various OCPs concentrations and the total organic carbon (TOC) contents. A significant positive correlation was observed between HCHs and DDTs (p 〈 0.01), which indicates that HCHs and DDTs may have similar sources and fate in the study area.
  • Indoor carbonyl compounds in an academic building in Beijing, China: concentrations and influencing factors
  • Carbonyl compounds in indoor air are of great concern for their adverse health effects. Between February and May, 2009, concentrations of 13 carbonyl compounds were measured in an academic building in Beijing, China. Total concentration of the detected carbonyls ranged from 20.7 to 189.1 I.tg.m3, and among them acetone and formaldehyde were the most abundant, with mean concentrations of 26.4 and 22.6gg.m-3, respectively. Average indoor concentrations of other carbonyls were below I 0 gg. m~3. Principal component analysis identified a combined effect of common indoor carbonyl sources and ventilation on indoor carbonyl levels. Diurnal variations of the carbonyl compounds were investigated in one office room, and carbonyl concentrations tended to be lower in the daytime than at night, due to enhanced ventilation. Average concentrations of carbonyl compounds in the office room were generally higher in early May than in late February, indicating the influence of temperature. Carbo- nyl source emission rates from both the room and human occupants were estimated during two lectures, based on one-compartment mass balance model. The influence of human occupants on indoor carbonyl concentrations varies with environmental conditions, and may become signifi- cant in the case of a large human occupancy.
  • Characterization of soil low-molecular-weight organic acids in the Karst rocky desertification region of Guizhou Province, China
  • Soil low-molecular-weight (LMW) organic acids play important roles in the soil-forming process and the cycling of nutrients in Karst regions. In this study, we quantified the contents of LMW organic acids (including lactate, acetate, formate, malate, and oxalate) in soil solution over the Karst region of Guizhou Province, China using ion chromatography. The concentration of total LMW organic acids in topsoil solution ranged from 0.358 to 1.823pmol'g-1, with an average of 0.912p.mol.gL The mean concentrations of lactate, acetate, formate, malate, and oxalate were 0.2124-0.089, 0.3024-0.228, 0.301-4-0.214, 0.014zk0.018 and 0.086+0.118 pmol.g-% respectively. There were also significant difference in the contents of these acids among four phases of rocky desertification, and their concentrations decreased with the aggravation of rocky desertification. The concentrations of the LMW organic acids were significantly positive correlated each other. Significant positive correlations were also observed among individual LMW organic acids in soil solution, and between them and soil available P, available K, exchange- able Ca, respectively. Furthermore, the concentrations of LMW organic acids were significantly positively corre- lated with inorganic anions (chlorides, nitrates, and sulfates) in Karst topsoil solution. Therefore, the concen- trations of soil LMW organic acids might be one of driving force in the Karst rock desertification process in Guizhou Province.
  • Optimal locations of monitoring stations in water distribution systems under multiple demand patterns: a flaw of demand coverage method and modification
  • A flaw of demand coverage method in solving optimal monitoring stations problem under multiple demand patterns was identified in this paper. In the demand coverage method, the demand coverage of each set of monitoring stations is calculated by accumulating their demand coverage under each demand pattern, and the impact of temporal distribution between different time periods or demand patterns is ignored. This could lead to miscalculation of the optimal locations of the monitoring stations. To overcome this flaw, this paper presents a Demand Coverage Index (DCI) based method. The optimization considers extended period unsteady hydrau- lics due to the change of nodal demands with time. The method is cast in a genetic algorithm framework for integration with Environmental Protection Agency Net (EPANET) and is demonstrated through example applica- tions. Results show that the set of optimal locations of monitoring stations obtained using the DCI method can represent the water quality of water distribution systems under multiple demand patterns better than the one obtained using previous methods.
  • Plant diversity reduces the effect of multiple heavy metal pollution on soil enzyme activities and microbial community structure
  • It is unclear whether certain plant species and plant diversity could reduce the impacts of multiple heavy metal pollution on soil microbial structure and soil enzyme activities. Random amplified polymorphic DNA (RAPD) was used to analyze the genetic diversity and microbial similarity in planted and unplanted soil under combined cadmium (Cd) and lead (Pb) pollution. A metal hyper- accumulator, Brassica juncea, and a common plant, Festuca arundinacea Schreb, were used in this research. The results showed that microorganism quantity in planted soil significantly increased, compared with that in unplanted soil with Cd and Pb pollution. The order of microbial community sensitivity in response to Cd and Pb stress was as follows: actinomycetes 〉 bacteria 〉 fungi. Respiration, phosphatase, urease and dehydrogenase activity were significantly inhibited due to Cd and Pb stress. Compared with unplanted soil, planted soils have frequently been reported to have higher rates of microbial activity due to the presence of additional surfaces for microbial colonization and organic compounds released by the plant roots. Two coexisting plants could increase microbe population and the activity of phosphatases, dehydrogenases and, in particular, ureases. Soil enzyme activity was higher in B. juncea phytoremediated soil than in F. arundinacea planted soil in this study. Heavy metal pollution decreased the richness of the soil microbial community, but plant diversity increased DNA sequence diversity and maintained DNA sequence diversity at highlevels. The genetic polymorphism under heavy metal stress was higher in B. juncea phytoremediated soil than in F. arundinacea planted soil.
  • Effect of pH on biologic degradation of Microcystis aeruginosa by alga-lysing bacteria in sequencing batch biofilm reactors
  • In this paper, the effect of pH on biological degradation of Microcystis aeruginosa by alga-lysing bacteria in laboratory-scale sequencing batch biofilm reactors (SBBRs) was investigated. After 10 d filming with waste activated sludge, the biological film could be formed, and the bioreactors in which laid polyolefin resin filler were used to treat algal culture. By comparing the removal efficiency of chlorophyll a at different aerobic time, the optimum time was determined as 5 h. Under pH 6.5, 7.5, and 8.5 conditions, the removal rates of Microcystis aeruginosa were respectively 75.9%, 83.6%, and 78.3% (in term of chlorophyll a), and that of Chemical Oxygen Demand (CODMn) were 30.6%, 35.8%, and 33.5%. While the removal efficiencies of ammonia nitrogen (NH+ -N) were all 100%. It was observed that the sequence of the removal efficiencies of algae, NH+ -N and organic matter were pH 7.5 〉 pH 8.5 〉 pH 6.5. The results showed that the dominant alga-lysing bacteria in the SBBRs was strain HM-01, which was identified as Bacillus sp. by Polymerase Chain Reaction (PCR) amplification of the 16S rRNA gene, Basic Local Alignment Search Tool (BLAST) analysis, and compar- ison with sequences in the GenBank nucleotide database. The algicidal activated substance which HM-01 strain excreted could withstand high temperature and pressure, also had better hydrophily and stronger polarity.
  • In situ enhanced bioremediation of dichlorvos by a phyllosphere Flavobacterium strain
  • A bacterium capable of degrading dichlorvos was isolated from the rape phyllosphere and designated YD4. The strain was identified as Flavobacterium sp., based on its phenotypic features and 16S rRNA gene sequence. Strain YD4 was able to utilize dichlorvos as the sole source of phosphorus. In situ enhanced bioremedia- tion of dichlorvos by YD4 was hereafter studied. Chlorpyrifos and phoxim could also be degraded by this strain as the sole phosphorus source. A higher degradation rate of dichlorvos was observed after spraying YD4 onto the surface of rape leaves when compared to the sterilized- YD4 and water-treated samples. The results indicated that pesticide-degrading epiphytic bacterium could become a new way for in situ phyllosphere bioremediation where the hostile niche is unsuitable for other pesticide-degrading bacteria isolated from soil and water.
  • Determination of the principal factors of river water quality through cluster analysis method and its prediction
  • In this paper, an artificial neural network model was built to predict the Chemical Oxygen Demand (CODMn) measured by permanganate index in Songhua River. To enhance the prediction accuracy, principal factors were determined through the analysis of the weight relation between influencing factors and forecasting object using cluster analysis method, which optimized the topological structure of the prediction model input items of the artificial neural network. It was shown that application of the principal factors in water quality prediction model can improve its forecasting skill significantly through the comparison between results of prediction by artificial neural network and the measurements of the CODMn. This methodology is also applicable to various water quality prediction targets of other water bodies and it is valuable for theoretical study and practical application.
  • Macrozoobenthic assemblages in relation to environments of the Yangtze-isolated lakes
  • Eutrophication can shift lakes from a clear, macrophyte-dominated state state, and different habitat to a turbid, algae-dominated condition supports different fauna. Macrozoobenthos are good indicators of water environment, and studies on macrozoobenthic assemblage characteristics can help us to know which state a lake is in, thus provide the basis for its eutrophication control. In this study, a systematic investigation on macrozoobenthos was conducted in 17 Yangtze-isolated lakes to explore the macroecological laws of macrozoobenthic assemblages. Detrended correspondence analysis (DCA) revealed that variance of benthic assemblage structure occurred in two types of lakes. In macrophytic lakes, altogether 51 taxa of macrozoobenthos were identified. The average density and biomass of total macrozoobenthos were 2231 individuals, m2 and 1.69 g dry weight.m-2, respec- tively. Macrozoobenthic assemblage was characterized by dominance of scrapers (i.e. gastropods). In algal lakes, altogether 20 taxa of macrozoobenthos were identified. The average density and biomass of total macrozoobenthos were 2814 individuals.m~2 and 1.38g dry weight.m-2, respectively. Macrozoobenthic assemblage was character- ized by dominance of collector-gatherers (i.e. oligo- chaetes). Wet biomass of submersed macrophytes (BMac) and phytoplankton chlorophyll a concentration (Chla) were demonstrated as the key factor structuring macro- zoobenthic assemblages in macrophytic and algal lakes, respectively.
  • Managing water for life
  • Water is essential for life. In spite of the entire engineering infrastructure devoted to the treatment, regulation and beneficial uses of water, occasionally sufficient quantities and qualities of water become scarce. When this happens, just how do we decide how much less water to allocate to all of us and the activities we engage in to sustain and enhance our quality of life? This paper addresses some of the complexities of answering such a question, especially as society increasingly recognizes the need to provide flow regimes that will maintain healthy aquatic and floodplain ecosystems that also impact the economic, physical and even the spiritual quality of our lives. For we depend on these ecosystems to sustain our wellbeing. We are indeed a part of our ecosystems. We depend upon on aquatic ecosystems to moderate river flow qualities and quantities, reduce the extremes of floods and droughts, reduce erosion, detoxify and decompose water- borne wastes, generate and preserve flood plain soils and renew their fertility, regulate disease carrying organisms, and to enhance recreational benefits of river systems. This question of deciding just how much water to allocate to each water user and for the maintenance of viable aquatic ecosystems, especially when there is not enough, is a complex, and largely political, issue. This issue is likely to become even more complex and political and contentious in the future as populations grow and as water quantities and their qualities become even more variable and uncertain.
  • Decomposition analysis of energy-related carbon dioxide emissions in the iron and steel industry in China
  • This work aims to identify the main factors influencing the energy-related carbon dioxide (CO2) emissions from the iron and steel industry in China during the period of 1995-2007. The logarithmic mean divisia index (LMDI) technique was applied with period-wise analysis and time-series analysis. Changes in energy- related CO2 emissions were decomposed into four factors: emission factor effect, energy structure effect, energy consumption effect, and the steel production effect. The results show that steel production is the major factor responsible for the rise in CO2 emissions during the sampling period; on the other hand the energy consump- tion is the largest contributor to the decrease in C02 emissions. To a lesser extent, the emission factor and energy structure effects have both negative and positive contributions to C02 emissions, respectively. Policy implications are provided regarding the reduction of C02 emissions from the iron and steel industry in China, such as controlling the overgrowth of steel production, improving energy-saving technologies, and introducing low-carbon energy sources into the iron and steel industry.
  • Systematical strategies for wastewater treatment and the generated wastes and greenhouse gases in China
  • China now faces double challenges of water resources shortage and severe water pollution. To resolve Chinese water pollution problems and reduce its impacts on human health, economic growth and social develop- ment, the situation of wastewater treatment was investi- gated. Excess sludge and greenhouse gases (GHGs) emitted during wastewater treatment were also surveyed. It is concluded that Chinese water pollution problems should be systematically resolved with inclusion of wastewater and the solid waste and GHGs generated during wastewater treatment. Strategies proposed for the wastewater treatment in China herein were also adequate for other countries, especially for the developing countries with similar economic conditions to China.
  • Characterization of the dissolved organic matter in sewage effluent of sequence batch reactor: the impact of carbon source
  • Dissolved organic matter (DOM) transforma- tion in sequence batch reactor (SBR) fed with carbon sources of different biodegradability was investigated. During the biologic degradation process, the low mole- cular weight (MW) fraction (〈 1 kDa) gradually decreased, while the refractory compounds with higher aromaticity were aggregated. Size exclusion chromatogra- phy (SEC) and fluorescence of excitation emission matrices (EEM) demonstrated that more biopolymers (polysaccharides or proteins) and humic-like substances were presented in the extracellular polymeric substance (EPS) extracted from the SBR fed with sodium acetate or glucose, while the EPS from SBR fed with slowly biodegradable dissolved organic carbon (DOC) substrate- starch had relatively less biopolymers. Comparing the EfOM in sewage effluent of three SBRs, the effluent from SBR fed with starch is more aromatic. Organic carbon with MW 〉 1 kDa as well as the hydrophobic fraction in DOM gradually increased with the carbon sources changing from sodium acetate to glucose and starch. The DOC fractiona- tion and the EEM all demonstrated that EfOM from the effluent of the SBR fed with starch contained more fulvic acid-like substances comparing with the SBR fed with sodium acetate and glucose.
  • Upgrade of three municipal wastewater treatment lagoons using a high surface area media
  • Abstract Lagoon-based municipal wastewater treatment plants (WWTPs) are facing difficulties meeting the needs of rapid population growth as well as the more stringent requirements of discharge permits. Three municipal WWTPs were modified using a high surface area media with upgraded fine-bubble aeration systems. Performance data collected showed very promising results in terms of five-day biochemical oxygen demand (BOD5), ammonia (NH3) and total suspended solids (TSS) removal. Two-year average ammonia effluents were 4.1 mg. L-1 for Columbia WWTP, 4 mg. L-1 for Larchmont WWTP and 2.1 mg. L-1 for Laurelville WWTE respectively. Two- year average BOD5 effluents were 6.8, 4.9 and 2.7 mg.Ll, and TSS effluents were 15.0, 9.6 and 7.5 mg.L-L The systems also showed low fecal coliform (FC) levels in their effluents.
  • Selective reduction of NO by photo-SCR with ammonia in an annular fixed-film photoreactor(YiangChen CHOU Young KU)
    Characterization and performance of V2Os/CeO2 for NH3-SCR of NO at low temperatures(Caiting LI Qun LI Pei LU Huafei CU11 Guangming ZENG)
    Phosphorus release potential and pollution characteristics of sediment in downstream Nansi Lake, China(Zhijian LI[1,2] Qinyan YUE[1] Baoyu GAO[1] Yanwen WANG[1] Qing LIU[3])
    Kinetics of oxidation of dimethyl trisulfide by potassium permanganate in drinking water(XiaoyanMA[1] Shifei HU[1] Hongyu WANG[1] Jun LI[1] Jing HUANG[1] Yun ZHANG[2] Weigang LU[1] Qingsong LI[3])
    Concentrations and classification of HCHs and DDTs in soil from the lower reaches of the Jiulong River, China(Jiaquan ZHANG[1,2] Shihua QI[1] Xinli XING[1] Lingzhi TAN[1] Wei CHEN[1] Ying HU[1] Dan YANG[1] Chenxi WU[1])
    Indoor carbonyl compounds in an academic building in Beijing, China: concentrations and influencing factors(Chuanjia JIANG Pengyi ZHANG)
    Characterization of soil low-molecular-weight organic acids in the Karst rocky desertification region of Guizhou Province, China(Xiaoliang LI[1] Kiaomin CHEN[1] Xia LIU[2] Lianchuan ZHOU[1] Xinqiang YANG[1])
    Optimal locations of monitoring stations in water distribution systems under multiple demand patterns: a flaw of demand coverage method and modification(Shuming LIU[1] Wenjun LIU[1] Jinduan CHEN[2] Qi WANG[3])
    [EnvironmentalBiology]
    Plant diversity reduces the effect of multiple heavy metal pollution on soil enzyme activities and microbial community structure(Yang GAO[1,4] Chiyuan MIAO[2] Jun XIA[1] Liang MAO[4] Yafeng WANG[3] Pei ZHOU[4])
    Effect of pH on biologic degradation of Microcystis aeruginosa by alga-lysing bacteria in sequencing batch biofilm reactors(Hongjing LI Mengli HAO Jingxian LIU Chen CHEN1 Zhengqiu FAN Xiangrong WANG)
    In situ enhanced bioremediation of dichlorvos by a phyllosphere Flavobacterium strain(Jiying NING Gang GANG Zhihui BAI Qing HU Hongyan QI Anzhou MA Xuliang ZHUAN Guoqiang ZHUANG)
    [EnvironmentalEcology]
    Determination of the principal factors of river water quality through cluster analysis method and its prediction(Liang GUO Ying ZHAO Peng WANG)
    Macrozoobenthic assemblages in relation to environments of the Yangtze-isolated lakes(Baozhu PAN[1,2] Haijun WANG[1] Hongzhu WANG[1] Zhaoyin WANG[3])
    [EnvironmentalPolicyandManagement]
    Managing water for life(Daniel P. LOUCKS[1] Haifeng JIA[2])
    Decomposition analysis of energy-related carbon dioxide emissions in the iron and steel industry in China(Wenqiang SUN Jiuju CAI, Hai YU, Lei DAI)
    [EnvironmentalPollutionControl]
    Systematical strategies for wastewater treatment and the generated wastes and greenhouse gases in China(Jingbo GUO[1] Fang MA[2] Yuanyuan QU[3] Ang LI[2] Liang WANG[4])
    Characterization of the dissolved organic matter in sewage effluent of sequence batch reactor: the impact of carbon source(Jin GUO[1] Feng SHENG[1] Jianhua GUO[2] Xiong YANG[1] Mintao MA[1] Yongzhen PENG[1])
    Upgrade of three municipal wastewater treatment lagoons using a high surface area media(John WANC[1] Peng JINt[2] Paul L. BISHOP[2] Fuzhi LI[3])
    《中国环境科学与工程前沿:英文版》封面

    关于我们 | 网站声明 | 合作伙伴 | 联系方式
    金月芽期刊网 2017 触屏版 电脑版 京ICP备13008804号-2