Dec 2009, Volume 3 Issue 4
    

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  • Research articles
    Effects of nitrate concentration on biological hydrogen production by mixed cultures
    Bo WANG, Wei WAN, Jianlong WANG,
    2009, 3(4): 380-386. https://doi.org/10.1007/s11783-009-0142-0
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    The effects of nitrate on fermentative hydrogen production and soluble metabolites from mixed cultures were investigated by varying nitrate concentrations from 0 to 10g N/L at 35°C with an initial pH of 7.0. The results showed that the substrate degradation rate, hydrogen production potential, hydrogen yield, and average hydrogen production rate initially increased with increasing nitrate concentrations from 0 to 0.1g N/L, while they decreased with increasing nitrate concentrations from 0.1 to 10g N/L. The maximum hydrogen production potential of 305.0mL, maximum hydrogen yield of 313.1mL/g glucose, and maximum average hydrogen production rate of 13.3mL/h were obtained at a nitrate concentration of 0.1g N/L. The soluble metabolites produced by the mixed cultures contained only ethanol and acetic acid (HAc) without propionic acid (HPr) and butyric acid (HBu). This study used the Modified Logistic model to describe the progress of cumulative hydrogen production in batch tests. A concise model was proposed to describe the effects of nitrate concentration on average hydrogen production rate.
  • Research articles
    Enhanced biohydrogen generation from organic wastewater containing N H 4 + by phototrophic bacteria Rhodobacter sphaeroides AR-3
    Guanghong ZHENG, Zhuhui KANG, Yifan QIAN, Lei WANG,
    2009, 3(4): 387-392. https://doi.org/10.1007/s11783-009-0154-9
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    "Graphic" is typically an inhibitor to hydrogen production from organic wastewater by photo-bacteria. In this experiment, biohydrogen generation with wild-typeanoxygenic phototrophic bacterium Rhodobacter sphaeroideswas found to be sensitive to "Graphic" due to the significant inhibition of "Graphic" to its nitrogenase. In order to avoid the inhibition of "Graphic" to biohydrogen generation by R. sphaeroides, a glutamine auxotrophic mutant R. sphaeroides AR-3 was obtained by mutagenizing with ethyl methane sulfonate. The AR-3 mutant could generate biohydrogen efficiently in the hydrogen production medium with a higher "Graphic" concentration, because the inhibition of "Graphic" to nitrogenase of AR-3 was released. Under suitable conditions, AR-3 effectively produced biohydrogen from tofu wastewater with an average generation rate of 14.2 mL/L·h. This generation rate was increased by more than 100% compared with that from wild-type R. sphaeroides.
  • Research articles
    Application of proteomics in environmental science
    Xiaona CHU, Jiangyong HU, Say Leong ONG,
    2009, 3(4): 393-403. https://doi.org/10.1007/s11783-009-0145-x
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    Proteomics involves the separation of proteins, identification of the amino acid sequence of the interested or target proteins, study of the function of the proteins, modification, structure and ultimate assignments to functional pathways in the cell. The proteomic investigations have contributed greatly to human diseases studies, new drugs discovery researches, and environmental science in recent years. This article provides a review on the development of the main proteomic technologies, including both the gel based and non-gel based technologies, and their applications in environmental science. Proteomic technologies have been utilized in the environmental stresses studies to analyze the induction or reduction of proteins at expression level and identify the target proteins to investigate their function in response to environmental stresses, such as high or low pH, oxidation stress, and toxic chemicals. Such protein responses are also helpful to understand the mechanisms of some cellular activities and the functions of some proteins.
  • Research articles
    Anaerobic treatment of fresh leachate from a municipal solid waste incinerator by upflow blanket filter reactor
    Pinjing HE, Min LI, Suyun XU, Liming SHAO,
    2009, 3(4): 404-411. https://doi.org/10.1007/s11783-009-0149-6
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    This paper describes the feasibility of fresh leachate treatment by an upflow blanket filter (UBF). Through dilution and partial effluent recycling, the organic loading rates increased from 0.51to 14.56kg COD/(m3·d), meanwhile the corresponding hydraulic retention time decreased from 9.0d to 3.6d. The reactor was able to achieve steady-state within 80d. Based on the distribution of COD fluxes in the process, it was concluded that anabolism was the main pathway of COD removal in the initial phase (1―33d), accounting for 57%―85% of total COD removed. As the anaerobic consortium of bacteria reached steady-state (after 70―86d), the majority of COD removed was transformed into methane, because the specific methane yield was close to the theoretical value (0.36L CH4/(g CODdeg)).
  • Research articles
    Comparison and modeling of two biofilm processes applied to decentralized wastewater treatment
    Guanglei QIU, Yonghui SONG, Peng YUAN, Liancheng XIANG, Jianfeng PENG, Ping ZENG,
    2009, 3(4): 412-420. https://doi.org/10.1007/s11783-009-0141-1
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    In order to control water pollution in the rapidly urbanizing South China area, biological contact oxidation (BCO) process and biological aerated filter (BAF) process were applied in a pilot-scale experiment for decentralized wastewater treatment. An investigation to find the optimal parameters of the two biofilm systems was conducted on hydraulic loading, organic loading, and aeration rate. The results indicated that the water reuse criteria required a maximum hydraulic and organic loading of 30.0 m3/(m2·d) and 4.0 kg COD/(m3·d), respectively, as well as a minimum effluent DO of 4.0 mg/L. The utilization of a new media allowed BAF to perform better than BCO. The kinetic description of the COD removal process for BAF and BCO are "Graphic", and "Graphic", respectively. The correlativity analysis showed that the two models could predict the effluent water quality based on the hydraulic retention time. Thus, the appropriate hydraulic loading for certain effluent water quality demands could be determined. The two models could be applied to wastewater treatment practice.
  • Research articles
    Response of soil microorganisms to vegetational succession in Ziwuling Forest
    Hong ZHANG, Jialong LU, Shiwei ZHAO,
    2009, 3(4): 421-427. https://doi.org/10.1007/s11783-009-0147-8
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    This study investigates the changes in soil microbial populations as vegetational succession progress from abandoned farmland to climax forest in the Ziwuling Forest, which is located in the northern part of the Loess Plateau, China. Different organic C and total extractable N between the fumigated and non-fumigated soils were assumed to be released from soil microorganisms. Soil microbial C was calculated using Kec=0.38 and microbial N was calculated using Ken=0.45. The released P was converted to microbial biomass P using Kep=0.40. Soil bacteria, fungi, and actinomycetes increased as the vegetational succession progressed. Microbial C was of the highest amount in farmland. Microbial C, N, and P generally increased from abandoned land to climax community. The results indicated significant (P<0.05) diversities of soil microbial biomass under different vegetation. There was a significant correlation between microbial biomass and soil nutrients. Knowledge about soil microbial populations is important for forecasting vegetational succession and determining the ecological condition of the environment.
  • Research articles
    Arsenic (V) removal from groundwater by GE-HL nanofiltration membrane: effects of arsenic concentration, pH, and co-existing ions
    Xiaowei WANG, Wenjun LIU, Weifang MA, Desheng LI,
    2009, 3(4): 428-433. https://doi.org/10.1007/s11783-009-0146-9
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    A laboratory-scale investigation was performed to study arsenic (As (V)) removal by negatively charged GE-HL nanofiltration (NF) membrane in simulated drinking water. Effects of As (V) concentration (0–200μg·L−1), pH, and co-ions and counter-ions were investigated. The NF membrane presented good stability, and the rejection rates exceeded 90%. The rejection rates of As (V) decreased with the increase of As (V) concentration, while it increased with the increase of pH (reached 96% at pH 6.75). Moreover, a negative relationship was observed between the co-existing ions of Cl−, Na+, SO42−, and Ca2+ and the removal of As (V), in which bivalent ions presented more significant effects than monovalent ions.
  • Research articles
    Phenanthrene sorption to environmental black carbon in sediments from the Song-Liao watershed (China)
    Jinghuan ZHANG, Mengchang HE, Chunye LIN, Ke SUN, Bin MEN, John L. ZHOU,
    2009, 3(4): 434-442. https://doi.org/10.1007/s11783-009-0150-0
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    Black carbon (BC) in ten contaminated sediments from the Song-Liao watershed, NE China, was isolated upon treatments using a combustion method at 375°C, and the isolates’ sorption isotherms for phenanthrene (Phen) were determined. All sorption isotherms were nonlinear and fitted well by the Freundlich model. A negative relation was found between Freundlich sorption nonlinearity parameter (n values) and BC/total organic carbon (TOC) content of the original sediments (r2=0.687, p<0.01), indicating the dominance of BC in Phen sorption nonlinearity. The BC isolates from this industrialized region had n values of 0.342 to 0.505 and logKFOC values of 6.02 to 6.42(μg·kg−1·OC−1)/(μg·L−1) n for Phen. At a given Ce, the BC had higher Koc value than the original sediments, revealing a higher sorption capacity for BC. BC was responsible for 50.0% to 87.3% of the total sorption at Ce=0.05 Sw, clearly indicating the dominance of BC particles in overall sorption of Phen by sediments.
  • Research articles
    BMP decision support system for evaluating stormwater management alternatives
    Mow-Soung CHENG, Jenny X. ZHEN, Leslie SHOEMAKER,
    2009, 3(4): 453-463. https://doi.org/10.1007/s11783-009-0153-x
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    Prince George’s County, Maryland, in the Washington D.C. metropolitan area has developed a best management practice decision support system (BMPDSS) to support analysis and decision making for stormwater management planning and design at both the site scale and the watershed levels. This paper presents a detailed description of the BMPDSS. A case study that demonstrates the application of the system is also included. The case study involves a Green Highway project located in a highly urbanized area within the Anacostia River watershed of the county. Several best management practices (BMP) such as bioretention, filter vegetative swale, porous paving, and landscape infiltration are proposed for reducing highway runoff and improving water quality. The BMPDSS is used to identify and evaluate various alternatives to determine the most cost-effective types and combinations of BMPs that minimize the highway runoff pollution.
  • Research articles
    Multifractal characteristics of cylindrical sludge drying
    Weiyun WANG, Aimin LI,
    2009, 3(4): 464-469. https://doi.org/10.1007/s11783-009-0040-5
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    This paper analyzes dewatered sludge drying using the multifractal theory. The drying rates of cylindrical sludge with equal masses but different cross-sectional diameters was studied, from which multifractal parameters such as partition function and quality exponent were obtained. The parameters acquired were used to calculate the multifractal singularity spectrum and indicate the presence of multifractal characteristics. The smaller cross-sectional diameters of the sludge were found to be non-homogeneous, and required quantitative methods to analyze.
  • Research articles
    Flow characteristic and wastewater treatment performance of a pilot-scale airlift oxidation ditch
    Hongtao PANG, Hanchang SHI, Huiming SHI,
    2009, 3(4): 470-476. https://doi.org/10.1007/s11783-009-0143-z
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    A pilot-scale airlift oxidation ditch using bubble diffuser and baffle as aerator was operated in a wastewater treatment plant (WWTP) to investigate its flow characteristic and wastewater treatment performance. Compared with the conventional oxidation ditch process, effective depth and oxygen utilization efficiency of this new process was improved by underwater aeration. Furthermore, it had a reversed velocity distribution, which decreased from the bottom to the top on vertical section. Velocity measurement showed that a velocity over 0.2m/s at the bottom was sufficient to prevent sludge settlement during long term operation. Application of these concepts would save land area and energy consumption by about 25%―50% and 55%, respectively. In this new system, organic biodegradation and nitrification could be well achieved. Denitrification could occur steadily in the straight part by adjusting the airflow rate. An average TN removal rate of 63% was achieved with dissolved oxygen (DO) concentrations between 0.6mg/L and 1.5mg/L. The main pollutants in the effluent could meet the strictest discharge standard (COD<50mg/L, NH4+―N<5mg/L, and TN<15mg/L) in China now.
  • Research articles
    Pilot-scale studies of domestic wastewater treatment by typical constructed wetlands and their greenhouse gas emissions
    Chaoxiang LIU, Kaiqin XU, Ryuhei INAMORI, Yuhei INAMORI, Yoshitaka EBIE, Jie LIAO,
    2009, 3(4): 477-482. https://doi.org/10.1007/s11783-009-0155-8
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    Three typical constructed wetlands (CWs) including Vertical Flow (VF), Free Water Surface (FWS), and Subsurface Flow (SF), and combined VF-SF-FWS constructed wetlands were investigated for the treatment of domestic wastewater with low C/N ratio. The performance of nutrient removal and the characteristics of greenhouse gas emissions, such as CH4 and N2O, from these CWs were compared. The results indicated that the four types of CWs had high removal efficiencies for organic matter and suspended solid (SS). The combined wetland also showed a comparatively good performance for nitrogen and phosphorus removal, and the removal efficiencies for total nitrogen (TN) and total phosphorus (TP) were 81.3% and 84.5%, respectively. The combined CWs had a comparative lower global warming potential. The FWS CW had the highest tendency to emit CH4 and led to a higher global warming potential among the four types of CWs, which was about 586 mg CO2/m2·h.
  • Research articles
    Removal of multicomponent VOCs in off-gases from an oil refining wastewater treatment plant by a compost-based biofilter system
    Dan WU, Chunyan ZHANG, Li HAO, Changjun GENG, Xie QUAN,
    2009, 3(4): 483-491. https://doi.org/10.1007/s11783-009-0144-y
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    Waste gases from oil refining wastewater treatment plants are often characterized by the presence of multicomponent and various concentrations of compounds. An evaluation of the performance and feasibility of removing multicomponent volatile organic compounds (VOCs) in off-gases from oil refining wastewater treatment plants was conducted in a pilot-scale compost-based biofilter system. This system consists of two identical biofilters packed with compost and polyethylene (PE). This paper investigates the effects of various concentrations of nonmethane hydrocarbon (NMHC) and empty bed residence time (EBRT) on the removal efficiency of NMHC. Based on the experimental results and practical applications, an EBRT of 66 s was applied to the biofilter system. The removal efficiencies of NMHC were within the range of 47%―100%. At an EBRT of 66 s, the average removal efficiency of benzene, toluene, and xylene were more than 99%, 99%, and 100%, respectively. The results demonstrated that multicomponent VOCs in off-gases from the oil refining wastewater treatment plant could be successfully removed in the biofilter system, which may provide useful information concerning the design criteria and operation of full-scale biofilters.