Wei Ding

Zhejiang University, Hangzhou, Zhejiang Sheng, China

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Publications (6)10.55 Total impact

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    ABSTRACT: An aerobic denitrifier was isolated from the Hua-Jia-Chi pond in China and identified as Pseudomonas mendocina 3-7 (Genbank No. HQ285879). This isolated strain could express periplasmic nitrate reductase which is essential for aerobic denitrification occurred when the dissolved oxygen (DO) level maintains at 3-10 mg L(-1). To determine whether the ability of isolated strain is exhibited in the bioremediation of polluted drinking source water, the heterotrophic nitrification and aerobic denitrification characteristics of P. mendocina 3-7 under different cultural conditions such as oxygen level, nitrate and organic concentrations were studied from the nitrogenous balance in the paper. By measuring the nitrogen balance in all experiments under different culture conditions, the removal of total organic carbon and ammonium was positively correlated with total nitrogen removal, especially under high substrate level. With substrate concentration decreasing, ammonium and nitrate removal occurred separately, and ammonium was completely utilized first under low substrate concentration. Compared to that under high substrate level, the specific growth rate of P. mendocina 3-7 was not low under the low substrate level and the pollutant removal efficiencies remained high, which implies the stronger nitrogen removal and acclimatization capacities of the strain in oligotrophic niches.
    Environmental Science and Pollution Research 03/2012; 19(8):3185-91. · 2.76 Impact Factor
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    ABSTRACT: In recent years, nitrogen pollution has been increasingly serious in environmental waters in China, especially in drinking source. Seven predominant aerobic denitrifiers were isolated and characterized from the oligotrophic ecosystems. Based on their phenotypic and phylogenetic characteristics, the isolates were identified as the genera of Pseudomonas, Achromobacter and Acinetobacter, and all isolates could express periplasmic nitrate reductase which was essential for the aerobic denitrification. The growth rates of the isolates were at 0.30-0.83 h(-1), and obvious denitrification occurred when the dissolved oxygen (DO) level maintained at 3-10 mg L(-1). The isolates were able to conduct heterotrophic nitrification for realizing completely nitrogen removal in aerobic oligotrophic niche. Furthermore, three strains especially Pseudomonas sp.3-7 showed outstanding capacities of extracellular polymeric substances (EPS) secretion and aggregation. Results demonstrated that the isolation of aerobic denitrifiers favored the bioremediation of oligotrophic ecosystems.
    Bioresource Technology 03/2012; 108:1-7. · 5.04 Impact Factor
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    ABSTRACT: The start-up pattern of biofilm remediation system affects the biofilm characteristics and operating performances. The objective of this study was to evaluate the performances of the contaminated source water remediation systems with different start-up patterns in view of the pollutants removal performances and microbial community succession. The operating performances of four lab-scale simulated river biofilm reactors were examined which employed different start-up methods (natural enrichment and artificial enhancement via discharging sediment with influent velocity gradient increase) and different bio-fillers (Elastic filler and AquaMats® ecobase). At the same time, the microbial communities of the bioreactors in different phases were analyzed by polymerase chain reaction, denaturing gradient gel electrophoresis, and sequencing. The pollutants removal performances became stable in the four reactors after 2 months' operation, with ammonia nitrogen and permanganate index (COD(Mn)) removal efficiencies of 84.41-94.21% and 69.66-76.60%, respectively. The biomass of mature biofilm was higher in the bioreactors by artificial enhancement than that by natural enrichment. Microbial community analysis indicated that elastic filler could enrich mature biofilm faster than AquaMats®. The heterotrophic bacteria diversity of biofilm decreased by artificial enhancement, which favored the ammonia-oxidizing bacteria (AOB) developing on the bio-fillers. Furthermore, Nitrosomonas- and Nitrosospira-like AOB coexisted in the biofilm, and Pseudomonas sp., Sphaerotilus sp., Janthinobacterium sp., Corynebacterium aurimucosum were dominant in the oligotrophic niche. Artificial enhancement via the combination of sediment discharging and influent velocity gradient increasing could enhance the biofilm formation and autotrophic AOB enrichment in oligotrophic niche.
    Environmental Science and Pollution Research 11/2011; 19(5):1584-93. · 2.76 Impact Factor
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    ABSTRACT: Aiming at the carbon source limitation of denitrification in oligotrophic habitat, this paper studied the effects of intermittent aeration on the nitrogen-removal capability of biological contact oxidation remediation system for micro-polluted source water, and approached the feasibility and process mechanism of shortcut nitrification and denitrification in the system. Under the condition of 8 h-16 h anoxic-aerobic phase (I), the remediation system performed stably, and its average removal efficiency of ammonium (NH4+ -N), permanganate index (COD(Mn)), and total nitrogen (TN) was 93.0%, 78.1%, and 19.4%, respectively. Under the condition of 16 h-8 h anoxic-aerobic phase (II), the NH4+ -N and COD(Mn) removal efficiency still maintained at 81.2% and 76.4%, respectively, the accumulation of nitrite (NO2- -N) was significant, and the removal efficiency of TN reached more than 50%. The nitrogen transformation characteristics in the system during a cycle under condition II demonstrated that at the prerequisite of effluent NH4+ -N and DO concentrations reaching the standards, shortening aerobic phase length could maintain the DO concentration at 0. 5 -1.5 mg L(-1) in a long term, inhibit the growth and activity of nitrite-oxidizing bacteria, and thereby, NO2- -N had an obvious accumulation, and the nitrogen removal via shortcut nitrification-denitrification in the biological contact oxidation remediation system for micro-polluted source water was finally achieved.
    Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 04/2011; 22(4):1027-32.
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    ABSTRACT: Two simulated river bioreactors with elastic filler and AquaMats were applied to remediate micro-polluted source water. Under intermittent aeration and gradual increase of aeration intensity, the biofilm reactor with elastic filler was successful start-up within 50 days, and average removal efficiencies of permanganate index, NH4(+) -N were 78.2% and 93.5%, respectively, but the removal efficiencies of the reactor with AquaMats were more than 70% and 80% after two weeks. On the condition of aerobic to anoxic ratio of 3 h: 3 h and aeration intensity of 250 L x h(-1), elastic filler was more efficient for the removal of permanganate index, NH4(+) -N, TN and TP. The pollutant removal of AquaMats was strongly enhanced when the aerobic to anoxic ratio and aeration intensity changed to 2 h :4 h and 120 L x h(-1), which suggested its potential of energy saving. Microscopic observation revealed that the surface of elastic filler was fully surrounded with filamentous bacteria and more inorganic particulate matter after successful start-up of the reactor, and the biofilm attaching to AquaMats was of higher microbial population diversity. The results indicated that elastic filler with homogeneous biofilm had a strong retention capacity for its radial structure, and the AquaMats with microporous structure was more suitable for the enrichment of different functional microorganisms and enhanced the collaborative removal of multiple pollutants.
    Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 11/2010; 31(11):2639-44.
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    ABSTRACT: The catalytic ozonation of industrial wastewater containing chloro and nitro aromatic compounds was carried out in a semi-continuous lab-scale reactor using Mn/Co modified porous diatomaceous ceramic fillings as catalysts. Results showed that the Mn/Co modified filling significantly enhanced the removal efficiencies of TOC and COD, as well as the ozone utilization efficiency over non-catalytic ozonation. A closer of scrutiny of catalytic ozonation system at neutral pH found that almost complete decolorization and removal of chloro and nitro pollutants were achieved after 80 min reaction time. A sharp decrease in pH and TOC and the formation of high concentrations of nitrate and chloride were observed at initial stage of ozonation. The effect of catalytic ozonation was evaluated on the subsequent biological treatment through biodegradability and acute toxicity tests. Catalytic ozonation significantly increased the biodegradability of industrial wastewater in company with toxicity reduction. Thus using coupled catalytic ozonation-sequencing batch reactor under neutral condition may be efficient and cost-effective in treating the wastewater.
    Desalination. 01/2010;