Papers by Author: Li Wei

Abstract: In this study, IC anaerobic reactor was made to deal with the wastewater with high-concentration sulfate, the sludge from sewage treatment plant was put into two cells of IC reactor to domesticate sulfur-reducing bacteria (SRB), artificial water was made to simulate the wastewater with high-concentration SO₄²⁻. In order to remove the SO₄²⁻ efficiently, two stages were designed in this study: sludge domestication stage and concentration strengthening stage. In sludge domestication stage, SRB could grow normally, the removal rate of SO₄²⁻ was between 34.14% and 36.2%;in concentration strengthening stage, removal rate of SO₄²⁻ was between 26% and 26.86%,demonstrating that SRB could grow and remove SO₄²⁻ in such high-concentration SO₄²⁻( 38000 mg/L ) wastewater.

Abstract: Most Oilfield of China has been a stage of Oil recovery with high water, microbial residual oil gasification technology as the oilfield's reserves technology has a good application prospect, especially the use of microorganisms for gasification of residual oil. The study has far-reaching significance, and it mainly turns the difficult mining oil reservoir into natural gas (mainly methane) through microbial degradation. It is the most effective, economical and environment-friendly way to enhance oil recovery efficiency and to extend the reservoir life. This paper summarized the relevant principles of oil microbial degradation and gasification, microbial enhanced oil recovery and Residual oil gasification at home and abroad, and come up with a few new research ideas.

Abstract: Methanogens are important environmental microbial and play an important role in the nature of the carbon-cycling, its unique physiological characteristics and metabolic mechanisms make it play an indispensable role in environmental protection and energy field. At present, known methane biosynthesis has three pathways: acetic acid, H/CO₂, methyl compound as the substrates generate methane through different reaction. Ecological factor affecting methanogens are mainly temperature, pH value, redox potential, etc. In this paper, we carry on analyzing the research progress of the methanogens species, its physiological characteristics, metabolic pathway, ecological factor and industrial application, and propose methods and the thinking of study to improve methane gas production by adjusting the ecological factor as the control factor.

Abstract: A Gram-positive, strictly aerobic and moderately halophilic bacterial strain HSD was obtained from the sea water sample collected from International Sea Water Bathing Place in Weihai, a city on the shore of the Yellow Sea. Strain HSD was bacillus. The optimum growth temperature was 32~37°C and the optimum pH was 6.0~9.0. It could grow well at 100 g•L-1 salt mass concentration. The G+C mole fraction of its genomic DNA was 37.5%. 16S rRNA gene sequence indicated a close relationship to Alkalibacillus halophilus (DQ359731) with similarity of 99%. However, they had obvious difference in whole-cell main fatty acid components, cell size, cell morphology, motility, oxidase, gelatine liquefication, nitrate reduction, NaCl tolerance range, pH tolerance range, G+C mole fraction, sole carbon source, sole nitrogen source, antibiotic sensitivity and a source of the strain isolation. Comparing of these taxonomic characters of strain HSD with those of other type strains of the genus Alkalibacillus, the differences were more obvious. In view of multiple identification results, it was proposed that strain HSD was classified as the type strain of a new species of the genus Alkalibacillus under the name Alkalibacillus huanghaiensis sp.nov..

Abstract: A Gram-positive, strictly aerobic, spore-bearing and moderately halophilic bacterial strain HNPHT was obtained from the sea mud sample collected from Jinhaitan Park in Weihai, a city on the shore of the Yellow Sea. Strain HNPHT was bacillus. The optimum growth temperature was 30-36°C and the optimum pH was 6.5-9.5. It could grow well at 5-20% salt concentration. The G+C content of its genomic DNA was 37.0%. 16S rRNA gene sequence indicated a close relationship to Alkalibacillus halophilus (DQ359731) and Alkalibacillus salilacus (AY671976) with similarity of 99%. However, they had obvious difference in whole-cell main fatty acid components, cell size, cell morphology, colony color, motility, oxidase, gelatine liquification, nitrate reduction, NaCl tolerance range, pH tolerance range, G+C mole fraction, sole carbon source, sole nitrogen source, antibiotic sensitivity and a source of the strain isolation. A comparison of these taxonomic characters of strain HNPHT with those of some type strains of the genus Alkalibacillus indicated that the strain could be distinguished from A. halophilus and A. salilacus. In view of multiple identification results, it was proposed that strain HNPHT was classified as the type strain of a new species of the genus Alkalibacillus under the name Alkalibacillus weihaiensis sp. nov..

Abstract: The collection and utilization of urban rainwater is currently a substantial measure of ecological construction in the city which covers a variety of technologies used and reflected in the multi-dimensional overlap with the urban space. By analyzing the current trends in related technology in the world, the paper probes the organic integration of rainwater collected system with urban spatial structure and elements in a view of overall optimization. Then the paper proposes to set up the coupled design pattern for urban rainwater recycling system in a way of district division, facility grading and rainwater classification according to the characteristics of land use mode and urban planning frame.

Abstract: We isolated flocculants-producing bacteria F2 from soil. It shows high and stable flocculating activity for Kaolin clay suspension. In order to increase yield of flocculants, we need determine the optimal obtained time. We measured the changes of several parameters using shaking flask experiment, including flocculating- rate, the content of polysaccharide, protein and glucose. It’s showed that the optimal obtained time of bio-flocculants is 21 h. And we built the model about the production of bio-flocculants. Through the comparison of experimental data and the corresponding calculated values from the models, we found that the data joint well and the model can provide theoretical basis for Industrialization of bio-flocculants.

Abstract: Kinetic equations of soluble components are analyzed in an anaerobic/ anoxic sequencing batch reactor (A/A SBR) enriched with denitrifying phosphorus removing bacteria (DPB) sludge. Mathematical model is established for denitrifying phosphorus removal process. The model is based on the simplification of the metabolic model for biological phosphorus removal by DPB. A proper set of kinetic parameters was calculated from the data obtained in the batch tests. The model was subsequently applied for the simulation of cycle behavior of soluble components in the A/A SBR. The results of the simulation indicated that the model can predict the concentration of each component for denitrifying phosphorus removal successfully.

Abstract: To improve the efficiency of petrochemical wastewater treatment, a hybrid system with both attached and suspended biomass was proposed to replace the existing biofilm process. According to the performances of the hybrid system, the optimal suspended biomass concentration in the tank was determined around 1000 mg/L. When the average influent COD and NH4+-N concentration were 395.7 mg/L and 13.5 mg/L, the according removal efficiencies of the hybrid system were up to 84% and 69%, compared to 74% and 20% when operated with the biofilm system. The GC-MS analysis showed that both the amounts and types of refractory organics in the effluent of hybrid system were greatly reduced when compared with those of the previous biofilm process. The foaming problem was also resolved along with the enhanced pollutants removal efficiency. The hybrid process was an economic and feasible alternative for petrochemical wastewater treatment, which ensured carbonaceous oxidation, nitrification and decomposition of refractory substances.

Abstract: The microbial fuel cell (MFC) constructed by a modified Continuous Stirred Tank Reactor (CSTR) which was used as acidification-phase of two-phase anaerobic digestion system. The experiment was operated as batch mode at mesophilic condition (35°C) to evaluate continue voltage output using cattle dung as substrate in hydrolysis-acidification process. The results illustrated that electricity generation increased noticeably to 300mV after 3 days operation, reached 430mV after 20 days and stabilized electricity generation from 420mV to 470mV in the following 70 days. The pH decreased from 7.15 to 6.65 after 15 days operation and maintained stability from 6.4 to 6.8. The main components of VFA in anode chamber were acetic, propionic and butiric acids. The dominating VFA was acetic acid that predominated untile day 50 and the maximum propionic acid concentration was 15% of total VFA.