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Abbas G.,Zhejiang University | Abbas G.,University of Gujrat | Wang L.,Biogas Institute | Wang L.,Laboratory of Development and Application of Rural Renewable Energy | And 3 more authors.
Ecological Engineering

The pilot-scale internal-loop-airlift bio-particle (ILAB) reactor was a novel configuration adopted to study the performance of simultaneous partial nitrification (PN) and anaerobic ammonia oxidation (ANAMMOX). The ILAB reactor was operated at different nitrogen loading rates and hydraulic retention times to investigate the nitrogen removal kinetics. The reactor showed good tolerance to substrate concentration shock while it was significantly affected by hydraulic shock. Five kinetic models including first-order model, Grau second-order model, Stover-Kincannon model, Monod model and Contois model were applied to steady-state experimental data to evaluate the substrate removal in the reactor. The Grau second-order model and Stover-Kincannon model were found to be more appropriate compared with other models to describe and predict the performance of the reactor. Both the models were evaluated by judging the linearity between experimental data and predicted values which confirmed their validity for the process. © 2014 Published by Elsevier B.V. Source

Chen C.,Biogas Institute of Ministry of Agriculture | Zheng D.,Biogas Institute of Ministry of Agriculture | Liu G.,Biogas Institute of Ministry of Agriculture | Liu G.,Bioprocess Control AB | And 4 more authors.
Waste Management

A down plug-flow anaerobic reactor (DPAR) was designed for the feasibility study on continuous dry fermentation of swine manure without any additional stirring. Using fresh swine manure as the feedstock with TS concentration (w/w) of 20%, 25%, 30%, and 35%, stable volumetric biogas production rates of 2.40, 1.92, 0.911, and 0.644L·(Ld)-1 and biogas yields of 0.665, 0.532, 0.252, and 0.178Lg-1VS were obtained respectively, and the TS degradation rates were 46.5%, 45.4%, 53.2%, and 55.6%, respectively. With the increase of feedstock TS concentration, the concentration of ammonia nitrogen grew up to the maximum value of 3500mgL-1. Biogas production was obviously inhibited when the concentration of ammonia nitrogen was above 3000mgL-1. The maximal volumetric biogas production rate of 2.34L·(Ld)-1 and biogas yield of 0.649Lg-1VS were obtained with TS concentration of 25% at 25°C without inhibition. Liquidity experiments showed that TS concentration of digestate could be less than 15.8%, and the flow rate of digestate more than 0.98ms-1 when the feedstock TS concentration was less than 35%, which indicated the digestate could be easily discharged from a DPAR. Therefore, it is feasible to conduct a continuous dry fermentation in a DPAR using fresh swine manure as the feedstock with TS concentration less than 35%, whereas the feedstock TS concentration should not exceed 30% to achieve the maximal biogas production rate and biogas yield. © 2015 Elsevier Ltd. Source

Wang X.M.,Central China Normal University | Ma S.,Biogas Institute of Ministry of Agriculture | Ma S.,Laboratory of Development and Application of Rural Renewable Energy | Yang S.Y.,Central China Normal University | And 3 more authors.
International Journal of Systematic and Evolutionary Microbiology

A Gram-stain-positive, non-motile, aerobic and terminal-endospore-forming rod-shaped bacterium, strain P5-1T, was isolated from the hindgut of a wood-feeding higher termite, Nasutitermes sp. Phylogenetic analysis of 16S rRNA gene sequences showed that the strain was closely related to Paenibacillus sepulcri CCM 7311T (97.5% similarity). Growth was observed at 10–40 °C (optimum, 30 °C) and at pH 5.5–9.0 (optimum, pH 7.5). The DNA G+C content of strain P5-1T was 48.9 mol%. Cells contained menaquinone 7 (MK-7) as the sole respiratory quinone and the major fatty acids were anteiso-C15: 0 and iso-C15: 0. The cellular polar lipids comprised phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid, one unidentified glycolipid and one unidentified aminophospholipid. The diamino acid of the cell-wall peptidoglycan was mesodiaminopimelic acid. Based on the phylogenetic, chemotaxonomic and phenotypic data obtained within this study, strain P5-1T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus nasutitermitis sp. nov. is proposed. The type strain is P5-1T (=CGMCC 1.15178T=NBRC 111536T). © 2015 IUMS Printed in Great Britain. Source

Lan G.,Southwest Petroleum University | Lan G.,Laboratory of Development and Application of Rural Renewable Energy | Fan Q.,Southwest Petroleum University | Liu Y.,University of Southampton | And 4 more authors.
Biochemical Engineering Journal

The present work aims to produce rhamnolipid from waste cooking oil (WCO) using a newly isolated bacterium named Pseudomonas SWP-4. SWP-4 was a high-yield strain that could accumulate rhamnolipid steadily even in decline phase and gave a maximum rhamnolipid yield of 13.93. g/L and WCO utilization percent around 88%. The critical micelle concentration of the produced rhamnolipid was only 27. mg/L and its emulsification index against n-hexadecane reached around 59%. Moreover, it reduced the surface tension of water from 71.8. mN/m to 24.1. mN/m and the interfacial tension against n-hexadecane from 29.4. mN/m to 0.9. mN/m. Results of biosurfactant stability show the rhamnolipid was effective when the salinity was lower than 8% and pH value ranged from 4 to 10, and it was quite thermostable based on thermal gravity analysis. Furthermore, it maintained high surface activity even after incubation under extreme conditions i.e., pH of 4.0, salinity of 8% and temperature of 80. °C for half a month. Based on free fatty acids metabolism analysis, Pseudomonas SWP-4 consumed palmitic acid, oleic acid and linoleic acid chiefly. All these characteristics demonstrate bioconversion and biodegradation of WCO by Pseudomonas SWP-4 is a promising and commercial way of rhamnolipid production and waste treatment. © 2015 Elsevier B.V. Source

Yang D.,Biogas Institute of Ministry of Agriculture | Yang D.,Laboratory of Development and Application of Rural Renewable Energy | Deng L.,Biogas Institute of Ministry of Agriculture | Deng L.,Laboratory of Development and Application of Rural Renewable Energy | And 8 more authors.

Swine wastewater was separated into a solid fraction and a liquid fraction in a biogas plant using a separator with hydraulic wedge-shaped sieve. The liquid fraction (separated slurry) was further separated into concentrated slurry and dilute liquid by gravity sedimentation in the laboratory. Components and methane production of the solid fraction accounted for about 15% of those of the raw wastewater. The majority of the organic matter and phosphorus (more than 60%) were distributed in the concentrated slurry. The concentrated slurry represented 15% of the volume of initial wastewater but produced more than 70% of the total methane production. The condensation of the pollutants and nutrients in the concentrated slurry can facilitate land application of digestate. The dilute liquid with less organic matter and nutrients can be treated easily using less expensive and easier treatment options. © 2014 Elsevier Ltd. All rights reserved. Source

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