[Objective] This study aimed to screen a bacterial strain capable of producing bioflocculant. [Method] A bacterial strain T-11 capable of producing bioflocculant was isolated from activated sludge. Detailed tests on t...[Objective] This study aimed to screen a bacterial strain capable of producing bioflocculant. [Method] A bacterial strain T-11 capable of producing bioflocculant was isolated from activated sludge. Detailed tests on the morphological, physiological and biochemical characteristics were carried out and identification was performed to identify the strain. Finally, the bioflocculant was isolated and purified, and the flocculating activity and chemical characteristics were measured. [Result] It was identified as Serratia plumuthica based on its morphological, physiological and biochemical characteristics. This strain secreted flocculant best in a culture medium which included sucrose and NaNO3. The maximal cell growth was achieved within 10 h and the flocculating activity paralleled to it. It was found to be effective for flocculation of kaolin suspension, when added at a final concentration of 0.7 mg/L, over a range of pHs （2-7）, and temperature （approximately 30-80 ℃）. Chemical analysis indicated that the bioflocculant was an acidic polysaccharide consisting of glucose, glucuronic acid and galactose, talose and altrose. Infrared spectrum analysis also revealed typical characteristics of polysaccharides. [Conclusion] The biofloccu- lants produced by strain T-11 can greatly improve the ability of activated sludge to settle.展开更多
In order to describe the relationship between dynamic process and sludge removing load in active sludge system, a new method for designing the volume of aeration tanks was put forward based on the Michaelis and Menten...In order to describe the relationship between dynamic process and sludge removing load in active sludge system, a new method for designing the volume of aeration tanks was put forward based on the Michaelis and Menten equation. the influence of sludge returning was considered in the design. The result shows that the parameter of sludge reflux ratio plays a very important role in the design of active sludge system. In some given conditions,there exists an optimum reflux ratio which can make the volume of aeration tank be the minimum.展开更多
Methomyl, an extremely toxic pesticide, is widely used in agriculture. A strain named mdw-1 capable of degrading methomyl rapidly was successfully isolated from activated sludge in this study. It could utilize methomy...Methomyl, an extremely toxic pesticide, is widely used in agriculture. A strain named mdw-1 capable of degrading methomyl rapidly was successfully isolated from activated sludge in this study. It could utilize methomyl as the sole carbon or nitrogen source. The optimal temperature and medium pH for its growth and methomyl biodegradation were 30℃ and 7.0, respectively. It was identified as a Paracoccus sp. according to its morphological features, physiological and biochemical characteristics, and phylogenetic analysis based on the sequence of 16S rDNA. Gas chromatography-mass spectrometry （GC-MS） analysis showed that methomyl could be completely transformed to S-methyl-N-hydroxythioacetamidate in 10 h of incubation with the isolate mdw-1.展开更多
Biodegradation of representative nonylphenol ethoxylates, NP10EO, was investigated in the continuous flow activated sludge simulation test; the effect of hydraulic retention time （HRT） on its biodegradation was exam...Biodegradation of representative nonylphenol ethoxylates, NP10EO, was investigated in the continuous flow activated sludge simulation test; the effect of hydraulic retention time （HRT） on its biodegradation was examined. The primary biodegradation degree of NP10EO was 96.5% at 3 hours hydraulic retention time and 96.2% at 6 hours hydraulic retention time; the ultimate biodegradation degree, which was 84.8% and 87.3%, respectively, indicated that the primary biodegradation of NP10EO was very easy and most NP10EO can be biodegraded ultimately, the prolonging of HRT had no infuence on the primary biodegradation and little infuence on the ultimate biodegradation. The possible biodegradation pathways of NPnEO, especially the biodegradation pathways of benzene ring in NPnEO, were proposed through Electrospray ionization-mass spectrometry analysis.展开更多
基金Supported by the Science Research Project of Qingdao Technical College in 2012(12-A-2)~~
文摘[Objective] This study aimed to screen a bacterial strain capable of producing bioflocculant. [Method] A bacterial strain T-11 capable of producing bioflocculant was isolated from activated sludge. Detailed tests on the morphological, physiological and biochemical characteristics were carried out and identification was performed to identify the strain. Finally, the bioflocculant was isolated and purified, and the flocculating activity and chemical characteristics were measured. [Result] It was identified as Serratia plumuthica based on its morphological, physiological and biochemical characteristics. This strain secreted flocculant best in a culture medium which included sucrose and NaNO3. The maximal cell growth was achieved within 10 h and the flocculating activity paralleled to it. It was found to be effective for flocculation of kaolin suspension, when added at a final concentration of 0.7 mg/L, over a range of pHs （2-7）, and temperature （approximately 30-80 ℃）. Chemical analysis indicated that the bioflocculant was an acidic polysaccharide consisting of glucose, glucuronic acid and galactose, talose and altrose. Infrared spectrum analysis also revealed typical characteristics of polysaccharides. [Conclusion] The biofloccu- lants produced by strain T-11 can greatly improve the ability of activated sludge to settle.
文摘In order to describe the relationship between dynamic process and sludge removing load in active sludge system, a new method for designing the volume of aeration tanks was put forward based on the Michaelis and Menten equation. the influence of sludge returning was considered in the design. The result shows that the parameter of sludge reflux ratio plays a very important role in the design of active sludge system. In some given conditions,there exists an optimum reflux ratio which can make the volume of aeration tank be the minimum.
基金Project supported by the National Natural Science Foundation of China(No.30600016)the National High Technology Research and Development Program of China(863 Program)(No.2007AA10Z405)+2 种基金the National Program for Sci-Tech Basic Platform Construction of China(No.2005DKA21201-2)the Program for Science and Technology Development ofJiangsu Province,China(No.BE2008669)the Program for Integration of Production,Education,and Research of Guangdong Province and Ministry of Education,China(No.2006090204007)
文摘Methomyl, an extremely toxic pesticide, is widely used in agriculture. A strain named mdw-1 capable of degrading methomyl rapidly was successfully isolated from activated sludge in this study. It could utilize methomyl as the sole carbon or nitrogen source. The optimal temperature and medium pH for its growth and methomyl biodegradation were 30℃ and 7.0, respectively. It was identified as a Paracoccus sp. according to its morphological features, physiological and biochemical characteristics, and phylogenetic analysis based on the sequence of 16S rDNA. Gas chromatography-mass spectrometry （GC-MS） analysis showed that methomyl could be completely transformed to S-methyl-N-hydroxythioacetamidate in 10 h of incubation with the isolate mdw-1.
文摘Biodegradation of representative nonylphenol ethoxylates, NP10EO, was investigated in the continuous flow activated sludge simulation test; the effect of hydraulic retention time （HRT） on its biodegradation was examined. The primary biodegradation degree of NP10EO was 96.5% at 3 hours hydraulic retention time and 96.2% at 6 hours hydraulic retention time; the ultimate biodegradation degree, which was 84.8% and 87.3%, respectively, indicated that the primary biodegradation of NP10EO was very easy and most NP10EO can be biodegraded ultimately, the prolonging of HRT had no infuence on the primary biodegradation and little infuence on the ultimate biodegradation. The possible biodegradation pathways of NPnEO, especially the biodegradation pathways of benzene ring in NPnEO, were proposed through Electrospray ionization-mass spectrometry analysis.
