To investigate the influence of salinity variations on the performance of activated sludge systems, treating domestic wastewater. Methods The completely mixed reactor was used and operated in a batch-wis...To investigate the influence of salinity variations on the performance of activated sludge systems, treating domestic wastewater. Methods The completely mixed reactor was used and operated in a batch-wise mode. The activated sludge taken from the Gaobeidian Wastewater Treatment Plant was used as a seeding sludge. Total organic carbon (TOC), oxygen uptake rate (OUR) and suspended solids (SS) were used as parameters to characterize the performance of the treatment systems. TOC was measured using a TOC-analyzer (TOC-5000, Japan). The OUR value was measured with a dissolved oxygen meter (YSI model-58). SS was measured gravimetrically. Results The TOC removal efficiency and the OUR value of activated sludge were not deteriorated when the NaCl shock concentration was less than 0.5 g/L. However, when the NaCl shock concentrations were up to 10g/L and 20 g/L, the OUR of activated sludge was reduced by 35% and TOC removal efficiency was dropped by 30%, compared with the control experiment without NaCl shock loading. Conclusion The effect of NaCl shock loading on the activated sludge wastewater treatment system is dependant upon the NaCl concentrations and the degree of influence can be inferred through the change of substrate utilization rate at different shock NaCl loadings.展开更多
High salt concentrations can cause plasmolysis and loss of activity of cells, but the salt-torlerant bacterium can endure the high salt concentrations in wastewater. In this research 7 salt-torlerant bacteria, which c...High salt concentrations can cause plasmolysis and loss of activity of cells, but the salt-torlerant bacterium can endure the high salt concentrations in wastewater. In this research 7 salt-torlerant bacteria, which could survive in dry powder products and could degrade organic contaminants in saline wastewater, were isolated from a membrane bioreactor. The strain NY6 which showed the fastest growth rate, best property for organic matter degradation and could survive in dry powder more than 3 months was selected and characterized. It was classified as Bacillus aerius based on the analysis of the morphological and physiological properties as well as the 16S rRNA sequence and Neigh borjoining tree. The strain NY6 could survive in the salinity up to 6% and the optimal growth salinity is 2%; it belongs to a slightly halophilic bacterium. The capability of its dry powder products for COD removal was 800 mg COD/(g.day) in synthesized saline wastewater with salinity of 2%. According to salt-tolerant mechanism research, when the salinity was below 2%, the stain NY6 absorbed K~ and Na~ to maintain osmotic equilibrium, and when the salinity was above 2%, the NY6 kept its life by producing a large amount of spores.展开更多
In this study,the performance of 3,5-dimethyl-2,4-dichlorophenol(DCMX) degradation by a screened strain was investigated.18 S r DNA and the neighbor-joining method were used for identification of the isolated strain...In this study,the performance of 3,5-dimethyl-2,4-dichlorophenol(DCMX) degradation by a screened strain was investigated.18 S r DNA and the neighbor-joining method were used for identification of the isolated strain.The results of phylogenetic analysis and scanning electron micrographs showed that the most probable identity of the screened strain should be Penicillium sp.Growth characteristics of Penicillium sp.and degradation processes of DCMX were examined.Fourier transform infrared spectroscopy of the inoculated DCMX solution was recorded,which supported the capacity of DCMX degradation by the screened Penicillium sp.Under different salinity conditions,the highest growth rate and removal efficiency for DCMX were obtained at p H 6.0.The removal efficiency decreased from 100%to 66% when the DCMX concentration increased from 5 to 60 mg/L,respectively.Using a Box–Behnken design,the maximum DCMX removal efficiency was determined to be 98.4%.With acclimation to salinity,higher removal efficiency could be achieved.The results demonstrate that the screened Penicillium sp.has the capability for degradation of DCMX.展开更多
The integrated vertical-flow constructed wetland(IVCW) was simulated with three suits of designed experiment columns planted with Kandelia candel.Units A,B and C were irrigated with sewage of different salinity(A...The integrated vertical-flow constructed wetland(IVCW) was simulated with three suits of designed experiment columns planted with Kandelia candel.Units A,B and C were irrigated with sewage of different salinity(A:10‰ B:20‰,C:30‰),respectively.The removal rates of dissolved organic carbon(DOC),NH3-N and NO3--N dropped 90.4%-48.6%,80.2%-40.3% and 84.8%-60.9%,respectively,when salinity increases from 10‰ to 30‰.The removal rate of TP increased 14%-31.2%,oppositely.A 20-day inflow salinity drastic change shock affective trial was done on units D and E.Unit D was used as a control and irrigated with saline sewage(20‰).Unit E was irrigated with sewage with low salinity(5‰) as a salinity drastic change shock on the third and fourth days.DOC,NH3-N and NO3--N removal efficiency of unit E showed a three-stage process of change,"rapidly decrease,increase beyond the normal standard,and then back to the normal standard".TP removal value was negative during the 2-day shock period.展开更多
基金The work was supported by the National Natural Science Foundation of China (Grant No. 29637010 59978020 50325824).
文摘To investigate the influence of salinity variations on the performance of activated sludge systems, treating domestic wastewater. Methods The completely mixed reactor was used and operated in a batch-wise mode. The activated sludge taken from the Gaobeidian Wastewater Treatment Plant was used as a seeding sludge. Total organic carbon (TOC), oxygen uptake rate (OUR) and suspended solids (SS) were used as parameters to characterize the performance of the treatment systems. TOC was measured using a TOC-analyzer (TOC-5000, Japan). The OUR value was measured with a dissolved oxygen meter (YSI model-58). SS was measured gravimetrically. Results The TOC removal efficiency and the OUR value of activated sludge were not deteriorated when the NaCl shock concentration was less than 0.5 g/L. However, when the NaCl shock concentrations were up to 10g/L and 20 g/L, the OUR of activated sludge was reduced by 35% and TOC removal efficiency was dropped by 30%, compared with the control experiment without NaCl shock loading. Conclusion The effect of NaCl shock loading on the activated sludge wastewater treatment system is dependant upon the NaCl concentrations and the degree of influence can be inferred through the change of substrate utilization rate at different shock NaCl loadings.
基金supported by the National Natural Science Foundation of China (No. 51108112)the Natural Science Foundation of Heilongjiang Province (No. E201252)+2 种基金the Maixin Pathology Foundation (No. m1101)the Fundamental Research Funding of Harbin Engineering University (No. HEUFT06029)the Open Project of State Key Laboratory of Urban Water Resource Environment, Harbin Institute of Technology (No. ESK201004)
文摘High salt concentrations can cause plasmolysis and loss of activity of cells, but the salt-torlerant bacterium can endure the high salt concentrations in wastewater. In this research 7 salt-torlerant bacteria, which could survive in dry powder products and could degrade organic contaminants in saline wastewater, were isolated from a membrane bioreactor. The strain NY6 which showed the fastest growth rate, best property for organic matter degradation and could survive in dry powder more than 3 months was selected and characterized. It was classified as Bacillus aerius based on the analysis of the morphological and physiological properties as well as the 16S rRNA sequence and Neigh borjoining tree. The strain NY6 could survive in the salinity up to 6% and the optimal growth salinity is 2%; it belongs to a slightly halophilic bacterium. The capability of its dry powder products for COD removal was 800 mg COD/(g.day) in synthesized saline wastewater with salinity of 2%. According to salt-tolerant mechanism research, when the salinity was below 2%, the stain NY6 absorbed K~ and Na~ to maintain osmotic equilibrium, and when the salinity was above 2%, the NY6 kept its life by producing a large amount of spores.
基金supported by the International S&T Cooperation Program of China(No.2015DFG92750)the National Natural Science Foundation of China(Nos.51478172 and 51278464)the Natural Science Foundation of Zhejiang Province of China(No.LY17E080002)
文摘In this study,the performance of 3,5-dimethyl-2,4-dichlorophenol(DCMX) degradation by a screened strain was investigated.18 S r DNA and the neighbor-joining method were used for identification of the isolated strain.The results of phylogenetic analysis and scanning electron micrographs showed that the most probable identity of the screened strain should be Penicillium sp.Growth characteristics of Penicillium sp.and degradation processes of DCMX were examined.Fourier transform infrared spectroscopy of the inoculated DCMX solution was recorded,which supported the capacity of DCMX degradation by the screened Penicillium sp.Under different salinity conditions,the highest growth rate and removal efficiency for DCMX were obtained at p H 6.0.The removal efficiency decreased from 100%to 66% when the DCMX concentration increased from 5 to 60 mg/L,respectively.Using a Box–Behnken design,the maximum DCMX removal efficiency was determined to be 98.4%.With acclimation to salinity,higher removal efficiency could be achieved.The results demonstrate that the screened Penicillium sp.has the capability for degradation of DCMX.
基金Supported by the National High Technology Research and Development Program of China (863 Program) (2009ZX07106-002-004)the National Natural Science Foundation of China (50808172,30870221)
文摘The integrated vertical-flow constructed wetland(IVCW) was simulated with three suits of designed experiment columns planted with Kandelia candel.Units A,B and C were irrigated with sewage of different salinity(A:10‰ B:20‰,C:30‰),respectively.The removal rates of dissolved organic carbon(DOC),NH3-N and NO3--N dropped 90.4%-48.6%,80.2%-40.3% and 84.8%-60.9%,respectively,when salinity increases from 10‰ to 30‰.The removal rate of TP increased 14%-31.2%,oppositely.A 20-day inflow salinity drastic change shock affective trial was done on units D and E.Unit D was used as a control and irrigated with saline sewage(20‰).Unit E was irrigated with sewage with low salinity(5‰) as a salinity drastic change shock on the third and fourth days.DOC,NH3-N and NO3--N removal efficiency of unit E showed a three-stage process of change,"rapidly decrease,increase beyond the normal standard,and then back to the normal standard".TP removal value was negative during the 2-day shock period.