Four pure cultures were isolated from soil samples potentially contaminated with gasoline compounds either at a construction site near a gas station in Fai Chi Kei,Macao SAR or in the northern parts of China（Beijing,...Four pure cultures were isolated from soil samples potentially contaminated with gasoline compounds either at a construction site near a gas station in Fai Chi Kei,Macao SAR or in the northern parts of China（Beijing,and Hebei and Shandong）.The effects of different concentrations of benzene,toluene,ethylbenzene,and three isomers（ortho-,meta-,and para-） of xylene（BTEX）,total petroleum hydrocarbons（TPH）,and trichloroethylene（TCE）,when they were present in mixtures,on the bio-removal effciencies of microbial isolates were investigated,together with their interactions during the bio-removal process.When the isolates were tested for the BTEX（50-350 mg/L）/TPH（2000 mg/L） mixture,BTEoX in BTEoX/TPH mixture was shown with higher bio-removal effciencies,while BTEmX in BTEmX/TPH mixture was shown with the lowest,regardless of isolates.The TPH in BTEmX/TPH mixture,on the other hand,were generally shown with higher bio-removal effciencies compared to when TPH mixed with BTEoX and BTEpX.When these BTEX mixtures（at 350 mg/L） were present with TCE（5-50 mg/L）,the stimulatory effect of TCE toward BTEoX bio-removal was observed for BTEoX/TCE mixture,while the inhibitory effect of TCE toward BTEmX for BTEmX/TCE mixture.The bio-removal effciency for TPH was shown lower in TPH（2000 mg/L）/TCE（5-50 mg/L） mixtures compared to TPH present alone,implying the inhibitory effect of TCE toward TPH bio-removal.For the mixture of BTEX（417 mg/L）,TPH（2000 mg/L） along with TCE（5- 50 mg/L）,TCE was shown co-metabolically removed more effciently at 15 mg/L,probably utilizing BTEX and/or TPH as primary substrates.展开更多
A self-made anaerobic bio-filter bed which was inoculated with special sludge showed high efficiency in removing hexavalent chromium. When pump flow was 47 ml/min and CODCr of wastewater was about 140 mg/L, it took 4 ...A self-made anaerobic bio-filter bed which was inoculated with special sludge showed high efficiency in removing hexavalent chromium. When pump flow was 47 ml/min and CODCr of wastewater was about 140 mg/L, it took 4 h to decrease the Cr6+ concentrations from about 60 mg/L to under 0.5 mg/L, compared with 14 h without carbon source addition. Cr6+ concentra- tions ranged from 64.66 mg/L to 75.53 mg/L, the system efficiency was excellent. When Cr6+ concentration reached 95.47 mg/L, the treatment time was prolonged to 7.5 h. Compared with the contrast system, the system with trace metals showed clear supe- riority in that the Cr6+ removal rate increased by 21.26%. Some analyses also showed that hexavalent chromium could probably be bio-reduced to trivalent chromium, and that as a result, the chrome hydroxide sediment was formed on the surface of microor- ganisms.展开更多
Algae and cyanobacteria are known to be able to remove a variety of pollutants from water,including toxic metal ions.In this study,algal and cyanobacterial species growing in two polluted water bodies were identified,...Algae and cyanobacteria are known to be able to remove a variety of pollutants from water,including toxic metal ions.In this study,algal and cyanobacterial species growing in two polluted water bodies were identified,and the Pb(Ⅱ)removal ability of these isolated species was investigated.Based on microscopic observations,27 species were identified,and nine species were isolated as pure cultures.Pb(Ⅱ)bioremediation of five selected species(Anacystis sp.,Chlorella sp.1,Monoraphidium sp.,Phormidium sp.,and Uronema sp.)was studied in detail.The mean Pb(Ⅱ)removal abilities varied among these five species:Phormidium sp.>Monoraphidium sp.>Uronema sp.>Chlorella sp.1>Anacystis sp.The Pb(Ⅱ)tolerance of each species was determined based on the live cell percentage and biofilm formation capacity.Within a period of 3 d,Phormidium sp.,Monoraphidium sp.,and Uronema sp.showed nearly 90%of survival,and all five species demonstrated biofilm formation capacities exceeding 50%.Furthermore,the Pb(Ⅱ)removal ability of the five species exhibited a strong positive correlation with the live cell percentage and showed a strong negative correlation with the biofilm formation capacity.In conclusion,Phormidium sp.,Monoraphidium sp.,and Uronema sp.exhibited high tolerances towards Pb(Ⅱ)and presented high removal abilities.Thus,these species can be identified as potential sorbents for development of suitable adsorption systems to remove Pb(Ⅱ)from aqueous solutions.展开更多
基金supported by the University of Macao Research Committee and the Macao Science and Technology Development Fund
文摘Four pure cultures were isolated from soil samples potentially contaminated with gasoline compounds either at a construction site near a gas station in Fai Chi Kei,Macao SAR or in the northern parts of China（Beijing,and Hebei and Shandong）.The effects of different concentrations of benzene,toluene,ethylbenzene,and three isomers（ortho-,meta-,and para-） of xylene（BTEX）,total petroleum hydrocarbons（TPH）,and trichloroethylene（TCE）,when they were present in mixtures,on the bio-removal effciencies of microbial isolates were investigated,together with their interactions during the bio-removal process.When the isolates were tested for the BTEX（50-350 mg/L）/TPH（2000 mg/L） mixture,BTEoX in BTEoX/TPH mixture was shown with higher bio-removal effciencies,while BTEmX in BTEmX/TPH mixture was shown with the lowest,regardless of isolates.The TPH in BTEmX/TPH mixture,on the other hand,were generally shown with higher bio-removal effciencies compared to when TPH mixed with BTEoX and BTEpX.When these BTEX mixtures（at 350 mg/L） were present with TCE（5-50 mg/L）,the stimulatory effect of TCE toward BTEoX bio-removal was observed for BTEoX/TCE mixture,while the inhibitory effect of TCE toward BTEmX for BTEmX/TCE mixture.The bio-removal effciency for TPH was shown lower in TPH（2000 mg/L）/TCE（5-50 mg/L） mixtures compared to TPH present alone,implying the inhibitory effect of TCE toward TPH bio-removal.For the mixture of BTEX（417 mg/L）,TPH（2000 mg/L） along with TCE（5- 50 mg/L）,TCE was shown co-metabolically removed more effciently at 15 mg/L,probably utilizing BTEX and/or TPH as primary substrates.
基金Project (No. 020099) supported by a Grant from EnvironmentalProtection Bureau of Guangdong Province, China
文摘A self-made anaerobic bio-filter bed which was inoculated with special sludge showed high efficiency in removing hexavalent chromium. When pump flow was 47 ml/min and CODCr of wastewater was about 140 mg/L, it took 4 h to decrease the Cr6+ concentrations from about 60 mg/L to under 0.5 mg/L, compared with 14 h without carbon source addition. Cr6+ concentra- tions ranged from 64.66 mg/L to 75.53 mg/L, the system efficiency was excellent. When Cr6+ concentration reached 95.47 mg/L, the treatment time was prolonged to 7.5 h. Compared with the contrast system, the system with trace metals showed clear supe- riority in that the Cr6+ removal rate increased by 21.26%. Some analyses also showed that hexavalent chromium could probably be bio-reduced to trivalent chromium, and that as a result, the chrome hydroxide sediment was formed on the surface of microor- ganisms.
基金supported by the University of Peradeniya,Sri Lanka(Grant No.URG/2016/50/S).
文摘Algae and cyanobacteria are known to be able to remove a variety of pollutants from water,including toxic metal ions.In this study,algal and cyanobacterial species growing in two polluted water bodies were identified,and the Pb(Ⅱ)removal ability of these isolated species was investigated.Based on microscopic observations,27 species were identified,and nine species were isolated as pure cultures.Pb(Ⅱ)bioremediation of five selected species(Anacystis sp.,Chlorella sp.1,Monoraphidium sp.,Phormidium sp.,and Uronema sp.)was studied in detail.The mean Pb(Ⅱ)removal abilities varied among these five species:Phormidium sp.>Monoraphidium sp.>Uronema sp.>Chlorella sp.1>Anacystis sp.The Pb(Ⅱ)tolerance of each species was determined based on the live cell percentage and biofilm formation capacity.Within a period of 3 d,Phormidium sp.,Monoraphidium sp.,and Uronema sp.showed nearly 90%of survival,and all five species demonstrated biofilm formation capacities exceeding 50%.Furthermore,the Pb(Ⅱ)removal ability of the five species exhibited a strong positive correlation with the live cell percentage and showed a strong negative correlation with the biofilm formation capacity.In conclusion,Phormidium sp.,Monoraphidium sp.,and Uronema sp.exhibited high tolerances towards Pb(Ⅱ)and presented high removal abilities.Thus,these species can be identified as potential sorbents for development of suitable adsorption systems to remove Pb(Ⅱ)from aqueous solutions.
