Geosmin is one of the major causative compounds of earthy-musty odor and taste (off-flavor) in drinking water (lakes) and in farmed fish. In this study, the sorption of cyclodextrin polymers (CDPs) towards geosmin in ...Geosmin is one of the major causative compounds of earthy-musty odor and taste (off-flavor) in drinking water (lakes) and in farmed fish. In this study, the sorption of cyclodextrin polymers (CDPs) towards geosmin in aqueous solution was investigated. Sorption kinetics, the effect of solution pH and contact time on the sorption capability of α-, β- and γ-cyclodextrin polymers was discussed. Results disclosed that the sorption of geosmin by the CDPs followed the Ho and McKay kinetic mechanism with the liquid film diffusion as the rate-determining step. Both β-CDP and γ-CDP exhibit high removal efficiencies of 93.4% and 96%, respectively, within 240 minutes at 25°C and pH 7, whilst α-CDP was not effective, removing only 40% geosmin, at an initial concentration of 5 μg·L—1and 5 g·L—1of CDP dose. The cyclodextrin polymers can adapt to a wide range of pH from 3.0 to 11.0 for geosmin adsorption with pH 7.0 as optimum. Results indicate that these sorbents demonstrate significant potential in reducing the concentration of geosmin in water that presents taint problems in both drinking water and fish.展开更多
Problems due to the taste and odor in drinking water are common in treatment facilities around the world. Taste and odor are perceived by the public as the primary indicators of the safely and acceptability of drinkin...Problems due to the taste and odor in drinking water are common in treatment facilities around the world. Taste and odor are perceived by the public as the primary indicators of the safely and acceptability of drinking water and are mainly caused by the presence of two semi-volatile compounds - 2-methyl isobomeol （MIB） and geosmin. A review of these two taste and odor causing compounds in drinking water is presented. The sources for the formation of these compounds in water are discussed alongwith the health and regulatory implications. The recent developments in the analysis of MIB/geosmin in water which have allowed for rapid measurements in the nanogram per liter concentrations are also discussed. This review focuses on the relevant treatment alternatives, that are described in detail with emphasis on their respective advantages and problems associated with their implementation in a full- scale facility. Conventional treatment processes in water treatment plants, such as coagulation, sedimentation and chlorination have been found to be ineffective for removal of M1B/geosmin. Studies have shown powdered activated carbon, ozonation and biofiltration to be effective in treatment of these two compounds. Although some of these technologies are more effective and show more promise than the others, much work remains to be done to optimize these technologies so that they can be retrofitted or installed with minimal impact on the overall operation and effectiveness of the treatment system.展开更多
Three strains of Gram-negative bacteria capable of removing geosmin from drinking water were isolated from biologically active carbon and identified to be Chryseobacterium sp., Sinorhizobium sp. and Stenotrophomonas s...Three strains of Gram-negative bacteria capable of removing geosmin from drinking water were isolated from biologically active carbon and identified to be Chryseobacterium sp., Sinorhizobium sp. and Stenotrophomonas sp. based on physio-biochemistry analysis and 16S rRNA gene sequence analysis. Removal efficiencies of 2 mg/L geosmin in mineral salts medium were 84.0%, 80.2% and 74.4% for Chryxeobacterium sp., Sinorhizobium sp. and Stenotrophomonas sp., respectively, while removal efficiencies of 560 ng/L geosmin in filter influent were 84.8%, 82.3% and 82.5%, respectively. The biodegradation of geosmin was determined to be a pseudo first-order reaction, with rate constants at 2 mg/L and 560 ng/L being 0.097 and 0.086 day-1, 0.089 and 0.084 day-1, 0.074 and 0.098 day-1 for the above mentioned degraders, respectively. The biomass of culture in the presence of geosmin was much higher than that in the absence of geosmin.展开更多
Two sample preparation methods were introduced and compared in this paper to establish a simple,quick and exact analysis of geosmin and 2-methylisoborneol.LC-18 column was employed in solid phase extraction(SPE),1.0 m...Two sample preparation methods were introduced and compared in this paper to establish a simple,quick and exact analysis of geosmin and 2-methylisoborneol.LC-18 column was employed in solid phase extraction(SPE),1.0 mL of hexane was adopted in liquid-liquid extraction(LLE),and the extracts were analyzed by gas chromatograph mass spectrum(GCMS)in selected ion mode.Mean recoveries of SPE were low for 2-methylisoborneol(2-MIB)and geosmin(GSM)with values below 50%.For LLE,the recoveries were satisfyingly above 50%for 2-MIB and 80%for GSM.Detection limits of the LLE method were as low as 1.0 ng/L for GSM and 5.0 ng/L for 2-MIB.A year-long investigation on odor chemicals of drinking water in Shanghai demonstrated that in the summer,there was a serious odor problem induced by a high concentration of 2-MIB.The highest concentration of 152.82 ng/L appeared in July in raw water,while GSM flocculation was minimal with concentrations below odor threshold.展开更多
文摘Geosmin is one of the major causative compounds of earthy-musty odor and taste (off-flavor) in drinking water (lakes) and in farmed fish. In this study, the sorption of cyclodextrin polymers (CDPs) towards geosmin in aqueous solution was investigated. Sorption kinetics, the effect of solution pH and contact time on the sorption capability of α-, β- and γ-cyclodextrin polymers was discussed. Results disclosed that the sorption of geosmin by the CDPs followed the Ho and McKay kinetic mechanism with the liquid film diffusion as the rate-determining step. Both β-CDP and γ-CDP exhibit high removal efficiencies of 93.4% and 96%, respectively, within 240 minutes at 25°C and pH 7, whilst α-CDP was not effective, removing only 40% geosmin, at an initial concentration of 5 μg·L—1and 5 g·L—1of CDP dose. The cyclodextrin polymers can adapt to a wide range of pH from 3.0 to 11.0 for geosmin adsorption with pH 7.0 as optimum. Results indicate that these sorbents demonstrate significant potential in reducing the concentration of geosmin in water that presents taint problems in both drinking water and fish.
基金supported by the National Natural Science Foundation of China(U0932601,81060263)the Foundation of Key Laboratory of Medicinal Chemistry for Natural Resource,Ministry of Education(2009102202)
文摘Problems due to the taste and odor in drinking water are common in treatment facilities around the world. Taste and odor are perceived by the public as the primary indicators of the safely and acceptability of drinking water and are mainly caused by the presence of two semi-volatile compounds - 2-methyl isobomeol （MIB） and geosmin. A review of these two taste and odor causing compounds in drinking water is presented. The sources for the formation of these compounds in water are discussed alongwith the health and regulatory implications. The recent developments in the analysis of MIB/geosmin in water which have allowed for rapid measurements in the nanogram per liter concentrations are also discussed. This review focuses on the relevant treatment alternatives, that are described in detail with emphasis on their respective advantages and problems associated with their implementation in a full- scale facility. Conventional treatment processes in water treatment plants, such as coagulation, sedimentation and chlorination have been found to be ineffective for removal of M1B/geosmin. Studies have shown powdered activated carbon, ozonation and biofiltration to be effective in treatment of these two compounds. Although some of these technologies are more effective and show more promise than the others, much work remains to be done to optimize these technologies so that they can be retrofitted or installed with minimal impact on the overall operation and effectiveness of the treatment system.
基金supported by the National Science and Technology Major Projects Special for Water Pollution Control and Management (No. 2009ZX07424-003)
文摘Three strains of Gram-negative bacteria capable of removing geosmin from drinking water were isolated from biologically active carbon and identified to be Chryseobacterium sp., Sinorhizobium sp. and Stenotrophomonas sp. based on physio-biochemistry analysis and 16S rRNA gene sequence analysis. Removal efficiencies of 2 mg/L geosmin in mineral salts medium were 84.0%, 80.2% and 74.4% for Chryxeobacterium sp., Sinorhizobium sp. and Stenotrophomonas sp., respectively, while removal efficiencies of 560 ng/L geosmin in filter influent were 84.8%, 82.3% and 82.5%, respectively. The biodegradation of geosmin was determined to be a pseudo first-order reaction, with rate constants at 2 mg/L and 560 ng/L being 0.097 and 0.086 day-1, 0.089 and 0.084 day-1, 0.074 and 0.098 day-1 for the above mentioned degraders, respectively. The biomass of culture in the presence of geosmin was much higher than that in the absence of geosmin.
基金This study was supported by the National High-Tech Research and Development(863)Program of China(Grant No.2002AA601130)the Key Technologies Research and Development Program(No.2003BA808A17)of China.
文摘Two sample preparation methods were introduced and compared in this paper to establish a simple,quick and exact analysis of geosmin and 2-methylisoborneol.LC-18 column was employed in solid phase extraction(SPE),1.0 mL of hexane was adopted in liquid-liquid extraction(LLE),and the extracts were analyzed by gas chromatograph mass spectrum(GCMS)in selected ion mode.Mean recoveries of SPE were low for 2-methylisoborneol(2-MIB)and geosmin(GSM)with values below 50%.For LLE,the recoveries were satisfyingly above 50%for 2-MIB and 80%for GSM.Detection limits of the LLE method were as low as 1.0 ng/L for GSM and 5.0 ng/L for 2-MIB.A year-long investigation on odor chemicals of drinking water in Shanghai demonstrated that in the summer,there was a serious odor problem induced by a high concentration of 2-MIB.The highest concentration of 152.82 ng/L appeared in July in raw water,while GSM flocculation was minimal with concentrations below odor threshold.
