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
Adsorption is one of the several techniques that has been successfully used for dyes removal.Since most industrial colored effluents contain several components including dyes,having a strong knowledge about the scope ...Adsorption is one of the several techniques that has been successfully used for dyes removal.Since most industrial colored effluents contain several components including dyes,having a strong knowledge about the scope of competitive adsorption process is a powerful key to design an appropriate system.This is mainly because of the complexity brought about by the increasing number of parameters needed for process description which complicates not only the process modeling but also the experimental data collection.A multicomponent adsorption model should be based on fundamental soundness,speed,and simplicity of calculation.For such systems,competition will change the adsorbent-adsorbate attractions.Thus,there is major concern to develop an accurate and reliable method to predict dye adsorption behavior in multi-component systems.This article covers topics such as the theory of dyes adsorption in multi-component systems along with applicable models according to the consistent theories presented by researchers.展开更多
This study investigated the removal of hydrophobic trichloroethylene（TCE） in the presence of methanol（co-metabolite） in a biotrickling filter,which was seeded with fungi at pH 4.Starvation was chosen as the biomas...This study investigated the removal of hydrophobic trichloroethylene（TCE） in the presence of methanol（co-metabolite） in a biotrickling filter,which was seeded with fungi at pH 4.Starvation was chosen as the biomass control strategy.Two systems,Biofilter I（methanol：TCE 70：30） and Biofilter II（methanol：TCE 80：20） were run in parallel,each with varying composition ratios.The TCE loading rates for both biofilters ranged from 3.22 to 12.88 g/m^3/hr.Depending on the ratio,methanol concentrations varied from 4.08 to 27.95 g/m^3/hr.The performance of the systems was evaluated and compared by calculating removal kinetics,carbon mass balance,efficiencies and elimination capacities.Methanol was observed to enhance TCE removal during the initial loading rate.However,methanol later inhibited TCE degradation above 6.44 g TCE/m^3/hr（Biofilter I） and 3.22 g TCE/m^3/hr（Biofilter II）.Conversely,TCE did not impede methanol removal because over 95% methanol elimination was consistently achieved.Overall,Biofilter I was able to outperform Biofilter II due to its greater resistance towards methanol competition.展开更多
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.
文摘Adsorption is one of the several techniques that has been successfully used for dyes removal.Since most industrial colored effluents contain several components including dyes,having a strong knowledge about the scope of competitive adsorption process is a powerful key to design an appropriate system.This is mainly because of the complexity brought about by the increasing number of parameters needed for process description which complicates not only the process modeling but also the experimental data collection.A multicomponent adsorption model should be based on fundamental soundness,speed,and simplicity of calculation.For such systems,competition will change the adsorbent-adsorbate attractions.Thus,there is major concern to develop an accurate and reliable method to predict dye adsorption behavior in multi-component systems.This article covers topics such as the theory of dyes adsorption in multi-component systems along with applicable models according to the consistent theories presented by researchers.
文摘This study investigated the removal of hydrophobic trichloroethylene（TCE） in the presence of methanol（co-metabolite） in a biotrickling filter,which was seeded with fungi at pH 4.Starvation was chosen as the biomass control strategy.Two systems,Biofilter I（methanol：TCE 70：30） and Biofilter II（methanol：TCE 80：20） were run in parallel,each with varying composition ratios.The TCE loading rates for both biofilters ranged from 3.22 to 12.88 g/m^3/hr.Depending on the ratio,methanol concentrations varied from 4.08 to 27.95 g/m^3/hr.The performance of the systems was evaluated and compared by calculating removal kinetics,carbon mass balance,efficiencies and elimination capacities.Methanol was observed to enhance TCE removal during the initial loading rate.However,methanol later inhibited TCE degradation above 6.44 g TCE/m^3/hr（Biofilter I） and 3.22 g TCE/m^3/hr（Biofilter II）.Conversely,TCE did not impede methanol removal because over 95% methanol elimination was consistently achieved.Overall,Biofilter I was able to outperform Biofilter II due to its greater resistance towards methanol competition.
