Volatile organic compounds （VOCs） are widely used in various industrial processes and generate water pollutions. VOCs removal from raw water is an important task for waterworks to guarantee drinking water security. ...Volatile organic compounds （VOCs） are widely used in various industrial processes and generate water pollutions. VOCs removal from raw water is an important task for waterworks to guarantee drinking water security. The removal of VOCs such as chlorobenzene （CB） and ethylbenzene （EB） from raw water by air stripping was investigated under various conditions, inciuding the variation of temperature （5-30~C）, pH （3.5-10.5）, and air/water ratio （10-60）. The air stripping removal efficiency of VOCs decreased with VOCs concentration declining in water. And Henry＇s law constant was demonstrated as an indicator of the estimation of VOCs removal efficiency for air stripping. The effects of temperature and the ratio of air and water were found to play a great role in VOCs removal, but the effect of pH seemed to be negligible. This study demonstrates that air stripping provides a promising opportunity in removing VOCs in drinking water treatment, especially for the relatively high concentration of VOCs.展开更多
Based on the effects of skim components on ammonium removal as well as the current processing technology, a new process-intensified technology of removing ammonia from skim by air stripping on rotating packed bed was ...Based on the effects of skim components on ammonium removal as well as the current processing technology, a new process-intensified technology of removing ammonia from skim by air stripping on rotating packed bed was proposed. The experiments were conducted on a wave-thread packed Rotating Packed Bed(RPB) under atmospheric pressure, suggesting that, in terms of order of importance, the ammonium concentration of feed-stock(x_w), the average ultra-gravity factor(β), feed-stock flux(L), and gas flux(G) had significant impact on ammonium removal rate(η) and the ammonium concentration of products(x_D). In the experiment, mass-transfer coefficient in gas phase(k_ya_e) increases with the increase of β, G/L, and L. The ammonium concentration of products decreases with the increase of β, G/L and the increase of L. The ammonium concentration of products would be as low as ~0.10% and the ammonia removal rate would be 63.21% when skim temperature was 25 °C, x_w0.28%, β 133.2, and G/L 15.0 m^3·L^(-1). Experiment results indicated that the proposed technology for removing ammonium from skim on a rotating packed bed would be a new process-intensified technique compared with traditional aeration process and centrifugal atomization method.展开更多
Air-stripping method was used to remove ammonia from the wastewater collected from natural gas fertilizer factory. Different materials were used as packing materials for the air stripping system. The effect of pH over...Air-stripping method was used to remove ammonia from the wastewater collected from natural gas fertilizer factory. Different materials were used as packing materials for the air stripping system. The effect of pH over 10.5, air-water flow ratio, nature of packing materials, height of materials and initial influent concentration of ammonia on air stripping unit were investigated. An attempt has been made to find out the stripping con-stant. Stripping constant was found to be .001, 0014, .001 and .0009 for coal, plastic ring, stone chips and wood chips, respectively. Best result was found for plastic ring for its higher surface area. Wood chips did not give good result, because the chips amalgamate with each other and hence reduces the surface area.展开更多
Based on the traditional method of high concentration ammonia removal from wastewater,a mixture mainly consisting of ethyl lactate and acetic acid is used as an aid for ammonia removal by air stripping.The effect of d...Based on the traditional method of high concentration ammonia removal from wastewater,a mixture mainly consisting of ethyl lactate and acetic acid is used as an aid for ammonia removal by air stripping.The effect of dosage,the depth of air nozzle in water and other conditions for ammonia removal were investigated.The results show that under the conditions that denitrification reagent is in the dosage of 30 mg/L,pH value is 9-11,blowing depth is 400 mm,stripping time is greater than 2.5 h,and the temperature is normal(25°C),the concentration of ammonia nitrogen in wastewater can be reduced from 21006.0 mg/L to 10.6 mg/L. The ammonia nitrogen removal rate is up to 99.95%.At the temperature of 45°C,the concentration of ammonia nitrogen in wastewater can be decreased from 21006 mg/L to 0.2 mg/L.The ammonia nitrogen removal rate is up to 99.999%.When the wastewater ammonia concentration is between 800-30000 mg/L,the ammonia is air stripped under the above mentioned conditions,the residual concentration can be below 15 mg/L.The stripped ammonia can be absorbed without secondary pollution.展开更多
基金National High Technology Research and Development Program of China(863 program)(No.2008AA06A414)Major Science and Technology Proyran for Water Pollution Control and Treatment,China(No.2008ZX07421-003)
文摘Volatile organic compounds （VOCs） are widely used in various industrial processes and generate water pollutions. VOCs removal from raw water is an important task for waterworks to guarantee drinking water security. The removal of VOCs such as chlorobenzene （CB） and ethylbenzene （EB） from raw water by air stripping was investigated under various conditions, inciuding the variation of temperature （5-30~C）, pH （3.5-10.5）, and air/water ratio （10-60）. The air stripping removal efficiency of VOCs decreased with VOCs concentration declining in water. And Henry＇s law constant was demonstrated as an indicator of the estimation of VOCs removal efficiency for air stripping. The effects of temperature and the ratio of air and water were found to play a great role in VOCs removal, but the effect of pH seemed to be negligible. This study demonstrates that air stripping provides a promising opportunity in removing VOCs in drinking water treatment, especially for the relatively high concentration of VOCs.
基金Supported by the Opening Project Fund of Key Laboratory of Danzhou Investigation&Experiment Station of Tropical Crops,Ministry of Agriculture(RRI-KLOF201701)
文摘Based on the effects of skim components on ammonium removal as well as the current processing technology, a new process-intensified technology of removing ammonia from skim by air stripping on rotating packed bed was proposed. The experiments were conducted on a wave-thread packed Rotating Packed Bed(RPB) under atmospheric pressure, suggesting that, in terms of order of importance, the ammonium concentration of feed-stock(x_w), the average ultra-gravity factor(β), feed-stock flux(L), and gas flux(G) had significant impact on ammonium removal rate(η) and the ammonium concentration of products(x_D). In the experiment, mass-transfer coefficient in gas phase(k_ya_e) increases with the increase of β, G/L, and L. The ammonium concentration of products decreases with the increase of β, G/L and the increase of L. The ammonium concentration of products would be as low as ~0.10% and the ammonia removal rate would be 63.21% when skim temperature was 25 °C, x_w0.28%, β 133.2, and G/L 15.0 m^3·L^(-1). Experiment results indicated that the proposed technology for removing ammonium from skim on a rotating packed bed would be a new process-intensified technique compared with traditional aeration process and centrifugal atomization method.
文摘Air-stripping method was used to remove ammonia from the wastewater collected from natural gas fertilizer factory. Different materials were used as packing materials for the air stripping system. The effect of pH over 10.5, air-water flow ratio, nature of packing materials, height of materials and initial influent concentration of ammonia on air stripping unit were investigated. An attempt has been made to find out the stripping con-stant. Stripping constant was found to be .001, 0014, .001 and .0009 for coal, plastic ring, stone chips and wood chips, respectively. Best result was found for plastic ring for its higher surface area. Wood chips did not give good result, because the chips amalgamate with each other and hence reduces the surface area.
基金supported by Water Pollution Control and Management of Chinese Special Key Science and Technology Project(2008ZX07101007-01)
文摘Based on the traditional method of high concentration ammonia removal from wastewater,a mixture mainly consisting of ethyl lactate and acetic acid is used as an aid for ammonia removal by air stripping.The effect of dosage,the depth of air nozzle in water and other conditions for ammonia removal were investigated.The results show that under the conditions that denitrification reagent is in the dosage of 30 mg/L,pH value is 9-11,blowing depth is 400 mm,stripping time is greater than 2.5 h,and the temperature is normal(25°C),the concentration of ammonia nitrogen in wastewater can be reduced from 21006.0 mg/L to 10.6 mg/L. The ammonia nitrogen removal rate is up to 99.95%.At the temperature of 45°C,the concentration of ammonia nitrogen in wastewater can be decreased from 21006 mg/L to 0.2 mg/L.The ammonia nitrogen removal rate is up to 99.999%.When the wastewater ammonia concentration is between 800-30000 mg/L,the ammonia is air stripped under the above mentioned conditions,the residual concentration can be below 15 mg/L.The stripped ammonia can be absorbed without secondary pollution.
