A new recovery technology is developed to recycle N,N-dimethyl formamide （DMF） in waste gas from wet type polyurethane synthetic leather industry. Given that the concentration of DMF in waste gas was as low as 325.6...A new recovery technology is developed to recycle N,N-dimethyl formamide （DMF） in waste gas from wet type polyurethane synthetic leather industry. Given that the concentration of DMF in waste gas was as low as 325.6- 688.3 mg·m^-3, it was necessary to make sure two phases contact adequately and strengthen the mass transfer by increasing contact area and enhancing the turbulence. Therefore, two-stage countercurrent absorption and two-stage fog removing system were introduced into the technology. The top section of the absorption column was filled with structured wire-ripple stainless steel packing BX500, while the lower section with sting-ripple packing CB250Y. Total height of packing material was 6 m. In addition, there were both two-stage fog removing layer and high efficiency liquid distributor at the column top. All the operating parameters, including temperature, pressure, flow rate and liquid position, could be controlled by computers without manual operation, making sure the outlet gas achieved the national emission standard that the DMF concentration should be below 40 mg·m^-3. The whole equipment could recover 237.6 t of DMF each year, with the profit up to CNY 521×10^3.展开更多
Traditional chrome tanning technology is still widely used today. In this technology, chrome shaving as well as chrome contained effluent in tanning and retanning processes is a big issue in the industry. Wet white ta...Traditional chrome tanning technology is still widely used today. In this technology, chrome shaving as well as chrome contained effluent in tanning and retanning processes is a big issue in the industry. Wet white tanning technology has been gaining in importance in recent years, but in general, the comprehensive performance of chrome-free tanned leather is not comparable with that of chrome tanned leather. In the present work, chrome-free tanning and chrome tanning are combined in a reversed procedure, which produces leather with chrome tanned leather quality without chrome tanned leather waste problems. In this procedure, a special amphoteric organic compound, no pickle, no salt chrome-free tanning agent TWT was used to tan delimed hides （no pickle） making wet white with shrinking temperature at 80-85 ~C. Then, new method called reversed tanning further process the wet white into chrome-tanned crust. In this reversed method, retanning, fatliquoring and coloring processes were carried out before chrome tanning. This technology eliminates chrome waste issue in tanning, shaving, post tanning processes. The chrome contained effluent is only concentrated in the last chrome tanning process. The leather made with this technology has complete conventional chrome-tanned leather quality. In this way, chrome leather quality without chrome waste problems was achieved. So, it is a new clean tanning technology.展开更多
Leather industry is an important light industry in China.Leather making requires a series of chemical treatment.Degreasing,unhairing and chrome tanning wastewaters are the main portions of tannery wastewater.Reclaimin...Leather industry is an important light industry in China.Leather making requires a series of chemical treatment.Degreasing,unhairing and chrome tanning wastewaters are the main portions of tannery wastewater.Reclaiming and reusing these wastewaters can eliminate 80% of COD,75% of BOD,95% of chromium and 93% of sulfuret,furthermore reduce environment impact,decrease treatment costs,save chemicals and water.Some application methods of wastewater reclamation and reuse for different operations were reported.The suitable reclamation and reuse technologies can enable leather making processes more rational,and realize the recovery and recycle of several chemicals in the tannery.Resourceful utilization of tannery wastewater should mate with renovating production technology,updating equipment,and must be guaranteed sufficiently by environmental protection measures.展开更多
A laboratory experiment was undertaken in Soil Science Division of BRRI （Bangladesh Rice Research Institute） during 2010 to assess the quality of industrial effluents and city waste as a source of irrigation water f...A laboratory experiment was undertaken in Soil Science Division of BRRI （Bangladesh Rice Research Institute） during 2010 to assess the quality of industrial effluents and city waste as a source of irrigation water for agriculture. The treatments of the studies were the effluents of five different industrial sources like polyvinyl, dyeing, pharmaceuticals, beverage, tannery, mixed waste water （contaminated with effluents from many industries）, CWW （city waste water） and underground water as control. The industrial effluents, MWW （mixed waste water）, CWW and control water were tested for electrical conductivity, pH, and soluble ions such as Na^＋, Ca^2＋, Mg^2＋, K^＋, HCO3-, CO3^2-, NH4^＋-N and H2PO4^-. Micronutrients （Fe, Mn, Cu and Zn） and heavy metals （As, Pb, Cd, Cr and Ni） were analyzed from the samples. Beverage industry effluent showed acidic reaction, while the other industrial effluents showed alkaline reaction （pH 7.25-9.07）. Pharmaceutical, dyeing and tannery effluents showed EC of 3.40, 4.30 and 9.49 dS m^-1, respectively, compared to 0.54 dSm^-1 of the control. All the effluents except polyvinyl and beverage effluents and CWW recorded higher carbonate and bicarbonate content than that of control. Industrial effluents and CWW were higher in micronutrient content as compared to control. Dyeing, pharmaceutical and tannery effluents contained 2.51, 3.94 and 4.29 mg L^-1 lead, 0.15, 0.14 and 0.38 mg L^-1 chromium and 0.25, 0.24 and 0.16 mg L^-1 nickel, respectively which might be concemed for health hazard through food chain.展开更多
The present study is conducted in the scenario of the tannery waste hazards in Kasur district of Pakistan where the tannery industry is considered as major cause of groundwater quality deterioration, Area focused in t...The present study is conducted in the scenario of the tannery waste hazards in Kasur district of Pakistan where the tannery industry is considered as major cause of groundwater quality deterioration, Area focused in this research constitutes the surroundings of the effluent carrying drains near tannery units. This study includes soil explorations, groundwater monitoring and wastewater analysis in the research area so as to find out the contamination extent of chromium in subsurface. Initial groundwater monitoring exhibited chromium concentrations as high as 90 mg/L in the tannery area. Even groundwater sampling from monitoring wells installed in the adjacent areas of effluent carrying drains, showed concentrations up to 10.4 mg/L. Wastewater analysis of all the drains in the research area has evidenced potential risk of contaminant seepage into soil and groundwater as level of chromium in wastewater samples has reported to be immensely high and varies from 68 mg/L to 2,152 mg/L. However the 30 soil samples collected from two soil bores did not show any significant results as the maximum values obtained for hexavalent chromium for leaching and retained in soil are 0.02 mg/L and 8.1 mg/kg, respectively. These low concentrations of soil samples suggest that the soil contamination may not be a main environmental issue in the areas adjacent to the effluent carrying drains, The research concludes as possibility of direct interference of the tannery wastewater with groundwater through damaged structures and sewers.展开更多
Due to improper tannery wastewater management in district Kasur Pakistan, groundwater has been reported to be highly contaminated. It was aimed to find out the extent up to which subsurface has contaminated due to chr...Due to improper tannery wastewater management in district Kasur Pakistan, groundwater has been reported to be highly contaminated. It was aimed to find out the extent up to which subsurface has contaminated due to chromium in areas adjacent to the tannery units. Eight （8） soil bores were conducted up to the depth of 30.5 meters and soil samples were tested for total and hexavalent chromium concentrations retained in soil by aqua regia digestion at the every depth of 1.5 meters. Afterwards monitoring wells were installed in these eight （8） bores so as to monitor chromium concentrations in the groundwater on monthly basis. The main source of contamination was considered to be the four （4） drains carrying tanneries effluent therefore samples were collected from these drains so as to observe seasonal variation in chromium concentration.展开更多
The revolution in information and communication technology has brought huge technical benefits and wealth, but has created a major global problem： the generation of vast amounts of electronic waste, or e-waste throug...The revolution in information and communication technology has brought huge technical benefits and wealth, but has created a major global problem： the generation of vast amounts of electronic waste, or e-waste through product obsolesce. The challenge in managing e-waste will be in developing sustainable recycling tech- nologies that are able to address the volume and complexity of this waste using cost effective and ecologically sen-sitive methods. In this study, the capability or microorganism metabolic acids in dissolving the metallic tractions from waste printed circuit boards was examined. Several factors were considered in the examination of the activityof the acids-including secondary reactions, solution pH, temperature and the nature of ligands in solutions （or bioacid constituents）. The leaching tests were cgnducted ex-situ, using synthetic organic acids. Leaching was performed for periods of up to 6 hat 70-90 ℃ and 1000 r-min-1.展开更多
基金the Science and Technology Fund of Zhejiang Province, China (2006C13072)
文摘A new recovery technology is developed to recycle N,N-dimethyl formamide （DMF） in waste gas from wet type polyurethane synthetic leather industry. Given that the concentration of DMF in waste gas was as low as 325.6- 688.3 mg·m^-3, it was necessary to make sure two phases contact adequately and strengthen the mass transfer by increasing contact area and enhancing the turbulence. Therefore, two-stage countercurrent absorption and two-stage fog removing system were introduced into the technology. The top section of the absorption column was filled with structured wire-ripple stainless steel packing BX500, while the lower section with sting-ripple packing CB250Y. Total height of packing material was 6 m. In addition, there were both two-stage fog removing layer and high efficiency liquid distributor at the column top. All the operating parameters, including temperature, pressure, flow rate and liquid position, could be controlled by computers without manual operation, making sure the outlet gas achieved the national emission standard that the DMF concentration should be below 40 mg·m^-3. The whole equipment could recover 237.6 t of DMF each year, with the profit up to CNY 521×10^3.
文摘Traditional chrome tanning technology is still widely used today. In this technology, chrome shaving as well as chrome contained effluent in tanning and retanning processes is a big issue in the industry. Wet white tanning technology has been gaining in importance in recent years, but in general, the comprehensive performance of chrome-free tanned leather is not comparable with that of chrome tanned leather. In the present work, chrome-free tanning and chrome tanning are combined in a reversed procedure, which produces leather with chrome tanned leather quality without chrome tanned leather waste problems. In this procedure, a special amphoteric organic compound, no pickle, no salt chrome-free tanning agent TWT was used to tan delimed hides （no pickle） making wet white with shrinking temperature at 80-85 ~C. Then, new method called reversed tanning further process the wet white into chrome-tanned crust. In this reversed method, retanning, fatliquoring and coloring processes were carried out before chrome tanning. This technology eliminates chrome waste issue in tanning, shaving, post tanning processes. The chrome contained effluent is only concentrated in the last chrome tanning process. The leather made with this technology has complete conventional chrome-tanned leather quality. In this way, chrome leather quality without chrome waste problems was achieved. So, it is a new clean tanning technology.
文摘Leather industry is an important light industry in China.Leather making requires a series of chemical treatment.Degreasing,unhairing and chrome tanning wastewaters are the main portions of tannery wastewater.Reclaiming and reusing these wastewaters can eliminate 80% of COD,75% of BOD,95% of chromium and 93% of sulfuret,furthermore reduce environment impact,decrease treatment costs,save chemicals and water.Some application methods of wastewater reclamation and reuse for different operations were reported.The suitable reclamation and reuse technologies can enable leather making processes more rational,and realize the recovery and recycle of several chemicals in the tannery.Resourceful utilization of tannery wastewater should mate with renovating production technology,updating equipment,and must be guaranteed sufficiently by environmental protection measures.
文摘A laboratory experiment was undertaken in Soil Science Division of BRRI （Bangladesh Rice Research Institute） during 2010 to assess the quality of industrial effluents and city waste as a source of irrigation water for agriculture. The treatments of the studies were the effluents of five different industrial sources like polyvinyl, dyeing, pharmaceuticals, beverage, tannery, mixed waste water （contaminated with effluents from many industries）, CWW （city waste water） and underground water as control. The industrial effluents, MWW （mixed waste water）, CWW and control water were tested for electrical conductivity, pH, and soluble ions such as Na^＋, Ca^2＋, Mg^2＋, K^＋, HCO3-, CO3^2-, NH4^＋-N and H2PO4^-. Micronutrients （Fe, Mn, Cu and Zn） and heavy metals （As, Pb, Cd, Cr and Ni） were analyzed from the samples. Beverage industry effluent showed acidic reaction, while the other industrial effluents showed alkaline reaction （pH 7.25-9.07）. Pharmaceutical, dyeing and tannery effluents showed EC of 3.40, 4.30 and 9.49 dS m^-1, respectively, compared to 0.54 dSm^-1 of the control. All the effluents except polyvinyl and beverage effluents and CWW recorded higher carbonate and bicarbonate content than that of control. Industrial effluents and CWW were higher in micronutrient content as compared to control. Dyeing, pharmaceutical and tannery effluents contained 2.51, 3.94 and 4.29 mg L^-1 lead, 0.15, 0.14 and 0.38 mg L^-1 chromium and 0.25, 0.24 and 0.16 mg L^-1 nickel, respectively which might be concemed for health hazard through food chain.
文摘The present study is conducted in the scenario of the tannery waste hazards in Kasur district of Pakistan where the tannery industry is considered as major cause of groundwater quality deterioration, Area focused in this research constitutes the surroundings of the effluent carrying drains near tannery units. This study includes soil explorations, groundwater monitoring and wastewater analysis in the research area so as to find out the contamination extent of chromium in subsurface. Initial groundwater monitoring exhibited chromium concentrations as high as 90 mg/L in the tannery area. Even groundwater sampling from monitoring wells installed in the adjacent areas of effluent carrying drains, showed concentrations up to 10.4 mg/L. Wastewater analysis of all the drains in the research area has evidenced potential risk of contaminant seepage into soil and groundwater as level of chromium in wastewater samples has reported to be immensely high and varies from 68 mg/L to 2,152 mg/L. However the 30 soil samples collected from two soil bores did not show any significant results as the maximum values obtained for hexavalent chromium for leaching and retained in soil are 0.02 mg/L and 8.1 mg/kg, respectively. These low concentrations of soil samples suggest that the soil contamination may not be a main environmental issue in the areas adjacent to the effluent carrying drains, The research concludes as possibility of direct interference of the tannery wastewater with groundwater through damaged structures and sewers.
文摘Due to improper tannery wastewater management in district Kasur Pakistan, groundwater has been reported to be highly contaminated. It was aimed to find out the extent up to which subsurface has contaminated due to chromium in areas adjacent to the tannery units. Eight （8） soil bores were conducted up to the depth of 30.5 meters and soil samples were tested for total and hexavalent chromium concentrations retained in soil by aqua regia digestion at the every depth of 1.5 meters. Afterwards monitoring wells were installed in these eight （8） bores so as to monitor chromium concentrations in the groundwater on monthly basis. The main source of contamination was considered to be the four （4） drains carrying tanneries effluent therefore samples were collected from these drains so as to observe seasonal variation in chromium concentration.
基金Supported by Australian Research Council's Discovery Projects fundings scheme(DP1096342)
文摘The revolution in information and communication technology has brought huge technical benefits and wealth, but has created a major global problem： the generation of vast amounts of electronic waste, or e-waste through product obsolesce. The challenge in managing e-waste will be in developing sustainable recycling tech- nologies that are able to address the volume and complexity of this waste using cost effective and ecologically sen-sitive methods. In this study, the capability or microorganism metabolic acids in dissolving the metallic tractions from waste printed circuit boards was examined. Several factors were considered in the examination of the activityof the acids-including secondary reactions, solution pH, temperature and the nature of ligands in solutions （or bioacid constituents）. The leaching tests were cgnducted ex-situ, using synthetic organic acids. Leaching was performed for periods of up to 6 hat 70-90 ℃ and 1000 r-min-1.
