In Mexico, hazardous and non-hazardous urban solid wastes are commonly disposed of in dumps. Inappropriate waste disposal makes solid waste disposal sites potential sources of pollution and health risks. The objective...In Mexico, hazardous and non-hazardous urban solid wastes are commonly disposed of in dumps. Inappropriate waste disposal makes solid waste disposal sites potential sources of pollution and health risks. The objective of the present study was to evaluate the impact of leachate from a dump on surface water systems. Physical, chemical, and bacteriological characteristics and the volume of leachate were measured. The site of study is located in Zinaprcuaro, Michoac^m, Mexico, and was chosen due to the water supplies were in line with the dump, thus conforming a system to test for movement of toxins. Leachate and water from three ponds located at different distances to the dump were sampled during three months of a year to measure physicochemical and bacteriological parameters, according to the standard methods of the American Public Health Association; the concentration of heavy metals was measured by atomic absorption spectrometry. Most characteristics exceed the maximum permissible limits established for the Mexican legislation regarding wastewater discharges and drinking water. Likewise, analysis of variance showed statistically significant differences between concentrations of pollutants in relation to the distance from the dump of sampled sites and with season of sampling, thus confirming the contamination of water by dump leachate.展开更多
Mismanagement of the composting process can result in emissions of CH4,N2O,and NH3,which have caused severe environmental problems.This study was aimed at determining whether CH4,N2O,and NH3 emissions from composting ...Mismanagement of the composting process can result in emissions of CH4,N2O,and NH3,which have caused severe environmental problems.This study was aimed at determining whether CH4,N2O,and NH3 emissions from composting are affected by bulking agents during rapid composting of pig manure from the Chinese Ganqinfen system.Three bulking agents,corn stalks,spent mushroom compost,and sawdust,were used in composting with pig manure in 60 L reactors with forced aeration for more than a month.Gas emissions were measured continuously,and detailed gas emission patterns were obtained.Concentrations of NH3 and N2O from the composting pig manure mixed with corn stalks or sawdust were higher than those from the spent mushroom compost treatment,especially the sawdust treatment,which had the highest total nitrogen loss among the three runs.Most of the nitrogen was lost in the form of NH3,which accounts for 11.16% to 35.69% of the initial nitrogen.One-way analysis of variance for NH3emission showed no significant differences between the corn stalk and sawdust treatments,but a significant difference was noted between the spent mushroom compost and sawdust treatments.The introduction of sawdust reduced CH4emission more than the corn stalks and spent mushroom compost.However,there were no significant differences among the three runs for total carbon loss.All treatments were matured after 30 d.展开更多
文摘In Mexico, hazardous and non-hazardous urban solid wastes are commonly disposed of in dumps. Inappropriate waste disposal makes solid waste disposal sites potential sources of pollution and health risks. The objective of the present study was to evaluate the impact of leachate from a dump on surface water systems. Physical, chemical, and bacteriological characteristics and the volume of leachate were measured. The site of study is located in Zinaprcuaro, Michoac^m, Mexico, and was chosen due to the water supplies were in line with the dump, thus conforming a system to test for movement of toxins. Leachate and water from three ponds located at different distances to the dump were sampled during three months of a year to measure physicochemical and bacteriological parameters, according to the standard methods of the American Public Health Association; the concentration of heavy metals was measured by atomic absorption spectrometry. Most characteristics exceed the maximum permissible limits established for the Mexican legislation regarding wastewater discharges and drinking water. Likewise, analysis of variance showed statistically significant differences between concentrations of pollutants in relation to the distance from the dump of sampled sites and with season of sampling, thus confirming the contamination of water by dump leachate.
基金supported by the National Natural Science Foundation of China(Nos.41275161 and 41075110)the National Science&Technology Pillar Program(Nos.2012BAD14B01 and 2012BAD14B03)+1 种基金the Sino-German Cooperation Project of Recycling of Organic Residues from Agricultural and Municipal Residues in China(No.BMBF FKZ 0330847)the Chinese Universities Scientific Fund
文摘Mismanagement of the composting process can result in emissions of CH4,N2O,and NH3,which have caused severe environmental problems.This study was aimed at determining whether CH4,N2O,and NH3 emissions from composting are affected by bulking agents during rapid composting of pig manure from the Chinese Ganqinfen system.Three bulking agents,corn stalks,spent mushroom compost,and sawdust,were used in composting with pig manure in 60 L reactors with forced aeration for more than a month.Gas emissions were measured continuously,and detailed gas emission patterns were obtained.Concentrations of NH3 and N2O from the composting pig manure mixed with corn stalks or sawdust were higher than those from the spent mushroom compost treatment,especially the sawdust treatment,which had the highest total nitrogen loss among the three runs.Most of the nitrogen was lost in the form of NH3,which accounts for 11.16% to 35.69% of the initial nitrogen.One-way analysis of variance for NH3emission showed no significant differences between the corn stalk and sawdust treatments,but a significant difference was noted between the spent mushroom compost and sawdust treatments.The introduction of sawdust reduced CH4emission more than the corn stalks and spent mushroom compost.However,there were no significant differences among the three runs for total carbon loss.All treatments were matured after 30 d.
