Adverse health and environmental effects of household dust are derived from their chemical composition and properties. In this study, household, stairs and entryway dust (<20 μm) samples from homes located in urba...Adverse health and environmental effects of household dust are derived from their chemical composition and properties. In this study, household, stairs and entryway dust (<20 μm) samples from homes located in urban, residential and residential near to industrial area in Greater Cairo during summer 2013 were collected to study their chemical composition, characterization and factors affecting them. Results indicate that the levels of measured anions and cations were higher in the household compared to stairs and entryway dust. The highest concentration of ?, , Cl-?,?, Na+, K+, Ca2+ and Mg2+ in the household and entryway dust was found in urban area. was abundant in household, entryway and stairs dust followed by Cl- and . Its average concentrations were 21.38, 14.57 and 15.83 mg/g, respectively. The household/entryway (I/O) concentration ratios of measured ion components indicate that these species might derive from indoor sources, although outdoor sources could be present as well. pH values of household, stairs and entryway dust ranged from 6.43 to 8.53, indicating that these dusts brought a large amount of crustal species, and might alleviate the tendency of acidification. The relationships between the concentrations of acidic components ( and ) and basic components (, Ca2+ and Mg2+) in household, stairs and entryway dust confirm that the acidity of dust is neutralized. Ca2+ and in household and stairs dust and Ca2+ and Mg2+ in entryway dust are the most dominant neutralization substances.展开更多
Solid waste is a promising renewable fuel that can substitute conventional fuel. According to the researchers, thermoconversion of solid waste such as municipal solid waste or residual household waste (RHW) is benefic...Solid waste is a promising renewable fuel that can substitute conventional fuel. According to the researchers, thermoconversion of solid waste such as municipal solid waste or residual household waste (RHW) is beneficial to society. However, due to its heterogeneity, the gasification of RHW is more complex. This review article discusses the steps that RHW must undergo before its thermoconversion and the state of the art of solid waste gasification. First, characterisation methods of RHW are surveyed. Second, the properties of RHW, the production lines of refuse derived fuel (RDF) from RHW, the influence of RDF composition and operating parameters such as equivalence ratio and temperature are reviewed. Moreover, RDF gasification products, scientific barriers and proposed solutions are evaluated. In conclusion, concerning emissions, costs and technical aspects related to each thermochemical process, it can be said that gasification is a promising technique for the recovery of RHW. However, studies on cogasification of waste and biomass on a pilot-industrial scale are still scarce and synergistic effects of this cogasification need to be clarified.展开更多
文摘Adverse health and environmental effects of household dust are derived from their chemical composition and properties. In this study, household, stairs and entryway dust (<20 μm) samples from homes located in urban, residential and residential near to industrial area in Greater Cairo during summer 2013 were collected to study their chemical composition, characterization and factors affecting them. Results indicate that the levels of measured anions and cations were higher in the household compared to stairs and entryway dust. The highest concentration of ?, , Cl-?,?, Na+, K+, Ca2+ and Mg2+ in the household and entryway dust was found in urban area. was abundant in household, entryway and stairs dust followed by Cl- and . Its average concentrations were 21.38, 14.57 and 15.83 mg/g, respectively. The household/entryway (I/O) concentration ratios of measured ion components indicate that these species might derive from indoor sources, although outdoor sources could be present as well. pH values of household, stairs and entryway dust ranged from 6.43 to 8.53, indicating that these dusts brought a large amount of crustal species, and might alleviate the tendency of acidification. The relationships between the concentrations of acidic components ( and ) and basic components (, Ca2+ and Mg2+) in household, stairs and entryway dust confirm that the acidity of dust is neutralized. Ca2+ and in household and stairs dust and Ca2+ and Mg2+ in entryway dust are the most dominant neutralization substances.
文摘Solid waste is a promising renewable fuel that can substitute conventional fuel. According to the researchers, thermoconversion of solid waste such as municipal solid waste or residual household waste (RHW) is beneficial to society. However, due to its heterogeneity, the gasification of RHW is more complex. This review article discusses the steps that RHW must undergo before its thermoconversion and the state of the art of solid waste gasification. First, characterisation methods of RHW are surveyed. Second, the properties of RHW, the production lines of refuse derived fuel (RDF) from RHW, the influence of RDF composition and operating parameters such as equivalence ratio and temperature are reviewed. Moreover, RDF gasification products, scientific barriers and proposed solutions are evaluated. In conclusion, concerning emissions, costs and technical aspects related to each thermochemical process, it can be said that gasification is a promising technique for the recovery of RHW. However, studies on cogasification of waste and biomass on a pilot-industrial scale are still scarce and synergistic effects of this cogasification need to be clarified.
