Solid Waste Generation and Composition in Mexico： A Comparison between Rural and Urban Communities

This paper reports a generation and composition analysis of household solid waste in Mexico, using as a reference the characterization study performed in two communities, one urban and one rural. Data obtained are fundamental parameters for the planning of urban solid waste management systems in Mexico, complying this way with the established policy in the National Program for Waste Management and Prevention 2009-2012. The study was carried out during five days and two main parameters were assessed： （1） the daily generation rate per person and （2） the waste composition. The per capita waste generation was 0.958 kg for the urban community and 0.631 kg for the rural. The results showed that the mean composition of waste from both locations was statistically similar （a = 0.05）. In both locations the most important contribution was the fraction of food waste. In both locations more than 60% of the waste is potentially recyclable. The results of this study will be used by the municipal waste authorities in order to establish an integrated waste management plan.

A Survey of the Gasification of Residual Household Waste

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.

Characterization of municipal solid waste based on seasonal variations,source and socio-economic aspects

Municipal solid waste(MSW)generation and characterization are the basic inputs for waste handling and treatment systems design.In present research,we performed waste characterization investigations in Visakhapatnam(India),using a waste characterization methodology by integrating two standard sampling and characterization approaches.The characterization methodology was designed by combining seasonal variations,source,and socio-economic stratifications.Source-based sampling was performed at household(s),dumpster(s),transfer station,and landfill.Socio-economic-based sampling was performed based on the zone classification of the city.Three sampling campaigns were conducted to identify the waste composition based on seasonal variations.Studies aimed to perform stratified characterization of waste and assess chemical characteristics of the mixed waste fractions to evaluate waste-to-energy potential.Results indicate that the amount of MSW generated in the city is 1250±100 tons/day,with a generation rate of 0.65 kg/capita/day.Based on source stratification,organic matter(45.5%±6.5%)is a major component followed by inert waste.The paper,plastic,and textile components amount to 25%of overall waste.From seasonal studies,organic matter was higher in pre-monsoon(42%)compared to winter(39%).The moisture content of MSW varied between 30%and 35%and volatile solids between 39%and 43%.The calorific value was determined to be between 5680-7110 kJ/kg.Outlined the limitations and potential errors associated with sampling and waste characterization.Biochemical and thermal conversion treatment alternatives for processing,treatment,and handling were discussed.The findings of this research would assist regulatory bodies and city councils to formulate policy directives on waste sampling,characterization,segregation,education,and awareness campaigns.

Effect of Preparation Temperature on the Aging Properties of Waste Polyethylene Modified Asphalt

In this study, waste polyethylene(WPE) was used as a modifier for base asphalt. In our previous studies,we have examined a variety of polymer modifiers for asphalt. By contrast, little research has focused on the preparation process, such as preparation time, preparation temperature and shear rate. The effect of preparation temperature on aging properties of WPE-modified asphalt was investigated in this work. The experimental materials were characterized by infrared spectroscopy(IR), thermo-gravimetric analysis(TG), and differential scanning calorimetry(DSC). The physical properties were determined by conducting asphalt penetration, softening point and ductility tests. The results show that increasing the preparation temperature results in an increased softening point of WPE-modified asphalt while decreased penetration and ductility. In addition, this variation was accentuated by aging the experimental materials. The modification process of WPE is a physical process. During the asphalt modification process, the WPE aged as the preparation temperature increased. The results revealed that 190 C is the most suitable preparation temperature, and the post aged asphalt demonstrated improved high temperature stability.