Application of analytic hierarchy process in a waste treatment technology assessment in Mexico.

The high per capita generation of solid waste and the environmental problems in major rural communities of Ensenada, Baja California, have prompted authorities to seek alternatives for waste treatment. In the absence of a selection methodology, three technologies of waste treatment with energy recovery (an anaerobic digester, a downdraft gasifier, and a plasma gasifier) were evaluated, taking the broader social, political, economic, and environmental issues into considerations. Using the scientific literature as a baseline, interviews with experts, decision makers and the community, and waste stream studies were used to construct a hierarchy that was evaluated by the analytic hierarchy process. In terms of the criteria, judgments, and assumptions made in the model, the anaerobic digester was found to have the highest rating and should consequently be selected as the waste treatment technology for this area. The study results showed low sensitivity, so alternative scenarios were not considered. The methodology developed in this study may be useful for other governments who wish to assess technologies to select waste treatment.

Household hazardous wastes as a potential source of pollution: a generation study.

Certain domestic wastes exhibit characteristics that render them dangerous, such as explosiveness, flammability, spontaneous combustion, reactivity, toxicity and corrosiveness. The lack of information about their generation and composition hinders the creation of special programs for their collection and treatment, making these wastes a potential threat to human health and the environment. We attempted to quantify the levels of hazardous household waste (HHW) generated in Mexicali, Mexico. The analysis considered three socioeconomic strata and eight categories. The sampling was undertaken on a house-by-house basis, and hypothesis testing was based on differences between two proportions for each of the eight categories. In this study, HHW comprised 3.49% of the total generated waste, which exceeded that reported in previous studies in Mexico. The greatest quantity of HHW was generated by the middle stratum; in the upper stratum, most packages were discarded with their contents remaining. Cleaning products represent 45.86% of the HHW generated. Statistical differences were not observed for only two categories among the three social strata. The scarcity of studies on HHW generation limits direct comparisons. Any decrease in waste generation within the middle social stratum will have a large effect on the total amount of waste generated, and decrease their impact on environmental and human health.