Risk Assessment of Urban Waste Management through EFMEA and TOPSIS Methods (Case Study: District 6 of Tehran Municipality, Iran)

Background: We assessed and ranked environmental risks in the mechanized urban waste collection and storage systems in Tehran municipality (Iran) to locate safe areas for the establishment of these systems. Methods: This descriptive-analytical study first identified and classified the effective factors in locating the mechanized systems of the studied district in seven criteria (socioeconomic, physical-spatial, hydrological-climatic, geological, and three passive defenses including dispersion, lifeline, and high-risk facilities). Risk factors were evaluated using the FMEA technique and prioritized using the TOPSIS method. Results: The FMEA results classified the identified passive defense and environmental risks into three levels (high, medium, low), with 69% of the risks at the low level, 17% at the medium level, and 14% at the high level. The TOPSIS ranking results identified Distance to nearest fire station , Distance to a fault and Distance to power substation as the highest risk factors with the similarity to ideal solution (cli)values of 0.861, 0.774 and 0.771, respectively, as well as Distance to gas pressure-reducing stations (cli = 0.134) as the least important risk factor. Conclusion: New urban waste collection and storage stations in the studied district should be established according to the population of the areas and at a suitable distance to the nearest fire stations. Further, locating and designing these systems in wide open spaces is highly essential.