Investigation of environmental impact of oil refinery industrial sludge disposal process by life cycle assessment approach using CML-Baseline impact assessment model

Introduction: The sludge produced in the oil refinery is very harmful due to the significant volume and complexity of the compounds, and its reasonable disposal is very important for environmental protection and sustainable development. During the effluent treatment process in the oil refinery, contaminated industrial sludge containing toxic substances is produced, which contains polyaromatic hydrocarbon compounds and is classified in the group of hazardous wastes.Material and methods: In this study, the life cycle evaluation of disposal methods in two scenarios of landfill and incineration on industrial sludge of oil refinery in Iran has been investigated. Using life cycle assessment softwareand openLCA with CML-Baseline Impact Assessment Model, different environmental impact categories were examined and using weighting and dimensionless method of each effect class in the two defined scenarios, the best scenario has been identified in terms of the environment.Results and discussion: The results from 11 categories including acidification, climate change, reduction of abiotic resources, related to both fossil fuels and factors affecting final reserves, toxicity drinking water, seawater, and soil, eutrophication, human poisoning, ozone layer depletion, and photochemical oxidation have been evaluated. The results showed that the least environmental effects on indicators of human and plant species health are related to the landfill scenario. The sludge incineration scenario, which is sent directly to the incinerator, has been selected as the worse scenario with the highest emissions of carbon dioxide, methane and nitrogen oxides into the environment.Conclusion: The results of dimension lessness in the two studied scenarios showed that Scenario 1 (Landfill) with a value of 2.94 × 10 -6 and Scenario 2 (waste incineration) with a number of 5.42 × 10 -6 had the most and the least destructive effect on the environment, respectively.