Integrated Waste Management: Adding Value to Oil and Gas Industry Residues Through Co-processing

Abstract

In developing countries, the sustainable management of materials into a circular economy framework is conditioned by several constraints, being economic limitations one of the most relevant. Integrated waste management could effectively aid in overcoming them. This work presents an exhaustive analysis from both economic and environmental points of view addressing the selection and design of treatment alternatives for the integrated management of urban and industrial wastes. We propose a mixed-integer mathematical programming formulation to determine the optimal set of treatments to convert wastes into energy, marketable products or innocuous materials, and we endorse the environmental performance through a life cycle analysis. In our case study, urban wastes include sewage sludge and municipal solid waste, while industrial wastes come from two sources: drill cuttings (an important oil and gas industry residue) and seasonal pomace waste from fruit processing. Treatment alternatives comprise anaerobic digestion, composting, recycling, bioremediation, compost amendment, thermal desorption and final disposal in landfill. Results for different scenarios show that even though the most profitable alternative is to dispose drill cuttings in landfills while processing organic wastes by anaerobic digestion, integrated management using biological treatment alternatives provides a more sustainable and still profitable strategy. We also demonstrate that the process integration increases the profitability and reduces the environmental impact significantly when compared with separate treatment alternatives for waste streams.