Mathematical modeling in municipal solid waste management: case study of Tehran

Empirical analysis of cost-effective and equitable solid waste management systems: Environmental and economic perspectives

The solid waste management (SWM) system is in a transitional phase in developing economies, and local municipalities and waste management companies are stepping toward integrating a waste treatment approach in the scheme of waste handling. However, there is an urgent need to explore cost-effective techniques, models, and potential revenue streams to sustain the state-run waste sector self-sufficiently. The proposed SWM model aims to support the local waste sector in Islamabad, the capital city of Pakistan, with 100% service area coverage to attain environmental and economic sustainability by defining dedicated waste collection streams to ensure quality material recovery under a cost-effective approach and modality. The innovative approach is applied to allocate the tonnage to various streams as per the city's current land use plan. The estimated/cost of the cleanliness services will be USD13.1 million per annum with an estimated per ton cost of USD 23. The establishment of the proposed material recovery facility (MRF) will process about 500 t/d of waste to produce 45 t/d compost and recover 130 t/d of recyclables. The environmentally friendly model saves 2.4 million tons of CO2‒eq/month from composting and recycling. The average economic potential from MRF and debris-crushing plants, including environmental benefit value, is calculated as USD 3.97 million annually. Recovery of services fee (70%) for various collection streams based on city land use and socio-economic conditions will generate revenue of USD 7.33 million annually. The total revenue will be USD 11.31 million (86% of total annual expenditures) to track the sector's self-sufficiency. To successfully reach the Sustainable Development Goals (SDGs) and Nationally Determined Contributions (NDCs), engaging the private sector from environmentally advanced economies to collaborate in the waste sector to enhance local technical capabilities is recommended.

An Optimization Model for the Design of a Sustainable Municipal Solid Waste Management System

Solid waste management is critical to sustainable, healthy, and eco-friendly cities and societies. In developing countries, only a small percentage of municipal solid waste is disposed safely, while the majority remains in the streets or disposed in open landfills. Most countries seek to establish effective and efficient solid waste management system (SWMS) that can handle and dispose of the daily generated waste at minimum cost and in a sustainable manner. Those systems usually consist of waste sources, waste collection stations, landfills, incinerators, and recycling plants, in addition to the transportation system that integrates the different sub-systems. The problem facing decision-makers while designing or reconfiguring a SWMS is to determine the optimal supply chain network design for such systems in a way that ensures the treatment and disposal of all daily generated waste at the lowest cost. In this context, this paper aims to develop a generic optimization model suitable for application in SWMS optimization in developing countries. A new mixed-integer linear programming (MILP) model is formulated for a SWMS configuration that integrates waste generation sources, collection/transfer stations, recycling plants, incinerators, and landfills. The proposed MILP model is formulated to determine the optimal number and locations of the different facilities, and the optimal flow of waste in the system that minimizes the net daily cost incurred in the system. The model has been applied in a case study on the SWMS in Fayoum Governorate, Egypt. The main contribution of this research refers both to the theoretical development of a generic MILP model that can be applied to optimally design the SWMS in developing countries, and to its operational counterpart, as per the design solutions provided in the SWMS of Fayoum Governorate (Egypt).

Medical waste management during coronavirus disease 2019 (COVID-19) outbreak: A mathematical programming model

Municipal solid waste (MSW) directly impacts community health and environmental degradation; therefore, the management of MSW is crucial. Medical waste is a specific type of MSW which is generally divided into two categories: infectious and non-infectious. Wastes generated by coronavirus disease 2019 (COVID-19) are classified among infectious medical wastes; moreover, these wastes are hazardous because they threaten the environment and living organisms if they are not appropriately managed. This paper develops a bi-objective mixed-integer linear programming model for medical waste management during the COVID-19 outbreak. The proposed model minimizes the total costs and risks, simultaneously, of the population's exposure to pollution. This paper considers some realistic assumptions for the first time, including location-routing problem, time window-based green vehicle routing problem, vehicles scheduling, vehicles failure, split delivery, population risk, and load-dependent fuel consumption to manage both infectious and non-infectious medical waste. We apply a fuzzy goal programming approach for solving the proposed bi-objective model, and the efficiency of the proposed model and solution approach is assessed using data related to 13 nodes of medical waste production in a location west of Tehran.