Optimization of municipal solid waste management strategy in Iskandar Malaysia using general algebraic modelling systems

Abstract

Municipal solid wastes (MSW) are the materials generated, collected and discarded of in municipal areas because of their no or less value to the generator. Thousands of tonnes of MSW are produced annually in Iskandar Malaysia (IM), and the rate continues to increase due to high population growth, high degrees of urbanization, and industrialization. This increase in the amount of MSW makes its effective management an issue of great concern because of the cost implications and the threat it poses to human health and the environment. Hence it is absolutely essential to search for a better strategy to manage it in an economically viable and environmentally friendly manner. Three mathematical optimization models using linear programmes were developed and implemented using relevant data of IM region. In view of that, this research developed and solved three mathematical models using general algebraic modelling system software as a tool. The research objectives are; (i) To develop a cost-effective strategy for MSW collection and transportation from points of generation to disposal/recovery for a typical IM region using linear programming minimizing cost. (ii) To develop a single period MSW utilization strategy for revenue generation from the recyclable components of MSW in IM using an optimization tool to maximize profit. (iii) To estimate the biogas to electricity generation potential of the organic components of the MSW in IM. The results show the optimal transportation cost of MYR 5.97 million per week. The MSW amount transported from municipals to landfills to achieve cost-effective outcome are Pasir Gudang to Tanjung Langsat (2452 metric tonnes), Kulai to Pekan Nenas and Seelong (512 and 1501 metric tonnes), Pontian to Pekan Nenas and Seelong (1739 and 2214 metric tonnes), Johor Bahru to Pekan Nenas, Seelong and Tanjung Langsat (1739, 7485 and 18 metric tonnes), Johor Bahru to Pekan Nenas, Seelong and Tanjung Langsat (1739, 6881 and 110 metric tonnes). The total trucks to each landfills sites are Seelong, 988, Pekan Nenas, 313 and Tanjung Langsat 141. The highest and lowest trips are from Johor Bahru to Seelong and Tanjung Langsat at 429 and 1 respectively. The results also show the minimized cost of sorting MSW into recyclable is MYR 572,000. The highest and lowest recycled components are organics and glass (46 and 19 metric tonnes) at sorting units 1 and 5 respectively. The minimized cost of electricity generated from MSW is MYR 143,000 per week. The decentralized model shows that the highest utilization of organic is at Kulai municipal (400 metric tonnes) and lowest at Pontian (50 metric tonnes). A cost saving from 2,157,777.40 before to 1,965,161.82 after minimization, which is 8.9% in reduction was achieved. The models are also viable for recycling and biogas generation.