A mathematical model for improving solid waste disposal in Dar es Salaam

Dar es Salaam's rapid population and industrial growth is causing high increase in solid waste generated. This in turn causes severe environmental degradation and pollution problems. The increase in amount of uncollected solid waste is being recognised as a major public health problem. It is estimated that about 1772.2 tons of solid waste is generated per day in Dar es Salaam. Out of this amount, only 8% is disposed. This leaves a lot of undisposed waste, which is a problem. Factors causing this low waste dispose in Dar es Salaam include: 1) insufficient information on solid waste management, 2) luck of proper infrastructure for safe containment or disposal, 3) inadequate monitoring and enforcement of regulations, 4) inadequate collection, and 5) inadequate public awareness of the risks to health. To improve solid waste collection in Dar es Salaam, a deterministic multi objective programming model has been developed and applied in this study for planning a solid waste management system. A short-range planning model is also developed in this work for immediate planning if there is a need to do so. For example when there is seasonal increase in amount of waste, the manager could use this model to incorporate the changes in daily collection routine. The model results show that the collection cost can be reduced by 35% if transfer stations and collection points are properly planned in the collection process. The results also show that the current operating system can increase collection rate by about 4% without extra fund if the model suggestion is implemented.