The potential of energy recovery from Municipal Solid Waste in Kampala by incineration.

Abstract

Kampala's Municipal Solid Waste (MSW) is continuously increasing as a result of its growing population. This has put a strain on the land and electricity resources. This waste is largely disposed of at Kampala's only landfill located in Kiteezi, which has currently exceeded its capacity posing a waste management problem. Kampala, being the economic hub of the country, absorbs 58% of the country's electricity. The main goal of this research was to assess the technical and economic feasibility of incinerating MSW to generate electricity, using Kampala as a case study. The waste data was gathered by taking a sample of the garbage that was sent to the landfill. A proximate analysis was done to determine the moisture content, volatile matter, fixed carbon, ash content and the calorific value of the waste samples. The elemental composition of the waste was calculated using the results from the proximate analysis. The incineration plant design was based on a mass burn incineration plant where the design parameters were determined using thermodynamic equations and Peng Robison’s equations of state. The simulation was done using Aspen Plus and Aspen Hysys, components of Aspen Tech V10. The economic analysis was done with the assumption that the project was a Public Private Partnership (PPP) debt financed by 75% with an interest rate of LIBOR plus 5 % margin over a term of 15 years. The composition of the waste was largely organic (Food waste, banana peelings, garden waste, wood and waste fines) with an 80% composition. The Low Heating Value (LHV) of the waste was 6.1 MJ/kg with a moisture content of 25%. The calculated elemental composition of the MSW was 43.47% carbon, 5.52% Hydrogen and 41% Oxygen there was no nitrogen and sulphur in the waste and the ash content was 6.65% as shown from the proximate analysis. A simulation was done of mass burn facility combusting 220,000 tonnes of MSW per annum at a feed rate of 27 tonnes of MSW per hour. The plant is capable of exporting 815 kWh of electricity per tonne of MSW to the national grid powering 5,488 medium income households in Uganda. A capital investment of 157 million USD with the sale of electricity and a gate fee as the sources of revenue for a project running for 25years was considered. The resulting Net Present Value (NPV) was 34 million USD and with project Internal Rate of Return (IRR) of 12.9% and a payback period of 5 years. Waste to Energy (WTE) is economically viable in Kampala only with the sale of electricity and the charging of a gate fee as the sources of revenue.