Characteristics and management of landfill solid waste in Kumasi, Ghana

Frederick Owusu-Nimo of the Department of Civil Engineering, College of Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana recently conducted a study to examine the characteristics and management of landfill solid waste in Kumasi, Ghana

The design and performance analysis of landfill systems require information on the characteristics of landfill waste as well as the operational activities at the landfill site. There is however limited information on the characteristics of landfill waste in Ghana.

This study examined the waste characteristics and the operational management at the Oti landfill in Kumasi, Ghana. For the waste characterization, samples from different areas and depths of the landfill, representing different ages of deposition were used. Truck time studies, as well as spreading and compaction of offloaded waste at the landfill was also studied.

A logarithmic relationship was found between average unit weight and age of deposition. The high content of plastics (up to 58%) in the waste stream calls for recycling to prolong the life span of the landfill. The findings on the waste composition also has implications for landfill mining in the future.

The unit weight of the compacted waste ranged from 4.28 kN m−3 to 16.64 kN m−3 depending on the depth and age of waste deposition. The average compacted unit weight of 11.87 kN m−3 was higher than the estimated 8.83 kN m−3 used for the design of the landfill. The total volume of the void space available at the landfill will therefore be able to receive waste more than the estimated 15-year period. The compaction studies revealed that the compaction of waste was adequate, and that the number of compactor passes was directly proportional to the amount of waste offloaded.