Chemical And Biological Characteristics Of Some Marketed Solid Waste Composts In Ghana

ABSTRACT The study assessed the chemical and biological characteristics of composts made from municipal solid waste in Accra and agricultural waste in Kade in Ghana. In Accra, compost samples were taken at residential level (Household composting), decentralised community level (AsieduKeteke composting facility) and at large-scale metropolis level (Teshie composting plant). The compost samples from Kade were produced at the University of Ghana Agricultural Research Station. Composting operations at Teshie and Asiedu-Keteke were from mixed feed stock of organic material, newspapers, bottles, plastics, etc. and represented composting o f un-segregated solid waste. The Household compost was produced from kitchen waste, whilst the Kade compost was produced from agricultural wastes (a mixture of cocoa pod husk, poultry droppings and saw dust). The Household and Kade composts were, thus, from purely organic sources. Public interest in composting in general was also assessed by way of questionnaires. The results indicated that the nutrient value, mainly nitrogen, phosphorus and potassium in the Accra composts, which were from municipal solid waste (MSW) were low compared to the compost from Kade, which was from agricultural waste. The differences in nutrient value reflected differences in feed-stocks for the composting. The composts from the mixed waste stream (Teshie and Asiedu-Keteke) did contain higher concentrations o f heavy metals such as * lead and cadmium compared to the composts from pure organic sources (Household and Kade). However, the concentrations of the heavy metals found in the mixed waste composts, were not of levels that would pose significant health risk. The Asiedu-Keteke composts were found not to be  matured and thus, may have restrictions for its use, particularly, for crop cultivation. All the other composts studied were found to be matured. The social survey indicated that respondents were less familiar with MSW derived composts in comparison to their knowledge on animal manure or yard waste composts. However, there was a potential for a positive public response to solid waste composting.