Characterizing market crop waste as feedstock for composting to reduce environmental pollution in developing countries

Abstract

Purpose Market crop waste (MCW) contributes significantly to the quantity of municipal solid waste generated in sub-Saharan Africa. These wastes, however, contain high levels of plant nutrients which can be harnessed through composting to improve soil organic matter and nutrient status of impoverished tropical soils.Method In this work, annual MCWs from two urban markets in Accra, Ghana were characterized by quantifying their seasonal availabilities, primary nutrients, heavy metals concentrations and level of microbial contamination to ascertain their suitability or otherwise for composting.Results Waste generated in the rainy seasons was higher than in the dry seasons. Primary nutrients sequestered in the MCW collected were 211.1 kg N, 1.84 kg P and 89.66 kg K for both markets. Feedstock quality analysis showed heavy metal levels in the MCW were far below the contaminant levels. Moisture content of vegetable and fruit waste was 74.34 - 90.46% and far above the desired level of aerobic composting. Pathogen levels of 5.92 CFU/g E. coli and 5.41 CFU/g Salmonella in cocoyam leaves; 6.27 CFU/g total coliform and 4.74 CFU/g Enterococcus in cabbage were detected and found to be above the maximum contaminant level as per USEPA standard.Conclusion Use of cassava, plantain peduncle and corn husk as bulking agents with vegetable and fruit waste as N, P and K sources should serve as feedstock for good quality compost production.

Keywords

• market crop waste
• feedstock
• composting
• nutrient flow
• seasonal variation