Monitoring of Composting Temperature and Assessment of Heavy Metals Content of Ouagadougou’s Urban Waste Composts
Dasmané BAMBARA1, Jacques SAWADOGO, Ablassé BILGO, Edmond HIEN, Dominique MASSE

Soils’ organic matter content can be improved with urban waste compost adoption. But these composts often include pathogens kept alive after temperature rise during composting and unwanted chemical elements such as heavy metals as well. Therefore, it’s necessary to assess temperature evolution, because factor of hygienizing of urban waste composts and know composts heavy metals contents as well, before agricultural valorization. This study determined temperature evolution and heavy metal content of six composts produced from mixtures of green waste, slaughterhouse waste and kitchen waste. Aerobic composting in piles was used for four months. Temperature measurement was performed using compost thermometer. Cadmium, copper, chromium, nickel, lead, zinc and arsenic were assayed by atomic absorption spectrometry. The results showed that the maximum temperatures varying from 53.7 ° C to 61.9 ° C were reached between 14th and 56th day of composting according to mixtures constituted. Several temperature peaks were noted after each turnaround, but their values were decreasing by time. Heavy metal concentrations varied from compost to compost, however, contents levels were well below in comparison with the thresholds set by the international standard NF U 44-051. Composts from various materials were the most contaminated. Temperature peaks reached could kill pathogens and hygienize the composts. Other wastes mixing formulas to be composted are to be investigated.

Full Text: PDF     DOI: 10.15640/jaes.v8n1a8