Fate of some heavy metals in the composting of the urban solid waste produced in Lome,Togo

摘要

The aim of the present work is to assess the balance of some heavy metals during the composting of urban waste in Lome. Heavy metals constitute problems in waste management because of their multiple sources and their potentially high toxicity. Wastes were sieved to eliminate the fine fraction and set in windrows for composting and after maturation the sieved-compost was chemically characterized. The fraction of the super fines, that is, with a particle size less than 10 mm, contributed 30 to 56% of the average contents of metals in compost. Sorting of wastes into various fractions such as plastics, hazardous materials, glass, miscellaneous combustible material, metals, and super fines lowered the metals content in compost by about 80%. Elimination of super fines and sorting of urban waste before composting are means to reduce the content of heavy metals in composts.