| Popis: |
Analysis of the chemical components of Municipal solid waste (MSW) indicated that the presence of high concentrations of toxic heavy metals. The aim of this study was to select the best leaching condition, in order to generate a compost product, which adheres to the environmental standards for safe use. To determine the role of organic acids produced in the bioleaching process, chemical leaching experiments were compared using inorganic (H2SO4) or organic acids (oxalic, and gluconic acids). These results revealed that addition of H2SO4 correlated with a lower retained yield when comparing with addition of the other acids. Bioleaching was then studied by culturing fungi on the MSW. Addition of Aspergillus niger correlated with an efficient removal of heavy metal elements. The effect of pH was also determined and assays at pH 5.5 using a clay medium (32.4%) or at pH 2.5 using a sorghum medium (28%) were characterised by a lower retained yield. In the above conditions, we looked at elemental ions which have been deemed beneficial to the environment (P and K) and those which are toxic (Cd, Cu,Cr, Ni, Pb and Zn), these elements were measured in the solid fractions. |
