Metal remediation and biodegradation potential of earthworm species on municipal solid waste: a parallel analysis between Metaphire posthuma and Eisenia fetida

Abstract

Information on vermicomposting with Metaphire posthuma is scanty. This paper, therefore, aims to evaluate the bioconversion efficiency of this species against Eiseniafetida. For comparative analysis, different combinations of municipal solid waste (MSW) and cow dung were used as substrates. The contents of total N and availability of P, K, and Fe increased significantly in both Metaphire and Eisenia systems which was accompanied by substantial reduction in pH and total organic C. Both species exhibited similar levels of urease activity and microbial respiration. Moreover, bioavailability of heavy metals (Pb, Zn, Mn, and Cu) was reduced substantially during vermicomposting, irrespective of the earthworm species. In contrast, each species was distinguished by the enhancement either in microbial biomass C and phosphatase activity (Eisenia) or in humification and fulvic/humic acid C (Metaphire). The overall results suggest that indigenous earthworm, M.posthuma could be utilized as a successful candidate for bioprocessing of toxic wastes.

Keywords: Metal accumulation; Metaphire posthuma; Municipal solid waste; Nutrient recovery; Vermicompost.