Characterisation and Composting of Tannery Sludge

Abstract

Tannery industries create serious environmental problems especially in terms of polluting organic effluent and hazardous solid waste as a result of hides and skin processing. It is very important that tannery waste in the form of sludge is managed in an environmentally sound manner. This study focuses on the characterisation of tannery sludge and its development as a composting material. The results show that electrolytic conductivity (EC) of the compost was 2.0 mS cm-1, pH 6.6 and C/N ratio of 16. Total concentrations of chromium, zinc, copper, lead, and cadmium in dry compost were reduced and complied with the standards of the Canadian limits, thus classifying them excellent for making the compost suitable for use as a fertiliser and soil conditioner. The compost characteristics indicated that it was mature, and the germination index for Chinese cabbage was 82.5 %, which may suggest absence of phytotoxic compounds.