ASSESSMENT OF THE QUALITY OF SLUDGE PRODUCED IN AQUACULTURE FARMS AND EVALUATION OF ITS USE
Keywords:heavy metals, aquaculture sludge, sludge quality, utilization of sludge.
The quality and potential uses of sewage sludge from three closed aquaculture systems and three pond aquaculture farms are discussed. The main objective of the study is to assess the concentrations of heavy metals (Cd, Cu, Cr, Ni, Pb, Zn, Hg) in aquaculture farm effluent sludge to determine whether the sludge is suitable for use as a fertilizer in agriculture and to evaluate the most effective way of using the sludge. The analysis of the data showed that the sludge from four farms was classified as Category I sludge and that the sludge from two farms was classified as Category II sludge and was suitable for use as fertilizer on agricultural fields. A review of the possible uses of the sludge has identified five use alternatives. In order to identify the most effective alternative, the multi-criteria analysis decision software DAM was used. The evaluation of the selected alternatives showed that the most advantageous use of sewage sludge is as a agricultural fertilizer or for composting and vermicomposting.