FEASIBILITY OF USING A MIXTURE OF AN ELECTROPLATING SLUDGE AND A CALCIUM-CARBONATE SLUDGE AS A BINDER FOR SLUDGE SOLIDIFICATION

''Wastes treating wastes'' and resource recycling are the basic concepts of this study. In this work, two industrial wastes (an electroplating sludge and a water-purification calcium carbonate sludge) were obtained, mixed, and heated at 1000-degrees-C for four hours. The resulting material was then tested to determine whether it could be used as a binding material for solidification of the original electroplating sludge. It was found that the heat-treated sludge mixture did exhibit a binding capability in a cement-based solidification of its original electroplating sludge. In this study, a modified Taguchi method was employed for the experimental design of solidification. The heat-treated sludge mixture was used to partially replace (10 wt%, 20 wt%, or 40 wt% replacement) the ASTM Type I portland cement as a binding material. The solidified monoliths were then tested to determine their unconfined compressive strengths, TCLP leaching toxicity, and long-term chemical durability (by Multiple TCLP). Experimental results were found to be satisfactory. The concepts of ''wastes treating wastes'' and resource recycling are thus realized.