CEMENT-BASED STABILIZATION SOLIDIFICATION OF ORGANIC CONTAMINATED HAZARDOUS WASTES USING NA-BENTONITE AND SILICA-FUME

Cement-based stabilization/solidification of hazardous wastes containi ng heavy metal and organic has been investigated using chrome tanning waste. This work investigated the use of bentonite and briquette ash a s adsorbents for the organic components and heavy metals of industrial wastes, and silica-fume as an admixture to improve the solidified was tes with cement. Chrome tanning wastes containing up to 1.5% organic c arbon and 1.2% chromium were treated with sodium montmorilonite (bento nite) and briquette ash. Organic components and heavy metal of wastes were well adsorbed by the adsorbents. Solidification of the waste/clay /silica-fume mixes produced a monolithic mass with high strength and v ery low leaching of the organic compounds and the metals. This study h as shown that bentonite and briquette ash could be successful adsorben ts for the organic contaminant and heavy metals in industrial wastes a nd enabled them to be treated by cement-based solidification. Also the use of silica-fume to get high compressive strength and low penetrati on was highly effective. Cement-based solidification with the bentonit e, briquette ash, and silica-fume gave solid products which set rapidl y and were far stronger and more homogeneous than the sole cement-base d solidification. Leaching organic and metal from the stabilized produ cts were very low. The TOC was reduced by 60% to 78% for the wastes te sted compared with the conventional cement-based solidified waste, and the release of heavy metal was reduced by 52% to 70%.