Novel Lightweight Building Bricks Manufactured from Water Treatment Plant Sludge and Agricultural Waste

Novel lightweight bricks have been produced by sintering mixes of dried water treatment plant sludge and agricultural waste. Samples containing up to 40 weight percent rice husk have been sintered using a heating schedule that allowed effective organic burn-out. Rice husk addition increased the porosity of sintered samples and higher sintering temperatures increased compressive strengths. Materials containing 40 weight percent rice husk that were sintered at 1100 degrees C produced low bulk density and relatively high strength materials that were compliant with relevant Taiwan standards for use as lightweight bricks. This research was also evaluated the environmental safety of sintered products by the toxic characteristic leaching procedure (TCLP) concentration. The results indicated that TCLP concentrations of Cu, Zn, Cr, Cd, and Pb in the sintered products were lower than regulation thresholds.