Abstract. The amount of sludge wastes from industrial, mining, domestic agriculture activities are about 60200 tons per year. The increasing of the waste will have significant impact towards environment and energy conservation. Many attempts have been made to incorporate sludge waste into brick for example fly ash sludge, sewage sludge, water sludge and ceramic sludge and advantages on the properties have been found but heavy metals leachibility will be the main concerned. Therefore, sludge waste is a potential alternative to convert into useful products as a building material that can alleviate the disposal problems. Therefore, in this study the characteristics of heavy metals were determined by using XRF. Four different mixing ratios of mosaic sludge waste at (0o/o, lyo,5oh, and 10%) were incorporated into fired clay brick. Each brick was fired in a heat controlled fumace at elevated temperatures of 1050C. The characteristic of heavy metals from the sludge waste were determined by XRF and the result show that the sludge waste is high in iron (Fe) and Zicronium (Zr) followed by Barium (Br), Chromium (Cr), Cadmium (Cd), Copper (Cu) andZinc (Zn). The leachability of heavy metals from the manufactured mosaic sludge brick were determined by using toxicity characteristic leachibility procedure (TCLP) and the results demonstrated that the culprit heavy metals were all complied to USEPA(1996) and EPAV(2005a).

Brick is one of the most common masonry units used as building material. Due to the demand, different types of waste have been investigated to be incorporated into the bricks. Many types of sludge have been incorporated in fired clay brick for an example marble sludge, stone sludge, water sludge, sewage sludge and ceramic sludge. The utilization of these waste materials in fired clay bricks usually has positive effects on the properties such as lightweight bricks with improved shrinkage, porosity, and strength. Therefore, the objective of this study is to incorporate different percentages of mosaic sludge and investigate heavy metals leachability from the mosaic sludge brick. Heavy metals leachability was conducted by using toxicity characteristic leaching procedure (TCLP). Physical and mechanical properties were also determined which are compressive strength, shrinkage, density and initial rate of suction. From the results obtained, it shows that fired clay brick with 5% of mosaic sludge obtained the best result with highest compressive strength and low initial rate of suction (18.76N/mm2 and 10.08 g/mm2) respectively. Nevertheless, all the other properties for all bricks incorporated with different percentages of mosaic sludge were also complied with the BS 3921:1985 standard. The results also demonstrated that the leachability of potential heavy metals in mosaic brick were complied with USEPA (1996) and EPAV (2005a) regulatory limit. In conclusion, mosaic sludge could be an alternative low cost material for fired clay brick as well as providing a disposal method for mosaic sludge waste.