Investigating the Possibility of Using Water Treatment Plant Sludge in Brick Making

Sludge dewatering and disposal is one of the most important steps in management of water treatment plants. Today, due to rising raw material costs and limited in resources, reuse of waste is taken into consideration more than the past. The main objective of this study was to investigate the feasibility of using water treatment plant sludge in brick making. For this purpose, samples of bricks with different sludge to clay ratios were prepared and characteristics of each were studied. Results show that increase in sludge part, lead to increasing of bricks pores, as well as water absorption capacity and decrease the compressive strength, density and weight of bricks. In this regard, the minimum permissive bricks compressive strength of 80 Kg/m2 was achieved with 42% sludge to clay ratio. This ratio will be limited to 24% to allow maximum acceptable water absorption of 20%. Although water absorption is an important parameter for face bricks, but can be disregard (ignore) against compressive strength in load bearing walls. In this research by changes in the sludge ratio, various colors of bricks that makes it possible to use as face brick was generated. Bricks weight losses as well as reduction of building weight which use this type of brick is another result of the present study.