Sewage Sludge and Red Mud as Brick Materials

Sludge resulting from wastewater treatment plants has disposal problems. Generally, this sludge is disposed by spreading on the land or by landfilling. However, for cities which are urbanized, sludge disposal by landfilling might not be appropriate due to limited area. Incineration can create very big amount of ash and that must be disposed by other means. With growing social awareness about toxic incinerator emissions and the increasing concern over the disposal of sludge onto agricultural land, it seems obvious that the recovery of sewage sludge as a building and construction material can be considered as an important step in the right direction. The use of sludge in construction industry is considered to be the soundest option both economically and environmentally. Sludge produced in the treatment plant can be effectively used in manufacture of bricks and the quantity of waste produced can be minimized. Red mud (RM) is a by-product from alumina production through Bayer process. The production of RM was estimated about four billion tons. Recycling of this big amount of alkaline waste is considered to be a serious challenge. Utilizing RM as a raw material to make bricks seems like a promising option. Also, there are substances in RM which can lower the sintering temperature of bricks. The current research focuses on the effective utilization of sewage sludge and red mud in clay bricks to minimize the impact of massive dumping of these materials on the environment. Also the study aims to create a material with quality and economy. From the study, it is understood that even though the high organic content will decrease the mechanical properties, it can give out bricks which are environmentally sustainable. As these bricks are third class bricks, it can be effectively used in non-load bearing structures.