UTILIZATION OF INDUSTRIAL BYPRODUCT AS RAW MATERIAL IN CONSTRUCTION INDUSTRY- A REVIEW

A large quantity of sludge rich in nutrients and microorganisms is generated every year from water and wastewater treatment plants, the final destination of which affects the environment. Generally, dewatered sludge is disposed of by spreading on the land or by land filling. However, space limitations on existing landfill sites and problems of waste stabilization have prompted investigation into alternative reuse techniques and disposal routes for sludge. A more reasonable approach is to view the sludge as a resource that can be recycled or reused. Many researchers have exploited the reuse of lime sludge from water treatment plant and sewage sludge ash as an inexpensive source of soil stabilizer in sub grade stabilization and soft cohesive soil respectively. Sewage sludge pellets (SSP) has replaced sand in concrete manufacturing for pavements. The use of SSP as substituting material in raw mix formulation in Portland cement manufacturing has been studied by many researchers. Experimental results showed the feasibility of the partial replacement (15 and 30%) of cement by sewage sludge ash (SSA) in mortars. This paper highlights the potential of dried sludge, sludge pellets and sludge ash in various building materials for construction.