Characterization and experimental investigation of powdered filtration sludge for potential utilization in...

Rapid sand filtration is typically used at water treatment plants to remove the fine suspended solid particles from the raw water. Backwashing of exhausted filter beds inevitably generates large volume of filtration sludge in water treatment plants. In this study, filtration sludge is collected, dried and crushed to powder, then passed through 90 µm sieve to get powdered filtration sludge (PFS) which is then characterized and utilized without energy intensive process of calcination. The PFS is blended with cement up to 20% and investigated for various properties to assess the possibility of its utilization in construction industry. Ordinary Portland cement (OPC) mortar or control mortar when substituted with up to 15% PFS has compressive strength above 33 MPa at 28 days and above 41 MPa at 90 days and setting times within prescribed limits. OPC blended with PFS up to 15% conforms various specifications desired for use in different construction practices especially where early strength is not essential. Utilization of filtration sludge as partial cement replacement in mortar would provide a beneficial and sustainable disposal alternative. Simultaneously it will reduce the cement consumption depending on the extent of its utilization. Consequently, it would help in conserving the natural resources, reducing the carbon emission and its related impact on the environment.