Study on feasibility of reutilizing textile effluent sludge for producing concrete blocks

• Textile effluent sludge (TES) was recycled for producing concrete blocks.
• Lime pretreatment methods were adopted to remove the ammonium in TES.
• TES reduced strength and increased drying shrinkage of concrete blocks.
• Acceptable performance for concrete blocks containing 10% TES was achieved.
• Toxic trace metal in TES could be stabilized in concrete blocks.

With an increasing interest in recycling and reusing waste, there is a need to carry out research on exploring ways to transform industrial wastes into construction materials. This paper attempts to explore the feasibility of reutilizing textile effluent sludge (TES) for producing concrete blocks with a pretreatment step. The lime-based pretreatment process was adopted to remove ammonia in TES which had been found to lead to bad odor and strength loss of the concrete blocks. The concrete blocks were prepared with an aggregate to cement ratio of 12, 10 and 6. The pretreated TES was adopted to replace the fine aggregate at a mass ratio ranging from 0% to 30%. The compressive strength and drying shrinkage values were determined to evaluate the performance of concrete blocks containing TES. The results indicated that the lime-based pretreatment process can lower the ammonia concentration in TES significantly. The concrete blocks with a lower TES content and lower ammonia concentration had higher compressive strength and better volume stability. When the TES content in the concrete blocks was about 10%, the concrete blocks with an aggregate to cement ratio of 10 can satisfy the minimum strength requirement for non-load bearing applications. Meanwhile, the result of leaching test indicated that the toxic trace metals present in textile effluent sludge could be stabilized/solidified and metal leaching from the concrete blocks is not a concern.