Utilizing Coagulants from Industrial Waste for Treating Stone Cutting Wastewater Technical Feasibility and Parametric Optimization

Abstract

Abstract Treating waste by waste is an important concept in environmental sustainability. In treating wastewater containing suspended mineral particles (e.g. stone cutting and tile industries), flocculation sedimentation process is widely used, utilizing a commercial flocculent. Utilizing coagulant from other natural sources and industrial wastes can assist in waste management and in reducing the treatment cost.

This study aims at utilizing coagulants from wastewater (released by leather and aluminum coating industries) for treating stone cutting wastewater. A full literature review indicates that this innovative approach has not been investigated in previous research work.

After characterizing the wastewater, the effects of various operating parameters on wastewater treatment efficiency were investigated experimentally. Wastewaters (from the two sources) were mixed, then jar test experiments were performed. The effects of changing wastewater mixing ration and pH on the removal efficiency were investigated by turbidity meter and UV-spectrophotometry.

The optimum mixing ratio for treating stone cutting wastewater with wastewater from leather manufacturing (liming step) was found to be close 10%. It achieved a turbidity removal efficiency of 98.8%. A similar optimum value was obtained when wastewater from aluminum coating was utilized as a coagulant. However, the obtained removal efficiency was 90%. The removal efficiency changes with pH of the system. The best efficiency was obtained at alkaline conditions (with an optimum value of 9.5).

These experimental results were compared with similar experiments utilizing a commercial lime solution. A lower removal efficiency (91%) was obtained.

For the purpose of comparison, a lain sedimentation test was performed (without adding a coagulant). The obtained removal efficiency was 75%. Such a comparison emphasizes the technical feasibility of this novel process (utilizing wastewater as a coagulant).