Synthesis and evaluation of the efficiency of a fly ash-derived coagulant for industrial wastewater pre-treatment

Abstract

The development of new materials for environmental treatment and the reuse of industrial waste have been receiving attention, with the aim of promoting sustainable development. In this study, fly ash from a thermal power plant was utilized to synthesize a coagulant. The synthesized coagulant was applied in the pre-treatment of centralized industrial wastewater using the coagulation-flocculation process. The optimal dosage of coagulant was determined through Jartests in the laboratory. Then, coagulation-flocculation experiments were conducted using a laboratory-scale model, comparing the fly ash-derived coagulant with commercially available polyaluminum chloride (PAC). Jartest results demonstrated that the fly ash-based coagulant achieved removal efficiencies of 85.94% for turbidity and 90.49% for suspended solids (SS) at a dosage of 7.0 mg/L and pH 8.0. Model-scale experiments showed that the fly ash-based coagulant at the selected dosage, and PAC at 500 mg/L, achieved removal efficiencies of 61.8% and 39.08% for turbidity, 52.67% and 51.42% for SS, and 57.79% and 23.53% for COD, respectively. These results indicate that fly ash from thermal power plants can be effectively reused as a coagulant, offering a promising solution for wastewater pre-treatment and contributing to the reduction of environmental impacts from coal-fired power plant waste.