Coagulation-based wastewater treatment using chitosan extracted from exuviae of <i>Tenebrio molitor</i> and <i>Sphenarium purpurascens</i>

ABSTRACT Chitosan, a biopolymer, has attracted increasing attention as a sustainable alternative to conventional coagulants for wastewater treatment. In this study, chitosan extracted from exuviae of Tenebrio molitor and Sphenarium purpurascens was evaluated as a natural coagulant–flocculant for domestic wastewater. The effects of sources, doses, and pH on total suspended solids (TSS) and soluble chemical oxygen demand (sCOD) removals were assessed using real wastewater. High removal efficiencies of sCOD and TSS were achieved under acidic conditions, with chitosan from S. purpurascens showing slightly higher overall performance. Anaerobic biodegradability tests indicated limited degradation of chitosan, with no significant enhancement of biogas production. Results obtained in coagulation–flocculation tests highlight the potential of insect-derived chitosan as a sustainable alternative to conventional coagulants for wastewater treatment applications, contributing to resource-efficient and environmentally compatible treatment strategies.