Phytotoxicity and cost-effectiveness analysis of palm oil wastewater treated with magnetic cationic starch flocculant

Abstract

Toxicological issue on wastewater treated with conventional and starch modified with synthetic cationic monomers flocculants has become a major concern. Thus, selection on greener and low-cost monomer is needed. The present study assessed and compared the phytotoxicity of starch modified with protein extracted from Moringa oleifera (M. oleifera) seed cross-linked magnetic nanoparticles (MagCS) on germination index (GI), toxicity unit (TU), total chlorophyll, and carotenoid content of mung bean seeds over alum, polyaluminum chloride (PAC), polyacrylamide (PAM), M. oleifera, and cationic starch (CS). The concentration of palm oil mill effluent supernatant treated with these flocculants were varied from 25 to 100%. The result shows that MagCS has 53.33% GI at 100% concentration; meanwhile, alum shows the lowest GI of 13.33% at the same concentration. The TU of MagCS is also shown to be at the lowest level (TU = 0.98); meanwhile, alum is the highest (TU = 15.93). The usage of MagCS also enhanced the photosynthetic process based on high content of chlorophyll and carotenoid pigment. This study also evaluated and compared the economic feasibility of flocculants and based on cost-effectiveness model, MagCS has potential to replace conventional flocculants due to its superior flocculation performance. In conclusion, starting with the most desirable, the flocculants were ranked as follows: MagCS > CS > M.oleifera > PAM > PAC > alum.