Primary treatment of fishery wastewater using chemical and natural coagulants

Abstract

The Peruvian fishing industry is responsible for generating large volumes of effluents, whose treatment is complicated due to their high content of salts, organic matter and total suspended solids (TSS). The coagulation-flocculation method, utilizing chemical agents, has been employed for this purpose due to its efficacy. However, given that its use has negative impacts on health and the environment, the search for sustainable alternatives is a priority. In that sense, the objective of this study was to evaluate the efficacy of natural coagulants (chitosan and Moringa oleifera seeds powder) and chemicals (ferric chloride) to reduce total dissolved solids (TDS) in fishery wastewater. To that end, coagulant solutions were prepared, wastewater samples were collected to perform jar tests based on the established operating conditions, and finally, the reduction percentages were calculated. The results showed that natural coagulants are more effective than chemical coagulants to reduce TDS. Specifically, the application of chitosan and Moringa oleifera seeds powder generated maximum reductions of 98 ± 0.71% and 86.98 ± 1.92%, respectively, at a dose of 160 mg/0.5 L, while ferric chloride produced a maximum decrease of 83.64 ± 0.14% at a dose of 120 mg/0.5 L. Therefore, those findings support the idea that natural coagulants represent an effective and sustainable way to reduce physicochemical parameters from water.