Use of biochar and Moringa oleifera in greywater treatment to remove heavy metals and contaminants of emerging concern

Ivan Kozyatnyk, Mary Njenga, Use of biochar and Moringa oleifera in greywater treatment to remove heavy metals and contaminants of emerging concern, Bioresource Technology Reports, Volume 24, 2023, 101615, ISSN 2589-014X, https://doi.org/10.1016/j.biteb.2023.101615. (https://www.sciencedirect.com/science/article/pii/S2589014X23002864)

This study investigated the combination of biochar derived from carbonized local feedstock and Moringa oleifera seed extract-based flocculant, a novel combination in the context of greywater treatment missed in the previous studies, with a focus on the removal of organic contaminants (caffeine, chloramphenicol, trimethoprim, carbamazepine, diclofenac, and bisphenol A) and heavy metals (Cr(VI), As(III), Co(II), Ni(II), Cu(II), Zn(II), and Pb(II)). The research focused on the optimization of dosage, application procedure, and relevance to greywater (presence of humic acids, clay, and surfactants). The order of application was found to impact organic compound removal, with the initial application of the flocculant, followed by biochar, being the more effective approach. The combined use of biochar and flocculant positively impacted the removal of heavy metals but impeded the removal of organic pollutants. The presence of humic acids, clay, and surfactants affected the flocculation process, which impeded the removal of heavy metals and organic pollutants.

Keywords: Adsorption; Flocculation; Sustainable solutions; Water contamination; Developing countries