Use of emergent moringa-based coagulant/flocculant for water treatment with verification of composition and toxicity of the produced sludge: water treatment with Moringa and toxicity of the sludge

ABSTRACT

The present study aimed at evaluating the efficiency of conventional water treatment processes using the natural coagulant Moringa oleifera Lam, with and without shell, for the treatment of raw water captured in the Poxim River, Aracaju, state of Sergipe, Brazil. After this evaluation, the chemical composition of the sludge and its toxicity was analyzed. The stages of coagulation/flocculation and decanting (30 and 60 min) were performed in jar test with the coagulant, followed by rapid descending filtration. The effectiveness of the coagulants was analyzed by the characterization of the water in dosages of 100, 200, 300, and 400 mg.L^-1, according to physicochemical analyses, including the parameters pH, apparent color, and turbidity. The treatment sludge, in both situations under study, was characterized in relation to the composition of protein, starch and lipid, in addition to verifying the toxicity of the residue by the growth and germination of Lactuca sativa. As a result, moringa showed potential in the treatment of water for human consumption, mainly the extract of moringa in shell, with an optimal dosage of 300 mg.L^-1 for both color and turbidity parameters. Regarding pH, the treatments did not promote significant variation in the raw water values. In terms of sludge characterization, the presence of lipids and proteins was verified, but not that of starch. In addition, the sludge residue was considered nontoxic to the environment.

Keywords:
natural coagulant; water quality; human consumption; Lactuca sativa