The Effect of Extract Tannins from Spent Coffee Ground on Waste Water Treatment

Abstract

Green extraction processes to obtain high value bioactive compounds from raw natural materials and wastes has gained attention the past few years. In the present study, we investigated a Natural Deep Eutectic Solvent derived from two natural products, namely choline chloride and glucose as a potential solvent for the extraction of tannin compounds from spent coffee ground(SCG). A tannin was used as coagulant with the Poly aluminium chloride(PAC) as flocculant. Initially, jar test experiments were conducted with a varying dosage of coagulant and initial pH. Next, tests were carried out with different values of PAC dosage, flocculation time as well as sedimentation time to find out the optimum condition for colour removal. The supernatant layer of treated leachate from each test was analysed for colour, pH and conductivity. At optimum leachate pH of 5, experiments with 3 minutes flocculation time and sedimentation time of 10 minutes resulted in the highest colour removal (81.8%) at coagulant dosage of 100 mg/L, with 1 mg/L PAC being added. Coagulation flocculation system of as tannin-based coagulant with PAC as flocculant showed the promising result in decolourisation of wastewater.