Kinetics Studies on the Coagulation of Abattoir Wastewater Using Groundnut Shell Extract as a Natural Coagulant

Abstract

This paper investigated the use of extract from groundnut shells as a natural coagulant for the reduction of turbidity in abattoir wastewater using the coagulation process. The ideal concentration of NaCl for coagulant extraction was established through a series of jar tests. The effects of process variables of coagulant dosage (1-5 g/L), settling time (0-60 min), pH (2-10) and temperature (298-318 K) on the turbidity reduction efficiency were examined using a bench-scale jar test. At an optimal condition of 4g/L, pH 8, temperature of 318K, and settling period of 20 minutes, a reduction efficiency of 94.33% was achieved. The Second-order per-kinetic theory of Von-Smoluchowski’s was used for kinetic evaluation at temperatures of 298 K, 308 K and 318 K. At a temperature of 298 K, the experimental data fit perfectly into the Von-Smoluchowski second-order per-kinetics theory, with a correlation coefficient of 0.952, coagulation rate constant of 0.00002 L/(mg.min), collision efficiency of 8.703exp12 and coagulation time of 48.27 min, establishing that the rapid coagulation theory holds true for the coagulation of abattoir wastewater using groundnut shell extract and under the experimental conditions. As a result of the findings, it is proposed that groundnut shell extract, which is readily available and environmentally safe, is effective for turbidity reduction of sewage water and can be used as an alternative to chemical coagulants for the pre-treatment of abattoir wastewater.