Electrochemical mineralization of abattoir wastewater with continuous system

Abstract

This study aims to determine the effects of initial pollutant concentration level (1/1–1/4), flow rate (10–40 mL/min), NaCl concentration (0.1–1 M), pH (3–9) and current density (4.73–23.67 mA/cm2) parameters on the removals of total suspended solids, total organic carbon, chemical oxygen demand, total nitrogen and color for economic treatment of cattle-abattoir wastewater using mesh-type Ti/Pt anodes with continuous EO system. Total suspended solids, total organic carbon, chemical oxygen demand, total nitrogen and color analyses were carried out according to photometric method, catalytic oxidation method, closed reflux colorimetric method, nitrogen cell test method and platinum–cobalt method, respectively. The effluent chloride levels were analyzed according to the argentometric titration method. According to results, all operational parameters had an impact on removal efficiencies but the most effective parameters on energy consumption were NaCl concentration and applied current density. Although two possible system conditions were determined according to removal efficiencies the operating conditions with the lowest energy consumption are considered to be optimal. The optimum operating conditions were determined as NaCl concentration of 1 M, CD of 4.73 mA/cm2, initial pH of 7.03, reaction temperature of 25 °C and FR of 10 mL/min. Under these conditions removal efficiencies (%) for total suspended solids, total organic carbon, chemical oxygen demand, total nitrogen and color were found as; 98.28, 93.03, 97.44, 95.53 and 99.80, respectively. The energy consumption values were calculated as 2.42 kWh/kg COD and 19.43 kWh/m3. The approximate cost to treat 1 m3 wastewater was calculated as $ 6.43. The kinetic behavior abided by a pseudo-first-order model.