ORALS

Treatment and adequate disposal of slaughterhouse wastewater (SWW) is a worldwide economy and public health necessity. SW contains elevated amounts of organic matter and salts. Typical parametrical analyses include pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TN), total phosphorous (TP), total organic carbon (TOC) and total suspended solids (TSS) [2]. After preliminary treatment, the electrochemical processes such anodic oxidation (AO) and electrocoagulation (EC) have been considered an alternative technology for the treatment of SWW. In this study, a real beef slaughterhouse wastewater presented the following characteristics: TOC (1150 mg L–1), COD (4320 mg L–1), TP (25 mg L–1), TN (72.28 mg L–1), TSS (1433 mg L–1) at pH 7.18 and conductivity of 2.79 mS cm–1. Bright red color was observed at 416 nm (1.24 A.U.) and the presence of coliform bacteria was confirmed (> 1600 MPN). AO and EC tests were carried out in a single open cell compartment in batch operation mode with constant stirring to ensure mass transport of the oxidant specie towards/from the anode to the bulk. AO was assessed using two different dimensionally stable anodes (DSA) type anodes: i) Ti/IrO2/Ta2O5 coating (DSA-O2) ii) Ti/Ru0,3Ti0,7O2 (DSA-Cl2). AISI 304 stainless steel plate was used as cathode. EC was evaluated using iron and aluminum electrodes (anode and cathode). The best operating conditions were found at current density of 20 mA cm–2 without supporting electrolyte. TOC, COD and TP removal efficiency were 79.77% and 78.62 %; 89.22% and 79.4%; 96.0% and 64% using DSA-Cl2 (Ti/Ru0,3Ti0,7O2) and DSA-O2 (Ti/IrO2/Ta2O5), respectively. Moreover, a complete discoloration and disinfection were achieved. Electrochemical oxidation test at best operating conditions gave energy consumption and specific energy consumption values for TOC, COD and TP using DSA-Cl2 and DSA-O2 of 24.5- and 26.5-kW h m–3-, 27.1- and 28.9-kW h kgTOC–1-, 7.14- and 6.88-kW h kgCOD–1 and, 1531.25- and 1104.17-kW h kgTP–1, respectively.