Characterization of South African Brewery Wastewater: Oxidation-Reduction Potential Variation
Siphesihle Mangena Khumalo, Babatunde Femi Bakare, Sudesh Rathilal, Emmanuel Kweinor Tetteh
Abstract
Conventional wastewater treatment processes are challenged by the need to effectively reduce pollutant loads before disposal or reuse, as the composition and concentration of contaminants in brewery wastewater change with time. This results in the variation of the oxidation-reduction potential (ORP) of the affluent. Hence, the current study is aimed at the application of ORP as a real-time tool to monitor brewery wastewater quality. Other physicochemical parameters of the local brewery in South Africa investigated included temperature (T), pH, conductivity, turbidity, total chemical oxygen demand (TCOD), soluble chemical oxygen demand (SCOD), particulate chemical oxygen demand (PCOD), total solids, orthophosphate, ammoniacal nitrogen, total Kjeldahl nitrogen (TKN), total nitrogen (TN), nitrate, and nitrite nitrogen. It was found that the ORP decreased (135 to −305 mV) with an increase in alkalinity (pH 4.4 to 12.2) with linear regression coefficient fit (R2 = 0.9994). The ORP facilitated the wastewater nutrient constituent degradability which improved the water quality. Furthermore, the high organic content of the brewery wastewater was found as measured by total COD (3447–11,813 mg/L). This suggests remediation before reuse of the brewery wastewater will require a robust integrated wastewater treatment process.