Assessment of Pathogen Reduction Potential of an Anaerobic Digester containing Winery Wastewater

Abstract

In this study, assessment of the pathogenic bacteria reduction capacity of an anaerobic digester (AD) containing winery wastewater (WWW) was carried out. Samples were collected from a winery drainage system (influent) and a bioreactor after digestion (effluent) at the Agricultural Research Council (ARC), Stellenbosch, South Africa. Qualitative analysis was by means of pH, optical density (OD) and most probable number (MPN) techniques. The isolates were identified using biochemical and polymerase chain reaction (PCR) methods. Results showed an increase in pH from 6.71 to 6.97 with MPN index per 100 mL reduction of presumptive coliforms from >1,100 to 313.3 after digestion at 95% confidence interval (CI), respectively. A 3 log removal efficiency (99.9%) of Escherichia coli, Salmonella spp., Azomonas spp. and Aeromonas hydrophila was achieved after 30 days retention time in the bio-digester. The significant reduction of these surrogate pathogens during the process of biogas production is of importance to mitigate against environmental health concerns. Keywords—Anaerobic digestion, biogas, methanogens, pathogen reduction