Principal component analysis and characterization of methane community in a full-scale bioenergy producing UASB reactor treating brewery wastewater

Abstract

The use of biogas from AD as renewable energy has been widely adopted by many industries worldwide to facilitate and lower the greenhouse effect through the reduction of methane emissions into the atmosphere. Removal of organic matter in brewery wastewater using AD system is important for eco-friendly environment and in the generation of renewable energy. This study investigated the efficiency of an up-flow anaerobic sludge blanket reactor (UASB) reactor in treating brewery wastewater and generation of biogas as one of the sources of renewable energy. Physico-chemical parameters, dynamics and abundance of methane-producing Archaea were studied using standard methods and fluorescent in-situ hybridization, respectively. Raw wastewater from brewery plant had high organic matter and solids content that needs pre-treatment before its discharged into the municipal wastewater treatment plants. The average removal efficiency recorded for biological and chemical oxygen demand were 60.21% and 78.97% respectively. The removal efficiency shows the performance of the investigated UASB reactor in reducing contaminants from brewery wastewater during anaerobic digestion. Methane producing Archaea was also active during the treatment process with biogas production containing 60–69% methane. The principal component analysis (PCA) showed the effect of pH and other measured physico-chemical parameters on methane production with high positive correlation coefficient (R > 0.6). The result of fluorescence in-situ hybridization analysis identified the methane-producing Archaea in the investigated UASB reactor treating brewery wastewater as orders Methanobacteriales, Methanococcales and Methanomicrobiales; genera Methanosaeta and Methanosarcina. The results of this study provide valuable reference information in optimizing and improving reactor performance for maximum bioenergy production through the degradation of organic matter present in brewery wastewater.