Influence of vitamin coupled with micronutrient supplement on the biomethane production, process stability, and performance of mesophilic anaerobic digestion

Abstract

Batch anaerobic digestion (AD) using municipal solid waste (MSW) as a substrate with anaerobic sludge as inoculum were carried out under mesophilic conditions to understand the effect of Vitamin supplement coupled with micronutrients on the AD process. Reactions were operated using various concentrations of vitamin and water-based metal supplementations. The stability and process performance in the low level supplementation was indicated by evaluating Volatile fatty acids to alkalinity ratio, pH as well as methane kinetics. The feasibility of AD process was further evaluated by cost-benefit ratio analysis. This study shows that Vitamin addition as a sole supplement had either no significant or negative effect on methane production and process performance of anaerobic digestion (AD). However, coupling the metal supplement with vitamins shows an increase in methane production up to 30% compared to sole vitamin supplement and control systems. This study also shows that high levels of metal supplementation were detrimental and 15% decline in methane production over the control system was observed in high concentrations. Low level addition improved the reactor performance and process stability. Moreover, cost/benefit ratios lower than 1 were achieved for these concentrations. Hence, low levels of vitamin and water-based metal supplementation at 0.5–5 mg/L, increased the methane production and process stability by approximately 15, and 25% respectively.