Inhibition Effects of Zinc and Copper on Volatile Fatty Acid Production During Anaerobic Digestion

Abstract The inhibition of copper and zinc ions on the acidogenesis phase in anaerobic treatment was studied. Glucose acclimated anaerobic bacterial sludge was used in the inhbition experiments. Metals were introduced as shock doses to batch reactors. Inhibition of bacterial activity was quantified by individual volatile fatty acid measurements. For both metals, production activity of propionic acid was the most severely affected, with acetic acid being the next. Copper was more toxic to the bacterial culture. Mixtures of the two metal ions exhibited a clear antagonistic behaviour on inhibition of volatile acid production. Keywords: Zinccopperinhibitionacidogenesisanaerobic digestionvolatile fatty acids