Enhancing the Biogas Production of Sludge Anaerobic Digestion by a Combination of Zero-Valent Iron Foil and Persulfate

Abstract

The excess amount of sewage sludge has been an enormous threat to environmental management. Anaerobic digestion is one of the effective ways to solve this intractable problem. However, the biogas production rate is not high enough because of the limitation of the hydrolysis stage. The potential of the zero-valent iron (ZVI)–persulfate oxidation method for enhancing the biogas production of sludge anaerobic digestion was investigated in this work. Meanwhile, a protocol of ZVI–persulfate oxidation experiments and anaerobic digestion batch tests was performed. The results indicated that the iron foil was promoted more than iron powder in ZVI–persulfate oxidation with the optimum dosage of 30 mmol/L ZVI and 30 mmol/L persulfate. The methane production increased by 53.6% at the optimum ZVI–persulfate dosage in comparison with the control set in the anaerobic digestion batch tests. The variation of volatile fatty acid concentration and composition during the anaerobic digestion were measured to prove the enhanc...