Journal of Fundamentals of Renewable Energy and Applications
Open Access

Abstract

Anaerobic Co-Digestion of Wastewater Activated Sludge and Rice Straw in Batch and Semi Continuous Modes

Nabil N Atta, Amro A El-Baz, Noha Said and Mahmoud M Abdel Daiem

digestion of sewage sludge with rice straw may be attractive option from energetic, as well as, environmental viewpoints. In this study, co-digestion of wastewater activated sludge (WWAS) with grinded rice straw at different ratios (0.5, 1.0, 1.5 and 3.0%), straw to WWAS based on weight, was performed using batch reactors. Moreover, a semicontinuous model was developed for sludge digestion and co-digestion with rice straw. The results showed that the co-digestion of WWAS with rice straw improved the carbon to nitrogen ratio (C/N) and consequently increased biogas production compared to sludge digestion. Moreover, total solids, total volatile solids and chemical oxygen demand were reduced by digestion during the reaction time. Furthermore, the biogas yield increased by increasing mixing ratio in co-digester and reached four times at maxing ratio 3.0% compared to sludge digestion. The semi-continuous model showed that the co-digestion increased total biogas amount continuously and methane was the main component in biogas released from digester and co-digester.