Two-Step Anaerobic Fermentation for Hydrogen and Methane Production from Cassava Wastewater Using Upflow Anaerobic Sludge Blanket Reactors

  • Ms Patcharaporn Chaimongkol, The Petroleum and Petrochemical College, Chulalongkorn University, Thailand
  • A/Prof Sumaeth Chavadej, The Petroleum and Petrochemical College/Center for Petroleum, Petrochemicals, and Advanced Materials, Chulalongkorn University, Thailand
  • Assit Prof Thammanoon Sreethawong, The Petroleum and Petrochemical College/Center for Petroleum, Petrochemicals, and Advanced Materials, Chulalongkorn University, Thailand
  • Asso Prof Pramoch Rangsunvigit, The Petroleum and Petrochemical College/Center for Petroleum, Petrochemicals, and Advanced Materials, Chulalongkorn University, Thailand

    • The aim of this study was to produce both hydrogen and methane from cassava wastewater using two sequential steps of upflow anaerobic sludge blanket reactors (UASB) with mixed culture. Each UASB unit had a liquid holding volume of 24 L and was operated at a constant temperature of 37 degree centigrade. The organic concentration of the studied cassava wastewater, in terms of chemical oxygen demand (COD), was in the range of 19,000 to 22,000 mg/L. For the hydrogen production step, hydrogen was produced using heat-shocked sludge, and the UASB system was operated at a constant pH of 5.5 by recycling the effluent and at different COD loading rates. A maximum specific hydrogen production rate of 0.39 L/Ld and a maximum hydrogen yield of 39.83 L/kg COD removed were found at a COD loading rate of 25 kg/m3d. For the methane production step, the studied UASB was fed by the effluent produced from the hydrogen production step at a COD loading rate of 25 kg/m3d. The system was operated at a constant temperature of 37 degree centigrade without pH control and at different COD loading rates in order to obtain the optimum conditions for maximum methane production efficiency.