Process Improvement of Biogas Production from Anaerobic Co-digestion of Cow Dung and Corn Husk

A study of organic loading rate (OLR) and effect of NaOH concentration on the pretreatment stage of corn husk (CH) was conducted by Face-Centered Central Composite Design (CCF) to improve the biogas production. Three levels of OLR at 25.0 g VS · L−1 · d−1 (OLR25), 35.0 g VS · L−1 · d−1 (OLR35), and 45.0 g VS · L−1 · d−1 (OLR45) were performed with NaOH pretreatment concentration of CH at 25.0% (N25), 35.0% (N35), and 45.0% (N45) (w/w). The optimum production of biogas at 67.6 mL · min−1 with methane concentration of 63.4% has been obtained at the application of OLR at 43.6 g VS · L−1 · d−1 and NaOH concentration at 33% (w/w).