title: Anaerobic digestion of glycerol and co-digestion of glycerol and pig manure.
abstract: The potential of glycerol obtained from transesterification of waste cooking oil as a main carbon source for biogas production was investigated. The glycerol was highly contaminated with oils and fats and was pretreated with sulfuric acid. Using a carbon source of glucose as a control, we compared biogas production from the acid-treated glycerol in a synthetic medium and the acid-treated glycerol mixed with pig manure. The anaerobic digestion of acid-treated glycerol with supplement in a synthetic medium was found to be satisfactory at organic loading rates (OLR) between 1.3, 1.6 and 2.6 g chemical oxygen demand (COD) L(-1) d(-1). The maximum methane yield of 0.32 L at Standard temperature and pressure (STP) g(-1) COD removal was achieved at an OLR of 1.6 g COD L(-1) d(-1) and the methane content was 54% on an average. At a higher organic loading rate of 5.4 g COD L(-1) d(-1), the propionic acid to acetic acid ratio was higher than the critical threshold limit for metabolic imbalance. Anaerobic digestion of acid-treated glycerol with pig manure was also investigated at the COD ratio of 80:20 (glycerol:pig manure). The anaerobic digestion of acid-treated glycerol with pig manure was found to be satisfactory at organic loading rates between 1.3, 1.7, 2.9 and 5.0 g COD L(-1) d(-1) in terms of COD reduction (>80%) and methane content of (62% on an average). However, the biogas production rate was found to significantly decrease at the highest load. The maximum methane yield of 0.24 L STP g(-1) COD removal was achieved at an OLR of 1.3 g COD L(-1) d(-1).
authors.affiliation: The Research and Technology Center for Renewable Products and Energy, King Mongkut's University of Technology North Bangkok, Bangkok, Thailand.
authors.forename: Sasikarn
authors.initials: S
authors.lastname: Nuchdang
authors.forename: Chantaraporn
authors.initials: C
authors.lastname: Phalakornkule
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D056804:Biofuels; D057919:Biological Oxygen Demand Analysis; D002244:Carbon; D005990:Glycerol / Q000378:metabolism*; D008372:Manure; D008697:Methane / Q000032:analysis / Q000378:metabolism; D009584:Nitrogen; D034421:Sus scrofa; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D056804:Biofuels; D008372:Manure; D002244:Carbon; D009584:Nitrogen; D008697:Methane; D005990:Glycerol