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In the corn-ethanol production plant, ethanol is distilled and whole stillage, which is the residue of enzymatic hydrolysate of corn fermentation mixture, is usually centrifuged to produce a liquid fraction (thin stillage) and a solids fraction (wet distillers’ grains). Processing of thin stillage with conventional methods (evaporation and drying) in corn-ethanol plants is energy intensive. Therefore, alternative approaches such as anaerobic digestion can be applied to improve the energy balance of the process since the biogas produced from the digesters presents an alternate energy source. The primary objective of this work is to optimize the bioconversion of organic compounds present in thin stillage to biogas using an Anaerobic Baffled Reactor (ABR) through innovation in feeding strategies and granular sludge formation. The reactor is capable of handling a high Total Suspended Solid (TSS) concentration, which appears to be the case for thin stillage. The vertical baffles in the reactor lead to the separation of acidogenic and methanogenic bacteria, resulting in an enhanced process control and robustness to load fluctuations. Additionally, upward flow movement and the presence of baffles enhance the sludge retention and, as a result, favor sludge granulation. In this work, a 30 liter anaerobic baffled reactor is used for the treatment of thin stillage with Chemical Oxygen Demand (COD) of 111 g/L and TSS of 24 g/L. For this purpose, the effect of various operational parameters such as organic loading rate and hydraulic retention time on COD removal, biogas production and methane yield is explored.
Thin stillage, Anaerobic baffled reactor, Biogas production, Watewater treatment
. 2016. Anaerobic Digestion of Thin Stillage in an Anaerobic Baffled Reactor for the Waste Management of Bioethanol Industries. CSBE/SCGAB 2016 Annual Conference, Halifax, 3-6 July 2016.
CSBE/SCGAB 2016 Annual Conference, Halifax, 3-6 July 2016.
Session 4A: Bioenergy Conversion Technologies II
Canadian Society for Bioengineering