UBC Theses and Dissertations
Renewable energy extraction from organic winery wastes through anaerobic treatment. Garcia Batres, José Ciro
The wine industry produces large amounts of liquid and solid organic wastes in the form of lees and pomace. The high concentration of organics, measured as chemical oxygen demand (COD) contained in these wastes complicates disposal or reuse, however, this same characteristic makes them ideal for anaerobic conversion to methane gas, a cleaner energy source than fossil fuels. The main objective of this research was to determine whether these wastes could be treated anaerobically to produce methane, and to isolate ideal conditions for conversion. Research activities included 1) a waste audit of a medium-sized winery to determine the type and quantities of organic waste produced, 2) characterization of the waste, 3) enrichment of anaerobic cultures, 4) a set of biochemical methane potential (BMP) tests to assess the impact of different waste combinations on methane yields, and 5) a second set of BMP tests to assess the impact on methane yields by different waste types at different food to microorganism ratios (F/M) and at different waste combinations. The research yielded the following general results. 1) Two anaerobic cultures were successfully enriched to degrade lees and tartaric acid. 2) BMP testing showed the enriched cultures could be overwhelmed by an excess of lees, and pomace could be degraded to some extent (~ 30% COD) but over long periods of time (> 100 days). Both wastes were successfully converted to methane but at different rates. Post-experiment analysis showed an F/M ratio of 5 might be ideal for methane conversion. 3) Another set of BMP tests revealed lees was converted to methane more efficiently at an F/M ratio of 4, yielding 0.25 ± 0.01 L CH4/g COD consumed. An ideal F/M ratio was not identified for pomace. Co-treatment of lees and pomace at different combinations did not reveal an ideal mix as all three combinations tested were statistically similar in yields, an average of 0.13 ± 0.02 L CH4/g COD consumed. It was found that pomace had inhibited methanogenesis in the co-treatment tests; however, further research is needed to determine the cause and extent of this inhibition.
Item Citations and Data
Attribution-NonCommercial-NoDerivatives 4.0 International