In this era of changing climate and the need for a more renewable energy resource, sources of biogas alternatives have been of popular demand. Put simply, biogas is the result of anaerobic digestion (breakdown of organic material in the absence of oxygen) of biodegradable materials. The primary byproduct of this digestion process is methane, which can ultimately be used as a biofuel in motor vehicles or other machines that historically have used petroleum-based gas.
The organic source material for biogas production has most often been manure (which is in ample supply), though can also come from human sewage, municipal waste, plant material, and crops. These sources alone, while they are great sources of methane for biofuel, are somewhat inefficient in the anaerobic digestion process. Studies have shown that co-digestion, the anaerobic digestion of a mixture of at least two different organic substrates, increases anaerobic digestion efficiency by balancing the carbon:nitrogen ratio, macro/micro nutrients, pH, and toxic compounds. Co-digestion of at least two organic substrates also have high-buffering capacity, which would be more difficult to obtain if anaerobically digested alone.
“Wait a minute; this is a blog about science related to wine. Where do you come off talking about cow pies and biofuels?”
The wine industry generates typically very large quantities of wastewater, which comes from washing procedures after the crushing and pressing of grapes, rinsing of the fermentation tanks, barrels, and other equipment used in the winery. The resulting wastewater is typically acidic, has a high organic load, and high polyphenol, macro/micro nutrient, and heavy metal concentrations. It is possible that the levels of these compounds may vary, depending upon local laws, though for the purpose of this article, we’ll assume there are no differences in wastewater content between wine regions (this article focus on the wine industry in Spain).
It has been suggested that the wastewater from the wine industry could act as the second organic substrate of which to be anaerobically digested with manure to create biogas/biofuel. Very few studies have examined this pairing, therefore the overall objective of the article reviewed today aimed to determine if winery wastewater could co-digest with manure (of the swine variety) to create a potential new source of a renewable biofuel.
Methods (well, a couple sentence sum-up of a rather complex system):
To put it very simply, the scientists of this study took varying levels of winery wastewater and combined it with varying levels of swine manure, and compared their methane (and other chemical attributes) production to using swine manure alone. The three treatment types were: 75% swine manure plus 25% winery wastewater; 60% swine manure plus 40% winery wastewater; and finally 90% swine manure plus 10% winery wastewater (all compared to 100% swine manure without any winery wastewater).
- The carbon:nitrogen ratio and the pH of the co-digestion of winery wastewater and swine manure showed that the pair would successfully improve the problems that normally occur when digesting manure alone (as discussed earlier).
- Methane content was above 68% for all treatments
- Co-digestion improved methane production in comparison with anaerobic digestion of swine manure alone.
- The highest biogas production was achieved the there was 25% winery wastewater added to the co-digestion mix (75% swine manure).
o The high methane potential achieved by the co-digestion of winery wastewater and swine manure may be the result of the high anaerobic biodegradability of the ethanol and sugars in the winery wastewater.
What is the significance of these results?
The results of this study indicate that the co-digestion of swine manure (and thereby theoretically other types of animal wastes) and winery wastewater is a promising potential source of biogas as an alternative renewable source of energy. As the percentage of winery wastewater in the co-digestion increased, the methane yield increased.
In a world where the need for alternative fuels is steadily growing, any potential options deserve serious consideration. Methane, a compound that is 21 times more potent than carbon dioxide in causing global warming, could be harnessed as a potential biofuel by creating a way to burn it instead of letting it escape into the atmosphere, which would ultimately help ameliorate some of the affects of global warming. By combining the seemingly unendless supply of animal manure around the globe with the vast quantities of winery wastewater, of which no end in supply is in sight, we may have a new alternative source of energy and biofuel that can be used in lieu of more harmful alternatives.
Not only is combining animal manure with winery wastewater more efficient in producing higher quantities of methane for the use of biofuels, but it also answers the question of the proper way to dispose of these potential toxins without harming the environment in which they are created.
I’d love to hear your comments on this topic! Please feel free to leave your thoughts below!
Source: doi: 10.1016/j.biortech.2010.12.077
I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!