More methane from Biogas by breaking ‘Fatbergs’

FOG is a terrific source of organic material that microorganisms can feed on to produce methane gas, which is a valuable, renewable energy source. But if it’s too rich in organics, bacteria can’t handle it and the process breaks down. By preheating it to the right temperature, we ensure that the FOG is ready for the final treatment and can make the maximum amount of methane,” says research associate Asha Srinivasan.

Ultimately, the technology can be used in municipal FOG management programs, says lead researcher Victor Lo, emeritus professor of civil engineering at UBC. “The principle would be the same: you could pretreat the FOG so it doesn’t clog the pipes, and add it to sewage sludge to produce methane from the mix,” said Lo. 

Clogging of sewage through fat, oil and grease was a major problem in London, which will be solved through the research. Earlier also many treatments were available for the disposition of these waste but have not been associated with more methane production. The research will enhance the production of methane from biogas plants. These substances get deposited in the form of fat and harm aquatic ecosystem. They take the form of ‘Fatbergs’ which are really harmful and needs to be dissolved for disposal. 

He added that the methods developed at UBC will enable farmers to load more FOG into their biogas digesters—the large tanks that treat farm wastes, including cow manure, to produce methane. “Farmers typically restrict FOG to less than 30 per cent of the overall feed. But now the FOG can be broken down into simpler forms, so you can use much more than that, up to 75 per cent of the overall feed. You would recycle more oil waste and produce more methane at the same time.” 

This research will find ways for the enhancement of farmer’s income through more amount of production of methane from biogas if treated in biogas plants. Researchers heated FOG samples to temperatures between 90 and 110 degrees Celsius and added hydrogen peroxide, a chemical that kick starts the breakdown of organic matter. Researchers said the treatment dramatically reduced the volume of solids in the FOG by as much as 80 per cent. It also released fatty acids from the mixture that can be broken down by bacteria in the next stage of treatment. 

Lo said “To the best of our knowledge, this type of pretreatment for FOG has not been studied before, although simple chemical methods do exist to break down FOG”. “We’re hoping to do more research to find the optimal ratio of FOG to dairy manure so that they can be pretreated together.”