aul Brackley writes in the Cambridge Independent about the Algal Innovation Centre at Cambridge University’s Botanic Garden. Built at a cost of £500,000 by the University, including £188,600 from a European Union project to research alternatives to fossil fuels, the center opened at the Botanic Garden last year and is designed to take lab research to an industrial scale.
“It looks like a normal greenhouse but there are a few hidden features in here – like a sealed floor so that if there are any spills we can contain them. We have ‘swimming pools’ here where we can do scale-up experiments up to 1,000 litres,” says Dr. Matt Davey, a senior research associate at the Department of Plant Sciences.
“Cambridge Water has lots of nitrate waste to deal with,” says Dr. Davey. “We wondered whether we could take the waste and produce artificial algal blooms. It’s what we call a bio-circular economy – we take waste from one industry source, grow the algae and then do something with it such as produce methane for electricity or heat production rather than putting the nitrates back into the water supply.”
The methane production is carried out using anaerobic digestion – the same process already in use at plants around the country. “You concentrate it down into a paste and then digest the algal cells, rotting them using enzymes, and that produces the methane. The trials carried out here show that per kilogram of algae it produces more methane compared to common agricultural leaf matter used in anaerobic digestion plants,” he says.
“We know it performs better and the feedback from anaerobic digestion companies is even if they had it as a blend of five or 10 per cent that’s better than nothing, if you are getting the algae growing on another industry’s waste source.”
Growing sufficient quantities of algae – particularly with high oil content to create more methane – is the remaining challenge to make the process commercially viable, meaning it could still be some years before the process becomes established industrially.
Air lift reactors are used at the Algal Innovation Centre to bubble air through the algae, turning it as it moves. But in addition to light for photosynthesis algae need nutrients – nitrates, along with phosphates, potassium and more – and some species need a vitamin B12 boost.
Understanding how different strains of algae thrive in different climates could have a significant industrial benefit – and enable algae to be grown more widely. “We can have year-round production – in summer you grow one species and in winter you grow another,” says Dr. Davey.