We’re no longer allowed to put food scraps in our black bins. That’s because an EU directive dictates that food waste can no longer go to landfill. Methane, the gas produced from rotting organic matter, is so bad for the environment, it’s ten times more pollutant than CO2.
Households have their brown bins. But large food producers – restaurants, hotels and hospitals – go to great expense to have food waste removed. And, they can generate a tonne of food waste every day.
In fact, 41% of the waste from your local restaurant, pub or hotel, on average, is food waste – and a total of 3.4 m tonnes of food is disposed of by the food sector overall, each year.
But with the right technology, all of that organic matter can be converted into energy, which can be converted into revenue.
Entrepreneur Stephen Beck of Zero Waste Biotech has been working on a machine that ties all this together in one very special box.
TechWatch: What’s the main function of your aerobic digester?
Stephen Beck: “We design and build bespoke aerobic digesters that can convert food and organic waste into a high energy fuel source. This can displace fossil fuel.
“Right now there’s a waste problem. We’re changing that to zero waste energy solution.”
TW: How big is it?
SB: “They start from the size of a washing machine.”
TW: How long does food waste take to convert to fuel?
SB: “Our aerobic digester only takes 24 hours – that’s what makes it unique. The secret in it is how the different bacteria are mixed to achieve the 24 hour cycle.”
TW: How long do other digesters take?
SB: “A normal composter takes six months, and a normal anaerobic digester takes four weeks to produce brown gas. They generate a sludge matter that can leak.
“Ours generates fuel in a solid powder format that is less messy with less risk of contamination. It’s been pasteurised; an inert material.”
TW: What is the machine made of?
SB: “It’s a stainless steel and plastic drum – a typical one could be two metres by one metre – and they churn the waste with the bacteria mix.
“It’s-all natural bacteria that we’ve developed, which is activated at different times in the cycle. The bacteria are self-populating.”
TW: Has it been tested?
SB: “We’ve been testing them for a couple of years now. The digester has tested very well, but the touchpoints between ourselves and the customers needed working out. We interact with the customer when we collect the fuel, and we can top up the bacteria if that’s needed.”
TW: How does that work?
SB: “At the end of the digestion cycle, the fuel goes into a hopper and a sensor informs us when to come collect it.”
TW: So you have two revenue streams, from the fuel and the machines?
SB: “That’s right. The customers pay a monthly fee and that includes the machine and removal of the fuel. The biomass fuel is taken away and we can sell that to energy producers.”
TW: Who benefits – apart from the environment?
SB: “The customer could save 30-40% of the cost of removing waste straight away.
“We’re also looking at a combined waste and heat solution. We’re looking for the first site – so we could use the fuel on-site to power a hospital, for instance.”
Zero Waste Biotech is a finalist in the 2018 Invent competition in the Engineering category.
