They say one man’s trash is another man’s treasure but, when it comes to biogas, we could all be winners. Lizzie Anderson asks whether anaerobic digestion is the future of UK’s food waste problem?

It is a cool spring morning and 30 schoolchildren are enjoying a tour of the region’s first commercial food plant, Emerald Biogas, in Newton Aycliffe, County Durham. The youngsters, from nearby Woodham Burn Community Primary School, are among 200 children taking part in the company’s Eco Warriors campaign. They have been learning about food waste for weeks, as well as recycling their own leftovers in special bins. The visit is a chance to see how their discarded school dinners are being transformed into heat, power and fertiliser.

The curious youngsters are fascinated by the sights and sounds of the £8m factory and they are not the first.

When Janet Street-Porter attended the plant’s official launch in January, she was full of praise for the £8m facility.

The outspoken broadcaster, journalist, author and recycling campaigner, said: “This plant is using the stuff that gets thrown away and turning it into energy, which is great.

“The amount of food that ends up in the bin is phenomenal, and it’s not just homeowners either, it’s producers, supermarkets and hospitals.”

But is she right? What benefits has the plant brought to the region and could leftover lasagne and vegetable peelings really solve the UK’s green energy and waste management needs?

Biogas is created using anaerobic digestion, a complex process that takes place in the absence of air in a large sealed vessel with controlled heating and mixing. At Emerald Biogas, 100 tonnes of discarded food is taken each week from food manufacturers, retailers, restaurants and schools across the region. Clients include Marks and Spencer, Lidl, Greggs, SK Chilled Foods, Greencore and Primula

When the waste arrives, any remaining packaging is stripped away. Water is added to make it into a soup-like consistency, before the waste is pasteurised and transferred into a sealed building for processing. It is then pumped into a temperature-controlled sealed vessel known as a digester. It is here that bacteria feed on the food waste to produce biogas.

During the six-week process, no methane is released into the atmosphere. Instead, the methane and carbon dioxide are captured and turned into heat and electricity for the National Grid – enough to power 2,000 homes.

The remaining digestate is delivered to agricultural businesses within a 15-mile radius for use as a high nutrient bio-fertiliser.

Until County Durham food and recycling firm John Warren ABP and land management company Agricore opened Emerald Biogas last October, the North-East’s nearest commercial food plant was in Doncaster.

By building the plant, the company has saved 60,000 food waste miles a year.

And with a capacity to handle 50,000 tons of food waste a year, it is playing a big part in preventing the 80,000 tonnes created in the North-East being sent to landfill.

This begs the question, why has it taken so long for biogas to arrive in the region?

Mr Warren explains: “Seventeen years ago there was no tax on landfill and pretty much everything was thrown into holes in the ground. Tax was then introduced at a very low rate, around £2 per tonne, this crept up and now stands at around £80 per tonne. This is on top of the cost of transporting the waste.

“Environmental concerns also played a part. When waste breaks down gases and liquids are produced, which contaminate rivers and lakes.

“There are now very strict guidelines about what can be sent to landfill and people have started to look for alternatives.”

Mr Warren believes changing attitudes to waste and recycling at a domestic level have also helped pave the way for biogas plants, with eco-conscious consumers scrutinising the green credentials of their favourite retailers and expecting firms to adopt the same practises they adhere to at home.

“Waste was often seen as somebody else’s problem,” he says. “It would all be thrown into one bin and if someone else was willing to sort it out for recycling that was great but we were far too busy.

“These days, we have developed a conscience and we separate our plastic, glass and cardboard for recycling. Many of us have compost heaps too.”

With more and more schools and companies coming on board and planning permission already secured to extend the plant’s capacity, Emerald Biogas is likely to handle more and more of the region’s food waste.

Talks are underway to supply energy directly to other companies on the business park and plans for a new education centre will ensure even more children can understand the importance of responsible waste management.

Mr Warren adds: “It has always been part of our plan to teach children about what we do here. Children are the future and we believe biogas is the future.”