Turning garbage into gas

Innovative Danish bio-science – and one forward-looking city council – turning household rubbish into biofuel and new business

The Jutland city of Fredericia has joined up with the Dong Energy company to be the launch community for a new, environmentally-friendly waste management system that turns household rubbish and wastewater into biofuel.

Through the new partnership, Fredericia Council will be the first community in the nation to turn its waste into a storable and portable biofuel that can eventually be used to run city busses and generators and provide heat for homes.

“Our goal is to change the management of wastewater and household rubbish from a costly problem into a valuable resource for local energy production,” Fredericia’s mayor Thomas Banke told Jyllands-Posten newspaper. “Rubbish will be turned into gas, which will be sold and become an asset for the council’s budget.”

The venture is based on a new bio-refining process called REnescience developed by Dong Energy with researchers from Danish universities, the Amagerforbrænding waste incineration facility, and the biotech company Novozymes, among others.

Household rubbish and wastewater are spun and heated up to temperatures of 80-90 degrees Celsius in a cylindrical drum; enzymes that digest the organic components are added and after 15-20 hours a brown burnable biofuel is left over. According to the Ministry of Foreign Affairs, the non-organic waste – plastics, metals and glass, for example – that are not digested by the enzymes can then be separated from the biofuel, allowing for further recycling.

At Amagerforbrænding, where the technique underwent testing, approximately 800 kilos of waste per hour were treated and turned into biogas using existing equipment. Future REnescience plants will be able to process ten times as much waste and may also be able to convert the waste into ethanol and methanol, in addition to biogas.

Today Fredericia Council is already creating 1.2 million cubic meters of biogas through an older refining technique. But through the new REnescience enzyme-based process, the city’s biogas output is expected to double.

Preben Birr-Pedersen, the project leader for the new public-private collaboration between Fredericia and Dong Energy told Jyllands-Posten “the gains are going to be huge environmentally.”

“As soon as September, we will be the first in Denmark to put biogas back into the natural gas network where it can be saved up and used when it is most needed,” Birr-Pedersen said. “When it comes to the transportation sector, it’s going to be worth a lot. We expect that the added biogas production, which can be turned into combustable fuel, will increasingly be a green alternative and could even replace diesel.”

Mayor Banke says that while the environment is the biggest winner, Fredericia’s residents will also profit through lower waste management bills and potential jobs.

“One of the consequences, in the long run, will probably be lower prices for waste management. It’s cheaper, in any case, than garbage incineration,” Banke said, adding that “the really big winner is the environment and future Danish workplaces. We cannot count on having the same workplaces we have today in ten years. We therefore have to think new and innovate.”

Banke added that he hoped Fredericia would inspire other cities to adopt the new technology and make biofuel and jobs of their own.

“We can only encourage other councils to go the same way,” he said. “It’s important for the environment and it’s important for maintaining our standard of living.”