Phototheque VEOLIA - Stephane Lavoue

Co-digestion of organic waste produces energy

Posted on 22 March 2016.

Sewage sludge + organic waste = green energy. It’s a promising equation that Veolia has successfully put in place in seven wastewater treatment plants in Hungary.

When digested along with other organic waste, sewage sludge has enormous potential as a renewable energy resource.

Waste water treatment plants produce residues made up of organic and inorganic materials. This is sewage sludge, and it is now becoming a major issue for the environment.

Reducing it, is the real problem, it is usually spread on the land or incinerated. But there is another, better solution: use it to produce green energy!

The principle is simple: the sludge is mixed with organic waste and then put into digesters. During the digestion process, the mixture produces "biogas", a substance composed mainly of methane and carbon dioxide, which when burned is an excellent fuel. In short, when digested along with other waste, the sludge from waste water treatment plants has enormous potential as a renewable energy resource.

Although the solution has been considered by a number of industries, many have hit a major obstacle: recovering the organic waste. How can organic waste (leftovers from our plates, out of date food, food industry rejects, etc.) be separated from non-biodegradable waste (plastic bags, heavy metals, pollutants, etc.)?

Which is where Veolia comes in having innovated with its "Ecrusor" technology - a system that simultaneously shreds and separates organic waste and non-biodegradable waste.

The system was introduced in 2004 in Hungary’s wastewater treatment plant in Budapest. The organic waste recovered by Ecrusor is mixed with sewage sludge, with which mixture can be produced during co-digestion 2 or 3 time more biogas a day than before - enough fuel for the  waste water treatment plants to be energy self-sufficient!

Ecrusor is blazing the trail for tomorrow's industries. Industries that manage their waste better and produce their own energy... and why not in the future, enough for others too?