The startup Cleef System has industrialized the recovery of sewage sludge as fuel according to a principle that resembles the production of churros.
The technology consists of frying sewage sludge in oil or grease waste in order to produce combustible pellets with a very high calorific value. As such, it allows to co-valorise two waste products by producing a biofuel with a favorable carbon footprint. After a few years of R & D a first installation is now operational on the industrial site of Roussillon in Isère (France).
