At the WWTP of Linz-Unkel (Germany), ELIQUO has constructed a unique decentralised sludge processing plant. The design, is based on the PYREG® technology, where the sludge is converted into a valuable phosphate rich ash. Currently these ashes are utilised in Germany at part of the production of various fertiliser products.

The Linz-Unkel WWTP is treating the sewage from 30.000 inhabitants. Sludge from WWTP Linz-Unkel and sludge from neighbouring WWTP’s is digested.  The digested sludge  is dewatered and dried using an ELODRY® low temperature dryer. This sludge dryer has been developed in-house based on market leading technology  and is produced at the own ELIQUO factories. After drying the sludge to approx. 90% ds, the PYREG®  module converts it into a phosphate rich ash utilising a patented two-stage combustion process. The heat which is recovered from the PYREG® system is used together with the waste heat from the works CHP system to provide all the necessary thermal energy for the ELODRY® process. To further optimize the process waste heat which is recovered from the ELODRY® process is utilised for heating the WWTP’s digesters.

This unique and integrated ELODRY®-PRO concept converts a waste product into valuable phosphate rich ash by utilising the benefits of an entirely closed heat loop. As all of the digested sludge is converted to a valuable ash there is no remaining sludge for disposal and therefore transport and disposal costs are reduced to zero.