The fourth deals with the recovery and re-use of waste from tannery processes through the purification and re-use of wastewater, and the extraction of useful substances.
Neljanda projektiga käsitletakse parkimisprotsesside jäätmete uuesti kasutusele võtmist reovee puhastamise ja taaskasutamise ning kasulike ainete eraldamise teel.