*Editorial* **Special Issue on Promising Research and Strategies in Wastewater Treatment, Sludge Management, and Valorisation: Volume I**

**Amanda Laca \* and Yolanda Patiño \***

Department of Chemical and Environmental Engineering, University of Oviedo, C/Julián Clavería s/n, 33006 Oviedo, Spain

**\*** Correspondence: lacaamanda@uniovi.es (A.L.); patinoyolanda@uniovi.es (Y.P.)
