**Preface to "Advanced Technology of Waste Treatment"**

The protection of human health and the environment as well as the sustainable use of natural resources requires the chemical, biological, and physical treatment of waste. This refers to the conditioning (e.g., drying, washing, comminution, rotting, stabilization, neutralization, agglomeration, homogenization), conversion (e.g., incineration, pyrolysis, gasification, dissolution, evaporation), and separation (classification, direct and indirect (i.e., sensor-based) sorting) of all kinds of wastes following waste hierarchy principles (i.e., prevention (not addressed by this issue), preparation for re-use, recycling, other recovery and landfilling). Longstanding challenges include the increase in the yield and purity of recyclable fractions and the removal or destruction of pollutants from the circular economy.

> **Daniel Vollprecht and Renato Sarc** *Editors*
