Waste valorization, a pivotal concept to circular economy, can be combined with advanced wastewater treatment, thus offering sustainable solutions. In this respect, red mud (from bauxite processing), steel slag, and agro-industrial biochars serve as catalysts/activators to induce low-cost Fenton and alike reactions based on sources of radicals such as hydrogen peroxide and persulfate salts.

The proposed systems are tested for the degradation of emerging micro-contaminants with respect to the effect of catalyst pre-conditioning to process performance; special attention is also given to the role of the water matrix and possible interferences amongst water constituents, catalysts, oxidants and the target compound.