Tertiary treatment of pulp mill wastewater by solar photo-Fenton

► We firstly report a real pulp mill wastewater treatment by solar photo-Fenton in a CPC reactor. Fenton reagent experiments were tested firstly. ► Solar photo-Fenton presents excellent ability to treat the pulp mill wastewater. ► Experimental conditions were optimised. ► Biodegradability and toxicity tests (respirometry assays and BOD5/COD ratio) were performed during the wastewater treatment. ► A way to reduce the economic and environmental impact was evaluated.