Instantaneous Joule Heating for Sustainable and Green Recycling of Sewage Sludge and Water Purification

Abstract Sewage sludge from wastewater treatment plants is increasing significantly, and its sustainable and green recycling remains a challenge. Herein, we develop a rapid Joule heating method for seconds upcycling sewage sludge into a reductive Fe/carbon composite. Reductive Fe produced by carbothermic reduction reactions effectively activated peroxydisulfate for producing SO4•– and •OH. Meanwhile, ultrahigh temperatures and electrostripping effects contributed to the formation of a graphene-like structure, which can strengthen organic pollutant adsorption and electron transfer during persulfate-based advanced oxidation processes for organic pollutant removal. Sludge-derived material possesses excellent degradation efficiency toward organic pollutants over a wide pH range and in common environmental anions, indicating great adaptability for practical wastewater treatment. Importantly, we developed a continuous Joule heating system using a Programmable Logic Controller with robotic arms for scale-up production from practical sludge. The results showed that the sludge-derived material has a great organic pollutant removal efficiency for industrial pharmaceutical wastewater, showing great application potential through the “treating waste with waste” route. Obviously, instantaneous Joule heating has been regarded as a next-generation promising candidate for sustainable and green recycling of sewage sludge and water purification.