Heterotopic formaldehyde biodegradation through UV/H 2 O 2 system with biosynthetic H 2 O 2

Biodegradation was regarded an environmentally benign and cost‐effective technology for formaldehyde ( CH 2 O) removal. However, the biotoxicity of CH 2 O inhibited microbial activity and decreased removal performance. We developed a novel heterotopic CH 2 O biodegradation process that combined bioelectrochemical system ( BES ) and UV /H 2 O 2 . Instead of exogenous addition, H 2 O 2 was biosynthesized with electron transferred from electrochemically active bacteria. Heterotopic biodegradation of CH 2 O was more efficient and faster than in situ biodegradation, as confirmed by 69%–308% higher removal efficiency and 98% shorter degradation time. Operated under optimal conditions for 30 min, which are optical distance of 2 cm, initial H 2 O 2 concentration of 102 mg/L, and pH 3, heterotopic biodegradation removed 78%, 73%, 49%, and 30% of CH 2 O with 6, 8, 10, and 20 mg/L initial concentration. Mild formation of hydroxyl radicals from UV /H 2 O 2 is beneficial to sustainable CH 2 O degradation and efficient H 2 O 2 utilization. Heterotopic biodegradation is a promising technology for efficient degradation of other organic compounds with biological toxicity. Practitioner points H 2 O 2 biosynthesis through electrochemically active bacteria (EAB) served as source of · OH for CH 2 O removal in UV /H 2 O 2 . Heterotopic CH 2 O biodegradation avoided the biotoxicity of CH 2 O. Heterotopic biodegradation of CH 2 O saved 98% time than in‐situ biodegradation. Heterotopic CH 2 O biodegradation improved 69%–308% efficiency than in‐situ.