Heterotopic formaldehyde biodegradation through UV/H2 O2 system with biosynthetic H2 O2.

Biodegradation was regarded an environmentally benign and cost-effective technology for formaldehyde (CH2 O) removal. However, the biotoxicity of CH2 O inhibited microbial activity and decreased removal performance. We developed a novel heterotopic CH2 O biodegradation process that combined bioelectrochemical system (BES) and UV/H2 O2 . Instead of exogenous addition, H2 O2 was biosynthesized with electron transferred from electrochemically active bacteria. Heterotopic biodegradation of CH2 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 H2 O2 concentration of 102 mg/L, and pH 3, heterotopic biodegradation removed 78%, 73%, 49%, and 30% of CH2 O with 6, 8, 10, and 20 mg/L initial concentration. Mild formation of hydroxyl radicals from UV/H2 O2 is beneficial to sustainable CH2 O degradation and efficient H2 O2 utilization. Heterotopic biodegradation is a promising technology for efficient degradation of other organic compounds with biological toxicity. PRACTITIONER POINTS: H2 O2 biosynthesis through electrochemically active bacteria (EAB) served as source of ·OH for CH2 O removal in UV/H2 O2 . Heterotopic CH2 O biodegradation avoided the biotoxicity of CH2 O. Heterotopic biodegradation of CH2 O saved 98% time than in-situ biodegradation. Heterotopic CH2 O biodegradation improved 69%-308% efficiency than in-situ.