Heterotopic formaldehyde biodegradation through UV/H2O2 system with biosynthetic H2O2

Biodegradation was regarded an environmentally benign and cost-effective technology for formaldehyde (CH,O) removal. However, the biotoxicity of CH2O inhibited microbial activity and decreased removal performance. We developed a novel heterotopic CH2O biodegradation process that combined bioelectrochemical system (BES) and UV/H2O2. Instead of exogenous addition, H2O2 was biosynthesized with electron transferred from electrochemically active bacteria. Heterotopic biodegradation of CH2O 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 H2O2 concentration of 102 mg/L, and pH 3, heterotopic biodegradation removed 78%, 73%, 49%, and 30% of CH2O with 6, 8, 10, and 20 mg/L initial concentration. Mild formation of hydroxyl radicals from UV/H2O2 is beneficial to sustainable CH2O degradation and efficient H2O2 utilization. Heterotopic biodegradation is a promising technology for efficient degradation of other organic compounds with biological toxicity. (C) 2019 Water Environment Federation