title: Towards energy positive wastewater treatment by sludge treatment using free nitrous acid.
abstract: Free nitrous acid (FNA i.e. HNO2) was revealed to be effective in enhancing biodegradability of secondary sludge. Also, nitrite-oxidizing bacteria were found to be more susceptible to FNA than ammonium-oxidizing bacteria. Based on these findings, a novel FNA-based sludge treatment technology is proposed to enhance energy recovery from wastewater/sludge. Energy analysis indicated that the FNA-based technology would make wastewater treatment become an energy generating process (yielding energy at 4 kWh/PE/y; kWh/PE/y: kilowatt hours per population equivalent per year), rather than being a large energy consumer that it is today (consuming energy at 24 kWh/PE/y). Importantly, FNA required for the sludge treatment could be produced as a by-product of wastewater treatment. This proposed FNA-based technology is economically and environmentally attractive, and can be easily implemented in any wastewater treatment plants. It only involves the installation of a simple sludge mixing tank. This article presents the concept of the FNA-based technology.
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, QLD 4072, Australia.
authors.forename: Qilin
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Key Laboratory of Urban Stormwater System and Water Environment/R&D Centre for Sustainable Wastewater Treatment (Beijing University of Civil Engineering and Architecture), Ministry of Education, Beijing 100044, PR China.
authors.forename: Xiaodi
authors.initials: X
authors.lastname: Hao
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, QLD 4072, Australia. Electronic address: zhiguo@awmc.uq.edu.au.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Yuan
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000378:metabolism; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D004736:Energy-Generating Resources; D009573:Nitrites / Q000302:isolation & purification / Q000378:metabolism; D009608:Nitrous Acid / Q000494:pharmacology*; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D009573:Nitrites; D009608:Nitrous Acid; D012722:Sewage; D062065:Wastewater
keywords: Energy recovery; Free nitrous acid; Methane; Nitrite pathway; Sludge treatment