title: Combined free nitrous acid and hydrogen peroxide pre-treatment of waste activated sludge enhances methane production via organic molecule breakdown.
abstract: This study presents a novel pre-treatment strategy using combined free nitrous acid (FNA i.e. HNO2) and hydrogen peroxide (H2O2) to enhance methane production from WAS, with the mechanisms investigated bio-molecularly. WAS from a full-scale plant was treated with FNA alone (1.54 mg N/L), H2O2 alone (10-80 mg/g TS), and their combinations followed by biochemical methane potential tests. Combined FNA and H2O2 pre-treatment substantially enhanced methane potential of WAS by 59-83%, compared to 13-23% and 56% with H2O2 pre-treatment alone and FNA pre-treatment alone respectively. Model-based analysis indicated the increased methane potential was mainly associated with up to 163% increase in rapidly biodegradable fraction with combined pre-treatment. The molecular weight distribution and chemical structure analyses revealed the breakdown of soluble macromolecules with the combined pre-treatment caused by the deamination and oxidation of the typical functional groups in proteins, polysaccharides and phosphodiesters. These changes likely improved the biodegradability of WAS.
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, QLD 4072, Australia.
authors.forename: Tingting
authors.initials: T
authors.lastname: Zhang
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: Advanced Water Management Centre (AWMC), The University of Queensland, QLD 4072, Australia.|School of Chemical Engineering, The University of Queensland, QLD 4072, Australia.
authors.forename: Liu
authors.initials: L
authors.lastname: Ye
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, QLD 4072, Australia.
authors.forename: Damien
authors.initials: D
authors.lastname: Batstone
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, QLD 4072, Australia.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Yuan
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors; D006861:Hydrogen Peroxide / Q000737:chemistry*; D008697:Methane / Q000737:chemistry; D008962:Models, Theoretical; D009608:Nitrous Acid / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D018508:Water Purification / Q000379:methods
chemical_list: D012722:Sewage; D006861:Hydrogen Peroxide; D008697:Methane; D009608:Nitrous Acid