title: Enhancing post anaerobic digestion of full-scale anaerobically digested sludge using free nitrous acid treatment.
abstract: In some wastewater treatment plants (WWTPs), the ever increasing production of sludge with the expanding population overloaded the anaerobic digestion which compromises the sludge reduction efficiency. Post anaerobic digestion of anaerobically digested sludge (ADS) has been applied to enhance sludge reduction, however, to a very limited extent. This study verified the effectiveness of free nitrous acid (FNA i.e. HNO2) pre-treatment on enhancing full-scale ADS degradation in post anaerobic digestion. The ADS collected from a full-scale WWTP was subject to FNA treatment at concentrations of 0.77, 1.54, 2.31, 3.08, and 3.85 mg N/L for 24 h followed by biochemical methane potential tests. The FNA treatment at all concentrations resulted in an increase (from 1.5-3.1 % compared to the control) in sludge reduction with the highest improvement achieved at 0.77 mg HNO2-N/L. The FNA treatment at this concentration also resulted in the highest increase in methane production (40 %) compared to the control. The economic analysis indicates that FNA treatment is economically attractive for enhancing post anaerobic digestion of full-scale ADS.
authors: Advanced Water Management Centre (AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia.
authors: Tingting
authors: T
authors: Zhang
authors: Advanced Water Management Centre (AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia. q.wang@awmc.uq.edu.au.
authors: Qilin
authors: Q
authors: Wang
authors: Advanced Water Management Centre (AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia.|School of Chemical Engineering, The University of Queensland, Brisbane, QLD, 4072, Australia.
authors: Liu
authors: L
authors: Ye
authors: Advanced Water Management Centre (AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia. zhiguo@awmc.uq.edu.au.
authors: Zhiguo
authors: Z
authors: Yuan
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D008697:Methane / Q000737:chemistry; D009608:Nitrous Acid / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology
chemical_list: D008697:Methane; D009608:Nitrous Acid; D012722:Sewage; D062065:Wastewater
keywords: Anaerobically digested sludge; Free nitrous acid; Methane production; Post anaerobic digestion; Sludge reduction