title: Deammonification for digester supernatant pretreated with thermal hydrolysis: overcoming inhibition through process optimization.
abstract: The thermal hydrolysis process (THP) has been proven to be an excellent pretreatment step for an anaerobic digester (AD), increasing biogas yield and decreasing sludge disposal. The goal of this work was to optimize deammonification for efficient nitrogen removal despite the inhibition effects caused by the organics present in the THP-AD sludge filtrate (digestate). Two sequencing batch reactors were studied treating conventional digestate and THP-AD digestate, respectively. Improved process control based on higher dissolved oxygen set-point (1 mg O2/L) and longer aeration times could achieve successful treatment of THP-AD digestate. This increased set-point could overcome the inhibition effect on aerobic ammonium-oxidizing bacteria (AerAOB), potentially caused by particulate and colloidal organics. Moreover, based on the mass balance, anoxic ammonium-oxidizing bacteria (AnAOB) contribution to the total nitrogen removal decreased from 97 ± 1 % for conventional to 72 ± 5 % for THP-AD digestate treatment, but remained stable by selective AnAOB retention using a vibrating screen. Overall, similar total nitrogen removal rates of 520 ± 28 mg N/L/day at a loading rate of 600 mg N/L/day were achieved in the THP-AD reactor compared to the conventional digestate treatment operating at low dissolved oxygen (DO) (0.38 ± 0.10 mg O2/L).
authors.affiliation: DC Water, 5000 Overlook Ave. SW, Washington, DC, 20032, USA.|Laboratory of Microbial Ecology and Technology (LabMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Gent, Belgium.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: DC Water, 5000 Overlook Ave. SW, Washington, DC, 20032, USA.
authors.forename: Haydée
authors.initials: H
authors.lastname: De Clippeleir
authors.affiliation: DC Water, 5000 Overlook Ave. SW, Washington, DC, 20032, USA.
authors.forename: Chunyang
authors.initials: C
authors.lastname: Su
authors.affiliation: DC Water, 5000 Overlook Ave. SW, Washington, DC, 20032, USA.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Al-Omari
authors.affiliation: ARAconsult, Unterbergerstr.1, 6020, Innsbruck, Austria.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Wett
authors.affiliation: Laboratory of Microbial Ecology and Technology (LabMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Gent, Belgium. siegfried.vlaeminck@uantwerpen.be.|Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerpen, Belgium. siegfried.vlaeminck@uantwerpen.be.
authors.forename: Siegfried E
authors.initials: SE
authors.lastname: Vlaeminck
authors.affiliation: DC Water, 5000 Overlook Ave. SW, Washington, DC, 20032, USA.
authors.forename: Sudhir
authors.initials: S
authors.lastname: Murthy
mesh_terms: D064751:Ammonium Compounds; D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism*; D019149:Bioreactors; D058440:Denitrification; D006868:Hydrolysis; D010100:Oxygen; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater
chemical_list: D064751:Ammonium Compounds; D010100:Oxygen; D012722:Sewage; D062065:Wastewater
keywords: Biological nitrogen removal; Denitrification; Partial nitritation/anammox; Reject water