title: Modeling the pH effects on nitrogen removal in the anammox-enriched granular sludge.
abstract: The aim of the study was to determine the pH effects on nitrogen removal in the anammox-enriched granular sludge. The experimental data were extracted from a 4 L completely-mixed batch reactor with the granular sludge at different initial pH values (6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5) and constant temperature T = 30 °C. Simulations were run in GPS-X 6.4 using a comprehensive mechanistic model Mantis2. Two kinetic parameters, the maximum specific growth rates of ammonia oxidizing bacteria (AOB) and anammox bacteria, were optimized at different pH scenarios. The inhibitory effects of the pH extremes on the anammox-enriched sludge were discussed in terms of the inhibition of free nitrous acid and free ammonia and metabolic mechanisms. Two different pH functions were used to examine the pH effects on the nitrogen removal kinetics. The pH optima for AOB and anammox bacteria were 7.4 and 7.6, respectively. The maximum specific growth rates of AOB and anammox bacteria at the pH optima were 0.81-0.85 d-1and 0.36-0.38 d-1(at T = 30 °C). The measured specific anammox activities (SAAs), predicted SAAs by Mantis2 and fitted SAAs by the Michaelis pH function at the pH optima were 0.895, 0.858 and 0.831 gN/(gVSS·d), respectively (VSS: volatile suspended solids).
authors.affiliation: Institute of Environmental Science and Engineering, Tongji University, Shanghai 200092, China E-mail: luxi953@foxmail.com.
authors.forename: Xi
authors.initials: X
authors.lastname: Lu
authors.affiliation: Institute of Environmental Science and Engineering, Tongji University, Shanghai 200092, China E-mail: luxi953@foxmail.com.
authors.forename: Zhixuan
authors.initials: Z
authors.lastname: Yin
authors.affiliation: Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Gdansk 80-233, Poland.
authors.forename: Dominika
authors.initials: D
authors.lastname: Sobotka
authors.affiliation: Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Gdansk 80-233, Poland.
authors.forename: Kamil
authors.initials: K
authors.lastname: Wisniewski
authors.affiliation: Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Gdansk 80-233, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Czerwionka
authors.affiliation: Institute of Environmental Science and Engineering, Tongji University, Shanghai 200092, China E-mail: luxi953@foxmail.com.
authors.forename: Li
authors.initials: L
authors.lastname: Xie
authors.affiliation: Institute of Environmental Science and Engineering, Tongji University, Shanghai 200092, China E-mail: luxi953@foxmail.com.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Gdansk 80-233, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Makinia
mesh_terms: D000641:Ammonia; D000693:Anaerobiosis; D019149:Bioreactors; D058440:Denitrification; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D009584:Nitrogen / Q000378:metabolism*; D010084:Oxidation-Reduction; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D012722:Sewage; D014874:Water Pollutants, Chemical; D000641:Ammonia; D009584:Nitrogen