title: Applying real-time control for achieving nitrogen removal via nitrite in a lab-scale CAST system.
abstract: In this study, a bench-scale Cyclic Activated Sludge Technology (CAST) reactor (72?L), fed with domestic sewage, was operated in alternating anoxi-aerobic operation mode to investigate the feasibility of achieving short-cut nitrification and denitrification with a real-time control strategy. An online system for controlling the length of the aeration and stirring phases was implemented, based on pH and oxidation-reduction potential signals, to switch between aerobic and anoxic sequences. Results show that the real-time control strategy was successful in achieving a stable nitrogen removal performance. Furthermore, short-cut nitrification can be achieved by controlling aeration length under the modified real-time control strategy. Gradually reducing the energy supply for nitrite-oxidizing bacteria caused the limitation of their growth and, finally, their elimination. When short-cut nitrification was obtained, the nitrite pathway became the primary way for nitrogen removal, and aeration duration was reduced by 28.4%.
authors.affiliation: Department of Envionmental and Municipal Engineering, Tianjin Institute of Urban Construction, Tianjin 300384, China. wspfr@sina.com.cn
authors.forename: Shaopo
authors.initials: S
authors.lastname: Wang
authors.forename: Jingjie
authors.initials: J
authors.lastname: Yu
authors.forename: Tianlan
authors.initials: T
authors.lastname: Wei
authors.forename: Yongzhi
authors.initials: Y
authors.lastname: Chi
authors.forename: Liping
authors.initials: L
authors.lastname: Sun
authors.forename: Yongzhen
authors.initials: Y
authors.lastname: Peng
mesh_terms: D019149:Bioreactors; D005240:Feasibility Studies; D009573:Nitrites / Q000302:isolation & purification*; D009584:Nitrogen / Q000302:isolation & purification*; D012722:Sewage / Q000737:chemistry; D018508:Water Purification
chemical_list: D009573:Nitrites; D012722:Sewage; D009584:Nitrogen