title: A model to control intermittent aeration phases.
abstract: Dealing with intermittent aeration as a useful practice to improve nitrogen removal efficiency of activated sludge plants, the possibility to plan optimal temporisation during daytime was investigated. A mathematical model (NIDEN) that allows us to manage different situations, with respect to influent load, environmental conditions and operating strategy, was then developed. The model represents a useful tool especially to plan the aeration cycles in small and medium sized plants, where high costs of automatic control through on-line instrumentation might not be justified. Once the input variables have been defined and the set-point values for tank nutrient concentration have been fixed, NIDEN gives an optimal phase temporisation, to obtain either the maximum energy saving or the best total nitrogen removal.
mesh_terms: D001331:Automation; D003247:Conservation of Natural Resources; D004736:Energy-Generating Resources; D005160:Facility Design and Construction; D008962:Models, Theoretical; D009584:Nitrogen / Q000302:isolation & purification*; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D012722:Sewage; D009584:Nitrogen