title: Temperature modeling in activated sludge systems: a case study.
abstract: A model of temperature dynamics was developed as part of a general model of activated-sludge reactors. Transport of heat was described by the one-dimensional, advection-dispersion equation, with a source term based on a theoretical heat balance over the reactor. The model was compared to several reference models, including a tanks-in-series model and the dispersion model with heat components neglecting biochemical-energy inputs and other activated-sludge, heat-balance terms. All the models were tested under steady-state and dynamic conditions at a full-scale facility, the Rock Creek wastewater treatment plant in Hillsboro, Oregon, using meteorological data from a station located 16 km from the plant. The dispersion model and tanks-in-series model matched in situ temperature data with absolute-mean errors less than 0.1 degrees C. Neglecting biochemical-heat-energy inputs in the activated-sludge reactor underestimated temperatures by up to 0.5 degrees C. The biochemical-heat-energy inputs accounted for 30 to 40% of the total heat flux throughout the year.
authors.affiliation: Gdansk University of Technology, Department of Civil and Environmental Engineering, Gdansk, Poland. jmakinia@pg.gda.pl
authors.forename: Jacek
authors.initials: J
authors.lastname: Makinia
authors.forename: Scott A
authors.initials: SA
authors.lastname: Wells
authors.forename: Piotr
authors.initials: P
authors.lastname: Zima
mesh_terms: D019149:Bioreactors; D004777:Environment; D008962:Models, Theoretical; D012722:Sewage / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors
chemical_list: D012722:Sewage