Validating the colloid model to optimise the design and operation of both moving-bed biofilm reactor and integrated fixed-film activated sludge systems.
The paper presents a systematic study of simulations, using a previously calibrated Colloid model, from which it was found that: (i) for pure moving-bed biofilm reactor (MBBR) processes with tertiary nitrification conditions (no influent chemical oxygen demand (COD)), dissolved oxygen = 5 mg/L and residual NH4-N > 4 mgN/L, a nitrification rate of 1.2 gN/(m(2)d) was obtained at 10 °C. This rate decreases sharply when residual NH4-N is lower than 2 mgN/L, (ii) for MBBR systems with predenitrification-nitrification zones and COD in the influent (soluble and particulate), the nitrification rate (0.6 gN/(m(2)d)) is half of that in tertiary nitrification due to the effect of influent colloidal XS (particulate slowly biodegradable COD) and (iii) for integrated fixed-film activated sludge (IFAS) processes the nitrification rate in the biofilm (0.72 gN/(m(2)d)) is 20% higher than for the pure MBBR due to the lower effect of influent XS since it is adsorbed onto flocs. However, it is still 40% lower than the tertiary nitrification rate. In the IFAS, the fraction of the nitrification rate in suspension ranges from 10 to 70% when the aerobic solids retention time varies from 1.4 to 6 days.
Environmental Engineering Department, CEIT and Tecnun (University of Navarra), Manuel Lardizabal 15, 20018 San Sebastian, Spain E-mail: jon.albizuri@anoxkaldnes.com; AnoxKaldnes AB, Klosterängsvägen 11A, 22647 Lund, Sweden.
J
J
Albizuri
Environmental Engineering Department, CEIT and Tecnun (University of Navarra), Manuel Lardizabal 15, 20018 San Sebastian, Spain E-mail: jon.albizuri@anoxkaldnes.com.
P
P
Grau
AnoxKaldnes AB, Klosterängsvägen 11A, 22647 Lund, Sweden.
M
M
Christensson
Environmental Engineering Department, CEIT and Tecnun (University of Navarra), Manuel Lardizabal 15, 20018 San Sebastian, Spain E-mail: jon.albizuri@anoxkaldnes.com.
L
L
Larrea
D000332:Aerobiosis; D018441:Biofilms; D019149:Bioreactors; D003102:Colloids; D003198:Computer Simulation; D008954:Models, Biological; D058465:Nitrification; D018505:Waste Management
D003102:Colloids