Moving Bed Biofilm Process in Activated Sludge Model 1 for Reject Water Treatment

Abstract

A moving bed biofilm (MBB) process was modelled in AQUASIM using the standard activated sludge model 1 (ASM1) as a baseline. The model was controlled against experimental data from a pilot Hybrid Vertical Anaerobic Biofilm (HyVAB) reactor installed at Knarrdalstrand wastewater treatment plant, Porsgrunn, Norway. High ammonium concentration removal from reject water was studied by applying different aeration schemes at the plant and the modelling tool. Results show that the standard ASM1 model was poor to fit experimental data. Simulation results evidenced missing biochemical mechanisms related to anaerobic ammonium oxidation (Anammox) and short cut nitrogen removal processes. However, the essential simulation outputs are biofilm thickness, substrates concentration variation, and biomass distribution, partially validated with experimental results. The model, therefore, helped to realise the nature of the bioprocess observed at the pilot reactor.