A biofilter model called 'BIOFILT' was used to simulate the removal of biodegradable organic matter (BOM) in full-scale biofilters subjected to a wide range of operating conditions. Parameters that were varied included BOM composition, water temperature (3.0-22.5°C), and biomass removal during backwashing (0-100%). Results from biofilter simulations suggest a strong dependence of BOM removal on BOM composition. BOM with a greater diffusivity or with faster degradation kinetics was removed to a greater extent and also contributed to shorter biofilter start-up times. In addition, in simulations involving mixtures of BOM (i.e. readily degradable and slowly degradable components), the presence of readily degradable substrate significantly enhanced the removal of slowly degradable material primarily due to the ability to maintain greater biomass levels in the biofilters. Declines in pseudo-steady state BOM removal were observed as temperature was decreased from 22.5 to 3°C and the magnitude of the change was significantly affected by BOM composition. However, significant removals of BOM are possible at low temperatures (3-6°C). Concerning the impact of backwashing on biofilter performance, BOM removal was not affected by backwash resulting in biomass removals of 60% or less. This suggests that periodic backwashing should not significantly impact biofilter performance as observed biomass removals from full-scale biofilters were negligible. In general, the simulation results were in good qualitative and quantitative agreement with experimental results obtained from full-scale biofilters. Copyright (C) 2000 Elsevier Science Ltd.
Bibliographical noteFunding Information:
The authors acknowledge the financial support provided by the American Water Works Association (AWWA) through the Abel Wolman Doctoral Fellowship Program and by the AWWA Research Foundation through Project 252. The authors also acknowledge the advice and input of fellow team members on AWWARF Project 252 including Peter Huck, Brad Coffey, Appiah Amirtharajah, Monica Emelko, and Daniel Urfer.
- Biodegradable organic matter
- Simulation model