Modeling of Temperature Impacts on Fixed Film Microbial Growth and Nitrification Kinetics

Abstract

Monod-type kinetic models, used in simulating microbial growth in biological treatment systems, suggest significant decreases of substrate utilization at lower temperatures. However, it is documented that performance of fixed film treatment systems are not hindered with declining temperatures. Studies at the Moorhead, MN, Wastewater Treatment Facility (WWTF) showed significant impacts of temperature on biofilm growth in its moving bed biofilm reactor (MBBR) and noted that more biomass was present at low temperatures. A series of kinetic bench-scale batch tests was performed to measure ammonium removal in the full-scale system. As part of this research, a diffusion based kinetic model was developed to simulate the bench-scale trials and determine if Monod kinetics and temperature corrections properly model fixed film systems. It was found that Monod kinetics and temperature corrections do apply to fixed film system as long as proper consideration is given to the change in biofilm characteristics.

Mass Transfer Characteristics of Floating Media in MBBR and IFAS Fixed-Film Systems

“…There is much evidence in the literature that media-related biomass increases at low temperatures (Shrestha et al, 2009;Wett et al, 2010;Sticker et al, 2009;Bjornberg et al, 2009;Hoang et al, 2014;Strombeck et al, 2014). The Bjornberg (2009) paper provides a detailed summary of biomass fluctuations throughout the year at a plant in Minnesota.…”