Biofilm development in fixed bed biofilm reactors: experiments and simple models for engineering design purposes

Area of Science:

• Environmental Engineering
• Microbiology
• Chemical Engineering

Background:

• Biofilm development is crucial for wastewater treatment efficiency.
• Fixed bed biofilm reactors (FBBRs) are widely used in municipal wastewater treatment.
• Accurate biofilm mass data is essential for optimizing reactor design and performance.

Purpose of the Study:

• To monitor biofilm development and mass accumulation in an FBBR system.
• To collect data for engineering practice in process design.
• To evaluate biofilm growth parameters for both steady-state and dynamic models.

Main Methods:

• Conducted a 6-month experimental study on FBBRs for municipal wastewater treatment.
• Monitored biofilm formation and reactor performance.
• Analyzed data using steady-state (maximum biofilm mass vs. influent load, time constant) and dynamic (attachment-detachment model) approaches.

Main Results:

• Maximum biofilm mass was determinable with reasonable error, ranging from 438 to 843 gTS/m(2) carrier surface.
• The time constant of biofilm growth could not be reliably determined simultaneously with maximum biofilm mass.
• The attachment rate coefficient was determined, ranging from 0.05-0.4 m d(-1), influenced by influent load and hydrodynamics.

Conclusions:

• The study successfully quantified maximum biofilm mass and attachment rates in FBBRs.
• Simultaneous determination of biofilm growth time constant and maximum mass was not feasible with the collected data.
• Findings provide valuable data for engineering design of wastewater treatment processes using FBBRs.