What is Biofilm Treatment?
Aerobic biofilm treatment, also known as fixed-film process, is an engineered adaptation of natural soil purification. Alongside activated sludge processes, biofilm methods rank among the most widely applied aerobic biological treatments in wastewater management.
Key Features:
- Microorganisms attach and proliferate on carrier media under oxygenated conditions, forming a biofilm.
- Oxygenated wastewater flows through the media, where biofilm microbes degrade organic pollutants, purifying the water while thickening the biofilm.
- As biofilm thickens, oxygen diffusion limits create aerobic surface layers and anoxic/anaerobic inner layers, eventually causing biofilm sloughing. New biofilm then regenerates cyclically.
How Does Biofilm Treatment Purify Wastewater?
1. Adsorption & Degradation:
- A thin water layer forms on the biofilm surface, with organics pre-degraded to lower concentrations than influent.
- As wastewater flows past, organics transfer from bulk fluid to this boundary layer and are adsorbed by the biofilm.
- Oxygen diffuses from air into the biofilm, enabling aerobic decomposition.
2. Metabolic Byproducts:
- Microbes metabolize organics, releasing CO₂ and other inorganics back into the water/air.
- Result: Reduced organic content in effluent.
Advantages of Biofilm vs. Activated Sludge
