Rotating Biological Contactors (RBC)
Energy-efficient fixed-film biological treatment with rotating media for reliable wastewater purification
Overview
What is Rotating Biological Contactors (RBC)?
Rotating Biological Contactor (RBC) technology represents a proven, energy-efficient approach to biological wastewater treatment. The system consists of large diameter media discs mounted on a horizontal shaft that rotates slowly, alternately exposing the biofilm-covered surfaces to wastewater and atmospheric oxygen. This simple yet effective design provides consistent treatment performance with minimal energy input and operational complexity.
As the media rotates, microorganisms attached to the disc surfaces absorb organic matter and nutrients from the wastewater during the submerged phase. During the aerial phase, the biofilm is exposed to oxygen, enabling aerobic degradation of absorbed pollutants. Excess biomass naturally sloughs off into the wastewater and is removed in downstream clarification.
Spans Envirotech's RBC systems feature high-density polyethylene media optimized for biofilm attachment, corrosion-resistant drive assemblies, and protective enclosures. Our designs are ideal for small to medium-scale applications requiring reliable treatment with minimal energy consumption and maintenance requirements.
Process
RBC Treatment Process
Media Rotation
Disc media mounted on a central shaft rotates at 1-2 RPM, powered by electric motors or in some cases, natural flow. Approximately 40% of media surface remains submerged.
Biofilm Development
Microorganisms colonize media surfaces, forming a dense biofilm. The rotating action prevents excessive biomass accumulation and maintains active, healthy biofilm.
Pollutant Absorption
During the submerged phase, biofilm absorbs organic matter, nutrients, and contaminants from wastewater through direct contact and mass transfer.
Aerobic Oxidation
During the aerial phase, absorbed oxygen enables microorganisms to oxidize pollutants, converting organic matter to CO2, water, and biomass.
Biomass Removal
Shear forces from rotation and media submergence cause excess biofilm to slough off. Sloughed solids settle in downstream clarifiers for removal.
Benefits
Key Advantages
- Extremely low energy consumption - up to 80% less than activated sludge
- Simple mechanical design with minimal moving parts reduces maintenance
- Excellent process stability resistant to shock loads and toxic compounds
- Produces well-stabilized sludge with lower quantities than suspended growth systems
- No clogging issues associated with submerged media systems
- Effective nitrification capability with appropriate staging
- Suitable for remote locations with limited operational expertise
Applications
Industries & Use Cases
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