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Mark Pamperin
Product Manager - Biological Processes

VertiCel® Secondary Treatment System for Biological Nutrient Removal

Aeration with a smaller footprint and less energy
The VertiCel®​ process is a series of VLR® contact tanks followed by fine-bubble diffuser reactor tanks. This suspended growth activated sludge process is designed to minimize energy consumption and accomplish Biological Nutrient Removal (BNR). The process uses two types of aeration devices to optimize aeration efficiency. Power costs of the VertiCel process are 20 to 30% lower than competitors. It uses deep rectangular reactors for reduced space requirements and can be retrofitted into existing rectangular aeration basins.



  • Simultaneous nitrification - denitrification
  • Typical Flow > 5 MGD (> 18,900 m3/d)
  • Stormwater treatment
  • Retrofit of existing fine bubble aeration plants


  • Prevents short-circuiting of ammonia through the system
  • Achieves higher kinetic reaction rate so basin volume can be reduced
  • Can maintain different environments in each reactor for nitrogen and phosphorus removal.
  • Deep tank design reduces the footprint, thereby reducing construction and maintenance costs
  • Common wall construction
  • Hybrid energy efficient biological wastewater treatment: Utilizes both disc aeration and find bubbles diffusers
  • Reactors operate in series
  • Stormflow mode of operation prevents Biosolids washouts to clarifiers

 key benefits

  • Operation flexibility—The VertiCel System's series of reactors promotes nitrification through alternate pathways at near zero dissolved oxygen levels.
  • Low energy costs—The VertiCel System combines mechanical aeration in the aerated/anoxic zones with diffused aeration in the aerobic zones to optimize the process aeration efficiency. The VertiCel System design consumes an average of 30% less power when compared with fine bubble aeration systems.
  • Unique disc aeration – Envirex® Disc Aerators provide superior mixing and aeration while efficiently transferring oxygen to minimize power costs.
  • Flexibile aeration – Changes in oxygen demand can be met by varying disc rotational speed and/or air flow in the aeration tanks.
  • Effectively manages peak flows – Surge flows are managed within the VertiCel System without solids washout. No auxiliary peak flow facilities are needed and a more economical final clarifier design can be employed.
  • High quality components – Drives, bearings, and shafting are all oversized and constructed in a rugged fashion to extend the life of the equipment while reducing maintenance requirements.
  • Performance – Reduces effluent levels to non-detectable VertiCel® Secondary Treatment System for Biological Nutrient Removal