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Magnetite Ballasted Biological System – BioMag (Retrofit Existing or New)

Evoqua BioMag – Ballasted biological process to allow WWTP to handle 3x flow and solids loadings, and to operate at longer sludge ages to achieve enhanced nutrient removal, without physically adding tankage to the plant.

Magnetite is a dense, non-abrasive, iron oxide mined locally in Missouri  that can be recovered magnetically from the waste activated sludge and reused in the process to maintain an extremely dense, fast settling biomass. Results in a plant with small footprint, low capital, and low operational costs.

Easy to incorporate in any type of activated sludge treatment where biological process remains unchanged and BioMag equipment is located in the sidestream location (WAS stream) without impacting main liquid stream in the WWTP.  Ability to with multi-stage treatment processes, to meet TN to ≤ 3.0 mg/L and TP to ≤ 0.2 mg/L without tertiary filters

The enhanced settling capabilities of the BioMag System has been proven at municipal and industrial facilities to deliver the following results:

  • BOD5 < 5.0 mg/L
  • TSS < 10 mg/LEvoquaBioMagLogo_000
  • NH3-N < 0.2 mg/L
  • TP < 0.2 mg/L without filters
  • TN < 3.0 mg/L without filters
  • SVI < 70 mL/gram
  • Clarifier SLR up to 100 lb/day-ft2
  • Clarifier SOR up to 2,500 gpd/ft2
  • MLSS up to 10,000 mg/L
  • MLVSS up to 8,000 mg/



  • Simplicity and reliability – Ballasting biological floc with magnetite dramatically increases secondary settling rates eliminating bottlenecks to process greater loads, flows or both.
  • Up to triple the capacity – Rapid and reliable settling enables a 2 – 3x increase in MLSS concentrations without the risk of upset, and an equivalent increase in treatment capacity — all within existing bioreactors and clarifiers.
  • Low-cost ENR – Increased capacity and superior solids removal enable existing activated sludge systems to free up reactor capacity for multi-stage treatment processes, thereby enabling the removal of TN to ≤ 3.0 mg/L and TP to ≤ 0.2 mg/L without tertiary filters.
  • Lower life-cycle costs – The BioMag™ System continuously recovers and reuses up to 95% of the injected magnetite offering a cost-effective, sustainable process.
  • Dedication and experience—Evoqua has 40 years of experience in biological processes, offering a holistic view when upgrading a plant, and maximizing synergies between BioMag and secondary treatment equipment.