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Sergio Pino-Jelcic
Senior Technical Sales Manager

The CoMag® System for Enhanced Primary or Tertiary Treatment

Dramatically increases capacity performance and helps meet tightening regulations

The CoMag®​ system uses magnetite fully inert iron ore particles to enhance the clarification process. The system settles chemical floc up to 30 times faster than conventional treatments, enabling plants to increase capacity and enhance clarifier performance.  

Additionally, the CoMag system can reduce plant investment costs by limiting clarification tank size. It can achieve total phosphorus down to 0.05 mg/L and can achieve UV transmittance  greater than 75% when integrated into any type of coagulation/flocculation process or clarifier. The CoMag system also is the only ballasting technology with an internal recycle from clarifier underflow to process tanks, which reduces chemical consumption. Magnetite ballast, which is added into the chemical reactor to accelerate settling, is continusly separated from the clarifier underflow stream. Typically, 99 percent of the magnetite is recovered and reused in the system.  

Learn more about the CoMag system's latest installation in Alderson, W.Va., by reading the news release​. You can also learn how the CoMag System ​met stringent phosphorus limits within extremely tight footprint constraints.

Also, read this article​ to find out why Severn Trent is using the CoMag system to remove phosphorous at its Finham Sewage Treatment Works in the UK.



The CoMag System competes effectively with all forms of media and membrane filtration and conventional clarification, and is proven effective for:

Municipal applications:

  • Primary treatment (chemically enhanced primary treatment)
  • Tertiary treatment for polishing secondary effluent
  • Stormwater/CSO (combined sewer overflow)
  • SSO (sanitary sewer overflow)
  • Wet weather control​
  • Recycle-reuse applications
  • Reverse osmosis pretreatment
  • Drinking water
  • Heavy metals removal
  • Lagoon/reservoir for high solids, algae, and phosphorus
  • Fixed film application (right after fixed-film bioreactor)
  • Temporary treatment during or before plant upgrade projects

Industrial applications:

  • Food and beverage
  • Oil and gas
  • Industrial make-up process water


  • Easy to incorporate into any type of coagulation/flocculation process
  • Can use with any type of clarifier (circular, rectangular, squircle, inclined plate/tube settlers)
  • Only ballasting technology with an internal recycle from clarifier underflow to process tanks that reduces chemical consumption
  • Recycling promotes sludge densification and solids contact for better flocculation and sweeping effect in clarifiers to enhance capture of colloidal particles.
  • Magnetite is dense (2X more dense than silica sand), readily available (iron ore commodity), fully inert (NSF certified for DW applications)​, not abrasive (particle size is 40-50 microns) and magnetically retrievable (high recovery rates.)
  • Package plug and play offering for up to 300,000 gpd
  • Easy to pilot—Evoqua has two pilot units available and has conducted 35-40 pilots.
  • Rapid startup and quick process optimization for operation with frequent shut-down and re-starts
  • Fully automated


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

  • SOR up to 15 gpm/ft2 with conventional
  • SOR up to 50 gpm/ft2 with plate settlers
  • Turbidity < 1 NTU
  • TP < 0.05 mg/L
  • TSS < 2.0 mg/L 
  • Color 2 Pt-Co Units
  • Fecal Coliform < 200 Col/100 mL
  • Copper < 8 μg/L
  • Aluminum < 80 μg/L
  • Arsenic < 5 μg/L
  • UV Transmittance > 75%
  • Oil and Grease Removal

 Extends Equipment Service Life

​The CoMag system's magnetite ballast extends equipment service life. This impeller pump has been operating operating continuously with the CoMag system for more than a decade without any signs of abrasion.

 Video: CoMag® System for Enhanced Primary and Tertiary Treatment

 Video: CoMag® System Jar Test Demonstration

 key benefits

Superior contaminant removal - Efficiently reduces total suspended solids (TSS), total phosphorus (TP), turbidity, color, pathogens, and metals far below conventional treatment, without the need for filters

Low costs - High-rate, ballasted clarification allows for smaller reaction and solids separation tanks, minimal power consumption and moderate chemical use

Easy incorporation – CoMag is easy to incorporate into existing tankage

Lower OPEX - Continuously recovers and reuses up to 99+% of the injected magnetite, offering a sustainable process for lower OPEX

Process stability – Stability under shock loads – does not choke or plug; rapid startup and quick process optimization

Ultraviolet enabling - The high transmissivity of the CoMag System effluent reduces energy and operating costs of final purification

User friendly - Fully automated, requires minimum operator attention, easy to operate, core equipment has been used by industry for decades

Plug and play - Package plug and play offering for up to 300,000 gpd

Click on the tiles below for more information on Evoqua's innovative ballasted treatment solutions. The CoMag® System for Enhanced Primary or Tertiary Treatment