Napier Reid’s Granular Activated Carbon (GAC) filtration systems remove the contaminants from the water through adsorption, in which negatively charged contaminant ions are attracted by the positively charged activated carbon. The organic compounds are removed by absorption, and residual disinfectants such as chlorine and chloramines are removed by catalytic reduction.

GAC is normally placed in a pressure vessel or gravity filtration tank through which raw water passes. The carbon filters mechanically strain out dirt, sediment, algae, bacteria, microscopic worms, cryptosporidium, and asbestos.  When the surface area of the carbon granules is clogged with the contaminants due to adsorption, pressure differential increases and the filter bed is backwashed.

Napier-Reid uses different type of GAC, bituminous,lignite, wood, or coconut shell, depending on the type of contaminants being targeted.

Napier-Reid uses different types of GAC, bituminous, lignite, wood, or coconut shell, depending on the type of contaminants being targeted.



  • Best suited for removal of dissolved organic compounds responsible for taste and odour, suspended solids, and chlorine removal from industrial water.
  • Highly efficient feed water distribution system.
  • Efficient under-drain collection/distribution system for minimal pressure drop and proper backwashing.
  • High quality GAC media has a high surface area, high iodine value, low ash content, and low moisture in each system.
  • Very stable and reliable operation.
  • Custom designed and fabricated in order to suit the process and site requirements.
  • Smaller footprint compared to other systems.
  • N-R GAC systems increase the life and efficiency of ion exchange and RO system when used for previous pretreatment.
  • PLC / SCADA control package available for automatic control of the process.
  • Optimum design and size keeping in view all operating conditions, resulting in lower capital cost, years of smooth operation and considerable savings for the client
  • N-R GAC system can be supplied as a complete package, assembled, tested, inspected and with complete piping.
  • Carbon steel tower or pressure vessel, interior epoxy lined suitable for potable service and prime exterior finished.
  • Fiberglass reinforced polyester (FRP) pressure vessels available for 150 psig working pressure.


Optional Granular Activated Carbon filtration system can be a single treatment step or can be combined with other processes to remove free chlorine and dissolved organics from:

  • Municipal Water
  • Municipal Wastewater
  • Surface Water
  • Ground Water
  • Industrial Wastewater


GAC odour control systems also available for wastewater applications.