Activated Carbon Water Contactor

GAC Polishing Across Water Treatment

The SorbiTech Activated Carbon Water Contactor is the workhorse vessel for liquid phase adsorption duties. The pressure vessel or gravity basin holds a fixed bed of SorbiTech GAC 1240 or a specialty grade matched to the target contaminant; treated water passes downward through the bed at a face velocity that gives the contracted empty bed contact time. Outlet concentration meets the regulator limit on chlorine, taste and odour compounds, dissolved organic carbon, trihalomethane precursors, or the emerging contaminants list (PFAS, pharmaceutical residue, pesticide).

EBCT Sizing and Bed Depth

Empty bed contact time (EBCT = bed volume / volumetric flow) is the master sizing parameter:

• Dechlorination: EBCT 2 to 6 minutes
• Taste and odour (geosmin, MIB): EBCT 8 to 15 minutes
• Dissolved organic carbon and THM precursors: EBCT 15 to 25 minutes
• PFAS short and medium chain: EBCT 10 to 20 minutes

Bed depth follows from the face velocity (8 to 15 m/h service, 25 to 40 m/h backwash) and the EBCT. A deeper bed at the same EBCT gives a longer service life because the mass transfer zone is a smaller fraction of the bed volume.

Scope of Supply and Configurations

Engineered by SorbiTech in pressure vessel (ASME VIII) or gravity basin (concrete or epoxy lined steel) configuration. Standard scope includes wedge wire underdrain, inlet diffuser, outlet collector, NSF/ANSI 61 wetted materials, backwash valves and flow meter, sampling ports at multiple bed depths, and PLC control. The SorbiTech GAC charge is loaded under controlled conditions and conditioned before service.

Reactivation Programme

When the carbon is spent it is removed and thermally reactivated at the SorbiTech partner facility; the reactivated carbon is returned to service at 85 to 95 percent of virgin activity. The reactivation contract lowers the lifecycle cost by 40 to 60 percent compared with single use operation. SorbiTech maintains the spent carbon collection schedule aligned to the operator backwash cycle.

Sector Coverage

Applications include drinking water polishing, industrial process water, food and beverage process polishing, and groundwater remediation. Sectors span municipal water treatment, industrial water treatment, and food and beverage.