WesTech granular activated carbon (GAC) contactors are an effective means for removal of various-molecular-weight contaminants from aqueous solutions. They are especially suited for the removal of dissolved organic compounds responsible for poor taste and odor in drinking water, as well as removal of chlorine from industrial waters.
WesTech GAC contactors can be supplied in an open-top gravity system or, more commonly, in pressure vessels. They are typically designed with a conical underdrain for convenient GAC replacement. These filters are sized according to the contact time required for contaminant removal and desired media replacement frequency. Filter piping and valving for multiple units can be arranged to easily change flow paths between parallel flow, series (lead/lag or daisy chain) flow, or single-unit flow patterns.
Filters are typically backwashed only once upon new media installation, and the media usage front is then monitored via sample taps to allow for anticipation of media replacement.
WesTech pressure filtration systems are designed for both municipal and industrial water treatment where the removal of suspended solids such as particulates, iron, manganese, free oils, mill scale, and other precipitates in ground or surface water is required. Pressure filters are commonly placed after WesTech clarification equipment. When used as pretreatment equipment, these filters will prolong the life and efficiency of WesTech granular activated carbon, ion exchange, and membrane systems.
WesTech pressure vessels are available in a variety of configurations and designs that can be customized to meet various constraints such as water quality, footprint, backwash requirements and flow requirements. Customers have the option of either vertical pressure filters or horizontal (single or multi-cell) pressure filters. Vessels are designed at various pressure capacities. They are commonly constructed of painted carbon steel but can also be constructed of other corrosion-resistant materials.
A variety of underdrain options are available, including (but not limited to) false bottom, header-and lateral, and arched plate. Several overdrain options are also available, including (but not limited to) splash-plate, header-and lateral, single point (i.e. upturned elbow), multi-point (i.e. 4-point "H" style, etc.), orificed pipe, and baffled (for combined air/water backwash).
Media options and arrangements are several and depend on the application and internal piping arrangement but often consist of a dual-media, sand-and-anthracite arrangement (to minimize backwash frequency) above a gravel support bed.