Gore Hill, Montana - Arsenic and Iron Removal

In November 2009, AdEdge Water Technologies was contacted by Great West Engineering to provide an arsenic and iron removal system for the Gore Hill County Water Treatment Plant Wells #1 and #2 in Great Falls, Montana. The existing water system consisted of multiple wells feeding into a centralized distribution system with a maximum capacity of 150 gallons per minute (gpm).

The raw water for Gore Hill Plant #1 has an average arsenic level of 18 parts per billion (ppb) and an iron level of 1.39 mg/L, well above the U.S. EPA maximum contaminant levels (MCLs) of 10 ppb and 0.3 mg/L, respectively. Gore Hill Plant #2 has an average arsenic level of 21 ppb and an average iron level of 4.51 mg/L, also well above the MCLs of 10 ppb and 0.3 mg/L.

Each AdEdge treatment system features a skid-mounted AD26 oxidation and filtration package unit sized for a maximum design flow of 150 gallons per minute (gpm). Gore Hill Plant #1 features the model APU26-4260CS-2-AVH and utilizes AdEdge AD26 media in a two-vessel configuration. Gore Hill Plant #2 features the model APU26-4260CS-3-AVH and utilizes AdEdge AD26 media in a three-vessel configuration.

Each system is equipped with automated control valves and harness, central control panel with programmable logic controller (PLC) and a color user interface screen. System features also include differential pressure switches, control panel and local gauges, flow sensors and totalizers, and a central hydraulic panel with sample ports for a complete functioning packaged unit. A continuous feed of sodium hypochlorite is fed prior to the treatment system to optimize the removal of arsenic and iron. Each 42-inch diameter treatment vessel contains 28 cubic feet of AdEdge AD26 oxidation/filtration media.

In addition to the arsenic and iron treatment systems, AdEdge provided a recycle backwash system for each site. The backwash recycle system reclaims 100% of the backwash waste water and removes the captured arsenic and iron as a semi-solid sludge that can be disposed of in a non-hazardous landfill. Backwashing of the treatment systems occurs two or three times a week, depending on the incoming levels of iron and water usage.

The system started up and commenced in April 2011. Since the system began operation, iron levels are at non-detectable levels and arsenic levels have lowered from 18 ppb and 21 ppb to non-detectable levels.

Case Study Fast Facts

Client: Gore Hill County Water Treatment Plant
Facility: Wells #1 and #2
Engineer: Great West Engineering
Location: Great Falls, MT
Date: April 2011
Contaminant: Arsenic/Iron
Flow Rate: 150 gpm