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
