The emphasis on sustainability in recent years has placed an increased demand on environmentally friendly solutions that adhere to strict regulatory standards. The H2Zero™ backwash/recycle system from AdEdge Water Technologies conserves water by storing and treating contaminated backwash water from filtration and treatment systems. In 2009, AdEdge included an H2Zero™ backwash/recycle system in an arsenic and iron treatment system for the Gore Hill Water Treatment Plant #1 and Plant #2 in Great Falls, Montana. Some liquid or solid residuals are generated as a result of the oxidation/filtration treatment process which requires regular backwashing of the treatment system to remove suspended solids and iron particulates that accumulate in the media bed.
Backwash water from the treatment system for Plant #1 is stored in a 7,800 gallon holding tank and is blended with raw water at a rate of 10 percent the raw feed flow, resulting in a reuse of 100% of the water used for system backwashing. The backwash water from the treatment system for Plant #2 is stored in a 9,000 gallon holding tank and also has a reuse factor of 100% of the water used for system backwashing. Two wells feed a centralized distribution system with a maximum capacity of 150 gpm. The raw water for Plant #1 has an average arsenic level of 18 ppb and an iron level of 1.39 mg/L, well above the EPA MCLs of 10 ppb and 0.3 mg/L respectively. Plant #2 has an average arsenic level of 21 ppb and an average iron level of 4.51 mg/L, also well above the EPA MCLs of 10 ppb and 0.3 mg/L. The AdEdge arsenic and iron treatment system consists of two skid-mounted AD26 oxidation and filtration package units rated for a maximum design flow of 150 gpm.