Oxidation/filtration system reduces contaminant levels for Boulder residences
In October 2010, AdEdge Water Technologies LLC was contacted by JVA Inc. to provide an iron and manganese  dewatering system for the 29th Street Residences located in Boulder, Colo. The raw groundwater contains iron levels between 4.6 and 7.4 mg/L and a manganese level of 4.5 mg/L, well above the U.S. Environmental Protection Agency (EPA) secondary maximum contaminant levels (MCLs) of 0.3 mg/L and 0.05 mg/L respectively. The iron and manganese levels need to comply with the EPA MCLs in order to be able to discharge into the sanitary sewer and meet applicable discharge criteria.
The AdEdge treatment system features a skid-mounted AD26 oxidation and filtration  package unit sized for a maximum design flow of 50 gal per minute (gpm). The model APU26-3060CS-4-AVH utilizes AdEdge AD26 media in a four-vessel carbon steel configuration in series. Each 30-in. diameter treatment vessel contains 13.5 cu ft of AdEdge AD26 manganese dioxide oxidation/filtration media. AdEdge AD26 media is a NSF 61-certified black filter media used for the removal of arsenic, iron and manganese.
The system is equipped with automated control valves and harness, a 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. An auto dialer was integrated into the treatment system for ease of operation. Prior to the AdEdge treatment system, AdEdge provided two supply pumps.
An AdEdge AD-IN chemical feed  module using liquid sodium hypochlorite via an in-line injection is introduced ahead of the filtration system with a chlorine feed and monitoring system to enhance the removal process. The PLC initiates backwashing of the AD26 treatment system twice daily, depending on the incoming levels of manganese, to remove any suspended solids that may accumulate in the bed.
In addition to the backwash supply system, AdEdge also provided an H2Zero recycle backwash system  that reclaims 100% of the settled backwash water. The settled iron, manganese and suspended solids form a low-percent-solids sludge that can be dewatered and disposed of in a solid waste landfill. After the water is treated by the AD26 system, the water is then treated by a second AdEdge treatment system. The model GAC-4260CS-2-MVH utilizes AdEdge GAC (granular activated carbon) in a two-vessel carbon steel configuration in series. Each 42-in. carbon steel vessel contains 30 cu ft of GAC for polishing the water prior to discharge to the sanitary sewer.
The system was started up and commenced in March 2011. Since system startup, the iron and manganese levels have lowered below the EPA secondary MCLs of 0.3 mg/L and 0.05 mg/L respectively.
Richard J Cavagnaro is marketing coordinator for AdEdge Water Technologies LLC. Cavagnaro can be reached at [email protected]  or 678.835.0052.