Sep 01, 2009

Meeting a New Standard

AdEdge Technologies, Inc. (AdEdge) was selected in 2006 by McCrone Engineers and the awarded contractor, Maryland Construction, to design, build and install a full-scale AD26GS+ arsenic, iron and manganese treatment system for their customer Foxxtown Apartments in Sudlersville, Md., to meet the new U.S. Environmental Protection Agency (EPA) arsenic standard.

The treatment system was based on the design rated for 50 gal per minute (gpm) in order to treat the water from both wells. Incoming arsenic concentrations were tested at 24 ug/L, while iron tested at 0.12 mg/L and manganese at 0.22 mg/L. Water is treated prior to entering two pressurized storage tanks that feed distribution.

AdEdge provided the necessary design and construction-related submittals, working closely with McCrone Engineers to implement the project. As part of their package, AdEdge also provided turnkey installation services through Delaware Water Technologies for the system and provided the overall master system control panel and PLC.

Systems Installed
AdEdge furnished the integrated packaged treatment system capable of treating up to 50 gpm design flow. The system consists of two 30-in. outside diameter by 60-in. ASME pressure vessels in parallel configuration with electric control valves, control panel, pressure gauges and automatic PLC controls (shown at the right) and the AD26GS+ media.

The process also utilizes two continuous chemical feed modules consisting of ferric chloride and chlorine to augment the natural iron in the groundwater and chlorine to optimize arsenic removal in the media bed. Hypochlorite is also utilized to oxidize the Arsenic (III) to Arsenic (V) and to aid in iron and manganese removal. The coagulated arsenic and oxidized iron and manganese particulates are removed in the media bed as the water flows through the media bed. These particulates are then backwashed from the filters regularly.

In addition, a PLC control panel controls the entire operation of the filter system using an Allen Bradley PLC. The master control panel includes a door-mounted Panel View 1000-color touch screen to allow automatic and manual control monitoring of the filtration cycles. The filter PLC also monitors flow and differential pressures while controlling two well pumps, chemical dosing systems, signals from the hydropneumatic tank level transmitters and the air compressor. Backwash water supply is provided via the pressurized storage tanks.

Performance Results

In early August 2007, the AdEdge AD26GS+ coagulation/filtration system was installed and commissioned into full operation. AdEdge and Maryland Construction conducted the plant startup and reliability testing following shakedown of the system.

Maryland Environmental Services is the site’s certified operator contracted to perform regular testing and monitoring of the system. Field tests showed that arsenic, iron and manganese all were removed to non-detect or below detection levels. The treatment plant has run in automated mode per specifications with 100% success. The system is monitored regularly with no known issues.

Goodbye, Gravel