||This report documents the activities performed and the results obtained from the arsenic removal treatment technology demonstration project at the Orchard Highlands Subdivision site in Goffstown, NH. The main objective of the project was to evaluate the effectiveness of AdEdge Technologies AD-33 media in removing arsenic to meet the new arsenic maximum contaminant level (MCL) of 10 .g/L. Additionally, this project evaluates: (1) the reliability of the treatment system (Arsenic Package Unit (APU)-GOFF-LL), (2) the required system operation and maintenance (O&M) and operators skills, and (3) the capital and O&M cost of the technology. The project also characterized the water in the distribution system and process residuals produced by the treatment process. The treatment system consisted of two 18-in-diameter by 65-in-tall fiberglass reinforced plastic (FRP) vessels in series configuration, each containing approximately 5 ft3 of AD-33 media. The media was an iron-based adsorptive media developed by Bayer AG under the name of Bayoxide 33, which was labeled as AD-33 by AdEdge. The system was designed for a peak flowrate of 10 gal/min (gpm), based on the pump curve provided by the facility, and an empty bed contact time (EBCT) of about 3.7 min per vessel. The actual average flowrate of 13 gpm was 30% higher than the peak flowrate. The higher flowrate decreased the EBCT from 3.7 to 2.9 min, which might have contributed, in part, to earlier than expected breakthrough of arsenic. The AdEdge treatment system began regular operation on April 15, 2005. Between April 15, 2005, and August 6, 2007, the system operated at an average of 5.3 hr/day for a total of 4,559 hr, treating approximately 3,459,000 gal of water. Two test runs were conducted with Run 1 (from April 15, 2005, through September 6, 2006) treating approximately 2,085,000 gal and Run 2 (from September 6, 2006 through August 6, 2007) treating approximately 1,374,000 gal. Flowrates to the system, calculated based on daily totalizer and hour meter readings on the lead vessel ranged from 9 to 16 gpm and averaged 13 gpm.