In late 2009, Water Works Engineers contacted AdEdge to design and implement an arsenic, iron, and manganese removal system to serve the City of Aurora, Oregon. The existing water supply consisted of three wells feeding into a centralized distribution system with a maximum combined capacity of 500 gpm. The site had an arsenic level of 12 ppb, above the EPA’s MCL of 10 ppb. The City of Aurora also had iron and manganese levels of 0.9 mg/L and 0.189 mg/L, well above the secondary MCLs of 0.3 mg/L and 0.05 mg/L. AdEdge worked closely with Water Works Engineers and Ashley Engineering to supply the treatment system, backwash recycle pump skid and components, chemical feeed, and instrumentation. AdEdge also furnished the system with a PLC communications module to perform the automated functions needed for proper operation of the control valves. They system was constructed and commissioned in the Fall of 2010.
The AdEdge treatment system featured a skid-mounted AD26 oxidation and filtration packaged unit sized for a maximum design flow rate of 500 gpm. The model APU26-7260CS-3-AVH utilizes AdEdge ADGS+ media in a three vessel carbon steel configured in series. ADGS+ is a manganese dioxide coated silica media which is NSF 61 certified and used for the removal of arsenic, iron, and manganese. Chlorine is injected ahead of the treatment unit via a chemical feed module to oxidize As(III) to As(V) for optimized performance.
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, flow sensors and totalizers, and sample ports for a complete functioning packaged unit. Each 72-inch diameter treatment vessel contains approximately 84 cubic feet of AdEdge ADGS+ oxidation/filtration media. Backwashing of the systems occurs every three to four days based on the incoming levels of iron and manganese. Water exiting the treatment system feeds the 300,000 gallon storage tank and distributed to end users.
The system was started up and began operation in November 2010. Since the installation of the system, the arsenic, iron, and manganese levels have been treated to below the treatment goals of 10 ppb, 0.3 mg/L, and 0.05 mg/L respectively.