Containerized treatment system reduced arsenic level below World Health Organization standard
Quilicura is a municipality located in the Santiago Metropolitan Region in Chile. Well No. 3 has a flow of 1,600 gal per minute (gpm), or 100 liters per second. The well has a high concentration of arsenic  that fluctuates between 0.040 mg/L and 0.060 mg/L, well above the World Health Organization’s standard of 0.010 mg/L.
In addition to the high arsenic concentration, the site has challenges with pH that ranges from 7.0 to 9.5.
EcoRiles contacted AdEdge Water Technologies  in 2013 to design, manufacture and start up an arsenic removal solution for the Quilicura municipality.
The AdEdge arsenic treatment solution consists of four WaterPOD containerized systems  rated for a combined total of 1,600 gpm. Each WaterPOD contains six 48-in. carbon steel vessels in a parallel configuration. The vessels are loaded with AdEdge Bayoxide E33 granular ferric oxide media. The E33 binds the arsenic to the media structure and does not lose that bond during backwash. The system has an ADIN chemical feed  dosing system that is mounted outside the WaterPODs.
The chemical feed dosing system consists of a sodium hypochlorite module that oxidizes the arsenic from trivalent to pentavalent. A second chemical feed module uses hydrochloric acid to lower the pH and improve media life.
Backwashing of the treatment vessels occurs every 45 to 60 days to prevent hydraulic channeling and remove any suspended solids that may have accumulated in the bed. Backwash operations are automatically controlled by an AdEdge InGenius control panel  with programmable logic controller and human-machine interface. The source of the water is treated from the outlet of the distribution pumps.
The WaterPODs were shipped in September 2013 to Quilicura and started up in November. The systems are treating between 1.5 and 2 million gal of water per day, below the World Health Organization’s standard of 0.010 mg/L.
Richard J. Cavagnaro is marketing coordinator for AdEdge Water Technologies LLC. Cavagnaro can be reached at [email protected]  or 678.835.0052.