Treatment system reduces nitrate level at food processing plant
In July 2011, AdEdge Water Technologies LLC  was selected by CET Eng. Services and the client via a competitive bidding process to design, manufacture and start up a packaged nitrate removal system for a food processing plant located in Lancaster County, Pa. The existing water system is 0.7 million gal per day, consisting of a single well pump feeding multiple atmospheric storage tanks coupled with final UV disinfection at a design flow rate of more than 500 gal per minute (gpm). The raw water has an average nitrate level of 14 mg/L, well above the U.S. Environmental Protection Agency primary maximum contaminant level of 10 mg/L.
“Occasional nitrate levels above the maximum contaminant level of 10 mg/L meant that employees had to be provided with bottled water as an alternative to drinking the tap water,” said Peter Lusardi, P.E., BCEE, senior project manager at CET.
The AdEdge  treatment system was designed to handle only a proportion of the total flow for optimal media use and regeneration frequency. To accomplish this, the nitrate system incorporates a bypass line that blends the treated and untreated water to attain a blended nitrate concentration at set point of less than 8 mg/L. The system features a skid-mounted AD-NO3 anion exchange package unit sized for a maximum design flow of 350 gpm. The model APUNO3-5460CS-3-AVH is a triplex, three-vessel carbon steel configuration in parallel. Each treatment vessel contains the strong base anion AD-NO3 IX nitrate removal media, which is NSF 61 certified. The resin is supplied in the chloride form as moist, tough, uniform spherical beads. After being treated in parallel by the three vessels containing the AdEdge  AD-NO3 IX media, the water is further subject to disinfection using UV technology before being stored in a 30,000-gal tank. The system was furnished complete with a brine regeneration system to regularly regenerate the AdEdge  AD-NO3 IX resin to maximize the efficiency in removing the nitrates. All regeneration cycles of the treatment system are automated by the programmable logic controller.
The system is equipped with automated control valves and harness, central PLC and control panel and a color user interface screen. System features also include differential pressure monitoring, local gauges, flow sensors and totalizers and a central hydraulic panel with sample ports for a complete functioning packaged unit. A continuous online nitrate monitor is provided with the unit for ease of operation and to provide continuous monitoring for compliance.
Meeting Treatment Goals
The system was started up in December 2011. Since the system began operation, the nitrates have consistently been reduced from around 14 mg/L to well below the treatment goal of 8 mg/L.
“The system and water supply are working fine,” Lusardi said. “We are pleased with the results and I would specify [AdEdge’s] equipment in the future.”
Richard J. Cavagnaro is marketing coordinator for AdEdge Water Technologies LLC. Cavagnaro can be reached at firstname.lastname@example.org  or 678.835.0052.