york river treatment plant, expansion phase 1

The existing treatment plant was expanded to include a complete Denitrification Facility that consists of nine denitrification filters measuring 11’-6” wide x 100’ in length. Each of these has an underdrain filter bed with air agitation, five layers of differing gradations of gravel and a six foot deep layer of filtering sand. Flow is introduced through a series of influent pipes to each individual filter and each filter has the ability to be independently back washed and cleaned. To support the denitrification process a complete methanol feed tank and pump system was added to feed methanol into the filtering process. Since the process was added into an existing treatment facility the hydraulics of the plant will be changed to allow gravity flow to the plant discharge. To accomplish this, a new Intermediate Pump Station was added that can intercept flow from the new Secondary Clarifier Diversion Box and pump up to 40 MGD with new variable speed vertical turbine pumps to the Denitrification Facility. The new Denitrification Facility also required an upgrade in the entire plant electrical feed and emergency power feed. Part of the project includes a new Electrical Generator Building that housed the new plant utility feed and a new 2275 KW generator as well as dismantling, refurbishing and reinstalling a 1360 KW generator into the new facility.  A new Electrical Power Center distribution building was also being added. With the addition of the new Denitrification Facility there was a conversion to a Distributed Control System to operate the plant and all the new instrument, valve, and process equipment control to operate the entire facility.