South Rivanna Water Treatment Plant Improvements
Over the past decade, the South Rivanna Water Treatment Plant has undergone significant improvements. It received GAC pressure vessels, which help remove additional impurities from the drinking water. Other significant improvements include: a new alum and fluoride storage facility; installation of two additional filters to meet firm capacity needs and new filter control panels; building around the lime storage facilities; the addition of a second variable frequency drive at the Raw Water Pump Station as well as other general pump station improvements; the relocation for the electrical gear from a subterranean location at the Sludge Pumping Station to a new aboveground enclosure; a new administration building on site for additional office, meeting, and storage space; finished water pump improvements and the addition of variable frequency drives to three of the pumps; sedimentation basin improvements; replacement of filter inlet valves and actuators; remodeling of the existing filter building for better lab and control space and painting throughout; new clarifier drives; and incoming electrical system improvements for the facility. These upgrades have improved the reliability and resiliency of the plant, particularly at higher flow rates.
Observatory Water Treatment Plant Improvements
The Observatory Water Treatment Plant was originally constructed in the mid-1950s. Based on a Needs Assessment Study, the plant underwent a comprehensive upgrade, including improvements to the flocculators, sedimentation basins, filters, and chemical feed facilities, to enhance future reliability and resiliency. In addition, the existing reinforced concrete flume, which conveys treated water from the sedimentation basins to the filters, was replaced. Filter control valves and piping were also replaced, and the electrical and SCADA control systems were upgraded. A portion of these upgrades were completed during the Granular Activated Carbon (GAC) project, where the flocculator systems were upgraded with new mechanical and electrical equipment, including variable speed drives for optimal efficiency. In addition to providing necessary equipment upgrades, these improvements have increased the plant’s capacity from 7.7 million gallons per day to 10 million gallons per day, providing the needed reliability and redundancy in the Urban Water System. As part of this capacity increase, the plant’s GAC treatment capacity was increased as well, with the addition of four GAC contactors.
Crozet Water Treatment Plant Improvements & Beaver Creek Dam Alterations
The Crozet water treatment system is currently permitted and rated to supply up to 1.0 million gallons per day (mgd) of water to the ACSA distribution system. Over the past several years, average day usage of water has increased steadily, with maximum day demand approaching plant capacity. In addition, much of the existing plant systems are the same as when the plant was constructed in the 1960’s. The improvements include increasing the plant’s capacity to 2.0 mgd.
RWSA operates the Beaver Creek Dam and reservoir as the sole raw water supply for the Crozet Area. In 2011, an analysis of the Dam Breach inundation areas and changes to Virginia Department of Conservation and Recreation (DCR) Impounding Structures Regulations prompted a change in hazard classification of the dam from Significant to High Hazard. This change in hazard classification requires that the capacity of the spillway be increased. Work for this project will be coordinated with the new relocated raw water pump station and intake.