This is the first in a series of five articles providing an overview of major upgrades that OCWA—Central New York’s Water Authority–will be making to its Lake Ontario Water Treatment Plant (LOWTP) over the next several years. This first article will summarize the purpose behind the upgrades. Follow-on articles will discuss specific components of the project, such as the piloting phase, electrical system upgrades, pump station improvements and finally enhancements to be made to the LOWTP itself.
On January 1, 2017, OCWA finalized its historic operational consolidation with the Onondaga County Water District, combining the major wholesale and retail water operations in a five-county region of Central New York. As part of the consolidation, OCWA is now responsible for operating the critical Lake Ontario Water Treatment Plant (LOWTP), which can process up to 60 million gallons of clean, reliable water for Central New York residents on a daily basis. The Lake Ontario WTP is located in the Town of Oswego in Oswego County and was placed into service on June 1, 1967. It continues to reliably produce drinking water for more than half of the customers in OCWA’s five-county service area and serves as a backup supply to the City of Syracuse. Over the past 50 years the facility has been well maintained and operated. Despite this and excluding several small renovation projects, the majority of equipment has aged to the point where continued maintenance has become challenging and in some cases not readily achievable. Water quality regulations have changed dramatically since its inception and the facility overall is due for major reinvestment and upgrade.
OCWA SYSTEM OVERVIEW
Water originates from about a mile off shore in Lake Ontario via a shared, unlined stone intake tunnel. At a riser chamber on City of Oswego property the water splits to feed the City of Oswego WTP and OCWA’s Raw Water Pumping Station. Water is pumped about two (2) miles to the LOWTP, where it is filtered, purified and tested. The “finished” water is then pumped via the Clear Water Pumping Station to the Terminal Covered Storage Facility in the Town of Clay, from which it is transmitted to the east (Eastern Reservoir/Tanks), west (Western Reservoir/Tanks) and south to other consolidated storage facilities and connections.
The facilities encompassed by this project consist of select improvements at the Raw Water Pumping Station, comprehensive upgrade and improvement of the Lake Ontario Water Treatment Plant, storage tanks (clearwells and backwash), solids handling facilities and select improvements to the Clear Water Pumping Station. Additionally, there are two electrical substations that serve the facilities and require upgrade and integration of backup power generation.
The LOWTP’s original treatment processes consisted of rapid mix basins, solids contact clarifiers, and six anthracite over sand filters. The design provided a maximum capacity of 36 million gallons per day (MGD) with all filters in operation but was always envisioned to be expanded. As part of a 1979 expansion project, modifications were made to allow the plant to operate in the direct filtration mode which effectively doubled the plant’s filtration capacity. At the time, a rating of 72 MGD with all filters in service was granted by the New York State Department of Health. However, assuming one filter is out-of-service, the current plant capacity is considered to be approximately 60 MGD.
Although the LOWTP currently meets or exceeds all applicable water treatment standards and is in working order, the plant is now 50 years old. Many of the systems are at the end, or reaching the end, of their useful life. Due to its age, the existing equipment is less efficient than currently available equipment and replacement parts are becoming much more difficult and costly to procure, if available at all. There is also significant opportunity to improve operability and reliability of the LOWTP.