The Tarboro Water Treatment Plant, built from 1937 to 1938, serves approximately 14,000 people in Tarboro, NC, as well as some of the surrounding rural areas. Originally, the plant had rapid sand filters with a total capacity of 1.5 mgd. It was upgraded in 1958 increasing the plant’s capacity to 3 mgd. In 1979, the filters were converted to a dual-media consisting of a nine inch layer of filter sand beneath a twenty inch layer of filter anthracite, again doubling the capacity to 6 million gallons per day.
The most current rehabilitation begun in 1997 and will be completed in 2000. Unifilt’s portion of the work on this project originally consisted of the removal of the existing anthracite, and replacement with a new Unifilt dual media anthracite.
Work begun in the spring of 1999 with the removal of the anthracite in filter number one. However, the project was placed on hold due to a shortage of water during the warmer months. Unifilt abated the dilemma by placing new anthracite in only one filter and shutting down the work for the summer.
While removing the anthracite from the first filter, it became apparent to the experienced Unifilt personnel on site that the support system beneath the sand was mounded, and in a state where failure was imminent. Further investigations by Heyward, Inc, and The Wooten Company (the Engineer) confirmed Unifilt’s conclusions, and a full replacement was requested.
Mother Nature then provided another obstacle for the Tarboro Water Treatment Plant. On Labor Day, Tarboro received approximately 10 inches of rain which put the rivers at or above flood stage. Then a week later on September 17th, Tarboro received over 20 inches of rain in just a little over 24 hours sending the Tar River over its banks. The experts called it a “500-year flood.” The first floor of the water plant was under water, but fortunately no significant damage occurred. The filters were not damaged, but remained off line for seven days. The reservoir, however, was unavailable for about a month.
Finally, Unifilt was able to return and complete the total filter material replacement, including ceramic balls, gravel, sand, and anthracite. With the requirement that only one filter could be out of service at a time, and the limited availability of backwash water, this project was completed in 18 working days without disrupting plant operation.
Unifilt is committed to completing all projects in a professional and timely manner. Unifilt field personnel have over 15 years experience in removal and installation of filter media. Unifilt has the capability to perform minor repairs to the underdrain, and can completely change underdrains when necessary.
Rely on Unifilt – call us toll free 1-800-223-2882. Unifilt understands your challenges and is committed to exceeding your expectations.