The Rivanna Water & Sewer Authority board of directors has authorized testing and preliminary design for the use of granular-activated carbon as a secondary water disinfectant for Charlottesville-Albemarle’s urban drinking water.
The action at Tuesday’s monthly RWSA meeting follows last month’s reversal, by the “four boards” that manage the area water supply, to drop consideration of the use of chloramines. Public feedback at numerous community meetings since March had been strongly opposed to the addition of chemicals to the water supply.
“I think we have a game plan and a schedule to move the project forward,” said Gary O’Connell, executive director of the Albemarle County Service Authority. “From what we were presented today, we have a good plan and we are moving forward as the community had asked.”
The board agreed to retain the firm Hazen and Sawyer at a fee not to exceed $427,190 to conduct pilot testing of a hybrid carbon filtration approach and to develop a contingency plan for water treatment needs between now and completion a new system.
“In the research that we have done, granular-activated carbon seems to be a very good approach,” O’Connell added. “It is well accepted around the county as a good way to treat water and … to meet the new [Environmental Protection Agency] rules.”
The hybrid option would involve running portions of the water treatment plants’ capacity through carbon filtration systems, then combining it with regularly treated water for disinfection. At their July 25 meeting, the four boards asked Hazen and Sawyer for a cost estimate on the hybrid option.
In the report presented Tuesday, Hazen and Sawyer said the capital costs for carbon filtration ranged between $7.94 million to $15.1 million, as compared with their earlier estimate of $18.3 million.
The highest cost was based on the water treatment plants running 365 days a year at their full capacity, whereas the new estimates cover capacity ranges of 25, 50 and 75 percent combined with some seasonal shutdowns in winter.
“The range was not a surprise to me,” said the RWSA’s executive director, Thomas L. Frederick Jr. “I am trying to present to our board and our community as many options as I can … depending on how far we want to go with this technology.”
Frederick presented the board with a four-year timeline for the design and implementation of GAC facilities. Such an effort will require the RWSA to secure a two-year extension on meeting what are called EPA Stage 2 regulations for disinfection byproducts.
Hazen and Sawyer will next conduct one year of field tests at each water plant to develop a preliminary engineering plan by January 2014. Construction of GAC facilities would not begin until July 2014, with completion expected in September 2016.
Later this fall, the RWSA board will review a price estimate for the system’s preliminary design. Design and engineering work will be conducted simultaneously with the year of pilot tests. Final costs for carbon filtration will not be known until early 2014.
Sewer system upgrades
|
|
In other business, the RWSA board received a detailed report on joint efforts by the city of Charlottesville, Albemarle County and the RWSA to repair and upgrade sewer systems to help eliminate overflows into local streams and rivers.
In 2010, joint goals were set for eliminating sources of water infiltration and inflow into sewer pipes, water that should not be treated at the wastewater treatment plants. In periods of severe weather, stormwater can overwhelm the treatment system’s capacity.
“There’s been a tremendous amount of effort put in on the total system improvement,” said Jennifer Whitaker, RWSA’s chief engineer. “We have seen 1.2 million feet of pipe inspected, we have relined 150,000 linear feet of pipe, and we have rehabilitated close to 2,000 manholes.”
Whitaker said that $125.2 million had been invested in sewer system improvements since 2009. The undertaking is required in part to comply with a consent decree with the Virginia Department of Environmental Quality to eliminate water pollution sources.
Frederick said when he first came to Charlottesville in June 2004, he was attracted by the environmental consciousness of the community.
“But one of the things that I saw … was a serious disconnect between our words and our actions because very little if anything was being done to rehabilitate our sewer system,” Frederick told the board. “I know that’s not the most sexy and glamorous topic to talk about … but it is an enormous benefit to the environment to have a well-run sanitary sewer system.”
It was a report worth celebrating said John Martin, a county resident and former member of the ACSA board.
“I think it shows people are working together under the consent decree and you have three government entities all watching each other’s backs,” Martin said. “They are doing a really good job.”
