SUD Gets Update on Constructed Wetlands
Thursday, June 22, 2017
by Leslie Lytle, Messenger Staff Writer
At the June 20 meeting, student researchers updated the Sewanee Utility District Board on the Constructed Wetlands project located at the SUD Wastewater Treatment Plant (WWTP), a pilot study undertaken jointly by the University of Georgia (UGA) and the University of the South, examining wetlands’ effectiveness in removing contaminants and noxious nutrients from wastewater.
Water is pumped from the WWTP lagoons into a supply tank that feeds three sequential basins planted with native Tennessee species known to be effective in absorbing nutrients. This summer marks the first year of the wetlands operation.
Environment and Sustainability major Megan Hopson, a May graduate of the University of the South, said her thesis project looked at the wetlands effectiveness in reducing nitrogen, phosphorus and E. coli bacteria. Tests showed dramatic decreases in nitrogen and bacteria levels and modest but significant decreases in levels of phosphorus. Phosphorus is retained in sediment, Hopson explained, making it necessary to monitor data over several years to accurately interpret results.
Data showing a leveling off, or plateau effect, in nutrient removal over time suggested a need to replace the plants in a basin, Hopson said.
In addition to efficacy in absorbing nutrients, “plants were selected for their tolerance to water depth in the basin where they were planted, beauty, and the ability to attract pollinators,” said biology professor Deborah McGrath, who along with forestry professor Scott Torreano, heads up the Sewanee research team.
Charged with developing and implementing a public outreach campaign, UGA graduate student Philipp Nussbaum said the historic drought of 2007 spawned the project as researchers began to look at wastewater treatment with a view to possible water reuse.
The advantages of wetlands wastewater treatment are superior effectiveness in removing nutrients and low operating costs, Nussbaum said.
“A constructed wetlands system could replace the SUD spray-fields wastewater treatment method,” Nussbaum speculated.
One of the questions researchers hope to answer is whether further treatment by spray-field application is necessary to achieve water of potentially potable quality.
The water from the SUD wetlands is returned to the lagoons.
Making a comparison to the water-reuse concept, board member Karen Singer noted that water slated for treatment as drinking water is frequently drawn from rivers in which upstream communities discharge treated wastewater.
SUD manager Ben Beavers was quick to point out, “We’re not doing this tomorrow.” SUD currently has no plans to pursue implementing water reuse practices.
Nussbaum said a 2015 survey of the Sewanee community showed that most people were unaware of what happened to their water after it went down the drain. He directed those wanting more information about the wetlands to the project website at <sewaneewetlands.org>.
The board requested annual updates on the project and expressed an interest in serving on an advisory committee charged with heightening public awareness about the community’s water supply.
In other business, Beavers updated the board on easement contract negotiations for the Cooley’s Rift development. Beavers said the SUD attorney was drafting a contract calling for a common rather than an exclusive easement requiring at least three feet of separation between SUD lines and lines from other utility providers. Beavers will present the finalized contract to the board for approval. He anticipates construction will begin in Aug.
The Midway pressure boosting station was in the final stages, Beavers said. “Everything is ready to go except for connecting the electrical and smoke testing.” Signing of the final easement necessary for completion of the project is expected in the near future. The SUD board meets next on July 25.