Nashville Solves CSO Floatables Problem

Dec. 28, 2000
Problem Solvers
When the Nashville, Tenn., Metropolitan Government needed a cost-effective solution to remove floatables from their the combined sewer overflow (CSO) system, they selected the patented Netting TrashTrap system supplied by Fresh Creek Technologies, Inc. of West Caldwell, N.J.

"Floatables are ugly and unsanitary litter that is washed from sanitary and storm sewers into water bodies," noted Richard Turner, president of Fresh Creek Technologies, Inc., adding that his system is "a very effective and proven means to collect, capture and dispose of floatables." During a prior demonstration project sponsored by the U.S. EPA, the Netting TrashTrap system removed 95 percent of the floatables in the CSO.

The Nashville installation will capture floatables discharged at the Kerrigan Street CSO outfall on the Cumberland River. Similar Netting TrashTrap systems also are installed in Newark and Trenton, N.J.; New York City; and Louisville, Ky. Numerous other cities throughout the United States and Canada also are planning to install these systems.

Features of the Nashville project include:

  • The Kerrigan Street CSO outfall is very large - a 16.5 ft. diameter pipe with peak velocities as high as 11 ft. per second which means that the discharges reach a rate of 1,500 million gallons per day.
  • The capacity of the system - a total of ten bags - makes it the largest single application of the Netting TrashTrap technology to date.
  • The 25 ft. range of the Cumberland River from normal low pool level of 385 feet above sea level to the 100-year flood elevation of 410 ft. The system which floats in the river facing the mouth of the CSO outfall can accommodate this range through the use of a unique anchoring system.
The Netting TrashTrap system is one of many projects Metro has implemented to be in compliance with the USEPA CSO policy and the Tennessee Department of Environment and Conservation regulations. CTE Engineers in Nashville manages the overall CSO project for Metro.