Date
Monday, September 9, 2024
Time
2:30 PM - 3:00 PM
Location Name
M111
Name
Huff, Puff, and Blow your Intake Screen Off! Airburst System Expansion at Nashville's Omohundro WTP
Track
Drinking Water Treatment
Description

Nashville Metro Water Services’ historic Omohundro Water Treatment Plant provides up to 90 million gallons per day (MGD) of treated drinking water, along with its sister facility K.R. Harrington WTP, to approximately 220,000 customers in the Metropolitan Nashville and Davidson County area. The pumping station and boiler house at Omohundro were first constructed in 1889, the filter plant completed in 1929, and the facility was added to the National Register of Historic Places in 1987. Since the first processes at Omohundro were constructed in 1889, raw water has been drawn from the Cumberland River at multiple locations and under various configurations. This presentation will provide a brief overview of the history of raw water intakes at Omohundro, their location and design, and their ultimate fate. Two intakes, Intake #2 and Intake #4, are currently in operation at Omohundro. Their design, operational and maintenance history, and Intake #2’s retrofitting with passive screens and an airburst system will be presented as background information to the Intake #4 airburst system expansion. During the presentation, the recently completed 2022-2023 expansion of the airburst system to Intake #4 will be described in detail including design, permitting, and construction challenges. Redundancy requirements for the airburst system and other space limitations drove many of the design decisions for the project. Permitting challenges included authorization from the United States Army Corps of Engineers for work within the navigable Cumberland River channel and the Tennessee Wildlife Resources Agency for an underwater survey for endangered mussels. Construction was primarily completed underwater by barge-mounted equipment and divers in order to install the new passive screen atop the Intake #4 crib and extend 12”-diameter air piping from the existing airburst system at the George Reyer Pumping Station to the crib located in the middle of the Cumberland River. During construction, settled debris within the crib, the 72”-diameter intake line, and the Intake #4 screening structure proved a near constant obstacle to construction progress, leak testing of the air piping presented challenges, and river conditions at times hampered marine construction activities. The completed Intake #4 project now provides Metro Water with redundant intakes, each designed to draw 90 MGD of raw water from the Cumberland River, with passive screens and an airburst system that are more reliable and operator-friendly than the previously-installed traveling screens.