Scott Candler Tank, Pump Station, and Transfer Pumps

Project Scope

This project had 3 steel reservoir tanks built from 1950 to 1970 that were responsible for holding 15 million gallons of potable water. That water was then dispersed to Dekalb County for customer use. In 2018, the 2nd reservoir tank’s roof started to collapse in on itself. Scott Candler Water Treatment Facility (SCWTF) set out to rebuild these old tanks and extend their lifespan. The tanks would have their coatings stripped, any damage discovered would be repaired, and the old roofs on tank 2 and 3 would be removed and replaced. The coatings would then be replaced both inside and outside to prevent any future rusting on the tank.

SCWTF’s high-speed distribution pump station also required the removal of several sections of corroded steel pipe, valves, and fittings.  The walls of the steel pipes were checked for thickness and found to be significantly thinner than designed.  A failure of this line would very likely cause a disruption of service for County residents.  Hundreds of feet of 54” buried pipe and pipe housed within the pump station were replaced and coated.     

Lastly, SCWTF requested the removal of 4 small pumps at their transfer station to be replaced with 2 larger more efficient pumps that would work together with 8 existing pumps. The 2 new pumps are powered by new variable frequency drives to lessen the stress on the pre-existing pumps.

Location:

Atlanta, Georgia

Client:

Scott Candler Water Treatment Facility

Challenge Faced

Tank challenges –

Cold and wet weather during coating operations.
Lead content in the existing paint required remediation and appropriate planning for environmental and employee health concerns.
Existing shut-off valves that would not hold.

High Service Pump Station Challenges –

The project required a 60-day shutdown window for this pump station.
The underground pipe had unknown utility conflicts that had to be coordinated in the field.
The pipe had to be ordered prior to excavation so buried miter joint angles were unknown. These had to be figured out and fit in the field.

Transfer Station Challenges –

Detecting existing wiring in the elevated slab.
Long lead time for new pumps (245 days after approved submittals)

Solution Provided

Tank Solutions –

Painters worked multiple weekends to catch up and finish on time.
Specialist company came in to remove the lead paint. Using full hazmat gear and wet sand blasted the paint, collected the paint debris in plastic tarps and disposed of it correctly.
Leaking valves required specialty, high-pressure plugs and very technical installation and removal.

Pump Solutions –

Ordered all the pipe ahead of time, pre-excavated and shored all underground piping, loosened flange bolts to assure they were not seized. Staffed the project with lots of welders and pipefitters. Completed shutdown in 45 days rather than allotted 60.
Pre-excavation and shoring allowed time for careful location of existing utilities and shoring as required.
Skilled tradesmen were tasked with making these mitered joints watertight and passing weld inspection.

Transfer Station Solutions –

After an unplanned power outage, conduit and wiring that were found in the core area for the new pump were temporarily rerouted for operational purposes and later a permanent routing was implemented.
Pump purchase and release of submittals were made in a timely manner which allowed for the long lead time for production.