Award of Merit: Water Structures Category
What's On Tap? Structuring Water Quality
Submitted by JQ
City of Denton
H and H Restoration
Fort Worth, TX
Originally constructed in 1957, the Lake Lewisville Water Treatment Plant (LLWTP) served the growing population of the cities of Denton and Lewisville. After multiple renovations through the years, the plant grew more than sevenfold in capacity to meet the dramatic rise in consumer demand. In a major effort to improve operation reliability, reduce maintenance costs, and update processes to meet current water quality standards of the Texas Commission of Environmental Quality (TCEQ), plans were implemented to construct improvements to meet these primary objectives.
A critical part of this endeavor was structural evaluations and improvements to various aged process facilities, including the flocculation/sedimentation (floc/sed) basins, filters, and associated distribution conduits. Structural condition assessments indicated widespread concrete matrix loss and pitting up to 1 in. (25 mm) deep on the majority of containment wall surfaces throughout the floc/sed and filter complex. Petrographic testing revealed carbonation up to 1/2 in. (12.7 mm) deep on the majority of concrete surfaces. Given the wide area of surface deterioration, a spray-applied, cementitious repair mortar was selected to restore the surface of the concrete walls. A strict quality control and testing program was implemented to ensure repairs were properly applied.
Extensive coordination and careful sequencing with plant operations were necessary during construction to minimize construction cost and delays. The scale of repairs was significant, dictating the need to accurately estimate, sequence, and execute repairs while minimizing the effect on the plant operations, construction schedule, and the owner’s budget. The result was a fully restored basin complex serving its part in the City of Denton’s mission to deliver the highest quality of treated water.