The Encina Wastewater Authority is based in Carlsbad, California and serves over 400,000 residents and regulates approximately 600 businesses in a 125 square mile service area of northwest San Diego County.
The Authority takes its mission seriously: to deliver cost-effective services to its patrons and act as good stewards of the natural environment. Careful forecasting and planning go into every capital expenditure so Encina’s facilities operate at maximum output with a minimal footprint.
Over the years Encina has upgraded its elaborate network of tanks, treatment systems and pumping stations with an emphasis on performance, safety and aesthetics. The facility has eight 35’ x 300’ aeration basins, where organic material in wastewater is broken down by activated sludge containing microorganisms. Each basin requires a secure cover that will prevent odors from escaping, is safe for operations and maintenance staff and also pleasing to the eye.
When it came time to upgrade the aeration basins, capital projects manager Jimmy Kearns remembered the positive experience the Authority had with CST.
“Our first experience with CST was on the rehabilitation of an influent junction structure,” says Kearns. “We were impressed with the look and feel of the CST cover, the quality and overall experience.”
Kearns continues, “The old covers on the aeration basins, dating back to 1982 and 1992, had exceeded their useful life. Water had infiltrated, they were UV damaged and unsafe.”
Encina’s facility is in a high visibility location – bounded by the I-5 freeway, beachfront residential property and several small businesses – which means every component of its treatment system must be pleasing to the eye and odor-free.
Safety is also a key issue. Like any employer, Encina has restrictions on the amount of weight that can be lifted by staff, so Kearns and the engineering team put a lot of thought into how easily the cover system could be handled.
“One of the advantages of the CST flat cover is the cost associated with the manual effort of removing and replacing it,” says Kearns. “With the old covers, for removal, staff were required to wear a full body fall harness, tied off to fall protection. Now when they need to conduct a visual inspection or access the basins to perform maintenance they can safely remove the covers from the outside of a guardrail perimeter. The reduction in injury risk and fall potential is huge.”
He continues, “It can look great from the designer’s or builder’s perspective, but it all comes down to the operator being able to work with the cover system on a daily basis. Ultimately, that’s the consideration.”
