Especially during high-demand periods, the North Lauderdale Water Association of Bailey, Mississippi, was challenged to remove iron from its drinking water.
When first established in 1966, the association’s footprint consisted of a single well pumping 250 gallons per minute, one iron-removal filter, about 62 miles of distribution lines and two 200,000-gallon storage tanks.
Today the association includes seven wells and four iron-removal (?) treatment plants. Distribution lines have grown to cover about 800 miles and there are six storage tanks, for a combined treatment of 3,120 gallons per minute and storage of 1.2 million gallons.
The problem at the water treatment facility was that the treated water was short-circuiting filters, says Stanley Spradling of Calvert Spradling Engineers, West Point, Mississippi.
The reason for it happening was inadequate storage. During high-demand periods, treated water was sucked through the filters. This prevented them from working efficiently to remove the iron and other organics.
Spradling and his colleagues modified the treatment process for additional storage capacity, allowing the treated water from the filters to gravity flow into a clear well tank. But for that, a tank was needed.
Costs sunk in concrete
The wrinkle there was that the price for the kind of concrete storage tank that it was first assumed would be used for the project turned out to be significantly higher than budgeted.
That gave Southeastern Tank of Lebanon, Tennessee, an opportunity to furnish a quotation for a glass-fused-to-steel tank, says that company’s Marc Nichols.
It did so after determining that a 59 ft. x 10 ft., 200,000 gallon Aquastore tank from CST Storage would support the modified treatment process. And on that basis, Southeastern Tank was awarded the project.
In order for the gravity-fed system to work with an above-ground tank, the plant site had to be reworked to help with drainage. Control ditches and drainage pipes were installed. Backfill was not required as a means to partially bury the tank. That saved construction time and money.
The tank was completed and installed on-time.
As noted, the additional storage means the plant can now pump treat 800 gallons per minute and store 1.2 million gallons per day. In addition, iron further settles out in the tank, helping to improve water quality for 4,000 customers.
Accurate lead times mentioned
Spradling says the association "is extremely pleased with the performance of the Aquastore. The interior and exterior coatings have stood up well and the tank is pretty well maintenance free."
Besides its fast, economical construction and low maintenance costs – the tank never needs painting – its additional storage helped ensure adequate iron removal from the drinking water.
The Southeastern Tank Team is "professional, with especially good attention-to-detail," Spradling concludes. "They do an excellent job providing accurate estimates as many projects have a one- to two-year lead time."
CST Storage is a global provider of modular, factory-coated bolted storage tanks for dry-bulk and liquid applications in municipal, industrial and agricultural markets. The company is the result of the merger of Engineered Storage Products Co., producer of brand names Aquastore, Harvestore and Slurrystore, with Columbian TecTank (CTT). The company has several fabrication and engineering centers in the U.S. Its headquarters is in Kansas City, Missouri.