GFRP Tanks Stand the Test of Time

Landfill storage tanks are built tough to withstand corrosion from the toxic materials they contain. Leachate, a highly corrosive liquid formed when rainwater moves through the landfill’s refuse, is particularly hard on these tanks. Collected and stored in the tanks for later treatment, leachate can eat through tank walls and leak out over time, contaminating the nearby soil and groundwater.

Six vertical FRP storage tanks at Waste Management Trail Ridge Landfill in Jacksonville, Fla., have survived this challenge for more than 35 years. Industrial Plastic Systems (IPS) custom manufactured the 13.5 x 18-foot tanks in 1990 using helical winding for the sidewalls. The tank’s flat bottom and domed top were produced separately and joined to the shell during fabrication. The tanks are made using Dow Derakane 411-350 standard bisphenol A vinyl ester resin and Owens Corning 366 Type 30 glass roving.

Integrated Environmental Technology (IET), which manages the environmental aspects of Trail Ridge landfill’s operations, hired IPS to perform routine inspections to ensure that the tanks remain in good condition. Randy Adkins, the company’s CEO, has seen his share of leachate tanks that haven’t performed up to par.

“I would see data from sites showing tank leaks, loss of landfill methane gas and all sorts of tank-related problems,” he says. “These are very large, cumbersome structures to fix and replace. These faulty tanks are dangerous to everyone and everything that comes in contact with them.”

The Trail Ridge Landfill tanks stand out for their excellent record. “The quality of the actual tanks, the inspection skills and the tidiness of the inspection reports were all really impressive,” Adkins says. “It certainly makes my job easier when a landfill is utilizing quality industrial solutions, such as these FRP tanks. They were still reliable even after facing decades of harsh environments.” 

Tank inspection is a visual process best done from inside the tank, says Michael Brown, the owner of IPS. “If there ever is a leak it will always be from the inside, and if there is a repair to be made, typically you'd want to make that repair from the inside at the resin-rich liner,” he says. “Because it is a confined space, we always go in with our Tyvek^® suits, air monitoring system and harnesses for retrieval in the event something happens.”  

Using technical data sheets for reference, the inspection team checks Barcol readings to determine the indentation hardness of the tank wall, takes air monitor readings and examines everything from hold down lugs and anchoring bolts to laminate side walls to uncover any signs of stress in the tanks. Despite 30-plus years of service, none of the Trail Ridge GFRP tanks have required repairs, only some routine maintenance such as the addition of new nozzles and instrumentation.

Brown says one reason for the tanks’ longevity was the careful selection of materials when his father Joe Brown and his business partner Barron Burhans ran the company. “There are three major things that they would have looked at before they selected a resin for a storage tank: the chemical, the concentration and the temperature,” says Brown. “In this case, they knew that temperature would be groundwater or atmospheric temperature, so nothing elevated. A lot of chemicals get much more aggressive when they're at 180 degrees F, but these were going to be maybe 100 degrees F max. That’s easier to handle.”

The pH of the chemicals and their concentration vary according to what is decomposing in the landfill at any given time, so the resin had to handle a wide range of chemicals and conditions. The 100-mil tank liner has also helped keep the tank intact.

Today, IPS continues to take advantage of new technologies that enable it to produce even stronger, longer-lasting leachate tanks, as well as GFRP buried lift stations, scrubbers and ducts for waste gas collection.

“FRP has a very, very unique combination of chemical resistance, storage and a price point that a lot of people find very attractive,” Brown says.

Their longevity is another big advantage; Brown doesn’t expect to have to replace the tanks at Trail Ridge landfill anytime soon.

“While these tanks have certainly outlived their expected service life that doesn’t mean they need to be replaced just for the sake of being replaced,” Brown says. As long as they undergo annual inspections, the tanks should continue to add to their three-decade record of excellent performance.