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Ecodur 201: Gaffney Water Plant Case Study (Heritage Water & SE Diving)

Coating Water Plant

There are an estimated 14,748 publicly-owned treatment works in the US with a growing trend of reclaiming water for consumption. By 2010, California was already recycling about 650,000 acre-feet of water annually and the state aims to be doing a million ac-ft/yr by 2020 and two million by 2030.

This case study concerns the Victor Gaffney Water Treatment Plant in Upstate South Carolina which opened in 1952. It is fed with water from Lake Whelchel and is part of a water division that serves some 9,500 residential, commercial and industrial customers.

Problem
The structure was 66 years old and showing its age in two large tanks. The floors had a tar base that had been impregnated with sand, but most of the sand had gone. The walls were clearly very worn on the surface but still retained overall integrity.

The client wanted a protective sealant to stop further superficial erosion, but they only wanted a coating to a depth of 20 mils. Typically, Ecodur is applied to a depth of a minimum of 30 mils.

The other problem was timing. The work had to be done in the winter months when water demand was lower. With side by side tanks, it was vital that only one tank was shut down for the work so the plant could remain in operation. Each tank can handle a throughput of two million gallons a day.

Also, the coating to be used, had to safe for contact with water and not bleed in any toxic chemicals. It also needed to be robust when permanently submerged and stay adhered to the surfaces for what might well be decades of service.

Solution
VOC-free, non-toxic Ecodur 201S was selected for the spray application over a total area of 42,272 sq. ft. It has an NSF/ANSI Standard 61 certification for being safe in contact with human drinking water. Furthermore, it has three times the adhesion of most epoxy coatings and ongoing brine submersion tests have shown no measurable deterioration of Ecodur test samples after more than 20 years.

Ecodur has been widely used in the fracking industry where it has demonstrated very high performance in oil and production water tanks which often contain a cocktail of chemicals, many of which are highly corrosive to steel and can destroy many competitive coatings.

Being sprayable, this was essential for even application on vertical surfaces, particularly where the thickness was limited to 20 mils.

Application Results
Surfaces were pressure washed prior to spraying to remove any loose materials. The work was performed in two phases. The first phase was completed in seven days due to weather conditions. Heritage Water had the contract with SE Diving from Greenville, South Carolina, being the spray applicator company.

HeritageWater

It was reported that a competing coating product, such as a polyurea, could not have been used under the prevailing weather and temperature conditions. The applicator was also pleased he did not have to wear a respirator, just a dust mask, safety glasses and coveralls with limited exposed skin, as Ecodur is VOC-free. With other products he has often experienced headaches from fumes.

The spray process, which involved some warm up of product and equipment because of the winter conditions, was also reported to have gone well with the minimum of down times.