A resource management specialist in Scotland has invested in an innovative solution to protect and cover a water tank. 

Brewster Brothers Ltd specialises in recycling construction waste to offer products such as sand, gravel, soil and hardcore. As part of their aggregate washing process the business uses considerable amounts of water provided by a bore hole at the site. This groundwater is stored in a 32-metre diameter, one-million-gallon steel tank.

The water in the tank was being affected by algae which was blooming as a result of direct sunlight. “We needed to find a cover to stop the algae growth, which was choking our pump filters, but we also wanted to keep the cost down,” explains co-owner, Scott Brewster. After some searching, he chose Hexa-Cover, an flexible and adaptable product that can cover any body of liquid and prevents more than 95% of the surface being exposed to sunlight. The recycled polypropylene hexagonal sections pieces float on top of any liquid and fit together to block light out. The product is heat, frost, and wind proof, and has a life expectancy of 25 years.

The family has a farming heritage and Mr Brewster came across Hexa-Cover when searching for solutions to covering a disused slurry tank, which he had converted to store water. “It is an agricultural tank so I wanted to see if the manufacturer or another company in agriculture could supply a plastic cover or something similar,” he says. “Having established the high cost of buying a cover I came across videos online of plastic disks being used cover liquid and contacted the UK supplier Tramspread,” he adds.

A PVC cover for the 23-metre diameter tank could have cost Mr Brewster as much as £50,000 but Hexa-Cover was less than half of this and equates to £22 per square metre. “We looked at the option of having a pole in the middle of the tank that the cover attached to, but because of the high winds in this part of Scotland we were concerned about wear and tear. We also considered an inflatable cover that would go up and down with the water-level, but again we were concerned that rainwater would build-up on top of it,” he explains. Hexa-Cover requires no maintenance and the pieces are heavy enough to not be affected by the elements. “To have something that simply does the job without having to be checked or maintained is a real benefit to us,” he says.

Hexa-Cover comes in two sizes and is manufactured by a Danish company of the same name. The larger size has a diagonal measurement of 228mm and each piece weighs 243 grams. It is supplied in 275 kilo bags which can be easily emptied into any liquid. “All we had to do was give the dimensions of the tank to Tramspread who calculated how many bags we would need. When the bags arrived, we simply tipped them in to the tank. Each of the pieces floated on the top and began to interlock and cover the surface until there was no space left which made the installation was very quick and easy,” says Mr Brewster.

The product was installed in the spring of 2020 when temperatures and hours of sunlight were much higher than normal. “It was a very sunny and hot spring, so we are grateful to have found this solution to protect our water store. Water is fundamental to our process and we have now reduced maintenance down-time by preventing the build-up of algae in our pumps,” he concludes.