By: Andy Smith

Before governments began monitoring wastewater discharges and long before it was popular to be “green” in your process, a Swedish company named Wirsbo partnered with ECOsmarte to solve both a process wastewater problem and develop a system to reuse the process water.

Wirsbo, founded in 1694 in Sweden is most famous for its world leading in-floor radiant heat tubing. ECOsmarte, founded in 1994 is the world leader in residential swimming pool purification without the use of chemicals, using natural oxygen and ionic copper through hydrolysis.

Wirsbo manufactures it’s tubing through a robotic extrusion process, cooling the tubing in water troughs fed 24/7 by the robots. Because of the high temperature, and the open air trough, the cooling water in the trough was black and oily, with a burning odor. The trough itself had string algae 1-2” thick on the sides. Minnesota Water Treatment arrived with ECOsmarte in 1996 to design and develop a chemical free system.

Wirsbo has a 50 year warranty on their tubing, the use of chlorine or other chemicals degrade the life of their product. Tests on the tubing after cooling were employed and the ionization and natural oxygen were confirmed neutral on tubing life.

Minnesota Water Treatment and ECOsmarte not only solved the “black water” cooling trough issue, a recirculation strategy was ultimately developed allowing water to recirculate through 60 ton EVAPCO cooling towers and chiller bundles in later years.

“In addition to the extreme black water on install, it was determined that fusaria and nematode infestations to the cooling trough water existed as loading dock doors allowed these common spores to enter the open trough water on each robotic process line.”

ECOsmarte and Wirsbo implemented programmable controllers and an ionization test (a simple 5 drop reagent) on every shift to prevent recurrence of the microbes.

Glass media was implemented in 2006 at flow rates of 60 GPM to 400 GPM to further lower microns of filtration and maintenance cost. Filtration has evolved from bag to DE, DE to Zeolite, Zeolite to Glass over the 13 year site history, with Glass media extending both media life and reducing backwash by 50%. The glass media is used in Pentair TA 60, TA 100 and TR 140 low pressure, high flow rate sand filters with high flow rate valves. Two years without rebedding is now historical on the glass.

The use of ASAHI differential pressure valves has allowed a headered bank of filters to automatically shift filters for backwashing at the convenience of on-site personnel. Previous bag filter systems did not permit the recirculation and rinse of the water and would shut down flow in the troughs requiring cleaning or change out to continue manufacturing tubing. In 2009 a 400 GPM loop has performed flawlessly.