Aeration systems account for between 25 and 60 percent of the energy costs of a typical wastewater treatment plant. Two recent tests in Sweden and the Netherlands, however, have shown that new technologies can reduce a plant’s energy consumption by up to 22 percent.
The results of two recent tests of Xylem’s Sanitaire product range have demonstrated that they can significantly reduce energy use. The first test, conducted in Sweden, showed that the energy consumption of a wastewater treatment plant’s aeration system can be reduced by up to 65 percent using Xylem’s Sanitaire Silver Series low-pressure diffusers. Another test, in the Netherlands, confirmed that Xylem’s Sanitaire Gold Series membrane diffusers can cut the energy use of a plant by up to 22 percent.
“Research shows that aeration accounts for between 25 and 60 percent of the total energy consumption at a typical municipal wastewater treatment facility,” says Patrik Brask, Manager of Product Management at Xylem. “Xylem’s Sanitaire products have been specifically designed to address this problem, by reducing the amount of pressure and energy required to deliver high-quality aeration.”
Sanitaire is a Xylem brand that provides diffused aeration and biological wastewater treatment solutions to help meet the growing challenge of clean water. With their reputation for securing high-quality, energy-efficient operations, Sanitaire-branded products have already been installed in thousands of municipal and industrial wastewater treatment applications worldwide.
Three times as efficient in Sweden
The first test was conducted by Xylem at the Sternö municipal wastewater treatment plant in southern Sweden, where aeration had previously accounted for 44 percent of the plant’s total energy usage. For the purpose of the study, a test line was installed using Xylem’s Sanitaire Silver Series low-pressure diffusers, a new blower and Sanitaire control system, while the previous line was maintained as a reference.
After six months of parallel operations, aeration efficiency was almost three times as high in the Sanitaire upgraded line compared with the reference line. Lars Larsson, Product Manager at Xylem, says, “These full-scale tests clearly demonstrate the benefits that Xylem can bring to wastewater treatment operations. Xylem’s extensive expertise in optimizing energy efficiency can reap significant rewards for our customers.”
Meanwhile, the trial also revealed that the cost of upgrading the system would be recovered within four years and that the new system reduced the total energy consumption of the plant by 13 percent. This would correspond to annual savings of €21,000 – or €46,000, if both the plant’s treatment lines were upgraded.
Increasing density in the Netherlands
The second field test was carried out from May 2010 to October 2011, at a municipal wastewater treatment plant run by Waterschap Noorderzijlvest in Zuidhorn, the Netherlands. In this trial, the installation of Xylem’s Sanitaire Gold Series membrane enabled the plant to reduce its total energy use by up to 22 percent, while delivering high-quality aeration.
The Sanitaire Gold Series can deliver these results due to its geometry, which enables it to increase the membrane density in a fixed tank area. In the Zuidhorn case, membrane density was increased from 24 to 63 percent using Sanitaire Gold Series diffusers. This allowed the flux to be reduced, resulting in higher Standard Oxygen Transfer Efficiency (SOTE), which, in turn, delivered improved Standard Aeration Efficiency (SAE).
“The Sanitaire Gold system is unlike any other on the market today, with its combination of reduced energy consumption and its modular design that is easy to install, maintain and scale,” says Annita Nerses, Director/General Manager for Biological Treatment. “Thanks to its time-proven components and piping system design, it offers long-term reliability that has won the confidence of treatment plant operators around the world.”