Flygt Mixers Reduce Energy Consumption by 65%
Xylem, a leading water technology and pump company, recently claimed that their pumps enabled an Italian wastewater treatment plant to reduce its energy consumption by 65%.
The pump manufacturer’s claim is substantiated by a comparison study conducted by Comopedur, the company that operates the plant. Located in the Lake Como area of Northern Italy, the plant treats 16 million cubed meters of wastewater annually, serving a population of 200,000. Due to the plant’s location in a dense area of the city, it is difficult to access with heavy machinery. After treatment, the water from the plant is expelled back into Lake Como.
Comopedur was interested if operation costs at the plant could be reduced, and commissioned Xylem to give a recommendation. At the time, five mixers had been in operation in the pre-dentrification tank for ten years. The 5,800 cubic meter tank is a particular shape that required multiple mixers and a high level of energy to operate. “Dead spots”, tank depth and irregular slopes proved a challenge for consistent mixing, though the five mixers performed reliably in the ten years they were installed.
Xylem examined the system and used simulation software to determine the best solution for Comopedur. After a thorough examination, the company advised replacing the existing mixers with the new, mid-size energy efficient Flygt 4530 model. This model is specifically designed for biological wastewater treatment applications and features a 1.2 diameter propeller.
The new mixers were a resounding success at the wastewater plant, consuming 175,000 kWh of energy annually, a 65% reduction on the 500,000 kWh the old mixers required to operate. This translates to an annual savings of €50,000 (USD $69,335). Luigi Cece, Director of the Comopedur plant, says “they paid for themselves within just 13 months.”
Since the proven efficiency and effectiveness of the Flygt 4530 mixers in the pre-dentrification tank, Comopedur has ordered three additional mixers for another equalization tank within the wastewater treatment plant.