Displaying items by tag: wastewater
Global tissue products company SCA is achieving savings following a blower-technology switch at the wastewater treatment plant serving its Oakenholt Mill in north Wales.
SCA had experienced reliability issues with the two existing lobe-type blowers at the 70-employee site near Flint, which produces tissues and paper towels. The units were used in the energy-intensive process of supplying aeration air to the wastewater treatment plant.
Aeration blowers can represent up to 70% of the electricity costs as a wastewater treatment plant due to the large quantities of air that needed to be blown into the aeration tanks.
In view of these requirements, SCA area engineering leader Paul Blundell selected Atlas Copco’s ZS+ range of oil-free positive displacement screw blower. These models are designed to be on average 30% more energy-efficient than conventional lobe-type, low-pressure alternatives.
The blower installed by SCA was a ZS37+ VSD-800 dry, oil-free rotary screw displacement blower unit – design incorporating precision timing gears. These maintain minute clearances between two intermeshing dry screw elements that never touch.
No lubrication is required in the compression space and special seals stop any rotor bearing oil from entering the compression chamber. Intake air is compressed between the rotors and their housing and oil-free, pulsation-free air at a pressure of 800mbar is delivered at an output rate of between 284 -947m3h.
The VSD version of the blower chosen by SCA was fitted with Atlas Copco’s Elektronikon operating system. This is designed to monitor overall system performance and increase efficiency and reliability by directly controlling the blower’s speed to the level of dissolved oxygen in the water.
According to Blundell, the blower has exceeded expectations in terms of energy savings and has run almost continuously for a year at 30-50% load. An Atlas Copco air network audit and survey system. he added, had made it possible to link the blower facility to the site’s building management system.
"This allows condition and service requirements to be fed directly to Atlas Copco’s service department either by mobile phone or via the internet,” said Blundell, who is now considering replacing the remaining lobe-type blower with another ZS+.