UK water utility's energy, costs to be reduced with screw blower technology

Sponsored by

Sept. 24, 2013 -- Energy consumption and service costs at Northumbrian Water's sewage treatment works in Newton Aycliffe, County Durham, UK, will be reduced with the company's decision to adopt Atlas Copco's screw blower technology.

Northumbrian Water, a leading provider of water and sewerage services in the North East of England, which has been awarded the 'Queens Award for Enterprise: Sustainable Development' and 'Water Company of the Year' previously, needs a constant, reliable supply of air in the region of 480mbar for aerobic treatment of wastewater at its site in Newton Aycliffe. This process uses bacteria to break up waste particles and requires large amounts of air to be blown into the aeration tanks to maintain the desired level of dissolved oxygen within the wastewater containment system -- a biological process that typically utilizes up to 70 percent of the energy consumed on site.

There is a changing perspective within the water industry that the widely-used lobe blower design principle no longer meets the needs of today's low carbon economy and that operators can benefit substantially from energy savings through the replacement of conventional lobe equipment with innovative screw technology.

Northumbrian Water site


Such was the experience of Northumbrian Water, whose aeration air supply was originally delivered to the site by four lobe type blowers. However, when one of these units started to develop reliability issues, the opportunity was taken to investigate the possibility of installing one of the new generation of high-efficiency screw type blowers which, compared to standard lobe type machines, offer potential savings of up to 30 percent in energy consumption.

Northumbrian Water decided to replace one lobe blower with the Atlas Copco ZS screw blower technology. On completion of the installation of the new ZS blower, Northumbrian Water carried out a comparison performance test between the existing lobe blowers and Atlas Copco's ZS technology. Data from air flow meters and power monitors was put into the site's PLC/SCADA system to calculate the specific power of all four air blowers. The calculated values of air production were averaged over a 12-hour period. In order to compare like for like, the ZS unit was compared with the performance of the other blowers at the same time on the following or preceding days during similar weather, flow and biological load conditions. It revealed that the existing lobe blower used approximately 19 percent more power for the same output.

ZS blower


Based on these test results and continuous reliability issues with the lobe blowers, it was decided to replace a second lobe blower with an Atlas Copco ZS90-VSD, low-pressure, oil-free rotary screw blower. The blower unit comprises a complete package based on a simple internal principle: precision timing gears maintain minute clearances between two intermeshing dry screw elements that never touch. No lubrication is required in the compression space, and specially-designed seals prevent 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 pressures of approx. 480 mbar is delivered at an output rate of more than 4000m3/hr. dependent upon process demand.

Energy savings are derived from the efficiency of the internal compression screw design and the direct drive, integrated gearbox that ensures fewer losses compared to the traditional belt and pulley system. For example, to deliver a flow of 1600 m³/hr. (942 cfm) at a pressure of 0.8 bar (e) (11.6 psig), a tri-lobe blower consumes 61 kW (82 hp) on average. By comparison, the screw blower consumes only 43 kW (58 hp) to match this performance. At the same time reliability has been improved and maintenance costs reduced.

Northumbrian Water has now placed a third order with Atlas Copco to replace the remaining two lobe units installed at Newton Aycliffe Waste Water Treatment Plant with a further two ZS 90 screw blowers.

###

 

Sponsored by

TODAY'S HEADLINES

EPA awards over $17M in Great Lakes Restoration Initiative grants to address algal blooms

The Environmental Protection Agency has announced the award of 14 Great Lakes Restoration Initiative grants totaling over $17 million to fund projects that will improve Great Lakes water quality by preventing phosphorus runoff and soil erosion that contribute to algal blooms.

Texas water district recognized for Eagle Mountain Spillway Dam rehabilitation

The Association of State Dam Safety Officials announced that it has awarded the Tarrant Regional Water District of Texas with the National Rehabilitation Project of the Year Award.

Innovyze named winner of prestigious Esri Partner Conference Award

Innovyze recently announced that it was named the winner of the ArcGIS for Desktop Based Application category of the Esri Partner Conference Awards.

CH2M HILL partnership to deliver safe, clean water supply to Jaipur, India

CH2M HILL in partnership with the Singapore Public Utilities Board and Singapore Cooperation Enterprise, is providing water management leadership services to the Rajasthan state government through Public Health and Environment Department for the city of Jaipur, India.

FOLLOW US ON SOCIAL MEDIA