Huddersfield ERF - OCU Case Study

Greenacre Environmental Systems Limited was engaged by the client to undertake the provision of the ventilation extraction and odour control systems upgrade at the formerly Calder Valley Sewage Treatment site. The project was part of a larger scheme to upgrade the sewage treatment facility, transforming the site into the Huddersfield Energy and Recycling Facility.


  • Ventilation extraction and odour control systems for both the cake import and the sludge thickening processes to mitigate DSEAR risk, COSHH risk and to provide odour control.
  • Local control panel providing key equipment parameters to SCADA such as low airflow.
  • The sludge thickening OCU extracts contaminated and odours air from the drum thickeners, thickend liquors PS and digester feed tanks. There are 2 stages of odour treatment; 1 single bed, counter current, trickling biofilter and single bed activated carbon absorber polishing unit.
  • A 15m exhaust stack with bespoke support structure along with access steelwork for maintenance of the bio filter spray nozzles
  • Two ATEX rated centrifugal exhaust fans arranged in a duty and standby configuration.
  • Commissioning including airflow balancing, odour monitoring and olfactometry tests over a period of 7 days confirming the odour control equipment effectiveness.