Skip to main content


Buy Article:

$9.50 plus tax (Refund Policy)

Or sign up for a free trial

Two large scale projects have been successfully brought on line utilising the thermal pre-treatment to ensure production of a Class A biosolid product. In Reading (UK), the sludge is pasteurised prior to mesophilic anaerobic digestion while in Dublin (Ireland), the sludge is both pasteurised and hydrolysed prior to digestion.

Sludge is pasteurised by holding a batch of sludge at 70°C (158°C) for greater than 30 minutes. Sludge is pasteurised and hydrolysed thermally by holding a batch at 165°C (329°F) for 24 minutes at 6 bar pressure. The combination of the high temperature during the cycle and the pressure drop at the end of the cycle breaks open cells making the sludge more readily biodegradable.

Sludge pasteurisation was chosen for Reading to achieve a Class A product and to minimise sludge storage (holding) times on a plant in a sensitive area. We expected improved volatile destruction and dewatering but to date have seen no evidence of either of these.

Thermal Hydrolysis (TH) was chosen for Dublin to minimise the amount of sludge that had to be dried and to reduce the size of the anaerobic digesters.

The purpose of this paper is to compare the two approaches. Both systems use batch reactors to treat the sludge and both systems control the digester temperature.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Data/Media
No Metrics

Document Type: Research Article

Publication date: 2005-01-01

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • Learn about the many other WEF member benefits and join today
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more