WPL Hybrid-SAF Hired for AMP 6 Project


Mott MacDonald Bentley hires a hybrid packaged sewage treatment plant for Carlton Husthwaite wastewater treatment works. The hire plant consists of the new WPL Hybrid SAF tank (made from GRP and steel exoskeleton) and humus final settlement tank for the Yorkshire Water AMP 6 project.

The 170 population equivalent site has retained the primary settlement tank, and the hire plant replaces the original Rotating Biological Contactor (RBC) until the permanent WPL HiPAF  (below ground) solution is installed in Q3.

Andrew Haywood, Utility and Industrial Sales Manager states “WPL provided a solution to allow the existing RBC to be taken offline whilst maintaining treatment. We have worked close with Mott McDonald Bentley to provide a permanent solution designed strictly in accordance with the Yorkshire Water SAF specification.”

The permanent bespoke HiPAF will consist of a SAF and filter humus (section) packaged treatment plant to work with the current primary settlement tank.

The bespoke WPL HiPAF Features include:

  • Mk.3 lids with high level safety grids throughout the plant which provides superior access to all parts of the units for maintenance, enhanced operation and safety.
  • Stainless steel internal aeration pipework.
  • Fixed drain down facility with bauer connector.
  • Process design accordance with the Yorkshire Water SAF specification.
  • Acoustic lined GRP XL Kiosk complete with vent fan and cowl to house the energy efficient duty stand-by air blowers and manifold.

Site Effluent Discharge Standard (95%ile based on spot samples):

  •  BOD5 (ATU) – Descriptive
  • Suspended Solids – Descriptive
  • Ammonia – Descriptive

Carlton Husthwaite WwTw


WPL Hybrid SAF (left) and Humus Settlement Tank (right)

About the WPL Hybrid-SAF

The Hybrid SAF is unique to WPL, made from a robust glass-reinforced plastic (GRP) tank with galvanised structural steel ‘exoskeleton’. The GRP is UV stabilised with an external gel coat finish which extends the asset life to a minimum of 25 years – UK water industry standard requirement.

Modular in design the Hybrid SAF allows ease-of-access to height- or width-restricted sites, while the low weight of each unit means it can be delivered and off-loaded with a Hiab crane. This removes the need for large lifting equipment onsite during installation and reduces delivery costs.

Why the WPL SAF

WPL’s robust biological treatment process is backed by proven WPL SAF technology based on 25 years empirical data offering treatment for carbonaceous (BOD) removal, nitrification and de-nitrification (Total N) when strict standards are required.