Supply, Delivery & Commission of a Thermal Hydrolysis Process (THP) System at Netheridge STW

Severn Trent Water (STW) serves over eight million people in the heart of the UK, supplying nearly

over eight million people in the heart of the UK, supplying nearly two billion litres of drinking

water a day to the highest standards in Europe. STW takes away used water, treats it at over 1,000 sewage works and puts it safely back into rivers and streams.

Bioresources within STW operates currently 25 sludge treatment facilities across the whole STW region. These treatment facilities process 260,000 tonnes of dry solids produced by the wastewater treatment process.

STW is required to treat and safely dispose of this material as part of our undertaking. All sludge treatment facilities use anaerobic digestion to convert organic matter from sludge into renewable energy and biosolids.

In order to enhance our capacity to treat sludge and meet sludge volume increases in the most efficient way, STW intends to procure a Thermal Hydraulic Process (THP) system for the treatment of surplus sludge from our site at Netheridge. Netheridge is STW's largest treatment works in the south region. It is located to the south of Gloucester and is bounded by the River Severn to the west and the Gloucester & Sharpness Canal to the east. The site can treat up to 42.8ml a day (dry weather flow) and currently serves a population of roughly 200k. At current processing rates, sludge processing in the region is due to hit capacity by 2030, which is one of the key drivers for this upgrade.

STW intends to procure a thermal hydrolysis process (THP) solution meeting the following requirements for Netheridge:

• Have a minimum design life of 20 years
• Be designed for average sludge composition in feed to the thermal hydrolysis system, which is anticipated to be 37% primary sludge, 63% secondary sludge.
• Be able to cope with Annual Design Solids load to hydrolysis system of 16,081 tDS/year
• Be able to cope with Peak daily sludge load to hydrolysis system of 51.0 tDS/d
• The thermal hydrolysis process shall achieve a minimum 6-log kill of indicator organisms (E coli).
• The design of the hydrolysis process shall include for energy recovery systems so as to minimise energy consumption where practicable.

The scope of this procurement is expected to include:

• Supply of appropriate THP solution for Netheridge
• Delivery (Delivery of the units is required on site by early 2027)
• Installation / Installation support (complete by mid 2027)
• Commissioning (complete by end 2027)
• Operator Training
• Maintenance provisions

The THP will have to comply with all relevant Statutory Regulations (DSEAR, PSR, PSSR, PUWER and all UK and Harmonised EU suite of regs.) as well as all relevant STW Specifications and Design Manual requirements unless exemptions are sought and instructed.

The supplier for the THPs will need to liaise with both STW and STW's nominated contractor for the site to collaborate with regards to site specific requirements, supporting the programme timeline, asset installation and commissioning.

If you are interested in this opportunity and capable of meeting the requirements set out in the scope, please email [email protected] with copy to [email protected] by 15th June 2025, 17:00 hours (BST), setting out your company details and providing a case study of your technology's successful installation and operation on a sewage treatment plant.