SBAP Sludge Strategy Davyhulme

One of the largest Thermal Hydrolysis Facilities in the world that will reduce UU’s CO2 emissions by 1.4 million tonnes over the next 30 years

Manchester, UK

Introduction

MWH, now part of Stantec, supported United Utilities in developing the Sludge Balanced Asset Programme at Davyhulme Wastewater Treatment Works in Manchester, UK. This innovative solution produces a sustainable, low carbon process that increases United Utilities’ options for biosolids disposal routes, while maximising energy recovery from biosolids and minimising project carbon footprint. It is one of the largest Thermal Hydrolysis Facilities in the world, converting sewage sludge into renewable electricity using the thermal hydrolysis process.

Scope

Enabling works include the upgrade of sludge screening and loading equipment at 7 satellite sites. Transport of dewatered sludge from satellite sites to a purpose-built 91,000 tDS/year processing centre. Advanced digestion by thermal hydrolysis to meet enhanced (Class A) product for disposal to agricultural land. Co-generation, with Biogas cleaning for enhanced CHP engine efficiency. Up to 32,000 tDS/year of the sludge recycled to land as a Class A cake product. The remainder of sludge is pumped to the MVPC for EFW generation.

SBAP Sludge Strategy Davyhulme

Challenges

A key aim of MWH was to determine the most cost effective solution to satisfy the expectations of neighbouring residents and business, which did not expose the client to undue levels of risk. It was also MWH’s focus to construct the plant with minimal disruption to site operations and within a very tight schedule.

Solution

MWH assessed the greenhouse gas emissions associated with construction and future operation of two alternative sludge processing options for Lancashire, UK. The total carbon generation was calculated using Defra’s guidance on shadow pricing, including carbon from chemical production and transport, emissions associated with energy use and transport of sludge and waste. This was used to support a revised proposal to the economic regulator to change the solution from raw Energy from Waste treatment to advanced sludge digestion, with its lower carbon footprint.

The SBAP at Davyhulme Wastewater Treatment Works was awarded The Major Civil Engineering Project of the Year at the British Construction Industry Awards 2014 and Large Civil Engineering Project of the Year at the ICE North West Awards 2015.

Images accredited to United Utilities.

Davyhulme Wastewater Treatment Works