Seafield Waste Water Treatment Works

Seafield WwTW


Seafield is Scotland’s largest waste water treatment works (WWTW) which processes 300 million litres of waste water every day – enough to fill 121 Olympic-sized swimming pools. 

The site is a hugely important part of Scotland’s infrastructure and is critical to keeping the cycle flowing in Edinburgh and the wider Lothians serving almost one million people.

Since 2011 Scottish Water and Veolia have invested £34 million into Seafield, installing new equipment to improve odour as well as a thermal hydrolysis plant which treats and pasteurises the raw sewage, generating biogas energy which provides 85% of Seafield’s electricity.

The sewage is then turned into sludge cake and sold to farmers as organic fertiliser. This process makes it one of the greenest waste water treatment plants in the UK.

The site is one of the most modern and environmentally-friendly of its kind using a Combined Heat and Power plant and Thermal Hydrolysis to generate electricity and treat the waste for agricultural use. Over the last four decades it has been transformed from a much smaller site - which treated and separated waste water from untreated sewage disposed of in the Forth via the MV Gardyloo ship.

The plant is capable of producing up to 2300 kilowatts of sustainable electricity - enough to power up to 600 homes. This is produced by gas powered generators which use the gas produced in the 6 digesters on site to generate this ‘green’ power.

A multi-million pounds Odour Improvement Plan was completed in 2012 and the facility is now continually monitored for any potential odour issues.

The works has a strict monitoring regime overseen by a number of environmental regulators. Local community groups and politicians attend regular stakeholder meetings with staff from Scottish Water and Veolia where they are updated on developments at the site. 

Click here for all stakeholder updates and related documents

Seafield Investment Leaflet

Information about our investment in Seafield from now until 2025

Download Leaflet