Seafield Waste Water Treatment Works

Seafield WwTW

Update 24th April:

The storm tank cleaning has been successfully completed by Veolia.

Update 22 April:

At the end of March we updated stakeholders on tank cleaning activities at Seafield.  Work within the storm tanks was called to a halt after two of the four tanks had been drained and cleaned.  The residual material was left insitu and covered with treated final effluent.  Following a reassessment of the plant operating conditions and associated mitigation measures, the storm tank cleaning will recommence on Thursday 23rd April.  Every effort will be made to complete this work as quickly as possible and to minimise odour, with odour reducing additives being deployed as necessary. 


Update 16 April: 

We have received an increase in odour complaints in the Seafield area recently and Scottish Water and Veolia apologise for this. 

Veolia began essential maintenance of the storm tanks at Seafield WWTW at the start of the current lockdown period. This work was paused as a result of a change in weather conditions and, in consultation with regulators, it was agreed that it would be sensible to complete the remaining essential maintenance at the earliest opportunity.

In order to mitigate the odour risk that continues until this maintenance is complete, we will take further operational measures over the coming days – including using chemical dosing – in order to help minimise the issue.

Please be assured we will have this resolved as quickly as possible and we will update stakeholders when this work will be carried out and completed. We thank our customers for their patience.


Update 27 March 2020:

Yesterday afternoon we updated this page regarding tank cleaning activities at Seafield and we can confirm that the operations have ended.  We appreciate that odour associated with these works has coincided with north-easterly wind direction during part of the works which caused annoyance in the community. On behalf of Scottish Water and Veolia, we would like to apologise.  Scottish Water and Veolia are working hard to maintain essential wastewater service delivery at this time but I would like to assure you that odour management remains a key consideration in work planning and resourcing.


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 Green Energy Video

Watch this video to see how we are making Seafield waste water treatment works in Edinburgh greener and more self-sufficient.