Scotland’s largest waste water treatment works at Seafield which processes 300 million litres of waste water every day is this month celebrating its 40th anniversary.

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.

The works 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.

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 plant is capable of producing up to 2300 kilowatts of sustainable electricity. Offset, this is 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 ‘green’ power.

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

A Veolia spokesman commented:

“The challenge for the next decade will be to move towards energy self-sufficiency, cut carbon and exploit all the opportunities for customer-controlled energy. Harnessing the potential of seven million tonnes of human waste each year will become a vital strategy to meeting these challenges.

“Anaerobic Digestion and Combined Heat and Power technology is advancing rapidly, with gas cleaning systems, lean-burn engine-based CHPs and thermal hydrolysis already creating the potential to double renewable generation capacity by 1,697 gigawatt hours – enough to power half a million homes.”