With Veolia’s help, Scottish Water strives to realise energy self-sufficiency

Veolia, the global resource management company, is now helping Scottish Water to achieve the target of energy self-sufficiency at its Seafield Wastewater Treatment Works (WwTW), the largest treatment works in the east of Scotland. 

Since 2015, Veolia have extended the site’s capability to generate its own energy from 55 per cent to around 85 per cent in 2017 by boosting the renewable energy derived from a combination anaerobic digestion of sludge and biogas fired combined heat and power (CHP) plants. In fact, full self-sufficiency had already been achieved at various points in 2017 when Seafield used no electricity from the Grid.

Seafield WwTW treats around 300 million litres of wastewater every day for approximately 850,000 people from Edinburgh and the surrounding area. But by implementing a range of innovations and increasing efficiency, the target of energy self-sufficiency has become a practical target and will further the utility’s efforts towards sustainability and lower carbon emissions.

The advances to date mean that the Seafield site has also reduced its energy costs by 50 per cent – which will help meet the value-for- money consumer criteria set for the industry. Presently, the water industry is the fourth most energy-intensive industry in the United Kingdom (U.K.), using an estimated 3 per cent of electricity for pumping, water treatment, and waste management, also contributing around 1 per cent of the nation’s greenhouse gas (GHG) emissions.

Working in partnership with Scottish Water, Veolia has introduced a wide range of measures to derive renewable energy using sludge as a valuable resource. Measures installed to date include a thermal hydrolysis process that has increased biogas production by around 10 per cent, investment in an additional CHP unit to provide greater energy generation and to take advantage of the additional biogas, and a further 3 per cent increase in the yield of biogas.

“Recent estimates indicate that the water industry could be self-sustaining for electricity by harnessing the 11 billion litre annual flow of wastewater,” John Abraham, Chief Operating Officer Water at Veolia, said. “Our application of technology to this process demonstrates how we can help deliver greater sustainability for the industry using waste water to energy systems, and also meet water industry carbon reduction targets. In this way we can make a significant contribution towards delivering renewable energy targets, while keeping the lights on and taking pressure from the National Grid.”