Waste Water Could Heat Scottish Cities, Study Claims
Published by Water Network Research, Official research team of The Water Network in Academic
Scotland’s sewers could contain enough natural heat to warm Glasgow for more than 15 years.
The claim comes in a study carried out by Scottish Water Horizons for Scottish Renewables, which shows how renewable energy technology like heat pumps could be used to harness that energy potential.
Waste water treatment plant. Photo credit: Scottish Water Horizons
Scottish Water Horizon’s business development manager Donald MacBrayne said: “Water that is flushed down the drain from homes and businesses represents a significant source of thermal energy.
“Usually, this heat is lost during the treatment process and when treated effluent is returned to the environment. By tapping into this resource using heat recovery technology we can provide a sustainable heating solution which brings both cost, carbon and wider environmental benefits.”
The study found that 921 million litres of wastewater and sewage is flushed down Scots toilets and plugholes every day.
The researchers found that by capturing the warmth over 10,000 tonnes of CO2 could be prevented from entering the atmosphere.
Water in UK sewers can reach temperatures of 21 degrees celcius and maintains a constant temperature throughout the year.
Scottish Renewables policy manager Stephanie Clark said: “These new figures show the enormous scale of the energy we are literally flushing away every day.
Read more: Energy Voice
Tags
Category: Academic
- Treatment
- Sewage Treatment
- Treatment Plants
- Industrial Water Reuse
- Integrated Water Management
- Reuse
- Sustainability
- Water-Energy Nexus
- Energy Efficiency
- Integrated Infrastructure
1 Comment
Sorry, but this doesn't make sense to me. In the first instance, every wastewater treatment plant operator and process designer knows that wastewater temperatures vary throughout the year. In the UK the range is typically 10-22°C and colder in Scotland (not a constant 21°C as reported).
Second, if you use wastewater as a source for a heat pump, you cool the wastewater. All biological processes such as nitrification (the oxidation of ammonia) are temperature-sensitive so they won't work as well (if at all) during winter. The result will be polluted rivers or a massive spend to build larger treatment works.
Third, a daily flow of 921 million litres per day (that's ALL the wastewater in Scotland), cooled from 10°C to 5°C at 100% efficiency (impossible!) Would yield about 50MW of power. I know the Scots are a hardy bunch but I think even they would want a bit more than 50 MW to heat a city in a Scottish winter.
Energy recovery from wastewater has its place, but let's be realistic about it rather than trying to create fanciful headline-grabbing stories.
Published by Jeremy Biddle, Engineering Director at Bluewater Bio