Hot Topic: Biogas & The UK Water Industry SWS Blog

The water industry in the UK could make resources more affordable and companies more self-sufficient if anaerobic digestion and the conversion of sewage to energy is given greater focus in the future.

The naturally-occurring process of turning waste into energy is known as anaerobic digestion and the use of anaerobic digesters has been around since at least the Victorian times, initially developed to prevent the buildup of sewage and stop the spread of disease.

Interestingly, it’s thought that the first human use of biogas can be dated all the way back to 3,000 BC and the Middle East, where the Assyrians used it to heat their baths.

The first large anaerobic digestion plant can be traced to a leper colony in Bombay in 1859. And over in London, John Webb – a Victorian engineer – came up with the idea of the Sewage Lamp, which turned sewage into biogas to light street lamps. You can, in fact, find London’s only remaining Web Sewer Lamp in Carting Lane, just off The Strand!

And now, 100 years after the Victorian age, this technology is still essentially the same, although improvements and efficiencies have of course been made, with water firms increasingly starting to use sludge to generate biogas, which can then be used to generate green power, making the country’s electricity supply cleaner and more resilient at peak times.

Speaking to the Financial Times, chief executive of Global Water Intelligence Christopher Gasson explained that the biogas process could, in fact, be a game-changer for the water sector, since water and wastewater utilities use huge amounts of power, consuming approximately 3.7 per cent of global annual energy.

But by making more effective use of waste, economic and environmental benefits could be combined, he explained, adding: “Most low and middle-income countries can’t afford to treat wastewater despite its impact on the environment and public health.

“Biogas production could transform the economics of good sanitation and deliver a huge net benefit in terms of greenhouse gas emissions.”

Water regulator Ofwat has been supporting the transition to biogas production, providing financial incentives to drive adoption of thermal hydrolysis plants, the technology of which is being sold by Norwegian company Cambi.

These plants apply pressure and high temperatures to sewage sludge and wet organic waste to produce even greater quantities of gas than traditional anaerobic digestion plants.

While Cambi plants can be found all over the world, the firm’s biggest market thus far is the UK, with Ofwat also bringing in measures to encourage trading in sludge between suppliers so that economies of scale can be produced.

As well as the 25 Cambi plants on UK shores, figures from trade body Water UK show that the 17 large water and sewerage firms around the country have increased biomethane production in the UK, up from 382GW hours to 477GW hours – which is enough to provide power for 40,000 homes.

Biogas: What are water suppliers doing?

The good news is that water suppliers all around the UK are now increasingly turning to biogas as an option for green power generation.

Earlier this year, for example, Thames Water announced a £7.3 million scheme to use biogas generated during the sewage treatment process at its Deephams plant, which will save thousands of tonnes of CO2 from entering the atmosphere each year.

It has also partnered with the University of Surrey to perfect the anaerobic digestion process at peak times of day, with the hope being that the new science will be adopted across the entire industry. If fully implemented, it will make the UK’s electricity supply cleaner and more resilient at peak times – which is when customers need it the most.

Scottish Water, meanwhile, uses anaerobic digestion technology to generate clean green energy at its Deerdykes Recycling Centre near Cumbernauld. The facility can handle 30,000 tonnes of food waste and generates up to 8GWh of renewable energy annually, which is enough electricity to power approximately 2,400 homes.

And last year, Yorkshire Water treated and recycled 147,500 dry tonnes of sewage sludge, with the plan being to use all its sludge to produce renewable energy.

It will certainly be interesting to see what happens with biogas and the water industry in the future. We’ll be keeping our eye on developments and will post about them here as and when they happen. And don’t forget – if you need help finding your water supplier, get in touch with the team here at SwitchWaterSupplier.com and we can guide you through the process.