More sustainable sludge digestion helps water companies become more sustainable

Every wastewater treatment plant produces sludge. Wet biowaste treatment is difficult and that makes it an expensive joke for water companies. According to RoyalHaskoningDHV, it can even reach 70 percent of operating costs for some companies. Anglian Water’s hydrolysis technology reduces these costs and ensures a lower CO2 footprint.

Mud problem

Worldwide, nearly 6 billion tonnes of sludge are produced annually, for example in the form of sewage sludge or manure. There is no good way to treat wet biowaste for a long time. That’s why (and in some places in the world: is) it gets dumped in a landfill, for example, and it’s far from ideal. This is because the sludge can ferment there, releasing a lot of methane. And methane contributes about 25 times more to climate change than CO2.

Another method that is often used to remove sludge is combustion. But that’s not a good solution either. Sludge is made up of about 80 percent water, which makes its combustion extremely energy efficient.

More biogas

But the sludge can also be used for biogas production, by fermentation. More and more water companies are working with this, for example at the sewage treatment plant in Nieuwegein. Anglian Water has a method to maximize biogas production from sludge. British water companies are already implementing this so-called hph technology in four locations. According to the company, biogas production at this location is 12.5 percent higher than the location with a conventional digester.

Anglian Waters improves the remaining sludge into high quality raw materials that can be used as soil improvers in agriculture.

Rebecca Burke

"Coffee trailblazer. Analyst. General music geek. Bacon maven. Devoted organizer. Incurable internet ninja. Entrepreneur."

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