Published: 28 augustus 2017 10:13
Published: 28 augustus 2017 10:13
Source: The Guardian
Date: July 27, 2017
A pilot scheme in the Netherlands is sifting sewage for cellulose, which it says can be recycled into valuable products
When you flush the toilet, you’re probably not thinking about bike lanes or home insulation. But that’s where your used loo roll could one day end up if a Dutch project to extract cellulose from sewage rolls out.
At the Geestmerambacht wastewater treatment plant near Alkmaar in the Netherlands, a two-year pilot project is using an industrial sieve to sift 400kg of cellulose, the natural fibres found in loo roll, from toilet sludge each day.
The cellulose, which would otherwise be incinerated at the end of the sewage treatment process, is cleaned and sterilised with very high temperatures and turned into a fluffy material or pellets. These are sold on as a raw material for products like asphalt and building materials.
A portion is also exported to the UK, where Brunel University is working on technology to transform it into an energy source, bioplastic bottles and other products.
The Dutch preference for luxury loo roll means the cellulose is of premium quality, says Carlijn Lahaye, managing director of CirTec, one of two companies behind the Cellvation project, which launched in June with help from an EU grant. “In the Netherlands, a lot of paper flushes through the toilet and it’s a high-quality fibre,” she says.
It’s one of several reasons Lahaye is convinced by the business case for recycling used loo paper. Although the quantities of cellulose processed by the pilot are currently too low to be profitable the basic model is sound, she says. “You remove something that costs energy to pump around, lower the operational cost, there’s more space to treat water and you get money for something that would be burnt as waste.”
The Dutch flush away 180,000 tonnes of paper each year, according to the country’s water authorities. And they are not alone in their profligacy: the European Tissue Symposium estimates that Europe used five million tonnes of toilet paper last year.
The cost – and opportunity – of this has long been clear to the Netherlands’ 25 water authorities, says Noor Ney, head of sanitation with the Hollands Noorderkwartier (HHNK) water board, which for eight years has been referring to treatment plants as “energy and resource factories”, she adds.
The Cellvation project is just one of many schemes around the country attempting to extract value from sewage, says Ney. Another company, AquaMinerals, works with various water providers to produce calcite pellets from wastewater, which can then be reused for softening water, or for products like ceramics and paint.
“[Sewage] isn’t only waste: it is a carrier of valuable resources: phosphates, cellulose, energy and clean water,” says Ney. “We act as a facilitator, allowing [a] company to see how far it gets on one of our plants. If it is able to extract a product that has value, then our process to clean water becomes cheaper.”
Loo roll alternatives
Not everyone is convinced that recycling loo roll makes sense, however, given the energy and financial investment required for extracting and sterilising it.
Sarah Bell, senior lecturer in environmental engineering at UCL says a full life cycle assessment would be needed to know “if the overall benefits of recycing the cellulose outweigh the impacts of the recycling process itself.”
There could also be opportunity costs, she says: “Recovering the cellulose from the sludge … could reduce the energy content of the sludge, which would undermine its value as a bioenergy source.”
Rather than spending so much time, money and energy recycling toilet paper, should we simply be curbing its use?
Singer Sheryl Crow famously urged people to use just one square a visit to help protect the planet. But there are other options too. Helen Rankin, managing director of Cheeky Wipes, sells reusable fabric toilet paper, known as ‘family cloth’, which she also uses at home.
“We have a bin in each bathroom and a couple of times a week chuck them in a long, hot wash,” she says. “It is a niche market and a lot of people are grossed out about it, but compared with cloth nappies, it’s nothing.
In many countries, water is already the main way of getting clean after a loo visit. In Thailand for example, toilets tend to come with a hose and Japan’s all-singing, all-dancing toilet seats include nozzles for spraying water. Even in the UK, where the French bidet never really thrived, loos with in-built washing systems are now widely available to buy.
But persuading people to ditch toilet paper is tricky, says professor Mizi Fan of Brunel University London, a research partner on the Dutch project. “It is not easy to change this sort of habit,” he says. “Toilet paper utilisation does vary from country to country, but… there is a link to a perception of hygiene.”
Could that link also hamper efforts to recycle toilet paper into consumer products? John Bissell, chief executive of start-up Origin Materials, which has worked on a project to turn sewage sludge into plastic bottles, admits there is an ick factor: “Consumers have a perception problem dealing with the sewage aspect,” he says.