Potato grown with human urine: ‘Cleaner than animal manure’

• Cas Berg’s

  domestic editor

Today, the first potatoes fertilized with human urine are being harvested in a test field at Wageningen University in Lelystad. The university wants to find a sustainable alternative to animal manure and artificial fertilizers, so it is testing new fertilizers.

It might sound silly, but project leader Kimo van Dijk from Wageningen University sees it differently. “Now we also use manure from animals, manure from ourselves is not much different. “

The aim of the experiment is to see how human waste streams, including urine, dirt and sewage, can be used to grow crops. According to Van Dijk, domestic wastewater often contains nutrients that are lost when they end up in the sewer.

“That’s a shame, we currently import a lot of nutrients for agriculture in the Netherlands in the form of animal feed and fertilizers,” says the project director. “Although many of these materials can be recovered from We have waste water.”

“We currently use a lot of fertilizers in agriculture to add extra nutrients like phosphate,” says Van Dijk. That’s a lot of pollution.

Phosphate is often extracted from mines overseas. “It’s pollution brought in and it is also a fossil material that will eventually run out. With this test we hope to offer a sustainable alternative.” Because, according to Van Dijk, it is easy to remove phosphate from human feces.

The test also tests other waste water streams, such as water from the food industry. “Factories that handle potatoes rinse the mud from the crop and wash the peels,” says Van Dijk. “The water that’s left also contains nutrients. These are now not allowed to be scattered over the earth.”

In addition, sludge from the public sewer is also used in the experiment. This is a type of clay made from waste materials that are usually burned.

The urine for the test was collected in a residential group in Arnhem. “We have toilets where the urine is separated and goes into a tank. ” According to the researcher, this is also necessary, because in regular toilets the urine is diluted with water, making it unsuitable for extracting nutrients.

Van Dijk hopes that more households will collect their feces in the future. “It’s a big move and it takes effort. ” He believes that there is potential to remove these materials from new houses.

Potato grower and LTO board member Pieter Evenhuis is also enthusiastic about the lawsuit. “Usually there’s a gap in the round, which is the human,” he says. “That’s why it’s great that they’re now trying to close that by – used nutrition.”

The potato grower is not completely unconcerned. “The danger of using substances from the sewer is that you don’t know exactly what’s in it. For example, you don’t want substances from medicines that haven’t broken down yet to finish the land.”

Scientist Van Dijk believes this is a reasonable concern. “We looked at the contents of all the fertilizers in the test and compared that with what Dutch fertilizers might contain at the moment. After filtering, we check whether there are any medicinal residues or pathogens remaining. These are then removed by two additional filtering steps.”

Laughing, he says: “I’d like to say that our urine concentrate is cleaner than normal animal manure, and it doesn’t smell as bad either.”