From pig poop to rainwater: Flemish farmer bursts onto circular economy scene


A family farm in West Flanders is turning its livestock’s waste into irrigation water for itself and several of its neighbours – solving two problems at once

First of its kind

The idea came to Johny Verhelst in December of 2018. A West Flemish bioengineer and second-generation farmer, he realised that paying others to process the manure of the 6,000 pigs on their two farms was a big cost to the family-owned company.

So the 27-year-old set out to build his own manure-processing plant in Langemark, one that would be able to transform the pig waste into water that could be used to irrigate farmlands. The installation he devised – the only one of its kind in Flanders – has the potential to solve two of the biggest problems farmers around the world are running into at the moment: summer-time water shortages and manure surplus.

Due to increasingly strict environmental rules, farmers can no longer dump livestock manure on their farmlands like they used to. At the same time, provincial governors in Flanders are increasingly placing restrictions on the amount of water farmers are allowed to take from rivers due to dwindling water supplies.

We’ll fill up these basins during the year and have a buffer of water during periods of extreme drought

- Johny Verhelst

Farmers who defy bans to pump water from local waterways during periods of drought can face fines as well as jail time of up to two weeks. “Environmental concerns will only become more acute and more costly,” says Verhelst (pictured above). “And weather conditions are becoming more extreme – not just in Belgium, but in many other countries.”

Rather than fearing for the future, he insists, his invention “proves that the technology exists to prevent many of these problems”.

If everything goes according to plan, Verhelst will be distributing rainwater quality water to a dozen or so nearby companies via a five-kilometre long irrigation network by this autumn. 

Innovation grant

The sprawling plant he’s built in Langemark, West Flanders, houses several tanks: Two store manure, one purifies it, and three serve as storage for the resulting water. While this water is not drinkable, it is pure enough for irrigation purposes. The tanks hold enough to water 50 hectares of farmland during a period of two weeks

The Verhelst plant will be able to process manure year-round, their own as well as that of nearby farms. “The idea is that we’ll fill up these basins during the year and have a buffer of water during periods of extreme drought,” he explains.

Extreme droughts combined with bans on water pumping can cause entire harvests to fail, causing millions of euros in economic loss. The project was partly financed by a €1 million subsidy from the government of Flanders, the result of a call for innovative water-use projects.

Size matters: The bigger the basin, the easier it is to separate the raw material

So why is this 20-something Flemish farmer the first to come up with this idea? First of all, he explains, manure processing requires separating bacteria from the water present in the manure. While manure is 95% water, the separation process is difficult. “You need a really big installation for this,” he explains.

Farms in Flanders that process their manure on site have always built plants that were just big enough to handle the amount of manure allowed under local rules, namely 60,000 cubic metres per farm. This meant that the manure was never sufficiently processed to take the next step of transforming it into filtered water.

“We built our plant big enough to ensure that the bacteria would be easy to filter from the water,” says Verhelst. He got the idea from working on water purification technology in the Verhelst family’s other company, a washing and sterilisation service for tanker trucks.

Nutrients recuperated

Verhelst insists, however, that the novelty of his installation is not what it does – but how it does it. “We are able to transform every waste product into a reusable raw material,” he says, noting that similar manure-to-water plants exist in the Netherlands. “But they always have some kind of waste by-product that they can’t get rid of.

This by-product waste stream mostly consists of nutrients like phosphorus, nitrogen, potassium and salts. And this when nutrient reserves are being depleted at alarming rates around the world. Scientists estimate, for instance, that the world will run out of phosphorus – a nutrient that’s indispensable to animal feed and fertiliser – in 80 years.

Because Verhelst’s installation recuperates so much water from the manure, the amount of nutrient-filled leftover concentrate is much smaller, making it easier to transport the concentrate to factories that can pool and recuperate all the nutrients.

“To recuperate nutrients, you need to make them transportable, and you can do that by extracting the water from them,” he says. “So, this is a beautiful step towards a circular economy.”

Photos (c)Wouter Van Vooren