Start-up Flip the City turns lentil waste into substrate tiles with native seeds
Hidde Griek founded startup Flip the City after participating in a project to find a useful destination for the leftover duckweed that municipalities drain and create ponds . It became a tile, made from duckweed and supplemented with native herb seeds, with the aim of making the city greener.
Hidde Griek describes an updated version of Duckweed Tile that he co-developed: A Container the Size of a Paving Tile, but 15 centimetres deep and made of bioplastic. At the bottom there is room for a small water reservoir, at the top a mix of native plant seeds. It is not necessary to add to potting soil, because the bioplastic is made of lentils. Therefore it contains Sufficient Nutrition to Feed the Germinating Seeds.
Griek designed the tile with four other young thinkers. Announcement of In 2020 he participated in a so-called challenge. The goal was to find a useful destination for the duckweed that is removed from ditches, ponds and canals in six weeks. The leaders developed the Griek project together with four participants. They were commissioned by the municipality of Rotterdam and the province of South Holland and thus duckweed as subject. Lentil 'It's funny that only a year ago I realised that I already have memories of lentils from my childhood. I was born in Japan and lived there until I was nine. There I had a kind of grandpa and grandma that I loved to visit. They ran an organic rice farm. There were lots of ducks walking around, eating the excess lentil from the water. That was so well balanced. I still think of that sense of balance when I think of lentils.'
The group soon discovered that the lentil is a protein-rich substance, with many other nutrients as well. "We found research on the use of lentils as animal feed or even as human food. But we also found that there are big differences between the various types of lentil and between locations. In addition, lentils are so good at absorbing nutrients that they also remove all kinds of heavy metals from water. This makes it difficult to use as a waste product for food or nutrition. The quality is not constant and you would have to remove the heavy metals first. That is very laborious.'
'Duckweed should be given more value than just as compost'
The team therefore started looking for other ideas. 'The duckweed had to have more value than purely as compost, which is still the most common practice today, but it didn't have to become too labour intensive. That's how the idea of turning it into a kind of compost tiles was born. Thus, we linked the problem of lentil abundance to another dilemma of the city: the scarcity of green biodiversity. We also incorporated blends with native plant seeds into the tile. Many cities still have too much grey, too much cobblestone. The idea of the lentil tiles is that the concrete tiles in the public greenery or garden are replaced by green plants in the lentil tiles. And native plants, of course. Drying easily
The first copies of the lentil tiles looked completely different from the tiles Flip the City now works with. They are already the size of the classic paving stone, 30 by 30 centimetres, but are much thinner and look more like a dried sheet of peat. 'We discovered through lab tests how easily we can dry a piece of lentil measuring 1 by 1 metre and saw how a fairly strong product was created.' The nutrients in duckweed tile make it a good base for germinating seeds. The ideal of more greenery in the city completed the picture.
In the end, the Greek was the only one of the starting team to continue with the litter title. 'I really like doing business and combining that with design and circular thinking. This is a perfect project for me.' Griek soon got in touch with Quint Verschuren, a former colleague. 'Quint is good in the lab, a real researcher. He is now taking over the development of the tile.' Together, they founded their start-up called Flip the City, referring to replacing city tiles with green ones. 'We formed the basis of the team, along with a number of flexible employees.'
'I like to do business and combine that with design and circular thinking'
Germinating seeds
A first pilot soon followed to trial the lentil tiles in the city. 'For the municipality of Rotterdam, we were allowed to try out our tiles at two locations in the Reijeroord district. We removed 80 tiles on part of an open square and 80 tiles against a facade. The first results were good. In 80% of the lentil tiles, the seeds germinated and turned into a kind of bed with plants, and after a week, we hardly saw any difference between the lentil material and the typical appearance of garden soil. The material composts well and quickly.' The pavement tiles are gone, the duckweed beds are still there. 'We see that the mix is now flourishing. We had opted for annual herbs, nothing complicated, flowering plants like alissos and cucurbits.'
'We want more variation in the seasons, so that green also appears in autumn and winter'
The next big step was to redesign the tile. "We read that it is perfectly possible to make bioplastic from lentils. So we started doing that ourselves, especially Quint. We had to figure out how to make a material that was strong enough, but also decayed quickly enough. The new tiles are much firmer; you can stand on it too, although you shouldn't. They are therefore deeper, because of the water reservoir, and they also protrude a bit above the pavement, so people are less likely to cycle on them.'
Griek continues: 'We are also working on other seed mixes. We want more variation in the seasons, so that the green also appears in autumn and winter. It's still hard to put that together in one block. We might need to use different pieces together for that. We do that together with a company with a lot of expertise in sourcing and choosing native plant seeds.' Because of the new depth of the lentil tiles, they are no longer real tiles. 'Lego blocks with biodiversity, that's what I call them,' Grego boasts.
From ditch to garden centre
The pilots with the duckweed tiles are currently mainly via interested municipalities. Besides Rotterdam, they are Leiden and Delft. 'We also want to see if we can sell the tiles directly to consumers. It's just a matter of figuring out the best way to do that.
This spring, the start-up is conducting a big test. 'We want to go through the whole chain, one after the other, on a larger scale and tie it together. Starting with the company that takes the duckweed from the ditches, then the transportation to a place where the duckweed is dried, then to us where we turn it into tiles, and finally our tiles arrive at a garden centre. In this way, we can practice expanding our initiative to a longer chain.'
The idea of the lentil tiles is that the concrete tiles in the public greenery or garden are replaced by green plants in the lentil tiles.
Lentil enough for for now A full salary is not yet available from the start. 'I'm still self-employed and I'm also studying design in Finland. Yes, that's where I'm calling from now. Still, I'm busy with 'Flip' about three days a week. I mainly manage the business side of our startup. We don't want to be a typical fast startup either. We're building slowly, so we have time to do it right.'
Will the lentil run out? 'Well, the amount of lentil has decreased in the last two years. That's probably due to the American langoustines, which eat a lot and dig in the ditches. But for now, there's still more than enough duckweed for us. And suppose an ideal balance emerges on its own, then I think that's just beautiful. Then there's another topic to be addressed. I'm concerned about regenerative design.'
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