Europe's biggest!

There aren't many things in our small town of Härnösand (population 25,269) that can boast they are the largest in Europe but there is definitely one, and here it is.
What you see in the picture is a greenhouse, built to grow tomatoes all the year around. It’s 4000 square meters, big but not especially impressive in terms of greenhouse agriculture.  What is special here is that the tomatoes will be grown without the use of pesticides or fertilisers, using very little water and without waste. Alongside the 200 tonnes of tomatoes the greenhouse will also produce 20 tonnes of rainbow trout.
It’s an environmentally friendly, closed loop system. The fish get fed, they poo, the nutrient rich water from their tanks is pumped away and dripped into the gravel beds in which the tomatoes are planted. The tomatoes grow using the nutrients from the fish, naturally occurring bacteria in the gravel beds clean the water, which drips into pipes under the gravel, and the now clean water is pumped back to the fish tanks, and oxygenated, to start the cycle again.
All the inputs come from organic or renewable resources.
The outputs are tomatoes, fish, a small amount of solid fish poo, and at the end of the year a large pile of tomato plants.  The fish and tomatoes are sold locally. The fish poo is organic fertiliser. The old tomato vines are recycled via the town’s compost or biogas generator.
For every kilo of fish food going in, the system delivers 1 kilo of fish and 10 kilos of tomatoes.
I’m a natural sceptic but the originator of the system, Pekka Nygård, has been experimenting for twenty years on a smallish scale and it seems to have worked amazingly well. His fish have never got sick and his plants have thrived, using the same gravel beds for 15 years.  The greenhouse technology comes from Närpes in Finland, which has a similar sub-artic climate, and where they have been producing huge amounts of greenhouse grown food on a much larger scale but using less environmentally friendly methods.
So that’s it! I wish them every success as they scale up the technique in Härnösand, in Europe’s largest environmentally friendly closed loop agricultural system. They have already got the land in southern Sweden for a similar project but ten times larger than here so it seems Härnösand won’t be Europe’s largest for very long.
(The extra shows the greenhouse from the outside, but could be the most boring photo I've ever put onto Blip!)