Field Trip — Roof Water Farm Test Site, Kreuzberg

More info coming soon.



An apartment block with combined water recycling plant and aquaponic and hydroponic farm.


The Building with Second Piping
Block 6 in Berlin-Kreuzberg was originally developed as part of an International Building Exhibition in 1987 though it’s now used a normal residential apartments. The notable feature of the apartments is that it has second piping – this means the grey and black water is separated. Grey water being the waste water from bathtubs, showers, washing machines etc. Black water being the toilet water.

Water Management
Rainwater – collected in the reeds wetland surrounding the recycling station.

Black Water
Black water is treated to produce a liquid fertiliser, named ‘gold water’ after it’s post-treatment colour. The liquid fertiliser is used in the hydroponic farm.

Grey Water
Grey water is treated and transformed into bathing quality water and used to flush toilets and to water the gardens. And is ported to an adjoining aquaponic and hydroponic farm.

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Grey water at the start of the treatment process


As the treatment progresses the water has less visible particles.


The aquarium serves as a ‘canary in the coal mine.’

Hydroponic & Aquaponic Farming
The treated water and fertiliser is then ported to an adjoining hydroponics and aquaponics farm. The soilless farming system weighs significantly less than a traditional soil farm and is thus easier to host on a roof top.

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Heat Transfer
The heat from the grey water is also transferred to incoming water through a heat exchange.

Problems addressed

  • Water cost and supply
  • Stormwater drainage issues
  • Peak phosphate
  • Food transport

Photos by Susanne Feldt, phone photos by Mei.

Further Reading

7 years ago

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