Press release | 18 August 2020 | sn

Fresh veggies from “Shower-Tower 61”

Shower water as a resource in food production: In the vertical hydroponic farm at Berlin’s Gleisdreieck Park, different varieties of perfectly hygienic lettuce, edible flowers, and herbs are to be grown using the water

For the first time in Berlin, a vertical hydroponic farm combined with a local water recycling unit was constructed in an urban open space. TU Berlin scientists and students aim to research whether foods such as lettuce, cabbage, edible flowers, and herbs can be produced with treated shower water and consumed without any health implications. The vertical hydroponic farm “Shower-Tower 61” is located within the beach volleyball facility “Beach 61” at Gleisdreieck Park near Potsdamer Platz.

In hydroponic farming, plants are only grown in an aqueous nutrient solution without soil. The innovative feature of this vertical hydroponic farm is that shower water, in other words waste water, is used to grow the food. The vertical farm consists of eight two-meter-high white square columns, which are mounted directly on the back wall of the showers at the volleyball court. Sixteen plant tubes are planted in each column. Mesh pots with plants, stabilized with expanded clay and fabric, are then inserted into the tubes. The treated and nutrient-enriched shower water drips into the tubes from above and waters the roots protruding from them. This provides the plants with water and nutrients. The vertical hydroponic farm is suitable for growing lettuce varieties, herbs such as basil, cabbages such as bok choy and red kale, turnips such as chard as well as edible flowers.

Researching the use of real-world laboratories

The “Real-World Lab Mobile Blue Green Infrastructure” was built together with students from the TU project laboratory “Roof Water-Farm” led by Dr. Grit Bürgow, student coordinator Andreas Horn and architecture student Gabriel Sigler. It is a prototype.

The research questions they aim to investigate using this real-world laboratory are part of the research project “GartenLeistung. Urbane Gärten und Parks: Multidimensionale Leistungen für ein sozial, ökologisch und ökonomisch nachhaltiges Flächen- und Stoffstrommanagement“ (GardenService. Urban Gardens and Parks: Multidimensional Services for Socially, Ecologically, and Economically Sustainable Management of Urban Areas and Flows of Materials).

The aim of the GartenLeistung project is to explore in four real-world labs how the role of gardens and parks for the urban climate, biodiversity, and people’s quality of life can be integrated into political decisions to ensure more sustainable management of urban areas. The scientists are also researching how social exchange, integration, participation, and transformative learning can be promoted using such real-world laboratories. GartenLeistung is headed by the Institute for Ecological Economy Research (IÖW) Berlin.

Dr. Grit Bürgow, Chair of Urban Design and Urban Development, is the coordinator of the “Real-World Lab Mobile Blue Green Infrastructure”.

The advantages of a vertical farm

“We want to answer four important questions with our farm. First of all, is it even possible to treat shower water with existing technologies so that it can be used for producing food that is completely safe for consumption? The second question that needs answering is whether such a vertical hydroponic farm is suitable for local commercial and non-commercial food production in an urban environment like Berlin. Thirdly: Is it possible to involve the population in this kind of project on an ongoing basis with the aim of ensuring that such blue-green infrastructures are operated and used by local residents themselves in the future? Fourthly: What effects does such a hydroponic farm that is combined with reed raised beds (which allow for evaporation) have on the urban microclimate?,” says Bürgow. Being able to answer these questions would pave the way to finding solutions for climate-friendly urban development.

In order to prove that gray water treatment, in this case shower water, can be combined with food production and that food safe for consumption can be grown with treated shower water, the water used must meet the DIN standard for irrigation water.

The major advantage of this type of vertical farm is that it does not take up much space in urban areas, which are both scarce and expensive. It can also be installed on facades and the walls of houses. Just like the University’s “Shower-Towers 61” on the back wall of the showers. “This is really efficient,” says Bürgow.

Can the local population be successfully integrated into the project?

Given that their farm is actually a laboratory and that the research is carried out directly in an urban area, Grit Bürgow, Andreas Horn, and Gabriel Sigler are also in close contact with the operators of the “Beach 61” bar. The scientists point out, “This interaction is important in order to find out if people are willing to accept these innovative ideas. For example, is the operator of the beach club interested in using the lettuce and herbs in their bar? Is it realistic to imagine that they might operate a farm like this with us or even on their own after the end of the actual laboratory research?” The added value is clear: short transport routes and dewy fresh herbs for pizzas and cocktails.

The GartenLeistung project is funded by the Federal Ministry of Education and Research as part of the initiative “Resource-efficient urban districts (RES:Z)".

Note: Many thanks to Petra Wiesmayer whose article provided the foundation for this English translation.