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UWCEA Zero Waste Cafeteria




Arusha, Tanzania



Project Size

1,912 sqm

Sune Mushendwa/Alexis Cronin l Baraka Sikawa


United World College East Africa



Concept Design

A zero-waste educational machine.

The basic principle of the design is to create spaces from which the students can learn about waste reduction and sustainability.

The cafeteria is designed to host 300 students and to have social areas as well as utility areas and a kitchen. All consumption and recycling processes are openly displayed so the students can learn how much energy and waste they produce and what happens to it.

Promotion of green living and education of how to be sustainable is at the forefront of the design. The building achieves this by reducing waste and energy entering the building, reusing waste and recycling the remaining waste. Solar and bio-gas are the only sources of energy and are 100% renewable.

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A number of sustainable approaches are applied to the running of the facility in order to achieve the end-goal:

  • Bio gas is made from WC waste and used for cooking and heating

  • The sludge from the biogas reactor is distributed into wetlands and surrounding organic farming patches

  • Food waste is recycled by black soldier flies to breed larvae rich in protein which in turn goes to feed the fish in the aquaponics pond

  • A by-product of the black soldier fly larvae is natural fertilizer which is used in the vegetable gardens surrounding the building

  • A 5KW wind turbine works in tandem with solar panels to produce power whereby all excess power is returned to the grid

  • A conscious effort is made to minimize the amount of packaging and other waste brought into the building. The waste that makes it into the building is sorted and recycled by the students.

  • A green roof protects and cools the building from the harsh midday sun

  • Rainwater is harvested through the central roof section. It is led down through a pipe located in the central column and stored.

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The building design intends to mimic a raised piece of earth . A green roof reduces the heat and captures rain water which trickles down into the aquaponics vegetable farm before being circulated back into the fish pond in a continuous cycle. The center of the roof harvests rain and channels in through a column at the center of the building. Sustainably grown eucalyptus poles are used to hold up the entire reinforced concrete roof creating a multi-use open space.

Biogas is produced from WC waste and the residue (sludge) is used in the outside kitchen garden as fertilizer. The biogas is used for all cooking. Solar panels on the roof surround a roof-top lounge and powers the building entirely. Food waste is fed to black soldier fly larvae  which contain up to 50% protein and are in-turn fed to chicken which end up back in the cafeteria. The larvae and chicken excrements are a high quality organic fertilizer which is again used in the kitchen garden. Any additional food waste is composted. Any one-time-use plastics are forbidden, but any eventual plastic, paper and glass waste are recycled by third party recyclers and manufacturers.

At each stage, all energy production and consumption as well as the amounts of waste produced is displayed on large monitors within the cafeteria with the goal of improving the numbers overtime.

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