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11 - Recycling human wastes at a student dormitory in Aas, Norway |
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| Project name |
A complete recycling (ecosan) system at student dormitories in Norway Figure: The complete recycling system at the student dormitories based on separate treatment loops for black water and grey water |
| Keywords |
Waste water recycling system based on ecological engineering principles built in As for 48 students. |
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| Start of the project |
1997 |
| End of the project |
Still in operation |
| Contact person |
Prof. Dr. P.D. Jenssen
The Norwegian University of Life Sciences
Aas (30 km south of Oslo),
Department of Mathematical Sciences and Technology,
PO Box 5003,
1432 Aas Norway
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| Short project description/project function |
The Agricultural University of Norway is pioneering environmentally safe solutions to organic waste and wastewater treatment. A recycling system based on ecological engineering principles was built serving apartments for 48 students.
The concept is based on:
- Separate treatment of toilet water (black water) and water from the kitchen and shower (grey water).
- Vacuum toilet use, reducing the water amount to 1 l instead of 6-20 l per flush.
- Liquid composting of toilet waste and organic household waste; this can be substituted for or combined with biogas production.
- Filtration of grey water for production of a water quality suitable for simply discharge to a nearby stream.
- A patented machine for ‘shooting’ the liquid bio-fertilizer into the ground.
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| Summary of experiences |
In order to kill pathogenic micro organisms and to remove odours the black water must be treated in a liquid composting reactor. In this reactor the black water is mixed with milled organic household waste. The composting material meets the standards of the European Union. The slurry from the liquid composting can be applied directly as liquid fertilizer into the ground.
The grey water is treated in a three compartment septic tank, followed by an aerobic bio filter and a constructed wetland. |
| Project benefits |
The system reduces water consumption by 30 % (even 50 % is possible), it nearly eliminates pollution, and it produces a valuable plant fertilizer and soil amendment product from the waste material. |
| Project level |
Mature technology |
| Financial scale |
Beside the investment in the construction the major maintenance costs are collection of the toilet waste once a month. The grey water treatment system has no maintenance needs in the first 5 years.
Because of the dual piping system the in-house plumbing is more expensive.
The system is economically competitive, especially in areas where no sewage network exists of where there is high costs connected to building or upgrading an existing sewer. |
| Environmental conditions |
Climate: humid temperate with marine influence |
| Altitude |
10 m above sea level |
| Description of special local conditions |
- |
| Why this is ecological engineering |
The described integrated system recycles most of the nitrogen and phosphorus in the waste water, reduces the need for pipelines, replaces expensive chemical fertilizer, reduce transport costs as the nutrient can be used locally, makes energy production from waste possible, saves 30-50 % of the domestic water consumption and grey water treatment facilities can easily be adapted to the terrain. |
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Last Updated ( Friday, 26 October 2007 )
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