The Birla Institute of Technology and Science, our partner in the G2RT field tests, asked us if we could develop a simple vacuum system for India. BITS professor Srikanth Mutnuri is conducting research there on plant-based wastewater treatment, as well as on biogas production. Our discussions subsequently led to the idea of combining both technologies – as reflected in the project name.
The Spanish manufacturer Roca supported us with prototypes by adapting the geometry of our Save! toilet model to work with our vacuum system. Urine and almost all flush water can be drained out of the toilet and the residue is used to produce biogas. The Biowets project aims to protect groundwater and recycle wastewater into process water.
A public toilet on the beach in Goa, with the wastewater treated in a plant-based wastewater treatment unit. The research project at BITS Pilani University was an important preliminary step for our joint project. By using a biogas tank and draining off urine and flush water, the area required for plant-based wastewater treatment could be reduced considerably. Once again, separating the treatment systems for solid and liquid waste proved to be highly advantageous.
Drawing by Professor Srikanth Mutnuri with a biogas tank in the shape of a cow’s stomach. His original idea was to create a cow-shaped design for the biogas production system.
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The gas produced is stored in a gas tank and used for cooking, for example.
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The functional diagram shows how urine and flush water are separated in the toilet and directed directly into the plant-based wastewater treatment unit. Solids with little residual water are transported by vacuum into a biogas tank. Methane is produced and stored in the tank. Excess liquid from the biogas tank is also purified with the plant-based wastewater treatment system.
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The vacuum tower we developed. The green hose leads to the gas tank, the yellow lid at the bottom is used to fill leftover food directly into the gas tank.
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The teams from EOOS and BITS Pilani installing the test toilets. The vacuum urine separation toilet from Roca with an electric flush release for large and small flush volumes. The flushing pressure is generated by the type of water pump generally used for windshield washer systems on trucks – a cost-effective solution.
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