The FSSU (floating sustainable sanitation unit) is a full off-grid solution for domestic sanitation problems. The system consist of a floating body, a special develop construct wetland and technical components like pumps, pump controls and pipes. The main characteristics of the FSSU is a vertical flow construct wetland (VFCW) and a floating body.
The general principle of the treatment by means of a VFCW is percolation of the wastewater through a layered filter package that acts as a biochemical reactor. On its way down, several complex biological, chemical and physical processes take place. The main ingredient of the filter is sand or lava; and on top of the filter, some varieties of reeds are planted, the root zone of these plants are instrumental in the purification process. In the root zone, biochemical transformations, supported by oxygen from the reed plants, break down harmful substances in the wastewater, creating a purification level of approximately 99%.
Firstly al the wastewater is collected from the house, and stored in a sedimentation tank. The water from this sedimentation tank (often a septic tank) is being pumped into a distribution network in the top layer of the VFCW. From here the water percolates through the filter package, and the root zone of the reed plants, into the drains on the bottom of the package. A VFCW is a well-known purification solution for decentralized regions where central system is technically or economically not attractive. VFCW are commonly installed underneath at ground level for environmental protection and low visual impact.
The average dry weight of a conventional VFCW is approx. 1900 kg/m3, which makes it technically challenging for floating. For this reason we have adapted the filter substrate in such way that we reduced the weight with more then 50% depending on the local available materials.