This idea came from the work that we do with sewage. Our systems produce a clean water effluent that is clean enough to discharge to ditches ponds etc. we wanted to develop a tertiary treatment system that would allow us to re-use the water for irrigation purposes. Hence the idea formed to create a hydroponic bog garden.
It essentially uses the same techniques employed in aquaculture. Use bacteria that are attached to biomedia to clean the highly oxygenated water passing through the media. We use alfagrog media for this. It has a high surface area and good void capacity. The added bonus to this system is that by placing a gravel bed over the top of the media we have been able to produce an ideal environment for growing those difficult to propagate plants. The moisture loving ones that fail at the first sign of drought.
You can find out more about us and our other projects on our site: Biotank