www.permaculturenews.org/2014/04/08...na-circles/
Banana circles can be used in tropical and sub-tropical areas to utilise waste water, run-off or overflow from rainwater tanks, and even urine waste from dry composting toilets.
It is possible to use other plants in a similar system, but bananas are an excellent choice as they are very heavy feeders and also need a lot of water to be productive. The fruit from banana palms is highly nutritious and so in developing countries banana circles are a great way to turn waste into a valuable food source for the whole family.
At Kesho Leo in Tanzania, banana circles are used as a part of our compost toilet and grey water systems.