Reeds beds are a useful way to filter and reuse waste grey water. Those who live in a house (and not an apartment) can easily make a reed bed in their garden. We made a reed bed next to our Outhouse to clean and recycle the grey water emerging from the washroom and pantry.
To make a reed bed, dig a trench about 4-5 times the volume of the daily quantity of grey water you are generating and would like to filter through this channel. Create a gentle slope towards the outlet side of the reed bed, so that the water moved slowly from the inlet side to the outlet. Put a soft layer of straw/ carbdboard/ old carpet at the bottom so that any sharp stones are covered up.
Cover the entire trench with a thick layer of plastic. Make sure the plastic does not tear when you are doing this.
Introduce a layer of big stones at the bottom of this trench.
Make a tight hole in the plastic and introduce the inlet pipe (grey water outlet) through this hole at the bottom of the trench. Drill a few extra holes into the pipe to get a gentle flow of grey water.
Fill up the trench with stones, and add fine gravel and earth towards the end.
Plant locally found reeds and grasses in this trench to create a reed bed. As the water enters the Reed Bed and flows gently from one end to the other over days, the roots of the reeds work on the organic matter and detergent molecules and break them down into safer non smelly molecules. A clean stream of water emerges at the other end. This water can be used for watering plants or simply as a small pond for wild life and plants.
Over the months, the reeds grow to look like this - a pretty feature in the garden!
Here is a video that describes this process in equal detail, and you may find it useful!