Hackney Permaculture

Making reed beds for grey water recycling

One of the projects that really stuck in my head after reading my first book on permaculture was creating reed beds for recycling grey water (any waste water from the house except sewage from the toilet).

After a good deal of time spent researching and reading around the topic the time finally came to make it a reality. Luckily there is a builders depo at the end of my street who sell gravel and my friend Morgan was on hand to help me put it all together.

For an average household you need 1m² of reed bed to recycle each persons grey water and you need four reeds per square metre. As I already had two used bath tubs to hand which came to just over 2m² and the three of us who live at 33b don’t use that much water I decided to go with that even if it was a little below the recommended area.

Ten reed plants were bought from Reeds from Seeds who can be found here – http://www.brynpolyn.co.uk/ – The total costwas £27.60 most of which was the delivery cost to London from Wales. They were very helpful people indeed explaining that late April or early May were the best time to plant.

A depth of about a metre seems to be the order of the day from a couple of diagrams I saw. The bath tubs took a maximum of about 80cm so I went with that, filling them with a layer of fine gravel on top of a layer of coarse gravel, about 50/50 of each.

It was decided after some debate to run the water into the bottom of each bath tub with water exiting out of the top. This way it has to pass up through the whole reed bed and cannot flow straight through as some designs seem to indicate. Pipes were fixed in the bottom with bricks and slate to keep them from being crushed by the weight of the gravel and to stop them from coming out. You can see that the first ‘metal tub’ reed bed is above the height of the other ‘mighty white’ tub so the water passes from the house into the bottom of the upper tub, rising through the bed to a pipe which feeds it into the bottom of the lower tub before it overflows through the bath’s original overflow into either the pond or the adjacent bed.

The metal tub was lined with a plastic sheet as it had many holes in the bottom from a previous life as a planter. Making the right sized hole for the pipe fixture was a challenge finally managed with a drill, some elbow grease and a bit of love, hence the three photos!

A lot of designs have settlement tanks and other features. I decided not to go for these yet but allowed space further back upstream to retro fit a settlement tank if needed. Whilst the reeds establish themselves I only plan to put bath and shower water into them and to use only natural grooming and cleaning products in the bathroom so there shouldn’t be anything too nasty for them to have to deal with and not too much by way of solid matter as the plug hole catches all the hairs!

Here are a few other pages of interest -

http://web.onetel.net.uk/~johndecarteret/water%20treatment.htm

http://www.green-water.org/projects.html

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