Monday, 28 April 2014

Greywater oasis or 'pedoepuration'

After nearly two years of toing and froing about how to deal with the grey water leaving the house I finally decided on what is known in France as 'pedoepuration' - a system whereby greywater leaves the house, either by collection plumbing or from individual outlets and is piped to plants that are surrounded by a wood mulch which filters and cleans the water.  A sieve full of straw acts as a grease trap and care is taken to use organic biodegradable products when washing or washing up.

I referred to a book called 'Create an oasis with Greywater' by Art Ludwig which I have had for some years and never read until now.

In France there is currently no legal system for greywater outlets and dry toilets - the permitted systems are for grey and black water combined - all very expensive.  Pedoepuration can be extremely simple to install and very low cost.

 Right:  Digging a circular basin to take the wood chip and
fruit tree.  You can see the greywater channel from the house in the foreground

Left:  Testing the perk rate by digging a hole, pushing a graduated stick into it, filling it with water then noting how long it takes for the water level to go down a given amount.  A very fast or slow perk rate is not good for this system.  Fortunately here, although the ground is heavy clay, the perk rate is not too slow.

Below:  You can see the pvc collection grey water pipe coming out of the house.  We built a 'regard' using boards to shape concrete with a sloping base and with an outlet for a smaller pvc pipe to go to the fruit tree basin with a slope of 2%

below;  John checks the levels of the pvc pipes
Below:  I found a plastic container, cut off the base and drilled holes around the bottom .  The pvc pipe will go through the wall of the container and water will percolate out of the holes into the surrounding wood chip which cleans it and makes it available to the fruit tree roots.
Below: The pear tree in position - 'Pyrus communis' General LeKlerc - I was a little perturbed to have bought such a military sounding tree but ... the hole will be filled with wood chip ... and in the future when there are more people at the house I will design and install a branch to go to another wood chip basin perhaps filled with bamboo or willow to be used for basketry.

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