BUILD YOUR OWN GREY WATER IRRIGATION SYSTEM – Part 3

July 19th, 2009 by Tim Leave a reply »

Part 3 Installation

Although my floor level being about a meter above ground level, meant that the tank could be above ground – I decided to bury the tank so it was out of the way and less of an eye sore.

Tank Installtion - backfilling

Tank Installtion - backfilling

Most plastic tanks are not designed to be buried and will collapse, but if you fill them with water and then backfill the surrounds with a sand/cement mix this hardens into a nice compressive ring that doesn’t collapse (I use a similar method on my rain tanks which are much bigger and deeper and it is working a treat). A word of warning though if you have a high water table and then tanks are empty they do tend to want to float.

The picture shows the backfilling process with the 40mm(3/4”) in and overflow not yet connected. The overflow is connected to the sewer through a standard u trap to keep smelly gases in check.

The pump was then installed with a non-return valve right at the bottom which stops the pump becoming de-primed.

Sump View showing float switch

Sump View showing float switch

Also in the photo is the float switch which allows the tank to fill about halfway before it turns the pump on. On reaching empty it then turns the pump off again. It is a simple mechanical switch and is simply wired to the pump circuit in series.

Finished product :

Total cost of project : R 2000 ~ $200 give or take

Finished product

Finished product

A note on the sprinkler – I decided to keep it simple and I have an outlet in one of the beds with a long length of hose so it can be moved around. The sprinkler is a simple one with a large nozzle which won’t block easily.


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2 comments

  1. Kevin says:

    Hi Tim

    Great projects!

    I’m busy upgrading all my gray water & rain storage fascilities with some new ideas.

    Some options for you to consider:
    Level control switch:
    I’m using ‘Washing Machine Pressure switches’ – you just need to run a piece of clear plastic tubing out to your tanks instead of cabling – the switch can be safelly mounted in a weather proof area.
    Pumps:
    I find small wellpoint pumps to be the best – also available quite cheaply, but can happilly ‘suck’ from about 30 meters away from the tanks, and give great pressure for the sprinklers – Can also attach a constant pressure system onto them.
    Reed bed filters: (Google them – you’ll find plenty of info.)
    If you have the space, you can build a reed bed, that just gets filled up with gravel, plant various reeds & water plants in it – take the water through the reed bed then into your sump.
    The reeds stop the recycled water from smelling & creates an attractive evergreen garden!

  2. admin says:

    Hi Kevin – thanks for the tips – now you come up with your bright ideas I’ve had one of those pressure switches in a box for years!

    Regards reed beds I don’t have space for the grey water but am busy designing one for my fish bond to keep the water clear (remove nitrates). My ultimate plan is to expand this idea to create a ‘natural swimming’ pool. So I hear where you coming from.

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