These are our current plans and thinking for greywater recycling. We have bought some items that can be transferred from our current house.
In our new home we plan to collect greywater from:
- Sinks (but not the kitchen sink)
- Washing machine
This will be achieved using dedicated pipework, designed into our new house from the outset. All of these sources will lead to a single outlet pipe to the outside of the house.
The main outlet from the house will pass through a filter to remove any debris, before going into a holding tank. The holding tank capacity will be determined by how much greywater our household generates in a typical day, because you shouldn't really store greywater for much longer than this. We have already purchased a 350 litre tank, which should be adequate. You can also buy disguised or decorative water butts in these kind of sizes. The holding tank is used to simplify distribution and usage. The tank will have a tap at its lowest point (to ensure it completely empties) and this tap will be used to fill buckets, watering cans, etc. This does mean that the tank needs to be raised slightly, to at least allow a watering can to be placed under the tap. With our installation that is not strictly necessary though, as we are using a 12V pump to distribute the collected water via a hose pipe. Underneath the tap will be a drain leading into more pipework, taking any excess or unwanted greywater to a reed bed for treatment. The tank overflow will also drain into this pipework. Leaving the tap open will ensure all greywater passes through to the reed bed.
We have purchase an Ecosure 350 litre sandstone water tank for use in our current and future home. It is the same colour as our current house brickwork and is designed to blend into the garden a bit more easily than a typical black water tank. This tank is also nicely sized to sit on a 90cm x 45cm paving slab, raised up on four courses of bricks.
To support flexible water usage, we have fitted a brass tap to the tank, with a snap on hose connector. This means we can use it to fill watering cans if required or it can be connected in to our irrigation system.
More typical usage involves connecting the output to a 12V pump to boost the pressure and distribute the water around the garden via a hose pipe.
To stop the pump clogging up with debris, the pump is fed through a filter. We have used a ShurFlo inline filter designed for use in boats and caravans as this doesn't restrict the flow.
The idea of linking the rainwater harvesting system to the greywater system is also being considered. The thinking is that any excess rainwater (once the storage tank is full) could feed into the greywater storage tank, to flush it through or dilute the greywater before use. The practicality of this depends on the various heights of the tanks and pipework relative to each other though.
Our plans are only to use the greywater for irrigating the garden and plants. It will not be used on plants grown to be eaten though or areas of the garden where food might be grown to eat. The rest will be treated and used to fill a pond.
In our current home the water is put on flower beds and lawns. East Anglia gets very little rain and this water is the only thing keeping our lawn alive through the summer months. 2010 was a dry summer and so far 2011 has been especially so.
The plan is to have a reed bed in our garden for excess greywater treatment, leading into large ornamental pond.
What Have We Learnt So Far?
In doing some experiments in our current home, we have learnt quite a few things.
- Firstly, the whole process needs to be kept simple and reliable, to minimise the amount of time spent collecting and distributing grey water. If it entails a whole lot of effort and time, then greywater recycling is unlikely to succeed long-term.
A key element of making the whole process efficient is to have a powerful water pump that distributes stored water quickly.