Plumbing the grey water into the dunny would be easy enough I think – although since our house is “high set” it would be a gravity-defying feat for us. But, I think it would be doable.

Our water goes through sand, gravel and then into more gravel with compost and plants growing and it can still smell. I took a pH test the other day and the soil within the “wetland” was very alkaline (pH of 11) so I suspect that might have had something to do with it. Interestingly, the smell never comes from the surge tank closest to the house, so I would be happy to run water directly from their into a downstairs toilet (if we had one) and don’t think it would smell.

The sand helps to get rid of the “pieces” – hair, toenails, bits of food, etc, and it also seems to do a great job on grease and fats and things like that.

Hope it helps – let me know how it goes for you.

Bryan

I guess the best indicator of the sand is the colour of it! It has turned from coarse sand to black sludge. I guess that means that it worked quite well. Perhaps the only problem was that my surge tank was too small, meaning that there were times when there was water entering the system faster than it left. I have since moved to a simple system that is a larger single tank. This has gravel of different grades at the bottom, rising to sand at the top. The grey water enters directly into it at the top, and out from the bottom.

Before I put the sand in, the water coming out of the “wetland” was quite acrid and stinky. With the sand as the first filter, this has stopped and, interestingly, the growth in the wetland has accelerated. I am not sure what it is that the sand removes from the water, but it seems to be better when it does.

Glad to share ideas – how about a guest post on this blog to show what you are up to – no pressure, but the offer is there if you want it.

Bryan

Thanks for dropping by. I was just outside looking at the thing – it has been doing its thing for a couple of years now.

I am not sure where you are, but grey water is a bit problematic for many Australian plants – they have trouble with too much nutrient. Having said that, our grey water goes into a swale, at the other end of which is a large eucalyptus tree that is doing very well.. I suspect that most of the nutrients are taken by other things before it reaches that tree.

Vegetables is also seen by some as an issue, given the potential for spread of pathogens/disease etc. I’ll let you make up your own mind on that one.

In terms of how much area is needed, i think it depends on how much area you have. We have a fairly large yard, so space was not a problem – our area was determined by the materials we had to work with. I have seen it working in a bathtub, which makes ours look really large. But, I have also seen a whole swamp, which makes ours look tiny. My thinking is that if it is small, then run less water to it, and it is easier to increase its size than to decrease it.

The other thing that will likely affect its effectiveness is if you use a surge-tank, prefilter before the water goes to the wetland. Without that, the wetland would need to be much larger to handle the volume of gunk that comes out of your house. I replaced the sand/gravel in our prefilter and it was black after only about 6 months.

Hope this helps…do let me know how it goes for you.

Bryan

Glad you enjoyed the post. The whole system has been working well for 18 months or so. We had to replace the black bins, since the holes that I cut for the pipes were not perfectly circular – when combined with being plastic and filled with gravel, the flex in the walls led to some leaks.

The second black bin contains coarse gravel at the base, finer gravel in the middle, and sand at the top. About half of it is sand, with quarter each for the others. These materials serve as a filter for the larger particles that are in the water, eg, hair, food bits, etc.

The large water tank base is a permanently wet place, with the gravel size such that bacteria and other miniature things can grow and help to clean the water as it sits in there. The only time water leaves the system is when additional water enters it. This means that there is always a constant amount of water. This will limit what you can grow in there. I have grown a range of wetland type plants, such as some grasses and rushes, which I have then slashed several times to use as mulch in the adjacent orchard area.

So, our waste water gets cleaned by plants that provide mulch and food to our fruit trees; and the water is used to water the fruit trees.

It seems to be working okay so far. Let us know how you get along, and thanks for dropping by.

Bryan

I intend to do something similar to what Adrian is trying – a fish pond, probably with some ducks; and then overflow to water the garden. I live in India where it can be a very dry 9 month period after the monsoons – so pretty excited about trying this. Will get back later with progress.