I think that this is one of the most exciting things that I have embarked upon…Progress on the grey water system has been progressing well, and it is now connected and working well enough to have confidence that we can plan the orchard based on the water that it provides.
For the sake of completeness, and in response to some requests for a bit of detail, the following outlines what we have done to date.
Once our old water tanks were removed, I emptied the sand from the base of one and rolled it to where we wanted the wetland to be. [Actually, it has been rolled around to several places because it always seemed to be getting in the way – it also found a use as a pretty good chicken house for our young chickens). The thing is just a circle of corrugated iron, with not base. I roughly levelled the ground under it to get the top level, and removed any sharp objects. Then I bought a $3 tarpaulin and lined it. As an extra precaution against tearing, I put the base of the inlet pipe in a small container. The inlet pipe has holes drilled in it so water may seep into the gravel at any level, and more quickly than if we were relying on entry from the base alone.
Once lined, we filled it with gravel. I’m not usually a fan of child labour, but when it’s my own kids and they enjoy it, it seems okay. The gravel is rough and about 14mm.
The gravel was added to just cover the outlet pipe, which extended about 450mm from the side into the wetland. It also had holes drilled into it.
At the other end, two garbage bins were arranged to allow the first stage of cleaning. The stand is something that I found in a dumpster at a university. The top one is the surge tank, and simply serves to allow water to drain quickly from the bath, sink, etc. It also allows a higher pressure for the water to flow down from its base and through the base of the lower bin. The surge tank is covered with some shade cloth that I had laying around; this catches the bigger bits in the water, and prevents mosquitoes from gathering.
This water then moves up through two layers of stone and a layer of coarse sand, and then out the pipe at the top which takes it to the wetland. Again, kids were invaluable in filling the bin with sand.
Before doing anything extra, I ran a load of washing to see whether the plumbing was right. To check water flow into the wetland, I removed some of the gravel from around the inlet to check water was coming out the holes…
and checked also that it was going through the holes of the outlet pipe, and thence out of the wetland. It works!
To prevent mosquitoes from getting too excited in the wetland, we covered the gravel with about 100mm of mulch.
The next steps?
- Source some wetland plants and plant these directly into the gravel to further assist in the cleaning of the water.
- Connect the bathroom, kitchen and laundry sinks to the system.
- Connect a hose to the wetland outflow to allow the water to be directed to trees in the orchard (oh, and plant trees in orchard).
As I said, Very exciting stuff.
21 responses so far ↓
1 Judith // Sep 14, 2007 at 10:53 am
Wonderful, Bryan! Very inspiring; I love it. Looking forward to further updates.
2 craftydabbler // Sep 14, 2007 at 12:39 pm
Wow! That is really cool. I can’t quite figure out though, if the water drains from the house into the top bin and then down to the lower bin and then out, or if it is the other way around.
3 admin // Sep 14, 2007 at 12:52 pm
Hi crafty’
The order is: House to top bin to bottom bin to wetland to garden. The weird bit is that water enters the bottom of the bottom bin, then exits from the top of the same bin before heading out to the garden.
Bryan
4 Jacqui // Apr 6, 2008 at 10:51 am
Hi, I’m very interested in learning about creating my own wet land. How do you get the water out of your house into the bins? Can the process work effectively without the bins; with the water going straight into the wetland?
Keep up the good work.
5 admin // Apr 6, 2008 at 7:54 pm
Hi Jacqui, and thanks for your interest. Our design has the bins situated almost immediately beneath the bathroom, which just happens to be near the laundry. To get the water into the bins, I simply connected a bit of scrap poly pipe with some bits of scrap wire from the outlet pipes (below the s-bend) to rest on top of the top bin.
The problem with this is that when the bath was emptied at the same time as the washing was done, then we got too much water and it overflowed. That’s why we replaced the top bin with a much larger version, about which there is a more recent post somewhere in the blog.
I have previously tried to direct the grey water directly to the wetland, but the problem this created was that the water entering the wetland was at such a low pressure that it was really slow at draining, such that in even a brief shower, you’d end up with water pooling around your ankles. Of course, you could get around this by having the water enter the top of the wetland, but then you could not be sure that it was filtered before leaving from the outlet that has to be at the top.
Another, perhaps simpler design, would simply be to run the grey water straight into a large diameter agricultural pipe/gravel drain that is covered by a thick layer of mulch, and is planted out on either side. I would presume that if the pipe was long enough, then it would hold sufficient water to avoid the pooling effect.
Hope it helps. Let us know how it goes – feel free to make some “guest posts” about what you are up to.
Bryan
6 Paul // Jun 30, 2008 at 9:00 am
Hi,
Very nspired to adapt our grey water system here in Australia to create our own wetland area.
A question I have is aftere all the filtration is the water able to be used for watering livestock such as horses..? We are currently in a 10 year drought here.
7 admin // Jun 30, 2008 at 12:02 pm
Paul
Thanks for dropping by. I have not tested the output water quality, and this is not something I have considered since our output is underground. I reckon it would have a lot to do with what goes into the water in its first use….
Sorry I cannot provide greater advice.
8 Adam // Aug 30, 2008 at 6:30 am
Paul,
Thanks for taking it to the next level. I love it when people take their knowledge and instead of just talking about soothing, actually putting the sweat equity into getting something done.
Alter the Eco and keep up the good fight,
Adam
9 Adrian // Sep 12, 2008 at 6:41 pm
awesome, I love it. My whole plan is todo the same but with a large fish pond receiving the flow. And the fish pond has a lip to allow excess water to run to the plants. Got to use non-abbrasives in the kitchen and bathroom though for the sake of the fishies!
10 sc // Sep 22, 2008 at 10:53 am
I notice that the air conditioners at school (and home) put out a lot of water…I guess that’s gray water? So…how could we collect it and put it to use in a reasonable way?
11 admin // Sep 29, 2008 at 4:59 pm
G’day SC,
The first thing that comes to mind is to somehow divert it to the roof, and allow it to trickle across the roof and evaporate – thus reducing your roof temperature and, perhaps ironically, the need for air-conditioning. Otherwise, I would divert it straight to a perforated pipe buried in about a foot of litter and just plant either side. But what I recommend may be neither legal nor sensible, so check out your health authorities’ requirements first.
Thanks for stopping by.
Bryan
12 Shreesh // Dec 30, 2008 at 4:09 am
Great work, 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.
13 Shreesh // Dec 30, 2008 at 4:38 am
Sorry to spam, but found another great site : http://frogs.org.au/frogwatch/greywater.php
14 Ishay Lev // May 19, 2009 at 4:17 am
Thanks very much for this wonderful and cheerful description –
Wanted to know : what and how much staf do you put into the 2nd black bin ? Can I grow stuf freely in the large water tank bases ?
Ishay
15 admin // May 19, 2009 at 7:09 pm
Ishay
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
16 Gerry // Oct 29, 2009 at 3:44 pm
Bryan
How muck area is required?
I would like to run the water trough the wetland to water natives and vegetables but space may be a problem.
Thanks
17 admin // Nov 8, 2009 at 12:24 pm
Hi Gerry
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
18 Kees // Dec 30, 2009 at 7:09 pm
Hi Bryan.
I have been tinkering with my grey water system for about 3 years. I am now looking at filtration and am curious to know how effective your sand bin is. I think I will have the water leave my sand bin from the bottom so that it does not require water from above to flush it out. Thanks for sharing your ideas. Metta
19 Bryan // Jan 3, 2010 at 5:31 pm
Hey, I would love to hear about how your own tinkerings have been going.
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
20 Dave // Mar 26, 2010 at 9:27 am
Hi Bryan,
I am trying to design a system to filter my grey water for re use in toilet flushing,
I hope the sand filtered water will not smell,
why do you have the water go through the sand before the gravel.
Dave
21 Bryan // May 16, 2010 at 7:32 pm
Sorry for the delay in responding, Dave. Happy to share our experience.
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
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