Instructables

Filter your Laundry Graywater with Marsh Plants!

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A while back, I started using greywater, waste water from my clothes washer, to flush my toilet. The system works well, and saves TONS of water, but I still wanted some way to filter the water first, preferably with a biological system.

I keep a large aquarium, and I also compost, so I thought that some of those same principles could be applied in my laundry room.

So, I converted my laundry tub into a constructed wetland!

To get  started, you will need:
Space next to your washer
A laundry tub
Drain Pipe
Hole Saw/Drill
Sand, pebbles, stone, dirt
Landscaping fabric
Wetland Plants
Your wife's permission!
 
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Step 1: Work Area - Tub Space

To get started, find the space next to your clothes washer.
In this space, I originally had a wash tub, but replaced it with a large barrel to hold laundry water. The original water-lines and drain are still there.

In this case, we are NOT going to use the drain, but rather, install a new pipe that leads to a water storage unit.

Measure where the center of the drain is on the laundry tub, and then mark that same distance on the floor. Drill a hole through the floor there (making sure a floor crossmember isn't directly below) with a 2" hole saw.

Slide a drain pipe through the hole. If you have a full basement, you can slide the pipe in from below later. If you only have a crawlspace, like I do, you will have to put a short piece of pipe through BEFORE you install the laundry tub.
 

Step 2: Install the wash tub

Put the wash tub back in next to the washer.

Hook up the water lines to the faucet.

Glue a threaded connector onto the end of the new drain pipe, so that it can thread directly to the washtub drain. 

Thread the new pipe into the bottom of the wash tub.
allindsay2 years ago
Makes me wish I had a washer to experiment with this idea, great job.
sffitzge3 years ago
What if you simply filtered the water to use again in your washing machine? It's hard to tell if the water is clean enough but I imagine the vegetation and the fabric clean out any particulates you may have from washing really really dirty clothes and other than that it would just be clean water with maybe a hint of soap.

then you could just use the same water over and over and over again for washing clothes, or if you wanted to get really fancy you could use a valve or something and use the water for the toilet occasionally (when you wanted to change out the water)

either way awesome idea
I'm curious to know if you have had a mosquito problem.
bennelson (author)  jclemensberger3 years ago
No. No mosquitos.

There was one time when I was sort of redoing the plants, and I just had some landscaping fabric in there. It would get wet and not dry. I got fruit flys for a few days because of that.

With the regular setup of plants over sand-filter, everything is fine.
Splaxx4 years ago
For the threaded port on the side have you thought of modding the plug to allow the Pex pipe to go through it?
bennelson (author)  Splaxx4 years ago
I could do that, but it is just so easy to simply put the pex tubing over the top.

The other odd thing is that the drain plug really isn't all the way to the bottom, I can actually get the tube lower than it would be connected to the drain.

That drain plug might make a good spot for an overflow. Instead of running a pipe straight out from it, I would put an elbow on there and have pipe go up to just short of the top of the  greywater tank, then over and out.

I would just need to make sure there is an air break so that it wouldn't siphon ALL the water out if the tank overflowed.
bennelson (author)  bennelson3 years ago
5/4/2011

I did end up doing exactly what I said above.

One time, my wife was doing laundry and not paying attention at all, and flooded the crawspace a bit...

I put a PVC pipe going into the drain port on the side of the tank. That splits up to a manual drain with a valve on it, and output to the pump, and a pipe that goes vertically up to just shy of the top of the tank, with a tee that's open to the air to prevent siphoning.

Should the tank get too full ( too many loads of laundry in a row for example... ) it will start going out the overflow drain before it would run over the rim of the container.

I have still not added any sort of "automatic filling valve" to the system. The single biggest idea of this system is to save water, and keep it as simple and passive as possible.

Should the toilet get flushed too many times compared to how much laundry we have done, the water level can drop too low. On the rare occasions that it does, I just run a little water from the laundry tub faucet straight down into the graywater tank...... Then I notice it was about time to do a load of laundry anyways.....
8bit4 years ago
How are the plants fairing with soapy water? 
bennelson (author)  8bit4 years ago
 Seems ok so far. I haven't had it set up like this too long yet though.
I believe soaps are typically high in phosphorus, which the plants should tolerate pretty well (this is what causes algal blooms). But the plants are really there to provide microenvironments with high oxygen around the roots. These microenvironments and the ones that form around and in between the pebbles provide oxygen for the aerobic bacteria that do the actual work of breaking down the greywater.
bennelson (author)  QuestionConvenience3 years ago
I use an eco-friendly, all-natural soap (locally made!) and the plants have no problem with it.

As QuestionConvenience just stated, what this is all really about is setting up the right environment for plants and microrganisms to thrive to help prevent the formation of bad bacteria and keep particulate matter out of my pump.

I'm just trying to imitate the way that nature uses wetlands to clean and filter water.
So far, it's been working very well.
bennelson (author) 4 years ago
 Right now, the cat-tails are over four feet tall!

I measured, and when they were shooting up, the grew faster than an inch a day!

The marsh grass isn't doing as well. At first, it shot right up, and looked green and healthy. But then it flopped over and looks to be turning yellow.

Other plants are now growing in there as well. I am happy that these "weeds" seem to be springing right up!

The water in the holding tub stays very clean and clear-looking.
Do they need much light? Usually a laundry room doesn't have much.
bennelson (author)  Robnelson3 years ago
My laundry room only gets good light late in the day.

I did later replace the marsh plants with "spider plants" and some other plants that grow well in lower light.

I also installed an LED strip light under the upper cabinet, and had that on a timer. It takes almost no electricity, but still gives the plants some light. It's mostly just for winter use when the days are so short.
richarpo3 years ago
Is bleach a harsh chemical? In the concentrations used for laundry, the plants may not mind it that much.
bennelson (author)  richarpo3 years ago
I get itchy skin if bleach is used on my clothes.
Same with chlorine pools.

Half the problem is that people tend to use TOO MUCH of household chemicals.

For me, it's just easier to not use them at all.
andy19174 years ago
I love it !!!!!!! I do have a question though . I have been tryingto come up with a simila way t filter my grey water for watering our garden. This woudl be a large scale filtering as my garden is 3 acres. We use eco friendly soaps (challeneg to convert wife) for awhile now , but still at times use bleach. Do you have any advice for someone needing to double check themselves or add a measure of safety to a large water collection system? My ultimate goal is to have a system in place that wil capture all rainwater and grey water to use for watering my garden. The only thing hiting sewer would be toilet water . ANy help greatly apreciatted.
bennelson (author)  andy19174 years ago
I would imagine that an outdoor "constructed wetland" would fit the bill. Check out any and all books by Art Ludwig. He has books on graywater AND constructing cisterns for rainwater holding and irrigation. Also, do a web search for Graywater Guerrillas and visit http://www.greywateraction.org/ Hope that helps! -Ben
thanks alot for your help
meralgia4 years ago
Nice idea!  Is there a way to put a sensor on your tub in the crawlspace to ensure that 1) it won't overflow and 2) there is water in the tub to pump out before you flush the toilet?  If there isn't enough water in the tub to pump out, does the pump sense that and send well water to the toilet?
bennelson (author)  meralgia4 years ago
 I'm working on making a "low water sensor" to alert us when there will soon not be enough water and it's time to throw in another load of laundry.

When there isn't enough water, and the pump runs, it sounds different. I can just run the faucet, and water runs down into the tub, and pumps from there.
You also could doone of two things. option one: you could use a simple float valve as backup that would use tap water to makeup the level in a case say you were on vacation. Second option: if a simple noise maker is needed you could use a HVAC water limit switch . These are used in catch paints under HVAC units . This could easily be added as a audilble alarm.
bigme4 years ago
Very cool, how many gallons of water does a typical load of laundry use with your front load machine? We tend to do all our laundry in one day rather than troughout the week, I wonder if that would flood out the marsh. I am using a FL maytag that I got free (needed a simple repair) and I was impressed with how little water it used in a standard load cycle!
bennelson (author)  bigme4 years ago
 It looks like mine uses about 20 gallons per load. Laundry machines never seem to have their water use listed anywhere. Not long ago, I went to an appliance store, and not a SINGLE machine listed how much water it used on the machine, in any literature, or on their web sites!

The first load of laundry I did with this machine, I just lined up 5-gallon buckets to see how many would get filled. It was just over four, but not every bucket was filled to the tippy top. Somewhere around 20 gallons then.
washer_buckets.jpg
I was also shocked at how much of a secret the amount of water used appears to be.  I have a Kenmore top loader, not very old but an old school design.  I used a 75L garbage pail and a load on the "large" setting filled it 2.5 times (180L) to be exact.  Thats 47us Gal. for our friends in the US.  If I had known it used this much water I would have ponied up the extra cash for a front load machine.
nolte9194 years ago
Very neat idea.

You might have a small mistake in step 6.  You have a link that says www.ecoprojecteer.net but actually points to this very instructable.
bennelson (author)  nolte9194 years ago
 Ooops. My bad. Thanks for noticing. I fixed the link.
Ecoprojecteer is my ecological home projects blog. I just started it, so there's not much yet, but I am adding to it water conservation, solar hot water, and solar PV project.s
 Eco Cool!