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Can laundry greywater be used safely in a garden?  RSS feed

 
gardener
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You guys. I am REALLY excited. Since it's been one heck of an El Nino spring, even here in the mountains, I'm actually creating my outdoor laundry space now. YES.

Since we rent, nothing can be permanent, but basically I'll have a big outdoor sink I'll be running a garden hose to, a washtub on a table for rinsing, a wringer with bucket, and of course, 4 20 ft strands of glorious clothesline.

What I'd really like to do is rig up a greywater catchment system for the water when I'm done with the laundry, but I want to use that water somewhere, like in my garden.

Here's the thing: that water will have soap in it, and since we cloth diaper, one load every other day will be dirty diaper water. Also, my husband is a mechanic, and brings home all manner of oil and grease on his clothes.

I'm thinking this is my chance to experiment with an inline greywater filtration system, but I'm wondering, how far does that filtration really go? Will a successive media filter with carbon be enough, or do we need to consider something more along the lines of a Berkey?

I use Planet 2x Ultra HE laundry detergent in my machine, and homemade laundry soap with castile soap and washing soda, and the occasional addition of peroxide. It's all technically biodegradable, but can the plants that we eat take that level of chemical-ness? It's not ideal, but I gotta get our clothes clean, and I'd really like to reuse that water if I can.
 
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I stopped using soaps and detergents a few years ago... My body didn't fall apart. My clothes still get clean in the laundry.

I use a bit of soap still on mechanical grease, but that's about it.
 
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Can you put in a diverter? Send the diapers and mechanical grease towards ornamentals and the rest into the regular garden? Better yet, have the ornamentals uphill from the edibles.
 
Destiny Hagest
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Joseph Lofthouse wrote:
I stopped using soaps and detergents a few years ago... My body didn't fall apart. My clothes still get clean in the laundry.

I use a bit of soap still on mechanical grease, but that's about it.



I can see that being fine, with the exception of mechanical grease and cloth diapers - bacteria buildup there is really serious. My baby's never gotten a rash, you have to really be on top of it with the diapers.

Casie Becker wrote:Can you put in a diverter? Send the diapers and mechanical grease towards ornamentals and the rest into the regular garden? Better yet, have the ornamentals uphill from the edibles.



I actually don't really have any ornamentals, just some native trees. I can always dump the diaper/grease wash water into a nearby runoff and let the local water table system filter it out and balance the bacteria, but what I'm really concerned about is the effects of the soaps on my plants. They're really mild, but they're still detergents
 
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...and the occasional addition of peroxide.


Don't worry about the peroxide: Water is H2O, and peroxide is H2O2 - water with an extra oxygen particle. Rain that passes through the ozone layer picks up an extra O particle, becoming peroxide, which 'disinfects' the air as it falls to earth - ever notice how the air smells so clean after a good rainfall? It is a disinfectant (the added oxygen oxidizes bacteria -kills it, and gets consumed in the process). 'Spent' peroxide is essentially water.

(Side note: peroxide is the 'OXY' in Oxyclean products.)
 
Destiny Hagest
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Very true John, I didn't even think of that, that's very reassuring!

I suppose all I really need to worry about is my laundry additives. I'm going to dig out my greywater recycling book again tonight, but I just don't remember reading anything about this particular issue.
 
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so is that a yes it can be used, as long as your not using normal laundry detergent? or no it can't be? Kind of confusing. We rent too & I don't know how the new landlord would feel about us altering things. His dad (the original landlord) already had the grey water (kitchen sink, dishwasher, wash machine) separated from the septic, why he didn't separate the shower & bath tub from it too is beyond me. He told me one time that the grey water would fill up the septic too fast (& I'm thinking so would a tub & shower) & the chemicals from the dish soap & laundry soap will kill the bacteria in the septic (& I'm thinking, so would the soap for bubbles & washing ourselves). Ideally, i'd like to re-route the tub & shower water to the grey water pipe, but i think that'd be a huge mess to pipe into (for some reason the kitchen & washer, etc. pipe goes from the east side of the house back to the west of the house (at least 1/2 way back of the house) & then out to the north before going back to the east & at some point going north again to the field. And drains openly.....
I'd like to change the piping if we get our own place that way we could divert all grey water out of the septic & filter it naturally (cat tails & other similar plants work great on filtering such water)& be able to use it on the garden or even the yard, but chances of convincing my husband to do something like that will be next to impossible, UNLESS we have to do repairs on said pipes
I did not marry an "adventurous" man when it comes to such "changes"
 
Destiny Hagest
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Alli Sheldon wrote:so is that a yes it can be used, as long as your not using normal laundry detergent? or no it can't be? Kind of confusing.



It's really unclear to me too, but I'm guessing no, it can't be. The way I see it, I would't put it on my plants, so I'm sure it's not good for them. I use very specific detergent that's extremely eco friendly and still gets diapers clean, but even then, I'd feel funny about it. I'm not sure what the solution is to this problem.
 
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John Polk wrote:

...and the occasional addition of peroxide.


Don't worry about the peroxide: Water is H2O, and peroxide is H2O2 - water with an extra oxygen particle. Rain that passes through the ozone layer picks up an extra O particle, becoming peroxide, which 'disinfects' the air as it falls to earth - ever notice how the air smells so clean after a good rainfall? It is a disinfectant (the added oxygen oxidizes bacteria -kills it, and gets consumed in the process). 'Spent' peroxide is essentially water.

(Side note: peroxide is the 'OXY' in Oxyclean products.)



Um. Clouds are concentrated in the troposphere. The ozone layer is in the stratosphere (above the troposphere). There is some hydrogen peroxide in rainwater, but in tiny quantities. The source of that clean smell is a combination of ozone (also toxic), geosmin, a chemical produced during sporulation of ascomycetes, and the chemicals excreted on the leaves of certain plants.

Much would depend on concentrations. The body produces small quantities of formaldehyde, but you wouldn't want to drink it. Hydrogen peroxide is also highly toxic, and will have an impact in the soil in your garden. A little is not likely to do a lot of damage, but too much would be another matter.

I suggest running the laundry greywater through the same system that you would use for any other sensible greywater treatment, but go easy on detergents. Most detergents destroy chitin (the stuff that makes up invertebrate carapaces, among other things).
 
Alli Sheldon
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Destiny Hagest wrote:

Alli Sheldon wrote:so is that a yes it can be used, as long as your not using normal laundry detergent? or no it can't be? Kind of confusing.



It's really unclear to me too, but I'm guessing no, it can't be. The way I see it, I would't put it on my plants, so I'm sure it's not good for them. I use very specific detergent that's extremely eco friendly and still gets diapers clean, but even then, I'd feel funny about it. I'm not sure what the solution is to this problem.



Yeah, that's what i'm thinking too. I mean......when i was taking some Ag classes at my local college (years ago) we did a tour of a "pond" area on our campus where they created a (BIG) area where they used various plants to "filter" water to get rid of sediment, toxins & a variety of things (I forget now what all this other group was doing) but they had great success, but also wasn't grey water that they were filtering. I've read on other sites that filtered grey water & had it going off in one area to be pumped elsewhere. But looking at the run off from our grey water (which includes some mighty gross stuff from the sink) & what comes out when we have had to unplug the drain (its either due to a broken pipe with roots growing into it or way too many elbows--which is my thought) I can't picture using this water without a big huge area to let the water to gather & have a lot of water loving plants (like cattails, etc) that also are known for filtering water before using it & that's not going to be a small task or a quick one to accomplish & definitely not one most people would be able to set up on a small place. I know we can't even though we've got a good size are that we could create a pond, getting the landlord to use their backhoe to create a good size pond for us for this to be a useful thing, just isn't a possibility.... I could use a different source of laundry soap, but i haven't found anything that works with our very hard water to get our clothes clean yet. I guess i'll go do some more searching on this topic to see if i can find something more specific on this topic
 
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I would like to reinvigorate this discussion.

I have recently built a Hugelkultur mound and planted a variety of vegetables.  I irrigate (sprinkler) the mound from above with well water or rain water, and at the bottom of the mound is a pool that is directly fed from a Greywater system.  The Greywater originates from my home's sink drains, tub drains, dish washer and laundry washer.  My wife buys biodegradable laundry detergent, but she sometimes uses bleach.  The dish washer detergent is just commonly available products from the local grocery (I have no idea what it is!)

The pool of Greywater is about 14 inches deep, and filled with logs and branches.  Above the logs is another 16 inches of soil, consisting of layers of wood chips, compost, top soil, cow manure, and garden soil.  The plants will need to put down their roots about 16 inches to actually get into the Greywater, and the irrigation (15 minutes 3 times each day) may somewhat relieve the plants of the need to do so except during the hottest part of the summer.  However, the whole point of Hugelkultur is to create a wet sponge that can nourish the mound from below.  I probably should not need to irrigate from above unless we are in a drought season.  Right?

I have mentioned this concern on several other forums ( https://permies.com/t/68885/Unnatural-Fear-Gray-Water-Systems#705532 ) and ( https://permies.com/t/64963/Backup-watering-system#630200 ) but have not gotten any answers.

Can you help me assess the risks?

I prefer not to learn this lesson the hard way.  I would prefer to not poison my family with fresh vegetables that are tainted.

I am trying to plant veggies alongside friendly companions, but this is my first attempt at the combination of Hugelkultur, Keyhole Gardening, and French Intensive Gardening.  I have a lot to learn.

I have attached a picture of my Companion Planting Map.  The Carrots will likely reach down into the soil farther than the other plants.

Your help will be greatly appreciated!!

KeyholeMap1.jpg
[Thumbnail for KeyholeMap1.jpg]
 
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Can you help me assess the risks?

I prefer not to learn this lesson the hard way.  I would prefer to not poison my family with fresh vegetables that are tainted.




Phillip, maybe if you looked at the ingredients listed for all the products that go into your grey water and list those maybe someone could answer your question.

   My wife buys biodegradable laundry detergent, but she sometimes uses bleach.  The dish washer detergent is just commonly available products from the local grocery (I have no idea what it is!)



Starting a new thread rather than commenting on an existing one might help.


Here is a comment from one thread:

what people call "soap" today is actually a detergent. Many of these contain sodium in their chemicals which can wreak havoc on soil structure and create alkaline conditions.




https://permies.com/t/7883/Greywater-soil-acidity
 
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Destiny, if you don't have room for a pond, what would you think of a greywater trench system?

This would consist of digging a trench somewhere between your greywater outlet and your garden, lining said trench with something like EPDM, and putting baffles in an alternating pattern from the sides of the trench, such that the water is required to zig-zag through the trench, increasing effective surface area. Then "socks" or other fabric retaining structures a little more than the length of the baffles can be made and installed to hang off either side of each baffle, in the manner of saddlebags, and seeded with aquatic filtration plants. A solar-powered air pump could be used to boost the level of oxygen in the trench as well.

Another version of this construct would involve a double-width trench with a middle board, but with an opening on either end of said middle board, forming a zig-zagging looped watercourse, such that a pump could be used to induce constant movement of greywater through the system.

Phillip, I would suggest the same course of action, of a variation upon it, for your greywater woes. I think oxygen and living aquatic vegetation is necessary.

I am also going to suggest that you look at this: List of companion plants.

Some of the plants that you want to plant next to eachother look like they might inhibit eachothers' growth. I would look to the Three Sisters model to rearrange the positioning of your beans and curcurbits with your corn, for starters.

-CK
 
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Phillip, the biggest issues that I'm aware of with using grey water are the high levels of phosphorus in the detergents and the fact that the ecofriendly ones mostly operate by creating an extremely alkaline solution. So you would be dumping out alkaline water with lots of phosphorus in it. Phosphorus can be hard on fungi and alkalinity isn't always preferred, although both of these could be to your benefit in the right situation. The only grey water system I have seen up close and personal went to a settling tank and then out to a small pond that had ornamental stuff growing all around it and then essentially trickled/seeped further down slope into the garden area. It wasn't directly used to irrigate the garden but probably added to the soil moisture.
 
Phillip Stuckemeyer
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I am continuing to read up on the issue.  It seems that I might be OK since the greywater from my system enters the Hugel mound by underground pipe from below. (You can see a picture of my system here:   https://permies.com/t/68885/Unnatural-Fear-Gray-Water-Systems#705495 )  I am watering the plants from above with well water or rain water.  So the greywater never directly touches the vegetables (with the possible exception of the carrots!) so the risk of contamination is non-existent.  I will need to avoid potatoes, carrots, onions, radishes, and anything that grows under the ground (actually I will just need to grow then in a more traditional plot) although the roots would need to reach down no less than 16 inches to touch the greywater pool.  I am encouraged.  Thanks to all for advancing the discussion!!
 
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