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Grey water, sand filters and detergents?

 
Trevor Miller
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Just curious if anyone can answer this but, I plan to minimize my use of strong detergents like bleach and various cleaners but sometimes it's unavoidable. I want to create a grey water system for irrigation and need to have it filtered for use in the soil without killing everything in it. Will a filter, say gravel bottom, with a hefty fine sand layer, and charcoal and green sand on top filter out these various detergents?
 
Bryant RedHawk
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strong detergents contain phosphates, which do not break down readily.
Chlorine (bleach) is also not easy to break down but it will bond with some minerals making them inaccessible to plants until the bacteria and mycology can get to work on those.
We use some bleach when needed and it goes through a grassy sand bed that is full of bacteria and fungi before it gets to the garden area, no problem but if we used a phosphate detergent I would have to add filters and distance to the filter bed.

I would recommend you use a sand filter first followed by a charcoal filter then the waste water can go through a gray water reed bed that contains fungi.

I'm curious, why you need such harsh chemical cleaners?
If it is greasy clothes, Dawn dish soap is a good choice since it is already biodegradable. Zote is another easy on the environment soap and many homemade cleaners make use of it in their formulation.
There are many formulas for homemade cleaners on the internet and at MEN or Cappers or Grit that you can make up and use without worry.

Borax is a great cleaner that is biodegradable plus it has many uses other than cleaning.
It will keep termites out of wood that has been soaked in a 20% solution or you can layer dirt and borax when planting wood poles and that will keep termites away from your poles.
Baking soda is another multi purpose product that is bio friendly.
 
Trevor Miller
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Mostly it will be bleach for various tasks, mainly the kitchen and sanitizing the well and plumbing periodically. Maybe an oven cleaner here and there. I figured charcoal would be the most effective. It'll be a rare occurrence but it'd be nice to be set up for my entire system to absorb rather than collecting that water and taking it off site myself if I can avoid it.
 
Wyatt Barnes
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Shock water from a well and the house piping should be flushed outside onto a lawn/green area through an outside tap and hose. I have not known it to harm a lawn maybe due to dilution. Other than that there should be very little volume of harsh water so most systems should easily absorb it without adverse effects.
 
Tim Nam
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Location: Arcata, CA zone 9b
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we are not living on our land yet and collect gray (dish) water in buckets for our nascent veggie garden and potted tree collection (to go into swale mounds later) anyway, i scored a hot tub/pool filter from a friend, basically a big bucket with a threaded fitting in the bottom. i think its actually a sand filter, but i just dug my own sand from the beach and put gravel on top. oh, i stuffed some old pantyhose into the back of the valve i fitted into the bottom.  the flow is all gravity driven. during the rainy season i ran excess shed roof water which flushed it out, but now i'm running the dish water through it. pH tests indicate normal levels for plants 6.5 ish and so far so good. i don't want to do this indefinitely of course, but for now its a surviving solution. i think just having a container with a bottom drain is enough to get most of the detergent, which i assume floats on top (with any grease) and adheres to the gravel sand on top rather than flowing through.  also we're using the brand seventh generation dish soap which i guess is more eco friendly than most. i think i just need to get the greywater oasis book and set up a proper living filter. but in the meantime, we're keeping our plants green and growing and always keeping an eye out for rain. why are we using the sand filter? good question, and i'm not sure its even necessary. it slightly clarifies the water but does not deodorize it. the big stuff we could get with a sieve/net and the little stuff is likely plant food/micro kitchen waste...i don't know, i guess its mostly to get the separation of floaties (fats and soaps) but also to feel better about giving the plants cleaner water. just a bit on our situation.

 
Cristo Balete
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Location: In the woods, West Coast USA
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Grey water reed beds do a great job of cleaning soaps out of grey water.    There are lots of pond plants that can coexist in a reed bed filter system.

I would definitely try to use lemon peels soaked in a bottle of white vinegar for a sanitizing cleanser.  Just don't use it on marble.  Baking soda is also a great cleaner and tooth polish.  Salt and lemon juice cleans and disinfects wooden cutting boards.   Washing soda mixed with borax and a couple squirts of Castillian soap (Dr. Bronner's peppermint soap) does laundry.  His pure soap does a lot of household cleanup.  Just look up natural cleaners and you'll see all sorts of good substitutes for evil bleach and detergent.

Bleach and detergents are very bad for the environment and for us.  I haven't used them in years and don't have any issues with bacteria.

Here are pictures and a discussion of reed bed systems on this website:

http://www.permies.com/t/39474/grey-water/Grey-water-reed-bed-system
 
Mick Fisch
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Sometimes there things you just need to use bleach.  Our well water gets to smelling sulpherous after a while and we have to shock it every few months.  It takes about 5 gallons of bleach to handle our well and two 50 gallon hot water tanks + pipes.  We take advantage of the nastiness and dump the contaminated water where we don't want things growing anyway.  We use our gravel driveway. 

I know with normal chlorinated tapwater, if you let it set open for a day or two the chlorine goes into the air and you can now use the water in fish tanks without killing the fish.  I think that bleach water, while a lot stronger, would loose a lot of it's nastiness if it can ventilate a few days before you dump it.  I realize this is usually not possible, but it's something to keep in mind. 

The solution to pollution is dilution. Flushing your system with a lot more water would certainly help (maybe do it during a big 2 day storm).  Your gallon of bleach becomes a lot less significant if it's mixed with a hundred thousand gallons of rainwater (not an unreasonable amount if you have an acre or two of land draining into an area.
 
Carol Ann Chase
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Location: United States
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We are building a new house and I am influencing my husband with principles I have learned in a permaculture design course I took last year. I believe he is ready to sign off on installing a grey water system. I am working with a permaculture greywater expert here in Colorado coloradogreywater.com . Colorado has recently adopted greywater practices as a state, but counties are not yet up to speed on the processes and permits yet. My husband is going to ask our county building department if they would be interested in using our desired system as a test case. If not, we may have to have a less than legal greywater system ;p I really appreciate the comments and the wealth of knowledge on this blog because I have lots to learn about detergents and cleaners that will be compatible to my food forest trees and plants.
 
Thekla McDaniels
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I have a septic system into which flows all the household grey and black water, don't feel able to retrofit to re use the grey water. 

In the desert, I cool with a swamp cooler.  The salts build up from so much very clean water getting evaporated, so I had a purge pump installed.  That darn thing!  There is no option for how often it purges.  IMO once a week would be about right, because it is very clean, non alkaline primarily first use snow melt water getting used in the swamp cooler.  The purge function runs every 8 hours!  IMO that's often enough you could be running sea water on the pads, but that's the only kind of purge pump.  When it purges, it rinses all the water out, with accumulated salts.  I can hear it, and though the purge pump says it is only going to use about 8-12 gallons, it's more.

The standard is to run a hose from the cooler to a plumbing vent to pour all that essentially fresh water down into the septic system (my house) or the sewer ( my friends house).  I run that hose to an outdoor bath tub.  The dogs drink from it, I carry it to the goats, I dip out of it to water any plants I hand water.  Sometimes I get in to cool off.  If I have muddy clothes I dip out of it, and rinse my clothes in the bucket of it, then water the plants, or the dry spot on the lawn...  If the level gets down because I have not run the swamp cooler, then I can wash the dog in the tub, then drain the tub and clear out the stuff the falls in settles, algae that grows.  I pull the plug and water the lawn with the water and sludge.

It's not much I know, but it's what I have done to re use that water as much as I can.  My friends have fashioned a drip system, a hose carrying the purge water to potted plants and their vegetable garden.
 
Tim Nam
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Location: Arcata, CA zone 9b
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our (beach) sand filter is clogging...checked out Art Ludwig's book from the public library, thanks humboldt public library!
 
Rebecca Norman
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At our school, the greywater from the bathing block and from the kitchen go directly out to small canals running past trees. We don't avoid any kind of detergent or soap, though I have managed to prevent use of drain cleaners and bathroom cleaners so far. But there are pretty large amounts of standard commercial clothes detergents like Tide, and who-the-hell-knows what kind of "products" our students use on their bodies and hair. Some of them have funny colored patches of hair sometimes so evidently they do use hair bleach and dye from time to time, and I know that most of them use various foul chemical sunscreens and even whiteners.

The willow trees have been thriving for 20 years on this diet. The trees that receive the bathing block greywater are much bigger than the other trees on our campus, probably because they get so much more frequent water than the others. I think you'll find that as long as you are using enough water so that things are diluted, then a lot of products will be dealt with by a good greywater system's ecosystem.

Art Ludwig's book is wonderful and you should get it ASAP. I don't have it in front of me right now, but I don't think sand filters come out as desirable in that book (somebody please correct me if I'm wrong). My memory of the book is that he prefers mulch basins around trees or plants, because the water is kept fairly shallow and thus aerobic, and the organic matter of the mulch (typically wood chips) grabs the nutrients in the greywater and becomes compost.

Ludwig points out that putting greywater onto topsoil that contains organic matter and living things is one of the best and simplest methods, since the topsoil teems with a rich ecosystem of aerobic organisms. That's what seems to be operating at our school. But it might not be legal in your region and/or liked by you, since you do see some slightly smelly cloudy water on the surface before it soaks in. So Ludwig's mulch basins are probably a better bet.

 
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