Grey Water In Winter Time

Hi everyone!

I am finishing my Tiny House here in Montana. It's one of those portable ones a la Tumbleweed houses. And what's the biggest challenge? Electricity? NO! That's easy, with Solar panels, a few big batteries, and some used 12v car and RV appliances. Is it POOP management? No--composting is pretty straightforward. The BIG challenge is water. I designed the house to be able to freeze without damaging anything. And it's portable, which is fun. The big question though, is what do we do with the water we use? I designed the drainpipe runs to go straight with no traps, also to avoid damage during freezing. From PVC inside, I switch to fire hose outside. But what to do with the water during freezing temps? Anybody got good insight on freeze-compatible greywater systems?

Much obliged!

Hi J and welcome to Permies!

OK - so I have no experience with greywater in freezing climates, however, it seems like putting in an infiltration chamber below the frost depth and dumping the water there would work. Page 6 of this document seems to bear out this hypothesis.

Here's some more options: http://greywateraction.org/content/systems-cold-climates-including-wetlands

What kind of volume are we talking about? How many showers a week? how much laundry, if any?

Do you need a portable solution or are you parked in the same place every winter?

How much slope of the land do you have below the house to work with?

R has some great points. And here's a place to calculate how much greywater you are generating.

Thanks for the questions and answers!!

I will be living in the place alone, and plan to take about 4 60 second showers per week. I'll also be doing dishes, washing my hands, and my pee goes down the same plumbing system as the bath tub and hand washing. No laundry. Poop is dry-composted while it remains inside (to be emptied every week or so) and does not need to be part of the equation. I have a 30 gallon water tank that I am hoping to fill approximately once per week--hence the extremely short showers. Depending on how in-depth I go, I may leave the house in place permanently. Let's assume I have very little slope to work with, but that the soil is very permeable.

Some great links in the replies, I'm looking forward to studying up!

You are using less than 5gallons of water per day. I add that much water to my sage plants and it is gone in minutes. In the winter it would be different but if you move the fire hose termination location once a day or empty the bucket at a different place everyday, it will not be a big deal.

S Bengi wrote:You are using less than 5gallons of water per day. I add that much water to my sage plants and it is gone in minutes. In the winter it would be different but if you move the fire hose termination location once a day or empty the bucket at a different place everyday, it will not be a big deal.

Agreed! Just don't vent the water where it *might* freeze and present a slip hazard.

It is obvious that most who responded dont live in COLD climates. The water will freeze and build up with no perculation during the winter, because in cold climates the ground stays frozen for months at a time.

The best way to deal with the winter disposal of grey water issue is to put in a drain field similar to what they use to empty a septic tank. Since there will be no solids, the tank isnt needed. Just dig a trench below the frost line, preferably under where you would like to garden, and put in a drain line made from perforated pipe covered with gravel and protective cloth to keep it clear. Then when the weather demands it hook your grey water to go down the pipe. We have our set-up with a ball valve that we open every spring to let the grey water run onto the plants and then close every year to send it under ground under the garden area so the deep rooted plants can access it or let it return to the water table after the soil filters it.

Sky Orndoff wrote:I will be living in the place alone, and plan to take about 4 60 second showers per week. I'll also be doing dishes, washing my hands, and my pee goes down the same plumbing system as the bath tub and hand washing. No laundry.

Van Taylor wrote:The best way to deal with the winter disposal of grey water issue is to put in a drain field similar to what they use to empty a septic tank. Since there will be no solids, the tank isnt needed. Just dig a trench below the frost line, preferably under where you would like to garden, and put in a drain line made from perforated pipe covered with gravel and protective cloth to keep it clear. Then when the weather demands it hook your grey water to go down the pipe. We have our set-up with a ball valve that we open every spring to let the grey water run onto the plants and then close every year to send it under ground under the garden area so the deep rooted plants can access it or let it return to the water table after the soil filters it.

Sky originally stated that the greywater in question would include dish water (technically "dark grey water") so there would be some solids and grease that could block the holes in perf pipe over time and settle out into the gravel as well. I know in discussions with Brad Lancaster (Rainwater Harvesting for Drylands) he indicates that a solid pipe to an infiltration chamber is preferable in instances where dark grey water (and grease) may be present. So a solid pipe running to an infiltration basin below the frost line seems like a workable system.

The holes in perforated pipe are large enough that it wouldnt be a problem. We have a system exactly like I described that has been functioning with no problems since 1994. A system like you described would be more likely to clog since all contaminates would be channeled to one location rather than be dispersed over a long distance. Our drain fieled is 100 ft long. All that being said, you wouldnt want to put just any old thing down the drain just because it would fit. We have strainers in the bottom of our sinks, and anything they catch is put in the compost. Obviously you wouldnt hook up a disposal to this type of system either.

Van Taylor wrote:The holes in perforated pipe are large enough that it wouldnt be a problem. We have a system exactly like I described that has been functioning with no problems since 1994. A system like you described would be more likely to clog since all contaminates would be channeled to one location rather than be dispersed over a long distance. Our drain fieled is 100 ft long. All that being said, you wouldnt want to put just any old thing down the drain just because it would fit. We have strainers in the bottom of our sinks, and anything they catch is put in the compost. Obviously you wouldnt hook up a disposal to this type of system either.

Agreed that the holes are large and would take a long time to fill.

Agreed that you don't want to put anything down the drain just 'cause it will fit (although tempting at times) or put a garbage disposal on it (with perf pipe at least).

I guess my main concern is the grease of the dark grey water going into the system. My understanding is that it can "seal" both soils, perf pipe holes and spaces between gravel over time (albeit a long time depending upon how many people are using the system and volume of grease). Right now I have a separate system for the dark grey water coming out of my kitchen sink. I handle any greasy/oily dishes by wiping them out with a paper towel and composting it before washing it in the sink. By doing this I hope to combat both sealing the soil in the underground infiltration chamber and avoid any smells coming back up the pipe and into the house.

As for the system clogging - in my system I have 3" diameter ABS pipe running from my sink to the infiltration chamber so I don't really see it clogging. The pipe leads directly into a below ground infiltration chamber.

You seem to have a small septic system? None the less, your filtration chamber has to empty some where or it has to be cleaned. With a large drain field, the grease and particulate matter breakdown over time just like anything else organic. We have a family of 7 right now using our system, and it was 9 for years before my 2 oldest daughters moved away. The size of your pipe has nothing to do with clogging. It is your filtration. If you dont give enough area to your drain field, it will clog. By chaneling your waste to one spot it will have to either accumulate to be dealt with later, or it will clog as it overwhelms the system. By spreading out the waste, and having the holes large enough, you avoid back ups and give everything enough time to decompose. We dont make any special accomadations for greasy dishes and we have a system that works perfectly. It sounds to me like you may have over thought the problem. Thats my experiance anyway. Good luck to you and she. Van

Yep - small system - just for that one sink on a small urban lot in a tight side yard setting. The infiltration chamber is bottomless and sits on top of earth so it's not "filtering" anything per se - the water flows directly from the pipe into the ground which is covered by the infiltration chamber. I have a "fancy" plastic chamber but it could just as well be made by cutting a 55 gallon drum in half and punching some holes in it - these can be linked together for a much larger system. The chamber provides an airspace/holding area for the water to perc into the soil. The white pipe you see sticking up (top painted brown) is a cleanout. In other performances of similar systems (which like your system, have been around for a couple of decades), the biggest problem is the chamber filling up with worm castings! I'm pretty confident about this design as it has been heavily researched by people with a lot of experience in this area. And, as with all things, there are multiple ways accomplishing the same goal. And it's heartening to hear that your system has worked flawlessly since 1994 - that's a great track record. My oldest greywater system was built in 2008 - like you, I experience no problems with it.

So whatever you do, go well below the perceived frost-line.

The reason for this is that even if your system doesn't freeze solid, the cold will congeal grease that much faster. Get deep to avoid this.

The problem with most home made filtration systems is that they are prone to slime seal with anaerobic bacteria colonies. These colonies go hand and hand with grease.

Having your grey water system dump through a vermi-compost mulch box, in an insulated box under your house (consider that this will not be heated so it needs to be more insulated than your home), or in the house itself. The rich soil that is created in this box is worth the effort to retrieve, and that effort can be minimal if you design the box for this purpose. The water (filtered through window screen and landscape cloth) can then enter the ground below the box and disperse without particulate, bacteria, or grease, into the ground well below the frost.

This is a link to a worm box filter: http://ecosenseliving.files.wordpress.com/2010/01/wb-2012.pdf

wouldn't all this depend entirely on the actual temperatures in the location? I live in a cold climate - north of UK and we regulary get freezing but not arctic permafrost type cold - we drain bathwater straight down into waterbutts - with a diverter to fill into garden irrigation via mocrobore plastic irrigation tubing. hasn't frozen yet in years. usually the water is warm. so unless you have some serious cold it shouldn't freeze unless the end destination of the water is going to collect in a puddle or something like. then it will freeze.
you could also wash your pots and dispose of the water seperatly.

Agreed. It would totally depend on what your frost level is, and, like I said, you just need to be below it. Where I live (and in Montana where the OP is) there is no permafrost, but frost does penetrate to a depth into the soil during the winter, and all waterworks have to be below it to prevent freezing, particularly the outlet since water can accumulate there. Your latitude being what it is is also moderated greatly be being on an island. Montana has a continental cold winter.

If you want an extremely low-tech system I still think the drain out back would work fine, as long as you have enough space and don't have nosy neighbors or inspectors.

Our greywater flows out of a buried pipe about 30 feet and then dumps into a small surface canal that waters willow and other trees in summer. Sure, yeah, it freezes all over the place in winter, but then in spring it slowly melts and sinks in long before we start needing to use that land.

This type of system would totally not pass any kind of inspection in the US but if you just want to do something easy for the first year or two before you invest in a long term solution, I don't think it's so bad.

Enjoying the thread, I am researching how to build a grey water system for 20,000 gallons a month at peak usage. It will be designed for a cold temperate climate 5a-5b and will not include a cold frame/glass house. So the best idea I have seen is the shallow and deep leach fields one for summer and one for winter.

I have a link to a worm system and was wondering if this is similar to the one Roberto was talking about http://permaculturenews.org/2013/09/18/grey-water-grease-trap-pri-maungaraeeda-sunshine-coast-australia/

More Worm filter blog

http://velacreations.com/blog/404-grey-water-filter.html

According to what I've read a constructed wetland type system works reasonably well in the winter here. Unfortunately they're still essentially illegal in my state despite the research developed at the U. of M. Maybe they had more problems a few years after construction?

I've found out that in order to legally build one I'd need to buy a special permit for I forget, five or ten thousand dollars, and then hire a contractor with a higher level license than the local guys and even get an inspector with a higher leveled license than the regular county official who oversees septic systems. It's pretty ridiculous when the contractors tell me even the approved designs typically don't function as well or as long as claimed.

here's one link and I know there's lot's more good info out there from when I was researching this.
constructed wetland pre-treatment

Here is our simple surface discharge greywater system. As you can see, we have a good cold winter but also an extremely arid climate. Most January nights go down to -20 to -25C, -5 to -10F. We bury pipes 2 or 3 feet deep to prevent freezing.

We have a minimum of 40 people living here at all times, going up to over a hundred for a week or two at a time several times a year. These systems have been in use for 15 years. In this photo from Feb 9 2014, the ice has already started to melt and soak into the ground; in mid-January, the areas of greywater ice were much larger.

We simply run the greywater pipes underground for a distance away from the buildings, and then dump them on the surface. In summer the greywater is in the canals for trees (willows, poplars, apples, apricots, and a pear). In winter sometimes we divert the canal onto the empty garden (as in this photo). Art Ludwig, author of the excellent greywater book and website, says that topsoil is the simplest way to process greywater -- it has more air and organisms than the deep soil in a drainage field. And luckily in India we are not hampered by regulations. If you bury perforated pipes shallow enough to be accessed by tree roots and soil organisms, the holes and pipes get clogged by roots. We find that if our clean supply pipes have even a tiny pinhole, the whole pipe gets clogged by a huge thick snake made of willow and poplar roots.

Our bathing / clothes-washing greywater has plenty of soap, detergent, who-knows-what hair products (gick), and probably some undeclared urine. The kitchen greywater has bits of food and some vegetable oil, but not much animal fat that might congeal. The soil along the kitchen canal is not visibly greasy: it is distinctly gorgeous black soil speckled with egg shell bits. The soil around the bathing greywater canals is the same sandy color as the rest of the area, though the vegetative growth is much more abundant. In non-frozen seasons, the kitchen greywater stinks and looks yucky up close, but since it's away from the houses it doesn't matter except when ripe fruit wants to drop in it. The bathroom greywater can get that grey soapy look and smell but it's not too strong. Both soak in and obviously get digested nicely by the soil. When we rotate the greywater between different canals every few days, today's dry canal appears and smells normal.

Art Ludwig also recommends mulch basins, which I think sound like an excellent idea and would eliminate the visible surface yuckiness. But here where biomass is in short supply, topsoil works well.

Have a look at Wendy Howard's system in Portugal on https://permies.com/t/17877/composting-toilet/Humanure-flushing-toilets-worm-farms

Straightforward humanure filter system for flush toilets.

Pamela mentioned a 50 gal. graywater tank that is pumped when it fills to a certain level. Care should be taken when storing graywater. It will become blackwater in a matter of hours. Significant filtering is required to store for any significant time.

Tim, putting a filter or pumping it out right away is not a problem that is already done but tell me something. This is water from a washing machine only. Products used are green products. No grease, food etc. There is nothing from a toilet either Nothing. So how does grey water turn into black water and does a filter help?

Pamela,
I'm not a biologist or chemist, but what I've been told is that there is a chemical/biological change that will happen to graywater over a short period of time. Even if I didn't mind dumping stinky graywater on a field, I'd rather not promote a smelly operation. My perfect design would first filter the graywater into an interior wetland tank, and then dump the "filtered" water at will.

Pamela, as the gray water sits, it becomes anoxic. The sulphate reducing clostridia bacteria that thrive in anoxic conditions make the liquid and sludges black (like estuary mud for example). Hence the change in the name. If you filter it through a constructed wetland or reed bed, both grey and black are improved. Let me know if you need help with sizing etc.