greywater use

[mountaindweller]

As it's getting dryer we have all our downpipes (shower, bath, laundry and sink) fitted with wastewater diverters. (In Australia most houses sit on stumps so that the pipes are easily accessible).
Our vegetable garden sits close to the house and my plan is to make a ditch to funnel the water into the garden. (If I would know how to insert a pdf image it would be here).
The greywater outlet is slightly uphill and my plan is to make a ditch all along the hill facing side of the vegetable garden. This ditch will be either what permaculturists call a swale which is a ditch planted with shrubs and small trees or a constructed wetland that means that the ditch would be filled with water loving plants. In both plans the water should be filtered by the plants and slowly seep into the garden.
How would this affect the soil? We will have to connect a simple grease trap for the kitchen. There would be soap, some green laundry liquid, dishwashing detergent, shampoo and toothpaste. There are four of us and I think that the kids as soon as they are teenagers shower more than once a week. For the washing machine I need to buy a drum were the water can cool down a bit and then manually releasing the water.
I think there will be around 140 liters per day.

[circumspice]

You could also make a simple single or double chamber receiving/settling tank that is similar to a septic tank. A landlord I had years ago made a greywater system like that to water his berry brambles. It worked very well. He made the tank out of common cinder blocks & waterproofed it, then ran a drain line to a drainage field line. I never had to water the berries ever again. He did all the work himself.

[steev]

Good for you! The only concerns should be what you put into the system; no bad chemicals, no bad problems. As for your teens, your gardens will benefit from their insecurity; that's a win-win!

[mountaindweller]

We don't use bad chemicals but soap is alkaline. What does it do long term to the soil?
And we cook fatty so we will have to do something with the kitchen water.
What do you think is better, the option planting the ditch with trees/shrubs or building a more pond like system?

[templeton]

MD,
a couple of ideas.
My shower water goes straight on the garden to water my citrus. We use sorbelene and some shampoo rather than soap, but i have noticed no detrimental effects apart from a bit of scummy mark on the grass where the outlet is.

I looked into this a few years ago, and grey water onto veges is only really a problem if you have kids - E. coli counts are really low in shower and bath water in households without young children.

My clothes washing water goes straight on the garden too - we use green liquid rather than powders.

If you have grey water sitting around in tanks or ponds, I think you might potentially get nasty organism build up. I would go with a straight swale onto the garden.
If you want to maximize the water to the garden, don't put in trees and shrubs in the swale - they will use up heaps of the water. And from my limited understanding, it's the micro organisms rather than the plants that do the cleaning up.
Here's an alternative idea you might be able to do.

My bath water goes into a 'wicking' garden bed - This might be a good idea if you're worried about disease - everything gets watered from below, and filtered through the soil and soil organisms. These can be pretty easy to organise - a plastic liner, a thick layer of woodchips, then compost on top, plant into the compost.
The original designer kept it nice and simple, and it's been way overcomplicated by others since then.

He even builds wicking beds into swales - good descriptions and pics and a lot of background info as well, here <http://www.wickingbed.com/>

Basically, build a nice long swale on a slight slope, line with plastic sheet, nice thick layer of woodchips as a wicking medium on top of the plastic, then topsoil, or compost as a growing medium on top. Water in the top end of the swale, trickles along the plastic sheet and through the chips, where lots of fungi and microbes get to work, and the water wicks up into the garden bed above. Don't worry about the soil falling into the woodchips - you replace the system every few years and get great compost from the wood chips, apparently. I'll let you know in a couple of years if it works!
T

[steev]

That's a very interesting site. I can certainly see wicking beds being very useful on my farm. Since I currently plant in lanes between my trees, I think I could run such a bed down one side, eventually switching to the other side. The dewcatching rocks are very clever. I think this could have great mushroom-production potential.

[raymondo]

The thought of redoing a large wicking bed every few years puts me right off. Is there space to pass the water through a small wetland then into a swale? If not, I'd go with a swale and plant it out with bog plants. This may go some way towards neutralising the alkalis from the soaps.

[richardw]

For getting the maximum benefit form the reusing of the grey water for vegetable garden a system a friend has would be one of the best uses ive seen,his is piped around a block of Eucalypts trees,and boy they certainly grow amazingly fast because of it,his is for fire wood only but for the garden this system could be used to grow carbon for the compost heap by growing fast to break down trees like Radiata pines,willow etc,once the logs are rotten enough they then can be added to the compost piles

[templeton]

MD, I've been giving this a bit more thought.
there are too many variables to give absolute advice.
approaches will depend a lot on your comfort with using grey water on food crops, the level of 'greyness' in the water, daily water use, need for water in the garden, scale of site, slope, time resources, access to appropriate plant material, climate etc.
First, let me say I would just go with the simplest possible approach to start off with, then modify as I went. an earthen swale that you can fit a mower into, chuck some grass seed in or just let it go weedy with whatever gets comfortable growing there. Monitor the throughput and the growth in the swale.

You want it to drain enough that it doesn't go stinky and anerobic, but have sufficient lag time in the system for the microbes to do their work, but not so much that it uses all the water up.

eg dry climate, low water input, heavily veged swale might mean no water out the other end.
wet climate, high water input, shallow slope might mean anerobic swale. steep slope might mean too much flow through.
I think it's probably too easy to overthink it - just go for it, and be prepared to modify it along the way. You can always line it, or dig a pond in the middle, or add reed beds etc.
good luck.
T

[steev]

Nothing ventured; nothing gained. Start small with low investment of time, effort, and cost. Only those who can change course should try new things.

[12540dumont]

We've been using our grey water for years.

Note: Kitchen sink water is NOT grey water. It's black. Don't use this in the garden and you have no worries. There's too much grease, etc. in this water. We put this water directly into a flower bed. We use a bucket of charcoal with holes in the bottom of the bucket. Most of the really yucky stuff gets trapped in the bucket, which I toss out into one of the far terra preta fields every so often. (The charcoal helps keep the smell down).

Our shower/tub water runs directly to trees. You can connect the outflow pipe directly to a hose, just don't reduce it too much. Go with the biggest hose coupling that you can get. You can then move the hose to a different set of trees every few days. In the winter I just move this to the rose beds until they are completely boggy and then shift it around to anyplace that isn't already underwater

Our neighbor set up a vege washing station out doors with a similar set up. The outflow connects to a very large hose that connects back again to a garden hose.

Swales work wonderfully for cleaning water. Cat tails can even remove heavy metals from water. greywateraction.org/greywater-recycling Here's a link.

[steev]

Don't think I'd want my cattails sucking up heavy metals, since I'd like the pollen for adding to batters, the young cobs for cooking and buttering like sweet corn, and the starchy roots for winter fare.

[mountaindweller]

Good advice! At the moment our "system" is simply an outlet and a puddle. We're not fuzzy about bugs, they make us strong. More the soap which changes the ph. And we cannot use bath salt either because too much epsom salt is bad for the plants. I often clean with bicarb and vinegar, what does this do to the soil?
Why should be kitchen water black water? The bad thing is the grease and I still don't have an idea how to get this out. There is some salt too and dishwashing liquid. The kitchen has no outlet yet anyway.
Digging the swale will be major and I am not looking forward to it.
For the hot water of the washing machine I thought of a container were the outlet is smaller than the inlet, that the water flows out slowly and cools a bit meanwhile. In Brisbane I collected it in a garbage can and if I forgot to use it immediately it gets really smelly.
I have to add: we have a very low tech system that funnels rain water from the street into our garden. It does not work for drizzles but in our recent downpour we had to close the system it was far too much water.
There are open channels and a pond which is halfway finnished.
I really disagree with the trees. Sure they use water, but were trees are there traps the moisture. The soil in a forest is alway wetter than that of an adjactend field. Trees make water - that is not very scientific. And if I would plant evergreen trees there I would have a windbreak foe the veggie garden as well.

[galina]

There seem to be two different ideas - the use of all grey water (except toilets) vs the occasional use of 'lightly grey' water.

We are in the latter category and I put the plug into the bathtub and collect shower water, which I gravity pump into a large container, then water onto established plants (or rather onto the soil between established plants). I have done this for years, when my stored rain water runs out and it seems to be fine. Similarly all my vegetable washing is done in a bowl that can be taken out to the garden in drought times. But the emphasis is on lightly grey water. We were told by our organic growing association that kitchen sink or washing machine water (apart from the final rinsing water if hand washing clothes) were way too dirty or soapy for use on vegetable plants.

In the UK there are reed bed water filtration systems that cope with cleaning up all types of grey water. A good idea, except most gardeners have not got the spare acreage to establish such a system.

www.gardenorganic.org.uk/news/news_topic.php?id=390

[olddog]

i have been trying to figure out a graywater system, but it seems so complicated, to get it right, long term.

I did hear of someone that uses algae, instead of cattails, etc., which sounds like it would use much less space in the yard. Haven't heard the specifics, though. You might have to use a bubbler or some oxygenator, I would think. Or gravity (the graywater could drop from a height down to the pond).

Has anyone tried this?

Another way someone else tried a graywater system, was to run the graywater through a bed of compost, no chips, no plants, which sounds kind of neat. Not sure how long that would last before you had to replenish the compost.

Right now, we just run the shower water onto the berry bushes; they have done well.