View Full Version : Grey water swale system?
22-03-2012, 11:59 PM
Has anyone tried diverting their grey water into swales? I live in a fairly arid climate in which rainfall alone wont support fruit trees... well usually. I have a goal to aquire 2 or 3 acres with a gentle slope facing north to north east. Zone 1 would be at the top of the rise. I've looked into the idea of creating depressions around growing areas to make the most out of infrequent, heavy rain events which seems pretty rational but I've always liked the idea of the frequently producing swale too. Just doesn't seem effective in a climate that is dry for most of the year though. Diverting greywater might be the way to do it. Obviously it would have to be staged so as to distribute the water fairly evenly but there are other concern such as water temperature (from showers and baths) as well as long term nutrient load and chemical balance issues from soaps and so on.
Does this idea sound plausible to anyone and what are people's experience with the couple of potential issues pointed out?
23-03-2012, 01:00 AM
I have seen it at the Permaculture community called, "Mountain Homestead" here in Coquille, OR... ..I am not affiliated with them, nice people though. Anywho, The kitchen building was located highest on the slope & its grey water emptied directly into the veg bed swales, diversion ditches, etc of their kitchen garden system, in a clearing, in a forest. Last time I visited, as the dishes were being done I watched the water empty literally into a ditch next to a large planting bed filled with leeks, blue columbine, and other plants & veg. The ditch does act like a swale I am sure in the rainy months since we are in a temperate rainforest here.
I am planning to do similar, but I will have a shock tank due to concerns about heated water scalding roots.
Have you ever heard of the Grey Water Guerrillas?
Be aware that any kind of tank which holds the water for any period of time can turn to black water. I had a surge tank for my greywater and it turned to blackwater, now my greywater empties directly into an infiltration basin with no tank. I don't use hot water in this system, so no cooling is necessary.
Good reference for everything greywater: http://oasisdesign.net/greywater/index.htm
23-03-2012, 04:35 PM
Front page of PRI has an article about greywater (http://permaculture.org.au/2012/03/22/constructed-wetlands-treat-waste-water-with-weeds/). First comment from Řyvind is a youtube video (http://www.youtube.com/watch?feature=player_embedded&v=PBMpaWq4EKE) about an American greywater system installed on a small urban lot.
I'll do a quick breakdown from what I watched. And as long as you have some gravity on your side, it should be simple to do it the same way. Greywater feeds from house via a 3-way tap (ability to send it back to incumbent sewer connection) into a recycled plastic tub filled with wood mulch (underground). This tub is like a shopping cart, holes all through it so the water enters directly into a pond-lined gravel bed (through the mulch as a pre-filter) with the pond 'falling' through gravel and roots of plants to a perforated pipe at the end. This perforated pipe picks up the water and takes it to a multiple hose/tap manifold which then directs it around the property to mulch pits. Water is never exposed to the air, or contact of people as it's under the gravel as it's being filtered.
If you had your perforated pipe emptying into your swale, your water would be 'almost' clean and as long as kids weren't eating the dirt and root vegetables weren't in direct contact with the water, I fail to see a problem with it.
24-03-2012, 12:32 PM
If you can get your hands on a copy of the Designer's manual take a look at the water chapter. I was reading it last night. Heaps of great ideas about how to do this. We talked at the PDC last week about how to make a worm powered grease trap as the first part of the process - I haven't watched the video yet but that could be what the plastic tub is doing. Grey water is best used for tree or mulch crops, unless you have a really good treatment system in place.
Off to watch that video now...
29-04-2012, 01:55 PM
root vegetables weren't in direct contact with the water, I fail to see a problem with it.
If the water is filtered through the gravel and microrganisms would clean it further why the need to keep root veggies away from it. Surely the other plants are taking in the same water and still be ediable. It is a bit like dog poo in a worm farm and you use the leachete from it, I dont believe it has ever been proved beyond doubt that the plants can pick up pathogens that can make you sick. I could be wrong. Hmmm me wrong?? Never thought of that lol
29-04-2012, 06:50 PM
You're never wrong, Brian. I was erring on the side of caution, rather than give out information that 'could' be potentially dangerous. Nearby irrigation, rather than direct to a tuber or root, would add another layer of solid filtration as the water wicks through capillary action.
I also installed commercial greywater systems that were less biologically-complex than the system I described (yet met the minimum requirements set forth by the relevant authorities), even getting old greywater (nearly black) directly into my mouth in a freak accident and I'm still fine......ish.
I recently watched 'Urban Permaculture', the latest Ecofilms/Geoff Lawton release and the systems I installed feature at one of the properties.
29-04-2012, 07:14 PM
I had a grey water system at home on a gravity feed to the front lawn during the Qld drought years. I later added a pump so I could pump to the back yard. It kept everything alive and green but rainwater made it grow when it did rain. We have had over 1m of rain here this year so I dismantled the system. My yard is soggy enough.
29-04-2012, 07:30 PM
What comes after a flood? Keep it handy, I'd say.
30-04-2012, 01:31 AM
I run my greywater to a short swale at the uphill side of the orchard ... thought is that the greywater plume migrates down the gradual hill beneath the orchard feeding the deep roots. This, in conjunction with the deep mulch has significantly reduced any additional watering necessary (except towards the end of summer when the fruit is set, after no rain for months). Plus the mulch has created such great soil around the trees after the past few years!
11-05-2012, 10:41 AM
Assuming you are being super careful not to put anything that's not biodegradable down your sink, like detergent, fluoride from toothpaste, hair products and alkaline soaps, you might....might want to collect the gray water behind a swale, but you are corralling it into a zone where it needs lots of compost to break down any questionable ingredients. If you are collecting rain water off the roof and you have asphalt shingles or any kind of roofing material that isn't wood (even red cedar has growth inhibitors) you won't want that water going straight into unamended soil.
Because using gray water is illegal, and it shouldn't touch the ground, I thought I would take that into consideration in dealing with gray water. I am not a saint and there is the occasional thing that shouldn't go down the sink, I have built a large, wide composting area in a kiddie swimming pool, and the gray water empties into that. But it is always...always full of mowed weeds, manure I haul from a neighbor, and quickly compostable stuff, the gray water is quickly absorbed and worked on, being overwhelmed by good composting bacteria. It's damp, but not sitting in a swamp. Depending on the water level I may cover it over, but sometimes the sun helps me out by evaporating any extra. This is not a quick pile and I don't have a family of four, so it's not a lot of water. I have several house and deck plants that some grey water goes into, and what's left over goes down to the kiddie pool. I do dishes in plastic dishpans that line the kitchen sink so I have an option of where to put the rinse water. But the wash water goes down the sink.
If you really want it to go to a swale, giving that swale a good amount of composting materials would help everything be healthier :)
11-05-2012, 01:30 PM
Or put a reed bed between the water source and the swale to clean it up. Though I quite like the compost in a kiddie pond idea!
11-05-2012, 05:38 PM
does anyone use the warm water as a resource?
11-05-2012, 08:35 PM
No - but there's a really good thought just on the edges of consciousness waiting to crystallise now that you say that.....
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