Sustainable Greywater

4 03 2015

One of the best aspects about Mon Abri that I have never written about here on DTM is our greywater system…. and the only reason I have so far omitted to do so is because I mysteriously ‘mislaid’ the photos I took of the system way back in maybe 2003 shortly after the slab was poured.  I’m not one to lose computer data, I usually have multiple copies of everything I’ve ever written or photographed or downloaded on various CDs and DVDs and now memory sticks, it’s just that sometimes I don’t know what I’ve done with them!  Last year, I did a talk about this amazing greywater system for Noosa Permaculture, and had to rely on some less than perfect pictures off the internet.  Well dear reader, one good thing about cleaning up in readiness for a big move is that you find things you haven’t seen in years, and what a trip down memory lane some of those finds can be…..

Greywater is what goes down your drains, usually to sewerage.  For 99% of people, pull the plug, and you never ever have to worry about where all that stuff goes, but when you live somewhere not connected to any sewers like us, then you have to deal with the waste that goes down your kitchen sink, hand basins, shower, bath, and laundry.

Unless you pour paint down your drains, or vast amounts of chemicals like bleach or other nasties (definitely NOT recommended in ANY case…), greywater is not toxic.  Councils treat it like it is, yet when you think about it, what’s in greywater?  Apart from soap and washing detergents (which are by now largely bio-degradable), you’ll get hair, skin particles, lint, body fluids and… well lots of water.  The kitchen sink is a different issue because food scraps and fat from pots and pans also go down the gurgler.

Now to my way of thinking, and the thinking of the inventor of this system, none of those things are particularly ‘nasty’.  “Out there” in the environment, wild animals die, poop, piss, and yet you never smell them.  Mother nature has a way of treating this ‘waste’ by returning it to the soil as a resource, and there’s no reason why we should not be treating our own wastes in the same way.  But humans believe we are too clever to mimic nature, and we like to involve technology to do our bidding, often when it’s not even required, and so it is with sewerage; which after all, is 19th Century technology.

Now normally, when you live in the country like us, councils will make you install expensive treatment plants with pumps and storage tanks and complicated plumbing like the Biolytix I mentioned in another post, or devices with names like enviroflo, or ecoflo, or ecosafe or any other number of ‘green’ marketing names.  Some deal with your toilet waste as well, some don’t.  As a firm believer of not mixing water with toilets and thus making ‘black water’, I would never consider any system that mixes the two.

Most commercial greywater systems involve storing your waste water until the tank is full whereupon an automatic valve will allow the stuff to be pumped, usually to a sprinkler system, well away from your house and gardens of course, because councils consider greywater unsafe.  Which it highly likely does become, IF you store it like that!  Germs love water to breed in.  The longer you store greywater, the more bugs it will have when you spray it all over the lawn (which you then have to mow).  I’ve seen such systems all around us break down (pumps don’t last forever) and as a result they have to be inspected yearly, or even twice yearly depending on what they are.  Filters have to be serviced, float valves checked, plumbing unclogged, and frankly paying someone hundreds of dollars a year for the pleasure of owning an unsustainable system really gets up my nose….

Enter Jonathon Berry’s Ecodesign greywater system…….

Trenches from the house with greywater pipes laid

Trenches from the house with greywater pipes laid

No pumps, no filters, no inspections (you can’t do yourself), zero electricity use, and less than half the price to buy.  Ours was the first to go in within the Noosa Council jurisdiction, and they had never seen one before; as a result, they gave us a hard time approving it, but there was no way I was installing anything else…..  after paying two geotechnicians to prove this would easily work in Cooran, the Council relented and allowed us to put it in as a ‘pilot scheme’.  There are many others around here now, thanks to us paving the way to sanity.

This system is simple beyond all expectations.  All the waste water is gravity fed to a disposal area via a series of distribution pots, which are basically irrigation valve housings drilled with 13mm holes to allow the water to go to the soil, all below ground.  Instead of growing lawn around this area, you grow trees (bananas in our case, and loads of Arrowroot and Pigeon Peas and Crotalareas for mulch use elsewhere).  The pots mentioned above are like upside down buckets, the bottom of which (now at the top) is removable

Distribution area showing how the pipes split the flow to a total of eight pots

Distribution area showing how the pipes split the flow to a total of eight pots three metres apart

so that you can see what’s happening in there.  Once a year, you are supposed to inspect them all and remove any hair or lint that may supposedly fill the thing up and make it inoperable, but in practice, there’s nothing to see.  Worms in the soil simply dispose of it all organically.  I recently had another look after a six year absence (I’m slack like that!) and found very little to do apart from removing some dirt that ants, I presume, had placed there.  It’s my kind of system, almost maintenance free!

Water filling pot

Water filling pot

The kitchen side of this system is in some ways even more brilliant…..  anyone who’s ever had to deal with a grease trap will know what I mean when I say it has to be the most disgusting job on the planet.  Grease traps alone are one reason why owning any other system is as dumb as dumb can be….  especially when you know common composting worms will not only make the grease disappear, but also turn it into worm castings for your garden…

What Jonathon came up with here is basically a worm farm to replace the grease trap.  He calls it an Aerobic Grease Filter, because the trick here is to not have everything smothered in water and becoming anaerobic and smelly and toxic….  just like nature does all the time!  The water flow from your kitchen sink is divided into four equal outlets over a 1200mm plastic trough originally designed for livestock to drink from.  A 100mm waste attached to two more pots downhill take the waste water to the soil.  This water is first intercepted by another pot placed over the outlet as a filter of sorts.  100mm of gravel is then placed at the bottom of the trough, and covered with compost.  Add a handful of composting worms or two, and then mulch.

Aerobic Greas Filter before filling with compost worms and mulch

Aerobic Greas Filter before filling with compost worms and mulch

As your dirty kitchen water hits the mulch, the food scraps and fat are filtered, and the worms come up to consume it all.  The water continues down through the gravel, down the outlet, and out the two aforementioned pots.  This never smells, is a constant source of vermicastings for your garden, and is easily the most sustainable way of dealing with your kitchen waste water……

Ours is under our deck (this shot was taken before the deck was built) and believe me, if it ever smelled, we’d know about it!

Once it’s filled and operational, it’s virtually maiGreywater Aerobic Grease Filtersntenance free, and I only dig it up if I want to fertilise a new garden bed.  The stuff that comes out of this has to be seen to be believed, and why anyone persists with the alternatives selling for thousands of dollars more and costing hundreds of dollars a year in maintenance is all beyond me.  I’ve included a pic of a finished unit from somewhere else, ours is awkward to get a good shot of now it has a deck over it.

On the day of our first ‘pilot scheme’ inspection, the head honcho from Noosa Council plumbing section personally did the deed.  Jonathon was there to make sure his system made a good impression, and he helped me ‘service’ the aerobic grease filter.  The look on the inspector’s face as he watched the pair of us elbow deep in the worm farm, fishing out thousands of odourless worms for the garden was priceless…..!  The inspectors never returned, we had proven our point.





7 responses

4 03 2015
Anthony William O'brien

I do understand council regulations on this topic. If I had designed and installed the system it would probably be quite nasty. However, councils do have to start thinking differently. A well designed and installed system is a bloody good idea, but maybe not on a 200sq m block.

4 03 2015

You live on a 200 m2 block? Do you know how small that is? My veggie garden is 200m2….. most houses these days are bigger than that…..

Besides, IF you simply live off the water that falls on your roof like we do, then all you are doing is returning that water top the ground without adding one single drop…..

4 03 2015
Dr. C. Scott Taylor, PhD

Aha, good to see the inner working of that. Thanks for the detailed description.
I can attest, having hung my head over this, it has no smell.

4 03 2015
Mon Abri – For Sale! | Damn the Matrix

[…] The house is plumbed to what must be the most ecologically sustainable drainage system, described in detail at this page on this blog. […]

4 03 2015
Anthony William O'brien

Mine is 700 sq m, but some of the new blocks are that small

5 03 2015

Good article. I’ve seen other articles regarding grey water that say similar things (keep it simple, avoid storage, avoid pumps). Looks like a great system, and exactly the sort of thing I have in mind for my place (where I’m trying to work out how to retrofit such a system — at the moment just hand-bucketing from the laundry and kitchen).

Do you use a composting loo as well?

Cheers, angus

5 03 2015

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