What’s a good sewage system?

A beaut question lobbed into my inbox this week and here it is:

‘Hi Michael,

First up let me tell you how much I have enjoyed your book.  It is a permanent coffee table fixture in our home at present as we are planning a new house and endeavouring to implement many of the same principles you have adopted.  Infact it has been so popular on the coffee table that three guests have asked to borrow it and all now have their own copies.
We are currently building a home in the Ferguson Valley, Western Australia and have run into some difficulties finding a suitable waste water treatment plant that complies with the WA Health Department’s requirements and does not have quarterly costs for inspection and chlorination.  the site we are building on is loam over clay, and the first quote we got for a conventional septic system was $12,000 (which startled me for what is essentially just a few large concrete rings and a leach drain)
One of our friends installed the last new Biolytix system in WA and  was told by the disgruntled contractor that the “secret” to avoiding the costly annual repairs was to run the laundry water through a conventional greywater diversion system as apparently the it is the fibres from nylon clothes in particular which clock the system up.  Obviously as they have closed down again this is not an option for us.
I was wondering if you could suggest any commercially approved alternatives that would work along the similar lines to your system and have been approved by WA’s Health Department?
Regards,Anthony Congdon’


May I suggest two systems:

I use a system similar in design to the Aqua Nova.  I built tanks to fit my small back yard – 5 m wide, ten m deep with most space already taken up by the 10,000 l rain tank.

My book, Sustainable House 2 Ed, has details in the sewage chapter.

Basically, it’s: a settling tank; when that fills a pump transfers the primary liquid to three tanks where air is bubbled through the water 24/7 to clean the water; when the toilet or clothes washing machine goes the water is drawn from the final aerated chamber through two sand filters then past an ultra violet lamp for disinfection and voila – sterile water.  Maintenance is limited to replacing the UV lamp every two years and I do that.  About once a year I pump out sludge to fertilize my garden.  My water tests at zero faecal coliform every time and very little energy is used by the 60 watt air pump and the 20 watt UV lamp.

As for the red tape; both are approved by health agencies and you can get the suppliers to train you to maintain it.  You can even get a phone line hooked with a back to base alarm so that if there’s a problem the supplier will either come out or talk you through it and that’s enough to achieve the same health outcomes that  the high cost service arrangements seek.

Let me know if this works and any problems you have.

May the recycled water be with you all,



One Response to “What’s a good sewage system?”
  1. Thanks Michael, great idea about the alarm.

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  • Michael Mobbs

    Michael is a former Environmental Lawyer who is uniquely placed to consult in four main areas:

    • Sustainability Coach and Speaker,
    • Sustainable Urban Farm Design greening, watering and cooling the cityscape, roads, parks, suburbs,
    • Major Projects Consultant Commercial and Industrial,
    • Residential Sustainability Consultant.
    For permission to re-print any articles or to book Michael for a speaking engagement go to Contacts. Please ensure all quotes from Michael's blog include a reference to sustainablehouse.com....au.