What sewage system for me?

Rory has contacted me asking what sewage system he should buy.  Here’s Rory’s question:


“Hello Michael,

I recently bought your book (which is brilliant) as I am in the process of planning a new house to be built on Bruny Island in Tassie, and I knew that I would learn a lot from your practical experiences in dealing with collecting water and dealing with waste onsite. I have long been a regular visitor to your website and blog, too.
I have an acre of land so I don’t have the same incredible space constraints as you, which I’m glad about!  I certainly admire your principles and your perseverance (in Sydney!!!!), the sustainable house continues to be just an amazing undertaking! I’m doing all this by necessity, not by choice.
Anyway, I thought it would be in the book but I was hoping you could tell me the brand of the agricultural filters and air blowers that you are using in your wastewater system? I may decide/be forced to buy a commercial system one day, but I want to consider what’s involved in doing something myself first (or with a consultant). I like the idea of it being modular and user serviceable and capable of being easily “re-started”, if it all goes horribly wrong.
Also, I was interested in whether you’d use a similar AWTS if you lived in a rural context that treated everything, or whether you’d be tempted to employ a simple dry batch composting toilet to deal with humanure and have a AWTS that deals only with grey water? My wife would love a flushing loo, but I like the principles of source separation.
Before I go, congratulations on all you’ve achieved. i think you are doing a great deal to bring about the changesthat are needed for our human world to have a future.”
And Rory said,
“I’m happy to be part of the growing conversation about ethical living.
I think dealing with the technical issues of recycling water and better utilising the end products of modern living are some the biggest  issues we have. And like you, I am interested in promoting solutions for recycling that work, that are rooted in both science, pragmatism and experience, and not the schizophrenia that seems to pervade most peoples attitude to dealing with our poo (including most regulatory bodies).
All the best,
Rory, Switzerland”
Before I answer this question here I wonder if anyone else has a related question about choosing a system?
I’d like to provide a detailed answer here as this is a question I receive almost every week.  I’ll leave the answer for a few days so anyone may contact me about this topic with their issue then I’ll put the answer up here.
Be well, and love your water, love our planet,
7 Responses to “What sewage system for me?”
  1. Mary-Jane says:

    I am in a similar position to others, we are building on a rural block and I am looking for an effective & sustainable on site sewerage treatment. We will be having a flushing toilet, mainly for resale purposes, although we have no plans of selling. We have a small composting toilet in a shed on the property and it has been great, no smells or issues, although it only gets intermittent use.
    I would like to treat water to a level where I could recycle to the loo & washing. We are restricted to where we can drain treated water because we are close to a dam and two gullies that lead to a creek. The systems with membrane filters seem expensive and I read somewhere that Michael had used a sand filter instead. If we wanted to use a sand filter would we have to build the system ourselves? and is it cheaper? Or can you recommend some reasonable priced alternatives


  2. Phil says:

    Yes i too have been researching for a waste system for my bush retreat. Most people are addicted to flushing but dry composting appears better accept having to explain to guest how to use the compost loo.

  3. Rory says:

    Hi Tracy,

    Not sure if you’re interested but there’s a system I’ve found called Aquatron that combines a flushing toilet with a composting loo. It works by using a fairly basic looking centrifugal separator to separate solids and water. As its reasonably low-tech it looks really quite promising, but I haven’t looked into it seriously in terms of owner feedback, track record, importing into Oz, etc (think they are a Swedish company). So, this is definitely not a recommendation, I’m just forwarding on something I’ve come across FWIW. In case anyone wants to take a look, the website is http://www.aquatron.se/index-2.php.



  4. Lizandhercat says:

    Would be very grateful for info re pros and cons of various systems as we are in the process of purchasing an old cottage in Canberra with the plan to retrofit, extend and create a low energy house and sustainable food production garden. One toilet or 2? Clivus? Ecolet? Worm based system? Other options?
    Read about Biolytix last night and it sounded perfect, then more searching revealed the company imploded and many people had expensive problems. So info re potential pitfalls of various systems also welcome.


  5. Tracy says:

    Hi All. We are in a similar situation. We have a small farm a weekender, in the Lower Hunter. We have about 8 acres of cleared flat land and 32 acres of beautiful forest. The cleared land is predominantly sandy (and I mean Predominantly! It can look like sand dunes after a flood!). I am desperate to find ways to improve the soil and using properly treated human waste seems like a great option. We currently have a pit toilet and a composting toilet. The composting toilet works really well and is currently inside the house. When we rebuild (with hempcrete wow) I want to put the compost toilet outside (weekend renters struggle with compost toilets) and put a flushing toilet inside (not my choice but it feel it is necessary). So I want to make the most of this waste.

    The pit toilet is kind of useless because it all drops into a big hole and doesn’t seem to filter into the surrounding earth to provide any benefit. I look down into the pit toilet sometimes and think “what a waste!”.

  6. cilantron says:

    I’m looking forward to your response to Rory’s query as mine is very similar to his.
    I’m wondering if the water, once it is treated, causes any problems after long term use on plants or trees?
    a friend had a worm waste water unit and sporadically had problems with the worms drowning and dying. Once she realized it wasn’t working, she them had to have it pumped out, buy new worms and start again. Is this a problem with current worm systems? What are the options in Australia for commercial worm waste management?


  7. Andrew says:

    How do worm systems deal with variation in demand? We are barely at home during the week but on the weekend washing machines, loos, showers, etc all get used.

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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.