Vanuatu 2016, Joe’s Place. Designing a composting toilet system

Project Composting Toilet Vanuatu!

The opportunity to build something quite unique! This was my first design from researching many others.

So why a composting toilet?

There are many reasons! You may have heard the name before because they are growing in demand, also in technology. $6000 can be spent on electric ones these days which shows it's a modern technology and not just a lower classed product. When you take a look at what our current toilets do you realise they are much more wasteful than you first thought. With a conventional flushing loo we are weeing and pooing in clean drinking water and then using 5 litres of clean drinking water to flush it away! We used to use our waste as fertiliser back in the day...it was actually worth money! Yet now when we need fertiliser we buy it. I mean check out this ladies garden in the dessert fed by a composting toilet system...

Sewage should be composted...nothing else, it's that simple

So there we have the issue of waste of water and waste of nutrients into the soil...then we look at pollution ..

As with Earthship passive solar design for the majority world and the western world there are also 2 types of composting toilets. There is the more elaborate and expensive system like in a Global. Or there is the simple version, I took ideas from the simple version this time round and changed it up a bit.

We had a budget, a very low $50 one. We wanted to address the issues that the locals knew they had... mainly the lack of water up in their mountain village. When getting involved with design you have to look into what the people living in the area are doing and not change it too much to the point where they won't use it.

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Currently the locals in the village are using long-drops. The smell quite bad and even though the locals have used them for many decades they never really become immune to the smell. As soon as a hole gets full it's filled in and the toilet block they were using is then moved to another location.

Down on lower ground the locals obviously wanting to update have installed flushing toilets but with a whopping 5 litres per flush of clean water this puts a strain on resources in dry season. There isn't even this option in Joe's village, Just to give you an idea ..Pictured below is Asel and Little Bonnie. They're headed up the mountain to visit her family, each time they go they bring water up. There is no water up there at all - no river, nothing. Locals have to head down to wash their clothes or pick up drinking water. As community spirited as this is flushing toilets aren't the best idea..not yet.

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So we explained the composting toilet along with it's pros and cons, then I designed one which could tackle all the desires and yet keep the build cost lower than $50.

Here is a link to the rough plans...

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I noticed when researching many designs didn't separate the solid waste and urine in the same unit or if the did the urine went into a chamber be be dealt with later. I wanted the urine to be simply gravity fed straight to citrus trees as they love the nitrate. The chamber of the solid waste is dealt with around the back of the toilet, this ensures it is also vented away from the user inside. The urine pipe wraps around the bucket so as not to get dirty and stays un-kinked.

Here it is in production surrounded by housing. There will also be a stool stool (double worded on purpose) as a the gravity fed composting toilet had to be built quite high. This also makes for a much better sitting position for the colon.

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So here you can see how it is all pieced together. The urine funnel is attached securely to the top. Urine passes through this and out via a long tube which wraps around the side of the bucket to stay clean.

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Below you can see how the 2 compartments for separating the fluids and the solids sits. This is essential for preventing smell and since urine and poo are both are very different products it's good the deal with them separately. Solids head straight into the bucket and is then covered over with sawdust or ash. ...or both. It won't smell at all...I have seen and given the sniff test first hand. (you can't smell anything...honestly).

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Urine is great for citrus trees such as lemon ...because it has nitrogen in it. It's quite simple to treat so it literally gets piped by gravity from the funnel in the toilet out to a trench and to the trees. This has to be done in a way which the land can deal with (not to much wee in a small space of soil)

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The trench is dug and then filled with old bits of concrete (as it's difficult to find rocks). Then filled over with dirt once the hose is in.

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As for the aesthetic design...just how they like it. We left it to the very talented workers to get straight into it to make it their own...an awesome job!

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They used local materials, coconut tree leaves mainly for the roof and...

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Bamboo for the cladding.

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And voila... almost done.

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As you''ll see below they left a space in the back to be able to empty the bucket out once full, this is also a good way to vent the toilet.

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More updates soon as the project gets further along 🙂

 

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