Eco-building Biomiler / Eco Shower

There are lots of posts that I haven't written yet, so in order to let you catch up with the projects that are going on here, I will give you a compacted post about our biggest project, in the last few months.

Me - Lucas - Rafa, my mom Ires, her boyfriend Rolf, Alika - our hard working volunteer that is with us since December - Pácio and Laura - volunteers during November - and Dennis, a good friend of mine, were the brave people involved in this awesome project! 

This project started last year, around Spring, when I learned that it's possible to heat up water with compost (or with almost any organic material composted in the right way).
I had to try it myself!

So, during Summer, after cutting down the excessive grass on a fruit tree terrace (the grass was already dried in June) we made a big pile with the purpose of decomposing that grass in a quite fast way, by turning it every 2 days and watering it. The reason was that we were in urgent need of good soil.

The pile got so hot - 68º C // 154.4º F - and I was not using this heat, what was really bothering me. So I thought about trying this project, especially because we have been receiving volunteers and this kind of Sustainable structures and ecosystems are always interesting to show and share. Nonetheless we would save a lot on water and natural gas! 

Then we bought a 1000 L used plastic water tank and Rolf took more then 3 hours to clean it with a high pressure water cleaner, once it had been used to industrial proposes. 
After we started assembly our pipe system, we made a spiral, with the pipe, on the compost pile and after 8 to 12 rounds coiling this, we add another layer of compost on top and continue this sequence until we fit all the pipe in there. On the first try we used:

• 100 meters of plastic agriculture pipe 16 millimeters thick (Cost about 15€ per 100 meters.)
• Some drip irrigation connection pieces and taps, fairly cheap too
• Old Shower head, from a solar shower
• Bamboo that I had harvested the last year
• The 1000L water Tank

1. We positioned the tank on a higher terrace so that the gravity will provide water until the tank runs empty; 
2. We also covered the tank with cardboard - 2 layers - and then 2 black plastic sheets (the plastic will protect the cardboard from rotting, doesn't have to be black but normally is easier). After covering the tank so that no light gets in it, we could be sure that no algae would form (if light gets to shine on the water tank the algae will form and eventually close the shower head).
3. Even with no algae and using clear water from a water spring we add a easy to clean water filter, just in case.
4. In order to fill the water tank we connect a pump and then fill the necessary water.

We got hot water in less then 72 hours. The compost had reached more then 50ºC and the water would came out already at around 40º C. The water temperature varied from 38-48ºC, once this shower was used 4-6 times a day (volunteers, guests, etc... ). 
After 4 weeks the temperature drooped and after 6 weeks there was no heat left to extract (at least not for our purposes).



This is how the pile looks after 6 weeks of use. We could already use this compost in the garden as a mulch layer; the organic material decomposed faster and it was ready to be absorbed by the plants.

After the success of this little pile we were prepared to try something a bit bigger, with a longer lifetime, so we didn't had to make a new pile every 4 weeks.

I researched - thank God there is the Internet nowadays - and I found interesting posts about "Biomiler". With this resource is possible to heat houses or greenhouses, using plastic pipes to heat water or bigger plastic pipes to heat air.

My mind was blown away when I read that a big Biomiler can run for 18 months and still produce warm water.  I had to try this out!

That leads me to the next chapter.
These Biomilers were using green shredded wood (but can also be dried wood!) and that was a problem - I didn't had anybody near me that had a shredder to make this wood chips. So I spoke to my mom and Rolf and together we bought a wood shredder.

And so the little ants begin their work - I say this because you have no idea the amount of wood cuttings we needed for this project!

As you can see, branches go in and chipped wood comes out - easy! 
Now I will show you the structure I made to pile up this big amount of shredded olive branches.
And why did I used olive branches? 
In Portugal, Autum is time to harvest the olives to make olive oil. Along with this process the olive tree are pruned and, traditionally, people would burn the branches. Composting it isn't an option for most people here at the village!
Since the risk of fire is quite high in Portugal, we believe that using this resource to improve the soil in our land, can encourage the local people to do the same... one day!



I went to a local store and I was able to get some broken pallets for free, So I nailed 8 pallets together. After finishing this "frame" I was worried that the Biomiler needed isolation.
That wasn't the case, but it can't hurt to make a dried straw bed under the main ingredient (shredded stuff ).

 

In this picture, Pácio was filling up straw and making it equally spread.



Then we added a plastic tarp so the straw wouldn't get wet right away. We made a few holes on the lowest points to let the excessive water run out.






The shredded leaves and little brunches needed to be really wet - it's possible to use a garden hose or a sprinkler to equally make everything soaking wet.

We made a layer of ~30 cm on the bottom, with shredded branches, that we compacted a little - every 10 cm I walked on it, with running water on, to compact the layers.

The following pictures represent me on top of a 30 cm layer of shredded wood, that I have watered so the color was darker compared to the other pictures.

 

You can see the pipe is quite thin and it's easy to twist it. This part requires a lot of patient and concentration - if the pipe gets twisted it will be a weaker spot in the future.

For this project we used 170m of plastic water pipe (diameter 16mm), but you can use any pipe for your project. 

The 170 meters of pipe were rolled out in 3 layers, each layer of pipe was separated by 20 cm of shredded wood. 

The first water pipe spiral should be ~30cm above ground, in a bed of shredded wood, then when a good amount of pipe lies down you simple add enough wood chips to make a new layer of 20 cm.
The second layer should be at ~50cm above ground, third layer at ~70cm, etc. Then it should be added at least 30 cm. 

We started at 24-11-2016 and only finished completely at 02-12-2016 - but we didn't work in this project everyday!

On the 28-11-2016, Dennis tried the shower to tell us if it was hot enough...

...The water wasn't hot but it showed 37ºC already.

It took us longer to finish because we underestimated the amount of branches we needed. 
Before I told you that we used mainly olive branches- I think about 85%. The rest was from other trimmings that we had to add to get enough biomass. 
We have many old olive trees that have lots of branches, so every 2 years, the olive trees get harvested and many branches are cut out. We used branches from 34 olive trees.

Olive, ceder, apple, pine and apricot wood were the remaining ingredient. If you shredder yourself or if you buy wood, it is important to make sure you don't use more then 15% of pine wood, once the resin in the pine wood is too strong for the microorganisms to live.

Temperature from the biomiler in 10cm depth and water temperature  (30-11-2016)

This is how the Eco Shower/Biomiler looked on the 02-12-2016

Since we finished, the water temperature hasn't got under 43º C. 
It's a really good temperature for a shower, but there were days the water was too hot... 
So we manage to connect a cold water pipe that comes from the same water tank. By adding a T connector we get cold water before it gets inside the Biomiler.

We have used the shower now for ~2 months and it still have hot water.

Considering the size of this Biomiler, I hope it holds for 4-6 months with a temperature above 40º C. 


So keep updated :)