The results to date of a necessary addition to a village house and I wholeheartedly recommend the project to anyone thinking of upgrading their toilet disposal facilities. I opened the filter tank today to check progress and was delighted to see only the layer of shavings and no other deposits.
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Not a pleasant subject but a necessity.
It’s called a “digester toilet “
The solid waste is broken down naturally by the enzymes in the sawdust. This system has some commonalities with the composting toilet system except that the normal flush system is used. After 6 months of use it has proved to be an excellent choice of project as even when opened, there is no smell, no solid waste nor any indication of any problems.
The old “hole in the ground” for the toilet waste to go into with its “natural” drainage was far outdated.
I decided to build a simple, cheap, modern waste disposal system which needs virtually no attention. After only a couple of years, the old one needed emptying as it no longer soaked away and was full to the brim. This has been left covered and unused for the past 6 months and has eventually dispersed and been filled with garden soil
I opened the toilet filter tank today to check progress and was delighted to see only the layer of shavings and no other deposits.
The raw input from the toilet is directed onto the top of the planings.
My New Digester Toilet System
My new version was built on a system which is recommended by world authorities for Indian and African villagesand has gained a high reputation in places like Ghana. This consists of two excavations. Neither of them are deep holes, however, in my case, I decided that one hole with an internal step would suffice although it’s difficult to see in the photo.
The two block units are of a similar size. I have a tank made from concrete blocks which is about 1.75 meters long and 1.2 meters wide which I skimmed on the inside and added a solid cement floor. I managed to get hold of 6 discarded black plastic fruit crates and I placed them upside down, with fly screen as used over house windows, covering them as a filter. On top of this is added one full sack of wood planings.
These plastic baskets used for fruit are available at most shops as giveaways in two sizes. I found that 6 of the smaller ones filled the filter chamber almost perfectly and if you get your baskets first, the filter can be designed to take them. They are inverted as seen in the photo of course.
Beer crates would also be an excellent choice but in any case, strength doesn’t matter as they only hold a layer of wet sawdust or shavings. If you use beer crates, remember to empty the crates first (though I don’t think many people would need to be reminded of that).
This first tank has a drain from the side at the bottom which runs into the second tank which is set deeper into the ground by about 50 cm.
The photo shows the filter tank or bed with the inside skimmed and the concreted floor
Connecting the Soakaway
The drain from the filter tank is virtually only water as it is filtered by the sawdust and the fly screen into the space afforded by the plastic fruit baskets, which then runs from the draining pipe into the second toilet tank.
I took this photo before I finished the filter. The missing blocks are to enable me to get in and out to cement the floor. The total depth of the whole pit at the deepest point is only about 1.5 metres.
The filter tank with the digester toilet input waste pipe from the toilet.
The wood shavings contain a natural enzyme which breaks down toilet solids and continues to do so as infinitum. Yes, you can put toilet paper in there and it will be broken down.
Ground Work
The hole is shallow compared to the simple smelly hole in the ground type toilet which eventually needs emptying. This is approximately 2 meters square and stepped at one meter and 1.5 meters.
The filter with the built soakaway. The water from the filter goes into the soakaway at the top row of blocks, the soakaway consists of three rows of blocks with 5 cm gaps between each block to allow water to pass into the rocks I eventually placed in the space around the soakaway tank. This has the benefit of increasing the soakaway area outside of the tank which is only there to give the water somewhere to go before soaking into the ground. If this is not done, there is a danger of the water exiting the filter and backing up into the filter.
Soakaway Tank
This second tank has no floor and although it is made from blocks, the 5 cm gaps between each block allow water to flow freely outside of the tank for better distribution and a greater soakaway area.. Outside this “tank”, I filled to its full height with rocks. As water runs from the filter tank into the soakaway, it has the full floor area plus there is no restriction for it to run through the slots in the sides of the soakaway tank made from the 5cm gaps between the blocks and into the rocks.
The top of this tank is covered by several layers of discarded corrugated roofing sheets for strength as the intention was that the top of the soakaway would be covered with garden soil removed from the pit in which the soakaway stands.
The whole of this tank including the corrugated sheets, is about 25 cm below garden level so was covered in black plastic polythene sheet (including the rocks) and filled to garden level with soil. I left the first tank proud of the garden by only a few cm for inspection purposes. The filter bed was built on the one-meter section of the stepped hole and the soakaway in the lower portion.
Kitchen and Shower
The thin pipe is from the kitchen sink, shower and washing machine directly into the soakaway tank
The pipe is level with the floor and the floor is inclined so that any water on the floor is directed out of the pipe.
As can be seen, the pipe is at least a half meter above the floor of the lower portion of the pit.
Unfortunately, I didn’t take photos of the inside of the filter before I finished it, but it has a single layer of the ubiquitous black plastic fruit crates which are upturned and covered by a double layer of green nylon fly screen. On top of this, I emptied a full sack of wood planings free from my friendly local carpenter.
The only photos I have of the finished interior with the wood shavings and the inlet pipe. Notice that the plastic crates to create a space beneath the filter, take up the space shown in another photo where a shelf can be seen inside.
The soil pipe from the house goes into the filter near the top and empties above and into the wood planings.
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The site was finally covered and a waste piece of canvas was placed over the filter to check for correct operation after a few days.
Finishing the Job
The blue canvas cover of the filter has been discarded and several ceiling boards rescued from the local fly tip now cover the top. At a later date (when I’m not feeling lazy) the top will be covered by a pair of cast concrete lids which will be sealed to prevent my dogs from breaking through and falling – perish the thought!
