Secondary Treatment of Compost

The Bambooloo Toilet acts as a receptacle only and the actual composting of the toilet contents needs to be done in what is known as a secondary treatment area. That all sounds a bit technical but, like compost itself, it all reduces down to something incredibly simple.

Although composting is often referred to as a science, the truth is that it’s simply nature’s way of recycling materials. All the hard work is done by the micro-organisms and therefore your only job is to create the best possible conditions in order for them to function.

The key thing to get right is the amount of carbon material which is added to the system while in use. This relates to the common principle of a carbon to nitrogen ratio. Carbon refers to the cover material which we use, and the nitrogen component is comprised of human excrement in the toilet (both solids and liquids). Just like in garden compost, humanure composting also asks for an optimum ratio of 25-30 parts carbon cover material, to 1-part nitrogen. As a general rule, it is very difficult to add too much carbon material to your compost and if at any stage your toilet has problems with odour, the most likely reason is that you’re not adding enough cover material.

Recommended Cover Material

For the Bambooloo system, we recommend using a mixture of wood shavings and coco-peat as a cover material. The wood-shavings should be from a species of tree such as pine which is able to break down quickly, opposed to one such as cedar which is more resistant to decay and will take longer to break down.

The coco-peat in the mixture is more resistant to decomposition, but it will help to soak up and retain a lot of the moisture in the toilet, and when in the compost heap provide an ideal growing environment for the micro-organisms in the compost.

To work out how much of each material to use in your compost mixture, please use the table below.

Our recommended ratio is 50% coco-peat to 50% wood shavings. This allows for optimum retention of moisture within the toilet receptacle.

Building Your Composting Area

As you can see from the image above, compost bins and piles can be constructed in a range of ways. Ultimately, there is no specifically correct way and expert composters frequently argue over the best techniques and ideas for achieving great compost. To keep things simple however, we have designed a super simple system to achieve a good compost with very little labour required.

We recommend using a simple composting bin, which you can purchase via our website or from most good hardware or garden stores. If you do not wish to purchase one, also feel free to take a look online at some ideas for DIY compost bin solutions, including making them from pallet wood.

In optimum climate conditions (warm areas) you will most likely fill up a 300 litre bin within the space of a year. That’s one bin of humanure compost per person, per year. In colder climate areas this can greatly increase as the material takes longer to break down. To help speed things up, it’s best to position your bin in a place where it receives sunlight to help warm the contents and speed up breakdown of materials.

Larger compost bins are preferred if possible, as the size of the pile also relates to its ability to retain heat and maintain optimum composting conditions.

The composting bin is really just a formality. To be honest, you can simply create a pile of this material on the ground and it will compost and achieve a similar result. Purchasing a dedicated composting bin, or building a composting area will help to reduce unwanted insects and animals from being able to access the pile, as well as making it more visually appealing.

There is no reason your compost can’t have direct contact with the ground, and in many cases, this is actually beneficial as it allows for worms etc to also get into the system and aid in breakdown of materials once the initial composting has been done and the compost has cooled down from its thermophilic conditions. When starting your compost bin, it’s good practice to place a base layer of coco-peat into the bin, which can help to absorb any leachate that may be generated in the compost. If you’re concerned about leaching of excess moisture into the ground, then you are able to place it either on a concrete base, or plastic sheet but in this case, it’s good practice to build in a centre drain with a central soak-away for leachate to prevent anaerobic conditions from occurring.

Use and Maintenance of the Secondary Compost

Our Bambooloo comes with a supply of compostable toilet bags. As per the instructions, one bag at a time is placed as a liner to the bucket and is filled with pee, poo and cover material. Once your bag is full, it can be added to the compost bin / pile. The bag itself will take around 30 days to decompose, allowing for an initial breakdown of the materials to take place before it mixes with the other materials in the bin.

Once the bin has filled up (which will depend on the size of the bin, quantity of material being added and climate which can affect the speed of composting) add a top layer of cover material to the compost bin and then simply leave the material for 1-2 years to properly break down. You will know that the compost is ready once it has broken down to roughly 50% of its initial mass. Once the first bin has been filled, a second compost bin should be used for any new composting bags from the Bambooloo.

If your carbon and nitrogen ratios have been added correctly and if your compost pile is in a warm climate zone, then most likely you will achieve thermophilic (hot compost) conditions in your bin, and complete sanitation of materials will take place relatively quickly (within months). In the case that you’re in a cold climate, or if your compost pile doesn’t achieve thermophilic conditions, then a retention period of 2 years will ensure complete sanitation and death of all potential pathogens. If for whatever reason you’re not sure that the compost is ready, simply give it more time.

As a guideline, we recommend a minimum of 1-year maturation (after the bin is completely full). This ensures that the compost goes through all seasons, including the warmer months where hot composting is more likely to be achieved. It is possible to purchase compost thermometers to check how your compost pile is functioning.

With the composting process complete, you will now have nutrient rich compost that can be added to ornamental gardens as well as fruit trees and orchids. Many also use this rich compost material on vegetable gardens, though this is a matter of personal preference.

With the first bin now empty, you’re ready to re-start the cycle and begin filling with new material.

Find Out More About Composting

The above system is simple, and it works effectively. Of course, if you really want to get into it there is lots more that you can learn about composting and how to get the most out of it. For anyone who uses a humanure toilet, we strongly recommend the Humanure Handbook, which can be purchased, or read free online. Grab yourself a copy to learn all you ever will need to know about humanure composting.

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