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Composting toilet

PermaTree composting toilet

The PermaTree compost toilet system explained

For our toilet system we do not use any water at all, because we have build a so called “compost toilet” which are water free. For most visitors at the farm, using a composting toilet is a first-time experience. This system which treats human waste by composting to produce a usable end-product that is a valuable soil organic material.


So instead of creating something called “waste” – we create something called a resource – organic material – a valuable and much needed soil fertilizer. You may not know but most soils in our region are very acidic and lack of organic matter. Adding fertilizer is the best option to increase production.

Also from another point of view – human feces are not a waste to be flushed away. Most importantly, because they are a valuable, nutrient-rich product when composted. Meanwhile, a typical water flush toilet system, the “waste” will decompose as sewage anaerobically. Thus releasing both methane and carbon dioxide into the atmosphere. Now composting toilets offset carbon emissions because they decompose aerobically – meaning with oxygen. 

It turns human excreta into compost over a process of decomposition of organic matter. Made possibly by microorganisms (mainly bacteria and fungi) under so called controlled aerobic conditions.

This compost toilet will only need dry material such as sawdust after each use. Both urine and feces are mostly water, but also high in nitrogen. For every one part of nitrogen to compost, it needs 30 parts of carbon; therefore a lot of dry material. The sawdust creates air pockets in the human excreta to promote aerobic decomposition. Additionally it  improves the carbon-to-nitrogen ratio and reduces potential bad odor. 

Inside the composting toilet tank, the material naturally heats up similarly to a garden compost pile. The heat kills off bacteria and the pile reduces in size, producing an odorless dry humus fertilizer.

Before using the compost, we keep the compost for a period of 12 month parked. To enable pathogen die-off. During this time we use the other compost toilet. And thats why we have two separate compost toilets with separate compost tanks.

And yes toilet paper is typically placed in the toilet. Therefore, the toilet paper will be visible long after the solid matter has broken down. Because paper does not decompose as quickly as solid wastes.

History of composting toilet

While basic water-based flushing toilets have been around since Roman times, waterless toilets are actually much older. As with many things, the origin of the earliest waterless toilets – composting toilets – come from China.

One of the most remarkable agricultural practices adopted by any civilized people is the centuries—long and well nigh universal conservation and utilization of all human waste in China… The storage of such waste in China is largely in stoneware receptacles … which are hard-burned, glazed terracotta urns, having capacities ranging from 500 to 1000 pounds.

F.H. King (American soil scientist), Farmers of Forty Centuries, 1911

One unusual feature of traditional Chinese agriculture, almost unbelievable to early visitors from the West, was the Chinese use of human waste as fertilizer for their agriculture. They were “fanatical recyclers”, recovering virtually all waste materials in their society. After an initial cultural shock at the idea, Westerners who heard of the practice would dismiss the concept as medically dangerous and probably resulting in serious chronic disease problems. Yet there is little historical evidence to support that conclusion, and in fact more than 40 centuries of evidence that suggests the practice was successful and sustainable. In light of the many other elegant inventions and methods of living that the Chinese gradually perfected, it is likely that the Chinese system of “night-soil” management was done in a way that largely protected public health.

The Chinese peasants use almost exclusively night-soil for manuring their fields. It is stored in large earthenware pots, either standing free or sunk in the ground up to their edges. In the latter case, privies are built over them. These, open to the public gaze, are not used by women. For the convenience of the latter a wooden bucket with cover is kept in the house, which is emptied into the free-standing earthenware pots out-side the house.

Rudolph P. Hommel, China At Work, 1939

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