The Waterless Toilet Nutrient Cycle

As we have seen water borne sanitation is expensive, not just in terms of financial resources, but also in its environmental cost.

Waterless sanitation and waterless toilets can contribute to a safe way of re-cycling valuable nutrients.

The pit toilet is the oldest form of waterless toilet (use of the veld is older, but is that a toilet?). The waste can be emptied from the pit and used in the fields; in practise this is not done due to the unpleasantness of the job of handling fresh faeces.

There are other forms of waterless toilets, both traditional and non-traditional.

In principle the end product from waterless toilets are to be recycled in the fields, in order to return the valuable nutrients to the soil. The aim of any system should be to mitigate the pathogen content of the waste, while enabling the user to easily use the decomposed product.

There are composting waterless toilets of varying degrees of sophistication. There are waterless toilets where the pedestal is moved and the user is encouraged to plant a tree on the old site. There are waterless toilets that even microwave the faeces to rid it of all pathogens.

SolarSan waterless toilet separates the urine from the faeces and dries the faeces with the aid of wind and sun. Urine is a natural fertiliser rich in nitrates, potassium and phosphate. As such, one of the worst things that one can do is mix it with pathogen rich faeces; the urine then acts as a food for the pathogens, making it that much harder to render the waste safe.

Why Waterless Toilets?

Using water to aid the passage of excreta away from the producer of such waste – though importantly not the treatment of such waste – is an historical anomaly.

It could be argued that Thomas Crapper (and his development of water borne sanitation) has saved more lives than any other person. The London sewer system was developed in response to cholera outbreaks and other public health problems. One of the main reasons that water borne was chosen is that it was a cheap and practical way to move the sewerage away from the population centre. It was cheap because it used the considerable existing infrastructure of storm drains.

There is no particularly good reason why sewerage should be transported away from the producer by the use of water. There are indeed many bad reasons.

The looming water crisis

This has been well documented elsewhere, but it is worth re-iterating. There are increasing water problems in many parts of the world – developed and developing. This is often due to degraded quality, but also due to an increasing pressure of demand on a limited resource.

There are presently about 1.1. billion people who lack access to a safe water supply. The world population is predicted to grow by about 2 billion in the next decade, most of whom will be in developing countries, which have the most profound water problems. It is entirely feasible that the future wars will be over water rather than oil; indeed securing Israel 's water supply plays more than a minor part in the present struggle for the Golan Heights .

Water borne sanitation is not the major user of water (farm irrigation is), but is a significant user. Waterless toilets could contribute in no small way to both an appreciation of water as a limited resource and to an alleviation of the demand.

Expense

The pressure on most cities by urban migration and natural population increase means that few can maintain their sanitation infrastructure to keep up with demand. This is not merely the water reticulation, but more importantly the sewerage farms and other tertiary treatment centres. We all want to flush and forget, but in many parts of the world this is neither a practical nor affordable option. It is estimated that 90% of wastewater worldwide is either treated unsatisfactorily or discharged with no control.

Because of the difficulty of treating water borne sewerage effectively, there are many instances where the overloaded sewerage farms are actually contributing to public health problems rather than alleviating them. This can be caused by a general shortage of water, which might only be available for a few hours per week, or conversely too much water and overload of the system. The recent outbreak of typhoid in Mpumalanga seems to have happened because of an overloaded, flooding sewerage farm.

Conclusion  

Waterless toilets can contribute to public health, the public and private purse and environmental health. Moreover, the waste from waterless toilets is an effective and free form of fertiliser.