Thursday, March 11, 2010

Separation Toilet for Liquids and Solids - Practical or Not?

Europeans rally behind the 'NoMix-tech' toilet
Elizabeth Armstrong Moore

The NoMix toilet, which rather appropriately collects urine in the front and faeces in the back, has gained wide support by consumers throughout seven countries in Europe as a means of reducing pollution and conserving water, according to a new paper by scientists in Switzerland.

"NoMix" toilets, collect urine and faeces separately.

The just-publicized article, which calls on authorities to push for early adoption of the high-tech toilet, appears in the semi-monthly journal
Environmental Science & Technology by ACS Publications.

Of the 2,700 people surveyed in Switzerland, Germany, Austria, Luxembourg, the Netherlands, Sweden, and Denmark, 80 percent say they support the idea behind the technology, and between 75 and 85 percent report that the design, hygiene, smell, and seat comfort of the NoMix toilets equal that of conventional ones.

Moreover, roughly 85 percent say they are open to the idea of using stored urine as fertilizer.
Judit Lienert and Tove Larsen write that the toilet collects urine separately, with the main advantage being that urine contains 80 percent of the nitrogen and 50 percent of the phosphorus that arrives at wastewater treatment plants. Those two elements trigger such things as algae blooms that can enter waterways and threaten fish.

Apparently, a full decade into the 21st century, the rather simple NoMix model is a relatively novel technology whose acceptance (beyond the NoMix-loving Swiss) had not been scientifically measured until now.

partially sourced from

This all sounds wonderful, except that in countries like Australia where low flow units are common, it is already an issue that total liquid flows down the sewer pipes can be too low for effective effluent transfer. That is, liquid is needed to get the waste from your place to the treatment location.

Maybe in hilly Switzerland it all goes downhill..........

These systems sound wonderful, but practical issues like that above need to be considered too.

There are systems that use on site composting with liquids separation........that would be a suitable option too, that avoids waste transfer. There are many other options, and most are practical and fit in with existing technology.

One of these is the Gough Hybrid Toilet. A low flow unit originally designed for small island communities with poor water supply, it has also been extensively used in toilet facilities designed for roadside and resort use in remote areas, as well as holiday homes or in areas with low water supplies. On site treatment is used, the output is predominantly liquid and can be reused for irrigation. See

The concept of better toilets is not new, but is a separation model the best option? Not always the ideal would be my view, and there are many options.

The current Australian concept of a dual option, low volume flush [ commonly 6L/3L with a suitable pan design] would seem a simple solution when combined with low health risk effluent treatment and recycling.

1 comment:

Agricultural Investments said...

Nice article Elizabeth and I agree with your views.The separation toilet needs no water, chemicals or additives. By separating urine, the capacity for collecting solids increases. Urine is germ-free, provided that human kidneys function well. It is rich in plant nutrients such as nitrogen and phosphorus.