The Challenge


How can we improve sanitation and better manage human waste in low-income urban communities? read the brief


The X-Runner

This is a really interesting urban slum sanitation concept . The X-Runner is a practical toilet and sewage system for the third world. The unit can flip up and be rolled, to a local Biogas Plant where it can be turned into electricity.
Concept by: Noa Lerner


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Linda Foss

July 09, 2013, 19:21PM
It looks like a great concept, but it isn't very big. Am I missing something?

Sabra Marcroft

December 29, 2010, 22:24PM
Financially successful biogas programs make use of large amounts oflivestock manure mixed with human feces to maximize biogas production.Livestock manure will do just fine by itself, but human manure needs some help to perform. Even if there is not enough livestock manure available to really increase biogas production, it still makes sense to produce biogas, because it is such a cheap and effective way to sanitize and compost the feces.

Vincent Cheng

December 29, 2010, 22:12PM
Nice analysis Ossian. Gives us a better sense of the #'s we are dealing with, and what's currently realistic. Would be interesting to see how the figures work out based on local energy prices/demand in Kumasi. Also, anyone have any idea of the Ghana market for other human waste products like fertilizer?

Ossian Hynes

December 29, 2010, 20:29PM
Humans produce roughly 500 litres of urine and 50 litres of faeces per person per year. These contain about 4 kg of nitrogen, 0.5 kg of phosphorous and 1 kg of potassium, the three basic elements for plant growth. The exact amount varies from region to region depending on food intake. Seventy per cent of the nutrients excreted by humans are in the urine fraction.

Read more:

The amount of biogas that can be yielded from human waste is limited in comparison with livestock manure and other feedstocks. Our stomachs are just too efficient! David House states in his excellent book that 1000 lbs (I don't know if this is urine and and feces or just feces)of human waste produces about 0.6 cubic meters of biogas (enough cooking fuel for about 1 to 2 persons).

The price of natural gas varies greatly depending on location and type of consumer. In 2007, a price of $7 per 1,000 cubic feet (28 m3) was typical in the United States. The typical caloric value of natural gas is roughly 1,000 British thermal units (BTU) per cubic foot, depending on gas composition. This corresponds to around $7 per million BTU, or around $7 per gigajoule. In April 2008, the wholesale price was $10 per 1,000 cubic feet (28 m3) ($10/MMBTU).[39] The residential price varies from 50% to 300% more than the wholesale price. At the end of 2007, this was $12–$16 per 1,000 cu ft (28 m3).[40] Natural gas in the United States is traded as a futures contract on the New York Mercantile Exchange. Each contract is for 10,000 MMBTU (~10,550 gigajoules), or 10 billion BTU. Thus, if the price of gas is $10 per million BTUs on the NYMEX, the contract is worth $100,000.

So 0.6 cubic meters of gas roughly equals $0.32.

550 litres or urine and feces would weight around 550kg which would equal 1210lbs which would roughly give 0.7 cubic meters of buiogas which would roughly give $0.40. This is the average value of a years supply of sewage from one person given that human waste as defined by David House is urine and feces if not this number is roughly a tenth of that so $0.04.


The $0.04 is probably more accurate as urine probably won't be collected.
Can economies of scale make thias a viable job for someone. What is the average wage in some of the third world countries we're looking at?

I'm late for the cinema! Oops.

Sabra Marcroft

December 04, 2010, 10:49AM
Could we have a version of the x-runner for sale in the developed world? It would make a great remote camping or off grid cabin toilet. Proceeds from its sale could easily fund making its purchase more affordable in the rest of the world....

Andy Narracott

November 26, 2010, 16:37PM
The crux of this idea is turning human waste into cash, so the critical part of the chain seems to me to be the biogas plant. (My experience in many slum areas is that human waste currently flows everywhere - in pieces of waste land, on the railways, in the open drains outside people's homes - so the incentive to dispose of the human waste at the biogas plant needs to be real.) Hence, the vital part of the chain is the biogas plant. Anyone have any financial data on biogas plants, in terms of: payback from electricity sales - payback of capital investment - running costs = profit?

Danny Alexander

November 24, 2010, 21:42PM
I second all of the previous comments. It's great that the whole ecosystem has been considered, and that the waste can be sealed inside for safe, discreet transport.

Vincent Cheng

November 23, 2010, 17:44PM
Wow, really simplifies the toilet down to its essence, so that its space saving, easy to transport for processing, and affordable...impressive.

Adriana Olmos

November 23, 2010, 16:23PM
Yes, I agree this is a beautiful project. If someone is interested in supporting this project directly there is a way to do so through this website:

Meena Kadri

November 23, 2010, 13:56PM
I like that the entire product ecosystem has been considered and also that there are opportunities for entrepreneurial interaction.

Jocelyn Wyatt

November 23, 2010, 06:59AM
This is a great concept. The small footprint this would take up in a house is really attractive.
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