A urine based 'potion' can act as a CO2 absorbent (w/ Video)

August 17, 2012

The ocean, the ground, rocks and trees act as carbon drains but are far from places where greenhouses gases are concentrated, especially CO2. A Spanish researcher has proposed human, agricultural and livestock waste, such as urine, as a way to absorb this gas.

Absorbing the large quantities of and other present in cities would require millions of tonnes of some naturally occurring substance. A study published in the suggests urine as a reactive. As a resource available across all , it is produced in large quantities and is close to the hubs of large cities.

"For every molecule of urea in urine, one mole (a chemical unit used to measure the quantity of a substance) of ammonium bicarbonate is produced along with one mole of , which could be used to absorb one mole of atmospheric CO2," as explained to SINC by the author of the study, Manuel Jiménez Aguilar of the Institute of Agricultural and Fisheries Research and Training of the Regional Government of Andalusia.

After absorbing the CO2 another unit of ammonium bicarbonate is produced, which is used in China as a nitrogen fertilizer for 30 years. Jiménez Aguilar points out that "if applied to basic-calcium rich soils this would produce calcium carbonate thus encouraging gas-fixation in the ground.

To avoid the urine from decomposing, the researcher suggests the possibility of including a small proportion of olive waste water (a black, foul-smelling liquid obtained from spinning the ground olive paste). This acts as a preservative. The researcher confirms that "the urine-CO2-olive waste water could be considered an NPK fertilizer (ammonia-nitrate-phosphorous-potassium)."

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A Spanish researcher has proposed human, agricultural and livestock waste, such as urine, as a way to absorb CO2. Credit: SINC

The result is that the urine mixed with a small percentage of olive waste water can absorb various grams of CO2 per litre in a stable manner and over more than six months. According to Jiménez Aguilar, "CO2 emissions could be reduced by 1%."

The fluid created can be inserted into domestic and industrial chimneys (reconverted into containers to accumulate the urine-olive waste water mixture) so that the greenhouse gas passes through the liquid, increasing the pressure exerted on the CO2 and thus increasing its absorption capacity.

As the scientist makes clear "these containers or chimneys should have a urine filling and emptying system and a control system to detect when the mixture has become saturated with gas." When taken out of the chimney, the urine is stored in another container or can be channelled for its distribution and use as an agricultural fertilizer.

Making the most of urine

By applying this methodology as a greenhouse gas absorbent, the way in which industrialised countries use waste water and solid waste would never be the same again. The author hints that the whole water and waste treatment system would be reviewed to adapt newly built areas to a waste recycling and waste management system.

"In developing countries this nutrient recovery system could be implemented thanks to its environmental advantages," says the expert.

Furthermore, urine recycling in every home would allow for nutrients to be recovered, leading to a lesser need for artificial fertilizers. Jiménez emphasises that "if urine and faeces are recycled there and then, as much as 20 litres of water per person per day could be saved and this would reduce waste water treatment costs."

The study suggests that urine should be recycled for it to be used as fertilizer liquid and that faeces should be treated with solid organic waste to produce compost or solid fertilizers. The researcher also states in another study that is pending publication that the -olive mixture can also be used to reduce the CO2 and NOx emissions of vehicles.

Explore further: Human urine as a safe, inexpensive fertilizer for food crops

More information: Journal of Hazardous Materials 213: 502-504 DOI: 10.1016/j.jhazmat.2012.01.087, 30 April 2012.

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1 / 5 (2) Aug 17, 2012
Did you know that on buildings with green roofs of oxidized copper, urine is pored on the copper to make it green? Traditionally the workers collected the their own urine.
1 / 5 (1) Aug 17, 2012
I've thought about use ammonium solution to trap CO2 and under anaerobic conditions, micro-organisms are able to convert the ammonium carbonate (or bi-carbonate) to urea. Urea can be crystalized and collected as solid for easy storage and transportation. Urea will finally be used as fertilizer.
not rated yet Aug 17, 2012
Collecting pure urine would be costly.
not rated yet Aug 17, 2012
Collecting pure urine would be costly.

A porcelain pot with a fume trap connected to a pipe leading to a tank.

Separate devices for urine and feces might increase the size of bathrooms (mens' public restrooms already contain urinals and toilets) but arguing that it would be too expensive compared to the real price of food without the "cheap", unsustainable fossil fuel-based fertilizer subsidies we now use, does not hold water.

Several runs of plumbing in every house might in fact add initial construction costs-- one for urine, one for feces (which might require small quantities of water), and one for so-called grey water (everything else-- from baths, clothes/dishwashing, etc) to use for watering fruit trees, gardens, and beneficial insect and bird habitats in urban settings. But all this, along with reducing loads on sewers and wastewater treatment, carbon reduction and renewable fertilizer (especially phosphates!), it looks like win/win natural technology to me.
1 / 5 (3) Aug 17, 2012
Collecting pure urine would be costly.

A porcelain pot with a fume trap connected to a pipe leading to a tank.

I think this article is a practical joke.

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