You might say I am fond of Sweden and its Nobel Prizes. Now that the Mars500 shortlist includes also a Swede, there implies another delight: The Swedish Biogas might save the day for men and women in space missions.
Biogas for Mars? Biogas is simply a biofuel that is obtained when organic matter is decomposed biologically in the absence of oxygen. A typical biogas has the following composition in percentages:
Methane: 50-75
Carbon Dioxide: 25-50
Nitrogen: 0-10
Hydogen Sulfide: 0-3
Oxygen: 0-2
Hydrogen: 0-1
Higher methane content of 85 percent is reported in the Swedish Biogas. (1) Swedish companies have acquired several patents in their long pursuit of biogas, hence the Swedish Biogas. I have not studied these patents but I suspect that different methods are possible to some extent for different waste feed-stocks. To give you an idea of the variety, some waste types and their methane yields in cubic meters per ton of waste are listed below. (2)
Animal by-products (pasteurized): 225
Animal by-products (unpasteurized): 56
Slaughterhouse waste mixture: 160
Source-sorted household waste: 130
Manure: 13
Sweden is the place to visit at this time if you want to learn more about large-scale biogas production. I culled two important facts for you: (3)
1. Since the mad-cow disease outbreak, a biofertilizer obtained from the cow-slaughtering waste is not allowed for crops to be fed to cows.
2. Swedish law does not allow human waste in a biofertilizer for land use.
I am impressed with the steady progress in the biogas market in Sweden. They have done significant work in recycling of human waste, which should help with the ESA's Mars ambitions. I can conceive that there is some awesome science to bring to the table of biogas for space missions or just for better-living in our home planet.
Here comes my request for interest from you. My friends and colleagues: Be proud if you have already published your work with the key words 'human urine and feces' in a scientific journal or in a report. If you have not, humanity needs you! There might even be a future Nobel Prize for you and me.
(1) SBGF, SGC, and Gasfroningen handbook, Biogas from manure and waste products - Swedish case studies, Sweden, 19 May 2008.
(2) WestStart-CALSTART report, Swedish Biogas Industry Education Tour 2004: Observations and Findings, Brad Rutledge, Pasadena, California, USA, 12 November 2004.
(3) ibid.
