Often times the digestate (solids left over after anaerobic digestion) is land applied as fertilizer as it is very high in potassium as well as nitrogen (and usually salts too, slightly less appealing).
Other times it’s composted then used as, well compost. This is common practice in California cities such as Oakland that anaerobically digests biosolids (poop) at their wastewater treatment plant. As long as the digester really cooks (131 fahrenheit for 3 days) pathogen kill is achieved and any “threat” is gone.
In which case I would argue that our excrement makes exactly ZERO pollution when processed appropriately.
At enclosed or within-vessel composting process operations and
facilities, active compost shall be maintained at a temperature of 55
degrees Celsius (131 degrees Fahrenheit) or higher for a pathogen
reduction period of 3
days.
Thanks Curtis.
Jeremy
ps - an exciting tangent on the Oakland thing is that they are now co-digesting commercial food scraps collected by the city in the WWTP digesters. Now that is some GHG reduction AND methane power!
Note: vegetative food scraps are also very high in nitrogen....
On Aug 20, 2010, at 4:02 PM, CURTIS BLANKINSHIP wrote:
This is a link to a small scale methane digester. the extra water tank is used to create pressure to use the gas for cooking or powering a generator.
does everyone get that we can produce power from our own excrement with very little pollution. This would get us back withing earths cycles ( see Nitrogen cycle ) instead of working against them which enables a small group to maintain power.
Curtis
http://www.youtube.com/watch?v=l5e_2W71jMM