Emergency digesters for a human world
Pictured in alarming detail above is a sample of Escherichia Coli bacteria. These live inside you. They belong in your lower intestine where they provide digestion services in exchange for room and board. In your gut, they actually prevent disease by out-competing other bacteria and fungi. Where you don't want E. Coli is in your drinking water.
There is an earthquake - a tsunami - a hurricane - a war. Something has swept over an organized group of a million people and royally messed things up! Generally what happens next is this: sewage into the drinking water. In the weeks and months, following disasters, a disproportionate number of deaths can be directly attributed to bacterial contamination of drinking water. Waterborne bacterial epidemics tend to amplify themselves, as more and more sick people without toilets take to open deification - putting more bacteria into the water for everyone.
If the disaster region is lucky enough to receive help, often times portable toilets are brought in and the waste is removed to a treatment plant elsewhere until the local system can be fixed. The not-so lucky regions do what they can, but that almost always ends up just being an open lake of effluence seeping into the water table...
A really good solution that needs to happen:
Wherever there is a human disaster, deploy biodigesters, and then pay people for their waste.
What is a biodigester?
A biodigester is an old idea that has been used with great success in many parts of the world. Typically, it is a covered basin of some sort wherein animal waste decomposes and produces methane gas. The methane is then used for cooking, lighting, electrical generation, and boiling of water. Many are made out of brick or clay or concrete, and are situated in the ground on a farm. Not exactly portable.
The type of biodigester that I recommend developing into an humanitarian aid solution is the bag or balloon type digester. The essential technology is nothing more than a long plastic bag - think of it as a giant intestine. Dangerous biologically active waste goes in one end, anaerobic digestion takes place through its length, and harmless fertilizer comes out the other end. Methane gas percolates out and can be tapped from the top of the bag. The gas can be used for heating, cooking, electrical generation, and again, purifying water.
Why pay people?
Because it means the waste will not be dumped into the water table. Disasters are terrible for local business and commerce is typically suspended along with all other aspects of normal life. In any group of people, there is always an entrepreneurial component that means some people will be motivated to collect other people's waste and deliver it to the digested for pay. Relief funding would be well spent to reimburse local waste collectors. It does not have to be an outlandish reimbursement, but it must be enough. Enough is based on local economics. In addition, the program should provide the means of collection, such as buckets, portable toilets, and car-table tanks.
A deployed and collection-incentiveized biodigester is Win-Win-Win. First, the harmful human waste is sequestered and kept out of the water table. This greatly reduces many of the after-disaster diseases. Second, an economy of collection lays the foundation for a restart in local commerce and establishes a network of local participation in the recovery. Finally, the sequestered waste is up-converted into energy and fertilizer. The energy would be directly useful for emergency hospitals, kitchens, and communication centers. Once other parts of the local economy have stabilized, digester products could be monetized, creating a self sustaining business and paying for the local collection services.
I have not found any examples of biodigesters being used as deployable humanitarian systems as of yet. The technology, however, exists. Plastic bags can be made, and they are NOT expensive. The simple act of impounding the bulk of human waste has immediate benefits. Beyond that, the system will begin to deliver those secondary economic and tertiary energetic benefits as well. If you are part of an aid organization and want to develop this idea, please contact me, I would love to participate. I feel like this is the most important & clear-thought I have ever had about technology and people.
Saskatchewan Research Council website:
ECOFYS video about bag type digesters
Build A Bio-Gas Plant tutorial page
An entry in Energypedia
Book: The Biogas Handbook by David House