Micro-aerobic Fermentation

January 8, 2012
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Used in sanitation, micro-areobic fermentation, and the related lacto-fermentation, avoids odor and loss of nutrients or carbon in the atmosphere. Micro-areobic fermentation of both urine and feces a bacterial mixture. Researchers Ralf Otterpohl and Hector Factura (see Otterpohl 2009 and FACTURA et al. 2010) say it is easily obtained by taking an inoculum from Sauerkraut liquid or purchased commercially.  Mixes known as EM (for ” effective microorganisms”) includes  natural lactic acid bacteria, yeast, and other bacteria that ferment and accelerat breakdown of organic matter.

Faeces are first covered, according to Otterpohl, with a mix of charcoal and saw dust which facilitates later vermiculture. The microbial mix can be added after each deposit or when the poo bucket is full. A minimum month of fermentation in a tightly closed container readies the bucket for vermicomposting.   For the urine,  half-quart of mix is used to ferment a tightly sealed jerrycan over a month’s time.  Fermentation avoids release of  volatile ammonia and CO2.  Odor is controlled and  N retained in the urine to enhance its qualities as a fertilizer.

This process builds more effectively builds substrates for soil food web as compared to traditional hot (aerobic) compost piles where CO2 is immediately gassed off.  The technique is by storing compostables in closed containers, which can be applied to poo buckets from post-disaster emergency toilets.

Key resources

Turnover of Carbohydrate-Rich Vegetal Matter During Microaerobic Composting and After Amendment in Soil.   Terrence R. Green of TGA LLC and Radu Popa of Portland State University describe the process.  Even when a closed container is used, there is enough oxygen that leaks in to consider it micro-aerobic versus anaerobic where is completely absent of oxygen. Wheat bran was the inoculate. The intro and discussion in this highly technical open source article are valuable.

Bokashi Food Waste and Pet Poop Disposal – Chemical Analysis and Biology   Pathogen reduction trials on pet feces with this technique have also been done.  Tom Carter with Agua Pura para el Pueblo  is Portland area source for simple fecal coliforms and E. Coli test kits used in pet waste study.

“Lactic Acid Fermentation” Paul Oliver’s excellent short introduction to rationale for process and simple technologies.

“Terra Preta Toilets”  In Sustainable Sanitation and Water Management (SSWM) Toolkit.  by Dorothee Spuhler and Robert Gensch.

Reckin, J. 2010 New Insights in matters of Plant Nutrition, Soil Microbes and their role in Recycling of Human Excreta and regenerating Soil Fertility.   Sec 3. discusses the microbial mix.

 Lactic Acid Fermentation  Wikipedia overview.

Bokashi food scrap composting uses lacto-fermentation is becoming popular at the household level. Instructions and supplies from Bokashicycle,  BokashiComposting and ProKashi among many others.

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    Public Hygiene Lets Us Stay Human, or PHLUSH, is an all-volunteer advocacy group based in Portland's Old Town Chinatown. We collaborate with grassroots organizations, environmental activists, planners, architects, code officials and city managers. We receive support from the Old Town Chinatown Community Association and Neighbors West-Northwest. PHLUSH is a member of the World Toilet Organization and a partner in the Sustainable Sanitation Alliance.

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