Lacto-fermentation is a biological anaerobic process, although lactic acid bacteria can continue to grow if oxygen is present. Used in sanitation it avoids odor and loss of nutrients or carbon in the atmosphere. Lacto fermentation of both urine and feces a bacterial mixture. 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.
Key resources
“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.
