Terra Preta do Indio (black soil of the Indians) is the anthropogenic black soil that was produced by ancient civilizations in the Amazon region by converting biowaste and faeces into long-term fertile soils. These highly productive soils maintained high amounts of organic carbon even after being left unused for several thousand years. The discovery of these anthropogenic ancient soils opened doors for the possibility of a highly efficient sanitation system and thus, the Terra Preta Sanitation system came into being.
The Terra Preta Sanitation concept focuses on sustainable management of natural resources and emphasizes on safe treatment of human waste to address some big challenges of our society, which include poor sanitation, food crisis and soil degradation. Developed by TUHH Hamburg University of Technology, Hamburg, Germany, the Terra Preta Sanitation system is based on urine diversion and the addition of charcoal in order to produce long-lasting and highly fertile soils that boast properties similar to that of the lately discovered manmade terra preta soils. The system makes use of natural processes of lacto-fermentation and vermicomposting to convert faecal matter into Terra Preta like soils for agricultural use.
A TPS toilet system collects the urine and feces in two separate compartments. While the urine goes into jerrican, the feces collect in an airtight bucket positioned below the toilet bowl to make for anaerobic conditions inside the bucket. The feces need to be covered with a mix of charcoal powder combined with a wood source and some limestone or volcanic soil. A little bit of Lactobacilli containing microbial mix, also needs to be added. The same triggers a lacto-fermentation in the bucket and since, there is no methane produced to cause odors, the system could be used on large scale in urban areas.
After each use, the users have to close the toilet lid to allow for good anaerobic conditions. The bucket, when filled, can be kept aside in closed condition for around a month. Finally, it would be treated with micomposting process, which gives us the highly fertile Terra Preta soil. The TPS can treat both human excreta and organic household waste.
Last year, a slum-suitable toilet designed by Sabine Schober from Hamburg won the 2012 WTO International Toilet Design Award. This toilet combines sanitary comfort with Terra Preta Sanitation system using the hygienized excreta after mixing with charcoal for the production of highly fertile soils.
- The WTO Toilet Design winner
The Terra Preta Sanitation (TPS) can prevent nutrient/carbon loss to the atmosphere by producing highly fertile Terra Preta soil and liquid fertilizer for agriculture. The system takes in faecal matter, sludge, brown water, black water, yellow water, urine and organic solid waste, and produces compost or biosolids. Although quite promising, TPS is a relatively new technology and requires more research.
- Terra Preta Sanitation – An Overview
This video about Terra Preta Sanitation (TPS) by Andreas Swensson at the Institute of Wastewater Management and Water Protection at Hamburg University of Technology was made under the direction of Dr. Ralf Otterpohl.
The 1st International Terra Preta Conference (August 29-30, 2013) will be held at Hamburg University of Technology. The goal is to bring together experts from the different sectors – water and sanitation, agriculture, soil, energy and health – to present their research results and share their views about the Terra Preta Sanitation.