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History and Technology of Terra Preta Sanitation Sustainability 2014, 6, 1328-1345; doi:10.3390/su6031328 OPEN ACCESS sustainability ISSN 2071-1050 www.mdpi.com/journal/sustainability Article History and Technology of Terra Preta Sanitation Sabino De Gisi 1,*, Luigi Petta 1 and Claudia Wendland 2 1 Italian National Agency for New Technologies, Energy and Sustainable Economic Development, ENEA, Water Resource Management Lab., via Martiri di Monte Sole 4, Bologna (BO) 40129, Italy; E-Mail: [email protected] 2 Women in Europe for a Common Future, WECF, St. Jakobsplatz 10, Munich 80331, Germany; E-Mail: [email protected] * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +3-905-160-989-26; Fax: +3-905-160-983-09. Received: 12 December 2013; in revised form: 30 January 2014 / Accepted: 4 March 2014 / Published: 12 March 2014 Abstract: In order to reach the Millennium Development Goals for significantly reducing the number of people without access to adequate sanitation, new holistic concepts are needed focusing on economically feasible closed-loop ecological sanitation systems rather than on expensive end-of-pipe technologies. An analysis of a former civilization in the Amazon (nowadays Brazil) highlights the possibility to close the loop with a more sustainable lifestyle integrating soil fertility, food security, waste management, water protection and sanitation, renewable energy. Terra Preta do Indio is the anthropogenic black soil produced by ancient cultures through the conversion of bio-waste, fecal matter and charcoal into long-term fertile soils. These soils have maintained high amounts of organic carbon several thousand years after they were abandoned. Deriving from these concepts, Terra Preta Sanitation (TPS) has been re-developed and adopted. TPS includes urine diversion, addition of a charcoal mixture and is based on lactic-acid-fermentation with subsequent vermicomposting. Lacto-fermentation is a biological anaerobic process that generates a pre-stabilization of the mixture. The main advantage of lacto-fermentation is that no gas and no odor is produced. What makes it particularly interesting for in-house systems even in urban areas. Instead, vermicomposting is an aerobic decomposition process of the pre-digested materials by the combined action of earthworms and microorganisms. It transforms the carbon and nutrients into the deep black, fertile and stable soil that can be utilized in agriculture. No water, ventilation or external energy is Sustainability 2014, 6 1329 required. Starting from ancient Amazonian civilizations traditional knowledge, the aim of this work is to present TPS systems adopted nowadays. Keywords: biochar; ecosan; nutrient recovery; reuse; sustainability; terra preta; traditional knowledge 1. Introduction The modern misconception that human excreta are waste with no useful purpose has resulted in the end of-pipe sanitary systems that we have today. In nature however, there is no waste. All products of living things are used as raw materials by others as part of a cycle. “Considering the environmental damage, the health risks, and the worsening water crisis, resulting from our present sanitary practices, a revolutionary rethink is urgently needed if we are to correct this misconception. In this way we realistically have a chance of achieving the Millennium Development Goals (MDG) of providing sustainable sanitary services to over 1.2 billion people” [1]. In light of the current discussion around the post-MDG and targets for sanitation, there is a strong will to include a requirement for the re-use of human excreta in agriculture into the new term “adequate sanitation” replacing the current insufficient term “improved sanitation” [2]. A new paradigm is required in sanitation, based on ecosystem approaches and the closure of material flow cycles rather than on linear, expensive and energy intensive technologies. This paradigm must recognize human excreta and water from households not as a waste but as a resource that should be made available for reuse [3]. Such ecological sanitation systems are based on the systematic implementation of the reuse and recycling of nutrients, organic matter and wastewater as a hygienically safe, closed-loop and holistic alternative to conventional solutions. Moreover, ancient water and wastewater technologies may have the potential to furnish “new” and sustainable solutions relevant to the current global environmental crisis [4]. In fact, many features of ancient systems (including no power requirements, use of locally-available materials and low or absent mechanization) mean they are arguably suitable for utilization as low-cost and low-maintenance water and sanitation technologies (WATSAN), particularly in the developing world [5]. Therefore, it is important to analyze and rediscover the ancient traditional knowledge using them for the new challenges such as the sustainable management of natural resources. The sustainability of societies depends essentially on secured water resources, food supply and an intelligent management of wastes. Food, for example, is produced with extensive input of energy and resources while nutrients are detracted from soils and needs to be replaced. Generally, replacement is often done by artificial fertilizers, which are produced with high energy input. In addition, the reduction of organic matter content by the degradation of humus is mostly not replaced to the required extent. A slow but steady degradation of soil as well as a loss of fertility are due from these reasons and pose a severe risk to long term food security worldwide [6]. In this context, the objective of this study is to present Terra Preta Sanitation systems (TPS) adopted nowadays also investigating the traditional knowledge of the ancient Amazonian civilizations. Sustainability 2014, 6 1330 2. History of Terra Preta An analysis of a former civilization in the Amazon, nowadays Brazil (see Figure 1), reveals concepts which enable a highly efficient handling of organic wastes. Terra Preta do Indio is the anthropogenic black soil that was produced by ancient cultures through the conversion of bio-waste and fecal matter into long-term fertile soils. These soils have maintained high amounts of organic carbon even several thousand years after they were abandoned [6]. Radiocarbon dating indicates that these soils were formed between 7000 and 500 cal years B.P. and are of pre-Columbian origin [7]. A hectare of meter-deep Terra Preta can contain 250 tons of carbon as opposed to 100 tons in unimproved soil [6]. Figure 1. Terra Preta do Indio in Brazil: (a) South America chorography; (b) Map of the Terra Preta sites; (c) Patterns of Terra Petra sites near Belterra (modified by Gerhard Bechtold [8]). (b) (a) (c) Sustainability 2014, 6 1331 Due to the accumulation of charred biomass and other organic residues, Terra Preta subsequently formed giving it a deep, distinctly dark and highly fertile soil layer in order to be productive without using fertilizers. From evidence of excavations and laboratory results, it was concluded that this culture had a superior sanitation and bio-waste system. This is due to the source separation of fecal matter, urine and clever additives (particularly charcoal dust) as well as treatment steps for the solids resulting in high yielding gardening. Additives included ground charcoal dust while the treatment and smell prevention started with anaerobic lactic-acid fermentation followed by vermicomposting. According to Brewer and Brown (2012) [9], from Orellana’s time until the middle of the nineteenth century, explorers passing through the central Amazon region did not make reference to the dark soils or the soil management practices of the natives in their writings. In the 1870s, several English-speaking geologists began making comments about fertile dark soils on sites of previous native villages while the first to record the term Terra Preta or dark soil were Briton C. Barrington Brown and William Lidstone. Figure 2a,b showed the network of roads connecting villages in the virgin forest and a graphical reconstruction of an indigenous Amazonian village, respectively. In 1879, Charles Hartt and Herbert Smith referred to dark soil areas as “kitchen middens” due to the amount of pottery found and the assumption that the fertility was caused by high organic residue deposition. Figure 2c shows sample soil profiles of Terra Preta soils and a typical jungle oxisol soil. Dark soil layers can be up to several meters thick, and cover patches from a few square meters to several square kilometers in size. Figure 2. Terra Preta do Indio in Brazil: (a) Networks of roads connect villages in the virgin forest [10]; (b) Graphic reconstruction of an indigenous Amazonian village; (c) In the left a nutrient-poor oxisol while in the right an oxisol transformed into fertile Terra Preta [11]. (a) (b) (c) Sustainability 2014, 6 1332 In 1903, Friedlich Katzer, in his book on Amazon geology (published in Leipzig, Germany), was the first to report extensive analytical data based on his fieldwork in the lower Amazon, south of Santarém. Katzer described the Amazonian dark soils as containing decomposed organic matter, mineral residues and charred plant material. Nearly a century ahead of his time, Katzer concluded that the high organic matter content of the dark earths showed that the soils were different from the surrounding jungle soils, but at the same time, they were made by human activity. Among the theories was that: (1) Terra Preta came from volcanic ash; (2) the fertile sites
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