Экскременттерді ауыл шаруашылығында қауіпсіз пайдалану арқылы санитарияны жақсарту тәсілдері

Approach to sanitation provision which aims to safely reuse excreta in agriculture

Ecological sanitation, commonly abbreviated as ecosan (also spelled eco san or EcoSan), is an approach to sanitation provision which aims to safely reuse excreta in agriculture. Prior to 2012, ecosan has often been associated with urine diversion and in particular with urine diverting dry toilets (UDDTs), a type of dry toilet. For this reason, the term "ecosan toilet" is widely used when people mean a UDDT. However, the ecosan concept should not be limited to one particular type of toilet. Also, UDDTs can be used without having any reuse activities in which case they are not in line with the ecosan concept (an example being the 80,000 UDDTs implemented by eThekwini Municipality near Durban, South Africa).

The term "ecosan" was first used in 1995 and the first project started in 1996 in Ethiopia, by an NGO called Sudea. A trio, Dr Torsten Modig, Umeå University, Almaz Terrefe, teamleader, and Gunder Edström, hygiene expert, chose an area in a dense urban area as a starting point. They used urine diverting dry toilets (UDDTs) coupled with reuse activities. In the ecosan concept, human excreta and wastewater is regarded as a potential resource – which is why it has also been called "resource oriented sanitation". The term "productive sanitation" has also been in use since about 2006.

The definition of ecosan is focusing on the health, environment and resource aspect of sustainable sanitation. Thus ecosan is not, per se, sustainable sanitation, but ecosan systems can be implemented in a sustainable way and have a strong potential for sustainable sanitation, if technical, institutional, social and economical aspects are cared for appropriately. Ecosan systems can be "unsustainable" for example if there is too little user acceptance or if the costs of the system are too high for a given target group of users, making the system financially unsustainable in the longer term.

The main objectives of ecological sanitation are to reduce the health risks related to sanitation, contaminated water and waste; to prevent groundwater pollution and surface water pollution; and to reuse nutrients or energy contained within wastes.

The statement in the definition of ecosan to "safely recycle" includes hygienic, microbial and chemical aspects. Thus, the recycled human excreta product, in solid or liquid form, shall be of high quality both concerning pathogens and all kind of hazardous chemical components. The statement "use of non renewable resources is minimized" means that the gain in resources by recycling shall be larger than the cost of resources by recycling. Ecosan is based on an overall concept of material flows as part of an ecologically and economically sustainable wastewater management system tailored to the needs of the users and to the respective local conditions. It does not favor a specific sanitation technology, but is rather a certain philosophy in handling substances that have so far been seen simply as wastewater and water carried waste for disposal. Disease reduction was meant to be achieved not only by reducing infections transmitted via the fecal–oral route but also by reducing malnutrition in children. This link between WASH, nutrition, a disease called environmental enteropathy (or tropical enteropathy) as well as stunted growth of children has risen to the top of the agenda of the WASH sector since about 2013. Agricultural trials around the world have shown measurable benefits of using treated excreta in agriculture as a fertilizer and soil conditioner. This applies in particular to the use of urine. Reuse trials in Zimbabwe showed positive results for using urine on green, leafy plants such as spinach or maize as well as fruit trees. Another study in Finland indicated that the use of urine and the use of urine and wood ash "could produce 27% and 10% more red beet root biomass". Urine has been proven in many studies to be a valuable, relatively easy to handle fertilizer, containing nitrogen, phosphorus, potassium and important micro nutrients.

Another aspect that ecosan systems are trying to address is the possible upcoming shortage of phosphorus. Phosphorus has an important role for plant growth, and therefore in fertilizer production, but is a limited mineral resource. The situation is similar for potassium. Known mineral phosphate rock reserves are becoming scarce and increasingly costly to extract – this is also called the "peak phosphorus" crisis. One review of global phosphate supply suggested that if collected, phosphate in urine could supply 22% of the total demand.

Benefits of ecosan systems include: (the Arborloo, the Skyloo and the Fossa alterna). Peter Morgan is renowned as one of the leading creators and proponents of ecological sanitation solutions, which enable the safe reuse of human excreta to enhance soil quality and crop production. His ecosan type toilets are now in use in countries across the globe, centred on converting a sanitary problem into a productive resource. Technologies used in ecosan systems often but not always include elements of source separation, i. e. keeping different waste streams separate, as this can make treatment and safe reuse easier. The most common technology used in ecosan systems is the urine diverting dry toilet, but ecosan systems can also use other technologies, such as vacuum toilets coupled with biogas plants, constructed wetlands, composting toilets and so forth. Examples of ecosan projects worldwide can be found in a list published by GIZ in 2012, as well as in those case studies published by the Sustainable Sanitation Alliance that are focused on reuse activities.

The recovery and use of urine and feces in "dry sanitation systems", i. e. without sewers or without mixing substantial amounts of water with the excreta, has been practiced by almost all cultures. The reuse was not limited to agricultural production. The Romans, for example, were aware of the bleaching attribute of the ammonia within urine and used it to whiten clothing. The value of "night soil" as a fertilizer was recognized with well developed systems in place to enable the collection of excreta from cities and its transportation to fields. The Chinese were aware of the benefits of using excreta in crop production more than 2500 years ago, enabling them to sustain more people at a higher density than any other system of agriculture. In Peru, the Incas had a high regard for excreta as a fertilizer, which was stored, dried and pulverized to be utilized when planting maize. In the Middle Ages, the use of excreta and greywater in agricultural production was the norm. European cities were rapidly urbanizing and sanitation was becoming an increasingly serious problem, whilst at the same time the cities themselves were becoming an increasingly important source of agricultural nutrients. The practice of directly using the nutrients in excreta and wastewater for agriculture therefore continued in Europe into the middle of the 19th century. Farmers, recognizing the value of excreta, were eager to get these fertilizers to increase production and urban sanitation benefited. This practice was also called gong farmer in England but carried many health risks for those involved with transporting the excreta and fecal sludge. Besides direct use, excreta was also processed to produce pure chemicals. Using nitraries and nitre beds, one extract the nitrogen within as potassium nitrate (KNO3), a key ingredient in gunpowder. KNO3 was also responsible for the discovery of nitric acid in the 17th century. Traditional forms of sanitation and excreta reuse have continued in various parts of the world for centuries and were still common practice at the advent of the Industrial Revolution. Even as the world became increasingly more urbanised, the nutrients in excreta collected from urban sanitation systems without mixing with water were still used in many societies as a resource to maintain soil fertility, despite rising population densities. A publication by Sida called "Ecological sanitation" in 1998 compiled the knowledge generated to date about ecosan in a popular book which was published as a second edition in 2004. The book has also been translated into Chinese, French and Spanish. The German government enterprise GIZ also had a large "ecosan program" from 2001 to 2012. Whilst the term "ecosan" was preferred in the initial stages of this program, it was from 2007 onwards more and more replaced by the broader term "sustainable sanitation". In fact, the Sustainable Sanitation Alliance was founded in 2007 in an attempt to broaden the ecosan concept and to bring together various actors under one umbrella. Research into how to make reuse of urine and feces safe in agriculture was carried out by Swedish researchers, for example Hakan Jönsson and his team, whose publication on "Guidelines on the Use of Urine and feces in Crop Production" was a milestone which was later incorporated into the WHO "Guidelines on Safe Reuse of Wastewater, Excreta and Greywater" from 2006. The multiple barrier concept to reuse, which is the key cornerstone of this publication, has led to a clear understanding on how excreta reuse can be done safely.

During the 1990s, when the term ecosan was something new, discussions were heated and confrontational. Supporters of ecosan claimed the corner on containment, treatment and reuse. The proponents of conventional sanitation systems on the other side defended pit latrines and waterborne sewage systems. Ecosan supporters criticized conventional sanitation for contaminating waterways with nutrients and pathogens. Since about 2007, the two opposing sides have slowly found ways of dealing with each other, and the formation of the Sustainable Sanitation Alliance in that year has further helped to provide a space for all sanitation actors to meet and push into the same direction of sustainable sanitation.

Sweden is the leader in Europe to put ecosan into practice at a larger scale. For example, Tanum Municipality in Sweden has introduced urine separation toilets due to their very rocky and challenging terrain initially, and later also to recover phosphorus. Sweden has also made it possible in 2013 to certify safe and sanitized blackwater (urine and human excreta) from blackwater systems and for further use as a recognized fertilizer. Such blackwater systems could be vacuum toilets or septic tanks. The criteria for the certification have been developed by the Swedish Institute for Agricultural and Environmental Engineering and may pave the way for farmers to use human waste for agricultural production. The Federation of Swedish Farmers have been active in this development. Furthermore, the Swedish EPA in their last proposal in 2014 has downgraded the hygiene risk associated with urine. Stockholm Environment Institute (SEI) ran a large worldwide ecosan research programme called "Ecosanres" from 2001 to 2011. One of the "dry ecosan" pilot projects (i. e. with using dry toilets) of this programme was a large scale implementation of UDDTs in multi story buildings together with other technologies to allow resource recovery from excreta. This project was called the Erdos Eco Town Project in a town called Erdos in the Inner Mongolia Autonomous Region of China. It was a collaboration between the Dongsheng District government in Erdos and the Stockholm Environment Institute and aimed to save water and provide sanitation services in this drought stricken and rapidly urbanizing area of northern China. For a variety of technical, social and institutional reasons, the UDDTs were removed after only a few years and the project failed to deliver in the area of nutrient recovery. This project is now well documented and has raised more awareness of the challenges and disadvantages of "urban ecosan". The Rich Earth Institute in Brattleboro, Vermont, US, is an NGO dedicated to reclaiming human urine as fertilizer. They have established the only community scale urine nutrient reclamation program in the United States and are researching and developing treatment technologies to optimize the use of urine as fertilizer. SOIL in Haiti built what they call "ecosan toilets" (UDDTs) as part of the emergency relief effort following the 2010 Haiti earthquake. More than 20,000 Haitians are currently using SOIL ecological sanitation toilets and SOIL has produced over 400,000 liters of compost as a result. The compost is used for agricultural and reforestation projects. SOIL's composting process is effective in inactivating Ascaris eggs – an indicator for helminth eggs in general – in the excreta collected from the dry toilets within 16 weeks. The composting and monitoring methods used by SOIL in Haiti may serve as an example for other international settings. The NGO CREPA which was operating in the French speaking West Africa region (now called WSA – Water and Sanitation in Africa) was very active in ecosan promotion from 2002 to 2010 with a strong focus on UDDTs coupled with reuse in agriculture, especially in Burkina Faso.