Appropriate technologies find many applications in building and construction, agriculture, water and sanitation, energy generation and uses, transportation, health care, food preparation and storage, information and communication technologies, as well as finance.
Building and construction In order to increase the efficiency of city services (water provisioning, electricity provisioning, easy traffic flow, water drainage, decreased spread of disease with epidemics, etc.), the city itself must first be built correctly. In the developing world, many cities are expanding rapidly and new ones are being built. Urban planning is therefore important.
Adobe (including the variation called Super Adobe), Rammed earth, Compressed earth block, Animal products, Cob and/or other green building materials could be considered appropriate earth building technology for much of the developing world, as they make use of materials which are widely available locally and are thus relatively inexpensive.
The local context must be considered as, for example, mudbrick may not be durable in a high rainfall area (although a large roof overhang and cement stabilisation can be used to correct for this), and, if the materials are not readily available, the method may be inappropriate. Other forms of natural building may be considered appropriate technology, though in many cases the emphasis is on sustainability and self-sufficiency rather than affordability or suitability. As such, many buildings are also built to function as autonomous buildings (e.g., earthships). One example of an organisation that applies appropriate earthbuilding techniques would be Builders Without Borders.
The building structure must also be considered. Cost-effectiveness is an important issue in projects based around appropriate technology, and one of the most efficient designs herein is the public housing approach. This approach lets everyone have their own condominium, yet incorporate communal spaces such as mess halls, latrines, and public showers.
In addition, to decrease costs of operation (heating, cooling, etc.) techniques as Earth sheltering and Trombe walls are often incorporated.
Organizations as Architecture for Humanity also follows principles consistent with appropriate technology, aiming to serve the needs of poor and disaster-affected people.
Natural ventilation can be created by providing vents in the upper level of a building to allow warm air to rise by convection and escape to the outside, while cooler air is drawn in through vents at the lower level. Electrical powered fans (e.g., ceiling fans) allow efficient cooling, at a far lower electricity consumption as airconditioning systems. A solar chimney often referred to as thermal chimney improves this natural ventilation by using convection of air heated by passive solar energy. To further maximize the cooling effect, the incoming air may be led through underground ducts before it is allowed to enter the building. A windcatcher (Badgir; بادگیر) is a traditional Persian architectural device used for many centuries to create natural ventilation in buildings. It is not known who first invented the windcatcher, but it still can be seen in many countries today. Windcatchers come in various designs, such as the uni-directional, bi-directional, and multi-directional. A passive down-draft cooltower may be used in a hot, arid climate to provide a sustainable way to provide air conditioning. Water is allowed to evaporate at the top of a tower, either by using evaporative cooling pads or by spraying water. Evaporation cools the incoming air, causing a downdraft of cool air that will bring down the temperature inside the building.
Agriculture Appropriate technology has been applied extensively to improve agricultural production in developing countries. In the United States, the National Center for Appropriate Technology operates ATTRA (attra.ncat.org), a national sustainable agriculture assistance program.
The focus of discussion and research regarding technology adoption is the small scale farm, because it accounts for the majority of the planet's agricultural output. The ethical question that emerges in the research is how much to focus on increasing the productivity of a nation's agricultural output and how much to address food insecurity in the population, including among farmers themselves. This issue of framing is significant because if countries are producing enough food for their populations, yet people are still not getting adequate amounts of food or proper nutrition, it is a problem of availability and distribution rather than production. It is possible for countries to have the agricultural capabilities to be completely self-supportive, but still have many food-insecure citizens. India is an example of this situation. The opposite can also be true; as of 2012, neither Hong Kong nor Singapore had the internal capability to sustainably feed their respective populations, yet they had much better rates of food-security than India. A problem can arise when research focuses solely on advancements in production, ignoring the problem of food-insecurity in these communities.
Food insecurity is more than just a matter of increasing farm production: it is also about farm household income, location, amount of debt, and level of education. Rural and impoverished communities are disproportionately and adversely affected by inequitable distribution of food and resources. Increasing food production and output will not make distributing food easier or more equitable. Confronting these more difficult issues is the future of the sector's discussions and actions.
Water and sanitation
Water
As of 2006, waterborne diseases are estimated to cause 1.8 million deaths each year while about 1.1 billion people lack proper drinking water."Safe Water System," US Centers for Disease Control and Prevention Fact Sheet, June 2006.
Water generally needs treatment before use, depending on the source and the intended use (with high standards required for drinking water). The quality of water from household connections and community water points in low-income countries is not reliably safe for direct human consumption. Water extracted directly from surface waters and open hand-dug shallow wells nearly always requires treatment.
Appropriate technology options in water treatment include both community-scale and household-scale point-of-use (POU) designs.
The most reliable way to kill microbial pathogenic agents is to heat water to a rolling boil.WHO's Guidelines for Drinking Water Quality Other techniques, such as varying forms of filtration, chemical disinfection, and exposure to ultraviolet radiation (including solar UV) have been demonstrated in an array of randomized control trials to significantly reduce levels of waterborne disease among users in low-income countries.
Over the past decade, an increasing number of field-based studies have been undertaken to determine the success of POU measures in reducing waterborne disease. The ability of POU options to reduce disease is a function of both their ability to remove microbial pathogens if properly applied and such social factors as ease of use and cultural appropriateness. Technologies may generate more (or less) health benefit than their lab-based microbial removal performance would suggest.
The current priority of the proponents of POU treatment is to reach large numbers of low-income households on a sustainable basis. Few POU measures have reached significant scale thus far, but efforts to promote and commercially distribute these products to the world's poor have only been under way for a few years.
On the other hand, small-scale water treatment is reaching increasing fractions of the population in low-income countries, particularly in South and Southeast Asia, in the form of water treatment kiosks (also known as water refill stations or packaged water producers). While quality control and quality assurance in such locations may be variable, sophisticated technology (such as multi-stage particle filtration, UV irradiation, ozonation, and membrane filtration) is applied with increasing frequency. Such microenterprises are able to vend water at extremely low prices, with increasing government regulation. Initial assessments of vended water quality are encouraging.
Whether applied at the household or community level, some examples of specific treatment processes include: Porous ceramic filtration, using either clay or diatomaceous earth, and oriented as either cylinder, pot, or disk, with gravity-fed or siphon-driven delivery systems. Silver is frequently added to provide antimicrobial enhancement Intermittently operated slow-sand filtration, also known as biosand filtration Chlorine disinfection, employing calcium hypochlorite powder, sodium hypochlorite solution, or sodium dichloroisocyanurate (NaDCC) tablets Chemical flocculation, using either commercially produced iron or aluminum salts or the crushed seeds of certain plants, such as Moringa oleifera. Recent work has shown even table salt (NaCl) is effective at removing high-activity clays for solar water disinfection. Irradiation with ultraviolet light, whether using electric-powered lamps or direct solar exposure such as with the SODIS method Mixed flocculation/disinfection using commercially produced powdered mixtures membrane filtration, employing ultrafiltration or reverse osmosis filter elements preceded by pretreatment
Some appropriate technology water supply measures include: Deep wells with submersible pumps in areas where the groundwater (aquifers) are located at depths >10 m. Shallow wells with lined walls and covers. Rainwater harvesting systems with an appropriate method of storage, especially in areas with significant dry seasons. Fog collection, which is suitable for areas which experience fog even when there is little rain. Air wells, a structure or device designed to promote the condensation of atmospheric moisture. Handpumps and treadle pumps are generally only an option in areas is located at a relatively shallow depth (e.g., 10 m). The Flexi-Pipe Pump is a notable exception to this (up to 25 meters). For deeper aquifers (<10 m), The Rope pump and submersible pumps placed inside a well can be used. Treadle pumps for household irrigation are now being distributed on a widespread basis in developing countries. The principle of Village Level Operation and Maintenance is important with handpumps, but may be difficult in application. Condensation bags and condensation pits can be an appropriate technology to get water, yet yields are low and are (for the amount of water obtained), labour-intensive. Still, it may be a cheap solution for certain desperate communities. The hippo water roller and Q-drum allow more water to be carried, with less effort and could thus be a good alternative for ethnic communities who do not wish to give up water gathering from remote locations, assuming low topographic relief. The roundabout playpump, developed and used in southern Africa, harnesses the energy of children at play to pump water.
Sanitation
Poor sanitation is a major issue for a large proportion of the human population, with about 2.5 billion people lacking even the most basic forms of sanitation and more than a billion people worldwide practising open defecation in 2015 according to the Joint Monitoring Programme for Water Supply and Sanitation of the United Nations.WHO and UNICEF Progress on Drinking-water and Sanitation: 2012 Update, WHO, Geneva and UNICEF, New York, page 2