Appropriate Technology


Rain Water Harvesting

Water is our most precious natural resource and something that most of us take for granted. We are now increasingly becoming aware of the importance of water to our survival and its limited supply, especially in dry season.

The harvesting of rainwater simply involves the collection of water from surfaces on which rain falls, and subsequently storing this water for later use. Normally water is collected from the roofs of buildings and stored in rainwater tanks. The water collected can be considered to be precious.

The collection of rainwater from the roofs of buildings can easily take place. All that is necessary to capture this water is to direct the flow of rainwater from roof gutters to a rainwater storage tank. By doing this, water can be and used for various purposes. It is possible to replace all or at least a substantial portion of your collected fresh water requirements by the capture and storage of rainwater from your roof. Being largely self sufficient in water supply is possible for a vast majority of households and buildings.



Waste management is one of the major challenges for developing countries like Nepal, where the waste generated is haphazardly dumped, is causing pollution to both surface and ground water sources. Consumption of contaminated water can cause various water borne diseases such as diarrhea, dysentery, typhoid, etc. The cases of water borne diseases are increasing, resulting in deaths of many children less than 5 years of age. Nonetheless, different technologies such as drainage systems, water treatment systems, sanitary landfill has been developed in various phases of time addressing these environmental and human health issues. But implementation of these technologies developed in the western countries demand huge investment and highly skilled man power mostly unavailable to developing countries. Therefore, 3 R Principal (Reduce, Recycle and Reuse) on waste management has been the most effective tool, providing ample opportunities to re-use of the waste as resources. Similar to woes of water resources, Nepals’ agriculture sector is also in grim situation. The excessive and continuous use of the chemical fertilizers for the higher production is not only deteriorating the soil fertility but also posing harm to human health. Instead, the use of natural fertilizers could best serve the need for sustainable farming and improve human health. In this context the concept of ‘Ecological Sanitation (EcoSan)’ has emerged as a solution to tackle both of these problems.


Wastewater Treatment


Decentralized Wastewater Treatment System (DEWATS) can be described as a low maintenance treatment system, treating small volumes of wastewater for reuse or discharge within National Standards. DEWATS generally treats domestic wastewater originating from individual or groups of dwellings, businesses or institutions that are located in close proximity to each other and the DEWATS site. Unlike conventional wastewater treatment plants, DEWATS promotes technologies that use natural processes and are simples in operation and maintenance. In DEWATS, natural treatment processes are achieved through methods that make use of physical principles combined with biological activities of microorganisms. Bacteria colonies in the treatment devices are generated from microbial populations that occur naturally in the wastewater.


Drinking Water Treatment

SODIS (Solar Water Disinfection)

SODIS (Solar Water Disinfection) is a simple water treatment method relying on solar electromagnetic radiation and temperature to inactive pathogens. SODIS capitalizes on the UV-A radiation of the solar electromagnetic spectrum to a germicidal effect. Additionally, infrared radiation raises the water temperature which has a pasteurization effect. Research has shown that SODIS is more efficient in water containing high levels of oxygen. In order to achieve maximum saturation of the water with oxygen, the bottles are filled up to three quarters and shaken for about 20 seconds before they are filled completely to the brim.

Although water supply coverage has increased remarkably in Nepal, not much attention has been given to improve the water quality. Recurring outbreaks of water borne diseases and high numbers of patients being admitted to hospitals with water borne disease ailments indicates a need to public health status via improving water quality. Additionally, the low income community are more vulnerable to such diseases and the subsequent economic repercussions. Considering the above mentioned factoids, it is essential to promote simple, low cost and effective water treatment options.