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The application of Appropriate Technology

Water Treatment

Information about drinking filtering drinking water and coping with water hardness.

  • Articles:

    Small Community Water Supplies

    This book is a very good place to start learning about building a water supply. It covers all the things that you will need to know about sourcing water including rain water harvesting, spring, wells and surface water. It also has sections on water quality and treatment. This book is made available here as PDF […]

    Managing Water In The Home: Accelerating Health Gains From Improved Water Supply

    A WHO document from 2002 examining small scale water purification methods. A large fraction of the World’s population around 1.1 billion people – does not have access to improved sources of water. For many others, contamination of water during transport and in the household presents a significant health risk. For this segment of the world’s […]

    • Sections:

      Water Quality

      Articles about drinking water standards and how to ensure a safe water supply.


      WHO Guidelines For Drinking-water Quality, 4th Edition

      The primary purpose of the Guidelines for Drinking-water Quality is the protection of public health. Water is essential to sustain life, and a satisfactory (adequate, safe and accessible) supply must be available to all. Improving access to safe drinking-water can result in tangible benefits to health. Every effort should be made to achieve a drinking-water quality as safe as practicable. Safe drinking-water, as […]

      An Introduction To Water Hardness

      A document providing an introduction to the causes and treatment of hard water, including magnetic water softeners. Some Simple Chemistry When ionic substances dissolve in water they are split into their constituent ions. For example when NaCl (sodium chloride, common salt) dissolves in water it produces Na+ (the positive or cation) and Cl– (the negative or anion). […]

      Facilitating Community Water Supply

      This publication is about what it takes to ensure that when people open their tap they can safely drink the water, with information on water treatment, multi-stage filtration and slow-sand filtration. This publication tells you about these technologies, how they were developed and shared and what was learned in the process. It discusses technology transfer and […]

    • Water Filtration

      Documents about slow sand filtration and multi-stage filtration. Slow sand filtration can be use from a very small household scale right up to filtering the water supplies for whole cities. It allows water to pass slowly through a sand bed where the majority of the purifying process happens in a naturally occurring bio-layer in the first few millimetres of […]


      Surface Water Treatment By Roughing Filters

      Excellent manual on roughing filters by SANDEC, detailing water treatment alternatives applicable to rural water supplies and processes for solid matter separation. For further SANDEC publications, go here:http://www.eawag.ch. You can read the whole document as a PDF file (12.4 Mb)

      Horizontal Flow Roughing Filter

      Manual detailing how to estimate and design horizontal flow roughing filters. Among pre-treatment methods used before slow sandfilters (SSF), horizontal-flow roughing filters( HRF) have been found to be the most effective and appropriate for application in developing countries. This is because they are simple, require no mechanical parts, have low capital cost, can be operated […]

      An Introduction to Slow Sand Filtration

      The use of sand and gravel as filter media for water supplies can me split into three basic filter types: slow sand filters, rapid filters and roughing filters. Apart from desalination and reverse osmosis, slow sand filters are perhaps the most effective single treatment for purifying drinking water supplies. They are use on a large scale as part […]

      Slow Sand Filtration

      By L. HUISMAN and W.E. WOOD. A WHO document from 1974 outlining the action, construction, operation and maintenance of slow sand filters. This is the standard text on the subject. (PDF Files) Contents & Preface (13 KB) Chapter 1 – Introduction (41 KB) Chapter 2 – Filtration of water supplies (1.2 MB) Chapter 3 – Theory of biological […]

      Life Water Slow Sand Filter

      Plans, construction guide and operation instructions for Life Water’s slow sand filter, suitable for a town of 1 or 2 thousand people. Lifewater is a water charity based in the USA. This document is available as 3 PDF files: Design (1 Mb) Construction (720 Kb) Operation & Maintenance (436 Kb)

      Biosand Filters

      The biosand filter is a modified form of the traditional slow sand filter in such a way that the filters can be built on a smaller scale and can be operated intermittently. These modifications make the biosand filter suitable for household or small group use. The biosand filter can be produced locally anywhere in the […]

    • Solar Water Treatment

      This is a very simple method of killing pathogens in water using nothing more than a soft drink bottle and the sun.



      SODIS is a water treatment method which uses solar energy to improve the microbiological water quality. It is used at household level to treat small quantities of drinking water. The treatment process is a simple technology using solar radiation to inactivate and destroy pathogenic microorganisms present in the water. The treatment basically consists in filling […]

      Solar Water Distiller

      Solar Stills operate on the same principles that produce rainfall. The sun is allowed into and trapped in the Still. The high temperatures produced destroy all pathogens. The water evaporates, and in this process, only pure water vapor rises in the Still, only to condense on the glass. You can read the whole document as […]

    • Water Treatment Links

      Links to sites that have information about water treatment and water quality.