Solar disinfection is a low-cost method of disinfecting water that can often be implemented with locally available materials .No complicated technical knowledge is required so that it can be well used by all kind of people even uneducated. One of the main advantages of this method is it has low impact on the environment .It does not require any fire-wood, or electricity ,and it is well suitable to country like India where solar flux is available almost throughout the year. By adopting this method by all the nationals for their requirements of water, the nation can solve both the energy crisis (by reducing the energy used for water purifications) and drinking water problem.
Distillation by solar energy at NTP will remove from water almost anything, even heavy metals, poisons, bacteria and viruses. But if it done under reduced pressure, as the process is carried out at lower temperature, the removal of such unwanted things will not be complete. A simple and very ingenious method of achieving desalination under reduced pressure is given below: