Water Purification for Drinking

Introduction

• The provision of clean drinking water is often severely limited in developing countries.
• After natural disasters potable water infrastructure is often damaged which also limits potable water supplies.
• A range of technologies are able to produce clean drinking water from contaminated water.
• In a low carbon and resource constrained future solar distillation is a tried and proven way of producing clean drinking water for commmunities.
• Distillation systems are also useful in treating wastewater because they can evaporate all water leaving behind a salt for waste disposal.

F-cubed Technology

• F-cubed is a local manufacturer of solar distillation systems.
• Solar distillation panels are approx 1.2m x 3m
• Each panel can produce up to 20L of potable water per day.
• A 25-50W solar PV panel is required to power a small water pump.
• The water pump is rated at 23 Watts and operates at 12 Volts.

Mechanism of Operation

• Dirty water is pumped to the top of the F-cubed panel. The pump uses a solar PV panel (no battery) to pump the water during the day when the sun is shining.
• The water is dispersed across a black felt mat.
• Water runs down the panel through the pores of the black felt mat mainly by the action of gravity.
• As the drity water travels down the panel it is heated by the sun and some of the water evaporates.
• Evaporated water rises and then condenses on a clear plastic film that covers the top of the F-cubed panel.
• Condensed water droplets roll down the inside of the clear plastic film and collect at the bottom of the panel. This water is very clean and pure due to the distillation process.
• The distilled water exits the F-cubed panel and is collected as clean water.
• Dirty water also exits the F-cubed panel. This is the water that has not evaporated. It is collected separately and can be pumped back into the F-cubed panel to be distilled again.

F-cubed Brochure from web site

Monitoring the Performance of the Solar Distillation Panel

• We need to develop some environmental sensors so we can monitor the performance of the solar distillation system.
• Some examples are provided:
  • Amount of clean water produced - use load cells (similar to a bathroom scale) to measure the mass of water produced [1]
  • Measuring the conductivity, temperature and pH of dirty and clean water - Distilled water will have very low conductivity. Conductivity is a measure of salts and other impurities in water [2]