Wastewater purification with UV lamps: Dr Terry Mabbett presents the facts about a water purification system that is rapidly gaining popularity both in Africa and overseas.(Water Supply)

WATER COVERS MOST of the planet, but fresh water is not an infinite resource and therefore needs to be re-cycled. Wastewater is invariably contaminated with physical and organic matter and chemicals which restrict the extent to which it can be re-used and the type of application, eg irrigation, cooling towers and groundwater re-charge. But biological contamination, and especially with potential disease-causing microbes like coliform bacteria, places the broadest and most stringent limits on wastewater re-use. Chemicals such as chlorine at established doses and concentrations can be ...