Potable water - Filtration and Purification

A report by Peter H. Gleick estimates that if no action is taken to address unmet basic human needs for water, as many as 135 million people will die from water-related diseases by 2020.  Rainwater harvesting is viewed by many, as a partial solution to the problems posed by water scarcity: droughts and desertification, erosion from runoff, over-reliance on depleted aquifers, and the costs of new irrigation, diversion, and water treatment facilities.

 

Can rainwater be made safe to drink? Yes. How safe? As safe as your well or tap water. How do you make it safe for indoor use? By filtering and purifying it. Contaminants in water may include algae, air pollution, bird excrement, and leaves, sand, and dust. Local wells have dealt with these problems for decades. Installation of filtration and purification equipment can remove these contaminants at home as well.

Principles of Water Management for People and the Environment

Michael Acreman, Freshwater Management Adviser to the IUCN, Institute of Hydrology, United Kingdom

Water, the Environment, and Population

Water is the lifeblood of our planet. It is fundamental to the biochemistry of all living organisms. The planet's ecosystems are linked and maintained by water, and it drives plant growth, provides a permanent habitat for many species (such as 8,500 species of fish), and is a breeding ground or temporary home for others, including most of the worlds 4,200 species of amphibians and reptiles described so far. Water is also a universal solvent and provides the major pathway for the flow of sediment, nutrients and pollutants. Through erosion, transportation and deposition by rivers, glaciers, and icesheets, water shapes the landscape and through evaporation it drives the energy exchange between land and the atmosphere, thus controlling the Earth's climate.

Apart from a few minor chemical processes, water is neither created nor destroyed, it only moves from place to place and changes in quality. The total amount of water on Earth is 1.4 billion cubic kilometers (km3), but only around 41,000 km3 circulates through the hydrological cycle, the remaining being stored for long periods in the oceans, ice caps and aquifers. Furthermore, the renewal rate provided by rainfall varies around the world. In the Atacama desert in southern Peru it almost never rains, whilst 6,000 millimeters (mm) of rain per year is not uncommon in parts of New Zealand. In any one place rainfall also varies from year to year.