Clean Water

With explosive population and industry growth, the need for cost-effective water-purification and wastewater-treatment technologies has become more urgent than ever. Chemical-engineering principlesare used to remove harmful pollutants from both raw source water and contaminated wastewater.
Specifically, chemical engineers have developed cost-effective methods to
* Purify water fromsubsurface aquifers and surface sources, such as rivers and lakes, to produce potable drinking water;
* Produce purified water that meets the increasingly strict requirements for industrial use; and* Treat contaminated industrial and municipal wastewater and sewage to make them suitable either for discharge to public waterways or for reuse.

Treating water
Modern-day treatment of raw watersources or contaminated wastewater employs a wide array of physical, chemical, and biological techniques.
Chemical engineers refer to separating dangerous materials from good water as a treatmenttrain. At various stages in the multistage treatment process, unwanted constituents are separated using
* Vacuum or pressure filtration,
* Centrifugation,
* Membrane-based separation,* Distillation,
* Carbon-based and zeolite-based adsorption, and
* Advanced oxidation treatments.

Activated carbon is a highly adsorbent form of carbon that is produced whencharcoal is heated. Its extremely intricate internal-pore structure provides exceptionally high internal surface area: just 5 grams of activated carbon has the surface area of a football field. Activatedcarbon removes impurities via adsorption from both aqueous and gaseous waste.
Membranes allow materials of a certain size or smaller to pass through but block the passage of larger materials.Imaginative arrays of membrane materials in innovative physical configurations are used to separate unwanted solids and dissolved chemicals from tainted water. During operation, purified water diffuses...