Processes are available to remove more than 99 percent of the suspended solids and BOD5. Processes such as reverse osmosis and electrodialysis reduce dissolved solids. Ammonia stripping, denitrification, and phosphate precipitation can remove nutrients. If the wastewater is to be reused, disinfection by ozone treatment is considered the most reliable method other than breakpoint chlorination. Application of these and other advanced waste-treatment methods is likely to become widespread in the future in view of new efforts to conserve water through reuse.
Pure water is an odorless, tasteless liquid.
It has a bluish tint, which may be detected, however, only in layers of considerable depth. Supercooled water will freeze if it is disturbed, if the temperature is lowered further, or if an ice crystal or other particle is added to it. Its physical properties are used as standards to define the calorie and specific and latent heat and in the metric system for the original definition of the unit of mass, the gram. Capillarity, or capillary action, depends on the forces created by surface tension and by wetting of the sides of the tube. These elements are toxic, even in small amounts.