Glossary of Water and Wastewater Terms

A B C D E F G H I J K L M N O P Q R S T U V W Y Z Symbols and Numbers

5 random terms from our glossary

Volatile (VOL-uh-tull)

  1. A volatile substance is one that is capable of being evaporated or changed to a vapor at relatively low temperatures. Volatile substances can be partially removed from water or wastewater by the air stripping process.
  2. In terms of solids analysis, volatile refers to materials lost (including most organic matter) upon ignition in a muffle furnace for 60 minutes at 550°C (1,022°F). Natural volatile materials are chemical substances usually of animal or plant origin. Manufactured or synthetic volatile materials, such as plastics, ether, acetone, and carbon tetrachloride, are highly volatile and not of plant or animal origin. Also see NONVOLATILE MATTER.


  1. A substance that tends to lose a proton.
  2. A substance that dissolves in water and releases hydrogen ions.
  3. A substance containing hydrogen ion that may be replaced by metals to form salts.
  4. A substance that is corrosive.


The direction against the flow of water; or, toward or in the higher part of a sewer or collection system.

Disinfection (dis-in-FECT-shun)

The process designed to kill or inactivate most microorganisms in water or wastewater, including essentially all pathogenic (disease-causing) bacteria. There are several ways to disinfect, with chlorination being the most frequently used in water and wastewater treatment plants. Compare with STERILIZATION.

Information Collection Rule (ICR)

The Information Collection Rule (ICR) was promulgated on May 14, 1996 and approved by the Director of the Federal Register on June 18, 1996. It was to remain effective until December 31, 2000. The rule specified requirements for monitoring microbial contaminants and disinfection by-products (DBPs) by large public water systems (PWSs). It required large PWSs to conduct either bench- or pilot-scale testing of advanced treatment techniques. The data reported under the ICR were used by EPA to learn more about the occurrence of microbial contamination and disinfection by-products, the health risks posed, appropriate analytical methods, and effective forms of treatment. The ICR data form the scientific basis for EPA's development of the Enhanced Surface Water Treatment Rule and the Disinfectants and Disinfection By-Products (D/DBP) Rule.