ACUTE: A stimulus severe enough to rapidly induce an effect; in aquatic toxicity tests, an effect observed in 96 hours or less is typically considered acute.

ANTIDEGRADATION: Policies that ensure protection of water quality for a particular water body where the water quality exceeds levels necessary to protect fish and wildlife propagation and recreation on and in the water.

BIOASSAY: A test used to evaluate the relative potency of a chemical or a mixture of chemicals by comparing its effect on a living organism with the effect of a standard preparation on the same type of organism.

BIOSOLIDS: Sewage sludge that is used or disposed through land application, surface disposal, incineration, or disposal in a municipal solid waste landfill.

GRAB SAMPLE: A sample that is taken from a wastestream on a one-time basis without consideration of the flowrate of the wastestream and without consideration of time.

INDIRECT DISCHARGE: The introduction of pollutants into a municipal sewage treatment system from any nondomestic source (i.e., any industrial or commercial facility) regulated under the U.S. EPA’s Clean Water Act.

MIXING ZONE: A mixing zone is an allocated impact zone where water quality criteria can be exceeded as long as acutely toxic conditions are prevented.

NEW DISCHARGER: Any building, structure, facility, or installation: a. From which there is or may be a discharge of pollutants; b. That did not commence the discharge of pollutants at that particular site prior to August 13, 1979; c. Which is not a new source; and d. Which has never received a finally effective permit for discharges at that site.

PRETREATMENT: The reduction of the amount of pollutants, the elimination of pollutants, or the alteration of the nature of pollutant properties in wastewater prior to or in lieu of discharging pollutants into a public treatment works.

PRIMARY TREATMENT: The practice of removing some portion of the suspended solids and organic matter in a wastewater through sedimentation.

SANITARY SEWER: A pipe or conduit (sewer) intended to carry wastewater or water-borne wastes from homes, businesses, and industries to the POTW.

The terms and definitions for this issue’s Word Search were abstracted from a glossary on wastewater management produced by the U.S. Environmental Protection Agency. To view the glossary in its entirety, click here.