The document is intended to provide guidance to permittees, permit writers, and consultants on the general approach and procedures for conducting toxicity reduction evaluations (TREs) at municipal wastewater treatment plants. TREs are important tools for Publicly Owned Treatment Works (POTWs) to use to identify and reduce or eliminate toxicity in a wastewater discharge. The guidance describes the general approaches that have been successfully used in municipal TREs. Additions to this guidance include cosiderations in evaluating the current TIE procedures for acute and short-term chronic toxicity, updated methods for tracking sources of acute and chronic toxicity in POTW sewer collection systems, and addtional recent case studies on acute and chronic TREs using freshwater and estuarine/marine species. Information is also provided on sampling requirements, equipment and facilities, quality assurance/quality control, and health and safety.

"August 1999." "This document is an update of the TRE protocol that was published in 1989 [Toxicity reduction evaluation protocol for municipal wastewater treatment plants.]." "EPA 833-B-99/002."