A simplified procedure for setting effluent quality standards

Abstract

The discharge of untreated effluents affects the quality of receiving water bodies and impairs their potential beneficial uses; to prevent this from happening, effluent quality standards (EQS) must be set. The conventional procedure for establishing EQS requires extensive knowledge of the receiving body characteristics. When there is an evident need for setting EQS, but all the information needed is not available (a situation probably common to many regions around the world), the need arises for a simplified procedure, such as the one herein proposed. The procedure is based on four tenets: 1) the classification of major water quality parameters into four classes: basic parameters, conservative contaminants, toxic contaminants and pathogens; 2) various sets of maximum permissible contaminant concentration (MPCC), for each class of contaminants; 3) two comprehensive classifications: one of effluent discharges according to their origin, and another of receiving waters based on their intended use and general characteristics; and 4) a two-dimensional matrix for different classes of effluent discharges and receiving bodies; four indices are proposed for each cell of the matrix, specifying MPCC for each class of parameters.