Water Conservation—Whole Effluent Toxicity Paradox

Abstract

Total dissolved solids (TDS) management in water has become an increasingly important topic as competition for water supply sources and the intensity of use both increase. Regulatory failure of National Pollutant Discharge Elimination System (NPDES) whole effluent toxicity (WET) tests is one of several potential factors in managing TDS concentrations in effluent. Consequently, WET tests have become a de facto concentration standard that sets the limit for the intensity of water use and the amount of water conservation feasibly obtained for a facility. Conflicting regulations dealing with the application of mixing zones and antidegradation policies can prevent water conservation and actually result in the unintended consequence of causing more water use. The impact of TDS on NPDES-required WET tests, conflicting regulations dealing with the application of mixing zones that are counter-productive to water conservation, alternative practices currently being used, and other means of rectifying this paradox are discussed.