Guideline for release of ammonia in wastewater effluents: long description

Long Description for Figure 1

Figure 1 - Threshold Acute Concentration for Ammonia versus pH

Figure #1 shows the relationship between the threshold acute concentration of Ammonia to Rainbow trout versus pH. Ammonia expressed as Nitrogen (mg/L) forms the Y axis of this figure, and pH forms the X axis. As the pH level increases in the effluent, the concentration at which ammonia becomes acutely lethal gradually decreases based on a logarithmic relationship. The maximum Ammonia level is approximately 185 mg/L at a pH of 7. The minimum Ammonia level is approximately 2 mg/L at a pH of 9.5+. This relationship has been determined from test results using Environment Canada's Rainbow trout Acute Lethality Test RM 9