Point Source Wastewater Treatment Requirements

Unless more stringent limitations are necessary to meet the applicable requirements of Sections 200 through 300, or IDAHO ADMINISTRATIVE CODE IDAPA 58.01.02 Department of Environmental Quality Water Quality Standards Section 800 Page 180 unless specific exemptions are made pursuant to Subsection 080.02, wastewaters discharged into surface waters of the state must have the following characteristics: (3-31-22) 01. Temperature. The wastewater must not affect the receiving water outside the mixing zone so that: (3-31-22) a. The temperature of the receiving water or of downstream waters will interfere with designated beneficial uses. (3-31-22) b. Daily and seasonal temperature cycles characteristic of the water body are not maintained. (3-31-22) c. If the water is designated for warm water aquatic life, the induced variation is more than plus two (+2) degrees C. (7-1-26) d. If the water is designated for cold water aquatic life, seasonal cold water aquatic life, or salmonid spawning, the induced variation is more than plus one (+1) degree C. (7-1-26) e. If temperature criteria for the designated aquatic life use are exceeded in the receiving waters upstream of the discharge due to natural background conditions, then Subsections 401.01.c. and 401.01.d. do not apply and instead wastewater must not raise the receiving water temperatures by more than three tenths (0.3) degrees C above the natural background conditions. (7-1-26) 02. Turbidity. The wastewater must not increase the turbidity of the receiving water outside the mixing zone by: (3-31-22) a. More than five (5) NTU (Nephelometric Turbidity Units) over background turbidity, when background turbidity is fifty (50) NTU or less; or (3-31-22) b. More than ten percent (10%) increase in turbidity when background turbidity is more than fifty (50) NTU, not to exceed a maximum increase of twenty-five (25) NTU. (3-31-22) 402. -- 799. (RESERVED)