Oklahoma Administrative Code › Title 252 - Department of Environmental Quality › Chapter 628 - Indirect Potable Reuse for Surface Water Augmentation › Subchapter 3 - Benchmarks and Implementation for IPR Source Water Discharges › Section 252:628-3-7 - IPR benchmarks for nutrients, chlorophyll-a, and algal biomass

Current through Vol. 41, No. 20, July 1, 2024
(a)
Water
				quality standards.
IPR Source Water discharges shall not cause or
				contribute to an exceedance of narrative or numerical OWQS for nutrients,
				dissolved oxygen or chlorophyll-a. The evaluation of potential OWQS impacts
				shall be made using DEQ-approved effluent and receiving waterbody
				modeling.
(b)
Eutrophication.
IPR Source Water discharges shall not cause or
				contribute to excessive growth of algal biomass, periphyton, phytoplankton,
				cyanobacteria, or aquatic macrophyte communities, which impairs any existing or
				designated beneficial use.
(c)
Mixing zones.
No mixing zones or dilution factors shall be allowed
				for establishing effluent limitations for nitrate (as N) and nitrite (as N).
				Mixing zones or dilution factors shall be designated on a case-by-case basis
				for establishing effluent limitations for other nutrients, unless superseded by
				mixing zones or dilution factors established in OAC 252:740.
(d)
Total nitrogen.
Total
				nitrogen shall not exceed 8 milligrams per liter as a monthly average or 12
				milligrams per liter daily maximum. More stringent effluent limitations
				representing enhanced nutrient removal technologies for nitrogen may be
				established where DEQ-approved modeling demonstrates that the IPR Source Water
				discharge may cause or contribute to an increase in ambient receiving waterbody
				concentrations of nitrogen to levels that would violate paragraph (a) or (b) of
				this Section, or of nitrate (as N) to levels that would exceed 10 milligrams
				per liter.
(e)
Total
				phosphorus.
Total phosphorus shall not exceed 0.2 milligrams per liter
				monthly average or 0.3 milligrams per liter daily maximum. More stringent
				effluent limitations representing enhanced nutrient removal technologies for
				phosphorus may be established where DEQ-approved modeling demonstrates that the
				IPR Source Water discharge may cause or contribute to an increase in ambient
				receiving waterbody concentrations of phosphorus to levels that would violate
				paragraph (a) or (b) of this Section.
(f)
Chlorophyll-a.
The following
				requirements apply:
(1)
SWS-R
				Waterbodies.
IPR Source Water discharges shall not cause or contribute
				to an increase in ambient receiving waterbody concentrations to levels that
				would exceed the aggregate long-term average concentration of chlorophyll-a at
				a depth of 0.5 meters below the waterbody surface of 0.010 milligrams per
				liter. Effluent limitations for nutrients to ensure compliance with this
				criterion shall be developed based on DEQ-approved modeling of the discharge
				and receiving waterbody.
(2)
Non-SWS-R Waterbodies.
IPR Source Water discharges shall not cause
				or contribute to an exceedance of narrative or numerical water quality
				standards for nutrients or chlorophyll-a. Effluent limitations for nutrients to
				ensure compliance with these criteria shall be developed based on DEQ-approved
				modeling of the discharge and receiving water.