15A NCAC 02B .0229. TAR-PAMLICO RIVER BASIN - NUTRIENT SENSITIVE WATERS MANAGEMENT STRATEGY: NUTRIENT OFFSET PAYMENTS FOR NON-TAR-PAMLICO BASIN ASSOCIA­TION MEMBERS

(a)  All waters of the Tar-Pamlico River Basin have been supplementally classified nutrient sensitive waters (NSW) pursuant to 15A NCAC 2B .0223.  The following procedures are to be implemented in accordance with 15A NCAC 2B .0223 in all waters of the Tar-Pamlico River Basin for those wastewater dischargers who are not members of the Tar-Pamlico Basin Association;

(b)  Existing wastewater dischargers expanding to greater than 0.5 million gallons per day (MGD), who are not members of the Tar-Pamlico Basin Association, shall be required to offset their additional nutrient loads by funding nonpoint source control programs approved by the Division of Water Quality prior to the issuance of their NPDES permit and at each renewal.  Nitrogen and phosphorus loads shall be offset at the rate of 110 percent of the cost to implement BMPs designed to reduce that same load created by expanding the discharge above 0.5 MGD.  Equations for calculating the offset costs are:

(1)           For an existing facility with permitted flow of less than or equal to 0.5 MGD as of December 8, 1994 expanding to greater than 0.5 MGD who is not a member of the Tar-Pamlico Basin Association:

Payment=((PF_e x (TN+TP) x 1384)-(0.5 x (TN+TP) x 1384)) x (BMP_c x 1.1) where:

Payment = the nutrient offset payment ($);

PF_e = Permitted Flow including expansion (MGD);

TN = 6 mg/l total nitrogen for domestic discharges or BAT for industrial discharges;

TP = 1 mg/l total phosphorus for domestic discharges or BAT for industrial discharges;

1384 = conversion factor;

0.5 = the permitted flow (MGD) above which payment for additional nutrient loading is required;

BMP_c = Best Management Practice cost-effectiveness rate in $/kg as set in 15A NCAC 2B .0237 of this Section;

1.1 = 110 percent of the cost for the nonpoint source controls.

(2)           For an expanding facility with a permitted flow of greater than or equal to 0.5 MGD as of December 8, 1994 who is not a member of the Tar-Pamlico Basin Association:

Payment=((PF_e x (TN+TP) x 1384)-(PF x (TN+TP) x 1384)) x (BMP_c x 1.1) where:

Payment = the nutrient offset payment ($);

PF_e = Permitted Flow including expansion (MGD);

PF = Permitted Flow as of December 8, 1994 (MGD);

TN = 6 mg/l total nitrogen for domestic discharges or BAT for industrial discharges;

TP = 1 mg/l total phosphorus for domestic discharges or BAT for industrial discharges;

1384 = conversion factor;

BMP_c = Best Management Practice cost-effectiveness rate in $/kg as set in 15A NCAC 2B .0237 of this Section;

1.1 = 110 percent of the cost for the nonpoint source controls.

(c)  New wastewater dischargers with permitted flows greater than or equal to 0.05 MGD, who are not members of the Tar-Pamlico Basin Association, shall be required to offset their nutrient loads by funding nonpoint source control programs approved by the Division of Water Quality prior to the issuance of their NPDES permit and at each renewal.  Nitrogen and phosphorus loads shall be offset at the rate of 110 percent of the cost to implement BMPs designed to reduce that same loading created by the new discharge above 0.05 MGD.  The equation for calculating the offset costs is:

Payment = PF x (TN+TP) x 1384 x (BMP_c x 1.1) where:

Payment = the nutrient offset payment ($);

PF = Permitted Flow (MGD);

TN = 6 mg/l total nitrogen for domestic discharges or BAT for industrial discharges;

TP = 1 mg/l total phosphorus for domestic discharges or BAT for industrial discharges;

1384 = conversion factor;

BMP_c = Best Management Practice cost-effectiveness rate in $/kg as set in 15A NCAC 2B .0237 of this Section;

1.1 = 110 percent of the cost for the nonpoint source controls.

(d)  Existing wastewater dischargers expanding to greater than 0.5 MGD, who are not members of the Tar-Pamlico Basin Association, may petition the Commission or its designee for an exemption from Paragraph (b) of this Rule upon meeting all of the following conditions:

(1)           For industrial facilities:

(A)          The facility has reduced its annual average TN loading by 30 percent from its annual average 1991 TN loading or nitrogen is not part of the waste stream above background levels;

(B)          The facility has reduced its annual average TP loading by 30 percent from its annual average 1991 TP loading or phosphorus is not part of the waste stream above background levels;

(C)          The expansion does not result in annual average TN loading greater than 70 percent of the 1991 annual average TN load.  Permit limits may be established to insure that the 70 percent load is not exceeded;

(D)          The expansion does not result in annual average TP loading greater than 70 percent of the 1991 annual average TP load.  Permit limits may be established to insure that the 70 percent load is not exceeded;

(E)           To maintain its exemption from Paragraph (b) of this Rule, a facility must continue to meet the requirements of Subparagraph (d)(1) Parts (A) through (D) of this Rule.

(2)           For municipal facilities:

(A)          The facility has reduced its annual average TN loading by 30 percent from its annual average 1991 TN loading;

(B)          The facility has reduced its annual average TP loading by 30 percent from its annual average 1991 TP loading;

(C)          The expansion does not result in annual average TN loading greater than 70 percent of the 1991 annual average TN load.  Permit limits may be established to insure that the 70 percent load is not exceeded;

(D)          The expansion does not result in annual average TP loading greater than 70 percent of the 1991 annual average TP load.  Permit limits may be established to insure that the 70 percent load is not exceeded;

(E)           To maintain its exemption from Paragraph (b) of this Rule, a facility must continue to meet the requirements of Subparagraph (d)(2) Parts (A) through (D) of this Rule.

 

History Note:        Authority G.S. 143‑214.1;

Eff. April 1, 1997.