(a) Wastewater systems utilizing advanced pretreatment with a DDF greater than 1,500 gpd and less than or equal to 3,000 gpd may utilize the system siting and sizing in this Rule.
(b) The LTAR shall be based on the effluent standard and dispersal field type proposed in accordance with the following:
(1) The LTAR may be increased by the following factors when compared to the rate assigned by the authorized agent for a new system using DSE:
(A) up to 2.0 for TS-I or TS-II effluent standards; or
(B) up to 2.5 for TS-II effluent standards when there is a minimum of 48 inches of Group I soils from the naturally occurring soil surface and a minimum of 30 inches to a SWC below the naturally occurring soil surface.
(2) The LTAR for an aerobic drip system shall be determined in accordance with Rule .1204 of this Section.
(c) When the LTAR for a system is proposed to be increased in accordance with Paragraph (b) of this Rule, the following conditions shall be met:
(1) a special site evaluation required in accordance with Rule .0510 of this Subchapter shall be submitted and approved;
(2) pressure dispersal shall be utilized;
(3) space shall be available for an equivalently sized dispersal field repair area; and
(4) 25-foot setback shall be maintained to all property lines unless a site-specific nitrogen migration analysis for a TS-I system indicates that the nitrate-nitrogen concentration at the property line will not exceed 10 mg/L or a TS-II system is used.
(d) Trench dispersal products approved for a specific dispersal field reduction in area or trench length when receiving DSE in accordance with this Subchapter or a PIA Approval shall not be reduced by more than 50 percent as a result of increased LTAR in accordance with this Rule.
(e) The DDF shall not be increased by the addition of advanced pretreatment to an existing wastewater system.
(f) Wastewater systems utilizing advanced pretreatment with a DDF greater than 3,000 gpd may propose LTAR adjustments in accordance with Paragraphs (a) through (c) of this Rule. The Department shall review and approve the proposed LTAR adjustments in accordance with Rule .0302(e) of this Subchapter. Documentation shall also be provided that the proposed system meets the requirements of Rule .0510(e) of this Subchapter.
History Note: Authority G.S. 130A-334; 130A-335; 130A-342; 130A-343;
Eff. January 1, 2024.