74 : 36 : 07 : 114 . Existing municipal solid waste landfill compliance with surface methane operational standards. The owner or operator of an existing municipal solid waste landfill that meets the requirements of subdivision 74:36:07:111 (4) must comply with the following procedures for demonstrating compliance with the surface methane operational standards:

1. (1) After installation and startup of the gas collection system, the owner or operator must monitor surface concentrations of methane along the entire perimeter of the collection area and along a pattern that traverses the landfill at no more than thirty-meter intervals or a site-specific established spacing for each collection area on a quarterly basis using an organic vapor analyzer, flame ionization detector, or other portable monitor meeting the specifications provided in § 74:36:07:115;
2. (2) The background concentration is determined by moving the probe inlet upwind and downwind outside the boundary of the landfill at a distance of at least thirty meters from the perimeter wells;
3. (3) Surface emission monitoring must be performed in accordance with 40 C.F.R. Part 60, Appendix A, Method 21, section 8.3.1 (July 1, 2024) except the probe inlet must be placed within five to ten centimeters of the ground. Monitoring must be performed during typical meteorological conditions;

4. (4) Any reading of five hundred parts per million or more above background at any location must be recorded as a monitored exceedance. As long as the following actions are taken, the exceedance is not a violation of the operational requirements of subdivision 74:36:07:111(4):

   1. (a) The location of each monitored exceedance is marked and the location and concentration are recorded. For location, the owner or operator shall determine the latitude and longitude coordinates using an instrument with an accuracy of at least four meters. The coordinates must be in decimal degrees with at least five decimal places;
   2. (b) Cover maintenance or adjustments to the vacuum of the adjacent wells to increase the gas collection in the vicinity of each exceedance are made and the location is re-monitored within ten calendar days of detecting the exceedance;
   3. (c) If the re-monitoring of the location shows a second exceedance, additional corrective action must be taken and the location must be monitored again within ten days of the second exceedance. If the re-monitoring shows a third exceedance for the same location, the action specified in subsection (e) must be taken, and no further monitoring of that location is required until the action specified in subsection (e) has been taken;
   4. (d) Any location that initially showed an exceedance but has a methane concentration less than five hundred parts per million methane above background at the ten-day re-monitoring specified in subsection (4)(b) or (c) must be re-monitored within one month after the initial exceedance. If the one-month re-monitoring shows a concentration less than five hundred parts per million above background, no further monitoring of that location is required until the next quarterly monitoring period. If the one-month re-monitoring shows an exceedance, the actions specified in subsection (c) or (e) must be taken; and
   5. (e) For any location where monitored methane concentration equals or exceeds five hundred parts per million above background three times within a quarterly period, a new well or other collection device must be installed within one hundred twenty calendar days of the initial exceedance. An alternative remedy to the exceedance, such as upgrading the blower, header pipes or control device, and a corresponding timeline for installation may be submitted to the secretary for approval; and
5. (5) The owner or operator must implement a program to monitor for cover integrity and implement cover repairs, as necessary, on a monthly basis.

Source: 46 SDR 64, effective November 25, 2019 ; 52 SDR 27, effective September 17, 2025 .

General Authority: SDCL 34A-1-6 , 34A-1-18 .

Law Implemented: SDCL 34A-1-18 .

Prior versions effective: 2019-11-25.