N.J. Admin. Code § 7:14A-9.7

Current through Register Vol. 56, No. 23, December 2, 2024

Section 7:14A-9.7 - Leak detection monitoring program

(a) Leak detection monitoring is required at sanitary landfills at all ground water monitoring wells installed as part of a ground water monitoring system established pursuant to 7:14A-9.3(a)1 and 2. At a minimum, a detection monitoring program shall include the monitoring for the constituents listed in Appendix A to this subchapter, incorporated herein by reference.

1. The Department shall remove any of the Appendix A monitoring parameters for a sanitary landfill if it can be shown that the removed constituents are not reasonably expected to be in or derived from the waste contained in the sanitary landfill unit.

2. The Department will establish an alternative list of inorganic indicator parameters for a sanitary landfill, in lieu of some or all of the heavy metals (constituents 1 through 15 in Appendix A to this subchapter), if the alternative parameters provide a reliable indication of inorganic releases from the sanitary landfill to the ground water. In determining alternative parameters, the Department shall consider the following factors:

i. The types, quantities, and concentrations of constituents in wastes managed at the sanitary landfill;

ii. The mobility, stability, and persistence of waste constituents or their reaction products in the unsaturated zone beneath the sanitary landfill;

iii. The detectability of indicator parameters, waste constituents and reaction products in the ground water; and

iv. The concentration or values and coefficients of variation of monitoring parameters or constituents in the ground water background.

(b) The monitoring frequency for all constituents listed in Appendix A to this subchapter, or in the alternative list approved in accordance with (a)2 above, shall be at least semiannual during the active life of the facility (including closure) and the post closure period. A minimum of four independent samples from each well (background and downgradient) shall be collected and analyzed for the Appendix A constituents, or the alternative list approved in accordance with (a)2 above during the first semiannual sampling event. At least one sample from each well (background and downgradient) shall be collected and analyzed during subsequent semiannual sampling events. The Department will specify an appropriate alternative frequency for repeated sampling and analysis for Appendix A constituents, or the alternative list approved in accordance with (a)2 above during the active life (including closure) and the post closure care period. The alternative frequency during the active life (including closure) shall be no less than annual. The alternative frequency shall be based on consideration of the following factors:

1. The lithology of the aquifer and unsaturated zone;

2. The hydraulic conductivity of the aquifer and unsaturated zone;

3. The ground water flow rates;

4. The minimum distance between upgradient edge of the sanitary landfill and downgradient monitoring well screen (minimum distance of travel), and

5. The resource value of the aquifer.

(c) If the owner or operator of a sanitary landfill determines, pursuant to 7:14A-9.5(g), that there is a statistically significant increase over background for one or more of the constituents listed in Appendix A-Part A to this subchapter or in the alternative list approved in accordance with (a)2 above, at any monitoring well at the boundary specified under 7:14A-9.3(a)2, the owner or operator shall:

1. Within 14 days of this finding, place a notice in the records maintained by the facility indicating which constituents have shown statistically significant changes from background levels, and notify the Department that this notice was placed in the operating record; and

2. Establish an assessment monitoring program meeting the requirements of 7:14A-9.8 within 90 days except as provided at (d) below.

(d) The owner or operator may demonstrate that a source other than a sanitary landfill caused the contamination or that the statistically significant increase resulted from error in sampling, analysis, statistical evaluation, or natural variation in ground water quality. A report documenting this demonstration shall be certified by a qualified ground water scientist or approved by the Department and be placed in the records maintained by the facility. If a successful demonstration is made and documented the owner or operator may continue detection monitoring as specified in this section. If, after 90 days, a successful demonstration is not made, the owner or operator shall initiate an assessment monitoring program as required in 7:14A-9.8.

N.J. Admin. Code § 7:14A-9.7