North Carolina Administrative Code › Title 15A - Environmental Quality › Chapter 13 - SOLID WASTE MANAGEMENT › Subchapter B - SOLID WASTE MANAGEMENT › Section .1600 - REQUIREMENTS FOR MUNICIPAL SOLID WASTE LANDFILL FACILITIES (MSWLFS) › Section 13B .1624 - CONSTRUCTION REQUIREMENTS FOR MSWLF FACILITIES

Current through Register Vol. 39, No. 2, July 15, 2024
(a) This
				  Rule shall establish the performance standards and criteria for designing and
				  constructing an MSWLF unit. Additional standards for the cap system are
				  described in Rule .1627 of this Section.
(b) MSWLF units shall comply with the
				  following design and construction criteria:
(1) Base liner system description. The base
				  liner system is constructed on the landfill subgrade and shall be designed to
				  contain, collect and remove leachate generated by the MSWLF unit. The
				  components of the liner system shall consist of the following.
(A) A Base Liner. The base liner shall
				  consist of one of the following designs. The design described in Subpart (i) of
				  this Part is the standard composite liner. If a landfill owner or operator
				  proposes to utilize one of the alternative composite liner designs described in
				  Subparts (ii) and (iii) of this Part the owner or operator shall demonstrate
				  through a model that the proposed design shall ensure that maximum contaminant
				  levels (MCL) promulgated under
				  40 CFR
				  141 shall not be exceeded in the uppermost
				  aquifer at the relevant point of compliance as established in Rule .1631(a)(2)
				  of this Section. For these two designs, the Division may waive the
				  site-specific modeling requirement if it can be demonstrated that a previous
				  site for which a model was approved had similar hydrogeologic characteristics,
				  climatic factors, and volume and physical and chemical leachate
				  characteristics. If an alternative liner design other than Subparts (ii) and
				  (iii) of this Part is proposed, the Division shall require site-specific,
				  two-phase modeling as described in Subpart (iv) of this Part.
(i) A composite liner utilizing a compacted
				  clay liner (CCL). The composite liner is one liner that consists of two
				  components; a geomembrane liner installed above and in direct and uniform
				  contact with a compacted clay liner with a minimum thickness of 24 inches (0.61
				  m) and a permeability of no more than 1.0 X 10-7
				  cm/sec. The composite liner shall be designed and constructed in accordance
				  with Subparagraphs (8) and (10) of this Paragraph.
(ii) A composite liner utilizing a
				  geosynthetic clay liner (GCL). The composite liner is one liner that consists
				  of three components: a geomembrane liner installed above and in uniform contact
				  with a GCL overlying a compacted clay liner with a minimum thickness of 18
				  inches (0.46 m) and a permeability of no more than 1.0 X
				  10-5 cm/sec. The composite liner shall be designed
				  and constructed in accordance with Subparagraphs (8), (9), and (10) of this
				  Paragraph.
(iii) A composite liner
				  utilizing two geomembrane liners. The composite liner consists of three
				  components; two geomembrane liners each with an overlying leachate drainage
				  system designed to reduce the maximum predicted head acting on the lower
				  membrane liner to less than one inch. The lower membrane liner shall overlie a
				  compacted clay liner with a minimum thickness of 12 inches (0.31m) and a
				  permeability of no more than 1.0 X 10-5 cm/sec. The
				  composite liner system shall be designed and constructed in accordance with
				  Subparagraphs (8) and (10) of this Paragraph.
(iv) An alternative base liner. An
				  alternative base liner system may be approved by the Division if the owner or
				  operator demonstrates through a two-phase modeling approach that the
				  alternative liner design meets the following criteria: the rate of leakage
				  through the alternative liner system will be less than or equal to the
				  composite liner system defined in Subpart (i) of this Part; and the design
				  shall ensure that maximum contaminant levels (MCL), promulgated under
				  40 CFR
				  141, will not be exceeded in the uppermost
				  aquifer at the relevant point of compliance as established in Rule .1631(a)(2)
				  of this Section.