North Dakota Administrative Code
Title 33.1 - Department of Environmental Quality
Article 33.1-20 - Solid Waste Management and Land Protection
Chapter 33.1-20-08 - Disposal of Coal Combustion Residuals in Landfills and Surface Impoundments
Section 33.1-20-08-04 - Design criteria
Universal Citation: ND Admin Code ยง 33.1-20-08-04
Current through Supplement No. 394, October, 2024
1. New CCR landfills and any lateral expansion of a CCR landfill must be designed, constructed, operated, and maintained with the appropriate hydraulic barrier and leachate management system capable of collecting and removing leachate and contaminated surface water within the disposal unit during the operating period and postclosure period.
a. Prior to
construction of an overfill, the underlying CCR surface impoundment must meet
the requirements of subdivision d of subsection 3 of section
33.1-20-08-07.
b. Prior to
construction of the CCR landfill or any lateral expansion of the CCR landfill,
the owner or operator shall obtain a certification from a qualified
professional engineer and approval by the department that the design of the
composite liner (or, if applicable, alternative composite liner) and the
leachate collection and removal system meets the requirements of this
subsection.
c. Upon completion of
construction of the CCR landfill or any lateral expansion of the CCR landfill,
the owner or operator shall obtain a certification from a qualified
professional engineer and approval by the department that the composite liner
(or, if applicable, alternative composite liner) and the leachate collection
and removal system has been constructed in accordance with the requirements of
this subsection.
d. A composite
liner is required. The liner must consist of at least two feet [60.9
centimeters] of recompacted clay with a hydraulic conductivity not to exceed 1
x 10-7 centimeters per second overlain with at least a sixty mil flexible
membrane liner. The composite liner must be:
(1) Constructed of materials that have
appropriate chemical properties and sufficient strength and thickness to
prevent failure due to pressure gradients, including static head and external
hydrogeologic forces, physical contact with the CCR or leachate to which they
are exposed, climatic conditions, the stress of installation, and the stress of
daily operation;
(2) Constructed of
materials that provide appropriate shear resistance of the upper and lower
component interface to prevent sliding of the upper component including on
slopes;
(3) Placed upon a
foundation or base capable of providing support to the liner and resistance to
pressure gradients above and below the liner to prevent failure of the liner
due to settlement, compression, or uplift; and
(4) Installed to cover all surrounding earth
likely to be in contact with the CCR or leachate.
e. The department may consider an alternative
composite liner if all of the requirements of this subdivision are met. A
certification must be obtained from a qualified professional engineer stating
that:
(1) The alternative composite liner
consists of two components; the upper component consisting of, at a minimum, a
sixty-mil flexible membrane liner, and a lower component, that is not a
flexible membrane liner. If the lower component of the alternative liner is
compacted soil, the flexible membrane liner must be installed in direct and
uniform contact with the compacted soil.
(2) The transmissivity through the lower
component of the alternative composite liner is no greater than the
transmissivity through two feet [60.9 centimeters] of compacted soil with a
hydraulic conductivity of 1 x 10
-7 centimeters per second.
(3) The hydraulic conductivity for the two
feet [60.9 centimeters] of compacted soil used in the comparison shall be no
greater than 1 x 10
-7 centimeters per second.
(4) The hydraulic conductivity of any
alternative to the two feet [60.9 centimeters] of compacted soil must be
determined using recognized and generally accepted good engineering
practices.
(5) The transmissivity
comparison must be made using this equation, which is derived from Darcy's Law
for gravity flow through porous media:
Where:
Q = flow rate (cubic centimeters/second);
A = surface area of the liner (squared centimeters);
q = flow rate per unit area (cubic centimeters/second/squared centimeter);
k = hydraulic conductivity of the liner (centimeters/second);
h = hydraulic head above the liner (centimeters); and
t = thickness of the liner (centimeters).
(6) The alternative composite liner must meet
the requirements specified in paragraphs 1 through 4 of subdivision
d.
f. The drainage layer
must be designed and operated to minimize clogging during the active life and
post-closure care period and have a hydraulic conductivity of 1 x 10
-3 centimeters per second or greater
throughout. The drainage layer must have a sufficient thickness to provide a
transmissivity of 3 x 10
-2 centimeters squared per second or
greater.
g. The liner and leachate
removal system must be compatible with the waste and leachate.
h. The liner and leachate removal system must
maintain its integrity during the operating period and through postclosure
period.
i. The system must have a
collection efficiency of ninety percent or better and must be capable of
maintaining a hydraulic head of less than twelve inches [30.5 centimeters]"
above the liner.
j. The liner and
leachate removal system in combination with the final cover must achieve a site
efficiency of at least ninety-eight and one-half percent or better for
collection or rejection of the precipitation that falls on the site.
2. Liner design criteria for CCR surface impoundments.
a. For existing CCR
surface impoundments:
(1) No later than
twenty-four months after July 1, 2020, the owner or operator of an existing CCR
surface impoundment shall include with the application for a permit
modification that meets the requirements of this chapter, as required by
subsection 9 of section 33.1-20-08-02, documentation that such CCR unit was
constructed with one of the following:
(a) A
composite liner that meets the requirements of subdivision d of subsection
1;
(b) An alternative composite
liner that meets the requirements of subdivision e of subsection 1 or is
demonstrated, using recognized and generally accepted good engineering
practices, to have a total flux rate through the liner equal to or less than
the flux rate through a liner that meets the requirements of subdivision d of
subsection 1.
(2) The
hydraulic conductivity of the compacted soil must be determined using
recognized and generally accepted good engineering practices.
(3) An existing CCR surface impoundment is
considered to be an existing unlined CCR surface impoundment if either:
(a) The owner or operator of the CCR unit
determines that it is not constructed with a liner that meets the requirements
of paragraph 1; or
(b) The owner or
operator of the CCR unit fails to document whether the CCR unit was constructed
with a liner that meets the requirements of paragraph 1.
(4) All existing unlined CCR surface
impoundments are subject to the requirements of subdivision a of subsection 2
of section 33.1-20-08-07.
(5) The
owner or operator of the CCR unit shall obtain a certification from a qualified
professional engineer and approval from the department that an existing CCR
unit meets the requirements of this section.
b. New CCR surface impoundments and lateral
expansions of existing and new CCR surface impoundments must be designed,
constructed, operated, and maintained with a composite liner that meets the
requirements of subdivision d of subsection 1. The department may consider an
alternative liner that meets the requirements of subdivision e of subsection 1:
(1) Any liner specified in this section must
be installed to cover all surrounding earth likely to be in contact with CCR.
Dikes shall not be constructed on top of the composite liner.
(2) The owner or operator shall include
certification from a qualified professional engineer that the design of the
composite liner or, if applicable, the design of an alternative composite liner
complies with the requirements of this section, with the application for a new
permit or permit modification.
(3)
Upon completion, the owner or operator shall obtain certification from a
qualified professional engineer that the composite liner or if applicable, the
alternative composite liner has been constructed in accordance with the
requirements of this section.
3. Structural integrity criteria for existing CCR surface impoundments, new CCR surface impoundments, and lateral expansions of CCR surface impoundments.
a. The
requirements of paragraph 1 in this subdivision apply to all CCR surface
impoundments. The requirements in paragraphs 2 through 4 of this subdivision
apply to all CCR surface impoundments, except for those CCR surface
impoundments that are incised CCR units. If an incised CCR surface impoundment
is subsequently modified (e.g., a dike is constructed) such that the CCR unit
no longer meets the definition of an incised CCR unit, the CCR unit is subject
to the requirements of this section.
(1) The
owner or operator of the CCR unit shall place on or immediately adjacent to the
CCR unit a permanent identification marker, at least six feet [1.8 meters]
high, showing the permit number of the CCR unit, the name associated with the
CCR unit, and the name of the owner or operator of the CCR unit.
(2) Periodic hazard potential classification
assessments:
(a) The owner or operator of the
CCR unit shall conduct initial and periodic hazard potential classification
assessments of the CCR unit according to the time frames specified in paragraph
f. The owner or operator shall document the hazard potential classification of
each CCR unit as either a high-hazard potential CCR surface impoundment, a
significant-hazard potential CCR surface impoundment, or a low-hazard potential
CCR surface impoundment. The owner or operator also shall document the basis
for each hazard potential classification.
(b) The owner or operator of the CCR unit
shall obtain a certification from a qualified professional engineer stating
that the hazard potential classifications specified in this section were
conducted in accordance with the requirements of this section.
(3) Emergency action plan (EAP):
(a) Development of the plan. No later than
the time frames specified in paragraph f, the owner or operator of a CCR unit
determined to be either a high-hazard potential or significant-hazard potential
CCR surface impoundment under periodic hazard potential classification
assessments shall prepare and maintain a written EAP. The original EAP and any
amendments to the EAP must be approved by the department and placed in the
facility's operating record. At a minimum, the EAP must:
[1] Define the events or circumstances
involving the CCR unit that represent a safety emergency, along with a
description of the procedures that will be followed to detect a safety
emergency in a timely manner;
[2]
Define responsible persons, their respective responsibilities, and notification
procedures in the event of a safety emergency involving the CCR unit;
[3] Provide contact information of emergency
responders;
[4] Include a map which
delineates the downstream area that would be affected in the event of a CCR
unit failure and a physical description of the CCR unit; and
[5] Include provisions for an annual
face-to-face meeting or exercise between representatives of the owner or
operator of the CCR unit and the local emergency responders.
(b) Amendment of the plan:
[1] The owner or operator of a CCR unit that
is required to have a written EAP may amend the written EAP at any time. The
owner or operator shall amend the written EAP whenever there is a change in
conditions that would substantially affect the EAP in effect.
[2] The written EAP must be evaluated, at a
minimum, every five years to ensure the required information is accurate. As
necessary, the EAP must be updated and a revised EAP placed in the facility's
operating record.
(c)
Changes in hazard potential classification:
[1] If the owner or operator of a CCR unit
determines during a periodic hazard potential assessment that the CCR unit is
no longer classified as either a high-hazard potential CCR surface impoundment
or a significant-hazard potential CCR surface impoundment, then the owner or
operator of the CCR unit is no longer subject to the requirement to prepare and
maintain a written EAP beginning on the date the periodic hazard potential
assessment documentation is placed in the facility's operating
record.
[2] If the owner or
operator of a CCR unit classified as a low-hazard potential CCR surface
impoundment subsequently determines that the CCR unit is properly reclassified
as either a high-hazard potential CCR surface impoundment or a
significant-hazard potential CCR surface impoundment, then the owner or
operator of the CCR unit shall prepare a written EAP for the CCR unit within
six months of completing such periodic hazard potential assessment.
(d) The owner or operator of the
CCR unit shall submit the written EAP, and any subsequent amendment of the EAP
to the department for approval.
(e)
Activation of the EAP. The EAP must be implemented once events or circumstances
involving the CCR unit that represent a safety emergency are detected,
including conditions identified during periodic structural stability
assessments, annual inspections, and inspections by a qualified
person.
(4) The slopes
and pertinent surrounding areas of the CCR unit must be designed, constructed,
operated, and maintained with one of the forms of slope protection specified in
subparagraph a that meets all of the performance standards of subparagraph b.
(a) Slope protection must consist of one of
the following:
[1] A vegetative cover
consisting of grassy vegetation;
[2] An engineered cover consisting of a
single form or combination of forms of engineered slope protection measures;
or
[3] A combination of vegetative
cover and engineered cover.
(b) Any form of cover for slope protection
must meet all of the following performance standards:
[1] The cover must be installed and
maintained on the slopes and pertinent surrounding areas of the CCR
unit;
[2] The cover must provide
protection against surface erosion, wave action, and adverse effects of rapid
drawdown;
[3] The cover must be
maintained to allow for the observation of and access to the slopes and
pertinent surrounding areas during routine and emergency events;
[4] Woody vegetation must be removed from the
slopes or pertinent surrounding areas. Any removal of woody vegetation with a
diameter greater than one-half inch [12.7 millimeters] must be directed by a
person familiar with the design and operation of the unit and in consideration
of the complexities of removal of a tree or a shrubbery, who must ensure the
removal does not create a risk of destabilizing the unit or otherwise adversely
affect the stability and safety of the CCR unit or personnel undertaking the
removal; and
[5] The vegetative
height of grassy and woody vegetation must be maintained at a height that will
not be detrimental to the native grass cover.
b. The requirements of
subdivisions c through e apply to an owner or operator of a CCR surface
impoundment that either:
(1) Has a height of
five feet [1.5 meters] or more and a storage volume of twenty acre-feet [24670
cubic meters] or more; or
(2) Has a
height of twenty feet [6.1 meters] or more.
c. No later than in the time frames specified
in paragraph f for an existing impoundment, or included with the application
for a permit for a new CCR unit or permit modification for lateral expansion of
a CCR unit, the owner or operator of the CCR unit shall compile, to the extent
feasible, the information specified below:
(1) The name and address of the owner or
operator of the CCR unit, the name associated with the CCR unit, and the permit
number.
(2) The location of the CCR
unit identified on the most recent United States geological survey 7.5-minute
or 15-minute topographic quadrangle map, or a topographic map of equivalent
scale if a United States geological survey map is not available.
(3) A statement of the purpose for which the
CCR unit is being used.
(4) The
name and size in acres of the watershed within which the CCR unit
located.
(5) A description of the
physical and engineering properties of the foundation and abutment materials on
which the CCR unit is constructed.
(6) A statement of the type, size, range, and
physical and engineering properties of the materials used in constructing each
zone or stage of the CCR unit; the method of site preparation and construction
of each zone of the CCR unit; and the approximate dates of construction of each
successive stage of construction of the CCR unit.
(7) At a scale that details engineering
structures and appurtenances relevant to the design, construction, operation,
and maintenance of the CCR unit, detailed dimensional drawings of the CCR unit,
including a plan view and cross sections of the length and width of the CCR
unit, showing all zones, foundation improvements, drainage provisions,
spillways, diversion ditches, outlets, instrument locations, and slope
protection, in addition to the normal operating pool surface elevation and the
maximum pool surface elevation following peak discharge from the inflow design
flood, the expected maximum depth of CCR within the CCR surface impoundment,
and any identifiable natural or manmade features that could adversely affect
operation of the CCR unit due to malfunction or misoperation.
(8) A description of the type, purpose, and
location of existing instrumentation.
(9) Area-capacity curves for the CCR
unit.
(10) A description of each
spillway and diversion design features and capacities and calculations used in
their determination.
(11) The
construction specifications and provisions for surveillance, maintenance, and
repair of the CCR unit.
(12) Any
record or knowledge of structural instability of the CCR unit.
(13) Changes to the history of construction.
If there is a significant change to any information required in this
subdivision, the owner or operator of the CCR unit shall update the relevant
information, notify the department, and place it in the facility's operating
record.
d. Periodic
structural stability assessments.
(1) The
owner or operator of the CCR unit shall conduct initial and periodic structural
stability assessments and document whether the design, construction, operation,
and maintenance of the CCR unit is consistent with recognized and generally
accepted good engineering practices for the maximum volume of CCR and CCR
wastewater which can be impounded therein. The assessment must, at a minimum,
document whether the CCR unit has been designed, constructed, operated, and
maintained with:
(a) Stable foundations and
abutments;
(b) Slope protection
consistent with the requirements under paragraph 4 of subdivision a;
(c) Dikes mechanically compacted to a density
sufficient to withstand the range of loading conditions in the CCR
unit;
(d) Vegetated slopes of dikes
and surrounding areas must be maintained at a height above the slope of the
dike that will not be detrimental to the native grass cover, except for slopes
which have an alternate form or forms of slope protection;
(e) A single spillway or a combination of
spillways configured as stated below. The combined capacity of all spillways
must be designed, constructed, operated, and maintained to adequately manage
flow during and following the peak discharge from the event specified below.
[1] All spillways must be either:
[a] Of nonerodible construction and designed
to carry sustained flows; or
[b]
Earth- or grass-lined and designed to carry short-term, infrequent flows at
nonerosive velocities where sustained flows are not expected.
[2] The combined capacity of all
spillways must adequately manage flow during and following the peak discharge
from a:
[a] Probable maximum flood for a
high-hazard potential CCR surface impoundment;
[b] One thousand-year flood for a
significant-hazard potential CCR surface impoundment; or
[c] One hundred-year flood for a low-hazard
potential CCR surface impoundment.
(f) Hydraulic structures underlying the base
of the CCR unit or passing through the dike of the CCR unit that maintain
structural integrity and are free of significant deterioration, deformation,
distortion, bedding deficiencies, sedimentation, and debris which may
negatively affect the operation of the hydraulic structure; and
(g) For CCR units with downstream slopes
which can be inundated by the pool of an adjacent water body, such as a river,
stream, or lake, downstream slopes that maintain structural stability during
low pool of the adjacent water body or sudden drawdown of the adjacent water
body.
(2) The periodic
structural stability assessment described in this subdivision must identify any
structural stability deficiencies associated with the CCR unit in addition to
recommending corrective measures. If a deficiency or a release is identified
during the periodic assessment, the owner or operator of the CCR unit must
remedy the deficiency or release as soon as feasible and prepare documentation
detailing the corrective measures taken.
(3) The owner or operator of the CCR unit
shall obtain a certification from a qualified professional engineer stating
that the initial assessment and each subsequent periodic assessment was
conducted in accordance with the requirements of this section.
e. Periodic safety factor
assessments.
(1) The owner or operator shall
conduct an initial and periodic safety factor assessments for each CCR unit and
document whether the calculated factors of safety for each CCR unit achieve the
minimum safety factors specified below for the critical cross section of the
embankment. The critical cross section is the cross section anticipated to be
the most susceptible of all cross sections to structural failure based on
appropriate engineering considerations, including loading conditions. The
safety factor assessments must be supported by appropriate engineering
calculations.
(a) The calculated static
factor of safety under the long-term, maximum storage pool loading condition
must equal or exceed 1.50.
(b) The
calculated static factor of safety under the maximum surcharge pool loading
condition must equal or exceed 1.40.
(c) The calculated seismic factor of safety
must equal or exceed 1.00.
(d) For
dikes constructed of soils that have susceptibility to liquefaction, the
calculated liquefaction factor of safety must equal or exceed 1.20.
(e) For new CCR surface impoundments and
lateral expansions of a CCR impoundment, the calculated static factor of safety
under the end-of-construction loading condition must equal or exceed 1.30. The
assessment of this loading condition is only required for the initial safety
factor assessment and is not required for subsequent assessments.
(2) The owner or operator of the
CCR unit shall obtain a certification from a qualified professional engineer
stating that the initial assessment and each subsequent periodic assessment
specified in this section meets the requirements of this section.
f. Time frames for periodic
assessments.
(1) Initial assessment. Except as
provided in this subdivision, the owner or operator of an existing CCR unit
shall complete and include the initial assessments required by this section
with the application for a permit modification that meets the requirements of
this chapter within twenty-four months of July 1, 2020, as required by
subsection 9 of section 33.1-20-08-02, or for a new CCR unit or lateral
expansion of a CCR unit, with the application for a new permit or permit
modification. The owner or operator has completed an initial assessment when
the assessment has been approved by the department placed in the facility's
operating record.
(2) The owner or
operator of an existing CCR surface impoundment may elect to use a previously
completed assessment to serve as the initial assessment required by this
section, provided that the previously completed assessment:
(a) Was completed no earlier than April 17,
2013; and
(b) Meets the applicable
requirements of this section.
(3) Frequency for conducting periodic
assessments. The owner or operator of the CCR unit shall conduct and complete
the assessments required by this section every five years. The date of
completing the initial assessment is the basis for establishing the deadline to
complete the first subsequent assessment. If the owner or operator elects to
use a previously completed assessment in lieu of the initial assessment, the
date of the report for the previously completed assessment is the basis for
establishing the deadline to complete the first subsequent assessment. The
owner or operator may complete any required assessment prior to the required
deadline provided the owner or operator places the completed assessment into
the facility's operating record within a reasonable amount of time. In all
cases, the deadline for completing subsequent assessments is based on the date
of completing the previous assessment. For purposes of this section, the owner
or operator has completed an assessment when the relevant assessment has been
approved by the department and placed in the facility's operating
record.
(4) Failure to document
minimum safety factors during the initial assessment for new CCR surface
impoundments or lateral expansions of a CCR surface impoundment. Until an owner
or operator of a CCR unit documents that the calculated factors of safety
achieve the minimum safety factors specified in paragraph 1 of subdivision e,
the owner or operator is prohibited from placing CCR in such unit.
(5) Closure of the CCR unit. An owner or
operator of a CCR unit who either fails to complete a timely safety factor
assessment or fails to demonstrate minimum safety factors as required by this
section is subject to the closure requirements of subdivision b of subsection 2
of section 33.1-20-08-07.
General Authority: NDCC 23.1-08-03
Law Implemented: NDCC 23.1-08-03, 23.1-08-04
Disclaimer: These regulations may not be the most recent version. North Dakota may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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