132 Neb. Admin. Code, ch. 4, § 003

Current through September 17, 2024

Section 132-4-003 - Design Criteria

The construction and design of all fossil fuel combustion ash disposal areas shall:

003.01 Be protective of human health and the environment;

003.02 Not result in pollution of the waters of the state; and

003.03 In the case of a new fossil fuel combustion ash disposal area or a lateral expansion of an existing fossil fuel combustion ash disposal area, the construction and design plans shall include the following:

003.03A A description of the sequence of earth materials at the proposed facility to a depth sufficient to assure the reliability of the facility design;

003.03B A schedule of construction and a construction quality assurance plan as described in 003.04C;

003.03C Data obtained from soil samples taken from the proposed facility site which describe the soil classification, grain size distribution, permeability, compatibility, and ion-exchange properties of the subsurface materials for those strata which are essential to the design of the facility; and

003.03D If exploration holes are drilled to obtain data, information showing the manner of plugging and sealing such holes.

003.04 The construction and design plans for all new or lateral expansions of an existing fossil fuel combustion ash disposal area shall also include the following documentation.

003.04A A liner designed and constructed according to one of the following designs:

003.04A1 With a composite liner consisting of two components: the upper component must consist of a minimum 30-mil flexible membrane liner (FML); and the lower component must consist of at least a two (2) foot layer of compacted soil with a hydraulic conductivity of no more than 1 x 10^-7 cm/sec. FML components consisting of high density polyethylene (HDPE) shall be at least 60-mil. thick. The FML must be installed in direct and uniform contact with the compacted soil component; or

003.04A2 In accordance with a design approved by the Department, alternate designs shall ensure that the concentration values listed in Appendix III will not be exceeded in the uppermost aquifer at the relevant point of compliance, as specified by the Department under 003.04D of this chapter. The Department shall consider the following factors when approving the design of liner systems:

003.04A2(a) The hydrogeologic characteristics of the facility and the surrounding land;

003.04A2(b) The climatic characteristics of the area;

003.04A2(c) The volume and type of fossil fuel combustion ash to be deposited; and

003.04A2(d) The volume and physical and chemical characteristics of the leachate.

003.04A3 All required compacted soil components shall be constructed in lifts which do not exceed six (6) inches in thickness.

003.04A3(a) Uniform compaction of the lifts shall be assured through the use of appropriate equipment. Liners shall be supported by material of sufficient bearing strength to prevent subsidence and failure of any component. The bearing strength shall be documented through materials testing.

003.04B A leachate collection and treatment system shall be constructed where necessary to protect the waters of the state. Any required discharge permit shall be obtained from the Department. The leachate collection system shall be maintained as required by section 006.

003.04B1 Leachate collection systems shall be designed and constructed to maintain less than a 30-cm. depth of leachate over the liner.

003.04C A construction quality assurance plan for engineered containment systems and leachate collection systems shall be submitted with the application. The plan shall assure adequate construction and testing of the containment system components as called for in design specifications in the facility plan. The construction quality assurance plan shall be prepared and signed by a professional engineer registered in the State of Nebraska.

003.04D The relevant point of compliance noted in 003.04A2 of this chapter shall be located at the waste management unit boundary. The applicant may request the establishment of an alternate relevant point of compliance. The alternate relevant point of compliance shall be no more than 150 meters from the waste management unit boundary and shall be located on land owned by the fossil fuel combustion ash disposal area permittee. The Department will base the decision to approve or deny the applicant's request upon consideration of the following factors:

003.04D1 The hydrogeologic characteristics of the facility and the surrounding land;

003.04D2 The volume and physical and chemical characteristics of the leachate;

003.04D3 The quantity, quality and direction of flow of ground water;

003.04D4 The proximity and withdrawal rate of the ground water users;

003.04D5 The availability of alternative drinking supplies;

003.04D6 Method of operation as outlined in the operational plan;

003.04D7 The existing quality of the ground water, including other sources of contamination and their cumulative impacts on the ground water, and whether the ground water is currently used or reasonably expected to be used for drinking water;

003.04D8 Public health, safety, and welfare effects; and

003.04D9 Practicable capability of the owner or operator.

003.04E Fossil fuel combustion ash disposal area run-on/run-off control systems shall be designed, constructed and maintained to meet the following criteria:

003.04E1 A run-on control system to prevent flow onto the active portion of the fossil fuel combustion ash disposal area during the peak discharge from a twenty-five (25) year storm; and

003.04E2 A run-off control system from the active portion of the fossil fuel combustion ash disposal area to collect and control, at least, the water volume resulting from a twenty-four (24) hour, twenty-five (25) year storm.

003.04E3 Surface water courses and run-off shall be diverted from the fossil fuel combustion ash disposal area by devices such as trenches, conduits and proper grading to minimize infiltration and erosion of cover material. The fossil fuel combustion ash disposal area shall be constructed and graded so as to promote rapid surface water run-off without excessive erosion.

003.04E4 Run-off from the active portion of the fossil fuel combustion ash disposal area shall be handled in accordance with 004.05.

003.04E5 Regrading shall be done as required during construction, after completion, and during the placement of fossil fuel combustion ash to avoid ponding of precipitation and to maintain cover material integrity. On-site drainage structures and channels shall be designed for at least a twenty-four (24) hour, twenty-five (25) year storm.

132 Neb. Admin. Code, ch. 4, § 003

Amended effective 5/17/2016.