401 KAR 48:080. Liner and cap design requirements for contained landfills

Link to law: http://www.lrc.ky.gov/kar/401/048/080.htm
Published: 2015

      401 KAR 48:080.

Liner and cap design requirements for contained landfills.

 

      RELATES TO: KRS

224.01, 224.10, 224.40, 224.43, 224.99

      STATUTORY AUTHORITY:

KRS 224.10-100, 224.40-305

      NECESSITY, FUNCTION,

AND CONFORMITY: KRS Chapter 224 requires the cabinet to adopt rules and

administrative regulations for the managing, processing, or disposal of solid

wastes. KRS 224.40-305 requires that persons engaging in the managing,

processing, or disposal of waste obtain a permit. This chapter establishes the

minimum technical standards for solid waste sites or facilities. This

administrative regulation sets forth the liner and cap design requirements for

contained landfills.

 

      Section 1. Liners

for Contained Landfills. At a minimum all contained landfills shall have:

      (1) A primary

composite liner as specified in Sections 2 and 7 of this administrative

regulation; and

      (2) A secondary

composite liner that:

      (a) Meets the

secondary liner criteria specified in Sections 2 and 7 of this administrative

regulation; or

      (b) Is a naturally

occurring material provided that such natural material:

      1. Shall be

equivalent to material with a minimum thickness of twenty (20) feet with a

maximum permeability of 1 x 10-7 centimeters per second;

      2. Shall lie above

the uppermost aquifer; and

      3. Shall

continuously underlie the landfill site or facility and be demonstrated to have

sufficient integrity to protect the uppermost aquifer from contamination in the

event of a breech of the primary composite liner.

 

      Section 2.

Components of Contained Landfill Liner Systems. Once the subgrade is

established, the primary and secondary liner systems shall consist of the

layers, listed in subsections (1) through (3) of this section.

      (1) The secondary

liner system shall consist of the following layers, listed from bottom to top:

      (a) A twelve (12)

inch soil layer with a permeability of 1 x 10-7 centimeters per

second as specified in Section 4 of this administrative regulation;

      (b) A secondary

synthetic liner as specified in Section 5 of this administrative regulation;

      (c) A twelve (12)

inch drainage layer with a permeability of 1 x 10-3 centimeters per

second; and

      (d) A filter fabric

or other material approved by the cabinet.

      (2) The secondary

liner layer specified in subsection (1)(a) and (b) of this section may be

substituted for by a naturally occurring material as specified in Section 1(2)

of this administrative regulation.

      (3) The primary

liner shall consist of the following layers, listed from bottom to top:

      (a) A thirty-six

(36) inch clay layer with a permeability of 1 x 10-7 centimeters per

second as specified in Sections 4, 6 and 7 of this administrative regulation;

      (b) A primary

synthetic liner as specified in Section 5 of this administrative regulation;

      (c) A twelve (12)

inch drainage layer with permeability of 1 x 10-2 centimeters per

second or a layer of equivalent performance as specified in Section 6 of this

administrative regulation; and

      (d) A filter fabric

or other material approved by the cabinet to protect the integrity of the

drainage layer.

 

      Section 3. Specific

Landfill Subgrade Requirement. The landfill subgrade is the uppermost in situ

rock layer, in situ soil layer or select fill that shall be graded and prepared

for landfill construction. For lateral expansions adjacent to existing

landfills, the cabinet may approve encroachment upon the existing landfill's

side slope if a leachate barrier system is designed and construction to

intercept leachate and prevent its migration into the existing landfill.

      (1) Materials

required. The landfill subgrade material shall be free of organic material and

consist of bedrock, on-site soils, or any select fill with the structural

ability to support the landfill maximum load with a factor of safety of two

(2.0).

      (2) Construction

requirements. The landfill subgrade shall be graded in accordance with the

requirements of the approved engineering plans, report, and specifications. The

material shall be sufficiently dry and structurally sound to ensure that the

first lift and all succeeding lifts of soil placed over the landfill subgrade

can be adequately compacted to the design requirements.

      (3) Certification

requirements. At a minimum, the subgrade surface shall be inspected in

accordance with the following requirements:

      (a) Before placing any

material over the subgrade, the project engineer shall visually inspect the

exposed surface to evaluate the suitability of the subgrade and ensure that the

surface is properly compacted, smooth, uniform, and has positive surface

drainage;

      (b) Soil subgrade

shall be proof-rolled using a minimum 100,000 pound loaded four (4) tire

scraper (twenty (20) cubic yard size) or equivalent procedure and equipment

approved by the cabinet;

      (c) Soil subgrade

shall be tested for density and moisture content at a minimum frequency of nine

(9) tests per acre. The subgrade shall be compacted to a density of at least

ninety (90) percent of the standard proctor; and

      (d) Sufficient cross

sections shall be taken showing the finished elevation of the completed

subgrade, referenced to existing site control. These cross sections shall serve

as documentation and reference data for all future volume calculations.

 

      Section 4. Specific

Soil Component Requirements of Landfill Liner Systems. The soil component of

the landfill liner system shall be a continuous layer of low permeability soil

constructed to control fluid migration.

      (1) Low permeability

soil components shall have a maximum remolded coefficient of permeability of 1

x 10-7 centimeters per second. The soil shall be placed without

damaging any collection and removal system components. The soil material shall

be substantially free of tree roots, wood or other decayable materials and

large rock. The soils shall be compacted to a minimum of ninety-two (92)

percent of the standard proctor density.

      (2) Construction

requirements. The project engineer shall ensure that the soil component of the

liner system installation conforms to the following minimum requirements:

      (a) The soil

component of the liner system shall be placed on a slope of no less than three

(3) percent toward the main leachate collection line and one (1) percent along

the main leachate collection line to promote positive drainage across the liner

surface and at a maximum slope not greater than fifty (50) percent.

      (b) Compaction shall

be performed by properly controlling the moisture content, lift thickness, and

other necessary details to obtain the density, moisture and permeability

characteristics specified in 401 KAR Chapter 48. The maximum final compacted

thickness of each lift of soil material shall be six (6) inches or the

thickness necessary to protect the integrity of underlying components and

achieve the required liner performance standards.

      (c) During

construction the moisture content of the soil component of the liner system

shall be maintained within the range identified in accordance with the

certification requirements to ensure that the remolded lift attains the

required permeability.

      (3) Certification

requirements. The project engineer shall include in the construction

certification report a discussion of all required quality assurance and quality

control testing. The testing procedures and protocols shall be submitted and

approved by the cabinet. The results of all testing shall be included in the construction

certification report including documentation of any failed test results,

descriptions of the procedures used to correct the improperly installed

material, and statements of all retesting performed in accordance with the

following requirements:

      (a) The project

engineer shall certify the results of the quality control testing of any soil

liner materials. The intent of the quality control testing is to ensure that

the specified material meets the permeability requirements of subsection (1) of

this section. Before and during construction of the soil component of the liner

system, the following minimum testing and classification shall be performed:

      1. Determination of

the classification of soils for engineering purposes using test methods

approved by the cabinet for each 10,000 cubic yards of soil material placed and

each time significant soil material changes are noted:

      2. One (1) analysis

of soil particle size for every 2,000 cubic yards of soil liner material placed

from the same source. Additional analyses shall be performed if the source of

material is changed or if a different soil type is encountered from the same

source.

      3. One (1) Atterberg

limits analysis of plastic and liquid limit and plasticity index as approved by

the cabinet for every 2,000 cubic yards of soil liner material placed;

      4. One (1) moisture

content test for every 2,000 cubic yards of material placed; and

      5. A minimum of one

(1) comparison of the moisture-density-permeability relation for every 20,000

cubic yards of material placed and one (1) each time soil material changes are

noted. A minimum of three (3) laboratory permeability tests shall be performed

using a triaxial cell with backpressure. The specimen used for each

permeability test shall be remolded at the same moisture content which shall be

equal to or not greater than four (4) percent above the optimum moisture

content. The comparison shall be based on a semilog plot of percent maximum

density versus permeability with at least one (1) point below and one (1) point

above the target permeability value.

      (b) Quality

assurance testing included in this paragraph shall be compared to and evaluated

against the quality control testing of paragraph (a) of this subsection where

applicable. Quality assurance testing shall include:

      1. At least nine (9)

density tests per acre per lift of soil material placed;

      2. A minimum of nine

(9) moisture content tests per acre per lift of soil material placed; and

      3. All

moisture-density testing performed using nuclear methods.

 

      Section 5. Specific

Synthetic Liner Requirements. A synthetic liner is a low permeability manmade

material having a maximum coefficient of permeability of 1 x 10-12

centimeters per second and is used to control fluid migration from landfills.

      (1) Materials required.

The synthetic liner material shall have a demonstrated hydraulic conductivity

less than 1 x 10-12 centimeters per second and chemical and physical

resistance not adversely affected by waste placement or leachate generated and

a maximum water vapor transmission rate of 0.04 grams per square meter per day

for forty (40) mil nominal thickness material and 0.03 grams per square meter

per day for sixty (60) mil nominal thickness material. Documentation shall be

submitted to ensure chemical compatibility of the synthetic liner material

chosen or, in absence of the appropriate documentation, chemical compatibility

testing shall be performed using a test method acceptable to the cabinet.

      (2) Construction

requirements. Synthetic liners shall be installed in accordance with the

requirements of the approved engineering plans, report, and specifications and

manufacturer's recommendations. The project engineer shall ensure that the

synthetic liner installation, at a minimum, shall conform with the following:

      (a) The synthetic

liner shall have a nominal thickness of sixty (60) mils;

      (b) The synthetic

liner shall be installed on a subgrade that has a minimum three (3) percent

slope to promote positive drainage;

      (c) Synthetic liners

installed on slopes greater than twenty-five (25) percent shall be designed to

withstand the calculated tensile forces acting upon the synthetic material, and

shall ensure that overall slope stability is maintained;

      (d) The surface of

the supporting soil above which the synthetic liner shall be installed shall be

reasonably free of stones, organic matter, irregularities, protrusions, loose

soil, and any abrupt changes in grade that may damage the synthetic liner. The

supporting soil shall conform to the requirements of Section 4 of this administrative

regulation;

      (e) The anchor

trench shall be excavated to the length and width prescribed on the approved

design drawings;

      (f) Field seams

shall be oriented parallel to the line of maximum slope, i.e., oriented along,

not across the slope. In corners and irregularly-shaped locations, the number

of field seams shall be minimized;

      (g) The materials

shall be seamed using an appropriate method acceptable to the cabinet. Seam

testing shall be in accordance with the requirements of subsection (3) of this

section;

      (h) The seam area

shall be free of moisture, dust, dirt, debris, and foreign material of any kind

before seaming; and

      (i) Field seaming

shall be prohibited when the conditions including ambient air, temperature,

precipitation, and wind do not meet the engineers recommendations based upon

the suppliers specifications.

      (3) Certification

requirements. The project engineer shall include in the construction

certification report a discussion of the approved data resulting from the

quality assurance and quality control testing required in this paragraph. The

results of all testing shall be included in the construction certification

report including documentation of any failed test results, descriptions of the

procedures used to correct the failed material, and statements of all retesting

performed.

      (a) The project

engineer shall certify the quality control testing of the synthetic liner

ensuring that the material and workmanship meet the requirements of the

approved engineering plans, reports, and specifications. Before installing a

synthetic liner, the following information shall be available to the project

engineer for approval:

      1. Origin and

identification of the raw materials used to manufacture the synthetic liner;

      2. Copies of quality

control certificates issued by the producer of the raw materials used to

manufacture the synthetic liner; and

      3. Reports of tests

conducted to verify the quality of the raw materials used to manufacture the

synthetic liner. Tests for specific gravity, melt flow index, and percent

carbon black shall be performed using a method acceptable to the cabinet.

      (b) The project

engineer shall verify through appropriate documentation that the quality

control testing of any synthetic rolls fabricated into blankets at the factory

took place in accordance with the following requirements:

      1. The synthetic

liner was continuously inspected for uniformity, damage, imperfections, holes,

cracks, thin spots, and foreign materials. Additionally, the synthetic liner

shall be inspected for tears, punctures, and blisters. Any imperfections shall

be immediately repaired and reinspected;

      2. Nondestructive

seam testing was performed on all fabricated seams over their full length using

a test method acceptable to the cabinet; and

      3. A destructive

seam testing was performed on a minimum of two (2) samples per blanket. The

samples shall be taken from extra material at the beginning or end of blanket

seams such that the blanket is not damaged and the blanket geometry is not

altered. The size of the sample taken shall be large enough to perform the

required testing. An independent laboratory acceptable to the cabinet shall

perform the required testing on the samples taken. If a sample fails a

destructive test, the entire seam length shall be reconstructed or repaired

using a method acceptable to the cabinet and retested using nondestructive seam

testing over its full length using a test method acceptable to the cabinet.

      (c) Quality

assurance testing performed in the field under the supervision of the project

engineer shall assure conformity of the synthetic liner installation with the

engineering plans, reports, and specifications submitted in accordance with the

following requirements:

      1. During the

construction phase, the synthetic liner shall be inspected for uniformity,

damage, and imperfections. The liner shall be inspected for tears, punctures,

or blisters. Any imperfections shall be immediately repaired and reinspected;

      2. All field seams

shall be nondestructively tested in accordance with the procedures listed in

this clause using a test method acceptable to the cabinet. The project engineer

shall supervise all nondestructive testing; record the location, date, test

unit number, name of tester, and results of all testing; inform the installer

of any required repairs; and overlay all seams which cannot be nondestructively

tested with the same synthetic liner. The seaming and patching operation shall

be inspected by the project engineer for uniformity and completeness; and

      3. Destructive testing

shall be performed on the synthetic liner seam sections in accordance with the

following requirements and using test methods acceptable to the cabinet. Seam

samples for testing shall be taken as follows: a minimum of one (1) test per

every 500 feet of seam length unless a more frequent testing protocol is agreed

upon by the installer and project engineer; additional test locations may be

determined during seaming at the project engineer's discretion; and all test

locations shall be appropriately documented. The project engineer shall approve

the sample size to be taken. The sample size shall be predetermined as being

large enough to perform the required testing. An independent laboratory

acceptable to the cabinet shall perform the required testing which shall

include, as a minimum, testing for seam strength and peel adhesion using

testing procedures acceptable to the cabinet. If a sample fails destructive

testing the project engineer shall ensure that the seam is reconstructed

between the location of the sample which failed and the location of the next

acceptable sample; or the welding path is retraced to an intermediate location

at least ten (10) feet from the location of the sample which failed the test,

and a second sample is taken for an additional field test. If this second test

sample passes, the seam shall then be reconstructed between the location of the

second test and the original sampled location. If the second sample fails, this

process shall be repeated. All acceptable seams shall lie between two (2)

locations where samples passed the required test procedures of this section and

include one (1) test location along the reconstructed seam.

 

      Section 6. Primary

Liner System. The liner shall be designed using the following specifications:

      (1) A thirty-six

(36) inch thick low permeability soil layer having a remolded coefficient of

permeability of 1 x 10-7 centimeters per second and compacted to a

minimum of ninety-two (92) percent standard proctor density;

      (2) A sixty (60) mil

thick synthetic liner having a maximum coefficient of permeability of 1 x 10-12

centimeters per second and not adversely affected by the leachate or loading

from the operational landfill;

      (3) A leachate

collection and removal system consisting of a twelve (12) inch thick granular

material layer with a leachate collection pipe network. This collection system

shall be designed to achieve a maximum hydraulic head on the primary composite

liner no greater than twelve (12) inches. The granular material shall have a

minimum coefficient of permeability of 1 x 10-2 centimeters per

second. The physical and chemical properties of the granular material and pipe

shall not be adversely affected by the loads or leachate generated by the

operations of the landfill. Alternate materials proposed to function as a

substitute for the granular soil layer shall be demonstrated to be equivalent

in performance for leachate drainage and load bearing properties; and

      (4) The leachate

collection system shall contain a perforated piping system capable of removing

leachate from the top surface of the low permeability solid component, and

conveying it to a collection point. The drainage system shall meet the

following requirements:

      (a) Main leachate

collection pipes shall have a minimum diameter of eight (8) inches and shall be

designed to withstand static and dynamic loads that may be encountered;

      (b) The sheet flow

drainage distances to the lateral drainage pipes shall not exceed fifty (50)

feet;

      (c) The lateral

pipes shall be installed primarily perpendicular to flow;

      (d) The minimum

diameter of lateral perforated pipes shall be four (4) inches and shall be

designed to withstand static and dynamic loads that may be encountered. The

materials used shall at a minimum conform to the specifications for ASTM

schedule eighty (80) pipe;

      (e) The minimum

slope for the piping system shall be one (1) percent;

      (f) The leachate

collection tank shall be a minimum of 1,000 gallons. Additional capacity shall

be provided to store leachate for a minimum of fifteen (15) days production at

peak production rates during operation and closure;

      (g) The method of

leachate disposal shall be described. When it is discharged to the sediment

structure, a treatment plant is proposed or other method of discharge is

proposed, the KPDES permit shall reflect this provision. When an off-site

wastewater treatment plant is used, the applicant shall provide written

documentation showing the acceptance of the waste. The criteria for disposal at

the wastewater treatment plant shall be stated. The leachate collection system

shall have a method to measure the quantity of leachate managed at the site;

      (h) The leachate

collection pipe system shall be designed to allow internal inspection, cleaning

and maintenance; and

      (i) The maximum

design head of the leachate collection system shall be one (1) foot.

      (5) A geosynthetic

filter fabric or other suitable material shall be placed above the drainage

layer to prevent clogging.

 

      Section 7. Slope

Considerations. (1) For bottom slopes of less than or equal to ten (10)

percent, the owner or operator shall have a liner system meeting the

requirements of Section 1 of this administrative regulation.

      (2) For bottom

slopes of ten (10) to twenty-five (25) percent, the owner or operator shall

have a liner system meeting the requirements of Section 2(3) of this

administrative regulation, except that the owner or operator may replace the

granular soil layers in the leachate collection and hydraulic relief systems

with synthetic drainage netting.

      (3) For bottom

slopes of more than twenty-five (25) percent, the thickness of the soil

required in Sections 2(3)(a) and (6)(1) of this administrative regulation shall

be reduced by no more than twelve (12) inches.

 

      Section 8. Final Cap

System. At a minimum the final cap shall consist of a layered system. Each

layer shall have the same slope of between five (5) and twenty-five (25)

percent. The components, listed from bottom to top, are:

      (1) A filter fabric

or other material approved by the cabinet;

      (2) A twelve (12) inch

sand gas venting system with a minimum hydraulic permeability of 1 x 10-3;

      (3) A filter fabric

or other material approved by the cabinet;

      (4) An eighteen (18)

inch clay layer with a maximum permeability of 1 x 10-7 centimeters

per second;

      (5) For areas of the

final cap with a slope of less than fifteen (15) percent, a twelve (12) inch

drainage layer with a minimum permeability of 1 x 10-3 centimeters

per second; and

      (6) A thirty-six

(36) inch vegetative soil layer.

 

      Section 9. Final Cap

System Specifications. The specifications for final cap component layers are:

      (1) A low

permeability clay layer listed in Section 8(4) of this administrative

regulation shall be compacted to a minimum of ninety-two (92) percent of the

standard proctor density;

      (2) A drainage layer

specified in Section 8(5) of this administrative regulation shall be compacted

to a minimum of eighty-five (85) percent of the standard proctor density. Field

tile drainage shall be specified as necessary to relieve water captured by this

drainage layer;

      (3) A vegetative

soil layer as specified in Section 8(6) of this administrative regulation shall

be sufficient to sustain vegetative growth and prevent root penetration of the

underlying layers. A thicker layer may be required by the cabinet to properly

retain moisture or meet closure care requirements.

      (4) Drainage berms

of at least one (1) foot in height or two (2) feet in width shall be placed at

the following intervals for the following slopes:

      (a) 150 feet at

greater than ten (10) percent slope;

      (b) 200 feet at

slope between five (5) and ten (10) percent. In lieu of drainage berms, the

owner or operator may substitute a design with a horizontal terrace of at least

fifteen (15) feet width on the slope for every twenty-five (25) feet maximum

rise in elevations on the slope. The slope of the terrace shall be five (5)

percent into the fill and drainage ditches shall be designed for each terrace

to convey precipitation flows. The maximum slope between terraces shall not

exceed twenty-five (25) percent; or

      (c) The applicant

shall may adjust the drainage berm specifications with design calculations

based upon characteristics of soils and cover.

      (5) A synthetic

liner with a minimum thickness of forty (40) mils and a maximum coefficient of

permeability of 1 x 10-12 centimeters per second may be substituted

for the low-permeability soil cover in Section 8(4) of this section.

      (6)(a) The final

cover shall be revegetated.

      (b) The soil-water

pH shall be adjusted and the soil fertilized based upon current soil test

results.

      (c) The seed bed

shall be prepared and temporary nurse crops and permanent grasses planted in

accordance with the approved closure plan within thirty (30) days of completion

of final cover grading.

      (d) The owner or

operator shall repeat the above as necessary to achieve permanent vegetation.

      (e) Erosion controls

shall be addressed in the closure plan and constructed as required. All slopes

over three (3) percent shall have controls applied at the time of seeding.

      (f) The owner or

operator shall inspect all areas and perform maintenance and revegetation. At a

minimum, the site shall be initially inspected according to this table:



Seeding

Date





Follow-up

Inspection

Date





Complete

Revegetation

By







Aug.

16-Oct. 15





April

1





June

15







Oct.

16-Mar. 15





June

1





June

30







Mar.

16-Jun. 15





September

1





October

15







Jun.

16-Aug. 15





October

1





October

30





 

      After the initial

inspection, follow-up inspections shall be made on April 1, and September 1,

with revegetation completed by June 15 and October 15.

      (g) After one (1)

year, all areas larger than 100 square feet with less than forty (40) percent

vegetation shall be tested to determine required revegetation, which shall be

completed by September 30.

 

      Section 10.

Structural Integrity of Cap and Liner. The design engineer shall analyze the

structural integrity of the site, the subbase, each component of the composite

liner, each component of the final cover, the composite liner system and the

final cap as a system. Modifications to the design shall be provided where

necessary, to achieve a minimum factor of safety of two (2) for the subbase,

one and one-fourth (1.25) for the structural design of the facility liner

components, and one and one-half (1.5) for the final cover system. Synthetic

liner material and structural synthetic materials shall be designed for a

maximum elongation of ten (10) percent.

 

      Section 11.

Alternative Specifications. Alternative specifications may be used only after

approval by the cabinet upon a demonstration by a qualified registered

professional engineer that they shall result in performance with regard to

safety, stability and environmental protection equal to or better than that

resulting from designs complying with the specifications of this administrative

regulation. (16 Ky.R. 1776; Am. 2211; 2374; eff. 5-8-90.)
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