Section 20320 - SWRCB -General Criteria for Containment Structures. (C15: s2541) (California Code of Regulations)

§ 20320. SWRCB -General Criteria for Containment Structures. (C15: s2541)

(a) Material Properties -Materials used in containment structures shall have appropriate chemical and physical properties to ensure that such structures do not fail to contain waste because of pressure gradients (including hydraulic head and external hydrogeologic forces), physical contact with the waste or leachate, chemical reactions with soil and rock, climatic conditions, the stress of installation, or because of the stress of daily operation.

(b) Applicable Permeants -Hydraulic conductivities specified for containment structures other than cover shall be relative to the fluids, including waste and leachate, to be contained. Hydraulic conductivities specified for final cover shall be relative to water.

(c) Determining Hydraulic Conductivity -Hydraulic conductivities shall be determined primarily by appropriate field test methods in accordance with accepted civil engineering practice. The results of laboratory tests with both water and leachate, and field tests with water (e.g., on the test pad), shall be compared to evaluate how the field permeabilities will be affected by leachate. It is acceptable for the discharger to use appropriate compaction tests in conjunction with laboratory hydraulic conductivity tests to determine field permeabilities as long as a reasonable number of field hydraulic conductivity tests are also conducted (e.g., a sealed double-ring infiltrometer test on the test pad).

(d) Soils Used in Containment Structures -Earthen materials used in containment structures other than cutoff walls and grout curtains shall consist of a mixture of clay and other suitable fine-grained soils which have the following characteristics, and which, in combination, can be compacted to attain the required hydraulic conductivity when installed. Liners made of such materials are referred to as "clay liners" in this subchapter.

(1) At least 30 percent of the material, by weight, shall pass a No. 200 U.S. Standard sieve.

(2) The materials shall be fine-grained soils with a significant clay content and without organic matter, and which is a clayey sand, clay, sandy or silty clay, or sandy clay under a soil classification system having industry-wide use [e.g., the "SC", "CL", or "CH" soil classes under ASTM Designation: "2487-93 Standard Classification of Soils for Engineering Purposes (Unified Soil Classification System)].

(e) Synopses -Construction standards for waste management units other than land treatment are given on Table 4.1 and in Figure 4.1.

Table 4.1. Construction Standards for Units [FN1]

Image

                 

Subsurface

Barriers

     
                       

Capacity of

  
                       

Precip &

  

Waste Mgmt

Type of Waste

     

Leachate

        

Drain. Control

  

Unit

Management

     

Collection and

        

Facilities

Seismic

Classification

Unit

Clay Liner [FN(2)]

Synthetic Liner

Rem. System

Interim Cover

Cutoff Walls

Grout Curtains

(Design Storm)

Design

Class II

Non MSW

Required [FN(5)],

Not required

Required,

Required

< =1x10-6

<=1x10-6 cm/sec

1000-year

Withstand

  

Landfill

<=1x10-6 cm/sec

  

blanket type

  

cm/sec [FN(11)]

  

24-hour

maximum

                       

precipitation

credible

                          

earthquake

Class II

MSW

Special [FN(13)]

Special [FN(13)]

Special [FN(13)]

Required

<=1x10-6

<=1x10-6 cm/sec

1000-year

Withstand

  

Landfill [FN(13)]

           

cm/sec [FN(11)]

  

24-hour

maximum

                       

precipitation

credible

                          

earthquake

Class II

Surface

Double or

Not required

Required with

Not required

<=1x10-6

<=1x10-6 cm/sec

1000-year

Withstand

  

Impoundment

single

  

double liner,

  

cm/sec [FN(11)]

  

24-hour

maximum

     

required [FN(6)],

  

blanket type

        

precipitation

credible

     

<=1x10-6 cm/sec

                 

earthquake

ClassII

Waste Pile

Optional [FN(4,5)],

Not required

May be

May be

<=1x10-6

<=1x10-6 cm/sec

1000-year

Withstand

     

<=1x10-6

  

required,

required

cm/sec [FN(11)]

  

24-hour

maximum

     

cm/sec

  

blanket type

        

precipitation

credible

                          

earthquake

Class III

Non MSW

Optional,

Not required

Required if

Required

<=1x10-6

<=1x10-6 cm/sec,

100-year

Withstand

  

Landfill

<=1x10-6 cm/sec

  

liner is required,

  

cm/sec, if

if required

24-hour

atleast the

     

(see s20260)

  

blanket or

  

required

  

precipitation

maximum

           

dendritic

           

probable

                          

earthquake

                          

(See

                          

s20370)

Class III

MSW

Special [FN(13)]

Special [FN(13)]

Special [FN(13)]

Required

<=1x10-6

<=1x10-6 cm/sec,

100-year

Withstand

  

Landfill [FN(13)]

           

cm/sec, if

if required

24-hour

at least the

                 

required

  

precipitation

maximum

                          

probable

                          

earthquake

                          

(See

                          

s20370)

[FN1] Applicable regulations in this article may provide for exemptions to certain requirements. s20310(d) describes applicability to existing facilities.

[FN2] All permeabilities specified in this table are maximum allowable permeabilities.

[FN3] [Reserved.] Note: This footnote left in Ch-15 (of Division 3, Title 23, CCR), as it applies only to Class I Units .

[FN4] A synthetic liner alone may be allowed based on nature of waste to be contained and duration of the operation. A waste pile with a synthetic liner alone may not be closed as a landfill pursuant to s21410 of this subchapter. The synthetic liner hydraulic conductivity shall be the same or less than that which would be required for a clay liner.

[FN5] Clay liner required unless Units are underlain by a substantial thickness of natural geologic materials with hydraulic conductivity of 1x10-6 cm/sec [i.e., 1 foot/year] or less.

[FN6] Single liner shall be a clay liner and removed or replaced as described in s20330. Double liner systems shall have either an outer clay liner or shall be underlain by a substantial thickness of natural geologic materials with an hydraulic conductivity of 1x10-6 cm/sec [i.e., 1 foot/year] or less to act as an outer liner.

[FN7] [Reserved.]

[FN8] [Reserved.]

[FN9] [Reserved.]

[FN10] [Reserved.]

[FN11] Cutoff walls required where there is potential for lateral movement of fluid, including waste or leachate, and the hydraulic conductivity of natural geologic materials is used for waste containment.

[FN12] For Units other than MSW landfills, the RWQCB can grant an exemption to this design storm requirement if the discharger can demonstrate that the integrity of facilities will not be jeopardized if this criterion is not met.

[FN13] All Class II or Class III landfills that received MSW at any time and that received solid waste after October 9, 1991 (MSW landfills) are subject to the additional state and federal requirements contained (or incorporated by reference) in SWRCB Resolution No. 93-62.

[FNFootnotes] for Figure 4.1: Summary of Liner Requirements for Classified Units (for MSW Landfills, see Additional Requirements in SWRCB Resolution No. 93-92).

[FNa] Requirements from Chapter 3, Subdivision 1 of this division.

[FNb] Designed to convey twice the anticipated volume of leachate; must ensure no buildup of hydraulic head on liner; blanket type required unless otherwise specified.

[FNc] Minimum 40 mils thick.

[FNd] Must be compatible with waste and/or leachate.

[FNe] Cutoff walls required where potential exists for lateral movement of waste or leachate.

[FNf] Acceptability of synthetic liner depends on nature of waste and duration of operation.

[FNg] Liner and waste to be removed at closure.

[FNh] Substantial thickness of natural geologic material hydraulic conductivity of 1 x 10-6 cm/sec (i.e., 1.0 foot/year). For MSW landfills, see SWRCB Resolution No. 93-62 for superseding containment system requirements.

[FNi] Minimum thickness of 2 feet; maximum hydraulic conductivity of 1 x 10-6 cm/sec (i.e., 1.0 foot/year). For MSW landfills, see SWRCB Resolution No. 93-62 for superseding containment system requirements.

[FNj] Liner removed or replaced before lower 25% (minimum 1 foot thickness) of the liner is penetrated by waste or leachate.

[FNk] Soil characteristics, distnace from waste to ground water, and other factors must ensure no impairment of beneficial uses of ground water. Leachate collection system required for sludge disposal. For MSW landfills, see SWRCB Resolution No. 93-62 for superseding containment system reuqirements.

[FNl] Minimum thickness of 1 foot; maximum hydraulic conductivity of 1 x 106 cm/sec (i.e., 1.0 foot/year). For MSW landfills, see SWRCB Resolution No. 93-62 for superseding containment system requirements.

[FNm] Dendritic system allowed if wastes in contact with the liner will remain permeable and liner is sloped toward the system to prevent ponding. For MSW landfills, see SWRCB Resolution No. 93-62 for superseding system requirements.

Image

Image

(1. New section, Table 4.1 and Figure 4.1 filed 6-18-97; operative 7-18-97 (Register 97, No. 25). 2. Change without regulatory effect amending Table 4.1 filed 3-17-98 pursuant to section 100, title 1, California Code of Regulations (Register 98, No. 12). 3. Change without regulatory effect amending Table 4.1 filed 5-19-2000 pursuant to section 100, title 1, California Code of Regulations (Register 2000, No. 20).)

Note: Authority cited: Section 1058, Water Code. Reference: Sections 13172 and 13360, Water Code; and Section 43103, Public Resources Code.

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