EPA/530-SW-85-012



     Guidance on Implementation of the Minimum Technological
       Requirements of HSWA of 1984, Respecting Liners and
                   Leachate Collection Systems

          Reauthorization Statutory Interpretation # 5D


     On November 8, 1984, the President signed into law the

Hazardous and Solid Waste Amendments of 1984 (HSWA).  Among the

provisions of this new law are minimum technological requirements

for hazardous waste landfills, surface impoundments, and waste

piles.   These provisions are found in Sections 3004(o) and 3015

of the Resource Conservation and Recovery Act (RCRA), as amended

by HSWA.   With respect to liners and leachate collection systems,

these sections provide that:

     0  New units and lateral  expansions and replacements of

       existing units at hazardous waste landfills and surface

       impoundments must be double lined and have leachate

       collection systems above (in the case of landfills) and

       between the liners;

     0  New units and lateral  expansions and replacements of

       existing units at interim status waste piles must meet

       the requirements for single liners and leachate collection

       systems provided in  the Agency's current permitting

       regulations for new  waste piles.

     0  All hazardous waste  facility permits issued after

       November 8,  1984,  must ensure that these requirements are

       imposed on  the appropriate units;

     °  Affected interim status units must meet these requirements

       by  May  8,  1985;


                                              U-.S.               •
                                              Region

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        Owners or operators of interim status units subject to




        the double liner requirements must notify EPA or the




        State  of their intent  to receive waste into one of the




        affected units sixty days before the waste is received;  and




        Double liner systems installed in good faith compliance




        with Agency regulations  and  guidance during interim status




        will not have to be replaced at the  time  of permitting



        unless they are  leaking.




Scope of this Guidance




     The purpose of this document,  and the  associated technical




guidance documents,  is  to  provide further interpretation of the




minimum technological requirements  found in Sections 3004(o)  and




3015 of the new statute  as  they  relate to liners  and leachate




collection  systems.  As  comments  are  received on  this guidance




document, they will  be  used to revise  the guidance as appropriate




and to  establish  a  sound basis  for  future rulemaking.




     This RCRA  statutory interpretation  describes  the following



provisions of HSWA:




     0 Applicability of the minimum technological  requirements;




     0 Notification requirements  for interim  status  facilities;



     0 Acceptable liner systems  (detailed descriptions  are  contained




       in the  two attached  technical guidance  documents);




     0 A description of the requirements for  demonstrating  good




       faith compliance with the  double  liner  system requirements;




       and




     0 Variances from the double  liner system  requirements.

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      (Note:  The minimum technological requirements are also
      imposed on existing interim status surface impoundments
      under Section 3005(j) of HSWA.  Section 3005(j) provides
      that existing interim status surface impoundments shall
      not receive,  store, or treat hazardous waste after
      November 8, 1988,  unless such impoundments comply with
      the double liner and leachate collection system requirements
      of §3004(o)(1)(A).   A number of variances to the minimum
      technological requirements are also contained in Section
      3005(j) for existing interim status surface impoundments.
      The Section 3005(j) requirements, including the multiple
      variances,  will be  addressed in upcoming guidance to be
      issued by  EPA.   However,  the attachment to this current
      guidance,  entitled  "Minimum Technology Guidance on Double
      Liner Systems for Landfills and Surface Impoundments—
      Design, Construction,  and Operation" should be used for
      the installation of double liner systems at existing
      interim status  surface impoundments that do not qualify
      for one of  the  Section 3005(j) variances.   Although this
      current guidance makes no further mention of the Section
      3005(j) requirements,  it  is important to note that existing
      interim status  surface impoundment units,  although referred
      to herein  as  exempt from  the double liner system requirements
      of Sections 3004(o) and 3015,  may or may not be exempt from
      the double  liner requirements  imposed by Section 3005(j).)

Applicability of the  Minimum Technological Requirements

A.   Interim Status Units

      Section 3015  of  RCRA,  as  amended by HSWA,  imposes minimum

technological requirements  on  certain interim status waste piles

(single  liner system), and  on  certain interim status landfills

and  surface  impoundments (double liner system).   EPA believes

that  the  applicability of  the  minimum technological requirements

should be determined  with reference to the date  of enactment of

HSWA, November 8,  1984.  The requirements  apply  during interim

status to any new  unit,  replacement of an  existing unit,  or

lateral expansion  of  an  existing unit that first receives waste

after November 8,  1984.  Such  a  unit  or expansion must comply

with the minimum technological requirements  with respect  to waste

received after May 8, 1985.

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      In order for a unit or portion of a unit to be exempted




 from the minimum technological requirements,  i.e.,  to be considered




 an "existing unit" rather than a new unit,  replacement,  or lateral



 expansion,  the unit must already have received waste as  of




 November 8,  1984.   In addition,  the area must have  been




 "operational" as of November 8,  1984.   That is,  the area must




 have been constructed by that date  in accordance with Federal,




 State,  and  local requirements,  including licenses and permits.




 If for  some  reason an entire unit was not operational on that




 date (for example,  a required liner,  leachate collection system,




 or berm had  not yet been completely installed or constructed),




 only the portion of the  unit that was  constructed in compliance




 with Federal,  State,  and local  requirements as of November 8,




 1984, will be exempt from the new requirements.   In order to




 determine whether  an area  is within the  boundaries  of the unit,




 available physical  evidence  (e.g.,  berms, excavation,  or other




 construction)  may  indicate where  the  boundaries  are located.




 Other objective  information  (e.g.,  operating  records or  the Part




 A),  if available, may  also be used  to  identify the  boundaries of




 the  unit.




     Any  new  unit or replacement  or lateral expansion of an existing




 unit that first  receives waste after November  8,  1985, is subject




 to the new requirements.  If  such a unit still receives  hazardous




waste after May  &,  1985, the  minimum  technological  requirements




must be  in place on  that date.




     For  interim status  facilities, several options  are  available




 for a new unit or replacement or  lateral expansion  of an existing




unit:

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      (1) If the owner or operator wishes to continue using a




 unit after May 8, 1985, the entire unit could be lined in accordance




 with the new requirements;   if waste were placed in the unit between




 November 8, 1984, and May 8,  1985, this option would require the




 retrofitting of the areas that received the waste so that these




 areas would meet the minimum technological requirements;  or




      (2) The owner or operator may be able to restructure a unit




 that has received waste between November 8,  1984,  and May 8,




 1985,  by creating a barrier between the area that contains waste




 and any empty area (e.g., construction of a berm within a landfill




 trench).  The area that contains waste could not receive  additional




 waste after May 8,  1985 (unless it were retrofitted to meet the




 minimum technological requirements).   The empty area would constitute




 a  new unit  that can receive waste after May 8,  1985,  if it complies




 with  the minimum technological requirements;  or




      (3)  If the owner or operator stops receiving hazardous waste




 in  the  unit on  or before May 8,  1985,  the unit  need not comply




 with  the minimum technological requirements.   In other words,




 Section  3015  does not  impose any new  requirements  on  a new interim



 status  unit or  replacement  or  lateral  expansion that  first receives



 waste after November  8,  1984,  but ceases  to  receive waste by




 May 8,  1985.




 B.  Permitted Units




     Section 3004(o) of  RCRA,  as  amended  by  HSWA,  requires landfills




and surface impoundments  to comply with the  minimum technological




requirements at  the time  of permit  issuance.  This  provision




mandates a  double liner  system  for any  new unit or  replacement




or lateral expansion of  an  existing unit  that  first receives

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waste after the date of permit  issuance.  The requirements must




be  included in any permit  issued after November 8,  1984.




     Although both permitted and interim status landfills and




surface  impoundments must  comply with the same double  liner




requirements, there are distinctions between the permitting and




interim  status requirements.  Compliance with the minimum




technological requirements through the permitting process is




subject  to more stringent  EPA supervision than compliance during




interim  status.  In addition, unlike the interim status provision,




which gives facilities until May 8, 1985, to comply, the permitting




requirements are effective as of the date of enactment of HSWA.




All permits issued after November 8, 1984, must contain the new




requirements.




C.  Issues in Common to Both Interim Status and Permitted Units




     Existing units, as noted above, are not affected by the




requirements of Sections 3004(o) and 3015.  Any portion of a




landfill or surface impoundment that was operational on



November 8, 1984,  and already contained at least some waste as




of that date, qualifies as an existing unit under the new law:




it is an existing unit under Section 3015 (interim  status) because



it received waste and was operational before the date of enactment,




and it is also an existing unit under Section 3004(o)(l)




(permitting) because it received waste before permit issuance.




Therefore,  the entire unit is exempt from the minimum technological




requirements.  EPA's current regulations do require the lining




of partial units at permit issuance:  §264.221(a) (for surface




impoundments), §264.251(a) (for waste piles), and §264.301(a)

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 (for landfills)  require the portions of units not covered with



 waste at permit  issuance to install a single  liner (with a leachate



 collection system above the liner,  in the  case of a landfill or




 waste pile).   This means that even if a landfill or surface




 impounduent unit  is exempt  from the new double liner standards,




 any  portion of the unit not covered with waste at permit issuance




 is still subject  to EPA's current  single liner standards.   Hence,




 in this  instance,  EPA's current standards  have not been superseded-




 by HSWA.   (For technical guidance  on EPA's current single liner




 standards,  see the attached technical guidance entitled:   "Minimum




 Technology Guidance on  Single Liner Systems for Waste Piles,




 Landfills,  and Surface  Impoundments—Design,  Construction,  and




 Operation.")




      In  summary,   the combined effect of Sections 3004(o)(1)(A)




 and  3015  is to require  any  landfill,  surface  impoundment,  or




 waste pile  unit,   replacement,  or lateral expansion that first




 receives waste after November 8, 1984,  to  comply with the  minimum




 technological  requirements  after May 8,  1985  (if such unit or




 replacement or lateral  expansion is  still  receiving hazardous



 waste after that  date),  or  at permit issuance,  whichever occurs




 first.  Landfills  and surface impoundment  units  that install




 double liners  and  leachate  collection systems  in good faith




during interim status cannot  be  required to retrofit at the  time




of first permitting unless  there is  reason  to  believe that  the




 liner is leaking.  Any  landfill or  surface  impoundment unit  that




received waste before November  8,  1984,  is  exempt from the  double

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                                 8
liner system requirements but must comply with Agency's current




single liner regulations with respect to portions not covered




with waste at the time of permit issuance.




     Since enactment of the HSWA, the Agency has received numerous




inquiries regarding the applicability of the minimum technological




requirements for liners and leachate collection systems at




hazardous waste landfills, surface impoundments, and waste piles.




The following definitions, questions, and answers address some




of the more critical issues that have been raised.




     (1)  Existing unit




     0 Issues:




          (a)  If berms are constructed after November 8, 1984, to




              allow wastes to be placed higher on an existing




              unit,  are the minimum technological requirements




              applicable?




               - Response:  The  new requirements do not apply if




                 the additional  waste will be placed within the




                 boundaries of the  existing unit (See note below)




                 and if Federal,  State,  or local requirements,




                 including State and  local permits,  applicable to




                 the unit  on November 8,  1984,  would not require




                 the new construction in order to receive wastes.




          (b) Can a  unit that  has already been partially or




             finally capped receive  additional waste without




             complying with the  minimum technological requirements?




              -  Response:   If the  cap effectively isolates




                 the new waste from the waste within the capped

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                 unit, then the area on which the new waste




                 is placed will be a new unit.  (Also, see




                 note below.)




NOTE  (applicable to (a) and (b) above):




      If the plan, permit, etc., specifies any final elevation




or maximum capacity of the unit, the elevation or capacity




limitation will restrict the maximum allowable height of the




existing unit.  If no final elevation or maximum capacity of the




unit  is specified in operating records, closure plans, State




permits, etc., additional waste can be placed on the area if the




area  is operational.   However,  the additional placement of waste




on a unit must also consider the slope of the final cover at




closure.




          (c)  If a unit qualifies  as an "existing unit" and had




              a very thin layer of hazardous waste placed through-




              out the  unit prior to November 8,  1984,  is the




              entire unit exempt from the minimum technological




              requirements?




               - Response:   One of the criteria for a unit to



                 qualify  as  an  existing unit is  that waste



                 must  have been placed in some part of the unit




                 prior to November 8,  1984.   Therefore,  the unit




                 meets the criterion of having received waste




                 prior to November 8,  1984.  (Because the entire




                 unit  is  covered with waste,  the unit will be




                 exempt from the single liner requirements at




                 permitting.)

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(2)  Permitted unit




     0 Issue:




          Does a unit that received a RCRA permit prior to




          November 8,  1984,  have to meet the minimum technological



          requirements?




               - Response:   As long as the unit was  permitted




                 prior to November 8,  1984,  even if  it has not




                 been constructed,  it is not subject to the




                 minimum technological requirements.



(3)  Replacement unit




     0  Definition:




          Consistent with the  legislative history of HSWA,




          replacement  of a unit occurs when (a)  the  unit is




          taken out  of service (i.e.,  the unit  has stopped




          receiving  waste or the "normal" rate  of waste receipt




          is  significantly decreased),  (b)  all  or substantially




          all  of  the waste is  removed,  and  (c)  the unit is reused.



     0  Issues:




          a)  Is  the  removal of all  or  substantially  all waste




             from a  surface impoundment or  waste pile for  the



            purpose of  inspecting  the  liner or  base  a replacement?




               -  Response:  This will  be a  replacement unit if




                 wastes  are again placed in the  unit.




          b)  If wastes are removed  from a portion of  a waste




            pile, either in the normal operation of  the pile,




            to facilitate inspection  of the base under that




            portion,  or  as part of a  closure activity,  while

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                       11
    the  remainder  of  the waste pile  continues  to  receive




    waste  at  the normal rate, is  this a  replacement?



      -  Response:   The key  criterion in  this case  is




        whether the unit has been taken  out of service.




        Since  the  normal flow of  waste to the unit has




        not ceased, this is not a replacement.




 c)  Is the removal  of all or substantially all the waste




    from a landfill, waste pile,  or  surface impoundment



    for  the purpose of recovering materials, with  the




    residue returned to the unit, a  replacement?




     -  Response:   If the normal  flow of waste to  the




        unit has ceased and all or substantially all




        the waste is gradually removed from the unit




        while processed waste is  being returned to the




        unit, this  is a replacement.  However, if  new




        waste is continually placed  in the unit (i.e.,




        normal waste-receiving operations are continuing)




       while unprocessed waste is being removed for




        recovery and then return  to the unit, this is




       not a replacement.



d) At the time of replacement are there any closure




   requirements?



     - Response:   There are no closure requirements




       such  as public comment or removal of contaminated




       soil  at the time of replacement.   Any contamination




       of  soils at the site,  including contamination from




       activities  prior to the  replacement unit,   will

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                               12
                 be addressed at final closure of the replacement




                 unit.   However,  all applicable criteria for




                 constructing the replacement unit must be adhered




                 to,  including the need for a stable  base that




                 does not contain contaminants that would be




                 incompatible with the replacement unit liner.



(4)  Solid Waste




     0  Issue:




          Can  a new unit or a replacement  or lateral  expansion




          of an existing unit operating under interim status




          that receives  hazardous waste between November 8,




          1984,  and May  8,  1985,  continue  to receive  non-hazardous




          waste after May 8,  1985,  without complying  with the




          minimum technological  requirements?




          - Response:  Since  this is  a new unit,  replacement,  or




           a  lateral expansion,  it can only receive  hazardous




           waste until  May 8.   After that date it can continue




           to receive non-hazardous  waste without complying




           with the  new requirements.   The owner or  operator  of




           all  interim  status units  that  stop receiving hazardous




           waste must comply with the  closure requirements  of




           Subpart G of Part 265.  EPA has issued a  proposed




           rule  providing  that  if  a  unit  is unlikely to receive




           additional hazardous  waste,  the expected  date of




           closure is 30 days after  the date of receipt of  the




           known final  volume of hazardous waste.  See




           50 FR 11090  (March 19,  1985).   EPA policy is that

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                                13
            closure activities  for interim status  units  should




            begin within 30 days of the last  receipt of  hazardous




            waste.



(5)  Conversion of a surface impoundment to a  landfill




     0  Issue:




          Can  the owner/operator of an interim status surface




          impoundment change the facility  process  to become  a




          landfill?  If  the process can be changed,  is the  landfill




          an existing unit,  replacement unit,  or a new unit?




          -  Response:  For  an interim status,  existing unit,




            surface impoundment  to qualify for a change  in process




            to a  landfill it will need to  meet the requirements




            in §270.72(c).   Under this provision,  an owner/




            operator can submit  a revised  Part A application




            (along  with  a justification) for  consideration




            of a  process change.   Only two circumstances can be




            used  to request  a change  of process:




                 (1)  It  is  necessary  to prevent a  threat to  human




                    health  or the  environment because of an



                    emergency situation,  or




                 (2) It  is necessary  to comply with  Federal




                    regulations  or State  or  local laws.




           However, for circumstances  that do allow a process




           change under this very  restrictive requirement,  the




           landfill unit would be  an  existing unit.  However,




           the size of  the  landfill would be  restricted by  the




           existing unit requirements.

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(6)  Liners  and Leachate  Collection  Systems



     0  Issue:




          In a double  liner  system,  must both  liners  and  the




          leachate  collection  sytems extend up the  sidewalls  of




         a landfill or  surface  impoundment  (impoundments have




         only one  leachate  collection  system, which  is between



         the  liners)?




         - Response




               The  Agency interprets Section 3004(o)(1)(A)(i) to




               require that  both liners of the double  liner




               system and the  leachate  collection system  between




               the  liners extend to  any area of the unit  that is




               in contact with the waste.  This interpretation




               of the statutory requirement is consistent with




               the  Agency's  current  regulatory practice regarding




               the  design of double  lined units.  Congress  intended




               that the Agency's existing design standards provide



               the  basis for interpreting the  new minimum techno-




               logical requirements.  In addition, the legislative




              history of HSWA suggests that the leachate collection




               system between the liners should act both  as




               leachate collection and removal system and a leak




              detection system.  These purposes can be achieved




              only if the liners and the leachate collection




              system between the liners cover all surfaces of




              the unit that are in  contact with the wastes.

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                    The HSWA does not specifically require that




               the primary leachate collection system of a landfill




               (the leachate collection system above the top liner)




               extend up the sidewalls.  The legislative history




               of HSWA also does not address this issue.  EPA's




               past policy, as stated in guidance, has been to




               allow the installation of a primary leachate




               collection system on the base and only partially




               up the sides of a landfill in some cases, depending




               on site-specific circumstances.   Although the




               Agency believes that the statute has done nothing




               to alter this  policy,  we believe that,  in general,




               it is  more protective to install primary leachate




               collection systems on both the base and sidewalls,




               and we encourage such designs.  Such a design




               allows  leachate to drain to the  surnp faster and




               minimizes  ponding of leachate within the waste on




               the sidewalls  of the top liner.




(7)  Interim Status Waste  Piles



     0  Issue:




         What  are the  liner  and ground-water monitoring require-




         ments at interim  status waste  piles?




         -  Response:




              A.   Existing units:




                   0 Subject  to current  regulations promulgated




                     under Part 265.




                   0 Ground-water monitoring not  required.

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     0 If leachate or run-off from the pile




       is a hazardous waste, then either:




          a) The pile must have a single




             impermeable liner with leachate




             collection; or




          b) The pile must be protected from




             precipitation and run-on and no free




             liquids may be placed in the pile.




B.  New units,  replacements, and lateral expansions:




    0 Subject to requirements for a single liner




      with leachate collection and removal under




      §264.251(a).




    0 Variances from single-liner requirements




      are available if:




         a)  The waste pile is in a structure so




            that neither run-off nor leachate




            is  generated (§264.250(c));  or



         b)  The owner or operator shows  that




            alternate design and operating practices,



            together with location characteristics,




            will prevent the migration of hazardous




            constituents into the ground water or




            surface water at any future  time




            (§264.251(b)).




    0  Ground-water  monitoring is not required.

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(8)  Monofills
       Issue:




          What  requirements  must a landfill  or  surface  impoundment




          meet  to qualify  as a  monofill  and  be  eligible for  a




          waiver from the  minimum technological requirements?




          -  Response:




               The unit  must meet the  requirements  of  (A),(B),




               and  (C):




                    (A)  Contain only hazardous  wastes  from




                        foundry furnace  emission controls  or




                        metal casting  molding sand;




                    (B)  The  wastes  must  not  contain constituents




                        that would  render the wastes hazardous




                        for  reasons other than  Extraction




                        Procedure  (EP) toxicity; and




                    (C)  Meet the  requirements of (1) or  (2):




                        (1) the unit  must (a)  have at  least one




                            liner, for which there is  no




                            evidence  that such liner is leaking,



                            (b) be located more than one-quarter




                            mile  (a one-quarter mile radius




                            hemisphere drawn under and around




                            the unit) from an  underground source




                            of drinking water,  and (c) be in




                            compliance with generally applicable




                            ground water monitoring requirements




                            for permitted units; or

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                                 18
                          (2) The  owner/operator  demonstrates




                             that the  unit  is  located,  designed,




                             and  operated such that hazardous




                             constituents will not migrate  into




                             ground water or surface water  at




                             any  future time.




Notification Requirements  for  Interim  Status Facilities




A.  Overview




     Section 3015(b)(2) of HSWA requires the owner or  operator




of an interim status  landfill  or  surface impoundment to notify




the Administrator at  least 60  days prior to receiving  waste at a




new unit, replacement of an existing unit, or  lateral  expansion




of an existing unit.  However, the statute does  not specify the




content of the notice.  The Agency believes that a brief




notification will be  sufficient because the Regions and States




already have good information  about most of the  facilities  that




will be making changes during  interim  status.  Further,  we  do




not foresee problems  in obtaining additional information, if




necessary, through field inspections,  Part B reviews,  or through




the provisions of §270.72  (changes during interim status) that




require a revised Part A permit application prior to an increase




in the design capacity of processes used at a  facility.




B.  Requirements



     The Agency will, therefore,  consider that the owner or




operator has complied with the notification requirement of




HSWA if he submits to the Agency:  (1)  the EPA  Identification




Number for the facility; (2) an indication of  whether  the proposed

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                                 19
 change is for a new unit or replacement or lateral expansion of




 an existing unit; (3) the initial date waste will be received at




 the unit(s) or lateral expansion(s); and (4) a statement signed




 and dated by a company officer that the information provided




 under (1),(2), and (3) is accurate.




 C.  Authorized State



      All requirements of HSWA, including notification requirements




 associated with the minimum technological provisions, are effective




 immediately in authorized States as well as unauthorized States.




 No States are currently authorized for implementation of the




 minimum technological requirements.  Until such time as States




 are authorized (for interim or final authorization for minimum




 technological requirements), all notification should be sent to




 the appropriate EPA Regional Office.  Applicants who are uncertain




 as to the status of their State should contact the EPA Regional




 Office.




 Acceptable Liner Systems




 A.  Surface Impoundments and Landfills




      Section 3004(o)(5)(B)  allows the use of a particular type of




 liner design until EPA issues regulations implementing the double



 liner requirements in §3004(o).  The Agency has identified two




 additional designs, or more  accurately performance requirements




 for two  designs,  that it believes meet the liner and leachate




 collection system requirements for certain landfills and surface




 impoundments  under §§3004(o)  and 3015.   The Agency will accept




'permit applications and  issue draft permits for facility designs




 that  meet  the  performance-based designs described in this guidance.

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                                20
Whether these designs appear in the final permit will depend




upon the Agency's response to comments on the draft permit.




The two designs are fully described in the attached draft technical




guidance entitled "Minimum Technology Guidance on Double Liner



Systems for Landfills and Surface Impoundments—Design, Construction,




and Operation."  The Agency will accept convincing demonstrations




of equivalency of performance to the specifications in this




guidance as adequate demonstration of compliance with RCRA Section




3004(o)(l)(A)(i).



     In addition to the designs in the attached technical guidance,




EPA will accept the design set out in §3004(o)(5)(B).  However,




the Agency has reservations about whether the interim statutory




bottom liner design, i.e., three feet of compacted clay with a




hydraulic conductivity of not greater than 1X10~7 centimeters




per second,  will meet the bottom liner performance criteria of




that section in most cases.  The specified performance standard




requires that the bottom liner prevent migration of any constituent



through it during the operating period, including any post-closure




monitoring period.  To meet this standard, a bottom liner of




compacted clay or other natural soil material must be thick




enough and low enough in permeability to prevent the migration




of any constituent through the liner during the stated period.




The breakthrough time for constituents, in most cases, will be




governed by unsaturated liquid flow through the liner.  EPA is




studying the breakthrough of constituents through compacted soil




liners.  There is currently, however, no field-verified method




for determining either breakthrough or the associated liner

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                                 21
 thickness requirements.  EPA believes that the interim design




 (i.e., a three-foot thick compacted liner with a saturated hydraulic




 conductivity of 1X10~^ cm/sec) will result in a breakthrough




 time substantially shorter than the operating period in most




 cases, as explained more fully in the attached technical guidance.




 EPA does not discourage rigorous demonstrations of liner designs.




 The Agency has,  however, strong reservations concerning the




 likelihood that such a design is either economically or technically




 feasible in most cases.  However,  because §3004(o)(5)(B) authorizes




 the use  of a lower liner constructed of a 3-foot thick compacted




 soil liner with  a  saturated hydraulic conductivity of  1X10"^




 cm/sec,  owners  and operators may use this design until such time




 as  the effective date  of regulations or until this  guidance is




 finalized.




 B.   Waste  Piles




      Section 3015(a) of HSWA requires  the owner or  operator




 of  new units, replacements,  and  lateral expansions  of  interim




 status waste piles  to  meet  the  existing Agency requirements for




 single liners and  leachate  collection  systems for new  waste




piles  under  Part 264.   These  single  liner system requirements



 are  contained in §264.251.




     The attached technical  guidance  entitled "Minimum Technology




Guidance on  Single Liner Systems for Waste Piles, Landfills,  and




Surface Impoundments--Design, Construction,  and  Operation"




updates the Agency's previously  issued  single liner  system  guidance.




It contains  single liner system design,  construction,  and operation




specifications that the Agency believes  are  acceptable  for  meeting

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                                 22
 the  requirements  of §264.251.   (In  addition  to waste piles,  the




 attached  single liner system guidance  also addresses landfills




 and  surface  impoundments  because  certain portions  of existing




 landfills and  surface impoundments,  although exempt  from the




 double  liner requirements of HSWA,  are required by Agency regulations




 to be single lined  at permitting.)




 C.   Construction  Quality  Assurance  for Liner Systems




     To assure, to  a  reasonable degree of  certainty,  that a




 completed liner system meets or exceeds all  required design




 criteria,  plans,  and  specifications, a construction  quality




 assurance (CQA) program is necessary.   CQA is  included as part




 of the  attached technical guidance  to  detect deviations from the




 design, caused by error or negligence  on the part  of the construction




 contractor,  and to  provide the suitable corrective measures




 before  wastes are placed  in  the unit.   A CQA guidance document




 is currently being  developed.




 Good Faith Compliance  with Guidance  and Regulations



     HSWA requires  that an owner  or  operator of an interim



 status  landfill or  surface impoundment facility, who builds  a




 new unit,   lateral expansion  of an existing unit, or  replacement




 of an existing unit,  comply  with  the minimum technological




 requirements of §3004(o)  with respect  to waste received




 after May 8, 1985.  Before a permit  is  issued,  the owner or




 operator  of  the facility  is  required to show that  the liner  and




 leachate  collection systems  installed  during interim status  have




been installed in "good faith compliance"  with EPA's regulations




 and guidance documents.   If  the system has been installed in

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                                 23
 good  faith compliance, then the Administrator  can not require  liner

 retrofitting at  the  time  of permit  issuance unless he has

 reason to believe that the liner is  leaking.

      The owner and operator will meet his burden of demonstrating

 good  faith compliance if  he complies with the  notification

 requirements discussed earlier in this guidance and makes the

 following two demonstrations.  The owner and operator should:

      0 present evidence to the Agency that all the appropriate

       units were lined;  and

      0 present evidence that the liner and leachate collection

       systems were designed and installed in  accordance with

       the Agency's regulations and with the double liner guidance

       described in the attachment to this document or any

       additional guidance provided on Section 3004(o)(5)(B).

The information for these demonstrations should be kept at the

facility.  The required records for making a good faith demonstration

are described below.

A.  Demonstrating that all appropriate units have been double lined

     According to §265.73(b)(1) and  (2) (and §265.309 for

landfills),  the owner or operator must keep written operating

records at his facility that contain:

     1) a description and the quantity of each hazardous waste
        received, and the method(s)  and date(s) of its treatment,
        storage,  or disposal at the facility ....

     2) the location  of each hazardous waste within the facility
        and the quantity at each location.   For disposal facilities
        (emphasis added)  the location and quantity of each hazardous
        waste must be recorded on a map or diagram of each cell or
        disposal area.  .  . .

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                                 24
      The Agency will  request the submission of the facility's




 operating records when the permit application is submitted.




 Compliance with these two recordkeeping requirements discussed



 above may provide sufficient information for the owner or operator




 to demonstrate where waste was placed on the facility as of




 November 8,  1984, and May 8, 1985.  The owner or operator should




 clearly distinguish between "existing units" and new units,




 lateral expansions of existing units, or replacement units.




      In addition to the information found in the operating




 records, the Agency will look to the information submitted in




 the facility's Part B application to be assured that the proper




 units were double lined.  EPA will receive all the facilities'




 Part  B applications by November 8, 1985.




      Furthermore, the Agency will look to the information gathered




 by our field inspectors.  EPA may elect to conduct an inspection




 after the owner or operator notifies the Agency 60 days prior to




 receipt of waste at a new unit, replacement of an existing unit,



 or lateral expansion of an existing unit.  The inspector will




 review the operating records and visually inspect the site to




 determine if the operating records accurately detail the boundaries




 of the existing units and the units that are being double lined.




     The owner or operator should bear in mind the importance of




keeping accurate and complete operating records to demonstrate that




 the proper units were double lined during interim status.  The




permit writer will look to the owner or operator to make this




demonstration at the time of permit review, which may be some




time after the units have been lined and in use.  The permit

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                                 25
 writer will depend on the operating records,  Part B application,

 and inspection records to decide whether an owner or operator

 double lined the proper units.

 B.   Demonstrating that the liner and leachate collection system(s)
     were designed and installed in accordance with the Agency's
     regulations and guidance

      The Agency has interpreted HSWA to mean  that an owner or

 operator who demonstrates that  he followed the guidance in this

 document and its attachments, or the terms of §3004(o)(5)(B),

 will be considered to have acted in good faith.   The owner or

 operator can demonstrate  that the liners and  leachate collection

 systems were designed and installed in good faith by showing

 that the design conforms  to the guidance,  or  §3004(o)(5)(3),

 and an  adequate construction quality assurance (CQA) plan  was

 prepared and followed.  This CQA plan should  be kept at the

 facility.   The  procedure  for developing a  CQA plan is  specified

 in  the  attached technical guidance.   Additional guidance will  be

 provided in Construction  Quality Assurance for Land Based  Hazardous

 Waste Facilities,  which will be issued  in  draft form in June

 1985.   The  CQA  plan will  be  reviewed  during the site inspection

 and will be  the  chief means  for the permit writer to determine

 whether  the  owner  or operator followed  the liner  guidance  in

 designing and installing  the double  liner  system.

     Owners  and operators of facilities  that  have already

 installed double lined units before the  issuance  of this guidance

must show that their liners meet  the  requirements of HSWA  §3004(o).

To meet this requirement, owners  and  operators may use  the

statutory interim  design  in  §3004(o)(5)(B), or may show that

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                                 26
 the design complies with §3004(o)(1)(A)(i),  which EPA believes




 requires a design that protects human health and the environment.




      Some owners or operators who plan to install a double liner




 system may choose to deviate from the design in §3004(o)(5)(B)




 or the designs in this liner guidance.  Alternate designs may be




 installed if they meet the performance standards embodied in the




 double liner system design in this  guidance.  Owners or operators




 should confer with the Agency during the design and construction




 of the alternate system in order for EPA to  ascertain whether




 the system will meet the double  liner performance standards.   As




 a  result,  these facilities will  be  able to more easily demonstrate




 to the Agency during the Part B  review that  their alternate




 design meets  the performance standards in this  guidance.




 Variances  from the Double Liner  System Requirements




     RCRA  §3004(o)(2)  and (3)  provides authority to the Administrator




 to waive the  double liner requirements in two situations.   In




 one case,  a waiver may be allowed if the  owner  or operator demon-




 strates  that  alternative design  and  operating practices, together




 with location  characteristics, will  prevent  the migration of  any




 hazardous  constituents into the  ground water or surface water at




 least  as effectively as  double liner and  leachate collection




 systems specified  in this  guidance.   The  second waiver applies




 to  monofills receiving only wastes from foundry furnace emission




 controls or metal  casting  molding sand that  are riot hazardous




wastes for reasons  other  than  Extraction  Procedure toxicity.




     Owners or  operators  applying for  a waiver  for a permitted




unit should submit  appropriate information in their Part B

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                                 27
 permit application.    Until EPA develops specific procedures


 for interim status purposes,  owners and operators seeking a


 variance for an interim status unit should seek approval on a


 case-by-case basis from the EPA Regional Administrator before


 designing the unit.


      This guidance should be  used in preparing and evaluating


 waiver requests regarding alternate design and operating practices


 In addition,  the Agency is developing more detailed guidance on


 alternate design and  operating practices.   We  expect to make


 this  additional guidance available in 1986.  No specific guidance


 is planned for the monofill waiver.


      In order to evaluate any waiver request,  the objectives of


 the liner and leachate  collection systems  must be established.


 These  objectives are:  (1)  to  maximize the  removal of leachate


 containing hazardous  constituents during the active life and


 through any post-closure monitoring  period and (2)  in combination
             *>

 with the  final  cover  system,  to minimize the escape of hazardous


 constituents  from the unit in the long-term future.


     Until  regulations  are developed,  the  design specified in


 §3004(o)(5)(B)  provides  the standard against which alternate


 designs should  be  compared.   Three factors—design,  operation,


 and location—determine  whether an alternate design can meet the


waiver  criteria.   These  factors  must be used recognizing the


 characteristics  of the  land disposal process and how migration


 can be  expected  to occur.   Hazardous constituents  that escape


the unit can  be  expected to migrate  if  they are liquids or if


they are dissolved or suspended  in liquids.  Therefore,  surface

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                                28
impoundments, because they are storage or disposal units  for




liquids, are more difficult to qualify for the waiver.  Landfills,




on the other hand, may be more likely to qualify for the  waiver




if the owner or operator can demonstrate that the facility




adequately manages liquids.



     Adequate liquids management can be demonstrated by showing




that liquids are minimized at the  facility.  First, the landfill




should be kept as dry as possible.  This includes not  accepting




bulk liquid wastes for disposal, controlling surface run-on so




that rainfall does not add excessive moisture, and keeping




the disposal site above the ground-water table.  There are  other




design and operating features that can be used to minimize  moisture,




including building the landfill under roof and rapid removal  of




any incident precipitation.  The goal of these liquids management




activities is to minimize the formation of leachate during  the




life of the facility.  With little or no leachate, which  is the




driving force to cause migration of hazardous constituents,  the




waiver may be granted.  This waiver would not relieve  the owner




or operator from any responsibility to construct and maintain a




proper final cover.



     The demonstration that there  is no likelihood of  significant




amounts of leachate may also be made based on climate. Certain




areas of the country receive very  small amounts of rainfall




annually.  By using calculations or experience gained  at  other




units constructed in the same climate, it may be possible to




demonstrate that little or no leachate is formed.  The waiver




could be granted when such a demonstration is made.  As before,

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                                 29
 this  would  not  affect  the  design  of  a final cover.
      Another  way  to qualify  for the  waiver is to prove that the
 leachate  does not  contain  hazardous  constituents.  This demon-
 stration  requires  specific testing because leachate is presumed
 to  contain  hazardous constituents.   Some hazardous constituents
 may not leach and  may  be eligible for a waiver.  It may also be
 possible  to qualify for a  waiver  by  showing that the wastes are
 treated prior to disposal  so that they do not leach.  This
 demonstration can  be made  based on the non-leaching characteristics
 of  the waste  alone or  in combination with the facility location
 (e.g., the  facility is located in a  very low rainfall  area).
      A facility located in an area that is capable of  attenuating
 all the hazardous  constituents before they reach ground water
 or surface water may also qualify for a waiver.  This  demonstration
 may be possible, under some circumstances, for inorganic hazardous
 constituents,  especially heavy metals.  It is less likely that a
 successful demonstration could be made for most organic hazardous
 constituents.
      In general, EPA expects  that waiver demonstrations will be
 difficult  to make.  The owner or operator will  be expected to
make a comprehensive demonstration that  his alternative design
and operating  practices,  together with location characteristics,
are as effective as the double liner and leachate collection
systems specified  in this  guidance.

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