vvEPA
               United States
               Environmental Protection
               Agency
             Office of
             Solid Waste and
             Emergency Response
DIRECTIVE NUMBER:
               9476.02(83)
                     Interpretation of Closure and Post-Closure Re-
                     quirements Regarding Hazardous Waste Treatment,
                     Storage and Disposal Facilities
                APPROVAL DATE:  i'11'83

                EFFECTIVE DATE:  i-11"83

                ORIGINATING OFFICE: office of Solid Waste

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PARTS 264 AND 265  SUBPART G - CLOSURE/POST-CLOSURE            'TOG:   9^76.02(83)


Key Words:    Closure, Final Cover, Liquid Wastes, Pose-Closure

Regulations:  40 CFR Parts 264, 265, HSWA.201(c)

Subject:      Interpretation of Closure and Post-Closure Requirements Regarding
              Hazardous Waste Treatment, Storage and Disposal Facilities

Addressee:    Dr. Reva Rubenstein, Director, Institute of Chemical Wastes
              Management Association, National Solid Wastes Management Associa-
              tion, 1120 Connecticut Avenue, N.W., Washington,  D.C.  20036

Originator:  -John H. Skinner, Acting Director, Office of Solid Waste

Source Doc:  -#9476.02(83)    •    '''"'.'

Date: '    •'  '  1-11-83 .

Summary:

     Recontouring the final cover material and adjusting inplace waste in the.
same unit as required to maintain the function of the final cover (as a result
of subsidence and settlement) does not constitute receipt of hazardous waste
after July 26,  1982 (HSWA).  These actions must be approved as  part of each
facilityrs closure plan by the Regional Administrator.  Modifications can be
made with Agency approval.

     Controlled irrigation of the vegetative cover is allowed in order to
establish vegetation during the closure period or to maintain it during pro-
longed dry spells in the post-closure period.  However, to provide long-term
minimization of migration of liquids through the closed landfill and to func-
tion with minimum maintenance, the plant species chosen should  be indigenous,
require little  or no additional moisture, and be selected based on anticipated
moisture, light, temperature, elevation, competitive cohabitants, etc.  The
closure and post-closure plans should contain a description of  when and why
irrigation may be necessary.  The placement of bulk liquids in  non-containerized
liquid hazrdous waste, or free liquids contained in hazardous waste, is prohibited
from any landfill after May 8, 1985 (HSWA §§ 201(c)).  In addition, the following
points must be  emphasized:

     o  Any liquid added to sustain vegetation cannot be a hazardous waste.
     o  Liquids may not be injected into the waste after closure.
     o  Liquids are not allowed during closure, after May 1985, including
        leachate recirculation.
     o  The characteristics and purpose of any liquids to be added to the cover
        during or after closure must be specified in the closure or post-closure
        plans and approved by the RA or authorized State.  Such purpose and
        extension must be consistent with the environmental objectives specified
        in Parts 264 and 265.

     Assuming an owner/operator completes the cell in a timely manner (i.e.
within the 180-day closure period), landfills that are currently engaged in
co-disposal of hazardous and non-hazardous wastes could continue to accept
non-hazardous wastes after-July 26, 1982, in order to complete a partially

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Continued from Document 9476.02(83)


filled hazardous waste unit and close pursuant to Part 264 and 265 requirements.
If the closure- cannot be completed within the 180-day closure period, the
owner/operator must apply to have the period extended beyond six months, for a
specified time period [see §§265.113(b) or 264.113(b)] to allow the waste to be
filled until the designed elevation is reached.   This type of closure could be
approved if it provides for a more environmentally sound closure, and not
merely for the economic convenience of the owner/operator.

     Where a surface impoundment receives no more hazardous  wastes after July
26, 1982, but closure has not yet been effected,  the waste may be removed from
the surface impoundment, solidified and placed in the same impoundment to
ensure 'that it •will-bear the weight of the cover.  Assuming that this solidi-
fying material is not a hazardous waste,  EPA does not consider this replacement
of waste (after January 25, 1983) to be "receipt" of hazardous waste which
would constitute a "regulated unit."

     Where multiple hazardous waste trenches will cease to receive hazardous
waste on or before July 26, 1982, and where the  closure plan provides for a
delayed closure of a half-filled trench for the  deposit of solidified hazardous
waste from closed and capped trenches, such placement of solidified hazardous .
waste into the reserved half filled trench, even at the same facility, will be
considered "receipt" of. hazardous waste.   Therefore, the trench will constitute
a "regulated" unit.  This is because the waste is received and disposed of at
the facility unit after July 26, 1982.  Where landfills consist of a series of
trenches which are separately lined, each trench is a separate waste management
unit.  The transfer of hazardous waste from one  unit to another after July 26,
1982, therefore makes the receiving trench or unit a "regulated" unit.

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                             JAN  j I  IS83
Dr. Reva Rubenstein
Director          .-...-
Institute of Chemical waste   ;  ;     .:  . '  .   ...  .........
  Management      •'•'..
National Solid Wastes
  Management Association
1120 Connecticut Avenue, M.W.
Washington, O.C.   20036

Dear Dr. Rubenstein:

     This letter is in response to your letter of December 6,
1982, requesting interpretation of closure and post-closure
requirements regarding land disposal facilities.  I have
responded to your questions in the order presented in your
letter and attachment.

1. . Recontouring the final cover material and/or adjusting
   ~ inplace waste in the same unit as required to maintain the
    function of the final cover as a result of.-subsidence and
    settlement, does not constitute receipt of hazardous waste
    after January 25, 1983.J  These actions must be described
    in each facility's closure and post-closure plans which
    must be approved by the Regional Administrator.  Modifica-
    tions can be made to these plans as- necessary- with Agency
    approval.

2.  The controlled irrigation of the vegetative cover is allowed
    in order to establish vegetation during the closure period
    or to maintain it during prolonged dry spells in the post-
    closure period.   But the regulations require the final cover
    to provide long-terra minimization of migration of liquids
    through the closed landfill (S264.'310(a) (1) ) , and to function
    with minimum maintenance (S264.310(a)(2)).  Thus, the
    guidance documents recommend that the plant species chosen
    be indigenous, require minimal or no additional moisture,
    and be selected based on anticipated moisture, light,
    temperature, elevation, and competitive cohabitants, etc.

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The closure and post-closure plans should contain a descrip-
tion of why and when the irrigation may h*» determined  to
be necessary  (e.g., recommended by local agrononisit to
establish vegetation during- a dry period), the amount  and
frequency of water application, and water balance analysis
showing the effect of the irrigation water on total annual
liquid input through the final cover./

EPA has available two reports that provide technical
information on this subject, entitled "Evaluating Cover
Systems for Solid and Hazardous Waste" sw-867, September
1982, which discusses irrigation of plant cover and other
plant requirements; and (2)."Hydrologic Simulation on
Solid Waste. Disposal Sites". SW-868, September 1982, which
is a computerized water balance model, to evaluate the
probable hydrologic performance of existing or proposed
landfill designs.  Both of the reports are available from
the Government Printing Office^ (SW-367 i« stock No. 055-
000-00228-2 «S4.75, SW-S68 is Stock No. 055-000-00225-8
$36.00).  EPA is currently revising the model for "Hydrologic
Simulation on Solid Waste Disposal sites" to enable its
use in estimating seepage through the liner as well as
through the cover.  The revised model should be available
early in 1983.

Your statement that 40 CPK Parts 264 and 265 prohibit  the
addition of bulk liquids to the waste^ management unit ,1s
not quite accurate.  Bulk liquids^aVe^ 'afrlnfiefl "'i'r "itne' site
is lined and has a leachate collection and "removal system.
Liquids in the leachate collection system must be removed
during operation, closure, and post-closure.  In general,
the addition of liquids into the unit during closure would
be permitted only if by doing so the facility and waste
will be stabilized sooner.  As you know, the objective
during and after closure is to remove liquids and keep them
out.  If liquids are added during closure, the closure period
would need to be extended until the addition stopped.

To further clarify the above explanations I must emphasize
four points*  First, any liquid applied to the final cover
of a landfill to sustain vegetation cannot be a hazardous
waste (e.g., cannot be leachate unless it is no longer a
hazardous waste), cannot harm the vegetation, and cannot
otherwise iapair the integrity of the final coyer (e.g.,
cause increased infiltration because of damage caused  by
pH).  Second, liquids may not be injected into the waste
after closure (e.g., leachate recirculation by injection),
since this is contrary to the post-closure objective of
keeping liquids out.  Third, as stated aoove, liquids
could be allowed during closure, including leachate

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 recirculaiion, id: (a)  there  is  a  liner  and leachate
 collection system, (b)  leachate  is  removed  from the
 leachata collection system, (c)  the addition of liquids	
 serves Jtpjj* njiariJCLa."closure~Te.g. , accelerates subsidence
-end" Ytab ill sat ion P/~ r^JLh.er jyiajT_jnQrely serves as a__cpnveniant
 way to dispose of thjTl'iqu id a, ~anH~T d ) tn e  liquid addition
 ia explained ^aad  "luatitied  in the cl.Qaugg_glan. .Such
    Saure would not be completed _unti_l _recircu^a_tion__c:ea.8e8j	
 Also/ recircuiaTion ot  a~ hazardous  waste (leachate)  after
 Tanuary 26, 1983 vould  make the  unit  a regulated uni£
 subject to tha requirements of Part 264._ I should point
 out that racirculatio'n  of a hazardous waste (leachate)  can
 occur during operation_jn4» would normally be considered an
 operational ra~tF«r than closure  activity.   Closure activities
 are those which _lejid_to_stabflTzation ~o~f~" the unit in a_
'.tinely Bannerafter receipt of wastes has ceased..  Four^b,
'>the./characterist'i'cs and purpose  of  any"TlquldsTo be added^
 Co the land'fill or to the cover  during or after closure.
 must be specified in the closure or post-closure plans  and
 approved by the RA (or  authorized State), including  any
 extension of the closure period.  Such purpose and extension
 must be consistent with the environmental objectives specif-ted
 in Part 264 or 265. __                                       ~~~

 Landfills that are currently  engaged  in  co-disposal  of
 hazardous and non-hazardous wastes  could continue to accept
 non-hazardous wastes after January  25, 1983, in order  to
 complete a partially filled hazardous waste unit and close
 under either 40. CFR Part 265  or  Part  264 requirements.  This
 assumes that the owner or operator  completes the cell  in  a
 timely manner, which generally raeans within the 180  day
 closure period.   I_f the closure  cannot be completed  _w_Lth-in
 the 180 days the owner or operator  must  apply to have  the
 closure period extended beyond" 6 raonths, for a specified
 time period, as pr_oyide<1_ in *0 C?*  265". ir3.ibjL.9T 2S4. ttT(_b) *.
 to allow the waste to be filled  until the designed elevation
 is reached. _ This type of closure could  be  approved  if  it  -
 provides for a more enviroronentally sound closure, and  not'"'
'merely for the economic convenience of the  owner or  operator.
'Each extension will be considered on a case—by-case  basis.
 The regulatory concern  is closing the landfill in as expedient
 a  time as is practical  (i.e., achieving  final contour  and
 final cover) so as to prevent additional rainfall infiltration
 and other environaental exposure.'  Pertinent factors include
 use of earth materials and redesigning the  final contours.
 The Regional Administrator or approved state permitting
 authority could approve a closure plan or modification
 to the closure plan allowing  the unit or cell to be  completed
 with non-hazardous waste after January 25,  1983, and possibly
 extending the closure period  (wore  than  6 months) after
 January 25, 1983 upon such a  showing.  Conditions foe
 accomplishing this would b« in any  approved closure  plan

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    or closura permit (e.g./ ti™* period, final contours, type
    of
    For the situation where a surface impoundment "closes as a
    landfill" before January 25 ,. 1983, I presume you mean no
    rnore hazardous wastes received after January 25, 1983, but
    cloaur® (e.g., dewatering, etc*) has not yet been done.
    The waste will be removed from the surface impoundment,
    solidified and replaced in the sane impoundment, to ensure
    that it will bear the weight of the cover.  BPA do«a not
    consider this replacement of waste after January 25, 1983,
    to b« "recaipt" of hazardous waste which would constitute
    a "regulated unit".   This decision assumes that the
    solidifying rxaterial is not a hazardous waste.

    For your last question you described the case where
    multiple hazardous waste trenches will cea^e to receive
    hazardous waste on or before January 25, 1983, -and where
    the closure plan provides for a delayed closure of a half-
    filled trench for the deposit of solidified hazardous
    waste from closed and capped trenches. - Tr ^""^ral , such
    placement
    trenches into tho reserved half ^-filled ttre-ac&r even at
    the same facility, will b« considered "receipt* of hazardous
    waste such AS to constitute a "regulated" unit.^&scause the
    waste is received and disposed at the facility unTE after
    January 26, 1983_.  I refer you to the July 26, 1982 federal
    Register preamble discussion at 47 PP 32289 which describes
    the concept of a waste management unit.  Where landfills
    consist of a series of trenches which are separately 'lined,
    each trench is a separate waste aanagement unit.  The transfer
    of hazardous waste fron one unit to another after January 26,
    1983 therefore makes the receiving trench or unit a "regulated*
    unit.  _

     As a side note, I should mention that the closure
performance standard for interim status and for permitting
facilities is the same (40 CFR 264.111 and 40 CP3 265.111).
The final cover or cap for landfills closed under Part 264 or
265 standards should be siailar. - Significant Differences in
the design of the cap should result from site specific factors
rather than the type o? permit a facility ha«.  Thus, many of
the above comment 3 apply to both Part 264 and 265 closure
requirements.

     I hope the above explanations help clarify the regulations
for you.  Should you have any further questions with regard to

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how this regulation effects NSW*A members please  contact r*e  or
Pred Lindsay of my staff (382-4756).


                                  Sincerely yours,
                                  John H. Skinner
                                  Acting Director
                                  Office of Solid Waste

cc:   Regions I - X (with incoming)
          Cook .
     Eileen Claussen.
     Joh n Lehna n
     Bruce We<1dle
     Lisa- Friedman
     Mark Greenwood
     Pred Lindaey
     Gene Lucero
     Ken Shuster

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