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FAXBACK 13184

9489.1988(01)

THERMAL TREATMENT UNITS, SCOPE OF SUBPART X

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

MAY 18 1988

MEMORANDUM

SUBJECT: Morton Thiokol Thermal Treatment Units

FROM: Sylvia K. Lowrance, Director
Office of Solid Waste (WH-562A)

TO: Robert L. Duprey, Director
Hazardous Waste Management Division
Region VIII

This is in response to your April 13, 1988 memorandum
requesting a clarification concerning the scope of Subpart X as
related to thermal treatment, and the interaction of Subpart X
standards and the land ban restrictions for mixed solvents. I
would like to address your concerns in the same order as
discussed in your memorandum.

What is the scope of units comprising Subpart X ?

Subpart X covers miscellaneous units not regulated under
the standards for specific types of treatment, storage, and
disposal units in Part 264, Subparts I through O, or Part 146.
Likewise, Subpart X will not supersede or replace any specific
restrictions on activities contained in another subpart of the
regulations, nor provide a vehicle for escaping from these
restrictions.

What is the scope of units comprising Subpart X?

Subpart X covers miscellaneous units not regulated under
the standards for specific types of treatment, storage, and
disposal units in Part 264, Subparts I through O, or Part 146.
Like wise, Subpart X will no supersede or replace any specific
restriction on activities contained in another subpart of the
regulations, nor provide a vehicle for escaping from these
restrictions.

Specifically, are the units which are operated by placing the
liquid wastewater containing reactive wastes into the pit or
surface impoundment and then allowing evaporation and
percolation of the liquid prior to burning, regulated as
thermal treatment units, surface impoundments, or both?

The ten units which are operated by (1) depositing liquid
wastewater, containing varying amounts of reactive wastes,
directly in unlined pits, (2) allowing the liquid to
evaporate/percolate, and then (3) igniting the residue, are
surface impoundments. The described pits are specifically
included in the definition of surface impoundment in 40 CFR
260.10 (that is, aeration pits). Being such, the units will
require permits based an Part 264 Subpart K. 40 CFR 264.220
states that Subpart K applies to facilities that use surface
impoundments to treat, store, or dispose of hazardous waste.
However, the permit applicant can be required to supply
additional information as required in 40 CFR 270.23 (i.e., for
miscellaneous units) if the Subpart K standards do not provide
adequate protection for human health and the environment. For
example, the Regional Administrator may write permit conditions
based on the Subpart X standards which would protect the air or
surrounding soils during the burning phase of the treatment
process.

What land disposal deadlines and restrictions are applicable to
the units as defined by the answer to the above question? Must
the units meet the November 8, 1988, retrofit deadline or
close?

The Agency has concluded that open burning/open detonation
(OB/OD) of waste explosives in a Part 265, Subpart Q, or a Part
264, Subpart X, OB/OD unit does not constitute land disposal
because it is treatment, not disposal (52 FR 46592). This is
true except in cases where the residuals from the OB/OD
operation remain a hazardous waste. Therefore, OB/OD
activities are not automatically subject to the land disposal
restrictions.

As we indicated above, the treatment pits are properly
classified as surface impoundments; therefore, all land
disposal deadlines and restrictions and the surface impoundment
retrofit deadline remain applicable. Furthermore; a unit is an
OB/OD unit under Parts 264 and 265 when it is not a surface,
impoundment and when it open burns/detonates waste explosives.
As mentioned in 265.382, non-military waste explosives can be
open burned/detonated only when they have the potential to
detonate. According to the information we have on Morton
Thiokol's treatment pits or impoundments, wastewater that does
not have the potential to detonate is placed in a pit and is
treated by dewatering and subsequent burning.

Does the burning of solvents which are contaminated with
reactive material constitute a violation of 40 CFR 265,382
hazardous waste open burning prohibition? Does the solvent
mixed waste meet the Subpart X burning requirements?

The open burning of solvents is strictly prohibited. Only
waste explosives that have the potential to detonate, and bulk
military propellants which cannot be safely disposed of through
other modes of treatment, can be open burned in a Part 264
Subpart X, or Part 265, Subpart Q, unit. (See 40 CFR 265.382)
If the waste solvent is a waste explosive that has the
potential to detonate, then it can be open burned provided that
the unit fits the appropriate criteria. The descriptive
information on unit #11 is not definitive but we suspect that
"trough" referred to in your memorandum may be a tank, and
therefore, also does not qualify as a 264, Subpart X, or Part
265, Subpart Q unit.

More information is needed for us to make a final
determination on the potential to detonate (e.g., exact
concentration of explosive or ratio of materials is not known
nor is its fulfillment of the definition of "detonate" in
265.382 fully known). However, we do not think the open burning
of the 1,1,1-trichloroethane or any other solvent will prove to
be proper when this information is provided.

What land ban requirements are applicable to the solvent
wastes? Can the solvents be opened burned and do the land ban
requirements apply to the solvents?

Because disposal of the solvents is not likely to qualify
as OB/OD in a Subpart X or Subpart Q unit, all of the land
disposal restriction requirements, including those at 40 CFR
268.4, would appear to be applicable to the management of
solvents in the situation you outlined. In such event, the
solvents cannot be open burned.

If you have a question regarding these clarifications or
would like to discuss the issues in more detail, please contact
Chester Oszman (382-4499).

cc: Hazardous Waste Branch Chiefs, Regions I-X
Lisa Reed, Region VIII
Fred Chanania, OGC
Kent Anderson, OSW
Chester Oszman, OSW