vvEPA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
DIRECTIVE NUMBER:
>502.01(84)
IITLt. Permitting of Refinery Oily Wastewater Treatment
Ponds
APPROVAL DATE: 12-07-34
EFFECTIVE DATE: i2-o?-84
ORIGINATING OFFICE: office of solid waste
0 FINAL
D DRAFT
STATUS:
[ I
A- Pending OMB approval
B- Pending AA-OSWER approval "
[ - ] ^ C- For review &/or comment . .
[ ] D- In development or circulating
REFERENCE (other documents): headquarters
OS WER OS WER OS WER
/£ DIRECTIVE DIRECTIVE
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CORRECTIVE ACTION. DOC: 9502.01(84)
Key Words: ' Refinery Wastes
Regulations: HSWA §206, 40 CFR 261.21-24
Subject: Permitting of Refinery Oily Wastewater Treatment Ponds
Addressee: Robert L. Duprey, Director, Air and Waste Management Division,
Region VIII
Originator: John H. Skinner, Director, Office of Solid Waste x
x.
Source Doc: #9502.01(84)
Date: - 12-07-84
Summary:
Downstream unit sludges from unlined wastewater ponds that treat or store
oily wastewaters are similar to those found in the API separator but are not a
sufficient basis for defining the material in the downstream units as API
Separator Sludge. The Agency is planning to regulate oil/water/solids separation
sludges generated in the wastewater treatment system prior to biological treatment
There are three ways to regulate these pond sludges:
1) According to HSWA §206, if a refinery pond is releasing hazardous
constituents and the refinery seeks a RCRA permit for any unit at that
facility, the refinery must undertake corrective action for the releases
from the pond. (This could be done through the permit, or pursuant to
an interim status compliance order.)
2) The wastes could be regulated as hazardous if they exhibit one or more
of the characteristics of hazardous waste (40 CFR 261.21-24).
3) Apply the mixture rule in cases where previously deposited sludge from
., ._ _ a separator is scoured,- resuspended and t-hen carried out of the unit- -
with the wastewater. The wastewater becomes a hazardous waste until
delisted or discharged to a stream subject to regulation under the
Clean Water Act. The mixture rule cannot apply, however, where the
API Separator is inefficient and allows sludge to be carried through
to a.pond, or where downstream oxidation ponds receive flow that
bypassed the API Separator.
EPA bears the burden of proof on the demonstration of>the application
of the scouring argument. This technically complex argument can be
based on established scouring hydrodynamic principles. HQ developed
guidance to facilitate the application of the scouring argument. A
list of factors was developed to evaluate whether scouring from a given
separation occurred. The factors include:
o Sludge Accumulation Practices o Separator Effluent
o Flow Variability Characteristics
o Poor Separator Design or Operations o Sludge Characteristics
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MEMORANDUM
*
SOBJECT- Region vin poll-
" '' Oily Wastewater T
.«.««" ' *.
FROMs John H. Skinner. Dt
: Office of Solid Waste (WH-562)
»«-...
TO; Robert L. Duprfey, Director
Region 8 - - -
Air and Wast2 Management Division (8AW-WM)
- i -. ' - - .
We have reviewed the proposed Region VIII position
discussed in your memo* dated May 1 and October 12. 1934 that
;deflne permitting coverage of refinery wastevater traatjnent
ponds. As your staff »ay have informed you, there have been
several meetings between ay staff and yours to discuss this
problem. We have also net with Chevron. Phillips. Tosco and
API anrt, separately, with Rag ion IX to discuss the issue. We
share your concern about the throat posed to ground and surface
waters by aooe of the unlined wastewater ponds that treat or
store oily wastevatera. However, wo believe that the similarity
of downstream unit sludges (in terms of lead and chromium levels)
to those found in the API Separator are not a sufficient basis
for defining the material in the downstream units as API
Separator Sludge. In fact, the similarity of these sludges was
a significant factor In our decision to nove forward on an .
expanded listing to regulate these pond sludges.
Specifically, we are planning in a forthcoming listing to
e1 oi1/vater/solids separation sludgos generated in the
treatment system prior to biological treatment. This
listing was originally proposed in Nov»»mb«»r of I9fl0. We expect
to issue a notice Identifying all of the available data in support
of the listing and to provide sone clarifications in response to
previous comments. Current plans are to proaulgata that listing
by lato summer.
While the listing revision should cov«?r nost sludges generated
in these ponds, we realize that does not address your short term
problem. He do have some suggestions in this regard. Section
206 of the Hazardous .and Solid Waste Amendments of 1984 provides
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that persona obtaining RCRA permits must undertake corrective
action for all releases of hazardous constituents from any
solid waste management unit as a condition of obtaining the
RCRA pnrait. Thus, if a refinery pond Is releasing hazardous
constituents and the refinery seeks a RCRA permit for any
unit at that facility, the refinery would have to undertake
corrective action for the releases froa the pond. (This could
be done either through the permit, or pursuant to an Interia
status compliance order.) This principle applies even 1£ the
pond is not considered to hold a hazardous waste, since Section
206 Applies to releases of hazardous constituents from solid
waste management units. ..«..,
«-<**« A second option for addressing these pond sludges Is to
regulate the wastes as hazardous based on their exhibiting one
or more of the characteristics of hazardous waste (see 40 CrR
f261.21 -24). You mentioned this option In your recent letter
with respect to 8P Toxieity. However, your staff seems to have
overlooked corroslvity (high pfl has been found in some COO ponds)
and reactivity ($261.23(a)(5)). It Is likely that some refinery
pond sludges will contain excessive levels of reactive sulfldes.
\ The final option that could be used to deal with downstream
'- Impoundments and basins is applicability of the mixture rule. It
is imperative, however, that your staff understand the proper
framework for the application of the mixture rule. To maintain
that a pond is regulated because an API Separator is an inherently
inefficient unit and allows sludge to bo carried through to a
pond, is Inaccurate. Likewise, downstream oxidation ponds are
not regulated simply because they aoaetimes receive flow that
has bypassed the API Separator. In both cases, the listed API
Separator Sludge has not yet been generated. Rather, API
Separator Sludge la generated when it is deposited in the bottom
of an API Separator. The mixture rule is relevant only in those
casos where previously deposited sludge is scoured, reausponded,
and then carried out of the unit with the wastawater. If the
Region can make a case for scouring from a separator, the mixture
rule ia applicable and the wastowater becones a hazardous'wasta
until delisted or discharged to a stream subject to regulation
under the Clean Water Act.
The burden of proof in th« demonstration of scouring ia
upon the Agency. Such an argument, although technically complex,
can be made based on well established hydrodynamic principles.
Realizing that there are limited resources and capability Cor
developing such an arqument by the Regions, we have (at the
request of your staff) taken an active role in the development of
guidance for the application of this argument. Attached to this
mereo is a proliminary list of factors that nay be required to
establish the occurrence of scouring frora a given separator.
These points are being provided at thla time to facilitate the
initiation of information gathering in the more serious cases.
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We hav«> also requested that th« Office of Waato Programs
Enforcement (OWP8) develop nor* thorough guidance. That effort
is being conducted by their contractor (Metcalf 6 Eddy). We
anticipate that your staff will be contacted by then in the near
future Ttie> contractor should be able to provide so*e direct
assistance to your staff in soara specific cases, thereby serving
the dual purpose of training and resolution of specific factors
of concern. Nike Barclay (PTS: 475-9727) of OWPE is the Read-
quarters lead on that project and should be contacted for any
further information. Ben Smith of my staff (PTSi 475-9531) is
our technical expert in this natter and the lead on our study
of petroleum refineries and their wastes. Do not hesitate to
contact hits if additional questions arise pertaining to thla or
Bother natters.
cc RA'a Region I-X
Hike Barclay (OWPE)
Stevo Slvernan (OGC)
Susan Hanganello (ORC, Region.VIII)
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Factors To Be Evaluated In Do terra in ing The potential for
% *
. j
Separator Sludge Scouring
Sludge Accumulation Practices - Continuous sludge removal"*
from tho separator rules out the occurrence of scouring.
At the other end of the spectrum are facilities that allow
_ sludge to accumulate to considerable depth. Accumulation
-".. to a depth greater than 5O% of the flow depth makes scouring
' probable, intermediate ranges of accumulation will prob- ...»..,
-*, ably depend more heavily on other factors* -" '-- - - '
Variablity - Unless overloaded, units with maximum-
to-minimum, flow ratios at tho separator effluent of less
than 2 and Inlet flow ratios of less than 4 are probably
^/- not experiencing 'much rosuspension of sludge. . .
?>".. . '-'-.' -.- ' -". ""
'* Poor Separator Design or Operation - Factors contributing
;.' to scour conditions include t excessive, inlet or outlet.
/.zone turbulence; nominal horizontal velocities greater
rr-"than 30 feet per minute; nominal overflow rates (flow/
7 -surface area) greater. than 10,000 gallons per day/square
v foot of basin; basins less than 30 feet in length; opera-
&'- t ion 'under pressure (e.g., with a backwater at the' inlet
^ of a separator with a -frozen surface), settling zone
~ turbulence (sometimes seen as bubbling with solids
_.'- entrainment) . " '" " '" ' ' \-
',* Separator effluent Characteristics - Excessive weir loadings
(e.g., operation with a suppressed weir, flow depth greater
than a foot) facilitate carryover of resuspended particles.
Visible, large (diameter greater than 1/4 Inch) sludge .'.
particles in the separator effluent are strong evidence
of scouring associated with microbial degradation of ^
deposited sludge."
Sludge Characteristics - Particle size distribution as "/..*
measured toy wot sieve and hydrometer analyses is necessary
information to define scour conditions. -The presence of -..
coke fines in the wastewater influent is also important
because that size of particle «.lmm) is non-cohesive
and highly susceptible to rosuspension.
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