v-xEPA
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S7-81-081 May 1981
Project Summary
Assessment of Oil Shale
Retort Wastewater
Treatment and Control
TechnologyPhases I and II
J. R. Klieve, G. D. Rawlings, and J. R. Hoeflein
Oil shale retorting is a synthetic fuel
production technology on the verge of
commercialization in the United
States. In order to ensure that the
emerging oil shale industry will have
minimal adverse effects upon surface
and/or groundwater where recover-
able reserves of oil shale are found,
demonstrated technologies to
upgrade oil shale wastewaters must
be available to developers. To this end,
the U.S. Environmental Protection
Agency has contracted with Monsanto
Research Corporation (MRC) to
conduct a three-year, five-phased
study to: (1) summarize known
information concerning oil shale retort
wastewater sources and characteris-
tics; (2) identify potentially applicable
control technologies capable of treat-
ing the identified wastewater streams;
and (3) design, construct, and operate
pilot-plant facilities to evaluate the
selected technologies. This report
presents results Of Phases I and (I, in
which literature and other information
sources were surveyed to obtain rele-
vant data about oil shale retorting
technologies, wastewater sources
and characteristics, potential waste-
water uses, and potentially applicable
treatment technologies. As a result of
the study, data gaps were identified,
and recommendations for bench-
scale treatability studies were made.
This Project Summary was develop-
ed by EPA's Industrial Environmental
Research Laboratory, Cincinnati. OH,
to announce key findings of the
research project that is fully docu-
mented in a separate report of the
same title (see Project Report ordering
information at back).
Technical Discussion
In-situ retorting, which consists of
heating shale underground after
modification of the permeability of the
rock formation, is being investigated by
Dow Chemical Co., Equity Oil Co., Geo-
kinetics, Irfc., Occidental Oil Shale, Inc.,
and Rio Blanco Oil Shale Co., all of
which are now conducting process
development efforts. Processes being
developed by Paraho Development
Corp., Superior Oil Co., TOSCO Corp.,
and Union Oil Co., are classified as
surface retorting, in which mined,
crushed shale is heated in above-
ground metal vessels to produce crude
oil. Although many process variations
exist within the two major retorting
process categories, in-situ and surface,
distinct wastewater streams are
common to most processes within each
category. From in-situ retorting, three
major streams emanate: mine water,
retort water, and gas condensate. Mine
water is thatwater pumped from a shale
formation prior to ignition. Retort water
is formed when water vapor condenses
in cool, rubblized shale ahead of the
flame front during retorting. Gas con-
densate is that water which leaves the
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retort as a gas and is recovered when
gas from the in-situ retort is cooled.
From surface retorting, three major
streams are envisioned: gas conden-
sate, product water, and spent shale pile
leachate. Water normally leaves the
surface retort in the vapor phase and is
recovered as gas condensate when the
retort gas is cooled prior to purification.
In addition, water separates from the
product oil following oil/gas separation
and is termed product water.
Since spent shale from surface retort-
ing is to be disposed of above ground,
leachate through the shale pile is
another potential wastewater stream.
Mine water has been found to exhibit
high levels of alkalinity, chemical
oxygen demand (COD), chloride, fluo-
ride, sulfate, boron and sodium. Exis-
tence of trace metals are of particular
concern, since some mi'ne water will be
discharged to the environment.
Retort wastewater and product
wastewater contain high levels of most
pollutants identified. Gas condensate
wastewaters exhibit high levels of
ammonia, alkalinity, and organics;
however, concentrations of trace
metals are significantly lower in gas
condensate than in retort wastewater.
Limited data are available to character-
ize leachate; however, high levels of
organics, total dissolved solids (IDS),
sulfate, and sodium have been
exhibited.
Water-use schemes developed by
industry and government contractors
have been reviewed. Most water-use
schemes suggest use of wastewater
within the retorting facility; however,
there appears to be little technical
information to support this approach.
Available information relating to the
treatability of individual retort streams
was summarized and significant data
were obtained only for the treatability of
mine water and combined retort/prod-
uct water.
In the case of mine water, activated
alumina absorption, precipitation with
phosphoric acid and lime, and ion
exchange have been demonstrated in
bench-scale screening tests to remove
fluoride and/or boron. Additional tech-
nologies should be used for dissolved
gas removal, suspended solids removal,
IDS removal, and disinfection, particu-
larly if the water is discharged or used
for. potable needs.
Many research studies have focused
on the treatment of retort/product
water. There remain, however, key
technical questions in the area of emul-
sified oil separation and organics
removal. Steam stripping has been
identified as a promising technology for
dissolved gases removal. Granular acti-
vated carbon and polymeric resins have
been demonstrated for gross organics
removal; however, for cost considera-
tions, aerobic biological treatment
should be the focus for gross organics
removal, with carbon and polymeric
resins used to remove refractory
organics.
No research activity in the area of gas
condensate treatment was identified;
however, steam stripping should ade-
quately treat gas condensate for in-
plant use.
In the case of leachate, it is recom-
mended that funds be used to identify
leachate as a major wastewater stream
and characterize it, rather than investi-
gate treatment alternatives. If leachate
is found to be a significant wastewater
stream, serious questions regarding
leachate collection arise.
Several treatability screening studies
have been conducted to fill many treat-
ment step needs identified in Figures 1
and 3, particularly in the case of mine
water and retort water treatment. Be-
cause of their design and intent, these
studies have generally been useful to
screen some potential technologies and
eliminate others. Many key technical
questions still remain unanswered such
as:
How should emulsified oil be
separated in retort and product
water?
What is the best system for re-
moval of organics from retort and
product water?
Will state-of-the-art technologies
treat gas condensate and
leachate?
To answer these questions, and to size
pilot-plant equipment, MRC recom-
mends conducting additional bench-
scale treatability studies. Presently,
there are several opportunities for MRC
to obtain relevant samples of retort
wastewaters with which to conduct
these studies, namely:
Rio Blanco mine water and
retort water
Tosco gas condensate
Geokinetics retort water
Occidental retort water and gas
condensate
In the case of mine water treatment,
only Battelle N.W. has conducted
bench-scale treatability studies for the
removal of fluoride and boron which are
of primary concern if the excess mine
water is to be discharged or used for
potable purposes. Activated alumina
absorption and precipitation with phos-
phoric acid and lime were identified as
promising technologies for the removal
of boron. The literature reported that
electrodialysis and reverse osmosis
could produce a more than adequate
effluent; however, reverse osmosis
appears to be more cost-effective at the
high TDS levels expected and has other
technical advantages as well.
Thus, additional research is needed to
demonstrate the feasibility of reverse
osmosis treatment of mine water and to
size pilot-plant equipment in the case of
other treatment steps.
Suggested technology options to be
investigated in these studies are listed
in Figure 1.
Many more studies have been con-
ducted with retort water; however, key
technical questions remain; e.g., no
studies have been conducted to investi-
gate emulsified oil separating from
retort and product water. Steam strip-
ping has been identified by several
investigators as the best technology for
dissolved gases removal, though fouling
of column packings has been experi-
enced. Emulsified oil separation may
alleviate the problem. Although many
studies have been conducted to assess
technologies for organics removal,
many questions remain. Aerobic bio-
logical treatment has classically been
the most cost-effective method of
organics removal from municipal
wastes, but various pretreatments are
required for these systems to operate
with retort water; also, a large portion of
the organics (50%) appear to be refrac-
tory. Therefore, additional studies are
needed to identify methods which
would enhance -the ability of aerobic
biological treatment to remove organic
compounds. The sensitivity of biological
systems to variations in retort water
composition has serious implications
for commercial operations. If it is found
that wastewater cannot be treated bio-
logically, it may become necessary to
test physical/chemical methods such .
as wet air oxidation and granular'
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Potential End Use
Reinfection
Treatment Steps
Mine Water
Treatment Options
Dissolved Gases
Removal
Clarification
Fine S.S.
Removal
Cooling Tower
Makeup
Discharge
TDS/Trace Metals
Removal
Residual
Inorganics
Removal
Boiler Feed
Potable Use
Aeration
Chemical Addition/
Flocculation/
Sedimentation
Multimedia
Filtration
Reverse Osmosis
Ion Exchange
Ion Exchange
Cl2
retort water are envisioned. Bench-
scale studies conducted at this time are
still recommended to complete a retort
treatability data base which would be
used by industry and government in
making water-use decisions.
Although no known studies exist for
the treatment of gas condensate, this
stream should not be difficult to treat,
compared to retort water. At this time,
the extent to which emulsions are
present in gas condensate is not known.
If present, they will have to be removed
prior to subsequent treatment steps.
Steam stripping studies are necessary
to assess organics removal as well as
inorganic dissolved gases removal. If
organics remain following steam strip-
ping, studies for their removal will have
to be initiated.
Suggested technology options for gas
condensate treatment are listed in
Figure 3.
Since it is not known whether
leachate from spent-shale piles will be
present in significant quantities, and
leachate quality is still not fully
understood, research funds should be
directed to address these issues rather
than investigating treatment alterna-
tives. If spent-shale piles are found to be
porous, and the leachate from
percolation through the piles is toxic or
unacceptable for groundwater
discharge, serious questions about
leachate collection in full-scale systems
exist.
This report was submitted in partial
fulfillment of Contract No. 68-03-2801
by Monsanto Research Corporation
under the sponsorship of the U.S.
Environmental Protection Agency. This
report covers the period May 1979 to
March 1980; work was completed as of
February 1980.
Figure 1. Mine water treatability options.
activated carbon adsorption. It is unlike-
ly that retort water would be discharged
from a full-scale retorting facility; how-
ever, if discharge is necessary,
treatment for trace organics, trace
metals, and TDS will become necessary.
Several investigators have used
granular activated carbon and
polymeric resins for gross organics
removal; however, studies are needed
to assess these technologies for their
, ability to remove refractory organics
present in the effluent from the gross
organics removal treatment step.
Studies of TDS and trace metals
removal by reverse osmosis and ion
exchange would also become neces-
sary.
Suggested treatment options to treat
retort water to discharge quality are
shown in Figure 2.
Treatment to discharge quality will
probably not be necessary in full-scale
systems since many in-plant uses for
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Potential End Use Treatment Steps
Retort Water, Product Water
Steam
Generation
Via Thermal
Sludge Oxidizer
Emulsified (?) Oil
Separation
Dissolved Gases
Removal
Organics
Removal
Fine S.S.
Removal
Dust Control
Shale
Moistening
Scale Control
Cooling Tower
Makeup
Discharge
Gravity Separation
Chemical Addition/DAF
Chemical Emulsion
Breaking/Separation
Ultrafiltration
Steam Stripping
Aerobic Biological
Treatment With One or
More Pretreatments:
-pH Adjustment
-Chemical Coagulation
-Wet Air Oxidation
-Ozonation
-PAC Addition
Wet Air Oxidation
Granular Activated Carbon
Multimedia Filtration
Chemical Addition
Trace Organics
Removal
TDS/Trace Metals
Removal
Granular Activated Carbon
Polymeric Resins
Reverse Osmosis
Ion Exchange
Figure 2. Retort wastewater treatability options.
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Potential End Use"1
Treatment Steps Technology Options
Gas Condensates
Cooling Tower '
Makeup
Dust Control
Shale Moistening
Discharge
Emulsified (?) Oil
Separation
Dissolved Gases
Removal
Organics
Removal
Fine S.S.
Removal
Trace Organics
Organics
Gravity Separation
Chemical AdditionYDAF
Chemical Emulsion
Breaking/Separation
Ultrafiltration
Steam Stripping
Aerobic Biological
Treatment
(See Figure 2)
Multimedia Filtration
Granular Activated Carbon
Polymeric Resins
Figure 3. Gas condensate wastewater treatability options.
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J. R. Klieve. G. D. Rawlings, and J. R. Hoeflein are with Monsanto Research
Corporation, Dayton, OH 45407.
W. W. Liberick. Jr.. is the EPA Project Officer (see below).
The complete report, entitled "Assessment of Oil Shale Retort Wastewater
Treatment and Control TechnologyPhases I andII, "(Order No. PB 81-187 288;
Cost: $9.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
» US GOVERNMENT PRINTING OFFICE. 1981 -757-01Z/7H7
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Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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