United States
Environmental Protection
Agency
Industrial Environmental
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-84-115 Aug. 1984
Project Summary
Logan Wash Field Treatability
Studies of Wastewaters from Oil
Shale Retorting Processes
B.O. Desai, D.R. Day. and I.E. Ctvrtnicek
Treatability studies were conducted
on retort water and gas condensate
wastewater from modified in-situ oil
shale retorts to evaluate the effective-
ness of selected treatment technologies
for removing organic and inorganic
contaminants. At retorts operated by
Occidental Oil Shale, Inc., at Logan
Wash, Colorado, treatability studies
were conducted on retort water using
filter coalescing, steam stripping, acti-
vated sludge treatment (both with and
without powdered activated carbon
addition), sand filtration, and granular
activated carbon adsorption. Retort
water had high concentrations of
ammonia-nitrogen, total Kjeldahl nitro-
gen, alkalinity, dissolved organics,
phenols, sulfide, total dissolved solids,
boron, potassium and sodium. Steam
stripping removed ammonia-nitrogen,
alkalinity, and sulfide from retort water
and organics removal was low. Gas
condensate wastewater had high con-
centrations of ammonia-nitrogen, total
Kjeldahl nitrogen, dissolved organics,
alkalinity, phenols, sulfide, and pyridine
compounds. The overall scheme for the
gas condensate treatment removed
ammonia-nitrogen, total Kjeldahl nitro-
gen, alkalinity, sulfide, biochemical
oxygen demand, dissolved organic
carbon, chemical oxygen demand, and
phenols.
This Project Summary was developed
by EPA 's Industrial Environmental
Research Laboratory. Cincinnati, OH,
to announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
To assess the characteristics and
treatability of wastewaters generated
from the processing of oil shale, the U.S.
Environmental Protection Agency (EPA)
contracted with Monsanto Research
Corporation (MRC) in 1979 to conduct a
five-phase program entitled "Assessment
of Oil Shale Retort Wastewater Treatment
and Control Technology." The program
had the following objectives (phases):
I Summarize available information
concerning oil shale retort waste-
water sources and characteristics;
II Identify control technologies that
are potentially applicable for treat-
ment of the identified wastewater
streams;
III Design pilot-scale units capable of
evaluating the applicable technol-
ogies at oil shale processing sites;
IV Construct the pilot-scale units;
and
V Operate the units and evaluate
treatment technology perform-
ance.
Based on the results of Phases I and II, it
became apparent that not much informa-
tion existed on which to evaluate and
select potentially applicable technologies
for testing and that laboratory bench-
scale testing and wastewater characteri-
zation were warranted. Wastewater cha-
racterization and bench-scale treatability
studies were conducted using samples of
oil shale wastewaters available at the
time. Steam stripping, hyperfiltration,
carbon adsorption (batch isotherm and
column), and activated sludge treatment
tests were conducted on a bench-scale
level. The results of these studies and the
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information previously collected during
Phases I and II were used to select the
treatment schemes and units for con-
struction and field testing under the
follow-up Phases III through V. The
schemes and units approved by EPA with
some modifications were field tested at
the modified in situ retorts operated by
Occidental Oil Shale, Inc., in Logan
Wash, Colorado.
Oil shale retorts generate gases and an
oil/water mixture from shale pyrolysis,
combustion of carbonaceous residues, and
decomposition of inorganic carbonates.
As shown in Figure 1, off-gases generated
from an in-situ retort exit the retort
bottom and are brought to the surface for
treatment. The retort oil/water mixture
accumulates in the product collection
sump at the retort bottom and is subse-
quently pumped out and treated to
recover the bulk of the shale oil. The
separated gas condensate and retort
waters are the wastewaters which were
studied at the Logan Wash field site.
At Logan Wash, treatability studies
were conducted for three weeks on retort
water using filter coalescing, floccula-
tion/clarification, and steam stripping
technologies (Figure 2). Also, studies were
conducted for 14 weeks on gas conden-
sate wastewater using filter coalescing,
steam stripping, conventional and pow-
dered activated carbon (PAC) activated
sludge treatments, sand filtration, and
granular activated carbon adsorption
technologies (Figure 3).
The test equipment and supporting
field laboratory for conducting the
treatability studies were either provided
by EPA or procured by MRC. Equipment
layout at the trial location is shown in
Figure 4. Analytical methods utilized
adhered to Standard Methods when
applicable.
Test Results
Retort Water - Overall
Treatment
Retort water was treated primarily to
remove oil and grease, suspended solids,
ammonia, and alkalinity. The filter
coalescer, flocculator/clarifier, and
steam stripper in series were used to
remove these pollutants. The overall
treatment scheme was very effective for
ammonia and alkalinity removal (Figure 5).
Relatively high sulfide, TKN, and phenols
removals were also achieved. Due to low
levels of oil and grease, and suspended
solids, the scheme was not effective in
removing these pollutants.
Product Oil
^ Off-Gas
\~~ (Noncondensible)
•
Gas Condensate ^ „ , 1
Water "*" Conderuen |
Air/Steam—^ m
-»•
Oil /Water
Separation
\
Retort Water
Rubblized
Shale
\OH/Water
Product
Collection Sump
Figure 1. Production of gas condensate and retort waters by modified in-situ (MIS) retorting.
Raw Retort
Water
Flocculator
Clarifier
I
Steam
Stripper
Figure 2. Retort water treatment scheme.
Gas Condensate - Overall
Treatment
Filter coalescing, steam stripping,
conventional activated sludge treatment,
sand filtration, and GAC adsorption
comprised the overall treatment scheme
for the gas condensate. The scheme was
very effective in removing ammonia,
organics, sulfide, alkalinity, and solids
from the gas condensate. Assuming
conditions listed below, the scheme
would produce a final effluent with the
expected composition presented in Table
1.
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Activated Sludge
Waste
Sludge
Overhead
Vapor
_ Raw Gas
' Condensate
Filter
Coalescer
Light ±
Oils "
Steam,
Steam
Stripper
Gravity
Separator
Aeration Basin
(With/Without
Powdered
Activated Carbon)
Return Sludge
Granulated.
Activated
Carbon
Columns
Discharge
Light
Oils
Figure 3. Gas condensate wastewater treatment schemes.
Steam stripper:
GL/ratio =0.15 kg/liter
(1.2lb/gal)
Activated sludge system:
Hydraulic retention time = 16 hours
Sludge age = 32 days
GAC column:
Contact time = 19 minutes
The other treatment scheme comprised
filter coalescing, steam stripping, and
GAC adsorption. The scheme was effec-
tive in removing ammonia, organics,
sulfide, alkalinity, and solids from the gas
condensate. But, the performance of
granular activated carbon adsorption was
relatively poor and this scheme was less
effective in removing pollutants than the
one with an activated sludge system
included.
Conclusions
Pilot-scale field treatability studies on
real-time oil shale wastewaters from
Occidental in-situ MIS retorts demon-
strated that retort water had high concen-
trations of ammonia, TKN, alkalinity,
dissolved organics, phenols, sulfide, and
TDS; and gas condensate had high
concentrations of ammonia, TKN, dis-
solved organics, alkalinity, phenols, and
sulfide. Steam stripping was effective in
removing ammonia and alkalinity from
the retort water. Steam stripping, acti-
vated sludge treatment - both conven-
tional and PAC, sand filtration, and GAC
adsorption were effective in removing
ammonia, alkalinity, TKN, nitrate, soluble
COD, soluble BODs. DOC, phenols,
sulfide, and TSS from the gas condensate.
Pollutant removal efficiencies across
individual treatment units for retort water
and gas condensate treatment schemes
are presented in Tables 2 and 3, respec-
tively.
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Wastewater
Supply Tank
28 kiloliters
(6.000 gallons)
Elevation: 18 meters (60 ft)
Above Product Level
Retort
Water
Trailer
2.4 m,x'13.7 m
<8'x45')
Trickling
Filters
(Not Used)
•5
1
Filter
Coalescer
Gas
Condensate
Trailer
2.4mxil3.7m
<8'x45l)
O O
EZU
Laboratory
Waste Storage
2 kiloliters
(500 gal.)
Laboratory Trailer
2.4 mx 7.6 m
(8'x25')
Carbon
Adsorbers
i
Media
Filters
Stripper Skid
2.4 m x 6.1 m
(8'x20')
fSteam
\Stripper
Q
Boiler Skid,
2.4 x 4.6 m
(8' x 15')
Boiler Feed
rij- Water Tank
130 liters
LJ (35 gal.)
Water
Softener
Fresh
Water
Storage
15 kiloliters
Stripper Overhead _-
Storage 870 liters (230 gal.}
Air
Compressor
Trial Location Area
__, 18.3 m x 24.4 m (60' x 80')
on Product Level
Elevation: 2,300 meters
(7.700ft)
Effluent
Sump
Tank
1.100 liters
(300 gal.)
Fresh Water
Supply and
Distribution System
Elevation: Below Product Level
Fuel Oil Storage
15 kiloliters
(4,000 gal.)
Figure 4. Equipment general layout at the trial location.
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700
901
70
60
5 50
o
i
40
30
20
10
Ammonia
,0
Alkalinity
I
0.06
(0.5)
0.12
(1.0)
0.18
(1.5)
0.24
(2.0)
0.30
(2.5)
G/L Ratio, kg/steam/liter feed water (Ib steam/gallon feed water)
Figure S. Percent ammonia and alkalinity removal from retort water as a function of G/L ratio
in the steam stripper.
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Table 1. Overall Gas Condensate
Parameter
NH3-N
TKN
NO3-N
Soluble COD
Soluble BODs
DOC
Phenols
Sulfide
TSS
VSS
Alkalinity as CaCO3
to pH 4.5
pH*
Oil and greasec
Treatment Scheme Performance Summary
Concentration,
Raw
wastewater
9.000
6,800
1.1
2.700
8OO
890
120
72
7
5
31.000
8.5
mg/L
Final
effluent
90
180
0.4
50
20
25
0.02
2
5
5
350
7.5
Percent
removal
99
97
64
98
98
97
100
97
29
0
99
NA*
'Standard pH units.
"NA - not applicable.
"Oil and grease were at low levels (average 18.6 mg/L) in the gas condensate received for testing;
however, an oil and grease removal treatment step may be necessary if the raw gas condensate has
a relatively high oil and grease level.
Table 2.
Pollutant Removal Efficiencies Across Individual Units for Retort Water Treatment
Scheme*"
Parameter
Oil and grease
Ammonia
TKN
Soluble BODS
DOC
Phenols
TSS
VSS
Alkalinity as CaC03
to pH 4.5
Fluorides
Chlorides
Filter
coalescer
6
21
20
Flocculation
clarification0
0
7
11
Steam
stripper6
97
88
5
4
32
47
"Average removal efficiencies are reported.
''Blanks indicate data not collected.
°Lime dosage at 9O mg/L.
"G/L = 0.18 kg/L (1.5 Ib/gal).
Table 3. Pollutant Removal Efficiencies A cross Individual Units for Gas Condensate Treatment
Scheme"'"
Treatment unit
Filter
Parameter coalescer
Oil and grease 28
Ammonia
TKN
Soluble COD
Soluble BODs,
DOC
Phenols
Sulfide
TSS
Alkalinity as CaCO3 to
pH4.5
Steam
stripped
99
96
56
60
29
97
99
Activated
sludge
treatment11
6
59
91
52
93
GAC
Sand adsorption
filter column*
95
70
89
99.5
70
"Average removal efficiencies are reported.
^Blanks indicate data not collected.
CG/L = 0.19 kg/L (1.6 Ib/gal) average.
"Hydraulic retention time =16 hours, sludge age - 32 days.
"Contact time =19 minutes.
*USGPO: 1984-759-102-10653
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B. O. Desai. D. R. Day, and T. E. Ctvrtnicek are with Monsanto Research
Corporation, Dayton, OH 45418.
W. W. Liberick. Jr. is the EPA Project Officer (see below).
The complete report, entitled "Logan Wash Field Treatability Studies of
Waste waters from Oil Shale Retorting Processes," (Order No. PB 84-211 143;
Cost: $17.50, 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
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
It-
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