United States
Environmental Protection
Agency
Robert S Ker- f
Laboratory
Ada CX 74620
Resaarcti and Development
Total Recycle
Systems for
Petrochemical
Waste Brines
Containing
Refractory
Contaminants
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution-sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161
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EPA-600/2-79-021
January 1979
TOTAL RECYCLE SYSTEMS FOR PETROCHEMICAL WASTE BRINES
CONTAINING REFRACTORY CONTAMINANTS
by
M. A. Zeitoun
C. A. Roorda
G. R. Powers
Dow Chemical Company
Freeport, Texas 77541
Grant No. S803085-01-0
Project Officer
Thomas E. Short, Jr.
Source Management Branch
Robert S. Kerr Environmental Research Laboratory
Ada, Oklahoma 74820
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ADA, OKLAHOMA 74820
-------
DISCLAIMER
This report has been reviewed by the Robert S. Kerr Environmental
Research Laboratory, U.S. Environmental Protection Agency, and approved
for publication. Approval does not signify that the contents necessarily
reflect the views and policies of the U.S. Environmental Protection
Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
ii
-------
FOREWORD
The Environmental Protection Agency was established to coordinate admin-
istration of the major Federal programs designed to protect the quality of our
environment.
An important part of the Agency's effort involves the search for informa-
tion about environmental problems, management techniques, and new technologies
through which optimum use of the Nation's land and water resources can be
assured and the threat pollution poses to the welfare of the American people
can be minimized.
EPA's Office of Research and Development conducts this research through a
nationwide network of research facilities.
As one of these facilities, the Robert S. Kerr Environmental Research
Laboratory is responsible for the management of programs to: (a) investigate
the nature, transport, fate and management of pollutants in ground water;
(b) develop and demonstrate methods for treating wastewaters with soil and
other natural systems; (c) develop and demonstrate pollution control technol-
ogies for animal production wastes; (e) develop and demonstrate technologies
to prevent, control, or abate pollution from the petroleum refining and petro-
chemical industries, and (f) develop and demonstrate technologies to manage
pollution resulting from combinations of industrial wastewaters or industrial/
municipal wastewaters.
This report contributes to the knowledge essential if the EPA is to meet
the requirements of environmental laws that it establish and enforce pollution
control standards which are reasonable, cost effective, and provide adequate
protection for the American public.
CJ C. Ji
W. C. Galegar
Director
Robert S. Kerr Environmental Research Laboratory
iii
-------
ABSTRACT
Petrochemical wastewaters containing relatively high concentra-
tions of salt and refractory organics were selected to study
their feasibility for total recycle. A combination of reverse
osmosis and electrodialysis was operated as a hybrid system
using the pretreated wastes, to produce reusable water and a
concentrated brine.
Stream 1, characterized by a salinity of 1.4 percent NaCl when
neutralized, contained an average of 0.5 percent organic amines
and ammonia. It was found to contain enough silica to foul the
membranes. Stream 2, contained 4.5 percent dissolved solids and
precipitated aluminum salts when neutralized with acid. Its
organic content of aromatics averages 90 mg/1 of TOC.
A total recycle system for Stream 1 is composed of ammonia
stripping, carbon adsorption and recovery of the organic amines,
neutralization and silica removal before the ED-RO hybrid. For
a 1 MGD Stream 1 waste treatment facility the estimated capital
cost is $6,949,550 (1975 dollars) and the estimated operating
cost is $5,291,700 per year. The carbon adsorption step has an
estimated operating cost of $2,358,000 recovering organics suit-
able for recycle at an estimated value of $3,000,000 per year.
A total recycle system for Stream 2 is composed of neutralization,
settling and centrifugation to recover Al(OH)3, and carbon adsorp-
tion with thermal regeneration before the ED-RO hybrid. For a 1
MGD Stream 2 treatment facility, the estimated capital cost is
$9,170,000 and an operating cost is $2,293,700 per year. No
valuable organics are recovered from this stream.
The combined electrodialysis-reverse osmosis system is not con-
sidered economically feasible when applied to industrial waste-
waters containing relatively high concentrations of salt.
IV
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CONTENTS
Foreword iii
Abstract **.... iv
Figures vi
Tables viii
1. Introduction 1
2. Conclusions 4
3. Recommendations 5
4. Waste Waters Selection and Characterization 6
5. Stream 1. Total Recycle System 10
Pretreatment Studies 10
Reverse Osmosis and Electrodialysis -
Stream 1 18
Total Recycle System Design and Cost
Estimate 37
6 . Stream 2. Total Recycle System 41
Pretreatment Studies 41
Electrodialysis-Reverse Osmosis
Studies - Stream 2 . 49
Total Recycle System Design and
Cost Estimate 49
7. Economic Evaluation - Brine and Potable
Water Reuse 56
Bibliography 61
Appendices
A. Metric Conversions 63
B. Analytical Methods 64
C. Ammonia Removal Tests 67
D. Total Recycle System Design and
Cost Estimates - Stream 1 75
E. Total Recycle System Design and
Cost Estimates - Stream 2 89
v
-------
FIGURES
Figure Page
1 General Systems Engineering - Total
Recycle System 3
2 Adsorption Isotherms - Stream 1 12
3 Carbon Column Test - Cycle 4 15
4 Regeneration - Activated Carbon - Stream 1 17
5 Silica Adsorption on Activated Alumina 19
6 SV-5 Electrodialysis Unit 20
7 Reverse Osmosis Equipment 22
8 Electrodialysis of Neutralized Untreated
Stream 1 23
9 Electrodialysis of Pretreated Stream 1. 25
10 Electrodialysis of Pretreated Stream 1 -
Limiting Current Density 27
11 Continuous Electrodialysis of Pretreated
Stream 1 Feed 28
12 Continuous Electrodialysis of Pretreated
Stream 1 plus RO Reject Mixture 29
13 Limiting Current Density of Combined
Pretreated Stream 1 and RO Reject Stream 30
14 ED-RO Integrated System Treatment of Stream 1 33
15 ED-RO Combined Operation - Critical Parameters -
Stream 1, without Silica Removal 36
16 ED-RO Combined Operation - Critical Parameters -
Stream 1, with Silica Removal 38
17 Total Recycle System - Stream 1, Flow Diagram
and Material Balance 39
VI
-------
Figures (continued)
Page
18 Gravity Settling - Aluminum Hydroxide Sludge -
Stream 2 43
19 Gravity Settling - Aluminum Solids Flux - Stream 2... 44
20 Carbon Adsorption Isotherm - Stream 2 47
21 Carbon Column Test - Stream 2 48
22 Continuous ED-RO Pretreatment Stream 2 51
23 Total Recycle Stream - Stream 2 53
24 Cost of ED-RO of Brine Solutions - Water Treatment... 57
25 Cost of ED-RO of Brine Solutions - Production
of Process Water 58
26 Cost of ED of Brine Solutions Salt Production 59
27 Cost of ED-RO Treatment of Stream 1 60
C-l Schematic Diagram of Conceptual LMWT Process 69
C-2 Synthetic Stream 1 - Waste Water Liquid
Membrane Treatment 72
C-3 Exchange of NH4+ on Clinoptilolite from
Stream 1 Waste Water. 74
D-l Activated Carbon Treatment of Stream 1 76
D-2 Total Recycle System Stream 1 - Carbon
Treatment Process Design and Material Balance 78
D-3 Total Recycle System Stream 1 - Silica Removal,
Design Basis and Material Balance 84
D-4 Electrodialysis-Reverse Osmosis of Pretreated
Stream 1, Flow Diagram and Material Balance 87
E-l Neutralization and Solids Removal - Stream 2,
Flow Diagram and Material Balance 90
E-2 Flow Diagram and Material Balance for Carbon
Adsorption Treatment - Stream 2 93
E-3 Electrodialysis-Reverse Osmosis Treatment -
Stream 2, Flow Diagram and Material Balance 95
vii
-------
Tables
Table Page
1 Inorganic and Organic Constituents - Stream 1 8
2 Inorganic and Organic Constituents - Stream 2 9
3 Comparison of Commercial Activated Carbons for
Amines Adsorption - Stream 1 13
4 Carbon Bed Test Conditions - Stream 1 14
5 Carbon Bed Test Results - Stream 1 16
6 Pretreated and Neutralized Stream 1 Waste
Water Composition 24
7 Reverse Osmosis Evaluation 32
8 Electrodialysis-Reverse Osmosis Combined Test -
Stream 1 35
9 Cost for Total Recycle System - Stream 1 40
r.
10 Gravity Settling Design Data 45
11 Comparison of Activated Carbons Removal of
Organics for Stream 2 46
12 Continuous Electrodialysis-Reverse Osmosis Run
Pretreated - Stream 2 50
13 Continuous Electrodialysis-Reverse Osmosis Run
with Pretreated Stream 2 52
14 Cost for Total Recycle System - Stream 2 55
B-l Gas Chromatographic Analysis Conditions -
Stream 2 66
C^l Liquid Membrane Treatment of Synthetic Stream 1
Waste Water 71
D-l 1-MGD Stream 1 - Activated Carbon Treatment,
Estimate of Direct Capital Cost 80
viix
-------
Tables (continued)
D-2 1-MGD Stream 1 - Activated Carbon Treatment,
Estimate of Operating Cost 81
D-3 1-MGD Stream 1 - Neutralization, Estimate of
Capital and Operating Costs , 82
D-4 Silica Removal - Stream 1 83
D-5 Activated Alumina Treatment of Stream 1 -
Estimate of Capital and Operating Costs 85
D-6 1-MGD Stream 1 - Electrodialysis-Reverse
Osmosis Design 86
D-7 Cost Estimate Summary - Electrodialysis-
Reverse Osmosis Treatment of Stream 1 88
3.x
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SECTION 1
INTRODUCTION
Petrochemical process waste streams have varied chemical con-
stituents. Some components are easily degradable and are amenable
to biological treatment processes, some are not, while others are
toxic to living matter. Consequently, an optimal balance between
physical, chemical, and biological treatment must be considered
in the development of total recycle and reuse master plan.
Most of the highly contaminated waste streams from petrochemical
plants originate from process areas, including condensed steam
from stripping operations, wash waters from drum cleaning opera-
tions, water formed or eliminated during various reactions and
other similar in-process sources. A variety of contaminants are
found in these waste waters, including unreacted feed stock
chemicals, products, by-products, side-products and spent cata-
lytic materials.
Caustic washes and acidic washes are frequently used to extract
or neutralize acidic and basic components from process streams
resulting in a waste stream containing inorganic salts in addition
to the organic components.
Refractory (non-biodegradable) pollutants are of special interest
because of their possible adverse effects and their persistence
in the environment. The establishment of more stringent effluent
quality standards will necessitate greater utilization of advanced
treatment processes. At the present time, however, application
of advanced treatment methods to petrochemical wastes has been
limited. In addition, there are many unanswered questions regard-
ing the treatment and/or recovery of chemicals resistant to
biodegradation. Although the salvage of unreacted chemicals and
recovery of usable products and by-products from waste waters is
desirable, economic considerations have usually dictated treat-
ment rather than recovery.
The evaluation and development of advanced chemical and physical
treatment methods, and the determination of the proper integra-
tion of selected unit operations to constitute an optimum waste
treatment system is necessary. A system of total recycle involves
both component recovery and water reuse.
-------
The types of physical and chemical treatment processes commonly
investigated for the treatment of petrochemical wastes include
stripping, adsorption, extraction, ion exchange and oxidation.
Because these wastes almost invariably contain dissolved salts,
desalination methods such as reverse osmosis and electrodialysis
are required to concentrate the inorganic components of the waste
streams (total recycle system).
The Dow Chemical Company has investigated electrodialysis as a
process for the concentration of desalination plant brines for
the Office of Saline Water. Under OSW Contract No. 14-30-2676,
Dow designed and built an electrodialysis brine concentrator
which operated at Roswell, New Mexico from February 1971 to
August 1972. The Dow testing concluded under Contract No. 14-30-
3031 with the combined operation of a hybrid reverse osmosis-
electrodialysis pilot plant from August 1972 to May 1973.
Results of the operation of the Roswell facility showed that
reverse osmosis and electrodialysis can be utilized together to
produce desalted water and concentrated brine. For a variety of
feed water salinities, the reverse osmosis-electrodialysis system
can economically achieve a high degree of separation between the
water and the salt.
The capabilities of reverse osmosis and electrodialysis com-
plement each other well. Reverse osmosis produces a low salt
product quite well from brackish water but is a poor brine con-
centrator. Electrodialysis easily produces a ten to fifteen-fold
concentration of salt in a single stage but often requires
several stages operated in series to produce a satisfactory de-
salted water quality. The operation at the Roswell plant de-
monstrated that the combination of electrodialysis and reverse
osmosis can be used to simultaneously concentrate the reject
wastes from the reverse osmosis unit to more than 20 weight
percent sodium chloride and produce reusable product water.
A general schematic of the total recycle system studied is shown
in Figure 1. The main objective of this investigation was to
apply the necessary combination of these unit operations to each
of the simulated wastes so as to approach a total recycle system.
-------
Feed
ontaining
HN3
d
H
ft
ft
-H
H
-P
CO
U)
Feed
Containing
Organic
Contaminants
Regenerant
NH3.to recovery system-
-X-
d
o
o -P
XI ft
t_.t y j
rd o
u w
Feed
Chemical
Oxidation
Regen-
-ป
erant
-------
SECTION 2
.CONCLUSIONS
Petrochemical waste waters containing relatively high concentra-
tions of salt and refractory (non-biodegradable) organic con-
taminants can be treated to remove the organics by such methods
as carbon adsorption. The remaining salt solution can be concen-
trated by an electrodialysis-reverse osmosis desalination process
to produce fresh water and concentrated brine.
For the type of petrochemical waste waters studied, the following
conclusions could be made:
1. The carbon adsorption of relatively high concentrations
of organics from petrochemical waste waters is tech-
nically achievable, but economically feasible only if
the organics can be recovered and recycled to the
production facility.
2. Low concentrations of organics that are highly adsorb-
able on activated carbon cannot be removed from petro-
chemical waste waters, at a reasonable cost, because of
the cost of regenerating the carbon thermally.
3. The combined electrodialysis-reverse osmosis system is
technically a feasible desalination process that pro-
duces both concentrated brine and fresh water.
Pretreatment of the waste water is required to remove
any contaminants that can foul the membranes of the ED
or RO units.
4. For the range of salt concentrations (1.5-4.5 percent
NaCl) studied, the combined electrodialysis-reverse
osmosis system capital and operating costs were found
to be high and the return from the value of the brine
and fresh water produced would not economically justify
the investment in the process equipment.
-------
SECTION 3
RECOMMENDATIONS
It is recommended that:
1. In-place regeneration of activated carbon be investigated
for each particular waste water in order to reduce the cost
of the carbon adsorption treatment.
2. Whenever possible, waste waters containing high salt concen-
trations should be recycled without desalination and/or
concentration.
3. The application of a combined electrodialysis-reverse
osmosis system would be limited to salt concentrations and
situations where it is economically feasible.
-------
SECTION 4
WASTE WATERS SELECTION AND CHARACTERIZATION
Five waste waters were initially considered for the demonstration
of the total recycle concept. All were brines resulting from the
production of petrochemicals and contained various organic con-
taminants known to be refractory to biological oxidation. An in-
depth characterization survey was done on the two waste waters
selected for demonstration. The results of the study of the
first two waste waters and a cost analysis of electrodialysis-
reverse osmosis treatment of these brines led to the decision to
minimize characterization of the last three waste waters because
these contained much higher salt concentrations and were much
less adaptable to the total recycle system concept.
Procedures used for analysis of the various parameters in the
waste waters were taken, for the most part, from standard ana-
lytical reference texts (EPA, 1971; APHA et al, 1971). Chromato-
graphic methods were developed as required to measure specific
organic constituents of the waste streams.
In all cases, waste water was sampled during normal operation of
the units producing the waste water. Sampling was designed to
obtain daily representative samples. Where required, multiple
daily samples were taken and composited.
The principal objective of the characterization was to determine
if any parameters or contaminants were present that would affect
the operation of the electrodialysis-reverse osmosis (ED-RO)
recycle system. Such contaminants as calcium, magnesium and
sulfate ions, silica, suspended solids, organic acids and bases,
and some nonpolar hydrocarbons could be expected to foul the
membranes used in the ED-RO recycle system. If these types of
contaminants are present in the waste waters, it is expected that
pretreatment of the brine would be required.
"Methods for Chemical Analysis of Water and Wastes", Environmental
Protection Agency, Water Quality Office, Analytical Quality
Control Laboratory, Cincinnati Office, 1971.
"Standard Methods for the Examination of Water and Wastewater",
Thirteenth Ed., American Public Health Association, Washington,
D.C. APHA, AWWA and WPCF, 1971.
-------
STREAM 1 - CHARACTERIZATION
Stream 1 is an organic production waste water stream containing
nitrogenous organic compounds. The summary of the inorganic
constituents, organic constituents, and trace metal concentra-
tions of Stream 1 are given in Table 1.
The results indicated that the waste water might need treatment
for removal of silica, amines, and possibly calcium, magnesium,
and sulfate ions before being processed by the ED-RO recycle
system. Approximately 70 percent of the total organic carbon
(TOC) and 83 percent of the organic nitrogen were accounted for
by gas chromatographic (GC) analysis. It is known, however, that
higher molecular weight diamines that cannot be determined by GC
analysis are present in the waste water.
STREAM 2 - CHARACTERIZATION
Stream 2 is a petrochemical production waste water. The summary
of the inorganic constituents, organic constituents, and trace
metals concentrations of Stream 2 are given in Table 2.
Approximately 95 percent of the total organic carbon (TOC) was
accounted for by the benzene and ethylbenzene found by the gas
chromatographic analysis. The results indicated that the waste
water will probably have to be treated for removal of the
aluminate ion, the aromatic hydrocarbons and possibly the silica.
-------
Table 1. INORGANIC AND ORGANIC CONSTITUENTS - STREAM 1
(Concentrations in mg/1)
NaOH
NaOH
Total Dissolved Solids
(TDS)
Suspended Solids
Ammonia-Nitrogen
Inorganic Carbon (1C)
Silica
Chloride ion
Sulfate ion
Total Organic Carbon
(TOC)
Organic Nitrogen
Calcium
Magnesium
Iron
Cu, Zn, Mn, Cr
Ni
Al
Minimum
12.3
2,426
1,653
2,380
18
30
8
10
74
27
903
1,110
Maximum
13.2
21,646
12,160
15,770
84
300
64
80
1,015
40
3,843
3,460
Average
12.6
10,550
5,190
6,990
37
157
24
45
433
35
1,824
2,046
20
8
1.1
0.2
0.4
0.8
-------
Table 2. INORGANIC AND ORGANIC CONSTITUENTS - STREAM 2
(Concentration in mg/1)
Parameter
PH
Total Alkalinity
as NaOH
Total Dissolved Solids
(TDS)
Suspended Solids
Inorganic Carbon
Silica
Chloride Ion
Sulfate Ion
Color-APHA units
Aluminum Ion
Total Organic Carbon
(TOC)
Total Oxygen Demand
(TOD)
Calcium
Magnesium
Iron
Cu, Zn, Mr, Cr, Ni
Minimum
11.3
1,600
20,800
2
2
nil
10,075
nil
20
325
21
74
Maximum
12.8
9,680
62,500
58
968
8.4
29,500
nil
90
920
197
329
Average
12.0
4,947
42,320
31
166
4.7
21,400
nil
45
680
86
126
7.6
1.0
0.7
1.6
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SECTION 5
STREAM 1. TOTAL RECYCLE SYSTEM
Stream 1 was selected to be studied in. detail for the applic-
ability for recycle as shown in Figure 1. The objective was to
investigate the required combination of unit operations that
would approach a total recycle system. The reverse osmosis and
electrodialysis operating as a hybrid to produce reusable water
and a concentrated brine suitable for recycle is the principal
ionic management of the advanced treatment system. Unit opera-
tions preceeding the RO-ED system are necessary for removal of
any constituent that interferes with the operation of the RO or
ED units, and if possible, for the recovery of valuable constit-
uents to improve tne economics of the recycle system.
A. PRETREATMENT STUDIES
The characterization of Stream 1 indicated that at least four
steps would be necessary before the waste water could be treated
by the reverse osmosis-electrodialysis process. These steps are
ammonia removal and recovery, amine removal and recovery, neutral-
ization and possibly silica removal. Ammonia removal is necessary
to prevent the ammonia from appearing in the product water or
the brine, and recovery is desirable. The amines must be removed
because they may cause fouling of the membranes and recovery is
highly desirable because of their high unit price value. Neutral-
ization is required because the pH requirement of the reverse
osmosis membrane. Silica may have to be removed to prevent
membrane fouling.
Ammon i a Remo va1
Methods for removal and recovery of ammonia from waste waters are
reviewed in Appendix C. The liquid membrane process and ion ex-
change on clinoptilolite were tested on Stream 1 and the results
are included in Appendix C. Neither of these two methods were
found attractive. Conventional stream stripping of the ammonia
was used for the purpose of cost estimating the total process.
Amines Removal and Recovery: Carbon Adsorption
Nine carbons were evaluated to select the best carbon for the
adsorption of the amines. A standard isotherm was run with each
carbon using waste water, as received, with no pH adjustment.
10
-------
Increasing weights of each carbon were added to 100 mis of
waste water in bottles that were shaken in a temperature
regulated water bath for 24 hours at 25ฐC. The samples were
filtered and analyzed for total organic carbon and an adsorption
isotherm was plotted for each carbon.
Figure 2 shows a comparison of the results for three carbons and
the results for all the carbons are summarized in Table 3. The
carbon with the largest capacity at 1000 mg/1 was Westvaco WV-G,
12 x 40 mesh. Subsequently this one was used in the carbon bed
tests.
The carbon bed tests were run using four carbon columns operated
in series. A variable speed peristaltic pump was used to feed
the beds and a three-way solenoid was placed in the line after
each column. An electrical timer controlled the solenoids such
that after a 19-minute period, the solenoid would open for 15
seconds and divert a 20 ml. sample to a test tube in the SMI
model 1205 fraction collector. Each column was sampled sequen-
tially from first to last and the sampling cycle started again.
The fraction collector advanced every 18 minutes so that an empty
test tube was always ready for the sample. The collected samples
were analyzed for total organic carbon. A few samples were also
analyzed for the amines by gas chromatography.
Table 4 summarizes the conditions for the bed tests. The first
cycle was run at 22 ml/min. (1.06 gpm/sq.ft.) during loading and
44 ml/min. (2.12 gpm/sq.ft.) during regeneration of the carbon.
The balance of the cycles were run with these rates reversed.
Figure 3 gives the results from the last cycle. The plots for
the other three cycles were similar. Table 5 presents a summary
of the results.
After the first cycle of loading and regeneration, no further
significant change in capacity or TOG recovered was noted.
Further bed tests were run using one large carbon bed. The
objective of this test was to provide a large amount of pre-
treated waste water for the electrodialysis-reverse osmosis
tests. The column was 7' x 4" O.D. The carbon bed was 6.5'x
3.5" I.D. The bed volume was 11 liters and the weight of the
Westvaco WV-G carbon was 4400 grams.
The regeneration step was followed closely on the third cycle.
Figure 4 is a plot of the results. The regeneration stream was
divided into three cuts; the first cut included the void volume
of the bed and neutralization of the caustic by the acid. This
cut was basic and the TOC was that of the original feed. This
cut could be recycled to the feed. The second cut was the pro-
duct cut containing 90 percent of the TOC and was acidic. The
TOC concentration was approximately 1.5 percent or approximately
3.0 percent amines. The last cut was low in TOC and high in acid
11
-------
100
80
- 60
m
mg TOG
g Carbon
40
20
10
At 25ฐC
Westvaco Carbons
*200 400 600 1000
TOC Residual, mg/1
1500
Figure 2. ADSORPTION ISOTHERMS - STREAM 1
-------
Table 3. COMPARISON OF COMMERCIAL ACTIVATED CARBONS
FOR AMINES ADSORPTION - STREAM 1
Initial Concentration 1600 mg/1 TOC
Exhaustion Capacity
at 25ฐC
mg TOC/gram carbon
Activated Carbon
Westvaco WV-G
Barneby Chaney SC
Westvaco WV-L
Hydrodarco 3000
Westvaco WV-W
Barneby Chaney PC
Witco 517
''f'?'
Filtrasorb 400
Filtrasorb 300
90
84
72
68
62
60
56
52
42
13
-------
Table 4. CARBON BED TEST CONDITIONS - STREAM 1
Feed
Carbon
Columns
Bed Volume
Total Bed Height
Weight of Carbon
Cross Sectional Area
Temperature
Pressure
Regenerant
Regenerant Volume
Unneutralized Stream 1
Westvaco WV-G, 12 x 40 mesh
(4) 4-1/2 foot x 1 inch i. d,
(4) x 690 = 2760 mis
18 feet
1140 grams
5.1 sq cm
25ฐC
4.5 inch Hg
2N HC1
2 bed volumes
14
-------
1.0
.8
o
u
CJ
.6
.4
.2
1525 TOG
I
I
10 15 20
Service Time, hours
25
30
Figure 3. CARBON COLUMN TEST - CYCLE 4
-------
Table 5. CARBON BED TEST RESULTS - STREAM 1
Feed, TOC = 1525 mg/1
Regenerant = 2N HC1 - 2 Bed Volumes
Cycle
Loading Rate, gpm/sq. ft 1.06 2.12 2.12 2.12
TOC Adsorbed, g 52.9 53.1 49.3 52.7
Capacity, mg TOC/g Carbon 47 47 43 46
Regeneration Rate, 2.12 1.06 1.06 1.06
gpm/sq. ft.
TOC Recovered, g 39.1 49.4 48.3 48.5
TOC Recovered, % 74 93 98 93
16
-------
Large Column, 3rd Cycle
Product Cut
0.8 Bed Volumes
tn
U
O
28,000
24,000
20,000
16,000
12,000
8,000
4,000
Recycle to
feed
0.7 Bed Volumes
I Recycle
I to acid
Tank
I
I I
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Bed Volumes 2N HC1 Passes
Figure 4. REGENERATION - ACTIVATED CARBON - STREAM 1
-------
and could be recycled to the acid tank. The column was finally
washed with a half bed volume of water to flush out the acid
before the feed was restarted. The water wash also could be
recycled to the acid tank.
Silica Removal
The first electrodialysis-reverse osmosis test using pretreated
Stream 1 was terminated shortly after starting because of fouling
of the electrodialysis and reverse osmosis membranes. Analysis
indicated the fouling substance consisted largely of amorphous
silica.
A literature survey indicated the best method for removing
silica from water was by adsorption on activated alumina. This
was described in a report by Bell, et al, (1968) .
An adsorption isotherm was run to determine the equilibrium
capacity of the alumina for the silica. Two different mesh
ranges of alumina were used. Figure 5 shows the isotherm results.
The capacity of the 80-200 mesh alumina was 20 mg. silica/g.
alumina, significantly higher than the capacity for the 8-14
mesh.
A column bed test was then run. A small plexiglass column was
filled with 129 grams of 30-40 mesh Alcoa F-l activated alumina.
About 24 liters (190 bed volumes) of synthetic Stream 1 con-
taining 102 mg/1 silica was passed through the bed when break-
through occurred. The breakthrough capacity was 20 mg of silica
per gram of alumina. This same alumina was used in a three
column set-up to remove the silica from the feed for the electro-
dialysis-reverse osmosis experimentation.
The alumina was regenerated with 2 bed volumes of 1 N sodium
hydroxide. It was indicated qualitatively that the alumina also
removed some of the trace amines and that they could be collected
in a concentrated fraction during regeneration. The alumina
pretreatment will be used as required to remove the silica.
B. REVERSE OSMOSIS AND ELECTRODIALYSIS STUDIES - STREAM 1
The electrodialysis unit used for these experiments was an Asahi
Chemical Industries Model SV-5 laboratory electrodialysis unit.
Figure 6 describes the SV-5 unit and operating parameters. In
the SV-5 unit, the feed is pumped into the dilution recycle tank.
The dilution recycle is pumped through the dilution half cells
within the electrodialysis stack. There the anions and cations
Bell, G. R. at al, Office of Saline Water Research and Develop-
ment. Progress Report No. 286, 1968.
18
-------
x e
O - 80-200 Mesh
D - 8-14 Mesh
.1
C0 = 75 mg/1 Silica
Temperature = 25ฐC
_L
I I I
I
I
4 6 8 10 20 40
Residual Silica, mg/1
I 'I I
60 80 100
Figure 5. SILICA ADSORPTION ON ACTIVATED ALUMINA
19
-------
Feed
1 ฃ
+
Dilution
Half
Cell
Brine
Half
Cell
Product
I
r
Cathode
Rinse
Brine
Production
Operating Parameters:
Membranes
Active membrane area
Linear, velocity-dilution .
Stack size
Brine recycle rate . . . .
Anode rinse flow rate. . .
Cathode rinse flow rate. .
Standard reinforced anion &
0.75 dm2
15 cm/sec
5 cell pairs
0.3 gpm 2
100 .mVmin/amp-dit^
100 ml/min/amp-dm
cation -Asahi Chem.Ind.
Figure 6. SV-5 ELECTRODIALYSIS UNIT
-------
are transported to the adjacent brine half cell compartments
under the influence of the direct current potential generated by
the anode and cathode. The depleted dilution recycle then re-
turns to the tank. The brine flow is recycled and the increase
in volume caused by the transport of water and brine from the
dilution compartment is bled off as the brine production. The
depleted product water is bled off the dilution recycle tank.
The cathode is rinsed with HC1 to remove the hydrogen gas and
caustic that is produced at the cathode. This stream is recycled
and replaced when depleted. The anode is rinsed with NaCl to
sweep out the chlorine and acid produced at the anode. This
stream is not recycled to prevent deterioration of the end mem-
brane from chlorine exposure.
A Universal Water Corporation laboratory model reverse osmosis
unit designed for [small flat] membranes was modified for the use
of Dow hollow fine fiber reverse osmosis cartridges. The car-
tridge used was a low pressure Dowex XFS-4167.07 Permeator with
a nominal capacity of 250 GPD. Figure 7 describes the equipment.
Electrodialysis Preliminary Evaluation
Stream 1, neutralized to pH 7, but untreated with carbon adsorp-
tion was used as feed to determine the extent of the problems
encountered with the electrodialysis equipment. The potential
across the stack was held at 3 volts and the current density was
allowed to vary.
The experiment was run for 12 hours with the brine reaching a con-
centration of 10.4 percent NaCl. The dilution stream was replaced
with more feed and the run continued for 12 more hours. The final
concentration was 12.8 percent NaCl (Figure 8). The organics were
concentrated in the brine stream. The TOC was concentrated from
1235 mg/1 in the feed to 5,144 mg/1 in the brine and only 185 mg/1
in the dilution stream. The organic nitrogen of 1180 mg/1 in the
feed was concentrated to 5,100 mg/1 in the brine and only 112 mg/1
in the dilution stream. The stack was dismantled and the cation
membranes were found to be fouled. Analysis of the dilution and
brine streams indicated that the amines were being transported.
However, the heavier amines must have been trapped in the mem-
branes. Attempts to regenerate the membranes by soaking in
caustic failed.
The electrodialysis apparatus was then tested on a pretreated
Stream 1 feed with a composition shown in Table 6. The dilution
and brine recycle tanks were filled with 2 liters of feed and
then the unit was operated until equilibrium was reached, in
10 hours. No additional feed was added. Figure 9 shows the
results of the test. A concentration of 15.5 percent NaCl was
considered to be satisfactory level.
21
-------
200 psi N2
NJ
Hollow Fine Fiber
Reversis Osmosis Module
-*.
I
G-
High Pressure
Pump
Feed
Jug
Product
or
Permeate
Brine or
R.O. Reject
Back
Pressure
Valve
Figure 7. REVERSE OSMOSIS EQUIPMENT
-------
140,000
130,000
120,000
110,000
100,000
90,000
^Hi
op 80,000
K
- 70,000
^^
g 60,000
50,000
40,000
30,000
20,000
10,000
0
D - Brine Recycle
- Dilution Recycle
J I
I I
I I I I I I I
0 246 8 10 12 14 16 18 20 22 24 26 28
Time, hours
Figure 8. ELECTRODIALYSIS OF NEUTRALIZED
UNTREATED STREAM 1
23
-------
Table 6. PRETREATED AND NEUTRALIZED STREAM 1
WASTE WATER COMPOSITION
pH 7
NaCl, mg/1 14,750
CaCl2, mg/1 59
MgCl2, mg/1 33
NH3-Nitrogen, mg/1 134
Total Carbon, mg/1 170
Inorganic Carbon, mg/1 13
Total Organic Carbon, mg/1 159
Organic Nitrogen, mg/1 107
24
-------
J-
o
O - Current
A - Feed
D - Brine
4567
Time, hours
9 10
Figure 9. ELECTRODIALYSIS OF PRETEXTED STREAM 1
25
-------
As the current density, measured in amperes per square decimeter
(amp/sq.dm.), is increased through the system of membranes and
solutions, the rate of electrical transport increases. A current
density will be reached at which the concentrations of the electro-
lytes at the membrane interfaces on the depleting sides will
approach zero. At this density, usually called the limiting
current density, H and OH~ ions from the ionization of water
will begin to be transferred through the membranes. The presence
of layers of almost pure water at the membrane surfaces causes
the resistance of the membrane cells to be high, and is accompa-
nied by a higher increase of voltage. Figure 10 is the limiting
current density plot for the run. The plot indicates that the
current density could have been operated a little higher (2.75
amp/sq.dm.) than the 2.4 amp/sq.dm. at which the run was made.
To simulate the operation of the combined ED-RO unit, a run was
made in which the dilution stream from ED was processed in the RO
unit, then the reject from RO was combined with the feed to the
ED unit.
The operation was the same as the previous run, except that the
feed was added continuously to the dilution recycle tank and the
dilution product was bled off. A small amount of brine was also
removed continuously from the brine recycle.
The dilution recycle flow was set at 0.5 GPM and the brine recycle
was '0.3 GPM. The stack voltage was 3.0 volts and the initial
current was 1.8 amp/dm2. At the start, 2500 mis. of feed was
placed in the dilution recycle tank and 1300 mis. of feed was
placed in the brine recycle tank. Initial feed NaCl concentra-
tion was 1.41 percent. The feed was added continuously to the
dilution recycle tank when the dilution recycle concentration
reached 4000 mg/1 NaCl. The feed rate was 18 mls/min. The run
lasted 9i hours, during which time the dilution recycle stabil-
ized at 2400 mg/1 NaCl and the brine recycle increased to 8.6
percent NaCl.
The unit was shut down and the dilution recycle was transferred
to the reverse osmosis unit and processed. The reverse osmosis
reject concentration was 6760 mg/1 NaCl, which was mixed with
more electrodialysis feed and placed back in the electrodialysis
unit. The dilution recycle was now 1.067 percent NaCl. The unit
was restarted with the same brine recycle. When the dilution
recycle reached the 4000 mg/1 NaCl concentration, the feed was
started at 27 ml/min. The results of the runs are plotted in
Figures 11 and 12. The second run continued for 5 hours, during
which the dilution recycle stabilized at approximately 4000 mg/1
NaCl. The brine recycle reached 12.3 percent NaCl. The maximum
current density allowable was 2.18 amp/dm2 as indicated in the
limiting current density plot in Figure 13. No operational
problems were encountered during the experiment. Analyses of
grab samples during the run indicated the total organic carbon
26
-------
5.0_
X 4.5
o
(0
n 4.0
3.5
3.0
2.5
1.0
I
2.0
Stack Current, amps
3.0
2.0 2.5 3.0 3.5
Current Density, amps/dm2
4.0
4.5
Figure 10. ELECTRODIALYSIS OF PRETREATED STREAM 1 -
LIMITING CURRENT DENSITY
27
-------
u
(0
2
- Brine Recycle
- Dilution Recycle
4567
Time, hours
9 10
Figure 11. CONTINUOUS ELECTRODIALYSIS OF PRETREATED
STREAM 1 FEED
28
-------
a 70,000
- Brine Recycle
- Dilution Recycle
2 3 '
Time, hours
Figure 12. CONTINUOUS ELECTRODIALYSIS OF PRETREATED
STREAM 1 PLUS RO REJECT MIXTURE
29
-------
l.Or-
H
nJ
O
0.8
0.7
ol 0.6
a,
CO
0.5
0.4
2 0.3
-P
c
I 0.2
0.1
0
0
2.18 amp/dm'
1.0
2.0
3.0
Current Density, amp/ dm
Figure 13. LIMITING CURRENT DENSITY OF COMBINED
PRETREATED STREAM 1 AND RO REJECT STREAM
30
-------
and the ammonia nitrogen was transported and concentrated in the
brine. The reverse osmosis membrane also rejected the TOG and
the ammonia nitrogen.
Reverse Osmosis Tests
The electrodialysis dilution recycle is feed for the reverse
osmosis unit in the total recycle system concept. Several ex-
periments were made in connection with the electrodialysis
evaluation experiments. The objectives of these experiments
were to determine operating conditions for the reverse osmosis
unit to produce less than 500 mg/1 NaCl product at 200 psi, and
test for the possibility of membrane fouling. The results of
the runs are summarized in Table 7. The results indicate that:
Satisfactory quality product water can be produced from the
reverse osmosis unit from 4000 mg/1 NaCl feed at 200 psi and a
50-50 product-reject split. The ammonia-nitrogen, TOC and
organic-nitrogen are all concentrated in the reverse osmosis
reject, and no fouling of the membrane was indicated.
Evaluation of Combined Electrodialysis-Reverse Osmosis Treatment
of Stream 1 " ~~~~
The objective of this experiment was to combine the previously
evaluated electrodialysis and reverse osmosis units and to op-
erate the combined units continuously on pretreated neutralized
Stream 1 to determine the necessary design parameters.
A schematic of the combined laboratory units is given in Figure
14. Neutralized pretreated Stream 1 [1] is mixed with the reject
[6] from the reverse osmosis unit. This stream [2] is fed into
the dilution recycle loop. A portion of this stream [4] is fed
to the reverse osmosis unit. It is expected that this stream
will have a concentration of 4000 mg/1 NaCl. Because the electro-
dialysis unit was not well matched to the reverse osmosis unit in
flow capacity, a large portion of the reverse osmosis product [7]
and the reject [8] was recycled and mixed with the dilution re-
cycle [4] to form the reverse osmosis feed [91. A portion of
the product flow [5] is taken off continuously. A portion of
the brine recycle is taken off as brine product [3] . The feed
flow [1J should be exactly equal to the sum of the brine [3] and
the reverse osmosis product [5].
Prior to the run, a standard brine with a sodium chloride con-
centration of 14,000 mg/1 was run under the same conditions as
the actual run. The feed rate was 32 ml/min. The brine pro-
duction rate was 3 mls/min. The reverse osmosis product rate was
29 ml/min. The dilution stream NaCl concentration was 4000 mg/1.
The reverse osmosis reject NaCl concentration was 7900 mg/1. The
reverse osmosis product contained 640 mg/1 NaCl. The reverse
osmosis split was 50 percent product-50 percent reject. The NaCl
rejection was 98.8 percent. The operating current density was
31
-------
Table 7. REVERSE OSMOSIS EVALUATION
Electrodialysis Dilution Recycle Feed
200 psi
NaCl, mg/1
Peed Flow, ml/rain.
Product NaCl, mg/1
Product Flow, ml/min.
Reject NaCl, mg/1
Reject Flow, ml/min.
Split
Run*
1
4030
704
486
356
7510
348
51 - 49
2
4210
834
476
404
7411
430
48 - 52
3770
709
503
353
6760
356
50 - 50
*Run 1 - E.D. Recycle from Pretreated Stream 1.
Run 2 - E.D. Recycle, Stream 1.
Run 3 - E.D. Recycle from Continuous Run.
32
-------
00
u>
Neutralized Feed
Reject
Brine Recycle
Brine
Electrodialysis
Dilution
Recycle
Revers
Feed
2 Osmosis
.Product
Water
Permeate
Reiect
Figure 14. ED - RO INTEGRATED SYSTEM
TREATMENT OF STREAM 1
-------
3.2 amps/dm2. The limiting current density was found to be 3.5
amps/dm2. No operational difficulties were noted.
This run was terminated and the feed was switched to the neutral-
ized pretreated Stream 1, with composition similar to that given
in Table 6. The operating conditions for the experiment are
shown in Table 8. The limiting current density for this run was
1.8 amps/dm2, and it was operated for 20 hours.
Figure 15 shows the changes that occurred in the critical op-
erating parameters during the run. The current density had to be
continually adjusted to maintain a value of 2.4 amps/dm2. As is
noted in Figure 15, the current density continued to decrease.
The adjustment back to 2.4 amps/dm2 caused the voltage to increase,
While this was occurring, the reverse osmosis unit was plagued
with decreasing product water recovery. Also during the run, the
dilution NaCl concentration increased from 4000 mg/1 to 6700 mg/1.
The brine started at 146,000 mg/1 NaCl and decreased to 136,000
mg/1. The reverse osmosis product NaCl concentration increased
from 500 mg/1 to 815 mg/1.
After 20 hours, the units were shut down because of the operation-
al problems, and the electrodialysis stack was dismantled.
A thick, oily film was found on the anion membranes. The material
was collected for analysis. The analysis of the material in-
dicated that it was 16.8 percent silicon or 36 percent silicon
dioxide. The pretreated feed was found to contain 69 mg/1 silica.
The reverse osmosis reject stream contained 130 mg/1 silica.
It was apparent that the silica in the feed was fouling both the
electrodialysis membrane and the reverse osmosis membrane. Also
the operating current density was much lower than it was during
the standard run. The feed will also have to be treated to
remove silica.
Continuous Electrodialysis-Reverse Osmosis Run with Silica
Removed
Neutralized carbon treated Stream 1 was treated with activated
alumina to remove the silica. The analysis of the feed was the
same as the previous run, except that the silica concentration
was now 10 mg/1. The operating conditions were the same as the
previous run. The limiting current density for this solution was
1.7 amps/dm2.
For a feed rate of 28 mg/min., a product from the RO unit of
21 ml/min. and a brine product rate of 3 ml/min. were obtained.
The reject of RO was 8700 mg/1 NaCl and the product was 400 mg/1
NaCl. The brine concentration of 14 percent NaCl was ten times
the concentration of the feed. The ED unit was operated at 0.74
34
-------
Table 8. ELECTRODIALYSIS - REVERSE OSMOSIS
COMBINED TEST, STREAM 1
Electrodialysis Unit:
Membranes
Stack Amps
Stack Volts
Cell Pairs
Feed Flow
Dilution Flow
Dilution NaCl
Dilution pH
Dilution Temperature
Brine Production
Reverse Osmosis Unit:
R.0. Membrane
Pressure
Feed Rate
Product Recycle
Rate
Reject Recycle
Rate
Split
Product Rate
- A&K 101 Asahi Chemical Ind.
- 1.6
- 7.3
- 10
- 30 ml/min.
-1.7 1/min.
- 4000 mg/1
- 7.1
- 26ฐC
- ^3 mls/min.
- Dowex XFS-4167.07 Permeator
- 200 psi
- 640 ml/min.
- 317 ml/min.
- 324 ml/min.
- 50 - 50
-27 ml/min.
35
-------
U)
CTv
Volts 4
cell pair
85
,80
75
,70
Amps
dm
10
15
20
25
50
40
30
% Recovery
of Product
Water
Hours
Figure 15. ED-RO COMBINED OPERATION - CRITICAL PARAMETERS - STREAM 1
WITHOUT SILICA REMOVAL
-------
volts per cell pair and a current density of 1.6 amps/dm2. Figure
16 plots the same critical operational parameter as shown in the
previous experiment. The experiment was run for 70 hours with no
operational difficulties.
The current density remained stable throughout all of the exper-
iment. The reverse osmosis recovery increased somewhat toward
the end of the run. Of greatest interest is the fact that the
operating current density was still much lower than that during
the standard run. The probable cause is the low level of amines
present in the feed. This emphasizes the need for near complete
removal of these compounds.
C. TOTAL RECYCLE SYSTEM DESIGN AND COST ESTIMATE
A flow diagram of the total recycle system of Stream 1 is given
in Figure 17, which includes a material balance and flow rates of
each stream. The ammonia removal step is not shown on the flow
sheet, and if required, its design is based on conventional steam
stripping.
A summary of the estimated capital and operating costs of the
total system is given in Table 9.
Details of the design and cost estimates of the unit operations
required for the total recycle of Stream 1 are shown in Appendix D.
37
-------
.80
.75
Volts '
cell pair
u>
00
Amps
dm2
I
50
40
30
Recovery
10
20
30
40
Hours
50
60
70
Figure 16.
ED - RO COMBINED OPERATION-CRITICAL PARAMETERS
STREAM-1, WITH SILICA REMOVAL
-------
OJ
vo
(Stream 1)
Waste Water
Organics - HC1
Recycle
4-5% Organics
Silica
Removal
2N-HC1
Carbon
Adsorption
HC1
Neutralization
-e^J
ion I
1.3 %
! 1.02 mgd [
fc ^ JNaCl~f4.5 %"i
j_ ,09 mgd j
Brine
Electrodialysis
Reverse Osmosis
Product
--iNaCl <500 ppra
il .93 mgdj
T --
Ib./hr.
ฉ
TOG
NaOH
Silica
HC1
NaCl
H2O
Total
600
3,000
21
300
343,600
374,521
630
3,000
21
3,100
402,940
409,721
2
9,800
162,600
172,400
568
70,900
71,466
_.
3,000
1,108
8,108
30
21
5,900
417,899
423,850
30
4
8,720
720,000
720,720
544
72
5,700
34,000
39,700
.ป .
3,020
678,000
681,020
_ซ-
3,870
294,000
296,870
^ MM
150
384,000
384,150
Figure 17- TOTAL RECYCLE SYSTEM - STREAM 1
FLOW DIAGRAM AND MATERIAL BALANCE
-------
Table 9. COST FOR TOTAL RECYCLE SYSTEM - STREAM 1
1975 Dollars
Capital Cost;
Ammonia Removal CSteam Stripping) $1,156,000
Carbon Adsorption 2,330,000
Neutralization 87,000
Silica Removal 261,000
Electrodialysis-Reverse Omosis 3,115,550
Total $6,949,550
Operating Cost;
Ammonia Removal $ 300,000
Carbon Adsorption 2,358,000
Neutralization 1,900,000
Silica Removal 87,400
Electrodialysis-Reverse Osmosis 646,300
Tฐtal $5,291,700 $/yr
40
-------
SECTION 6
STREAM 2. TOTAL RECYCLE SYSTEM
Stream 2 contains 4.2 percent total dissolved solids. It was
selected to study the electrodialysis-reverse osmosis total
recycle, as it represents the highest concentration that can
possibly be treated with such a system.
A. PRETREATMENT STUDIES
The characterization of Stream 2 indicated that at least two
steps would be necessary before the waste water could be treated
by the electrodialysis-reverse osmosis process. These steps are
aluminate removal and recovery (neutralization) and organic
carbon removal.
Aluminate Removal-Neutralization
The neutralization of Stream 2 caused the precipitation of the
aluminate ion in the form of aluminum hydroxide. Precipitation
starts at a pH of 11.2. Analysis of the supernatant after
adjustment to pH 7.0 indicated less than 1 mg/1 of aluminun ion
present. Therefore virtually all the aluminate is removed at pH
7. The characterization indicated that Stream 2 had an average
alkalinity of 4950 mg/1 as sodium hydroxide, a 0.124 N sodium
hydroxide solution. Therefore 0.124 equivalents Of hydrochloric
acid per liter would be required for neutralization or 10.3
gallons of concentrated HC1 (12 N) per 1000 gallons of Stream 2.
The suspended solids formed during neutralization must be removed
and concentrated. The concentrated aluminum hydroxide may then
be converted to aluminum chloride for reuse in the process or
sold as a coagulant. The average suspended solids formed during
neutralization of Stream 2 is 1500 mg/1.
Gravity settling tests were run on the sludge to determine the
design parameters for a gravity settler. Varying concentrations
of sludge were placed in one liter graduated cylinders. A 4 rph
stirrer was placed in each cylinder and the interface level was
recorded at various time intervals. The sludge settles very
poorly. Addition of varying concentrations of Purifloc A-23
flocculant to the sludge in a standard jar settling test produced
no improvement in settling rate or decrease in sludge volume.
The range of flocculant concentration was from 0.3 to 25 mg/1 of
A-23. The addition of up to 200 mg/1 of ferric chloride also had
no significant effect on the settling.
41
-------
Figure 18 is a plot of the settling velocity versus initial
solids concentration for the gravity settling tests. Figure 19
is a plot of solids flux versus solids concentration. From this
graph using the Yoshioka method as described by Vesilind (1974),
the minimum solids flux can be determined for any desired under
flow concentration and the surface area for the settler can be
determined if the daily flow is known. Table 10 presents the
design solids flux and settler surface area for various underflow
sludge concentrations. The design flow was 1 MGD, the initial
solids concentration was 1500 mg/1. This information will be
used to design a gravity settler for Stream 2.
A comparison was made of various granular activated carbons to
determine which has the greatest capacity for the organics
(Mainly benzene) in Stream 2. This was done by adding 0.05 grams
of each carbon and mixing with 250 mg/1 of neutralized Stream 2.
The carbon with the greatest capacity was selected for further
evaluation. The results are shown in Table 11. The best carbon
was Witco 517.
An adsorption isotherm was run at 25ฐC with Witco 517. A syn-
thetic Stream 2 sample was used. Figure 20 presents the isotherm
obtained. Equilibrium capacity was determined to be 160 mg of
TOC per gram of carbon.
A carbon bed test was run using actual Stream 2 waste water. A
1-in. I.D. glass column was filled with 175 grams of prewashed
Witco 517 to a height of 2.3 feet. The bed volume was 690 mis.
The feed rate to the column was 42 mls/min or 2.0 gpm/ft2.
Stream 2 waste water was neutralized, settled and the decant was
fed to the column. The effluent from the column was analyzed
periodically for benzene and TOC. The benzene concentration of
the feed was below average for the waste because benzene was lost
to the air during the neutralization and settling step. Figure
21 is a plot of the breakthrough curve. Breakthrough was achieved
at 330 hours of operation and exhaustion took place at 370 hours.
The average feed benzene concentration was 29 mg/1. The break-
through capacity was 134 mg benzene per gram of carbon. The
exhaustion capacity was 147 mg benzene per gram carbon which is
higher than the isotherm capacity of approximately 100 mg of
benzene per gram of carbon.
The average TOC of the feed during the test was 60 mg/1 and the
average TOC of the effluent was 18 mg/1. There is apparently a
small amount of TOC which will not adsorb on the carbon. A carbon
bed will be designed to treat Stream 2 before electrodialysis-
reverse osmosis treatment using this data. Regeneration of the
carbon will be done thermally.
Vesilind, P. A. Treatment and Disposal of Wastewater Sludge,
Ann Arbor Science Publishers, Inc., Ann Arbor, Michigan, 1974
42
-------
P
m
-P
-H
o
o
t-i
(U
On
C
H
H
-P
-P
Q)
CO
I
I
I
I
I
1000 2000 3000 4000 5000 6000
Solids Concentration, mg/1
Figure 18.
GRAVITY SETTLING - ALUMINUM HYDROXIDE
SLUDGE - STREAM 2
43
-------
"O
en
X
O
Cfi
.1
J
I
I
1000 2000 3000 4000 5000
Solids Concentration, mg/1
6000
7000
Figure 19. GRAVITY SETTLING - ALUMINUM SOLIDS FLUX -
STREAM 2
44
-------
Table 10. GRAVITY SETTLING DESIGN DATA
Initial Solids Concentration. 1500 mg/1
Overflow
Concentration
of Underflow,
mg/1
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
Concentration
Solids Flux,
Ib./ft. Vday
2.87
2.45
2.25
2.06
2.00
1.95
1.89
1.84
... 10
Area,
ft.2
4,359
5,106
5,560
6,073
6,255
6,415
6,619
6,800
LlXjlA
mg/1
Rate
Overflow,
mgd
0.498
0.373
0.299
0.249
0.213
0.186
0.166
0.149
45
-------
Table 11. COMPARISON OF ACTIVATED CARBONS
REMOVAL OF ORGAN1CS FROM STREAM 2
C0 = 50 mg/1 TOC (Total Organic Carbon)
0.05 gms carbon/250 mis waste water
Adsorptivity,
Carbon mg TOC/g C
Witco 517 84
Calgon FS-300 76
Barneby Chaney - PC 72
Westvaco - WV-G 67
Westvaco WV-W 61
Hydrodarco HD-3000 55
Calgon FS-400 42
46
-------
400
2,00
u
c 100-
&
8.0-
60
40
U
o
20-
10
Witco-517
Synthetic Stream #2
25ฐC
\ I
4 6 8 10 20
Residual TOG, mg/1
I
I C0 = 92 rag/1
I jn
40 60 80 100
Figure 20. CARBON ADSORPTION ISOTHERM - STREAM 2
-------
CO
40r-
30
c 20
Q)
N
0)
10
250
I
500
750 1000
Bed Volumes
1250
1
1500
Figure 21. CARBON COLUMN TEST - STREAM 2
-------
B. ELECTRODIALYSIS-REVERSE OSMOSIS STUDIES - STREAM 2
The electrodialysis unit used for these experiments was an Asahi
Chemical Ind. Model SV-4 laboratory unit. This unit is larger
than the SV-5 used to study Stream 1. it has 10 cell pairs with
an active membrane area of 2 dm2 as compared to 5 cell pairs of
0.75 dmz active membrane area for the SV-5 unit.
The reverse osmosis equipment was the same as used in the evalua-
tion of Stream 1 treatment. The SV-4'unit was more closely
matched to the reverse osmosis unit in capacity than the SV-5
unit used previously.
Because of the high concentration of NaCl in Stream 2, 4.5 per-
cent NaCl, the units were first tested with a standard 4.5 percent
NaCl solution to define the operating parameters. The E.D. unit
operated at 0.58 volts/cell pair, and a current density of 2.5
amps/dm2 producing a dilution stream of 4900 mg/1 NaCl and a brine
stream of 14.3 percent NaCl. The current efficiency was 87.4 per-
cent and the limiting current density was 3.65 amps/dm2. The RO
unit was operated with a 4000 mg/1 NaCl brine at 97.4 percent
rejection and 50 percent product recovery. The NaCl concentration
in the reject was 7400 mg/1 and the product concentration was
240 mg/1.
Continuous ED-RO Operation on Pretreated Stream 2
The electrodialysis unit was operated to produce a dilution stream
of 9000 mg/1 NaCl, which was fed continuously to the RO unit.
The reject from the RO unit was 1.5 percent NaCl and a product
water of less than 500 mg/1 NaCl was obtained. This run was
continued except that the dilution concentration was lowered to
approximately 6000 mg/1. The same feed was used. The experi-
ment was allowed to run for 120 hours. The results are given in
Table 12. Figure 21 is a plot of the critical operating para-
meters. Table 13 presents a detailed analysis of the various
streams.
The operation of the units for 120 hours was uneventful. The
current density was close to the 2.05 amp/dm2 obtained during
the standard run. The current efficiency continued to decrease
throughout the run due to a steady decrease in brine production
possibly from leakage. Inspection of the membrane showed no
fouling or scaling. The calcium and magnesium ion present in the
feed were transported to the brine along with the sulfate ion.
Only traces of these ions showed up in the reverse osmosis product.
C. TOTAL RECYCLE SYSTEM DESIGN AND COST ESTIMATE
A flow diagram of the total recycle system of Stream 2 is given
in Figure 23, which includes a material balance and flow rates
of each stream. Centrifugation of the underflow of the gravity
49
-------
Table 12. CONTINUOUS ELECTRODIALYSIS-REVERSE OSMOSIS
RUN PRETREATED, STREAM-2 LOW DILUTION
CONCENTRATION RESULTS
Electrodialysis Unit;
Cell pairs
Feed NaCl
Feed Rate
Dilution Recycle Rate
Dilution Temperature
Brine Production Rate
Dilution NaCl
Brine NaCl
Current Density
Volts/cell pair
Reverse Osmosis Unit;
Reverse Osmosis Pressure
Feed Flow
Feed pH
Product Flow
Reject Flow
Reject NaCl
Product NaCl
Recovery
NaCl Rejection
10
41,800 mg/1
29 ml/min.
8.0 1/min.
24.0ฐC
7.3 ml/min.
4,700 mg/1
146,000 mg/1
1.95 amp/dm2
0.52
195 psi
42 ml/min.
6.0
23 ml/min.
19 ml/min.
7,850 mg/1
140 mg/1
55%
97.9%
50
-------
90
0.70
Volts/cp
A
0.60
0.50
o
Amp/dm2
20
40
60
Hours
80
100
80 %
Current
Eff.
70
60
50 %
Recovery
R.O.
product
30
120
Figure 22. CONTINUOUS E.D.-R.O. PRETREATED
STREAM 2
51
-------
Ul
K)
Table 13. CONTINUOUS ELECTRODIALYSIS-REVERSE OSMOSIS RUN WITH
PRETREATED STREAM 2
Average Analysis of Streams
Reverse Osmosis
Parameter Feed Dilution
NaCl, mg/1 41,800 4,700
Mg++, mg/1 0.2
Ca++, mg/1 8.5
Fe++, mg/1 0.07
S0if~~, mg/1 90
TOC, mg/1 12
Silica, mg/1 2
Brine Product Reject
146,000 140 7,850
<2 0.2
96 0.5
0.6 0.05
317 <1
4 1
-------
Stream 2,
Waste Wat
HCl
Neutralization
Centrifuge
Electrodialysis
Reverse Osmosis
Product
Water
Carbon
Adsorption
NaOH
HCl
A1+3
TOC
NaCl
H20
Total
SpGr
Flow
Units
Ib/hr
Ib/hr
Ib/hr
Ib/hr
Ib/hr
Ib/hr
lb/hi-
1.02
mgd
ฉ CD CD (4) (D (D ฉ (D CD ฉ ฉ ฉ
1,720
240
30
14,564
332,494
347,500
1.19
1.0
x
1,324
2,256
3,580
1.02
.0103
_ ,_
240
9
14,454
100,425
105,126
.030
ILI-.-,-
0
29
13,734
309,638
323,401
1.02
0.934
_
6
13,734
309,638
323,378
1.02
0.934
ซ.*_
8
3,340
75,313
788,444
1.02
0.227
-
1,700
164,922
166,622
1.01
0.480
_.-
1,790
380,210
382,000
1.01
1.10
__.
6
13,730
94,270
108,000
1.10
0.31
m
30
215,348
215,378
1.0
0.62
mL _ J
15,520
474,480
490,000
1.02
1.410
__ ___L
240
1
1,114
25,112
26,282
.076
Figure
23. TOTAL RECYCLE SYSTEM - STREAM 2
-------
settler is included as a concentration step and was designed based
on limited data obtained in the laboratory testing.
A summary of the estimated capital and operating costs of the
total system is given in Table 14.
Details of the design and cost estimates of the unit operations
required for the total recycle of Stream 2 are given in Appendix
E.
54
-------
Table 14. COST FOR TOTAL RECYCLE SYSTEM - STREAM 2
1975 Dollars
Capital Cost:
Neutralization and Solids Removal $ 250,000
Carbon Adsorption 1,017,000
Electrodialysis-Reverse Osmosis 7,903,000
Total $9,170,000
Operating Costs;
Neutralization and Solids Removal 123,700
Carbon Adsorption 407,000
Electrodialysis-Reverse Osmosis 1,763,000
Total $2,293,700 $/yr.
55
-------
SECTION 7
ECONOMIC EVALUATION BRINE AND POTABLE WATER REUSE
In order to make a cost comparison of the ED-RO system, calcul-
ations have been made on four different feed water salt concen-
trations. The study was further expanded by setting permeate
concentrations at 500 and 1500 mg/1 NaCl to demonstrate the
effect of product water quality on process economics. The cost
does not include pretreatment, as this varies with different
types of streams. Feed flow is 1 MGD.
Figure 24 shows the relationship of operating cost (including
capital amortization) per 1000 gallons of Stream 1 waste water
treated versus feed brine normality. The two product water
concentration restrictions are shown, as well as a theoretical
curve based on the higher current density achievable with an
ideal NaCl feed.
Making a change in perspective from a waste treatment plant to
one which produces process water, a similar cost analysis was
made. Figure 25 is a plot of cost (in dollars) per 1000 gallons
of permeate versus feed brine normality. There is a marked
difference at higher normalities between the Stream 1 waste and
the ideal NaCl brine.
To examine a salt production plant, another plot, Figure 26,
was made of cost per 1000 pounds of NaCl (produced as a 13-14
percent brine) versus feed brine normality. The three Stream 1
plots are combined in Figure 27.
56
-------
01
G
O
rH
25
O 20
o
o
o
-M
(0
15
-------
o
o
o
65^
60
55
n 50
o
rH
H 45
u
40
35
30
Q)
g 25
M
Q)
CM
20
15
10
5
- Permeate, 500 mg/1
A- Permeate, 1500 mg/1
Ideal NaCl
Solution
1 I I
0 .2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8 2.0
Normality of Feed Brine (NaCl)
Figure 25. COST OF ED-RO OF BRINE SOLUTIONS -
PRODUCTION OF PROCESS WATER
58
-------
w
tJ
G
o
o
o
(U
M
-------
m
o
Q
65
60
55
50
45
-40
35
30
25
20
15
10
5
0
- 500 mg/1 NaCl Permeate
A- 1500 mg/1 NaCl Permeate
$/1000 Ibs. NaCl
Recovered
$/1000 Gal.
Permeate
$/1000 Gal.
Water Treated
_L
I
I
I
I
I
_L
I
.2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8 2.0
Normality of Feed Brine (NaCl)
Figure 27. COST OF ED-RO TREATMENT OF STREAM-1
60
-------
BIBLIOGRAPHY
APHA, AWWA and WPCF, 1971 Standard Methods for the Examination
of Water and Wastewater, Thirteenth Ed., American Public
Health Association, Washington, DC.
Battelle-Northwest, "Wastewater Ammonia Removal by Ion Exchange,"
EPA-Water Pollution Control Series, No. 17010 ECZ 02/71, 1971,
Bell, G. R., J. C. Leineweber, and J. C. Yang, Office of_ Saline
Water Research &^ Development Progress Report No. 286, 1968.
Bober, T. W. and T. J. Dagon, Journal WPCF, 47(8), 2114-2129, 1975.
Calm, R. P. and N. N. Li, "Separation of Phenol from Waste Water
by the Liquid Membrane Technique", Separation Science, 9(6),
505-519.
EPA, 1971. Methods for Chemical Analysis gjf Water and Wastes
1971, Environmental Protection Agency, Water Quality Office,
Analytical Quality Control Laboratory, Cincinnati, Ohio.
Hewes, C. G. and R. R. Davison, AIChE Journal, 17(1), 141-147,
1971.
Hochhauser, A. M., "Concentrating Chromium with Luquid Surfactant
Membranes," Ph.D. dissertation, University Microfilms No.
74-20,365, Ann Arbor, Michigan, 1974.
Li, N. N. and A. L. Shrier, "Liquid Membrane Water Treating,"
Recent Developments in Separation Science, Vol. 1, CRC
Press, 1972.
McLaren, J. R. and G. J. Farquhar, "Factors Affecting Ammonia
Removal by Clinoptilolite," Journal of the Environmental
Engineering Division, 429, August 1973.
Mercer, B. W. L. L. Ames, W. J. Touhill, W. J. VanSlyke, and
R. B. Dean, "Ammonia Removal from Secondary Effluents by
Selective Ion Exchange," Journal WPCF, 42(2), part 2, 1970.
Schiffer, D. K., A. Hochhauser, D. F. Evans, and E. L. Cussler,^
"Concentrating Solutes with Membranes Containing Carriers,"
Nature, Vol. 250, August 9, 1974.
61
-------
Singer, P. C. and W. B. Zilli, Water Research, 9, 127-134, 1975,
Vesilind, P. A., Treatment and Disposal of Wastewater Sludge,
Ann Arbor Science Publications, Inc., Ann Arbor, Mich.,
1974.
Wang, L. K-P, D. W. Goupil, and M. S. Wang, Purdue University
Engineering Extension Series, Vol. 141, Part 1, 569-578,
1972.
62
-------
Multiply
By
To Obtain
Barrels (bbls.) 158.98
Feet (ft.) .3048
Feet per hour (ft./hr.) 0.508
Gallons (gal.) 3.785
Gallons per day (gpd) 3.785
Gallons per minute (gpm) 3.785
Gallons per minute per 40.74
square foot (gpm/ft.2)
u> Inches (in.) 2.54
Pounds (Ib.) 0.4536
Pounds per cubic foot (lb./ft.3) 16.02
Pounds per day (Ib./day) 0.4536
Pounds per hour (Ib./hr.) 0.4536
Pounds per square foot 4.882
per day (lb./ft.2)
Pounds force per square inch 0.07031
(psia)
Standard cubic feet (scf) 26.79
Liters (1)
Meters (m)
Centimeters per minute (cm/min.)
Liters (1)
Liters per day (I/day)
Liters per minute (1/min.)
Liters per minute per square
meter (1/min./m2)
Centimeters (cm)
Kilograms (kg)
Kilograms per cubic meter (kg/m3)
Kilograms per day (kg/day)
Kilograms per hour (kg/hr.)
Kilograms per square meter
per day (kg/m /day)
Kilograms force per square
centimeter (kg/cm2)
Liters at STP (1)
o
O
en
H
O
M
>
-------
Appendix B
ANALYTICAL METHODS
Standard analytical procedures were used for the routine analysis
of pH, total alkalinity, acidity, total dissolved solids (TDS),
suspended solids, chloride ion, organic nitrogen (Kjeldahl
nitrogen), ammonia nitrogen, oil and grease and APHA color.
Sulfate ion in high concentration was analyzed using the benzidine-
dihydrochloride method. In low concentrations, sulfate ion was
determined by using an ion chromatograph. Trace metal ions were
determined, using emission spectroscopy.
In the case of Stream 1, a method was required for the analysis
of sodium hydroxide exclusive of the amines present. A non-
aqueous titration method was developed for this analysis.
The analysis of the organic constituents of the petrochemical
waste waters was more difficult to perform and to interpret.
The characterization of the organic content of the waste waters
required the use of gas chromatographic methods to identify and
quantify the organic compounds present. A gas chromatographic
method was developed for the analysis of the organics in Stream 1
and Stream 2. Conditions of GC analysis of Stream 2 are given in
Table B-l.
Other methods were used to monitor the organic content of the
waste waters. Total organic carbon (TOC), inorganic carbon (1C),
and total carbon (TC) were determined using a Beckman Model 915
carbon analyzer. The method entails the injection of a micro
sample into a catalytic combustion tube at 950ฐC. The carbon-
aqueous material is oxidized to carbon dioxide in a carrier stream
of air. The amount of CO2 produced is directly proportional to
the amount of carbonaceous material in the injected sample and is
measured by a sensitized infrared analyzer. This determines the
total carbon. A second injection of the sample is made into a
low temperature oven tube containing phosphoric acid and the in-
organic carbon is released and purged by an air stream to the
infrared detector. This determines the inorganic carbon. The
difference between the two values is the total organic carbon.
Total oxygen demand (TOD) was also used to determine the organic
content of the waste waters. An Ionics Model 225 Total Oxygen
Demand analyzer was used. The determination is made by injecting
a micro sample of the waste water in a combustion tube containing
a platinum catalyst at 950ฐC. The catalyst tube is continually
64
-------
purged with a flow of nitrogen contaminated with a low concentra-
tion of oxygen. The oxidation of the carbon in the injected
sample causes a decrease in the oxygen level in the nitrogen
stream. This will register as a change in electrical output from
a silver-lead fuel through which the nitrogen stream flows. This
response is proportional to amount of oxidizable organic carbon
present in the sample.
65
-------
Table B-l. GAS CHROMATOGRAPHIC ANALYSIS CONDITIONS -
STREAM 2
Gas Chromatograph
Detector
Injector Temperature
Detector Temperature
Columns
Column Packing
Oven Temperature
Carrier Gas
Carrier Gas Flow Rate
Air Flow Rate
Hydrogen Gas Flow Rate
Sample Injection
Calculation
Retention Times
Hewlitt-Packard 5711A
Dual FID
110ฐC
300ฐC
12 ft. x 1/8, SS
10% Carbowax 20M on Chromosorb
W-HP 80-100 mesh ,
Isothermal 110ฐC
Helium
30 cc/min. at 60 psi
240 cc/min. at 24 psi
30 cc/min. at 15 psi
3 microliters of 1:1 CS2
extract of the sample
Integration and calculation
performed by HP 3380A
Integrator-Recorder
Benzene - 1.75 min.
Ethylbenzene - 5.05 min.
66
-------
Appendix C
AMMONIA REMOVAL
A. Literature Review
Several processes are presently used for ammonia removal from
waste waters. The concentration of ammonia is an important factor
in determining which process to use.
For ammonia concentrations of the order of several percent, stream
stripping in a column desorber with countercurrent flow is gen-
erally used. A wet ammonia overhead is obtained which can be re-
cycled directly or condensed to produce an aqueous solution.
Effluent waste water can be expected to contain about 1000 ppm
ammonia. Secondary stripping is used to reduce the effluent
level to near 50 ppm ammonia. The secondary stripper overhead
can be used as a steam source for the primary desorber. This
degree of ammonia removal may be sufficient in some cases, but
frequently it is not.
To remove ammonia from waste waters containing concentrations in
the 100 ppm or less range, four processes have been used. These
are air stripping, nitrification-denitrification, selective ion
exchange, and breakpoint chlorination.
Air stripping is generally accomplished in a countercurrent or
crosscurrent flow tower very similar to a water cooling tower.
Large fans draw air through waste water that trickles through
slats of wood or plastic, desorbing the ammonia. The pH of the
waste water is adjusted to a value near eleven, usually with
lime. This converts all ammonium ions to dissolved ammonia. The
air requirement is of the order of 300 cu.ft. per gallon of liquid.
The air stripping process is simple and reliable, and removals
range from 60 to 95 percent. The removal efficiency at low tem-
peratures is poor because ammonia solubility is inversely related
to the temperature. If lime is used to raise the pH, scaling
may be a problem. The discharge of ammonia into the atmosphere
can be prevented, if necessary, by scrubbing the ammonia-rich gas.
Nitrification-denitrification is accomplished by biological ox-
idation of the ammonia to nitrite or nitrate, followed by bio-
logical reduction to nitrogen gas. This process can be carried
out in various biological reactor systems, and as in all micro-
biological reactors, the major operational difficulty encountered
is insolubility. The nitrification step is aerobic, while the
67
-------
denitrification step is anaerobic. A substrate, such as methanol,
must be added to the waste for denitrification to occur. Ammonia
removal efficiencies range from 80 to 98 percent.
In the breakpoint chlorination process, the ammonia is oxidized
to various chloramines, and then to nitrogen gas. About 10 parts
of chlorine are required for every part of ammonia-nitrogen that
is reacted. Dechlorination may follow chlorination to remove
residual chlorine, or carbon adsorption to remove unoxidize chlor-
amines. For high concentrations of ammonia, breakpoint chlorina-
tion is not economical because of chlorine costs. However,
removal efficiencies of 90 to 100 percent have been reported,
and this process is often used following one of the previously
mentioned processes to reduce the residual ammonia level to near
zero.
B. Ammonia Removal Tests
1. Liquid membrane process
A process by which both the ammonia and the amines could be re-
moved and recovered simultaneously would be of great value in
pretreating this waste water. One process that offers this
possibility is the liquid surfactant membrane process described
by Li and Shrier (1972).
A schematic diagram of the conceptual Liquid Membrane Water
Treatment Process is shown in Figure C-l.
Liquid surfactant membranes are formed by first making an emulsion
of two immiscible phases such as a water and an oil. A surfactant
is added to stabilize the emulsion. The emulsion is then dis-
persed into a third phase. The liquid membrane phase refers to
the phase between the encapsulated phase in the emulsion and the
third phase. The encapsulated phase and the third phase are
usually miscible but are immiscible with the membrane phase. The
liquid membranes can be modified for specific applications and
the large surface area of the membrane allows rapid permeation
and equilibration during mixing. Facilitated transport can be
used to enhance this mass transfer. This involves encapsulation
of a reagent within the membrane that reacts with the permeating
specie and forms a specie that will not permeate. After suf-
ficient contact time between the emulsion and the third phase,
mixing is stopped and the phases are allowed to separate. The
emulsion can then be decanted off the top and de-emulsified to
release the permeated specie.
Li, N. N. and A. L. Shrier. "Liquid Membrane Water Treating",
Recent Developments in Separation Science, Vol. 1, CRC Press,1972.
Cahn, R. P. and N. N. Li. "Separation of Phenol from Waste Water
by the Liquid Membrane Technique," Separation Science, 9(6),
505-519, 1974.
68
-------
Contaminated
Water Feed
1200 rpm
Reagent
Makeup
Emulsif ier
Chemicals
Makeup
100 - IEMULSIFICAT ION]
200 rpm
s*J LM Emulsion,
Fresh
Emulsion
Recycle
Emulsion
Mixer
Settler
Recovered Liquid
Membrane Components
(Solvent, Surfactants,
etc.)
I CONTACTING | (may be multistage)
Demulsif ier
SPENT
EMULSION
TREATMENT
Spent Reagent
to Recovery
'or Disposal
*Effluent Water
to Further
Discharge
Figure C-l. SCHEMATIC DIAGRAM OF CONCEPTUAL LMWT PROCESS
-------
Liquid membranes have been demonstrated (Li and Shrier, 1972;
Cahn and Li, 1974) to:
1. Remove weak acids such as phenol, H2S, HCN, and
acetic acid from water.
2. Remove weak bases such as ammonia and amines from
water.
3. Purify hydrocarbons and separate toluene from
heptane and benzene from hexane.
4. Remove suspended solids from waste water.
5. Remove selectively chromium, cupric, mercuric,
silver, sulfide, nitrate, and phosphate ions from
water (Schiffer, et al, 1974; Hochhauser, 1974).
A synthetic waste water containing 160 mg/1 ammonia and 1000 mg/1
ethylene diamine in pH 12 caustic was treated with liquid surfact-
ant membranes. The membrane was produced by adding at 10 ml/min,
approximately 80 mis of 0.1 N hydrochloric acid to approximately
160 mis of S-100-N oil containing 2 percent by weight SPANฎ 80.
The mixing was done at 1300 rpm using a Fisher Stedi-Speed Model
12 stirrer. The mixing continued for 10 minutes after the last
of the acid was added. A thick milky white emulsion was formed.
The resulting 250 mis of emulsion was mixed with 250 mis of
synthetic waste water at 200 rpm. Samples were taken of the
aqueous phase at timed intervals. These samples were analyzed
for ammonia and ethylene diamine.
Table C-l summarizes the experimental conditions and results.
Figure C-2 presents a plot of the Ct/Co versus the time of contact
with the liquid membrane.
The results indicated that the ammonia was removed within 5
minutes and the maximum ethylene diamine removal occurred in 15
minutes. The ethylene diamine removal stopped short of complete
removal because there was not enough acid to react with the
remaining ethylene diamine. Membrane breakage and subsequent
neutralization of the acid may account for the fact that only 94
percent of the acid was reacted when the permeation stopped. The
concentration factor for ammonia was approximately 3 because the
ammonia that was contained in the 250 mis was transferred in the
80 mis of acid within the membrane.
Schiffer, D. K., A. Hochhauser, E. F. Evans, and E. L. Cussler,
"Concentrating Solutes with Membranes Containing Carriers,"
Nature, Vol. 250, August 9, 1974.
Hochhauser, A. M. "Concentrating Chromium with Liquid Surfactant
Membranes," Ph.D. dissertation, University Microfilms No. 74-20,
365, Ann Arbor, Michigan, 1974.
70
-------
Table C-l. LIQUID MEMBRANE TREATMENT OF SYNTHETIC
STREAM 1 WASTE WATER
Volume of liquid membrane taken
Volume of waste water taken
Total time of experiment
Initial ammonia concentration
Final ammonia concentration
Ammonia removed
Initial ethylene diamine
concentration
Final ethylene diamine
concentration
Ethylene diamine removed
Ammonia removed
Ethylene diamine removed
Total removed
Total meq of HCl available
HC1 usage
Concentration factor-ammonia
250 mis
250 mis
60 minutes
160 mg/1
0 mg/1
100%
1000 mg/1
380 mg/1
62%
2.35 meq
5.17 meq
7.52
8.0
94%
3
71
-------
[C0 =160 mg/1 NH3 + 1000 mg/1 aminej
10
20 30 40
Time, minutes
60
Figure C-2.SYNTHETIC STREAM 1 - WASTE WATER
LIQUID MEMBRANE TREATMENT
72
-------
Although the initial experiment showed some promise for this
technique, attempts to increase the concentration factor by
encapsulating a higher concentration of hydrochloric acid in the
membrane were unsuccessful. The liquid membrane formed was too
unstable. Experiments with waste water which contained a
higher sodium chloride level than the synthetic also failed
because of membrane instability. No experiments were run to
determine the ease with which the exhaust liquid membrane could
be de-emulsified to recover the ammonia and amine hydrochlorides.
Further extensive work will be required to develop a liquid
surfactant membrane which remains stable in the presence of
higher HC1 concentrations and higher brine waste waters.
2. Ion exchange
One other method of ammonia removal from waste water was tried.
This was the use of clinoptilolite as an ion exchanger to remove
ammonium ions from the water. This process has been described
variously in the literature in conjunction with removal of ammonia
from municipal waters (Mercer, et al, 1970; McLaren and Farquhar,
1973; Battelle-Northwest, 1971). A supply of clinoptilolite was
obtained and prepared (McLaren and Fraquhar, 1973). A small
column was filled with 20 grams of resin. A flow rate of 1 gpm/
sq.ft. was set. The feed solution neutralized Stream 1 waste
water. Figure C-3 shows the results of this experiment. The
exchange capacity was found to be 0.28 meq. of ammonia-nitrogen/
gm. of resin, much less than the capacity (1.6-1.8 meq./g.) given
by the supplier (McLaren and Farquhar, 1973). A value of 0.95
meq./g. was obtained for a water containing 70 mg/1. ammonia-
nitrogen.
Apparently at the higher ion concentration of the waste water,
the cations compete with the ammonia for exchange sites and the
capacity of the resin for the ammonia ion is much too low to be
used to remove ammonia from Stream 1 waste water.
Mercer, B. W. et al. "Ammonia Removal from Secondary Effluents
by Selective Ion Exchange," Journal WPCF, 42(2) Part 2, 1970.
McLaren, J. R. and G. J. Farquhar. "Factors Affecting Ammonia
Removal by Clinoptilolite," Journal of Environmental Engineering.
429, August, 1973.
Battelle-Northwest, "Wastewater Ammonia Removal by Ion Exchange,"
EPA-Water Pollution Control Series No. 17010 ECZ 02/71, 1971.
73
-------
200
tn
e
100
C0 = 218 mg/1 NH3-Nitrogen
I
I
I
I
I
I
I
I
I
I
100 200 300 400 500 600 700 800
5 10 15 20 throughput 40
900 1000 1100 1200 1300 1400 ml.
50 Bed volume
Figure C-3. EXCHANGE OF NHU + ON CLINOPTILOLITE FROM
STREAM 1 WASTE WATER
-------
Appendix D
TOTAL RECYCLE SYSTEM DESIGN AND COST ESTIMATES FOR STREAM 1
The process design of the unit operations required for the total
recycle of Stream 1 are based on a flow rate of 1 MGD wastewater.
A cost estimate of the total system is made based on 1975 costs.
A. Pretreatment Design
1. Carbon adsorption
The bed depth-service time, for 95 percent TOC removal is plotted
in Figure D-l. One column test was run at the lower rate of 1
gpm/ft2 and the rest were made at 2 gpm/ft2. The agreement
between the values obtained from the actual 2 gpm/ft2 run and
those calculated from the 1 gpm/ft2 converted to 2 gpm/ft2 was
excellent. From the results of the electrodialysis-reverse
osmosis tests, it was evident that the TOC removal must be
maximized. This is why 95 percent removal was selected. The
design bed versus service time relationship for 95 percent
removal was:
t = 0.38(x) - 1.25
where:
t = service time, hours
x = bed depth, feet
The carbon treatment unit is designed for a linear flow rate of
4 gpm/ft2, to handle 1 MGD of wastewater, of 1650 mg/1 feed TOC,
producing a TOC concentration of 80 mg/1. The activated carbon
is Westvaco WV-G, 12 x 40 mesh of 25 Ibs/cu.ft. density.
The cross-sectional area requirement is:
500,000 gpd/(4 gpm/ft2)(1440 min/day) = 87 ft2
(The area for a 1,000,000 gpd unit was too great, so
the process unit will be divided into two parallel
trains. Each will treat 500,000 gpd.)
The carbon bed volume will be:
87 ft2 x 20 ft. (bed depth) = 1740 ft
The adsorber volume will be (50% higher for backwash)
1740 ft3 x 1.5 = 2610 ft3
The adsorber dimensions:
30 ft x 10.5 ft I.D.
75
-------
14
12
10
en
S-)
2
o
0)
0)
o
-H
-------
The bed dimensions will be:
20 ft x 10.5 ft I.D.
The weight of the carbon per bed will be:
1740 ft3 x 25 Ibs/ft3 = 43,500 Ibs
The bed service time will be:
t = 0.19(20) - 1.25 = 2.5 hours
Three columns in series will operate for approximately 8 hours
or one shift. Each one will need to be regenerated once per
shift. A fourth column will be needed for the regeneration. To
handle the 1 MGD of Stream 1, two trains of four columns will be
needed. Three columns will be in operation at one time while
one column in each train is being regenerated.
The acid requirement for the regeneration of the carbon was
determined to be 1.8 bed volumes of acid per regeneration.
However, 0.3 bed volumes are recycled back to the acid tank so
1.5 bed volumes is actually used. Approximately 10 regenerations
will be required per day per train or 20 all together. Therefore,
30 bed volumes of 30 x 13,000 gal. will be required per day.
This is 390,000 gallons of 2 N acid or 65,000 GPD of concen-
trated acid (12 N).
Figure D-2 shows a flow diagram and material balance for one
train of the process.
The capital cost for the carbon treatment includes adsorbers,
pumps, carbon, tanks and associated equipment. These are shown
in Table D-l. The operating cost includes utilities, amor-
tization, labor, carbon replacement, and acid costs. These are
shown in Table D-2.
2. Neutralization
The acid requirement for the neutralization of Stream 1 was
determined to be 22 gal. of concentrated HC1 per 1000 gals, of
Stream 1. After carbon treatment, the stream volume was 1,180,000
gal. After neutralization, the stream rate will be 1,206,000.
It will require 26,000 gal. of concentrated acid per day, or 9.5
Mgal/yr. The capital and operating costs for neutralization are
given in Table D-3.
3. Silica removal
The design and costs are presented for silica removal. A 1.2
MGD stream after neutralization must be treated with an alumina
column. Table D-4 is the design bases. Figure D-3 gives the
process design and material balance. The process consists of
two trains of two columns each. Each column is 16 ft. long x
11.5 ft. diameter. The bed volume is 1675 ft and each contains
92,000 Ibs. of F-l alumina. Before regeneration, 190 bed
volumes are treated with 1.5 bed volumes of caustic. Table D-5
gives the cost estimate for this process.
77
-------
0.5 mgd
to r~L
n 1 ฎ
u x 1
Feed
Tank
ซ
" -*"*.
Ld
Mi v
(?) Tank
oo _______
NaCl 150 1,550 1,550
1
'
l_
n
^^^^H
0
ฉ
1
L
muM
ฉ
\
\
i
(D
^v
ฉ ฉ ฉ
1,400
HC1 -- -- 4,900
NaOH 1,500 1,500 1,500
TOC 300 330 15
700 4,200
500
1
280
H20 171,800 201,470 201,470 81,300
Organics
30
5
35,450 29,670 12,850 11,400 57,300
410
Total 173,750 205,350 205,035 86,200
Sp. Gr 1.01 1.01 1.01 1.03
Flow, gpd 500,000 590,000 590,000 234,000
j __
36,140 31,600 13,550 15,600 57,300
1.03
1.03
1.03 1.19 1.0
104,000 91,000 39,000 32,700 465,000
Figure D-2. TOTAL RECYCLE SYSTEM STREAM 1 - CARBON TREATMENT
PROCESS DESIGN AND MATERIAL BALANCE
-------
B. Electrodialysis-Reverse Osmosis Design
The basis for the design to handle the pretreated Stream 1 waste
is given in Table D-6. The material balance is given with the
flow diagram presented in Figure D-4.
For the reverse osmosis unit, the capital cost is calculated as
0.65 dollars per gallon per day permeate and the operating cost
as 0.60 dollars per 1000 gallons of permeate. For the electro-
dialysis unit, 2 presses 1800 cell pairs each are required.
The cost per press of $500,000 times a factor of 2.5 gives the
total plant cost.
A summary of the capital and operating costs of the reverse
osmosis-electrodialysis hybrid is given in Table D-7.
79
-------
Table D-l. 1-MGD STREAM 1 - ACTIVATED CARBON TREATMENT
ESTIMATE OF DIRECT CAPITAL COST
Installed
Item Cost
Adsorption Columns (8) at $200,000 each
30' x 10.51 dia. - Monel-Vertical Vessel $1,600,000
Pumps (8) 15,000
Pumps - Acid Service (2), Monel 20,000
Carbon, Initial Charge - Westvaco WV-G,
12 x 40 Mesh, 348,000 Ibs. at $.50 174,000
Feed Equilization and Storage Tank
1/2 Day Volume (10,100 bbl.) 78,000
Acid Storage Tank (2,100 bbl.)
8-Hour Capacity Rubber Lined Carbon Steel 54,000
General Services (10%) 190,000
Direct Capital $2,131,000
Allocated Capital - Electric Power 50,000
Factory Expense (7% of Direct Capital) 149,000
FIXED CAPITAL $2,330,000
80
-------
Table D-2. 1-MGD STREAM 1 - ACTIVATED CARBON TREATMENT -
ESTIMATE OF OPERATING COST
Item
Raw Materials
HC1, 38%
Carbon Replacement
Operating Labor
Maintenance
Power
River Water
Factory Expense
Taxes and Insurance
Depreciation
Quantity
9 x 107 Ibs.
34,000 Ibs.
Cost per
Unit
$0.02
0.50
4 Man-yrs.
6% of Process
Equipment Capital
60 M Gal.
0.025
2.6% of Direct
Capital
1.1% of Direct
Capital
10% of Direct
Capital
Cost per
Year
$1,800,000
17,000
100,000
128,000
20,000
2,000
55,000
23,000
213,000
$2,358,000
TOC Removed per year =
Organics Recycled per year =
Cost per Ib. Organics Recycled =
Value of Organics at 50* per lb.=
2.45 x 106 Ibs.
6.0 x 106 Ibs.
$.39/lb.
$3,000,000 $/yr.
81
-------
Table D-3. 1-MGD STREAM 1 - NEUTRALIZATION
ESTIMATE OF CAPITAL AND OPERATING COSTS
Item Cost
Capital Cost;
Mixing Tank - Rubber Lined
8-Hour Capacity, 400,000 gal. $ 54,000
Pump - Acid Service, Monel 10,000
Pump 2,000
General Service (10%) 6,000
Direct Capital $ 72,000
Allocated Capital, power 10,000
Factory Expense (7%) 5,000
FIXED CAPITAL $ 87,000
Operating Cost;
Cost $/yr.
Raw Materials, HC1, 38%
9.4 x 107 Ibs. at $0.02 $1,880,000
Maintenance (6%) 4,000
Power 5,000
Factory Expense (2.6%) 2,000
Taxes and Insurance (1.1%) 1,000
Depreciation (10%/yr.) 7,000
$1,900,000 $/yr,
82
-------
Table D-4. SILICA REMOVAL - STREAM 1
Design Basis:
Linear Flow Rate
Design Flow
Design Silica
Concentration
Design Product
Concentration
Capacity
Bed Depth
Alumina
Density
- 4 gpm/ft.2
- 50 mg/1
- <10 mg/1
30 minutes
20 mg Silica/g Alumina
- 16 ft.
Alcon F-l
- 55 lbs./cu. ft.
83
-------
Feed (k Total Flow)
(1)
In Sodium Hydroxide
1
2
^ฉ
_ Trpat^d S-i-r^am 1
ฉ
Spent Caustic
NaOH
Silica
H20
Total
Flow
Units
Ibs/hr
gpd
10.5
208,490
208,500
600,000
70
2.1
208,490 1639
208,492 1700
600,000 5000
70
8.4
1621.6
1700
5000
Figure D-3. TOTAL RECYCLE SYSTEM - STREAM 1
SILICA REMOVAL, DESIGN BASIS AND
MATERIAL BALANCE
84
-------
Table D-5. ACTIVATED ALUMINA TREATMENT OF STREAM 1 -
ESTIMATE OF CAPITAL AND OPERATING COSTS
Item Cost
Capital Cost:
Four Adsorber Columns at $36,000 each
(16' x 115' dia. - Carbon Steel) $144,000
Caustic Mix Tank
1-Day Capacity - Carbon Steel 9,000
Two Pumps 4,000
Alumina, 370,000 Ibs. at $0.15/lb. 56,000
General Services (10%) 22,000
Direct Capital $235,000
Allocated Capital 10,000
Factory Expense (7%) 16,000
$261,000
Operating Cost; $/yr.
Raw Materials
100% Caustic, 600,000 Ibs. $ 30,000
Water, 1,825,000 gallons 40ฐ
Maintenance (6% of Capital) 16,000
Power 5'000
Factory Expense (2.6%) 7,000
Taxes and Insurance (1.1%) 3,000
Depreciation (10%/yr.) 26'000
$ 87,400
85
-------
Table D-6. 1-MGD STREAM 1 - ELECTRODIALYSIS-REVERSE
OSMOSIS DESIGN
Basis:
Design NaCl Feed Concentration
Design Brine Product
Design R.O. Product
Feed Rate
Volts/cell pair
Current Density
R.O. Product Recovery
NaCl Rejection
Number of SS-0 Press
Cell Pairs
Operation
- 14,000 mg/1 (0.24 N)
- >140,000 mg/1
Maximum 2.4 0 N
- <500 mg/1 (0.009 N)
- 1.2 mgd
- 0.74
1.6 amp/dm2
- 48%
- 95%
- 2
- 3131
- 330 day/yr.
86
-------
Brine
Recycle
Neutralized
Feed
Reject
Electro-dialysis
Dilution
Recycle
CD
TR
Reverse
Osmosis
AFeed
Permeate
Brine
Product
'Water
Reject
Reverse Osmosis
Ib/hr (& (& (& (V 15; (6)
NaCl 5,850 8,720 5,700 3,020 150 2,870
H20 418,000 712,000 34,000 678,000 384,000 294,000
Total 423,850 720,720 39,700 681,020 384,150 296,870
Figure Q-4. ELECTRODIALYSIS-REVERSE OSMOSIS OF
PRETREATED STREAM-1, FLOW DIAGRAM
AND MATERIAL BALANCE
87
-------
Table D-7. COST ESTIMATE SUMMARY - ELECTRODIALYSIS-
REVERSE OSMOSIS TREATMENT OF STREAM 1
Reverse Osmosis;
Capital $ 615,550
Operating Cost 187,500 $/yr.
Electrodialysis;
Capital $2,500,000
Operating Cost
Power 133,530
Membrane Replacement 87,000
Total Labor 38,250
Miscellaneous 50,000
Depreciation 250,000
Total $ 458,780 $/yr.
ED-RO;
Total Capital $3,115,550
Total Operating Cost $ 646,280 $/yr.
88
-------
Appendix E
TOTAL RECYCLE SYSTEM DESIGN AND COST ESTIMATES FOR STREAM 2
A total recycle system is designed for the treatment of 1 MGD of
Stream 2 waste water. The pretreatment steps before the electro-
dialysis-reverse osmosis hybrid are the neutralization, solids
removal7 and carbon adsorption. A cost estimate of each step is
made based on 1975 costs.
A. Pretreatment Design Bases
1. Neutralization and solids removal
A flow diagram and a material balance is given in Figure E-l.
The feed contains 680 mg/1 of Al ion that results in 150 mg/1
of suspended solids, A1(OH)3 after neutralization. The primary
settling tank underflow concentration of 500 mg/1 at a flow of 0.3
MGD requires a surface area of 5600 ft . The sludge is thickened
in a centrifuge at 1100 G's acceleration, to a 2 percent compacted
sludge. The volume of the sludge is reduced to 75,000 GPD.
A capital and operating cost of this pretreatment step is given
in Table E-l.
2. Carbon adsorption
The design basis and parameters of the carbon adsorption system
for Stream 2 are given in Table E-2. The flow diagram and mate-
rial balance are shown in Figure E-2. A summary of the capital
and operating costs is given in Table E-3.
B. Electrodialysis-Reverse Osmosis Design
The design basis of the ED-RO hybrid for recycle of fresh water
and concentrated brine from the pretreated Stream 2, is given in
Table E-4. A flow diagram and material balance is shown in
Figure E-3.
For the reverse osmosis unit, the capital is calcultated as 0.65
dollars per day permeate and the operating cost as 0.6 dollars
per 1000 gallons of product water. For the electrodialysis unit,
6 presses, 1800 cell pairs each, are required. The cost per press
of $500,000 times a factor of 2.5 gives the estimated capital cost.
Membrane replacement is based on 7 years lifetime. A summary of
capital and operating costs of the reverse osmosis-electrodialysis
hybrid for Stream 2 recycle is given in Table E-5.
89
-------
Waste Water
/ C3J
vo
o
Al
NaCl
H2O
TOC
HC1
Total
Total
NaOH
(D ,
^-^
ฉ
V Primary /
\Settler/
Clarified
Waste
HCl \ /
ฉ
Solids Disposal /g\ X*^"\ /g\
/->y Ponc^ ^ ^ ' 1 1 v^
Units Ci)
lb./hr. 240
lb./hr. 14,564
lb./hr. 332,494
lb./hr. 30
lb./hr.
lb./hr. 347,500
M gpd 1.0
Sp Gr 1.02
lb./hr. 1,720
V 1
\ y Centrifuge
ฉ ฉ ฉ
0 240
10,394 4,454
2,256 234,325 100,425
21 9
1,324
3,580 244,740 105,1246
0.0103 0.7072 0.3031
1.19 1.02
1.0103
ฉ ฉ
0 240
3,340 1,114
75,313 25,112
8 1
78,844 26,282
0.227 0.076
1.02
ฉ
0
13,734
309,638
29
323,584
0.934
1.02
Figure E-l. NEUTRALIZATION AND SOLIDS REMOVAL - STREAM 2
Flow Diagram and Material Balance
-------
Table E-l. NEUTRALIZATION AND SOLIDS REMOVAL - CAPITAL
AND OPERATING COST ESTIMATES - STREAM 2
Capital Cost;
Mixing Tank - rubber lined, 4 x 105 gallons $ 54,000
Pumps, Monel 16,000
Gravity Thickener 75,000
Centrifuges 50,000
G&A (10%) 20,000
Direct Capital $215,000
Allocated Capital, power 20,000
Factory Expense (7%) 15,000
FIXED CAPITAL $250,000
Operating Cost; $/yr.
Raw Materials
HCl 37%, 3.4 x 106 Ib./yr. $ 68,000
Maintenance (6%) 15,000
Power 10,000
Factory Expense (2.6%) 6,500
Taxes and Insurance (1.1%) 2,700
Depreciation (10%) 21,500
$123,700 $/yr,
91
-------
Table E-2. CARBON ADSORPTION OF STREAM 2 - DESIGN BASIS
Feed Concentration TOC
Effluent TOC
Flow Rate
Columns - 4, 2 trains
Bed Volume
Weight Carbon (Witco 517)
Service Time
Capacity
Regeneration Capacity
- 90 mg/1
- 18 mg/1
4.0 gpm/ft.2
- 20' x 18' diameter
each
- 2,430 cu. ft.
- 60,750 Ib./bed
- 713 hours
- 13.5 Ib. TOC/lb. carbon
8,200 Ib. carbon/day
92
-------
Two Trains
* t
Loading
Cycle
A
B
Regeneration
Cycle
1
t Q
Units 1 2
TOG lb./nr. 74.5 3
NaCl lb./hr. 6,867 6,867
Water lb./hr. 754,819 154,819
Total lb./hr. 161,700 161,700
Figure E-2. FLOW DIAGRAM AND MATERIAL BALANCE FOR
CARBON ADSORPTION TREATMENT - STREAM 2
93
-------
Table E-3. CARBON ADSORPTION - CAPITAL AND OPERATING
COST ESTIMATES - STREAM 2
Capital Cost;
Adsorption Columns
Four, 20' x 14' diameter $ 224,000
Initial Carbon
244,000 Ibs. at 50<=/lb. 122,000
Thermal Regeneration Unit
8,200 Ib./day capacity 492,000
General Services (10%) 84,000
Direct Capital $ 922,000
Allocated Capital, power and steam 20,000
Factory Expense (7%) 65,000
FIXED CAPITAL $1,017,000
Operating Cost: ... ,
_ฃ 2 $/yr.
Utilities $ 40,000
Labor and O.K. 70,000
Carbon Make-up (7%) 100,000
Maintenance (6%) 60,000
Factory Expense (2.6%) 26,000
Taxes and Insurance (1.1%) 11,000
Depreciation (10%) 100,000
$ 407,000
94
-------
Table E-4. ELECTRODIALYSIS - REVERSE OSMOSIS
TREATMENT - STREAM 2
Design Basis;
Feed NaCl Concentration - 4.24%
Feed Normality - 0.74N
Design Brine Concentration - 2.39N
Design Product Quality - <500 mg/1
Feed Rate - 0.934 mgd
E.D. Current Density - 1.95 amp/dm2
E.D. Volts/cell pair - 0.55
R.O. Product Recovery - 55%
R.O. NaCl Rejection - 97%
No. of SS-0 Presses - 6
No. of Cell Pairs - 10,800
95
-------
Brine
Recycle
Neutralized
Feed
Reject
ฃ3
Brine
Dilution
Recycle
I'
1C
I Feed
H Reverse
Dsmosis
Product
'Water
Permeate
Reject
Reverse Osmosis
Units
NaCl lb./hz: 13,734 15,520 13,730 1,790 30 1,700
H20 Ib./hr. 309,638 474,480 94,270 380,210 215,348 164,922
Total Ib./hc 323,378 490,000 108,000 382,000 215,378 166,622
Flow mgd 0.934 1.410 0.31 1.10 0.62 0.480
Figure E-3. ELECTRODIALYSIS-REVERSE OSMOSIS TREATMENT -
STREAM 2
Flow Diagram and Material Balance
96
-------
Table E-5. COST ESTIMATE SUMMARY - ELECTRODIALYSIS
REVERSE OSMOSIS TREATMENT OF STREAM 2
Reverse Osmosis:
Capital $ 403,000
Operating Cost 122,760
Electrodialysis:
Capital $7,500,000
Operating Cost
Power 377,800
Membrane Replacement 294,000
Total Labor 68,250
Miscellaneous 150,000
Depreciation 750,000
Total $1,640,050 $/yr.
ED-RO;
Total Capital $7,903,000
Total Operating Cost $1,763,000 $/yr.
97
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA-600/2-79-021
3. RECIPIENT'S ACCESSION-NO,
4. TITLE AND SUBTITLE
TOTAL RECYCLE SYSTEMS FOR PETROCHEMICAL WASTE
BRINES CONTAINING REFRACTORY CONTAMINANTS
5. REPORT DATE
January 1979 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
M. A. Zeitoun
C. A. Roorda
8. PERFORMING ORGANIZATION REPORT NO.
G. R. Powers
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Dow Chemical Company
Freeport, Texas 77541
10. PROGRAM ELEMENT NO.
1BB61Q
11. CONTRACT/GRANT NO.
S 803085-01-0
12. SPONSORING AGENCY NAME AND ADDRESS
Robert S. Kerr Environmental Research
Office of Research and Development
U.S. Environmental Protection Agency
Ada, Oklahoma 74820
Lab. - Ada, OK
13. TYPE OF REPORT AND PERIOD COVERED
FTNAT.
T4. SPONSORING AGENCY CODE
EPA/600/15
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Petrochemical wastewaters containing relatively high concentrations of
salt and refractory organics were selected to study their feasibility for
total recycle. A combination of reverse osmosis and electrodialysis was
operated as a hybrid system using the pretreated wastes to produce reusable
water and a concentrated brine.
The combined electrodialysis-reverse osmosis system is not considered
economically feasible when applied to industrial wastewaters containing
relatively high concentrations of salt.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. cos AT I Field/Group
Activated Carbon Treatment
Electrodialysis
Circulation
Brines
Reverse Osmosis
Reuse
Petrochemical Industry
68D
8. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport)
21. NO. OF PAGES
108
(This page)
22. PRICE
Unclassified
EPA Form 2220-1 (9-73)
98
U. S. GOVERNMENT PRINTING OFFICE: 1979 657-060/1591
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