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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, US 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.
2.
3.
4.
5.
6
7
8.
9
Environmental Health Effects Research
Environmental Protection Technology
Ecological Research
Environmental Monitoring
Socioeconomic Environmental Studies
SCientific and Technical Assessment Reports (STAR)
Interagency Energy-Environment Research and Development
"Special" Reports
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 Technicallnforma-
tion Service, Springfield, Virginia 2216-1.
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EPA-600j2-78-048
March 1978
TREATMENT AND RECOVERY OF FLUORIDE
AND NITRATE INDUSTRIAL WASTES
PHASE II
by
Christian J. Staebler, Jr.
Grumman Aerospace Corporation
Bethpage, New York 11714
Project No. S800680
Project Officer
Hugh B. Durham
Industrial Pollution Control Division
Industrial Environmental Research Laboratory
Cincinnati, Ohio 45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U. S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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ABSTRACT
Laboratory and pilot-scale techniques to treat selected aerospace- and metal-
working-industry chemical processing solutions and rinse waters containing fluo-
rides and nitrates were developed and successfully demonstrated. Lime-treatment
parameters such as temperature, retention time, pH, and slurry concentration were
optimized for various fluoride and nitrate influent levels in chemical processing
solutions to minimize the fluoride and nitrate effluent levels. Ion-exchange tech-
niques were developed thaJreduce the fluoride and nitrate concentrations of rinse
waters to levels of 3 and 10 ppm, respectively.
Pilot-scale centrifugal techniques to separate precipitated calcium fluoride
and metal hydroxide sludges were developed. The nitrate concentration of centri-
fuged effluents was reduced from 28,000 to less than 5 ppm in the optimized pilot-
scale system by passing these effluents through a thin-film, mechanically aided
evaporator. The fluoride concentration was reduced from 117,000 to less than 1
ppm in the pilot treatment system.
Chemical and mechanical property tests showed the potential feasibility of
using calcium fluoride sludge as a strength-maintaining additive for concrete.
Concentrated calcium nitrate recovered from the mechanically aided evaporator was
evaluated in conjunction with th~ Cornell University Extension Research Farm on
Long Island as a potential growth-enhancement material. Greenhouse tests indi-
cated that this material is a beneficial and practical plant fertilizer.
The economics and production scale-up plans for ion-exchange rinse water
treatment and process solution treatment are also presented.
The report was submitted in fulfillment of Project S800680 by Grumman Aero-
space Corporation under the (partial) sponsorship of the Office of Research and
Development, U. S. Environmental Protection Agency. This report covers a period
from August 31, 1973 to March 31, 1976, and work was completed as of June 30,
1976.
iv
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Foreword
Abstract.
Figures.
Tables
CONTENTS
. . . .
.....
. . . .
......
......
........
.....
......
......
. . . . . .
.....
.........
........
........
......
.......
Acknowledgments.
......
.....
........
1.
Introduction
.........
2.
Conclusions .
. . . .
.......
......
3.
Recommendations.
. . . .
......
. . . .
4.
Ion- Exchange Treatment of Rinse Waters for Fluoride and
Nitrate Removal. .
......
.....
.....
Approach.
. . . .
...........
Study areas
.....
.....
Background.
. . . .
Equipment and materials.
.......
.........
Determination of column operating parameters.
Breakthrough capacity. . . . . .
pH and heavy-metal cation control.
.....
Resin stability. . . . . . . . . .
.....
.....
.....
.....
. . . . .
.....
.......
......
......
......
. . . .
............
Production scale-up and economic considerations .
.....
5.
Removal and Re- Use of Fluorides and Nitrate From Lime-Treated
Effluents. .
. . . .
. . . .
......
Approach. . . . . . .
........
.........
v
. . . .
iii
iv
vii
ix
xi
1
2
4
6
6
6
6
7
7
7
21
24
24
30
30
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CONTENTS (cont.)
Study areas. .
. . . . . . . . . . . .
. . . .
. . . .
Design of prototype treatment system.
......
Lime treatment and fluoride removal by centrifugation. . .
Removal of nitrates from lime-treated effluents. .
. . . .
Use of evaporator sludge as nitrogen fertilizer.
. . . . .
Calcium fluoride sludge re-use
......
. . . .
Bibliography.
Appendices
. . . . . . . . . . . . . . . .
. . . . .
. . . . . . .
A.
Procedure for analysis of fluoride
...........
. . . .
B.
Procedure for analysis of nitrate in calcium nitrate. . .
. . . .
C.
Procedure for analysis of nitrate in water samples.
.......
D.
Test of two waste products of Grumman Aerospace Corporation as a
source of nitrogen fertilizer. . . . . . . . . . . . . . . . .
vi
30
30
33
38
50
53
59
61
62
63
65
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Number
16.
17.
18.
FIGURES
1.
Two-stage ion-exchange system for rinse water treatment. . . . .
2.
Ion-exchange breakthrough test No.1.
Ion-exchange breakthrough test No. 2~
......
.....
3.
.......
.......
4.
Ion-exchange breakthrough test No.4. .
.......
5.
Ion-exchange breakthrough test No.5.
......
.....
6.
Ion-exchange breakthrough test No.7. .
..........
7.
Ion-exchange breakthrough test No.8. . . . .
.......
8.
Ion-exchange breakthrough test No.9.
.....
.........
9.
Ion-exchange breakthrough test No. 10
...........
10.
Ion-exchange breakthrough test No.3.
.....
. . . .
. . . . .
11.
Ion-exchange breakthrough test No.6.
.....
. . . .
. . . . .
12.
Ion-exchange breakthrough tests - degree of fluoride exhaustion and
regeneration. . . . . . . . . . . . . . . . . . . . . . . . .
13.
Ion-exchange breakthrough tests - degree of nitrate exhaustion and
regeneration. . . . . . . . . . . . . . . . . . . . . . . . .
14.
System 1: Basic ion-exchange system for removal of fluorides and
nitrates. . . . . . . . . . . . . . . . . . . . . . . . . . .
15.
System 2: Surge-tank ion-exchange system for removal of fluorides
an.d nitrates. . . . . . . . . . . . . . . . . . . . . . . . .
System 3: Dual ion-exchange system for removal of fluorides and
nitrates. . . . . . . . . . . . . . . . . . . . . .
. . . . .
Prototype fluoride and nitrate waste treatment system. .
. . . . .
Pilot centrifuge system for removal of calcium fluoride from lime-
treated process solutions. . . . . . . . . . . . . . . . . . .
vii
Page
8
11
12
13
14
15
16
17
18
19
20
22
23
25
27
29
32
35
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Number
29.
FIGURES (cont. )
19.
Rototherm evaporator system for concentration of calcium nitrate in
lime-treated process solutions. . . . . . . . . . . . . . . . .
20.
Countercurrent flow in Rototherm evaporator system.
. . . .
. . . .
21.
Gearchem pump used with pilot evaporation system. .
.....
22.
Steam generator used with pilot evaporation system. . .
23.
Material cost relationship for lime treatment and evaporation to remove
nitrate versus calcium nitrate sales. . . . . . . . .
24.
Long Island vegetable research farm of Cornell University .
.....
25.
Glasshouse containing calcium nitrate fertilizer test setup. . . . . .
26.
Lettuce grown with calcium nitrate fertilizer obtained from treated
aluminum deoxidizer solution. . . . . . . . . . . . . . . . . .
27.
Lettuce grown with normal strength calcium nitrate fertilizer
obtained from treated nitric-hydrofluoric acid descaling solution
and standard calcium nitrate. . . . . . . . . . . . . . . . . .
28.
Lettuce grown with 1. 5 times normal strength calcium nitrate
fertilizer obtained from treated nitric- hydrofluoric acid
descaling solution and standard calcium nitrate .
Nitrate-nitrite manifold. . . . . . . . . . . . . . . .
......
viii
Page
40
42
43
44
51
52
54
55
56
57
64
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Number
TABLES
1
Properties of Ion-Exchange Treatment Materials. . .
. . . . .
2
Titanium Chemical-Milling Rinse Water Analysis. . .
. . . .
3
Summary of Exhaustion and Regeneration Conditions. . . . . .
4
Summary of Breakthrough Data. .
. . . .
..........
5
Results of Rinse Water Treatment.
.............
6
Heavy- Metal Cation Reduction. .
.................
7
Evaluation of Amberlite IRA-400 Resin .
...........
8
Capital Investment for Two-Stage Ion-Exchange Systems.
. . . . . .
9
Typical Industrial Uses of Metal-Processing Solutions
. . . . . . .
10
Composition and Uses of Fluoride- and Nitrate- Containing Processing
Solutions. . . . . . . . . . . . . . . . . . . . . . . .
11
Lime-Treatment Results for Chemical Processing Solutions and
Ion- Exchange Regenerant. . . . . . . . . . . . . . . . .
12
Rototherm Evaporator System - Pilot Evaluation at Grumman
Facilities (Evaporator Operated with Ambient-Temperature
Feed) . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
13
Calcium Nitrate Impurities Determined by Optical Emission
Spectroscopy. . . . . . . . . . . . . . . . . . . .
. . . . .
14
Rototherm Evaporator System - Pilot Evaluation at Artisan Facilities
(HF-HN03 Titanium Descaling Solution-Preheated (1000C/2120F)
Feed). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
Operating Temperatures - Rototherm Evaporator System - Pilot
Evaluation at Artisan Facilities (HF-HN03 Titanium Descaling
Solution) . . . . . . . . . . . . . . . . . . . . . . . .
16
Operating Temperatures - Rototherm Evaporator System - Pilot
Evaluation at Grumman Facilities. . . . . . . . . . . . .
ix
Page
8
9
10
10
21
21
24
26
31
34
37
39
45
45
47
48
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Number
D-1
TABLES (cont. )
17
Flexural and Compressive Strength Test Results for Regular and
Sludge-Containing Concretes. . . . . . . . . . . . . . . .
Average Response of Lettuce to Various Treatments. . .
. . . .
x
Page
58
70
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ACKNOWLEDGMENTS
This grant with Grumman Aerospace Corporation, Bethpage, New York, was
conducted by the Advanced Materials and Processes Development Section, Mr.
Carl Micillo, Manager. The program was directed by Mr. Christian J. Staebler,
Jr. The laboratory investigators for the program were Mr. Guenter Baumann, Mr.
John Masek, Mr. Einar Hoel and Mr. Edward Murray. Mrs. Bonnie Simpers as-
sisted in the engineering evaluation of the ion-exchange and nitrate removal and re-
covery sections. Chemical analyses of the solutions were performed by Mrs.
Teresa Yang, Mr. Angel Andino and Mr. Boleslaus Chojnowski of the Chemical
Engineering Section, Materials and Processes Engineering Department.
The assistance provided by Mr. Leo Monte of Artisan Industries, Inc., Mr.
William E. Bornak of Rohm and Haas, Mr. Donald Ingram of the Minerals, Pig-
ments and Metals Division of pfizer, Inc., and Mr. William F. Torreyson, Jr.,
Alcoa, is greatly appreciated. Special recognition is given to Dr. G. W. Selleck
and Dr. P. A. Schippers, Long Island Vegetable Research Farm of the Cornell
University Agricultural Experiment Station, Riverhead, N. Y., for their efforts in
evaluating the recovered calcium nitrate fertilizer.
The support of this project by the Office of Research and Development,
Environmental Protection Agency, and the help provided by Dr. Hugh B. Durham,
Environmental Scientist, EPA Industrial Environmental Research Laboratory,
Cincinnati, Ohio, is acknowledged with sincere thanks..
xi
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SECTioN 1
INTRODUC TION
A steadily increasing number of applications for titanium, super-alloys, refrac-
tory metals and aluminum in military and commercial projects is making it necessary
to expand the use of fluoride- and nitrate-containing solutions for cleaning, de-
oxidizing, descaling and other chemical operations. Mounting public concern about
environmental pollution and more stringent government regulations have put increased
pressure on metalworking industries to use non-polluting fluoride and nitrate waste
disposal procedures.
The increasing volumes of fluoride- and nitrate-containing processing solutions
and rinse waters being generated, however, are making existing methods of disposing
of these solutions prohibitively expensive. Most aerospace firms use vendors to dis-
pose of waste solutions. Because vendors may sometimes use questionable treatment
and disposal methods, the firms which supplied the waste solutions can be held respon-
sible for vendor-caused pollution damage. Also, because vendors may not normally
regenerate fluoride and nitrate wastes, the pollution problems may merely be trans-
ferred from one location to another. This project was initiated, therefore, to develop
a comprehensive fluoride and nitrate waste treatment technology for chemical process-
ing solutions and rinse waters used in the aerospace and metalworking industries.
The fluoride and nitrate treatment approach was based on the use of lime precipitation
and mechanically aided evaporation for process solutions and ion-exchange for rinse
waters.
1
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SECTION 2
CONCLUSIONS
. Pilot testing of the two-stage ion-exchange treatment system under repeated
exhaustion and regeneration conditions showed that Rohm and Haas Amberlite
IRA-400 resin in conjunction with Alcoa F-1 activated alumina is an effective
ion-exchange system for removal of fluorides and nitrates from process solu-
tion rinse waters and conditioning of rinse waters for recycle.
. Process solution rinse waters having average influent fluoride and nitrate
levels of 12 ppm and 60 ppm, respectively, can be reduced to fluoride and
nitrate levels of less than 3 ppm and 10 ppm, respectively, using ion-ex-
change treatment.
. Physical and chemical property tests performed on the Amberlite IRA-400
resin after 10 cycles of exhaustion and regeneration showed that there was no
decrease in resin capacity compared to starting material.
. Any silica fouling of the Amberlite IRA-400 resin can be reduced or elimi-
nated by using hot caustic 400C (120oF) to regenerate the resin.
. The ion-exchange regeneration waste from the Amberlite IRA-400 resin and
the F-1 activated alumina can be treated by addition of dry lime, followed by
solids separation for fluoride removal and mechanically aided evaporation for
nitrate removal and concentration.
. Typical aerospace and metalworking industry chemical processing solutions
such as nitric-hydrofluoric acid descaling, aluminum deoxidizer, and alodine
aluminum conversion coating can be treated to final effluent fluoride and
nitrate concentrations of less than 1 and 5 ppm, respectively.
. Chemical granular quicklime (CaO) is the most effective low-cost material for
fluoride and dissolved-metal treatment of acid-containing chemical process
solutions .
. Chemical and mechanical property tests showed the potential feasibility of
using calcium fluoride sludge as a strength-maintaining additive for concrete.
. The nitrate concentration of lime-treated and separated effluents of spent
chemical process solutions was reduced from 28,000 to less than 5 ppm by
passing these effluents through a thin-film mechanically aided evaporator.
. Calcium nitrate recovered from the thin-film mechanically aided evaporator
proved to be an effective plant fertilizer. Greenhouse tests conducted in
2
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conjunction with Cornell University's Extension Research Farm showed the
potential growth-enhancement that could be achieved.
. A steam economy of 80% was achieved in the thin-film mechanically aided
evaporator for concentration of the nitrate containing influent to 50% solids at
feed rates up to 155 kg/hr. m2 (32 Ib/hr. ft2).
. The cost breakeven point for waste treatment materials (lime and steam)
versus sale of recovered calcium nitrate at the current selling price, $330/
metric ton ($300/ton), occurs at 6000 ppm nitrate in the evaporator feed.
Nitrate evaporator feeds containing 38,000 ppm of nitrate would show a cost
advantage of $0. 05/1 ($0. 19/9al).
. Data generated in the studies to remove fluorides and nitrates from process
solutions and rinse waters made it possible to prepare production scale-up
plans.
3
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SECTION 3
RECOMMENDA TIONS
This technology development program established the pilot data required to pre-
pare production scale-up plans for a waste treatment system capable of removing
fluorides and nitrates from chemical process solutions and rinse waters used by the
aerospace and metalworking industries. This program also made it abundantly clear
that a production-scale demonstration program should be carried out next to verify the
economic and treatment quality aspects of the pilot waste treatment process.
If the following development efforts were performed, aerospace and metalwork-
ing firms would be able to implement the fluoride and nitrate waste treatment process
in their production plants with a high degree of confidence:
. Operating parameters have been developed for pilot operation of the waste
treatment system and scale-up of these parameters has been predicted; ver-
ification of these operating parameters should be made on a production facil-
ity in order to show that scale-up has resulted in the optimum operation with
respect to effluent quality and economics for each of the process solutions
being tested. Operating parameters that should be considered include feed
flow rates, treatment levels, separation levels, hold times and recycle capa-
bilities.
. Feasibility of a continuous operation treatment system using in-line mixers
for process waste reaction with lime and polyelectrolyte additions should be
determined. Incorporation of an automatic control system should be evaluated
to ensure treatment level reliability and fail safe operation.
. Quality control test requirements necessary to maintain optimum performance
for the various treatment steps must be established.
. Further evaluation of polyelectrolyte flocculant requirements to determine
separation performance is recommended. The effects of these flocculants on
re-use of calcium fluoride as a concrete additive or phase-change material
and calcium nitrate as a fertilizer should also be determined.
. Requirements for final effluent treatment before re-use or discharge, such
as pH adjustment and filtration to remove suspended solids, should be deter-
mined, and specific procedures for this treatment should be established.
. Economic analysis for the finalized treatment system design should be made
including equipment, labor and utilities to provide a complete basis for in-
dustry acceptance of the proposed treatment design.
4
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. Additional field testing of the waste calcium nitrate fertilizer should be per-
formed to verify plant yield, nitrogen present in plant during various growth
stages, residual soil nitrogen, change in soil pH and toxicity, if any.
. The calcium fluoride waste should be evaluated as a low-cost phase-change
material for thermal energy storage. Development efforts would include
establishing additives to form a eutectic, phase diagrams, heat of fusion,
thermal conductivity, containment materials, effect of impurities and com-
pound stability.
. The following information must be established before concrete containing
calcium fluoride sludge can be used for construction:
- Maximum amount of sludge that Gan be added to maintain or increase con-
crete strength
- Short- and long-term aging strength through structural testing
- Long-term leachability, slump, air content and degree of strength degrada-
tion due to environmental exposure.
. The applicability of tbe fluoride and nitrate waste treatment system to other
aerospace and metalworking industry wastes should be established. Where
necessary, treatment techniques should be developed and tested to provide
complete waste treatment procedures for these solutions.
5
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SEC TION 4
ION-EXCHANGE TREATMENT OF RINSE WATERS
FOR FLUORIDE AND NITRA TE REMOVAL
APPROACH
This phase of the program was directed toward the removal of fluorides and
nitrates from rinse waters so that they may be recycled or disposed of in a non-
polluting condition. The approach taken involved two- stage ion-exchange treatment --
the first for fluoride and nitrate removal, and the second for pH adjustment and
fluoride polishing.
STUDY AREAS
Pilot evaluation of the ion-exchange operating parameters for fluoride and ni-
trate removal involved the following:
. Set-up of the materials and equipment
. Development of column exhaustion and regeneration procedures
. Generation of breakthrough data
. Establishment of pH and heavy-metal cation control
. Evaluation of resin stability
. Determination of production scale-up and economic factors.
BACKGROUND
Two-stage, ion-exchange treatment of titanium chemical-milling rinse waters to
remove fluorides and nitrates was shown to be feasible by the initial EPA/Grumman
program, "Treatment and Recovery of Fluoride Industrial Wastes," Project S800680
(12070HGH). Two, 1982-cm3 (0.07-ft3) columns -- one containing Rohm and Haas
Amberlite IRA-400 ion-exchange resin and the other Alcoa F-l activated alumina--
were used in series for fluoride and nitrate removal, and fluoride polishing and pH
adjustment, respectively. This laboratory evaluation showed that the fluoride content
of titanium chemical-milling rinse waters was reduced to less than 1 ppm, thereby
permitting recycling or disposal into discharge basins of the treated rinse waters. As
a result, pilot testing of the two-stage, ion-exchange treatment system was recom-
mended to determine operating parameters for production implementation. These
were evaluated in terms of breakthrough capacity and the exchange capacity of the
6
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resin for the influent system under study. Knowledge of the breakthrough capacity
makes production scale-up possible.
EQUIPMENT AND MATERIALS
Two, O. 02832-m 3 (1-ft3) acrylic columns, 15.2 cm (6 in) in diameter by 2.0 m
(80 in) high, were used for the pilot tests. Valves and piping were made from poly-
vinyl chloride plastic. The system (Figure 1) was designed to permit operation of
the columns either in series or individually to facilitate regeneration.
Rahm and Haas' Amberlite IRA-400 ion-exchange resin was selected to remove
fluorides and nitrates from rinse waters based on the results of the previous program.
Alcoa's F-1 activated alumina was used in series with the Amberlite IRA-400 ion-ex-
change resin because the previous program had shown that it did polish fluorides and
adjust the pH to the process level. This made it possible to re-use the process rinse
waters, even though Alcoa F-1 activated alumina did not remove a significant amount
of fluorides from the rinse waters (see material properties in Table 1).
DETERMINATION OF COLUMN OPERATING PARAMETERS
Procedure
Determination of equilibrium breakthrough capacity was accomplished by sub-
jecting the columns to repeated exhaustion and regeneration cycles. Fluoride and ni-
trate concentrations, pH and conductivity were monitored during each exhaustion
cycle. Breakthrough capacity was determined as the point at which fluoride and nitrate
concentrations in the effluent exceeded 3 and 10 ppm, respectively.
A standard rinse water solution was prepared from concentrated solutions to
give the average fluoride and nitrate concentrations, 12 and 60 ppm, respectively, in
the actual titanium chemical-milling rinse water. Trace amounts of heavy-metal
cations were also included to simulate the production rinse water (Table 2).
Exhaustion and Regeneration
Flow rate of the test rinse water ranged from 1. 9 to 5.7 l/min (0.5 to 1. 5 gpm)
for each of the exhaustion cycles which involved 2,300 to 3,000 1 (600 to 800 gal) of
influent. Samples taken during the exhaustion cycle were analyzed for fluoride and
nitrate concentrations, pH and conductivity. Column regeneration was accomplished
by passing 68 1 (18 gal) of 4% sodium hydroxide (NaOH) solution through the Amberlite
lRA-400 resin at a rate of 1.9 l/min (0.5 gpm). The column was then rinsed with 189
1 (50 gal) of water at a rate of 1. 9 l/min (0.5 gpm). Alcoa's F-1 activated alumina
required 136 1 (36 gal) of 4% sulfuric acid (H2S04) passed through at a rate of 1. 9
l/min (0.5 gpm) for regeneration. This was followed by a 189 1 (50 gal) water rinse
at a rate of 1.9 l/min (0.5 gpm). Samples taken during regeneration were analyzed
for fluoride and nitrate concentrations and pH to determine the degree of regenera-
tion (see test conditions in Table 3).
BREAKTHROUGH CAPACITY
Breakthrough capacity to reduce fluoride: nitrate concentration from 12:60 ppm
to less than 3:10 ppm was determined on ten exhaustion cycles. Seven of these cycles
-------
1i1
iii
I
--~
ROHM & HAAS
AMBER LITE
IRA-400
RESIN
fI
~"'.'.f.""".'-
.!. '
. <'
. .
/' ~ ~'
.
. "
.".~~
. "., ~~~4
- '. ..
:1}
~-
Figure 1.
Two-stage ion-exchange system for rinse water treatment.
TABLE 1.
PROPERTIES OF ION-EXCHANGE TREATMENT MATERIALS
Material
Property
Amberlite I RA-400 lon-Exchange
Resin
F-1 Activated Alumina
. Chemical: Strongly basic material consisting of an 8%
crosslinked polystyrene matrix of the trimethylbenzyl-
ammonium type
. Bulk Density: 700 kg/m3 (44 Ib/ft3)
. Size: 297-841 microns (50-20 U. S. standard mesh)
. Void Volume: 40-45%
. Moisture Content (drained): 42-48% by weight
. Chemical: Porous form of aluminum having a high
su rface area
. Bulk Density: 880 kg/m3 (55 Ib/fe)
. Size: 2.38-6.35 mm (8 U. S. standard mesh to 1/4 inch)
. Moisture Content (drained): 44% by weight
8
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TABLE 2. TITANIUM CHEMICAL MILLING RINSE WATER
ANAL YSIS
Concentration, ppm
Ion Range Avg
F- 1 - 36 12
NO;(N) 23 - 120 60
AI 0.5- 6.7 1.9
Ti 1.5 - 9.9 4.2
V < 0.4 - 0.9 0.4
Fe 0.2 - 1.8 0.5
Mn < 0.5 - 0.5 <0.5
Cu 0.3 - 0.9 0.5
Zn < 0.1 - 0.2 0.1
were run at 1. 9 l/min (0.5 gpm), two at 5.7 l/min (1. 5 gpm) and one at 3.8 l/min
(1. 0 gpm). Because the re~in was supplied in a super-regenerated state (400 kg
NaOH/m3 resin or 25 lb/ft ), the first cycle at 1. 9 l/min (0.5 gpm) and the second
cycle at 3.8 l/min (1. 0 gpm) showed a high breakthrough capacity - greater than
2,270 I (600 gal) (Figures 2 and 3).
Subsequent tests at 1. 9 l/min (0.5 gpm) showed that the average breakthrough
capacity was 1,820 1 (480 gal) Jor fluoride and 1,630 1 (430 gal) for nitrate (Table 4,
Figures 4 through 9). These capacities will be used for scale-up to production levels.
Test data at 5. 7 l/min (1. 5 gpm) showed that breakthrough capacity does not vary
significantly with flow rate in this range (Table 4, Figures 10 and 11). As a result,
this flow rate will be used for production scale-up to minimize resin requirements.
Additional testing over a wider range of flow rates is needed, however, to more
clearly define the effect of flow rate on breakthrough capacity.
Although changes in the influent concentration may slightly affect breakthrough
capacity, the laboratory studies from the initial program showed that occasional con-
centration spikes (to 60 ppm of fluoride) can be treated to reduce fluoride concentra-
tion to the required level (less than 3 ppm) with the resin volume designed for the
standard influent concentration (12 ppm of fluoride). Thus, a system designed to
handle the average concentration can be expected to handle occasional concentration
spikes.
Regeneration also affects the exchange capacity of the resin. At a regeneration
level of 96 kg NaOH/m3 (6 Ib/ft3) of Amberlite IRA-400 resin, the total anion exchange
capacity is 25.2-27.5 kg CaC03/m3 (11-12 kgr/ft3) of resin. The breakthrough ca-
pacity under these conditions represents an exchange capacity usage of 75% of the total
capacity, including the water background (silica, alkalinity and free-mineral acidity).
Use of hot (49<>C/1200F) caustic regeneration may increase the exchange capacity
9
-------
TABLE 3. SUMMARY OF EXHAUSTION AND REGENERATION CONDITIONS
Test Condition
Column Volume, cm3 (ft3)
Influent
Concentration: 12 ppm F-/60 ppm N03" (N)
pH: 2.7
Conductivity: 120-2,000 tlmho/cm
Amberlite I RA-400
28,320 (1)
F-' Activated Alumina
28,320 (1)
Exhaustion
r-o
o
Flow Rate: 1.9-5.7 l/min (0.5-1.5 gpm)
Regeneration
Regenerant Concentration
Flow Rate, I/min (gpm)
Level, kg/m3 (lb/ft3) regenerant/resin
Rinse Rate, I/min (gpm)
Rinse Water Usage, I (gal)
4% NaOH
1.9 (0.5)
96 (6)
1.9 (0.5)
190 (50)
4% H2S04
1.9 (0.5)
192 (12)
1.9 (0.5)
190 (50)
TABLE 4. SUMMARY OF BREAKTHROUGH DATA
12
3
No.
Flow Rate, Breakthrough Capacity, I (gal) of
I/min (gpm) Range Avg Tests *
1.9 (0.5) 1420-2080 1820 (480) 6
(375-550)
5.7 (1.5) 1700-1800 1700 (450) 2
(450~ 75)
1.9 (0.5) 1325-1890 1630 (430) 6
(350-500)
5.70.5) 1610-1700 1700 (450) 2
(425~50)
Ion
Fluoride
Ion Concentration, ppm
Influent Breakthrough
Nitrate
60
10
*Does not include tests affected by super-regeneration of resin as supplied by the manufacturer.
-------
1.2
F
r
I
1.1
.8
.7
CICo
.6
~
~
.3
.2
.1
o
pH
LEGEND:
C =CONCENTRATION OF F- OR NO; (N)
IN EFFLUENT
Co =CONCENTRATION OF F- OR NO; (N)
IN INFLUENT
CONDUCT ANCE
FLUORIDE
(200)
(400)
2000
1000
EFFLUENT VOLUME, LITERS (GAL)
7
6
5
pH
600 4
a:
w
f-
w
::2; 500 3
i=
z
w
~ 400 2
en
o
x
::2;
0 300
a:
(J
::2;
w' 200
(J
z
~
f-
(J
::) 100
a
z
I 0
(J
xl 0
~I FLUORIDE
~I
~I
~
~I
~I
FLOW RATE = 1.9 L/MIN (0.5 GPM)
NITRATE
(600)
3000
(900)
Figure 2. Ion-exchange breakthrough test no. 1.
-------
I
1.2 I
I
1.1
1.0
.9
.8
.7
C/co
.6
r-'
l\:I
.5
.4
.3
,
.2 ,
,
.1
o
LEGEND:
C ;CONCENTRATION OF F- OR NO; (N)
IN EFFLUENT
Co ;CONCENTRATION OF F- OR NO; (N)
IN INFLUENT
NITRATE
FLUORIDE
(200)
1000
pH
I
II
gl
01
~I
~I
~I
~I
LLI
.'!I
z
1-(")1
o
z
CONDUCTANCE
7
6
5
pH
600 4
a:
w
I-
w
:2 500 3
I-
Z
w
c
( 400 2
C.
I
:2
0
a: 300
u
:2
W 200
u
Z
-------
1.2 I
I
1.1 pH I
1.0 I I
.9 I I
.8 I I
.7 I I
I I
.6
I-' Clco
""
.5 NO;(N) BREAKTHROUGH I
I
.4 F' BREAKTHROUiH I
.3 I I
FLUORIDE
.2 I I
.1
0
LEGEND:
C ; CONCENTRATION OF F- OR NO; (N)
IN EFFLuENT
Co; CONCENTRATION OF F- OR NO; (N)
IN INFLUENT
NITRATE I
(200)
1000
(400)
EFFLUENT VOLUME, LITERS (GAL)
2000
(600)
Figure 4.
Ion-exchange breakthrough test no. 4.
6
5
a: pH
LU
f- 600 4
LU
:2:
f-
Z
LU 500 3
u
en
0
I
:2: 400 2
o
a:
u
:2: 300
LU'
U
z
4:
f- 200
u
:J
0
Z
0 100
u
0
3000
FLOW RATE; 1.9 L/MIN (O.5GPM)
-------
7
6
pH
II:
~600 5
w
::2
I-
Z 500 4
I W
I u
en
I I ~400 3
::2
I 0
I 5 300 2
I ::2
u.i
I al ~ 200
«
I-
U
I ~I 5 100
z
0
J: I~I u
0
t:) « I
:J W
10 I II:
II: IXII
~IU.
II ~ I
IXI
~I
'f I
1.2
1.1
1.0
.9
.8
.7
C/Co
...... .6
*'"
.5
.4
.3
.2
.1
0 NITRATE
CONDUCT ANCE
LEGEND:
C ;CONCENTRATION OF F- OR NO;.(N)
IN EFFLUENT
Co ;CONCENTRATION OF F- OR NO; (N)
IN INFLUENT
(200)
1000
(400)
EFFLUENT VOLUME, LITERS (GAL)
Figure 5.
FLOW RATE ;1.9L/MIN (0.5GPM)
2000
(600)
3000
Ion-exchange breakthrough test no. 5.
-------
1.2
1.1
pH
1.0
.9
.8
.7
CICo
.6
......
01 .5
.4
.3
.2
.1
NITRATE
o
pH
CONDUCTANCE
I F' BREAKTHROUGH
NO;(NIBREAKTHROUGH
LEGEND:
C = CONCENTRATION OF ",- OR NO; (N) I
IN EFFLUENT
Co = CONCENTRATION OF F- OR NO; IN)
IN INFLUENT
NITRATE
FLUORIDE
700 6
ffi 600 5
~
w
~
i= 500 4
~ pH
(J
en
o 400 3
I
~
o
a:
(J 300 2
~
w
(J
z 200
-------
1.2
1.1
pH
1.0
.9
.8
CICo
.7
.6
I-'
~
.5
.4
.3
.2
.1
NITRATE
o
I I F" BREAKTHROUGH
NO; (N) BREAKTHROUGH I
I I
I I
I I
I I
I
I I
(200)
1000
(400) 2000
EFFLUENT VOLUME, LITERS (GAL)
Figure 7.
Ion-exchange breakthrough test no. 8.
6
a:: 600 5
UJ
f-
UJ
~ pH
f- 500 4
z
UJ
u
en 400 3
0
I
CONDUCT ANCE ~
0
a:: 300 2
u
~
UJ"
u 200
z
<(
f-
U
:)
0 100
z
0
u
0
LEGEND:
C ;CONCENTRATION OF F- OR NO; (N)
IN EFFLUENT
Co ;CONCENTRATION OF F- OR NO; (N)
IN INFLUENT
FLOW RATE; 1.9L/MIN (O.5GPM)
(600)
3000
-------
1.3
1.2
1.1
1.0
.9
.8
.7
C/Co
.6
I--'
-::J
.5
.4
.3
.2
.1
o
I
I
I I
I :
I I
NO; (N) BREAKTHROUGH I I
I I
F BREAKTHROUGH I
I I
I
I
I
LEGEND:
C = CONCENTRATION OF F- OR NO; IN}
IN EFFLUENT
Co =CONCENTRATION OF F- OR NO; (N)
IN INFLUENT
800 7
IX:
w 700 6
I-
w
:2:
I-
Z 600 5
w
u
en pH
O
J: 500 4
:2:
o
IX:
U
:2: 400 3
w'
u
z
« 300 2
I-
U
~
0
z 200
0
u
100
0
(200)
(600)
FLOW RATE = 1.9L!MIN (0.5GPM)
NITRATE
1000
2000
EFFLUENT VOLUME, LITERS (GAL)
Figure 8.
Ion-exchange breakthrough test no. 9.
3000
-------
1.3,
1.2
1.1
1.0
.9
.8
I
.7 I
C/Co I
.6 I
I-' I
00
I
" I
.5 :>
o
a: I
I
I- I
.4 ~
«
UJ I
a:
ca I
I
.3 LL I
~
FLUORIDE I~M I
.2 0 I
z
I
.1
NITRATE
0
(200) 1000 (400)
CONDUCTANCE
pH
FLUORIDE
LEGEND:
C =CONCENTRATION OF F- OR NO; (N)
IN EFFLUENT
Co = CONCENTRATION OF F- OR NO; (N)
IN INFLUENT
800 7
700 6
a:
UJ
I- 600 5
UJ
:2
I- pH
z
UJ 500 4
u
en
0
I
:2 400 3
o
a:
u
:2 300 2
UJ"
u
z
«
I- 200
u
:>
0
z
0 100
u
0
(600)
3000
FLOW RATE = 1.9L1MIN (O.5GPM)
Figure 9.
Ion-exchange breakthrougn test no. 10.;
2000
EFFLUENT VOLUME, LITERS (GAL)
-------
1.2
1.1
1.0
.9
.8
.7
C/Co
.6
I-'
~ .5
.4
.3 I
I
.2 I
,
.1
o
pH
LEGEND:
C =CONCENTRATION OF F- OR NO; (N)
IN EFFLUENT
Co =CONCENTRATION OF F- OR NO;(N)
IN INFLUENT
FLUORIDE
NITRATE
(200)
1000
EFFLUENT VOLUME, LITERS (GAL)
2000
(600)
:I:
(.'J
~ I I
~ I al
a: I :::>
m ~I
Iu.. :I:
0'/111-
- ~
z «
~MI ~I
z ,
u..
(400)
I
I I
I I
I I
I I
I I
I I
I I
Figure 10.
Ion-exchange breakthrough test no. 3.
6
5
pH
a:
UJ 600 4
I-
UJ
:2:
I-
Z 500 3
UJ
u
en
0
:I: 400 2
:2:
0
a:
u
:2: 300
UJ'
u
z
« 200
I-
U
:::>
0
z 100
0
u
0
FLOW RATE = 5.7L!MIN (1.5GPM)
3000
(900)
-------
1.2
1.1
1.0
.9
.8
.7
C/Co
N .6
o
.5
.4
-800 7
700 6
a:
w
I-
w 600 5
:2
I- pH
z
w
u 500 4
en
o
J:
:2
0 400 3
a:
u
:2
ui 300 2
u
z
I
I 0
z
0
I u 100
I
g 1131 0
0 ::> NITRATE
~ I ~I
~ ~
~ Iii
~MI ~I
z
I
FLOW RATE = 3.7 L/MIN (1.5GPM)
CONDUCTANCE
LEGEND:
C = CONCENTRATION OF F- OR NO; (N)
IN EFFLUENT
C =CONCENTRATION OF F- OR NO; (N)
o INFLUENT
.3
.2
FLUORIDE
.1
NITRATE
o
(200)
1000
(400)
2000
(600)
EFFLUENT VOLUME. LITERS (GAL)
Figure 11.
Ion-exchange breakthrough test no. 6.
-------
usage, because of the tendency to increase the removal of ions deposited on the resin
during the previous exhaustion (Figures 12 and 13). This regeneration condition is
also necessary for effective removal of silica from the resin.
Rinse water usage following regeneration should be increased to maximize
fluoride removal at the start of the next exhaustion. Insufficient rinsing causes the
initial influent to complete the rinse, thus increasing fluoride leakage in the initial
volume of influent (Figures 5 through 9 and 11).
pH AND HEAVY-METAL CATION CONTROL
Trea1ment of the rinse water with Amberlite IRA-400 ion-exchange resin in-
creased the pH from about 3 to 10. Use of F-1 activated alumina in series with
Amberlite IRA-400 resin maintained the pH at about 4 (Table 5), allowing the rinse
water to be recycled in the system. Trea1ment of the rinse water also reduced the con-
centration levels of the heavy-metal cations (Table 6). As a result, build-up of these
cations in the recycled rinse water is expected to be minimal.
TABLE 5. RESULTS OF RINSE WATER TREATMENT
Parameter
Influent
Effluent
pH
Conductivity, micromhos/centimeter
Fluoride Concentration, ppm
Nitrate Concentration, ppm
2-4
120 - 2000
12
60
3-5
60 - 600
1 - 3
1 - 10
TABLE 6. HEAVY METAL CATION REDUCTION
Ion
Concentration, ppm
Before Treatment After Treatment
AI
Ti
0.9
4.2
0.6
0.4
3.1 *
< 0.3
0.08
< 0.1
Cu
Fe
(*Increase is probably due to leaching from activated alumina)
21
-------
tV
tV
r (0.1)
1500 -
EXHAUSTION
(0.08)
i=
o
o
u.
U
m~
::::>u.
U«
a:z
w-
o..~
en::::>
O...J
Z«
::::>0
Ow
0..1-
-«
a:>
w-
1-1-
wU
~«
u~
~~
U«
a: a:
w-
o..w
WI-
0-
_...J
a: a:
OW
::::>ID
...J~
u.«
u.u.
00
en
2;
«
a:
t:)
FLUORIDE RECOVERED
BY ACTIVATED ALUMINA
6
RUN NO.
7
2
3
4
5
8
9
10
Figure 12.
Ion-exchange breakthrough tests - degree of fluoride exhaustion
and regeneration.
-------
N
IN
7000
(0.4)
6000
5000
(0.3)
~
o
~ 4000
U...
OOu.
:>«
Uz
ffi~
~ 3(0.2)
o«~
zo
:>w
2!;i:
->
ffii=
~~
:2: ~ 2000
uo
Qj~
~ « (0.1)
a:
a:-
Ww
11..1-
I:!::i 1000
«a:
a:w
!::;
z«
u.u.
00
U)
:2:
«
a:
C)
o
EXHAUSTION
REG ENE RATION
TOTAL IRA & ALUMINA
NITRATE RECOVERED
BY ACTIVATED ALUMINA
2
3
4
6
9
10
Figure 13.
5
RUN NO.
lon-exchange breakthrough tests - degree of nitrate exhaustion
and regeneration.
7
8
-------
RESIN STABILITY
Physical and chemical properties of the spent Amberlite lRA-400 resin were
evaluated after completion of the ten exhaustion/regeneration cycles to determine the
resin stability in this system. Although significant silica fouling and slight bead
breakage did occur, the total resin capacity did not decrease from the initial value
(Table 7). Silica fouling can be reduced by increasing the regeneration temperature
from ambient to 49°C (120°F). This increase in the regeneration temperature should
also help to maintain a high breakthrough capacity.
TABLE 7. EVALUATION OF AMBERLITE IRA-400 RESIN
Spent Resin.
Property 28,320 cm3 New Resin
(1 ft3) Test
Moisture Holding Capacity, % 50 43 - 49
Whole Bead Content, % 77 90
Organic Fouling None None
Silica (Si02) Cone, ppm 1,146 None
Weak-Base Capacity, meq/g (dry) 0.46 0.4 (min)
Strong-Base Capacity, meq/g (dry) 3,66 3.6 (min)
Total Anion Exchange Capacity, meq/g (dry) 4.12 3,8 (min)
Fines through 50 Mesh, % 4,1 3 (max)
PRODUCTION SCALE-UP AND ECONOMIC CONSIDERATIONS
The technical base established in the pilot treatment study is sufficient to design
a production-scale system for treatment of rinse waters containing about 12 ppm of
fluorides and 60 ppm of nitrates. Design can be based on the maximum flow rate
studied, 5.7 l/min (1. 5 gpm), using the breakthrough capacity of 60,150 1 (influent)/
m3 (resin) (450 gal/ft3). Including an 80% efficiency factor, about 1. 2 m3 (42 ft3) of
resin would be needed to handle a rinse-water waste-stream of 190 l/min (50 gpm).
The capital investment for a system of this size, including two ion-exchange
columns, piping, tankage and a small control system, would be about $25,000. Re-
quirements for systems of other capacities are also presented (see Table 8).
Several system designs should be considered for the specific production opera-
tion involved to optimize the initial capital investment and the operating costs. Three
possible systems are described below.
System 1 - Basic Ion-Exchange System (Figure 14)
This system is designed for a specific operation with regeneration on the off-
shift.
24
-------
FLAKE CAUSTIC
9
HEATING~
COIL
I:,:)
01
RINSE WATER
12 PPM F; 60 PPM N
4% NAOH
120°F
H20 (HOT)
BACKWASH
Figure 14.
4% H2S04
F.1
ACTIVATED
ALUMINA
H20
BACKWASH
)
CONC H2S04
~
TO RINSE TANKS
< 3 PPM F
< 10 PPM N
System 1: Basic ion-exchange system for removal of fluorides
and nitrates.
IRA.
400
RESIN
\.
"
TO REGENERANT WASTE TREATMENT
-------
Advantages
. Requires minimum capital investment
. Good for infrequent or irregular operation
. Can recycle effluent.
Disadvantages
. Resin volume may not be optimum for flow rate involved because it must be
designed to fit the operating schedule
. Additional capital investment would be required to accommodate capacity in-
creases or changes in operating schedules.
TABLE 8. CAPITAL INVESTMENTS FOR TWO-STAGE ION-EXCHANGE SYSTEMS
Rinse Water Flow Rate,
I/min (gpm)
Resin Volume,
m3 (ft3 )/eolumn
Approximate
Capital Investment, *
$
38(10)
190(50)
380(100)
0.26(9)
1.2(42)
2.4(84)
10,000
25,000
40,000
(* Includes two ion-exchange columns, two regenerant solution tanks,
associated piping and pumps, small control system, installation
and materials.)
System 2 - Surge Tank Ion-Exchange System (Figure 15)
This system incorporates a surge tank to accumulate the influent during column
regeneration.
Advantages
. Permits continuous feed to system
. Requires minimum capital investment for continuous operation, especially at
low flow rates
. Can recycle effluent.
Disadvantage
. Additional capital investment would be required to accommodate capacity in-
creases or changes in operating schedules.
26
-------
FLAKE CAUSTIC
~
HEATING J
COIL
t-:I
-::J
RINSE WATER
12 PPM F
60 PPM N
4% NAOH
1200 F
H20 (HOT)
BACKWASH
Figure 15.
!
SURGE
TANK
4% H2S04
F-1
ACTIVATED
ALUMINA
H20
BACKWASH
CONC H2S04
l~
TO RINSE TANKS
< 3 PPM F
< 10 PPM N
System 2: Surge-tank ion-exchange system for removal of fluorides
and nitrates.
IRA
400
RESIN
TO REGENERANT WASTE TREATMENT
-------
System 3 - Dual Ion-Exchange System (Figure 16)
This system incorporates two sets of ion-exchange columns installed so that one
set can be operated while the other set is being regenerated.
Advantages
. Provides continuous operation
. Resin volume may be somewhat less than required for a single set of columns
. Capacity increase is readily available
. Minimum downtime for maintenance
. Effluent can be recycled.
Disadvantage
. Requires large capital investment.
Selection of the optimum system design depends on equipment costs (tankage
versus columns), cycle length (exhaustion versus regeneration) and operating schedule.
Optimization of the capital investment through system selection should be included with
the other operating costs (labor, utilities, raw materials and regenerant treatment)
to give a complete economic evaluation.
28
-------
RINSE WATER
12 PPM F
60 PPM N
4% NAOH
120°F
(FROM MAKE.UP
TANK)
(HOT) H20
BACKWASH
IRA-
400
RESIN
F-1
ACTIVATED
ALUMINA
\.
Figure 16.
" I
4% H2S04
H20
BACKWASH
TO RINSE TANKS
< 3 PPM F
< 10 PPM N
...
FLAKE CAUSTIC
CONC H2S04
H20
TO REGENERANT WASTE TREATMENT
H20
HEATING
COIL
MAKE.
UP
TANK
IRA.
400
RESIN
H20 (HOT)
BACKWASH
F-1
ACTIVATED
ALUMINA
I
System 3: Dual ion-exchange system
for removal of fluorides and nitrates.
29
-------
SECTION 5
REMOVAL AND RE-USE OF FLUORIDES AND NITRATES
FROM LIME-TREATED EFFLUENTS
APPROACH
This phase of the program was directed toward the removal and recovery of
fluorides and nitrates from spent, metal-treatment acid solutions, and ion-exchange
regeneration wastes in an effort to prevent ground-water pollution. The treatment
approach involved lime-precipitation and solids separation of fluorides and metallic
elements, mechanically aided evaporation to recover nitrates, and application of re-
covered nitrates as plant fertilizer. The solutions evaluated were similar to those
used throughout the metalworking industry for cleaning, descaling and pretreatment
(see typical industrial uses for these types of solutions in Table 9).
STUDY AREAS
The following technical efforts were involved in the development of precipitation
and evaporation techniques to remove fluorides and nitrates from chemical processing
solutions:
. Design of prototype treatment system
. Lime treatment and fluoride removal by centrifugation
. Removal of nitrates by evaporation from lime-treated effluents
. Use of evaporator sludge as nitrogen fertilizer.
DESIGN OF PROTOTYPE TREATMENT SYSTEM
Removal of fluorides and nitrates from spent processing solutions requires sev-
eral treatment steps. A prototype treatment system (Figure 17) was designed based
on studies conducted during this program. Although other system designs could be
used for fluoride and nitrate removal, the system selected incorporates the treatment
steps evaluated in Phases I and II of this program. Lime-treatment of various spent
processing solutions requires different application levels and hold-times before sep-
aration. These treatment variations were studied in Phase I. Flocculant additions to
increase solids removal were studied briefly in Phase I. Additional work is needed,
however, to determine the applicability and effectiveness of this treatment step.
Separation of suspended solids (calcium fluoride and metals) by centrifugation was
evaluated in this study. Other solids separation techniques, such as rotary vacuum
filtration or tank settling, are also feasible. Removal of dissolved solids (calcium
30
-------
TABLE 9.
TYPICAL INDUSTRIAL USES OF METAL-PROCESSING SOLUTIONS
Application
Chemical Pollutants Building Consumer
Process Generated Aerospace Automotive Construction Products Marine
Aluminum Deoxi- Fluorides, Skins, Fasteners, Trim, Decorative Strip Line Coil Cans, Utensils Superstructures,
dizer and Conver- Nitrates, Structural Coating, Painted Coating, Siding, Boats, Canoes
sion Coating Chromates, Components Parts Gutters, Storm
Heavy Metals Windows
~ Ferrous Alloy Fluorides, Structural Com- Chrome-Plated and Steel Sid ing, Ornamental Iron, Hull Components,
I-'
and Titanium Nitrates, ponents, Wire Painted Parts, Wire I-Beam and Fence Nails, Fasteners, Hardware, Fasteners
Descaling Chromates, Cleaning Cleaning, Wire Utensils
Heavy Metals
Etching and Chem- Fluorides, Heavy Aircraft and Printed Circuits Pretreatment, Printed Circuits, Submarine
ical Milling Metals, Sulfides Missile Skins, Architectural Name Plates Superstructures
Jet Engine Parts Trim and Subcomponents
Plating Cyanides, Fluor- Hard Chrome land- Bumpers, Hub Caps, Heavy, Equipment, Costume Jewelry, Engine Parts.
ides, Chromates, ing Gears, Clips, Trim, Knobs, Handles Nails, Bolts, Hardware Appliances, Cleats, Hardware,
Heavy Metals Brackets, Heat- Bicycles, Lamps, Trim
Treated Parts Tools, TV's, Radios,
-------
~~
FEEDER
LN
N
CALCIUM
NITRATE
FERTILIZER
HOLDING TANK
:t[\t~fi;:fA:~
',SLAKER .::
:;i.;:::"::~',:,,:,:,,:,:-:;:~:
pH CONTROLLER
I--
I
I
I
I
COMMAND
-----
----
1---
I
r--t---
I I
I I
I
I
--
.,
I
1
r--.J
I
I
I
I
I
I
WASTE
HF & HN03 &
HN03-HF
1500 GAL
I LIME
I HOLDING &
FEED TANK'
I 500 GAL
I
L
MECHAN ICALL Y
AIDED
EVAPORATOR
Figure 17.
IN LINE MIXER
NEUTRAL-
IZA TION
TANK
1500 GAL
VACUUM FILTER
OR PRESSURE FILTER
CONVEYOR BELT
(~.
~{¥r~~~I¥¥*',
~BOX
"::.0,::.",".::;.",",",;"
1
PURIFIED WATER I
DISCHARGE L
--------
Prototype fluoride and nitrate waste treatment system.
SENSOR
---
---
-.
1
I
I
I
I
I
ELECTRO I
LYTE
I 50 GA L I
I
I
I
I
I
I
I
I
I
CALCIUM FLUORIDE
CONCRETE ADDITIVE
OR PHASE CHANGE
- ~A~A=-- - J
-------
nitrate) from the centrate by mechanically aided evaporation was studied in Phase IL
The calcium nitrate evaporator sludge was evaluated for use as a nitrate fertilizer in
an effort to reduce disposal costs and provide some return on material costs.
LIME TREATMENT AND FLUORIDE REMOVAL BY CENTRIFUGATION
The lime treatment and centrifugation techniques developed in the initial pro-
gram were used to generate test material for the pilot evaporator studies from tita-
nium descaling, Amchem 7-17 deoxidizer, Alodine aluminum conversion coating and
ion-exchange regeneration waste solutions (Table 10).
Pilot Centrifuge Setup and Calibration
A Sharples/Fletcher Mark III centrifuge (Figure 18) manufactured by the
Pennwalt Corporation was used for all laboratory pilot testing. This centrifuge,
which has a 35. 6 cm (14 in)-diameter by 15.2 cm (6 in)-high basket and a speed capa-
bility of 3250 rpm, is designed for separation studies and performance analyses to
generate data for projected production equipment. The pilot centrifuge system con-
sists of the following components:
. 208-1 (55-gal) tank with Lightnin AG-100 air-powerea mixer for making up
lime slurry
. V ant on PY-60 centrifugal pump to transfer lime to treatment tank
. Treatment tank with Holloway Super electric mixer and Jabsco P-6 centrifu-
gal feed pump
. 114-1 (30-gal) polyvinyl chloride rectangular tank to receive treated effluent
(at rear of centrifuge)
. 208-1 (55-gal) drum to receive sludge skimmed from centrifuge bowl
The Sharples/Fletcher Mark III centrifuge is completely variable in speed over
the 0-3250 rpm range. The Sharples division of the Pennwalt Corporation recom-
mended that testing be conducted at a force of 1300G and flow rates of up to 3.8 l/min
(1. 0 gpm). The centrifuge speed necessary to obtain the 1300G force was calculated
as follows:
Centrifugal force in multiples of the force of gravity
= (5.59 x 10-4) (Bowl speed in rpm)2 (Bowl diameter in centimeters)
= (1. 42 x 10-5) (Bowl speed in rpm)2 (Bowl diameter in inches)
Bowl speed = 2550 rpm
Bowl diameter = 35. 6 cm (14 in)
33
-------
TABLE 10.
COMPOSITION AND USES OF FLUORIDE AND NITRATE-CONTAINING PROCESSING SOLUTIONS
Nitrate/Fluoride-Containing Process
SaIutions - Typical Formulations
Typical Uses
Manufacturer
AMCHEM Products Inc., Ambler, Pa.
Aluminum Deoxidizer Solution
18-56g11 AMCHEM (2-6 oz./gal.)
7-17 deoxidizer (contains potassium
dichromate and fluoride salts)
10-20% volume nitric acid 1.4 kg/I
(420 Baume)
cc
~
Titanium Descaling Solution
35-45% volume nitric acid 1.4 kg/I
(420 Baume)
Actane #70 1.5-3% by weight
or
Hydrofluoric acid 1.5-3% by volume,
using 70% weight acid
Aluminum Conversion Coating
Solution (Alodine). Alodine contains
chromic acid and complex fluoride
salts.
lon-exchi:mge regeneration waste
H2 S04 regeneration waste
NaOH regeneration waste
Cleaning of aluminum parts prior
to:
. Conversion coating (Alodine)
. Masking of parts for chemical
milling
. Spot welding
Cleaning of titanium parts for:
. Welding
. Removal of heat-treat scale
. Painting
Used to produce a protective
coating on aluminum to:
. Increase corrosion resistance
. Increase paint adhesion
Regeneration of:
Activated alumina
IRA 400 used to treat process
rinse waters
Chemical grade acids (sources open)
Actane #70 - Enthone Inc., West
Haven, Connecticut
AMCHEM Products, Inc., Ambler, Pa.
In-house
-------
"
\
\
:1
CENTRIFUGE
FEED TANK
I
'I.t
U" -"
ii" ~
-y.
j
....
7
-" ~
~
CENTRIFUGE
Figure 18.
Pilot centrifuge system for removal of calcium fluoride from
lime-treated process solutions.
35
-------
Lime Slaking
Chemical granular quicklime, which was found to provide optimum fluoride and
metal ion removal from the solutions studied in the initial program, was used for all
tests in this program. A slurry concentration of 0.24 kg lime/l water (20.3 lb lime/
gal water) was used for all process solution pilot testing. Dry, chemical granular
quicklime was added to the ion-exchange regeneration solution because of its low
fluoride and nitrate concentrations, 73 and 650 ppm, respectively. The lime slaking
time of 25 to 30 minutes gave a 490C (1200F) solution temperature rise above am-
bient temperature.
Titanium Descaling Solution Treatment
Eighty-seven-l (23-gal) batches of titanium descaling solution having fluoride
and nitrate concentrations of 117,000 and 64,000 ppm, respectively, were treated with
123 1 (32.5 gal) of lime slurry. After the lime-treated solution was mixed for one
hour, its pH was 10.2 and its temperature was 820C (1800F). After standing for 18
hours, the lime-treated solution was again mixed and fed to the centrifuge at a rate of
1. 9 l/min (0.5 gpm).
Aluminum Deoxidizer Solution Treatment
The concentrations of fluoride, nitrate and hexavalent chromium in the untreat-
ed, Amchem 7-17 aluminum deoxidizer solution were 1,500, 26,000 and 5,500 ppm,
respectively. To reduce the hexavalent chromium to trivalent chromium, 2.3 kg
(5 lb) of sodium metabisulphite were added to 114 1 (30 gal) of the Amchem 7-17
solution. After 64 1 (17 gal) of lime slurry were added, the solution was mixed for
one hour and allowed to stand for 18 hours. The treated solution was again mixed and
fed to the centrifuge at a rate of 1. 9 l/min (0. 5 gpm).
Aluminum Conversion Coating Solution Treatment
Alodine 600 aluminum conversion coating solution was treated in conjunction
with Amchem 7-17 aluminum deoxidizer solution because of its low nitrate (N) con-
centration (250 ppm) and its infrequent dumping (once per year). A mixture of 28.4 I
(7.5 gal) of Alodine 600 solution and 28.41 (7.5 gal) of Amchem 7-17 solution
was treated with 1.1 kg (2.5 lb) of sodium metabisulphite to reduce the hexavalent
chromium (3,000 ppm) to trivalent chromium. Complex fluorides (e. g., BF 4 - fluo-
borates) contained in the Alodine 600 solution were decomplexed by adding 700 g (1. 5
lb) of aluminum sulfate. Previous experiments had shown that 12 g aluminum sulfate-
/1 solution (O.llb/gal) would dissociate 300 ppm of fluoride (F-) from the fluoborate
(BF4-). The Alodine 600/Amchem 7-17 mixture was mixed for one-half hour and al-
lowed to stand for 18 hours. Addition of 32.2 I (8. 5 gal) of lime slurry to the mix-
ture brought the pH to 11. 5. The mixture was then agitated for one hour and allowed
to settle for 18 hours. After the treated solution was mixed for one minute, it was
centrifuged at a rate of 1. 9 l/min (0.5 gpm).
Ion-Exchange Regeneration Waste Treatment
A mixture of various regenerant solutions from the ion-exchange tests was
treated. This 1. 3 pH mixture, which consisted of 30. 3 I (8 gal) of sulfuric acid
36
-------
TABLE 11. LIME-TREATMENT RESULTS FOR CHEMICAL
PROCESSING SOLUTIONS AND ION-EXCHANGE REGENERANT
Initial Dissolved
Concentration, Soiution- Temp. Effluent Solids After
ppm To-Slurry* Rise During Effluent Concentration, ppm Fluoride
Solution (F) (N) Ratio Treatment, °c (OF) pH (F) (N) Removal, %
HF-HN03 117 ,000 64,000 1: 1.4 38 (100) 10.2 3 28,000 14.9
Descaling
Coo-' AMCHEM 7-17 1,500 26,000 1 :0.6 10 (50) 11.5 3 19,000 11.4
-.:J Aluminum
Deoxidizer
AMCHEM 7-17 2,000 34,500 1 :0.6 10 (50) 11.5 3 23,000 14.1
Aluminum
Deoxidizer
& Alodine 600
lon-Exchange 73 600 100 Grams/ 12.7 5 600 3.3
Regeneration Liter (Dry)
Waste
*Slurry: 0.24 kg CaO/1 (2.0 Ib/gal.)
-------
regenerant and 15.1 I (4 gal) of sodium hydroxide regenerant, had fluoride and ni-
trate concentrations of 73 and 600 ppm, respectively. Addition of 4. 5 kg (10 lb) of
dry calcium oxide (CaO) to the solution mixture raised the pH to 12.7 after being
mixed for one hour. After standing for 24 hours, the mixture was centrifuged at
a rate of 1. 9/min (0.5 gpm).
Summary of Results
The results obtained when calcium oxide (chemical granular quicklime) was
used to treat three chemical processing solutions and an ion-exchange regeneration
waste are summarized (Table 11). These tests showed that treatment of titanium
descaling solution, aluminium deoxidizer solution and ion-exchange regeneration
waste with lime removes fluorides and dissolved metallic constituents to give an
effluent having a fluoride concentration of 3 to 5 ppm. The Alodine 600 aluminum
conversion coating/aluminum deoxidizer solution required preliminary treatment with
aluminum sulfate to decomplex the fluoborates. Secondary treatment of this solution
with lime slurry removed dissolved metals and produced an effluent having a fluoride
concentration of 5 ppm.
The lime-treated effluents with their resultant fluoride and nitrate levels
(Table 11) were used as feed solutions for mechanically aided evaporation tests.
After mechanically aided evaporation, final effluents containing less than 1 ppm of
fluorides and 5 ppm of nitrates were produced (see Table 12).
REMOVAL OF NITRATES FROM LIME-TREATED EFFLUENTS
Background
Lime-treatment and centrifugation of fluoride and nitrate waste solutions re-
moves calcium fluoride but leaves calcium nitrate in solution. Separation of calcium
nitrate from solution by evaporation produces discharge water with less than 5 ppm
of nitrates and a concentrated calcium nitrate solution (heavy liquid) that can be used
as a plant fertilizer. Pilot testing showed that separation of nitrates by evaporation
is feasible for waste solutions containing 600 to 28,000 ppm of nitrates (N) or 3 to
15% of solids after lime treatment. Four solutions (Table 11) were studied in this
phase of the program.
Equipment
A Rototherm evaporation system (Figure 19) supplied by Artisan Industries,
Inc., Waltham, Massachusetts, was used for the pilot tests. The Rototherm E unit
is a thin-film, mechanically aided evaporator with a ribbon blade rotor. A 0.12-m2
(1. 31-ft2) rising film pre-evaporator feeds the O. 09-m2 (1. o-ft2) Rototherm unit.
Vapors are condensed in a O. 95-m2 (10.2-ft2) shell-and-tube condenser. This type
of evaporator was selected because it can handle thick liquors more effectively than
other types. Countercurrent flow (Figure 20) was used throughout the system. Feed
rate was controlled by a Gearchem Model G4-ACK-KKA gear pump (Figure 21) sup-
plied by the Eco Pump Corporation, South Plainfield, New Jersey. This positive-
displacement pump provided excellent feed rate control without any mechanical dif-
ficulties during pilot testing. An upstream filter was used to prevent pump damage.
38
-------
TABLE 12. ROTOTHERM EVAPORATOR SYSTEM - PILOT EVALUATION AT GRUMMAN FACILITIES
(EV APORATOR OPERATED WITH AMBIENT-TEMPERATURE FEED)
Feed Feed Rototherm Evaporation Steam Evap Distillate Bottoms
Test Cone, Rate, Steam Temp, Capacity, Economy, Level, Concentration Concentrati on,
Solution No. ppm N kg/In (lb/hr) °C(oF) kg/hr (lb/hr) kg evap/kg steam % ppm N ppm F ppm N
Ca(N03 h 1 27200 17.2(37.9) 133(272) 12.1 (26.6) 81.8 70.2 4.2 140000
Standard 2 27200 13.4(29.5) 162(323) 9.7(21.3) 76.6 72.2 2.6 128000
Test 3 27200 13.1 (28.9) 167(332) 10.0(22.0) 76.9 76.1 3.1 140000
Solution
HN03-HF 4 28000 16.3(36.0) 113(235) 10.3(22.6) 81.6 62.7 1.0 <1 115600
Titanium 5 28000 15.6(34.3) 114(237) 10.6(23.3) 82.6 67.9 1.3 <1 150300
Descaling 6 28000 15.6(34.4) 114(237) 9.7(21.4) 80.8 62.2 0.7 <1 168900
Solution 7 28000 16.6(36.5) 111 (232) 9.9(21.8) 80.7 59.5 0.3 <1 135400
AMCHEM 7-17 8 19000 13.7(30.2) 169(336) 11.5(25.3) 78.3 83.8 2.6 <1 197000
Coo:! Aluminum 9 19000 14.1(31.1) 164(327) 10.5(23.2) 81.1 74.6 1.0 <1 233000
to Deoxidizer 10 19000 13.9(30.7) 149(301) 10.0(22.1) 77.8 72.0 0.8 <1 233000
Solution 11 19000 15.5(34.1) 132(270) 10.5(23.1) 79.7 67.7 0.8 <1 191000
12 19000 17.8(39.1) 119(247) 10.4 (23.0) 77.7 58.8 0.8 <1 11 0000
13 19000 14.5(31.9) 131(268) 10.4(23.0) 80.9 71.5 1.0 <1 164000
Alodine 600 14 23000 13.2(29.1) 151(303) 9.7(21.4) 79.3 73.5 2.0 <1 203000
Aluminum 15 23000 13.4(29.5) 154(310) 9.8(21.5) 78.8 72.8 3.8 <1 204000
Conversion 16 23000 13.4(29.5) 149(300) 9.0(19.8) 76.4 66.9 2.7 <1 222000
Coating
Solution &
AMCHEM 7-17
Deoxidizer
lon-
Exchange 17 600 12.2(26.8) 167(332) 11.8(26.0) 80.0 96.8 0.2 <1
Regeneration 18 600 11.8(25.9) 149(300) 10.2(22.5) 80.4 87.1 0.1 <1 36000
Waste 19 600 10.0(22.0) 133(272) 8.4(19.4) 81.4 83.4 0.1 <1 34000
-------
Figure 19. Rototherm evaporator system for concentration of calcium nitrate
in lime-treated process solutions.
40
-------
A steam generator (Figure 22) was used because high-pressure steam was not avail-
able at the laboratory test site. The Grumman and Artisan pilot testing facilities
were equivalent.
Operating Parameters
Both feed rate and steam pressure were varied during pilot evaluation of the
Rototherm evaporation system. Feed rates ranged from 9.1 to 36.3 kg/hr (20 to 80
lb/hr). In the preliminary pilot tests performed at the Artisan facilities, the feed
was preheated to 99-1030C (210-2170F) before it was allowed to enter the pre-evap-
orator. In the Grumman pilot tests, the feed remained at ambient temperature.
Process steam was introduced at pressures up to 900 kPa (130 psi absolute). The
evaporation system itself was operated at atmospheric pressure.
Test Procedure
The Rototherm evaporation system was used to determine whether lime-treated
waste solutions could be separated to give a liquid with less than 10 ppm nitrate (N)
and a sludge that could be used as a plant fertilizer. The effect of feed rate and steam
pressure on bottoms concentration, steam use and evaporation level was studied.
Several lime-treated processing solutions having nitrate concentrations ranging from
19,000 to 28,000 ppm and an ion-exchange regeneration waste containing 600 ppm of
nitrate (N) were used. The distillate in each test contained less than 5 ppm of nitrate
(N). The solutions had been treated with different lime concentrations to account for
variations in their initial fluoride and nitrate concentrations (see Table 11).
Evaporation to a point just before bottoms crystallization is desirable, because
this minimizes fertilizer shipping costs without creating significant evaporator foul-
ing. The feed rate for each test was adjusted to provide a reasonable bottoms con-
centration (i. e., heavy liquid without crystallization) averaging about 50% solids.
The nitrogen content in the solids is comparable to that found in nitrate fertilizers
(about 15%). The metals concentrations in the sludge were also comparable to those
occurring in commercial calcium nitrate (Table 13). Use of this byproduct as a plant
fertilizer was shown to be effective in tests performed at the Long Island Vegetable
Research Farm of Cornell University, Riverhead, New York. (See Section 5, Use
of Evaporator Sludge as Nitrogen Fertilizer, and Appendix D. )
Artisan Pilot Tests
Preliminary testing of the Rototherm evaporation system was performed at the
pilot facilities of Artisan, Inc., Waltham, Massachusetts, to determine the feasi-
bility of using this system and to establish initial operating conditions for further
testing. Lime-treated, nitric-hydrofluric acid titanium descaling solution was used
in these tests. An evaporation level of 70% was required to concentrate the 15%
solids feed to 50% solids sludge. The feed was preheated to 1000C (212oF) for each
of the tests. Although the distillates contained up to 50 ppm of nitrates (N), the
Grumman pilot tests showed that nitrate levels less than 5 ppm (N) could be obtained
consistently with this system (see test results and temperature profiles in Tables 14
and 15, respectively).
41
-------
COOLING WATER
*'"
~
CONDENSER
ENTRAINMENT
SEPARATOR
STEAM
DISTillATE
..
SUPPORT
STAND
MOTOR
Figure 20.
Countercurrent flow in Rototherm evaporator system.
STEAM
PRE-EVAPORATOR
CONDENSED
. STEAM
FEED
-------
Figure 21.
L
J,*, ~
. ,
.
.
'"
Gearchem pump used with pilot evaporation system.
43
-------
\ ~~. ,',
I 1
! f <'!p -..
i ~ "----
1l,! ..-..
I
I
I~ JIJIi8( T
i:- ~~' --~
u
.-
.. ".
'~'':+. fP'.
~......-.::::;;;'co
.
~ TEMPERATURE
RECORDER
-..""....'"
-'
,/
~~
Figure 22.
Steam generator used with pilot evaporation system.
44
-------
TABLE 13. CALCIUM NITRATE IMPURITIES DETERMINED BY OPTICAL EMISSION SPECTROSCOPY
Calcium Nitrate Composition, %
Ca(N03 h Source Na Ti V AI Sn Mn Cu Fe
Aluminum Deoxidizer Sludge (13.6%N; 55.6% Solids) 0.1 <0.1 <0.1 < 0.1 <0.1 <0.1 <0.1 <0.1
HN03 - HF Descale Sludge (17.4%N; 62.5% Solids) <0.1 <0.1 <0.1 <0.1 <0.1 < 0.1 <0.1 < 0.1
Commercial Ca(N03 h <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 < 0.1
Artisan Pilot Test Sludge <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1
Reagent Grade Ca(N03)2 <0.1 <0.1 <0.1 <0.1 <0.1 < 0.1 <0.1 <0.1
TABLE 14. ROTOTHERM EVAPORATOR SYSTEM - PILOT EVALUATION AT ARTISAN FACILITIES
( HF-HN03 TITANIUM DE SCALING SOLUTION PREHEATED (lOOOC/2120F) FEED )
.p.
t.n Feed Pre-Evaporator Rototherm Evaporation Steam Evap Distillate
Test Rate, Steam Temp, Steam Temp, Capacity, Economy, Level, Concentration,
No. kg/hr (lb/hr) °C(OF) °C(OF) kg/hr (lb/hr) (kg evap/kg steam) % ppm N
1 17.3(38.2) 144(291) 102(215) 11.4(25.2) 100 66.0 12
2 20.6(45.3) 144(291) 102(215) 12.8(28.1) 100 62.3 30
3 29.3(64.6) 143(290) 102(216) 13.2(29.0) 99.7 44.8 26
4 24.1(53.0) 150(302) 103(217) 14.5932.0) 99.4 60.5 22
5 22.7(50.0) 154(309) 103(217) 14.9(32.8) 99.4 65.7 21
6 28.4(62.5) 142(287) 122(252) 17.2(37.8) 96.7 60.5 24
7 28.1(61.8) 140(284) 138(280) 19.7(43.5) 94.6 70.4 17
8 27.8(61.2) 140(284) 158(317) 20.6(45.4) 90.7 74.4 12
9 23.5(51.7) 140(284) 163(326) 20.4(44.9) 90.4 86.7 25
10 35.7(78.7) 158(317) 17.7(38.9) 94.2 49.4 52
11 34.3(75.6) 157(315) 163(326) 26.5(58.3) 90.5 77.3 36
12 29.5(65.0) 157(314) 176(348) 24.7(54.4) 89.5 83.6 52
13 26.8(59.0) 158(316) 173(344) 22.2(49.0) 89.1 83.0 30
14 22.4(49.3) 158(316) 174(345) 17.8(39.1) 88.0 79.3 15
15 9.9(21.8) 175(347) 8.5( 18.8) 89.1 86.2 2
-------
Pre- Evaporator Evaluation
To test the pre-evaporator, the system was started up without turning on the
Rototherm rotor. The pre-evaporator steam was run at 143-1540C (290-3100F) with
feed rates of 17.2-29.5 kg/hr (38-65 Ib/hr). Evaporation levels of 45 to 66% were
achieved at a steam economy of 99% (Table 14, Tests 1-5 and 10). To achieve the
evaporation level desired (about 70%), the feed rate would have to be reduced below
17.2 kg/hr (38 lb/hr) using the pre-evaporator only.
Rototherm Evaluation
Evaluation of the Rototherm evaporation system was accomplished using steam
temperatures of 121-1770C (250-350oF) at feed rates of 22.7-34.0 kg/hr (50-75 Ib/hI).
In this case, evaporation levels ranged from 60 to 87%. More than 70% evaporation
(Table 14, Tests 7-9 and 11-14) was obtained at steam temperatures above 1380C
(2800F). Optimum operating conditions were found to be those of Test 11 (Table 14)
in which 77% evaporation was achieved at 34.3 kg/hr (75.6 Ib/hr) of feed. This re-
quired a steam pressure of 690 kpa (100 psi absolute).
Grumman Pilot Tests
Pilot testing of the Rototherm evaporation system was completed at Grumman's
test facility using a rented unit. The Rototherm evaporator system was set up in
conjunction with the centrifugal treatment system described previously. Tests were
conducted on a standard calcium nitrate solution prepared from commercial calcium
nitrate, as well as on three process solutions (Table 11) and the ion-ex-change re-
generation waste solution. Ambient-temperature feed was used for each of these
tests. Test results and temperature profiles are presented (see Tables 12 and 16,
respectively) .
Standard Calcium Nitrate Solution
Feed rates of 12. 7 to 17.2 kg/hr (28 to 38 lb/hr) were tested at steam tempera-
tures of 133-1670C (272-3320F). The 70-76% evaporation levels that were achieved
(Tests 1-3, Table 12) were sufficient to concentrate the 15% solids feed to 50% solids
in the bottoms.
Titanium Descaling Solution
. In these tests, a low evaporation level (59 to 68%) was obtained because the
steam temperature was too low (113uC/2350F) and the feed rate too high (15.4-16.8
kg/hr or 34-37 lb/hr) to concentrate the solids from 15 to 50% (Table 12, Tests 4-7).
Aluminum Deoxidizer Solution
An acceptable evaporation level (greater than 75% for the 11% solids feed) was
obtained in these tests (Table 12, Tests 8-9) at the higher steam temperatures (164-
1680C/327-3350F) for f!3ed rates of 13.6-14.5 kg/hr (30-32 Ib/hr). Tests at higher
feed rates (15.4-17.7 kg/hr or 34-39 lb/hr. Tests 11-12, Table 12) and lower steam
temperatures (121-1490C/250-300oF, Table 12, Tests 10-13) gave low evaporation
levels (58 to 72%).
46
-------
TABLE 15. OPERATING TEMPERATURES - ROTOTHERM EVAPORATOR SYSTEM - PILOT EVALUATION AT
ARTISAN FACILITIES (HF-HN03 TITANIUM DESCALING OOLUTION)
Temp, °C(oF)
Test Pre-Evaporator Rototherm
No. Feed Distillate Bottoms Steam Steam
1 99(211) 103(218) 94(201) 144(291) 102(215)
2 100(212) 106(223) 96(204) 144(291) 102(215)
3 101 (213) 104(220) 101(214) 143(290) 102(216)
~ 4 101 (213) 106(223) 104(220) 150(302) 103(217)
-:I 5 101(213) 109(229) 107(225) 154(309) 103(217)
6 101 (213) 104(219) 107(224) 142(287) 122(280)
7 101(213) 106(222) 104(219) 140(284) 138(280)
8 101(213) 104(220) 143(290) 140(284) 158(317)
9 101(213) 116(240) 142(288) 140(284) 163(326)
10 103(217) 102(216) 98(208) 158(317)
11 102(216) 106(222) 145(293) 157(315) 163(326)
12 103(217) 108(226) 147(296) 157(314) 176(348)
13 102(215) 112(234) 146(295) 158(316) 173(344)
14 102(215) 132(270) 147(296) 158(316) 174(345)
15 101 (214) 101(214) 145(293) 175(347)
-------
TABLE 16. OPERATING TEMPERATURES - ROTOTHERM EVAPORATOR SYSTEM-
PILOT EVALUATION AT GRUMMAN FACILITIES
Temp, °C(oF)
Test Pre-Evaporator Rototherm
Solution No. Feed Distillate Bottoms Steam Steam
Ca(N03 h 1 28(82) 101(214) 125(257) 169(336) 133(272)
Standard 2 28(82) 102(215) 155(311) 171 (339) 162(323)
Test 3 28(82) 102(216) 157(314) 179(338) 167(332)
HN03-HF 4 29(83) 102(216) 118(245) 154(310) 113(235)
Titanium 5 28(83) 102(256) 124(256) 159(318) 114(237)
Descaling 6 28(83) 102(216) 127(260) 155(311) 114(237)
~ 7 29(84) 102(216) 118(244) 149(300) 111 (232)
00
AMCHEM 7-17 8 28(82) 102(216) 157(314) 169(336) 169(336)
Aluminum 9 28(82) 102(216) 160(320) 168(335) 164(327)
Deoxidizer 10 27(81) 103(217) 149(300) 158(317) 149(301)
11 27(81) 102(216) 132(270) 151 (304) 132(270)
12 27(81) 102(216) 138(280) 150(302) 119(247)
13 28(82) 102(216) 127(260) 150(302) 131(268)
AMCHEM 7-17 14 28(83) 103(217) 153(308) 161 (322) 151(303)
Aluminum 15 28(83) 103(217) 143(290) 162(324) 154(310)
Deoxidizer 16 28(83) 103(217) 132(269) 159(318) 149(300)
& Alodine 600
lon-Exchange 17 27(78) 102(216) 147(297) 170(338) 167(332)
Regeneration 18 26(78) 102(216) 152(303) 163(325) 149(300)
Waste 19 26(78) 102(216) 146(296) 156(313) 133(272)
-------
Aluminum Conversion Coating Solution
These tests, which were run at a steam temperature of 149-154oC (300-310oF)
and a feed rate of 13.2 kg/hr (29 lb/hr), showed that a steam pressure of 485 kPa (70
psi absolute) was borderline for this operation. The evaporation level dropped below
the acceptable level (70% at 14% solids feed) to 67% with insignificant variations in
steam temperature and feed rate (Table 12, Tests 14-16).
Ion-Exchange Regeneration Waste
Since the ion-exchange regeneration waste contains only 3% solids, it must be
evaporated 94% to obtain a 50% solids sludge. A feed rate of 12.2 kg/hr (27 lb/hr)
and a steam ~emperature of 1670C (3230F) gave the required evaporation level (Table
12, Test 17). Lower steam temperatures (132-1490C/270-300oF), however, did not
provide sufficient evaporation (83-87%) even at lower feed rates (10.0-11.8 kg/hr or
22-26 lb/hr, Table 12, Tests 18-19).
Summary of Evaporator Pilot Evaluation
The pilot test results provided sufficient information for production scale-up of
the evaporator system. A Rototherm steam pressure of 690 kPa (100 psi absolute)
was found to be optimum for concentrating a 3 to 15% solids influent to 50% solids.
A pre-evaporator steam pressure of 345 to 690 kPa (50 to 100 psi absolute) was also
found to be adequate for this operation. Using these steam pressures, ambient-
temperature feed at rates up to 14.5 kg/hr (32 lb/hr) can be processed to 50% solids.
The steam economy for evaporation of ambient temperature feed is 80%. Under these
steam conditions, feed rates up to 34.0 kg/hr (75 lb/hr) can be handled if the influent
is preheated to 1000C (212oF). In this case, a steam economy of 90% can be expected
in the pre-evaporator and Rototherm units.
Crystallization in the evaporator, which may cause fouling of the evaporator
heat-transfer surfaces, can be caused by using feed rates that are too low for the
evaporator conditions. Fouling of the heat-transfer surfaces did not occur during
pilot evaluation of the Rototherm evaporator system.
Evaporator Scale-Up and Economics
Scale-up of the evaporator system can be based on the evaporator economy,
feed rate and heat-transfer area. To handle a waste stream of 5,680 l/day (1,500
gal/day) containing 25,000 ppm of nitrates (N), a 1. 9-m2 (20-ft2), thin-film mechan-
ically aided evaporator with a 2. 4-m2 (26-ft2) pre-evaporator costing about $50,000
would be required. Steam at a pressure of 690 kPa (100 psi absolute) and at a rate of
1. 25 kg steam/kg distillate (1. 25 lb steam/lb distillate) would be used.
Analysis of the material costs required for treatment versus the sale price of
the calcium nitrate fertilizer produced indicates that a net gain in material costs can
be realized through lime treatment of nitrate-containing solutions. This is shown by
the following example:
. Disposal Volume - 100,000 I (26,420 gal) per year of process solutions con-
taining 35,000 ppm (N) and 10,000 ppm (F)
49
-------
. Lime Slurry Concentration - 0.24 kg CaO/1 (2.0 lb CaO/gal)
. Lime Treatment Level - 0.75 I of lime slurry/l of process solution (0.75
gal/gal)
. Lime Cost - $0. 035S/kg CaO ($32. 50/ton CaO)
. Annual Lime Cost - $640/year.
The lime-treated process solution is centrifuged to remove calcium fluoride and
excess lime. After centrifugation, the solution contains 20,000 ppm (N) and 11.6%
solids. The centrate is then evaporated to 50% solids at the following cost:
. Evaporator Economy - SO%
. Evaporation Level - 75%
. Steam Cost - $6.60/1,000 kg of steam ($3.00/1,000 lb of steam)
. Annual Steam Cost - $l,OSO/year.
The evaporator distillate contains less than 5 ppm (N) and is recycled or discharged.
The evaporator bottoms are sold as calcium nitrate fertilizer for $0. 33/kg of solids
($300/ton of solids) to give the following net gain:
. Annual Fertilizer Sales - $6,740/year
. Net Gain - $5,020/year.
The net gain does not include the savings realized by eliminating the cost of vendor
disposal of waste solutions. Lime treatment of waste solutions having nitrate con-
centrations as low as 6,000 ppm (N) provides a breakeven point for material costs
(Figure 23).
USE OF EVAPORATOR SLUDGE AS NITROGEN FERTILIZER
The feasibility of using evaporator sludge as nitrogen fertilizer was studied.
This type of fertilizer would not be used at the start of the growing season because it
does not supply potassium and phosphorous as a complete fertilizer does. It could
be used as a sidedress or topdress fertilizer, however, during later growth stages.
The use of fertilizer is instrumental in increasing crop yields and reducing growing
costs. Because high energy inputs are required for fertilizer manufacture and
because a critical worldwide shortage of fertilizer currently exists, use of recovered
calcium nitrate sludge as a plant fertilizer would help to alleviate both situations.
The Long Island Vegetable Research Farm of Cornell University, Riverhead,
New York (Figure 24), evaluated calcium nitrate sludge obtained from treated nitric-
hydrofluoric acid desoaling and Amchem 7-17 aluminum deoxidizer solutions. The
two sludge samples were compared with certified ACS calcium nitrate obtained from
the Fisher Scientific Company, Fair Lawn, New Jersey. Four varieties of lettuce
were grown in a hydroponic culture in a glasshouse (Figure 25). Each type of fertil-
izer was used in a solution at normal strength and at 1. 5 times normal strength.
50
-------
(1001t/GAL)
----
2
o (10.01t/GAL)
i=-
:>2
...JQ
01-
rn:>
rn...J
rnO
Wrn
g~
a: W
CL.U
a:0
W a:
I- CL.
2~
""t:J
1-" ;;
~ - (1.01t/GAL)
U
1.01t/L
I-
2
o
CL.
2
W
>
W
~
«
W
a:
CD
10.01t/L
0.11t/L
(O.11t/GA L)
100
1000
10,000
100,000
NITRATE CONCENTRATION BEFORE LIME TREATMENT, PPM
Figure 23.
Material cost relationship for lime treatment and evaporation to
remove nitrates vs. calcium nitrate sales.
51
-------
/ . ~~T'"
/ I. - ," , /. - ,I
/ ~7n
. ' .,_/:-:::. >'': ~
. ,. .;' " .;' v ...-7-
L'~ . 1/~X
;Yo' ,.6- .~'" 1
-"'..-- ;:~:.~:~. ~7i/,' -/1'
~ . -- ,I
, -...----., ,
,
,/ . I
/~
/
-'
/
..
"
~.
Figure 24.
Long Island Vegetable Research Farm of Cornell University.
52
-------
Little variation was observed in the appearance of plants grown in the various
fertilizer solutions (see Figures 26, 27 and 28). Differences in the plant type and
growing medium (front to back in Figures 26-28) are apparent, though. The Long
Island Vegetable Research Farm drew the following conclusion from their study:
"No distinction could be made in growth of the plants, in yield of fresh material,
in N-uptake by the plants, in dry matter content of the plants or N-content of the
dry matter between plants grown in either of the experimental solutions or in the
pure laboratory chemical. "
Several other important attributes of the calcium nitrate sludge fertilizer were
observed in this study. First, although phototoxicity is more evident in plants grown
in a hydroponic system than those grown in soil, no trace of toxicity was present in
plants grown with the sludge fertilizer. Second, because nitrogen fertilizer would be
applied in later growth stages, soil leaching and contamination of groundwater would
be minimized. Third, acidity of normally acid soils would be reduced upon repeated
application of the sludge fertilizer - a beneficial effect for most crops. Details of
the experiments conducted by the Long Island Vegetable Research Farm are contained
in Appendix D.
CALCIUM FLUORIDE SLUDGE RE-USE
Re-use of calcium fluoride sludge as an additive to concrete was evaluated as a
potential alternative to disposal of the sludge in landfills. This is becoming increas-
ingly more important as landfill sites are being filled and disposal regulations are
becoming more stringent. Sludge re-use in concrete would also eliminate the costs
associated with landfill disposal.
The viability of the re-use concept, however, was dependent on whether the
calcium fluoride sludge would maintain or increase the strength of the concrete. This
was determined in the previous program. Flexural and compressive strength spec-
imens were prepared from a standard concrete mixture and mixtures containing var-
ious percentages of calcium fluoride sludge as replacements for part of the concrete
and part of the sand (Table 17). The specimens were tested in accordance with
standard ASTM procedures. Test results (Table 17) indicate that flexural and com-
pressive strengths are maintained if the calcium fluoride sludge is used only as a
partial replacement for the sand while the percentage of cement in the concrete mix-
ture is kept at the standard level (26.7%).
Leachability tests were also conducted to determine the extent of fluoride loss
that would result from continuous exposure of the modified concrete to running water.
Two liters (0.53 gal) of tap water were recirculated over a 45-g (0. l-lb) sample of
Sludge Concrete Mixture No.2 (see Table 17) for two weeks. An insignificant in-
crease in fluoride content (0.068 to 1.7 ppm) occurred.
Additional testing will be required before calcium fluoride sludge recovered from
lime-treated chemical process solutions can be used commercially. The strength
and leachability tests did show, however, that addition of calcium fluoride sludge to
concrete mixtures is a feasible waste disposal method that will reduce pollution dis-
posal costs and dependency on landfill sites.
53
-------
FERTILIZER SOLUTION
FEED PUMPS
-- ~~-",--'
Figure 25. Glasshouse containing calcium nitrate fertilizer test setup.
54
-------
H
R
~~
Figure 26.
Lettuce grown with calcium nitrate fertilizer obtained from treated
aluminum deoxidizer solution.
55
-------
I#~ tJo ~.~
¥ ill
1iIii\!j
"
Figure 27.
Lettuce grown with normal-strength calcium nitrate fertilizer
obtained from treated nitric-hydrofluoric acid descaling solution
and standard calcium nitrate.
56
-------
. '11
Figure 28.
Lettuce grown with 1.5 times normal strength calcium nitrate
fertilizer obtained from treated nitric-hydrofluoric acid descaling
solution and standard calcium nitrate.
57
-------
TABLE 17. FLEXURAL AND COMPRESSIVE STRENGTH TEST RESULTS
FOR REGULAR AND SLUDGE-CONTAINING CONCRETES
Average Average
Flexural Compressive
Strength Strength
Ratio of kPa kPa
CJ1 Mixture Cement Percentage of Percentage of Percentage of (psi) (psi)
00
No. To Solids Cement Sand Sludge 3 Tests 6 Tests
1 :2.75 26.7 73.3 0 :3820 16100
(554) (2330)
2 1:3.16 24.1 66.4 9.5 2640 11800
(383) (1705)
3 1:2.75 26.7 66.5 6.8 3790 20000
(550) (2895)
-------
BIBLIOGRAPHY
Abrams, J. M., and L. Benezia. 1967. Ion-Exchange Polymers. Reprinted from
Encyclopedia of Polymer Science and Technology. John Wiley & Sons Inc.
Artisan Test Center. 1974. Tests in a Rototherm Evaporator on a Calcium Nitrate
Solution for Grumman Aerospace Corporation. Waltham, Massachusetts.
Beckman Instruments, Inc. Beckman Technical Data Sheet No. 1735-A. November
1968. Fluoride Ion Electrode. Scientific Instruments Division, Fullerton, Cali-
fornia 92634.
Boruff, C. S., et ale Absorption of Fluoride from Salts by Alum Floc. Industrial
and Engineering Chemistry, Volume 29, No. 10.
De Moura, J. 1969. Specific Ion Electrodes Used to Study Interactions of Glucose-
I-Phosphate and Mg++ and F -. Arch. Biochem. Biophys. University of Idaho,
Moscow, Idaho. 134 (1), p. 258-9.
Diamond Shamrock Chemical Company. 1969. Duolite Ion Exchange Manual. 2nd Ed.
Environmental Protection Agency. 1971. Methods for Chemical Analysis of Water
and Wastes.
Halbedel, H. S. 1971. Acid Fluorides and Safety. Technical Sheet No. 768. The
Harshaw Chemical Company. p. 1975.
Kolthoff, I. M. and E. B. Sandell. Textbook of Quantitative Inorganic Analysis,
3rd Ed. p. 58.
Kuzyakin, E. B., et ale Relationship of the Settling Rate of Waste Water Precipitants
to the Ionic Composition during their Defluorination with Lime, Aluminum Sulfate,
and Polyacrylamide.
Leithe, W. 1948. Oxidimetric Nitrate Analysis of Fertilizers and Other Commercial
Products. Anal. Chern., Vol. 20. pp. 1082-1084.
MacIntire, W. H., et ale Removal of Fluorides from Natural Waters by Calcium
Phosphate. Industrial and Engineering Chemistry, Vol. 30, No.2.
Nachod, F. C. and J. Schubert. 1956. Ion-Exchange Technology. Academic Press
Inc. NY.
National Lime Association. Chemical Lime Facts, Bulletin 214. Washington, D. C.
20005.
59
-------
Ockershausen, R. W. Disposal of Hydrofluoric Acid Wastes. Industrial Chemicals
Division. Allied Chemical Corporation.
Orion Research Incorporated. Analytical Methods Guide. Cambridge, Massachu-
setts. 3rd Ed. p. 8.
Orion Research Incorporated. Instruction Manual. Fluoride Ion Activity, Electrode
Model 94-09. Cambridge, Massachusetts.
Perry, John H. 1963. Chemical Engineer's Handbook: 4th Ed. Rohm and Haas
Technical Bulletin 1E-73-63. Helpful Hints in Ion-Exchange Technology.
Rohm and Haas Co., Amberlite Ion Exchange Resins Laboratory Guide. 1974.
Philadelphia, Pennsylvania.
Schippers, P. A. Test of Two Waste Products of Grumman Aerospace Corporation
as a Source of Nitrogen Fertilizer. Long Island Vegetable Research Farm of
Cornell University, Riverhead, N. Y.
Staebler, C. J. 1973. Treatment and Recovery of Fluoride Industrial Wastes. U. S.
Environmental Protection Agency #660/2-73-024.
Standard Methods for the Examination of Water and Wastewater. 1971. 13th Ed.
The Chemical Rubber Company. Handbook of Physics and Chemistry. 45th Ed.
p. B-147.
Vanderborgh, N. E. 1968. Evaluation of the Lanthanum Fluoride Membrane Elec-
trode Response in Acidic Solutions. Talanta, Vol. 15, pp. 1009-1013.
Warner, T. B. 1969. Lanthanum Fluoride Electrode Response in Water and 1M
Sodium Chloride. U. S. Government Research and Development Report 69(17)-68.
Naval Research Laboratory, Washington, D. C.
Zabban, W., and H. W. Jewett. 1967. The Treatment of Fluoride Wastes. Water
and Sewage Works. p. 415.
60
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APPENDIX A
PROCEDURE FOR ANALYSIS OF FLUORIDE
The total fluoride concentration in various samples was determined with an
Orion F- Specific Ion Electrode using the Orion-recommended, known addition pro-
cedure. Preliminary sample preparation varied depending on the concentration of
fluoride and other ions in the samples.
The following procedure was used:
1. Distill the sample to prevent precipitation after addition of sodium citrate
buffer.
2. Prepare a buffered sample solution based on the approximate fluoride con-
centration in the sample.
a. For fluoride concentrations less than 10 ppm, add 10 ml of saturated
sodium citrate to a 90-ml sample and adjust the pHto 8.
b. For high fluoride concentrations, mix an aliquot of the sample with satu-
rated sodium citrate to give a fluoride concentration of about 100 ppm.
Adjust the pH to 9.5-10.
3. Measure the electrode potential of 100 ml of buffered sample using an Orion
F- Specific Ion Electrode.
4. Add 10 ml of a standard solution (about ten times the anticipated concentra-
tion of the sample) and then measure the electrode potential.
5. Determine ".:1 E, " the difference between the initial potential (buffered
sample) and the final potential (with standard solution added).
6. Using the known addition table on Page 8 of the Orion Research Analytical
Methods Guide, determine "Q" corresponding to ".:1E. "
7. Calculate the concentration of the original sample by multiplying "Q" times
the concentration of the standardizing solution.
61
-------
APPENDIX B
PROCEDURE FOR ANALYSIS OF NITRATE IN CALCIUM NITRATE
The nitrate content in calcium nitrate was determined by an oxidimetric pro-
cedure (1) which involved reduction of nitrate to nitrite by excess ferrous ion and
measurement of the remaining ferrous ion by back titration with potassium dichro-
mate.
The following procedure was used:
1. Weigh out an amolIDt of sample such that 25 m1 of the solution contains
25-80 mg of nitrate.
2. Dissolve the sample in water and filter if the solution is turbid.
3. Transfer 25.00 m1 of the solution to an Erlenmeyer flask.
4. Add 25.00 ml of O. 2N ferrous sulfate solution and 20 m1 of concentrated
(6-8 molar) sulfuric acid.
5. Boil the solution for 3 minutes to complete reaction.
6. Prepare a blank containing 25.00 m1 of 0.2N ferrous sulfate solution and
20 ml of concentrated (6-8 molar) sulfuric acid to run at the same time.
7. Titrate the cooled solution with O. IN potassium dichromate using ferroin as
an indicator. Average error has been determined to be :1:0.2 percent.
(1)
Leithe, W. 1948. Oxidimetric Nitrate Analysis of Fertilizers and Other Com-
mercial Products. Anal. Chern., Vol. 20, pp. 1082-1084.
62
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APPENDIX C
PROCEDURE FOR ANALYSIS OF NITRATE IN WATER SAMPLES
The nitrate content in water samples was determined by the EP A automated
cadmium reduction method using a Teclmicon Autoanalyzer. The nitrates are reduced
to nitrites with a cadmium-copper catalyst and then reacted with sulfanilamide to form
the diazo compound. This is coupled in an acid solution (2.0 - 2.5 pH) with N-l-
naphthylethylenediamine hydrochloride. The azo dye intensity, which is proportional
to the nitrate concentration, is then measured with a colorimeter having a 540- II m
filter. .
The following procedure was used:
1. Set up the manifold (Figure 29). Note that the reductant column should be
in a 20-degree incline position with copper at the lower end.
2. Allow both the colorimeter and recorder to warm up for 30 minutes. Run a
baseline with all reagents, feeding distilled water through the sample line.
Adjust the dark current and operative opening on the colorimeter to obtain
a stable baseline.
3. Place appropriate nitrate standards in order of decreasing nitrogen concen-
tration. Complete loading of sample tray with unknown samples.
4. Switch sample line to sampler and start analysis.
5. Compute concentration of samples by comparing peak heights with standard
curve.
63
-------
0')
ff:>.
1
!
j
~
1L_--.-
SAMPLER 2
TO SAMPLE WASH
ml/min
0
4 0 0.42
WASTE
HO BLUE BLUE 1.60 H20
C-3* MIXER
R R 0.80 AIR
G G 2.00 H20
0.42 COLOR REAGENT
o 0
WASTE G G 2.00
WASTE
COLOR~~[~ p~
50mm TUBULAR flc ~ J
540mm FILTERS
Cd-Cu
DO
COLUMN**
,~
r=-
'0
Figure 29.
t:lLUt: I' I,VV 01-\IviPLE ~
y 'I.?O 8.5% NH4CL ::
y 1.20 AIR
i >:jj
~'=-=J
I
I
n
,
$f
g
I
.<~
PROPORTIONi~,jG PUMP
RECORDER
*FROM C-3 TO SAMPLE LINE USE
,030 x .048 POL YETHLENE TUBING.
"*SEE FIGURE 1. FOR DETAIL. COLUMN
SHOULD BE IN 20° INCLINE POSITION
WITH eu AT LOWER EI\JD.
Nitrate-nitrite manifold,
-------
APPENDIX D
TEST OF TWO WASTE PRODUCTS OF GRUMMAN AEROSPACE CORPORATION
AS A SOURCE OF NITROGEN FERTILIZER
P. A. Schippers
Long Island Vegetable Research Farm
(Cornell University)
Riverhead, N. Y. 11901
Products:
1.
Nitric- HF, descale fertilizer, 17.4% nitrogen (in this report called Descale).
2.
7 -17 deox fertilizer, 13. 6% nitrogen (further called Deox).
Comparison:
The test products were compared with Certified A. C. S. calcium nitrate
(Ca(N03)2 . 4H20) obtained from Fisher Scientific Company, Fair Lawn, New Jersey
07410 (Catalog C 109, Lot 743725) with the following impurities:
ppm
Insoluble matter and NH40H
Barium (Ba)
40
30
Chloride (CI)
20
Heavy metals (as Pb)
1
Iron (Fe)
1
Magnesium and Alkalies (as 8(4)
Sulfate (804)
1500
20
65
-------
Crop: Lettuce.
Varieties: 1. Iceberg (Hart's Seeds), crisp, heading type.
2. Parris Island (Harris Seeds), Cos or Romaine type.
3. Buttercrunch (Harris Seeds), Bibb type.
4. Salad Bowl (Harris Seeds), looseleaf, non-heading type.
Growing system:
Hydroponics: for part of the growing season without any rooting medium, for
later part of the season with Perlite* (super-coarse grade) as medium; in glasshouse.
Description of the Experiment:
Sowing: On October 27, 1975, seeds were sown in either Kys-kube** growing blocks
or in a bed of horticultural Perlite of propagating grade. The blocks and the bed
were flushed once a day for one hour with nutrient solution of 0.25 of the normal
strength from October 27 until November 3, 1975, O. 50 of the normal strength from
November 4 until November 7, and 0.75 of the normal strength from November 8
until November 24, 1975. After transplanting on November 24, the full strength was
given.
Growing: On November 24, plants growing in the Perlite bed were transplanted into
5.7cm (2.25 in) peat pots filled with Perlite of propagating grade. The pots were
slashed with a Imife at the bottom corners to facilitate the uptake of nutrient
solution and to give the roots a better opportunity to grow out of the pot into the
nutrient solution.
The plants in Kys-kubes and peat pots were placed in 3-m-Iong plastic roof
gutters through which nutrient solution flowed continuously. Two plants of each
variety in the Kys-kubes and two plants in peat pots were placed in each of four
gutters and the gutters were supplied with nutrient solutions either at normal strength
or at 1. 5 times the normal strength.
The nitrogen was supplied either in the form of Descale or in the form of the
pure calcium nitrate from Fisher.
On December 11, two more gutters which had been used for a different experi-
ment were prepared for the Deox fertilizer. Plants for these gutters were taken
from the corresponding Descale gutters. After that date, the setup was as follows:
*Perlite is heated and expanded volcanic rock. It has no buffering capacity and does
not contain any nutrients for the plant. Plant roots may extract some sodium and
aluminum.
**Kys-kubes are growing blocks, 5.1 cm (2 in) high and 5.1 cm X 5.1 cm (2 in X
2 in) at the base, consisting of a blend of organic and inorganic materials with
starter fertilizer.
66
-------
Concentration
of nutrients Form of
Gutter in solution calcium nitrate
1 1 Deox
2 1. 5x Deox
3 1x Laboratory chemical
4 1x Descale
5 1. 5x Descale
6 1.5x Laboratory chemical
The eight plants in each gutter were placed at 30-cm distances: one plant of
each variety in Kys-kubes, the other in peat pots with Perlite.
Nutrient solutions: The macro nutrients were supplied by KH2P04, MgS04. 7H20,
K2S04, all as pure laboratory chemicals, and calcium nitrate either in the form of
the laboratory chemical Ca(N03)2'4H20 or in the form of Descale or Deox. KOH was
used to adjust the pH to approximately 6.5.
The following micro-nutrients were given, also as pure laboratory chemicals
(except for the iron):
Fe:
10 ppm as Sequestrene
Mn:
0.47 ppm as H3B03
0.02 ppm as CuS04 . 5H20
0.65 ppm as MnS04 . H20
0.05 ppm as Na2Mo04 .2H20
0.12 ppm as ZnS04. H20.
B:
Cu:
Mo:
Zn:
The composition of the nutrient solutions in parts per million was:
Gutter Gutter
1, 3, 4 2, 5, 6
(Normal) (1. 5 x Normal)
K+ 280 420
++ 180 270
Ca
Mg++ 50 75
67
-------
Gutter Gutter
1, 3, 4 2, 5, 6
(Normal) (1. 5 x Normal)
NO; (N) 120 180
H2P04 30 45
2- 160 240
004
The total volume of nutrient solution in each gutter (including catch basin and
supply tank) was 10 I before and 25 I after adding Perlite to the gutters. The
Perlite was added after the first harvest on January 12, 1976, .in order to prevent the
plants from falling over, since they became too top-heavy for the size of the Kys-
kubes and peat pots and the roots had nothing to hold onto.
The old solutions were replaced by fresh ones every three weeks.
Temperature: Night temperature was maintained at 150C (590F) until December 12,
1975, and then increased to 200C (680F). Day temperature was maintained at 200C
(680F) until the same date, then increased to 250C (77oF), but on smmy days, day
temperatures could go as high as 300C (86oF).
Notes on the growth of the plants: Since the intensity of natural daylight is at a
minimum during the time of the year .in which the experiment was started, not too
much was expected of the growth of the crop. However, although growth was slow at
first, it picked up considerably during the later part of the growing period.
Some varieties were clearly more suitable for this type of growing than others.
The Iceberg lettuce did not head well, grew slowly and confirmed its reputation of
not being suitable for greenhouse growing. The Salad Bowl variety grew well, but for
some unknown reason started to bolt quite soon, a phenomenon which did not occur in
other experiments. For these reasons, and also to obtain some interim data, these
two varieties were harvested much earlier than the others which grew well.
The plants grown in the Kys-kubes grew far better than those grown in peat pots
with Perlite.
There was neither any visible differences in the growth of the plants grown with
the experimental fertilizers and those grown in the pure chemical, nor between the
plants which had received nutrient solutions of normal strength and those which had
received the stronger solutions.
Harvest:
On January 12, 1976, the heads of Iceberg and Salad Bowl were harvestedEd
weighed. Each head was cut into small pieces and dried in an oven at 700C (158 F)
for 16 hours, weighed again, ground in a Wiley mill and stored for future chemical
determinations. The same procedure was applied on February 3, 1976, with Parris
68
-------
Island and Buttercrunch varieties, with the only difference that only half or quarter
plants were dried. This was done because of their size. The heads were cut from
bottom to top, making sure that all tissues were represented proportionally.
Results:
The results (Table D-l) were statistically analyzed by analysis of variance
to show the responses of the plants and the significance of the results.
Although there were some significant interactions between some of the vari-
ables, the source of nitrogen was not involved in any of these interactions with the
exception of the interaction between source of nitrogen and variety and between
source of nitrogen and concentration. Therefore, a discussion of these interactions
will be omitted except for the two mentioned above.
Yield: For the purpose of this report the only interest would be in whether or not the
source of nitrogen had a significant effect on yield. According to the analysis of
variance it had not, meaning that results with both Descale and Deox were indisguish-
able from those obtained with the pure chemical.
Percentage dry matter: Also in this case the source of nitrogen had no sta-
tistically significant influence.
Percentage nitrogen in the dry matter: Again, the source of nitrogen had no
influence, but the concentration of the fertilizer in the nutrient solution affected the.
nitrogen content of the dry matter. An increase in fertilizer concentration. resulted
in a higher nitrogen content, a result which was expected.
The two interactions mentioned before were at the 5% probability level. The
one between source of nitrogen and variety meant that not all varieties reacted in ex-
actly the same way to the source of nitrogen. The variety Salad Bowl, for instance,
had the highest nitrogen concentration (4.57%) with the pure chemical and the lowest
(3.88%) with the Deox, whereas the variety Buttercrunch reacted in reverse (4.04 and
4.25%).
The interaction between source of nitrogen and concentration of the nutrient
solution meant that the differences in nitrogen content caused by the concentration
were smaller if the plants had grown in Descale or Deox than if they had been grown
in the pure chemical. These differences in reaction, however, were of little practi-
cal value.
Nitrogen uptake per plant: The source of nitrogen was of no significance.
Conclusion:
No distinction could be made in growth of the plants, in yields of fresh material,
in N-uptake by the plants, in dry matter content of the plants or N-content of the dry
matter between plants grown in either of the experimental solutions or in the pure
laboratory chemical.
69
-------
TABLE D-l. AVERAGE RESPONSE OF LETTUCE TO VARIOUS TREATMENTS
Yield of Nitrogen in Nitrogen Uptake
Source of Fresh Material, Dry Matter, Dry Matter, per Plant
Variation g/plant % % mg
Variety
Iceberg 37 a 5.54 a 3.97 a 83 a
Parris Island 345 b 5.42 a 4.01 a 747 b
Buttercrunch 258c 4.93b 4.15 a 531 c
Salad Bowl 108 d 5.24 a 4.35 b 243d
-;J Nitrogen source
0
Pure chemical 195 5.13 4.15 401
Descale 172 ns 5.29 ns 4.11 ns 360 ns
Deox 195 5.42 4.10 443
Concentration
1 x normal 186 5.20 3.96 a 384
1.5 x normal 188 ns 5.36 ns 4.27 b 419 ns
Substrate
Kys-kubes 223 a 5.24 4.26a 485 a
Peat pots 152 b 5.32 ns 3.98 b 320 b
ns: Differences are not statistically significant.
a,b,C,d: Differences between treatments followed by different letters within each group are statistically significant; differences between those
followed by the same letters are not.
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TECHNICAL REPORT DATA
(Please read Inslructions on the reverse before completing)
1. REPORT NO. 12. 3. RECIPIENT'S ACCESSION-NO.
EPA-600/2-78-048
4. TITLE AND SUBTITLE 6. REPORT DATE
Treatment and Recovery of Fluoride and Nitrate March 1978 issuing date
Industrial Wastes: Phase II 6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S) 8. PERFORMING ORGANIZATION REPORT NO.
Christian J. Staebler, Jr.
9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT NO.
Grumman Aerospace Corporation lBB610
Bethpage, New York 11714 11. CONTRACT/GRANT NO.
s800680
12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED
Industrial Environmental Research Laboratory, Cin., OR Final
Office of Research and Development 14. SPONSORING AGENCY CODE
U.S. Environmental Protection Agency 600/12
Cincinnati, Ohio 45268
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Laboratory and pilot-scale techniques to treat selected metal-finishing solu-
tions and rinse waters containing fluorides and nitrates were developed and success-
fully demonstrated. Lime-treat~ent parameters were optimized for various fluoride
and nitrate influent levels. Ion-exchange techniques reduced the fluoride and ni-
trate concentrations of rinse waters to three and ten parts per million, respective-
ly. Pilot-scale centrifugal techniques to separate precipitated calcium fluoride and
metal hydroxide sludges were developed. The nitrate concentration of centrifuged
effluents was reduced from 28,000 to less than five parts per million by passing the
effluents through a thin-film, mechanically aided evaporator. Fluoride concentration
was reduced from 117,000 to less than one part per million. The potential feasibil-
ity of using calcium fluoride sludge as a strength-maintaining additive for concrete
was shown. Greenhouse tests indicated that concentrated calcium nitrate recovered
from mechanically aided evaporation is a beneficial and practical plant fertilizer.
Economic and production scale-up plans for process solution and rinse water treat-
ment are also presented.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS b.IDENTIFIERS/OPEN ENDED TERMS COSA TI Field/Group
Chemical Processing, solutions
Industrial waste treatment; and rinse waters, Fluoride and l3B
Calcium fluroides; Byproducts nitrate removal, Calcium
nitrate fertilizer, Lime treat-
ment, Precipitation, Cemtrofiga
separation, Ion exchange,
Mechanically aided evaporation
18. DISTRIBUTION STATEMENT 19. SECURITY CLASS (This Report) . NO. OF PAGES
Unclassified I 82
Release to public 20. SECURITY CLASS (This page) '. PRICE
Unclassified
EPA Form 2220.1 (9.73)
71
«U.S. GOVERNMENT PRINTING OFFICE: 1978- "~~~~;~2
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