Development Document for Effluent Limitations Guidelines
and New Source Performance Standards for the
CANE SUGAR REFINING
Segment of the
Sugar Processing
Point Source Category
MARCH 1974
U.S. ENVIRONMENTAL PROTECTION AGENCY
Washington, D.C. 20460
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-a.
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DEVELOPMENT DOCUMENT
for
EFFLUENT LIMITATIONS GUIDELINES
and
NEW SOURCE PERFORMANCE STANDARDS
CANE SUGAR REFINING SEGMENT
OF THE
SUGAR PROCESSING INDUSTRY
Russell E. Train
Administrator
Roger Strelow
Acting Assistant Administrator for
A1r and Water Programs
Allen Cywln
Director, Effluent Guidelines Division
Robert W. Dellinger
Project Officer
March, 1974
Effluent Guidelines Division
Office of Air and Water Programs
U. S. Environmental Protection Agency
Washington, D. C. 20460
For sale by the Superintendent of Documents, U.S. Government Printing Offic*
Washington, B.C. 20102 - Price $2.10
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ABSTRACT
This document presents the findings of an extensive study of the cane
sugar refining industry for the purpose of recommending Effluent Limita-
tions Guidelines, Federal Standards of Performance, and Pretreatment
Standards for the Industry for the purpose of implementing Sections 30U,
306, and 307 of the "Act."
Effluent Limitations Guidelines contained herein set forth the degree of
effluent reduction attainable through the application of the Best
Practicable control Technology Currently Available (BPCTCA) and the
degree of effluent reduction attainable through the application of the
Best Available Technology Economically Achievable (BATEA) which must be
achieved by existing point sources by July 1, 1977, and July 1, 1983,
respectively. The Standards of Performance for new sources (NSPS) con-
tained herein set forth the degree of effluent reduction which is
achievable through the application of the Best Available Demonstrated
Control Technology, Processes, Operating Methods, or other alternatives.
The cane sugar refining segment of the sugar processing industry has
been divided into two subcategories: liquid cane sugar refining and
crystalline cane sugar refining. The proposed limitations for all three
levels of technology as set forth above establish the requirements for
discharge to navigable waters (see Table 1).
Supportive data and 'rationale for development of the Effluent
Limitations Guidelines and Standards of Performance are contained in
this document. The remaining segments of the sugar processing industry
not contained within this report are raw cane sugar processing and beet
sugar processing. Raw cane sugar processing is being studied at this
time and is to be presented at a later date. Beet sugar processing has
been previously studied and is the subject of a separate report entitled
- Beet Sugar Processing Segment of the Sugar Processing Industry.
iii
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TABLE OF CONTENTS
SECTION PAGE
I CONCLUSIONS 1
II RECOMMENDATIONS 3
III INTRODUCTION 9
Purpose and Authority 9
Summary of Methods 9
Background of the Cane Sugar Industry 12
Definition of the Industry 12
Process Description 16
IV INDUSTRY CATEGORIZATION - 35
V WATER USE AND WASTE CHARACTERIZATION 39
Specific Water Uses 39
Waste Water Characteristics 53
VI POLLUTANT PARAMETERS 67
Major Waste Water Control Parameters 67
Additional Parameters 70
VII CONTROL AND TREATMENT TECHNOLOGY 77
In-plant Control Measures 77
Waste Treatment Technology 82
Treatment & Control Technology
Currently Employed 96
VIII COST, ENERGY, AND NON-WATER QUALITY
ASPECTS 103
The Model Refineries 103
Assumptions Pertaining to Water
Usage, Raw Waste Loadings, and
Alternatives of Control and
Treatment 103
Assumptions Pertaining to the Cost
of Control and Treatment Alternatives 107
Basis of Cost Analysis 108
Crystalline Refining 109
Discharge of Process Waste Streams
to Municipal Treatment Systems 127
Liquid Refining 128
Discharge of Process Waste Streams
to Municipal Treatment Systems 138
Related Energy Requirements of
Alternative Treatment and Control
Technologies 140
Non-Water Quality Aspects of
Alternative Treatment and Control
Technologies 141
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TABLE OF CONTENTS (Cont'd)
SECTION PAGE
IX EFFLUENT REDUCTION ATTAINABLE THROUGH
THE APPLICATION OF THE BEST PRACTICABLE
CONTROL TECHNOLOGY CURRENTLY AVAILABLE
- EFFLUENT LIMITATIONS GUIDELINES 145
Introduction 145
Effluent Reduction Attainable Through
the Application of Best Practicable
Control Technology Current Available
for the Cane Sugar Refining Industry 146
X EFFLUENT REDUCTION ATTAINABLE THROUGH THE
APPLICATION OF THE BEST AVAILABLE
TECHNOLOGY ECONOMICALLY ACHIEVABLE -
EFFLUENT LIMITATIONS GUIDELINES 151
Introduction 151
Effluent Reduction Attainable
Through the Application of the
Best Available Technology
Economically Achievable - Effluent
Limitations Guidelines for the
Cane Sugar Refining Processing
Industry 152
XI NEW SOURCE PERFORMANCE STANDARDS 157
Introduction 157
New Source Performance Standards for
the Cane Sugar Refining Processing
Industry 157
XII ACKNOWLEDGEMENTS 159
XIII REFERENCES 161
XIV GLOSSARY 165
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FIGURES
NUMBER TITLE PAGE
1 American Cane Sugar Refineries 13
2 Sucrose 17
3 Simplified Process Diagram for Cane Sugar
Refining 18
4 Typical Bone Char Refinery 20
5 Typical Carbon Refinery 23
6 Triple-Effect Evaporation 27
7 Devices to Reduce Entrainment 29
8 Liquid Sugar Refining 32
9 Waste Water Flow Diagram for a Liquid Sugar
Refinery 40
10 Waste Water Flow Diagram for a Crystalline
Sugar Refinery 41
11 Water Balance in a Liquid Sugar Refinery 44
12 Water Balance in a Crystalline Sugar Refinery 45
13 Process Water Discharge Versus Size for Crys-
talline Cane Sugar Refining 52
14 Raw Waste Loadings and Water Usage for the
Average Crystalline Cane Sugar Refinery 64
15 Raw Waste Loadings and Water Usage for the
Average Liquid Cane Sugar Refinery 65
vn
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FIGURES
( CONTINUED )
NUMBER TITLE PAGE
16 Entrainment Reduction 80
17 Filter Cake Recycle System 83
18 Raw Waste Loadings and Water Usage for the
Model Crystalline Cane Sugar Refinery 104
19 Raw Waste Loadings and Water Usage for the
Model Liquid Cane Sugar Refinery 105
20 Condenser Water Loadings and Water Usage for
Crystalline Cane Sugar Refineries 106
21 Condenser Water Loadings and Water Usage for
Liquid Cane Sugar Refineries 106
22 Schematic of Activated Sludge System 112
viii
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TABLES
NUMBER TITLE PAGE
1 Recommended Effluent Limitations and Standards
of Performance 3
2 Sources of Data 11
3 American Gane Sugar Refineries 14
4 Multiple Ownership of Sugar Refineries 16
5 Unit Water Intake and Waste Water Discharges 42
6 Decolor1zat1on Media Used by Each Cane Sugar
Refinery Currently 1n Operation 47
7 Summary of Types of Decolor1zat1on Media Used
by Cane Sugar Refiners 48
8 Process Water Discharge For Crystalline Cane
Sugar Refining ( All Refineries ) 50
9 Process Water Discharge for Crystalline Cane
Sugar Refining ( Average of the Best ) 51
10 Condenser Water Summary: Loadings 55
11 Condenser Water Summary: Concentrations 56
12 Char Wash Summary: Loadings 58
13 Char Wash Summary: Concentrations 58
14 Waste Water Characteristics of Liquid Sugar
Refineries 60
15 Total Waste Loading Summary 61
16 Total Flow Summary 62
1x
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TABLES
( CONTINUED )
NUMBER TITLE PAGE
17 Summary of Waste Water Treatment and Disposal
Techniques of United States Cane Sugar Refineries 98
18 Summary of Waste Loads from Treatment Alternatives
for the Selected Crystalline Refineries 116
19 Summary of Alternative Costs for a 545 Metric
Tons per Day Crystalline Sugar Refinery 117
20 Summary of Alternative Costs for a 1900 Metric
Tons per Day Crystalline Sugar Refinery 118
21 Implementation Schedules for a Small Crystalline
Sugar Refinery 119
22 Implementation Schedules for a Large Crystalline
Sugar Refinery 123
23 Summary of Waste Loads from Treatment Alternatives
for the Selected Liquid Refinery 132
24 Summary of Alternative Costs for a 508 Metric
Tons per Day Liquid Sugar Refinery 133
25 Implementation Schedules for a Liquid Sugar
Refinery 134
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SECTION I
CONCLUSIONS
For the purpose of developing Effluent Limitations Guidelines and New
Source Performance Standards, the cane sugar refining segment of the
sugar processing industry has been divided into two subcategories: (1)
liquid cane sugar refining, and (2) crystalline cane sugar refining.
The main criterea for subcategorization of the cane sugar refining
segment include differences in the manufacturing process employed which
result in different waste water loadings.
Factors such as age and size of facilities, nature of water supply, raw
material quality, and process variation were considered and found to
further substantiate the subcategorization as stated.
It was determined that three refineries are currently achieving no dis-
charge of pollutants to navigable waters by means of land retention.
Two refineries discharge all process wastes to municipal treatment
systems, and ten other refineries discharge all wastes except barometric
condenser cooling water to municipal systems. The majority of the
remaining fourteen refineries partially treat their wastes.
It is estimated that the total industry cost of achieving the Best
Practicable Control Technology Currently Available (BPCTCA) and the Best
Available Technology Economically Achievable (BATEA) are $5,910,000 and
$15,000,000 respectively.
The remainder of the cane sugar processing industry, namely the raw cane
sugar processing segment, will be studied in a separate effort and a
report is to be presented at a later date.
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SECTION II
RECOMMENDATIONS
It is recommended that the following effluent limitations be applied as
the Best Practicable Control Technology Currently Available (BPCTCA)
which must be achieved by existing point sources by July 1, 1977; the
Best Available Technology Economically Achievable (BATEA) which must be
achieved by existing point sources by July 1, 1983; and the Standards of
Performance for new sources (NSPS):
TABLE 1
RECOMMENDED EFFLUENT LIMITATIONS GUIDELINES AND
STANDARDS OF PERFORMANCE
BPCTCA - Crystalline Cane Sugar Refining
Subcategory
(a) Any crystalline cane sugar refinery discharging both barometric
condenser cooling water and other process waters should be required to
meet the following limitations. The BOD5 limitation is determined by
the addition of the net BOD5, attributed to the barometric condenser
cooling water to that amount of BOD5 attributed to the treated process
water. The TSS limitation is that amount of TSS attributed to the
treated process water. Where the barometric condenser cooling water and
process water streams are mixed and impossible to measure separately
prior to discharge, the values should be considered net.
Effluent
Characteristic
Maximum for
any one day
Effluent
Limitations
Average of daily
values for thirty
consecutive days
shall not exceed
BODS
TSS*""
pH
BOD5
TSS"
PH
(Metric units) fccr/kkg of melt &o*ys
?MC - iz» «?#;t 1.19 0.43-^
£.->;- 30 ,, ^ 0.27-/5a 0.09- ^?"^:
Within the range 6.0 to 9.0.
(English units) Ib/ton of melt
2.38 0.86
0.54 0.18
Within the range 6.0 to 9.0.
—-««
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TABLE 1
RECOMMENDED EFFLUENT LIMITATIONS GUIDELINES AND
STANDARDS OF PERFORMANCE
(Continued)
(b) Any crystalline cane sugar refinery discharging barometric
condenser cooling water only should be required to achieve the following
net limitations:
Effluent
Characteristic
Maximum for
any one day
Effluent
Limitations
Average of daily
values for thirty
consecutive days
shall not exceed
BODS
BODS
(Metric units) Jcg/kkq of melt
(English units) Ib/ton of melt
2.04 0.68
BATEA - Crystalline Cane Sugar Refining
Subcategory
Effluent
Characteristic
Maximum for
any one day
Effluent
Limitations
Average of daily
values for thirty
consecutive days
shall not exceed
BOD5
TSS
pH
BODS
TSS~
pH
(Metric units) kg/kkg of melt M if
O.ia^ToSJT? 0.09*¥ ~"
0.11 '- £0 *j« 0.035 ' '•? ~ » Jf
Within the range 6.0 to 9.0.
(English units) Ib/ton of melt
0.36 0.18
0.21 0.07
Within the range 6.0 to 9.0.
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TABLE 1
RECOMMENDED EFFLUENT LIMITATIONS GUIDELINES AND
STANDARDS OF PERFORMANCE
(Continued)
NSPS ->• crystalline Cane Sugar Refining
Subcategory
Effluent
Characteristic
Maximum for
any one day
Effluent
Limitations
Average of daily
values for thirty
consecutive days
shall not exceed
BOD5
TSS
PH
BOD5
TSS
pH
(Metric units)
kg/kkg of melt
0.18 0.09
0.11 0.035
Within the range 6.0 to 9.0.
(English units) Ib/ton of melt
0.36 0.18
0.21 0.07
Within the range 6.0 to 9.0.
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TABLE I
RECOMMENDED EFFLUENT LIMITATIONS GUIDELINES AND
STANDARDS OF PERFORMANCE
(Continued)
BPCTCA - Liquid Cane Sugar Refining
Subcategory
(a) Any liquid cane sugar refinery discharging both barometric
condenser cooling water and other process waters should be required to
meet the following limitations. The BOD5 limitation is determined by
the addition of the net BOD5 attributed to the barometric condenser
cooling water to that amount of BOD5 attributed to the treated process
water. The TSS limitation is that amount of TSS attributed to the
treated process water. Where the barometric condenser cooling water and
process water streams are mixed and impossible to measure separately
prior to discharge, the values should be considered net.
Effluent
Characteristic
Maximum for
anv one dav
BOD5
TSS
pH
BOD5
TSS
pH
(Metric units)
Ce»,J = 30
Effluent
Limitations
Average of daily
values for thirty
consecutive days
shall not exceed
of melt , f^fffL ;
0.78 0.32' '•''
0.50 -3«rf ^ijt 0.17 - ;o<&
Within the range 6.0 to 9.0
(English units) Ib/ton of
1.56 0.63
0.99 0.33
Within the range 6.0 to 9.0
•3.0
68
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TABLE 1
RECOMMENDED EFFLUENT LIMITATIONS GUIDELINES AND
STANDARDS OF PERFORMANCE
(Continued)
(b) Any liquid cane sugar refinery discharging barometric condenser
cooling water only should be required to meet the following net
limitations:
Effluent Effluent
Characteristic Limitations
Average of daily
values for thirty
Maximum for consecutive days
any one day shall not exceed
(Metric units) kg/kkg of melt ,„
BODS 0.45 : 33^7 0.15 - ?" ^M
(English units) Ib/ton of melt
BODS 0.90 0.30
BATEA - Liquid Cane Sugar Refining
Subcategory
Effluent Effluent
Characteristic Limitations
Average of daily
values for thirty
Maximum for consecutive days
any one day shall not exceed
(Metric units) Jcg/kkg of melt f -^
BODS 0.30*"* "U& 0.15r'*- "*
TSS 0.09 * W*.^^ 0.03 - s^"j *J
pH Within the range 6.0 to 9.0.
(English units) lb/ton..of melt
BODS 0.60 0.30
TSS 0.18 0.06
pH Within the range 6.0 to 9.0.
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TABLE 1
RECOMMENDED EFFLUENT LIMITATIONS GUIDELINES AND
STANDARDS OF PERFORMANCE
(Continued)
NSPS - Liquid Cane Sugar Refining
Subcategory
Effluent
Characteristic
Maximum for
anv one day
Effluent
Limitations
Average of daily
values for thirty
consecutive days
shall not exceed
(Metric units) kg/kkg of melt
BOD5 0.30 0.15
TSS 0.09 0.03
pH within the range 6.0 to 9.0.
(English units) Ib/ton of melt
BOD5 0.60 0.30
TSS 0.18 0.06
pH Within the range 6.0 to 9.0.
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SECTION III
INTRODUCTION
PURPOSE AND AUTHORITY
Section 301(b) of the Act requires the achievement by not later than
July 1, 1977, of effluent limitations for point sources, other than pub-
licly owned treatment works, which are based on the application of the
best practicable control technology currently available as defined by
the Administrator pursuant to Section 304(b) of the Act. Section 301
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General information was obtained on all plants and detailed information was
collected for 28 (97X) of the 29 domestic cane sugar refineries identified
as currently in operation (see Table 2). The sources and types of infor-
mation consisted of:
a) Applications to the Corps of Engineers for Permits to Dis-
charge under the Refuse Act Permit Program (RAPP) which were
obtained for 2U refineries provided data on the charac-
teristics of intake and effluent waters, water usages, waste-
water -treatment and control practices employed, daily pro-
duction and raw materials used.
b) A questionnaire previously submitted to segments of the in-
dustry (17 refineries) by the United states Cane Sugar Re-
finers1 Association.
c) On-site inspections of 19 refineries which provided infor-
mation on process diagrams and related water usage, water
management practices, and control and treatment practices.
d) A sampling of four refineries to verify the accumulated
data.
e) other sources of information including personal and telephone
interviews and meetings with regional EPA personnel, industry
personnel, and consultants; State Permit Applications; inter-
nal data supplied by industry; and a review and evaluation
of the available literature.
The reviews, analyses, and evaluations were coordinated and applied to the
following:
a) An identification of distinguishing features that could po-
tentially provide a basis for subcategorization of the in-
dustry. These features included raw material quality, age
and size of the refinery, nature of water supply, process
employed, and others, discussed in detail in Section IV
of this report.
b) A determination of the water usage and waste water character-
istics for each subcategory, discussed in Section V, including
the volume of water used, the sources of pollution in the plant,
and the type and quantity of constituents in the waste waters.
c) An identification of those waste water constituents, discussed
in Section VI, which are characteristic of the industry and
were determined to be pollutants subject to effluent limi-
tations guidelines and standards of performance.
d) An identification of the control and treatment technologies
presently employed or capable of being employed by the re-
10
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TABLE 2
SOURCE OF DATA
Refinery
Location
Size-kkg/day
(Average Melt) Visit Sample Data
Amstar C Baltimore, Md.
Amstar C Boston, Mass.
Amstar C Brooklyn, N.Y.
Amstar C Chalmette, La.
Amstar C Philadelphia, Pa.
J. Aron C Supreme, La.
C&H C Aiea, Hawaii
C&H C Crockett, Ca.
Colonial C Gramercy, La.
Evercane C Clewiston, Fla.
Glades County C Moore Haven, Fla.
Godchaux C Reserve, La.
Guanica C Ensenada, P.R.
Igualdad C Mayaguez, P.R.
Bnperial C Sugarland, Texas
Mercedita C Ponce, P.R.
National C Philadelphia
Revere C Charlestown, Mass.
Roig C Yabucoa, P.R.
Savannah Foods C Port Vfentworth, Ga.
South Coast C Mathews, La.
Southdown C Hbuma, La.
CPC C-L Yonkers, N.Y.
SuCrest C-L Brooklyn, N.Y.
Florida Sugar L Belle Glade, Fla.
Industrial L St. Louis, Mo.
Pepsico L Long Island, N.Y.
Ponce Candy L Ponce, P.R.
SuCrest L Chicago, 111.
C — Crystalline Refinery
L — Liquid Refinery
C-L — Combination Crystalline-Liquid Refinery
1 Corps of Engineers Application
2 Prior Analyses
3 Interview of ^Plant Personnel
4 Questionnaire
5 Verification Sattpling
2350
900
1900
2800
1900
680
170
3175
1350
360
420
1540
200
630
1350
545
1900
1090
360
1700
635
635
1650
750
350
275
725
55
775
No
Yes
Yes
No
No
No
No
Yes
No
Yes
No
No
Yes
No
Yes
Yes
No
Yes
Yes
Yes
No
Yes
NO
Yes
Yes
Yes
Yes
Yes
Yes
No
No
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Yes
No
Nb
No
No
NO
No
Yes
Nb
Yes
1,2,4
1,2,3,4
1,2,3,4,5
1,2,4
1,2,4
1,4
1,4
1,3,4
1,4
3
3
—
1,3
1
1,2,3,4
1,3
1,3,4
3
1,3
1,2,3,4,5
1,4
1,2,3,4
1,2,3,4
1,2,3
1,3,4
1,3,4
1,3,5
1,3
3,5
n
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fining industry, discussed in section VII, including the ef-
fluent level attainable and associated treatment efficiency
related to each technology.
e) An evaluation of the cost associated with the application of
each control and treatment technology, discussed in Section
VIII.
The results of this analysis indicated that three refineries are
currently achieving no discharge of pollutants to navigable waters by
means of land retention, two refineries discharge all process wastes to
municipal treatment systems, and ten other refineries discharge all
wastes except barometric condenser cooling water to municipal systems.
The majority of the remaining fourteen refineries partially treat or
partially retain waste waters.
BACKGROUND OF THE CANE SUGAR INDUSTRY
The earliest recorded production of sugarcane was in Southeast Asia
three thousand years ago. Sugarcane was introduced into Europe in the
eleventh century, and by the thirteenth century the crystallization of
sugar from cane juice was being practiced throughout the Eastern
Hemisphere.
The origin of sugarcane in the Western World was with the second voyage
of Columbus in 1U93. Commercial cane sugar production began in the
United States in the late eighteenth and early nineteenth centuries.
The growth of the industry experienced considerable instability until
the Federal Sugar Act of 1936 (amended in 1971) provided protective
tariffs, a quota system, and price control.
DEFINITION OF THE INDUSTRY
Cane sugar refineries produce either a white crystalline or a clear
liquid sugar from unrefined raw sugar which is purchased from domestic
or foreign factories. Molasses is produced as a by-product and is sold
as animal feed, for the making of alcohol, as a source of certain
organic chemicals (ethyl and butyl alcoholols, and acetic and citric
acids), and for other uses.
Due to the fact that raw sugar is more economically transported than is
refined sugar (raw sugar is not considered to be a foodstuff and thus
can be shipped in bulk without extensive sanitary safeguards),
refineries are generally located in urbanized retail market areas as
shown in Figure 1 and Table 3. The refinery located in Aiea, Hawaii,
produces sugar primarily for island consumption. The refinery at
Crockett, California, services the West Coast market and receives its
raw material primarily from the Hawaiian sugar factories.
In some cases, refineries can be located near both factories and retail
markets as can be observed in south Florida, New Orleans, and Hawaii.
12
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CRVSTALLINE SUGAR REFINERIES
LIQUID SUGAR REFINERIES
LIQUID AND CRYSTALLINE REFINERIES- •
REFINERIES OPERATING WITH SUGAR FACTORIES—6
HONOLULU
I S__L_A N__D_S OF
H A W A I I
& 29
FIGURE 1
AMERICAN CANE
SUGAR REFINERIES
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Refinery
TABLE 3
AMERICAN CANE SUGAR REFINERIES
Normal Melt
.Location _ kkg/dayj Map No.
[Crystalline Refineries (
Amstar
Amstar
Amstar
Amstar
Amstar
California & Hawaiian
California S Hawaiian
Colonial (Borden)
Evercane (savannah Foods)
Godchaux
Imperial
National
Revere
Savannah Foods
[Liquid Sugar Refineries
Florida Sugar (Borden)
Industr ia 1 (Bcrden)
pepsico
Ponce Candy
SuCrest
i»n
Baltimore, Md.
Boston, Mass.
Brooklyn, N.Y,
Chalmette, La.
Philadelphia , Penn .
Crockett, Calif.
Aiea, Hawaii
Gramercy, La.
Clewiston, Fla,
Reserve, La.
Sugarland, Texas
Philadelphia, Penn.
Charlestown, Mass.
Port wentworth, Ga.
(5) ]
Belle Glade, Fla,
St. Louis, Mo.
Long Island, N.Y.
Ponce, P.R.
Chicago, 111.
2350
900
1900
2800
1900
3175
170
1350
360
1540
1350
1900
1090
1700
350
275
725
55
775
6
1
24
15
»
25
19
12
26
8
11
5
27
18
17
10
2
29
9
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TABLE 3 (Continued)
Refinery
AMERICAN CANE SUGAR REFINERIES
Location
[Liquid-Crystalline Refineries (2)]
CPC ' Yonkers, N.Y.
Sucrest Brooklyn, N.Y.
[Refineries Operating with Sugar Factories (8)
Glades County
Guanica
Igualdad
J. Aron & Company
Mercedita
Roig
South Coast
Southdown
Moore Haven, Fla.
Ensenada, P.R.
Mayaguez, P.R.
Supreme, La.
Ponce, P.R.
Yabucoa, P.R.
Mathews. La.
Houma, La.
1650
750
420
200
630
680
545
360
635
635
3
7
16
21
20
13
22
23
14
28
-------
The refineries in Puerto Rico^ all of which operate in conjunction with
raw sugar factories, serve the Puerto Rican domestic market.
The 24 refineries in the continental United States and Hawaii are owned
by fifteen private corporations or cooperatives. Four of the refineries
in Puerto Rico are operated by the Puerto Rican government. Those
organizations operating.more than one refinery are listed in Table 4.
TABLE 4
MULTIPLE OWNERSHIP Of SUGAR REFINERIES
Owner
H eadquarters
Number of
Refineries
Amstar
California & Hawaiian
Borden
Savannah Foods
SuCrest
New York, N.Y.
San Francisco, California
Columbus, Ohio
Savannah, Georgia
New York, New York
PROCESS DESCRIPTION - CANE SUGAR REFINERIES
The raw material for cane sugar refining is the raw, crystalline sugar
produced by the cane sugar factories. Raw sugar consists primarily of
crystals of sucrose (CJ^H220J_1) with small percentages of dextrose
(glucose) and levulose (fructose), both with formulas of (C6HV2Q6) , as
shown in Figure 2, and various impurities which may include bagasse
particles, organics, inorganic salts, and microorganisms. Raw sugar
crystals contain a film of molasses, the thickness of which varies with
the purity of sugar, and in which the non-sucrose components are con-
centrated, . . , .
The raw sugar processed-by the American refineries may be of domestic or
foreign origin, and the production as well as the importation of raw
sugar is closely governed by U.S.D.A. quota. From a refining process
viewpoint, there is little difference in raw sugar related to its source
other than the amount of impurities present.
A cane sugar refinery receives raw sugar in bulk form by truck, rail,
barge, and/or ship, and stores it for periods up to several months in
large warehouses. As required by the refining process, the raw sugar is
conveyed from storage through continuous weighing to the magma mingler,
the first step in sugar refining. Figure .3 presents a simplified
process diagram of cane sugar refining.
16
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CHOH
H / fl
\
OH \ OH
HOCH
-0 C.
.0-
C CH2OH
H
i-
OH
OH
GLUCOSE
FRUCTOSE
FIGURE 2 -.-•:••--•
SUCROSE OR a-D-GLUCOP.YRANOSYL—M-FRUCTPFU'RANOSIDE
17
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Raw Sugar
Hot Water
AFFINATION
CENTRIFUGALS
MELTER
Mingling Syrup
FILTRATION
Scum and
Cake Disposal
Cake .
Disposal
Final
*
Molasses
CLARIFICATION
PRESSURE
FILTRATION
i
1
DECOLORIZATION
1
'
EVAPORATION
'
p
VACUUM PANS
CENTRIFUSATION
'
>
GRANULATION
FIGURE 3
SIMPLIFIED PROCESS DIAGRAM FOR CANE SUGAR REFINING
18
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Sugar refining may be broadly defined as the removal of most of the
molasses film and associated impurities from the surface of the raw
sugar crystals. The crystalline raw sugar is washed to remove part of
the molasses film, then placed into solution, taken through various
purification steps, and finally recrystallized. While the process is
simple in scope, a detailed discussion could fill many volumes. This
discussion will be necessarily of a limited nature. Furthermore,
processes may vary in detail considerably from refinery to refinery,
particularly in decolorization methods where the media may be bone char,
granular activated carbon, powdered activated carbon, vegetable carbon,
ion-exchange or other materials. The predominate media in the United
States, however, is bone char. Figure 4 presents a process flow diagram
of bone char refining and Figure 5 is a schematic of carbon refining.
Affination and Melting
The first step in the refining process is affination which begins with
mingling, or placing the raw crystals into a syrup solution. The main
source of the mingling syrup is the affination centrifugals. Either the
recycled syrup is heated in order to aid in loosening the molasses film,
or the resulting magma is heated in a revolving mixer. The magma is fed
into centrifugals, which separate the syrup and molasses from the sugar.
Hot water is then added to provide a washing action. The washed sugar
is discharged into a melter which also contains about one-half of the
sugar's weight in water. High-test sweet waters and remelt syrups may
also be added. Steam heat and mechanical mixing are supplied to the
melter. Melt liquor leaves the melter at a constant density of about
65° Brix and a temperature of about 66° centigrade (150° Fahrenheit).
The liquor is subjected to coarse screening and, in many cases, fine
screening to remove coarse materials such as sand and scale. These
relatively small amounts of impurities are normally discarded as solid
waste,
clarification (Defecation)
The screened melt liquor still contains fine suspended and colloidal
matter which are removed in clarification. Clarification may involve
coagulation and either flotation clarifiers or pressure filtration. The
most common chemical defecants are phosphoric acid, carbon dioxide, and
lime. The result of this treatment is neutralization of organic acids
and formation of a tri-calcium phosphate precipitate which entrains much
of the colloidal and other suspended matter in the liquor. Carbonation
produces a calcium carbonate precipitate. Inert filter aids, most
commonly diatomaceous earth, may be used alone or in conjunction with
phosphoric acid.
Clarification systems that remove the colloidal and suspended
precipitate by air flotation are called frothing clarifiers and are
based simply on the principle of rising air bubbles trapping the
precipitate and forming a scum on the liquid surface. Pressure
19
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Affination
Centrifugals
Sweet Water
Remelt from
Vacuum Pans
(from sheet 3)
->• To Vacuum Pans (sheet 3)
To Blow Up (sheet 2)
Acid
To Pressure
Filters
(sheet 2)
Primary
Clarifiers
FIGURE 4
TYPICAL BONE CHAR REFINERY
Clarifier Mud
to Secondary
'Clarification
(not shown) or
to mud filters
(sheet 2)
Sheet 1 of 3
2C
-------
Clarified
Sugar Liquor
(from sheet 1)
| j. Filter Aid
Hot Water —
Clarifier Mud
(from sheet 1}
I r Lime
Raw Affination
(from sheet 1)
I r—Filter
-*-*- Aid
Blow I
Ury
u
Steam
Product
Recycle
Low Test Wash
Water to Sewer
Filtered Sugar Liquor
to Evaporation or
Vacuum Pans (sheet 3)
Sweet water 4-
Filtered Sugar Liquor
Wash Water to
Sweet Water
Hot Third Syrup
Water (from sheet 3}
1 1
Char Cisterns
Spent Char
1
FIGURE 4 (CONTINUED)
TYPICAL BONE CHAR REFINERY
Sheet 2 of 3
21
-------
Char Filtered
Sugar Liquor
(from sheet 2)
Third Syrup
to Char Char
Filters Filtered
r- 73
m
CD
o -p.
m ,—*
o Q
CO
o
Sweet Water
Evaporation
•^—
s,
^Vac
X
^
To Liquid
Sugar Production
Welter
1
u
4
Centrifuge
i
r
V
Remelt to
Affination
(sheet 1)
Final
Molasses
-------
rv>
CO
RAW SUGAR STORAGE
AFFINATION
MELTING
CARBON FILTER
PRESSURE FILTER
CLARIFICATION
iUN LXUiANlaE
EVAPORATOR
VACUUM PANS
GRANULATOR
CENTRIFUGE
CRYSTALLIZATION
GRADED
GRANULATED
SUGAR
I
BULK SUGAR
LIQUID SUGAR PLANT
POWDERED
SUGAR
LIQUID SUGAR
FIGURE 5
TYPICAL CARBON REFINERY
-------
filtration commonly takes place in a cloth or leaf-type filter with cake
removal by means of high pressure sprays.
The mudsr scums, and filter muds produced in clarification contain sig-
nificant sugar concentrations which must be recovered. Frothing
clarifier scums, particularly tri-calcium phosphate scums, are often
sent to a second clarifier and the resulting scum is filtered on rotary
vacuum drums with the addition of filter aid. The press cake is usually
handled in a dry form and taken to landfill but may be slurried. High-
test sluicings may be dewatered in rotary vacuum filters and the
resulting sweetwater added to affination syrups and the dewatered cake
used as filter aid for filtration.
Decolorization
After affiliation and clarification, the sugar liquor still contains im-
purities and color that require physical adsorption for removal. As
previously stated, most large crystalline refineries use fixed bed bone
char cisterns (also called filters), although in more than 50 years
there have been no new refineries equipped with them. An individual
cistern is commonly three meters (ten feet) in diameter and six meters
(20 feet) deep and holds approximately 36 metric tons (40 tons) of bone
char and 20,800 liters (5,500 gallons) of sugar liquor. There are
generally 30 cisterns per million kilograms of daily melt.
Sugar liquor passes in parallel through each cistern in a downward
direction and undergoes adsorption of the color bodies and ions. From
90 to 99 percent of color is removed, with the higher removal occurring
at the beginning of the cycle. Divalent cations and anions and
polyvalent organic ions are effectively removed, as are phosphate and
bicarbonate. Monovalent ions are not removed.
After some period of operation, the decoloration ability of the char
decreases to an unacceptable level and the char must be washed and
regenerated by heat in kilns or char house furnaces. The sugar liquor
in the cistern is displaced with a piston effect by hot water. The
water effluent is a low purity sweet water and is taken to evaporation
for sugar recovery. The total amount of sweet water produced is usually
about one-half of the cistern's volume.
After the purity of the water effluent has degraded to a point where
further sugar recovery is considered uneconomical, it is released as a
waste water stream. The amount of wash water used may be governed
either by time or by ash content.
After the last of the wash water has drained from the char cistern, the
char is discharged from the cisterns, dried by hot air, and regenerated
in kilns. The kilns provide a temperature of about 550° Centigrade and
a controlled amount of air. Under these conditions any organic residue
is destroyed and the buffering and decolorizing capacity of the char is
renewed.
24
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The operation of a granular carbon refinery is in many ways similar to
that of a char refinery, but there are at the same time significant
differences. Granular carbon adsorbs minimal ash and produces
considerably more sweet water. The only waste water normally associated
with the decolorization step in the process is water used for
transporting the carbon. Transport water can be reused as transport
water, but must be discharged periodically due to bacterial growth.
Most granular carbon refineries discharge transport water once or twice
a week,
Powdered activated carbon is used for decolorization in small refineries
and in liquid sugar production. Regeneration of powdered carbon is
difficult and it is normally discarded after one or two cycles.
However, in 1972, one company announced the successful and economical
regeneration of powdered activated carbon.
The clarified liquor is contacted and agitated for about 15 to 20
minutes with a slurry of carbon prepared with water or sugar solution.
After that period of time, carbon will not adsorb more coloring matter,
but coloring matter already adsorbed can be washed back into the sugar
solution. The temperature of treatment is about 82° centigrade (180°
Fahrenheit). After the treatment is completed, about five kilograms (10
pounds) of filter aid per 3,800 liters (1,000 gallons) of sugar liquor
is admixed and thoroughly dispersed in the liquor before filtration.
The filtration is accomplished in filter aid precoat-type leaf filters.
The cycle of each filter unit varies from five to twenty four hours,
depending on the filterability and color of the sugar liquor that is
being filtered. The decolorized filtrate is checked in a precoat-type
leaf filter and then sent to the double-effect evaporators for
concentration prior to crystallization. The total filter aid
consumption is about O.U to 0.5 percent based on refined sugar output.
The filter cake containing the filter aid, carbon, and impurities is
sent in slurry form to the clarification scum tank, and all this mixture
is filtered in a dry discharge type pressure filter (either plate and
frame or leaf type); all solids are discarded, after sweetening off, in
dry cake or slurry form in a suitable disposal area.
Ion-exchange resins are used to a limited extent in sugar refining for
demineralization (deashing) or further color removal. They are used
most extensively in carbon and liquid sugar refineries. Refinery
liquors are percolated through a cation-exchanger which adsorbs alkaline
salts from the liquor and leaves it highly acidic. Then the liquor is
percolated through an anion-exchanger which removes the free acid and
converts the sugar liquor to a neutral state. This double percolation
can be avoided by using cationic and anionic resins mixed together in a
single-bed cistern. The operation of ion-exchange beds in refineries is
not unlike that of many industrial applications in that they are
regenerated in place with sodium chloride, sulfuric acid, or other
chemicals depending on the type of resin. The cost and disposal of
chemicals needed for regeneration of ion-exchangers has precluded its
application for the entire refining process.
25
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Evaporation
No matter what method of decolorization is used, the final steps of re-
crystallizing and granulating are essentially the same in all
refineries. The first step in recrystallization is the concentration of
the decolorized sugar liquor and sweet waters in continuous-type
evaporators.
An evaporator is a closed vessel heated by steam and placed under a
vacuum. The basic principle is that the juice enters the evaporator at
a temperature higher than its boiling temperature under the reduced
pressure, or is heated to that temperature. The result is flash
evaporation and the principle allows evaporators to be operated in a
series of several units. This practice is called multiple-effect
evaporation, with each evaporator being an "effect", and is illustrated
in Figure 6. In general, the vacuum in each effect is created by the
condensation of the vapors from that effect in the subsequent effect.
The heat of vaporization of the juice in each effect is supplied by the
vapors from the previous effect, with the exception of the first and
last effects. The first effect normally has live steam or exhaust steam
resulting from power production provided to it, and the last effect has
a vacuum caused by the condensation of its vapors in the condenser. The
temperature and pressure of each effect is, therefore, lower than the
preceding effect.
The cane sugar refining industry commonly uses double or triple-effect
evaporation with the short tube or calandria type of evaporator (as
illustrated) , although the Lillie film evaporator is used in some
installations.
Condensation of the last effect vapors may be provided by one of several
condenser designs, but all operate on the principle of relatively cold
water passing through a cylindrical vessel, contacting the hot vapors,
and condensing them. The resulting hot water leaves through a long
vertical pipe called a barometric leg. Air is removed from the system
by a vacuum pump or steam ejector. The condenser cooling water, or
barometric leg water, at a flow rate of perhaps 76,000 cubic meters per
day (20 million gallons) in a large refinery, is the largest volume of
water used in a cane sugar refinery. It is often untreated river or sea
water and is unsuitable for reuse in other processes in sugar refining
although some refineries use better quality water which is recycled
after cooling in a cooling tower or spray pond, and then reused in other
processes.
A problem common to the sugar refiner in his attempt to prevent sugar
loss and to the environmentalist in his attempt to prevent pollution is
the entrainment of sugar in the vapors from the evaporators and vacuum
pans. The condensed steam from the first effect has not come into
direct contact with the sugar solution and is essentially pure water.
It is usually used as feed water for the steam boilers as is the
condensate from the second effect. The condensates from the other
effects experience relatively little sugar entrainment and are used as
26
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D], Dg, D3, CONDENSATE VALVES
F], F2, F3, FEED VALVES
S? STEAM VALVE
VT, V2, V3, VENT VALVES
Ps> P]. Pg. PS> PRESSURES
TS» Tl» T2' T3» TEMPERATURES
FIGURE 6
TRIPLE EFFECT EVAPORATION
CONDENSER
-------
process water; however, in some cases "excess" condensate may be
discharged as a waste stream. The major problem, then, is with the
vapor from the last effect which tends to have greater entrainment than
the other effects. Due to its mixing with the condenser water, the
resultant volume is too large for reuse in the process. However, con-
denser water may be recirculated. If recirculated, the warm water from
the condensers of evaporators and vacuum pans is cooled in cooling
towers or spray ponds and recycled. Only a fraction of the volume goes
to the stabilization ponds as blowdown from the cooling tower or spray
pond. This volume is a function of the dissolved solids content of the
water being used as barometric condenser cooling water, one would not
recycle brackish water because of the high concentration of dissolved
solids. With good quality water, this blowdown can be less than one
percent.
Various methods of reducing entrainment are used in the industry, but
most are based on either the principle of centrifugal action or that of
direct impact; i.e., changing the direction of vapor flow so that liquid
droplets may veer away from the vapor, be impinged on a surface, and,
ultimately be returned to the liquid body, or allowing the vapor to come
into direct contact with a wet surface. Schematics of various methods
commonly used are shown in Figure 7.
The distance between the liquid level in the evaporator and the top of
the cylindrical portion of the body is called the vapor belt. This dis-
tance has a great effect on the degree of entrainment because the
further the vapor has to rise the greater the opportunity for liquid
droplets to fall out. Most evaporator vapor belts in refineries range
from 3.7 to 4.9 meters (12 to 16 feet) or about 2.0 to 2.5 times the
length of the tubes.
Refineries monitor sucrose concentrations in condensate and condenser
water in order to avoid sugar contamination in boiler feed waters and
sugar loss in condenser water. The frequency of monitoring may vary
from continuous (auto analyzers) to hourly, daily, or weekly. The
methods of analysis for sucrose most commonly used are the alphanaphthol
and resorcinol tests. Both methods are based on color change resulting
from the reaction of the test reagent with sucrose.
Crystallization
After concentration ,in evaporators, in the case of crystalline
refineries, the sugar liquor and sweet waters are crystallized in
single-effect, batch type evaporators called vacuum pans. Several pans
are used exclusively for commercial granulated sugar and the resulting
syrups are boiled in other pans,, as shown in Figure U. Calandria pans
are commonly used and are similar to the calandria evaporator described
above except that the pans have larger diameters and shorter tubes in
order to handle the more concentrated liquid.
In order for sugar crystals to grow in a vacuum pan, the sugar solution
must be supersaturated. There are three phases of supersaturation in
28
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(A) Zigzag Baffle
r.
(B) Catch All
(C) Cyclone Separator
{DJ'ln-Lfne- Baffle. Box
Demi'stef
FIGURE 7 --:/:;^-
DEVICES TO REDUCE ENTRAINMENT
29
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sugar boiling; the metastable phase in which existing crystals grow but
new crystals do not form, the intermediate phase in which existing
crystals grow and new crystals do form, and the labile phase in which
new crystals form spontaneously without the presence of others. The
formation of new or "false" crystals is undesirable and the pan must be
maintained in that narrow range of sucrose concentration and temperature
which provides the metastable phase and allows the growth of seed
crystals. Automatic controls such as level, pressure, and viscosity
instrumentation for pan operation are used extensively in sugar
refining. ;
Since vacuum pans are essentially single-effect evaporators, each pan
must have a vacuum source and a condenser, as described above for
evaporators. Sugar entrainment is a potential problem, particularly
during start-ups or upsets, and various catchalls, centrifugal
separators, or baffle arrangements are used along with sucrose
monitoring (see Figure 7). In some cases a small surface condenser is
inserted between the pan and the barometric condenser to act as a heat
exchanger in order to heat process water. This also serves to reduce
sucrose entrainment.
After the formation of crystals in the pans, the massecuite content of
the pan—called a strike—is discharged into a mixer where it is gently
agitated, and then into high speed centrifugals where the crystals are
separated from the syrup. The crystals remaining in the centrifugals
are washed with hot water to remove remaining syrup, and the crystalline
sugar is discharged and sent to a combined dryer-cooler or to a dryer
followed by a cooler.
There are normally four straight refinery massecuites boiled in the
vacuum pansi filtered and evaporated first liquor and three remelt
strikes derived from affination syrup, refinery run-off, soft sugar run-
offs, and excess sweet water. The first refinery strike is boiled from
first liquor, the second is boiled from first strike run-off, the third
refinery strike is boiled from second run-off and the fourth strike from
third run-off. The procedure of boiling second, third, and fourth
refinery massecuites is the same as for the first one. In a refinery
where only white sugar is produced, the last refinery strike run-off
(fourth) can be used in affination as a mingling syrup. Some refineries
use it to produce "soft sugars". It can be diluted and filtered through
bone char or granulated adsorbents, or treated with powdered activated
carbon and used again in boiling. The sugar recovered from the remelt
strikes is used for the production of additional refined sugar and well
exhausted refinery blackstrap molasses. From 10 to 15 percent of the
original solids in the melt are recycled through the remelt (or
recovery) stations.
Finishing
The dryer or granulator is usually a horizontal, rotating drum 1.5 to
2.U meters (five to eight feet) in diameter and 7.6 to 11 meters (25 to
35 feet) long which receives steam heated air along with the sugar
30
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crystals. It may consist of one or more drums in parallel. The granu-
lators remove most of the one percent moisture content to 0.02 percent
or less. In addition, the dryers serve to separate the crystals from
one another. After drying, the sugar goes to coolers, which are similar
drums without the heating elements.
Any lumps ; remaining in the sugar are then removed by fine screening.
Screening also accomplishes crystal size grading.
Both the granulating and screening processes produce considerable
amounts of dust. Wet dust collectors are commonly used to collect this
dust and the resulting sugar solution is collected as sweet water.
The finished crystalline sugar is transported to conditioning silos and
then ultimately to packaging or bulk shipment. In the larger granulated
sugar refineries it is not uncommon to produce liquid sugar by melting
granulated sugars and then decolorizing the solution with powdered
activated carbon; the resulting solution is then filtered and cooled
before being sent to storage as liquid sucrose. It may also be inverted
to either 100 percent, 50 percent or any other degree of inversion and
stored separately from liquid sucrose in stainless steel clad tanks
provided with ultra-violet lamps and air circulation filters for
sterilization purposes.
Liquid Sugar Production
As noted in Table 3, there are four refineries in the United states that
produce liquid sugar exclusively as a final product and two that produce
large portions of liquid as well as crystalline sugar. Most of the re-
maining twenty-two produce some liquid sugar by melting granulated
sugar.
As shown in Figure 8, the initial refining steps of affination, decolor-
ization, and even evaporation in a liquid sugar refinery are essentially
the same as in a crystalline sugar refinery. The primary difference
occurs in the fact that liquid sugar refineries do not recrystallize
their primary product. While this preempts the necessity of using
vacuum pans to effect crystal formation and growth in the case of the
primary product, nevertheless, all but two liquid refineries use vacuum
pans for the crystallization of remelt sugars, producing molasses as a
by-product. The two liquid refineries that do not remelt use a highly
pure raw material. The production of liquid sugar is essentially a
concentration and decolorization of the melted raw sugar solution.
Because crystal formation is not a part of primary liquid sugar
production, considerably less condenser water and process steam is
required. This results in substantially less water usage to process the
same quantity of raw cane sugar into liquid sugar than that required to
process it into crystalline sugar. This is further discussed in Section
V. After evaporation, the sugar solution is filtered and cooled and
then sent to storage as liquid sugar. It may also be inverted to a
specific degree and stored separately in stainless steel clad tanks
equipped with ultra-violet lamps and air circulation filters to insure
31
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Raw Sugar
AFFINATION
MELTING
Steam
Water
CLARIFICATION
FILTRATION
GRANULAR CARBON
ION EXCHANGE
Water
EVAPORATION
Carbon
I
FILTRATION
Diatomaceous Earth
INVERSION
Refined Sugar
FIGURE 8
LIQUID SUGAR REFINING
SWEET WATER
l
HOT WATER
32
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sterilization. The
as those used in the
crystalline sugar.
processes of filtration and inversion are the same
formulation of liquid sugar by the melting of
33
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-------
SECTION IV
INDUSTRY CATEGORIZATION
In the development of effluent limitation guidelines and standards of
performance for the cane sugar refining industry, it was necessary to
determine whether significant differences exist which form a basis for
subcategori zation o f the industry. The obj ective of industry
subcategorization is to subdivide the industry in order that separate
effluent limitations and standards be established for such
subcategories. Several factors were considered significant with regard
to identifying potential subcategories in the cane sugar refining
industry. These factors included:
1) Raw material quality
2) Refinery size
3) Refinery age
4) Nature of water supply
5) Land availability
6) Process variation
After consideration of the above factors, the cane sugar refining
industry has been divided into two subcategories: liquid cane sugar
refining and crystalline cane sugar refining. The justification for
this subcategorization is presented below.
Raw Material Quality
All cane sugar refineries process raw sugar as produced by raw sugar
factories. An obvious point of inquiry in this regard is the source of
raw sugar—namely, imported versus domestic raw sugar. A significant
portion of raw sugar refined in the United States is imported from
Africa, Latin America, the Phillipine Islands, and Southeast Asia.
Depending upon the operation of the factory, and to some extent upon the
conditions under which raw sugar is shipped and stored, raw sugar could
vary in impurity and moisture content. Investigations revealed that no
significant variation in raw sugar quality exists because of
specifications imposed by individual refineries.
The exceptions are two liquid refineries which impose higher than normal
standards for raw sugar purchases. One refinery purchases raw sugar
from selected Louisiana and Central America factories, while the other
purchases from selected Florida factories. The high quality of raw
sugar allows these two refineries to avoid remelting and preempts the
use of vacuum pans (as previously discussed in Section III,
Introduction) . Neither of these refineries discharges waste water
directly to^surface waters. One is located in an urban area and
discharges all waste to a municipal sewer; the other has a rural siting
and has geographical conditions which allow for total impoundage of all
waste waters.
35
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For the purpose of establishing national effluent limitations and
standards, these two refineries are considered to be exceptions to
general practices. They are therefore not applicable as examples of
best practicable or best available technologies because of the
nonavailability of this high^purity raw sugar to the refining industry
in general. For this reason, separate subcategorization based on raw
material quality is not required.
Refinery Size
As indicated in section III, cane sugar refineries vary considerably in
size. The smallest operation is the Ponce Candy refinery, with a
refining capacity of 55 metric tons (60 tons) per day. The California 6
Hawaiian refinery at Crockett, California, with a refining capacity of
3175 metric tons (3500 tons) per day, claims the distinction of being
the world's largest sugar refinery. Other large refineries are located
in the urbanized Northeast, in Savannah, Georgia, and in the New Orleans
area. The smaller refineries are generally those associated with sugar
factories.
It might be expected that larger refineries would have better operation
than smaller ones; however, in actual practice this is not always the
case. While data are more variable for small refineries, no evidence is
available which shows significant differences in process water usage
(See Section V) . For the above reasons size is not regarded as a
technical element for subcategorization. Size is considered to be a
factor to be further studied for possible economic impact; for this
reason, cost estimates for control and treatment pertaining to typical
large and small refineries are included in Section VIII, Cost, Energy.
and Non*-Water Quality Aspects.
Refinery Age
Cane sugar refineries vary considerably in age of structure; several of
the larger refineries currently operating were originally constructed in
the decades following the American Civil War, while others were con-
structed after the Second World War. On a basis of unit operations em-
ployed, all refineries have undergone a process of continuous moderniza-
tion. The age of the walls of a refinery is no indication of the age of
the processing equipment within the walls. No definitive subcategoriza-
tion on the basis of age can be established. This conclusion is further
substantiated in that one of the oldest refineries has been determined
to be exemplary in terms of inplant controls and practices and raw waste
characteristics.
36
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Nature of Water Supply
The quantity and quality of fresh water supplies utilized by refineries
were oriqinally considered to be possible elements for industry
subcategorization because of potential prohibitive factors that could be
encountered in control and treatment. Water used for process or boiler
water must be of highest quality; if a high quality source of water is
unavailable, a refinery must provide treatment. However, the quality of
water used as condenser cooling water is unimportant; it was observed to
vary from municipal water to sea water. Typically, refineries use a low
quality surface water as barometric condenser cooling water.
The major importance of the gross characteristics of condenser water is
that with a high quality intake, the discharge (which essentially has no
net pollution except for temperature and entrained sucrose) can be
reused in the refining process. Thus a major waste water stream,
condenser cooling water, can be significantly reduced or, depending on
the relative volumes, virtually eliminated. One refinery accomplishes
this by utilizing municipal water as the source for condenser cooling
water. It is a liquid refinery which does not use vacuum pans, for
reasons discussed above and in Section III, and thus has a relatively
low volume of condenser water. More typically, due to the volumes
required and based on present practices, refineries utilize available
surface waters as condenser cooling water, regardless of quality.
Land Availability
Land availability was originally considered as a possible element for
subcategorization because of the potential economic advantages and
technical feasibility of waste water treatment and retention by
lagooning, land disposal, and impoundage (see Section VII, Control and
Treatment Technology). Land availability has been defined as the
ownership or potential ownership of land, or the use or potential use of
land owned by others with the owner's permission, with such land being
of sufficient quantity to provide treatment of waste water by lagooning,
land disposal, or impoundage, and with the stipulation that the economic
value of the land does not prohibit its use in such manner. For a
number of large refineries in urban areas, the nonavailability of land
must further be defined as the lack of sufficient space for industrial
waste water treatment facilities. However, these refineries presently
have access to municipal treatment systems, to which -they discharge
their process waste water.
It was determined that relatively little of the sugar refining industry
has available land. Forty-five percent of the refinery installations
may be considered to be rurally located, but these represent only about
25 percent of the industry on a production basis. Land and excavation
costs for total impoundage of waste waters make this treatment
alternative prohibitive for the industry as a whole. The option exists,
however, with a proper choice of site location based on a careful
consideration of geographical and climatic conditions, for new sources
to utilize the availability of land in eliminating discharge to
37
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navigable waters. For the purpose of establishing uniform national
effluent limitations guidelines and standards land availability is not
regarded as a technical element necessitating subcategorization.
Process Variation
While the production of refined sugar from raw sugar involves similar
operational principles in any refinery, in practice considerable process
variation can occur. These variations may be caused by the end product
desired or by the attitude of refinery management.
The only process variation which produces significant differences with
regard to waste water generation is that which produces liquid versus
crystalline sugar (discussed previously in Section III). Due to the
reduced amount of recrystallization necessary in liquid refining,
crystalline refineries discharge almost twice as much water (on a unit
basis) as liquid refineries. In terms of BOD5 loading, liquid
refineries produce approximately two times as much BODj> (on a unit
basis) as crystalline refineries. This will be further discussed in
Section Vr Water Use and Waste Characterization.
Another process difference which has to be considered as a potential
element for subcategorization is the type of decolorization medium used
in the production of crystalline sugar—activated carbon versus bone
char. As is shown in Section V, no significant differences occur in
process water use as a result of utilization of bone char versus
activated carbon as the decolorization medium.
Because of significant differences in water usage and waste loadings the
cane sugar refining industry has been divided into two subcategories;
liquid cane sugar refining and crystalline cane sugar refining. Within
the liquid sugar subcategory there are four refineries which produce
exclusively liquid sugar and two refineries which produce liquid in
addition to crystalline sugar. These refineries account for over twenty
percent of total sugar production. The remainder of the twenty-nine
refineries produce crystalline sugar as their primary product.
38
-------
SECTION V
WATER USE AND WASTE CHARACTERIZATION
SPECIFIC WATER OSES - CAME SUGAR REFINERIES
Figure 9 shows a schematic diagram of water usage and waste water flows
in a typical liquid sugar refinery and Figure 10 presents one for a
typical crystalline refinery. The major in-plant water uses include:
Barometric condenser cooling water
Filter cake slurry
Char wash
Floor wash water
Carbon slurries
Boiler makeup
Truck and car wash
Affination water
Ion-exchange regeneration
Water use varies widely among cane sugar refineries due to variations in
process, water reuse, and conservation techniques. As shown in Table 5,
the amount of fresh water used in refineries varies from 10.5 to 64.2
cubic meters per metric ton (2,520 to 15,400 gallons per ton) of raw
sugar melted. The average water usage in liquid sugar refineries is
approximately 18.1 cubic meters per metric ton (4,350 gallons per ton),
while the average for crystalline refineries is appxoximately 38.2 cubic
meters per metric ton (9,160 gallons per ton). Combination
crystalline-liquid cane sugar refineries use approximately 35.2 cubic
meters per metric ton (8,450 gallons per ton).
Water balances for a liquid and a crystalline refinery are shown in
Figures 11 and 12, respectively. Negligible water enters a sugar
refinery from raw material. High quality fresh water enters the liquid
refinery illustrated at a rate of 1.67 cubic meters per metric ton of
raw sugar (400 gallons per ton) and is used for all process purposes
other than cooling water. Cooling water is used for the barometric
condensers at a rate of 20.9 cubic meters per metric ton (5,000 gallons
per ton) of raw sugar melted, and the source of this water is typically
the nearest body of surface water. Raw water in the crystalline
refinery shown is used at a rate of 45.1 cubic meters per metric ton
(10,800 gallons per ton) of raw sugar melted; 3.38 cubic meters (810
gallons) of this is high quality water used for various purposes while
41.7 cubic meters (10,000 gallons) is low quality surface water used as
barometric condenser cooling water.
In general, cane sugar refineries are more sophisticated in waste water
control techniques than are sugar factories (and more conscious of sugar
losses); however, current practices for water reuse are generally
limited to recovery of high purity sweetwaters for their sucrose content
and reuse of condensates for boiler feed water and other purposes.
39
-------
RAW SUGAR
WATER
FILTER AID
WATER
CARBON
WATER
REMELT SUGAR
STEAM
CRYSTALLIZER
— MOLASSES
CONDENSER COOLING WATER
CONDENSATE TO BOILER FEED OR OTHER USE
FLOOR
STEAM 1 WATER
WASH
L
TRUCK
WASH
EXCESS SHE
WATER
FLOTATION
CLARIFIERS
FILTRATION
TREATMENT
BACKWASH
FILTER FILTER CAKE
PRESS
»
SPENT CARBON
REGENERATION WASTE
CONDENSER COOLING
iHATER "
CARBON
COLUMN
EXCHANGE
EVAPORATIQN
REFINED LIQUID
SUGAR
CONDENSATE
TO BOILER
FEED OR
OTHER USE
WATER STEAM
TO SWEET WATER
FIGURE 9
WASTEWATER FLOW DIAGRAM FOR A LIQUID SUGAR REFINERY
40
-------
MOLASSES
FIGURE 10
WASTEWATER FLOW DIAGRAM FOR A CRYSTALLINE REFINERY
41
-------
TABLE 5
UNIT WATER* INTAKE AND WASTE WATER DISCHARGES
CANE SUGAR REFINERIES
Ref i nery
C-l
C-2
C-3
C-4
C-5
C-6
C-7
C-8
C-9
C-ll
C-12
C-14
L-l
L-2
L-3
L-4 .
Intake Discharge
48.5 48.5
16.8 16.8
42.9
44.6
45.2 43.8
42.4
25.8 25.8
64.2
38.1
25.0
63.1
3.322
10.5 10.5
16.0 16.0
16.0
30.0
Condenser
Water
44.9
16.1
43.2
42.5
40.6
24.4
62.8
34.1
24.4
61.71
23.5
8.0
16.0
14.1
26.9
Process
Water
3.6
0.7
1.4
1.3
1.8
1-4
1.4
4.0
0.6
1.4
2.7
1.9
3.1
Decolorization
Wash
0.66
0.54
0.84
0.22
* All values expressed as cubic meters per kkg of melt.
1 Based on pump capacity, not on actual measured flows.
2 Has a recycle system for barometric condenser cooling
water resulting in a reduction in water discharged.
42
-------
TABLE 5
( CONTINUED )
UNIT WATER* INTAKE AND WASTE WATER DISCHARGES
CANE SUGAR REFINERIES
Refinery Intake Discharge
CL-1 22.5
CL-2 47.9 47,9
CF-1
CF-2
CF-3
CF-4
Condenser
Water
21.3
47.1
91. 33
45.0
68. 65
72. 06
Process
Water
1.2
0.8
1.0
8.64
2.2
1.4
Decolorization
Wash
* All values expressed as cubic meters per kkg of melt.
3 Based on vacuum pan capacity, not on actual measured flows.
4 Includes substantial water usage as a result of factory operations
(i.e. continuous water spray of bagasse pile). Maximum discharge
as a result of refinery operation alone approximated at 3.0 m3/kkg
of melt.
5 Based on pump capacity, not on actual measured flows.
° Based on maximum barometric condenser capacity; a greater than 50%
overflow occurs over pumping capacity of 86.9 m^/kkg of melt making
43.5 m3/kkg of melt the upper limit of actual barometric condenser
cooling water flow.
43
-------
EVAPORATOR
CONDENSERS
10.45 nvVkkg
FILTER WASH
.313 m3/kkg
CARBON COLUMN
.0835 m3/kkg
DISCHARGE
20.9 m3/kkg
FILTER WATER
DISCHARGE
1.67 m3/kkg
VACUUM PAN
CONDENSER.
10.45 m3/kkg
ION EXCHANGE
1.25 nrVkkg
FLOOR WASH
,0209"m3/kkg
FIGURE 11
WATER BALANCE IN A LIQUID SUGAR REFINERY
44
-------
t
SURFACE WATER
(10.000) 41.7
Values in M3/kkg cf melt
Parenthetical values in gallons/ ton of nelt
EVAPORATOR CONDENSER
(3^3001 13.8
VACUUM PAN CONDENSER
17.9
(10,000)
SAND FILTER BACKWASH
(90) 0.38
CHAR WASH WATER
(2501 1.04
MISCELLANEOUS
(10) 0.04
(350)
TRUCK OR CAR WASH AND FLOOR
DRAIN (15) 0.06
VACUUM PAN WASHOUT
(45) 0.19
(60) 0.25
BOILER FEED WATER (SLOWDOWN)
(20) 0.08
(20) 0.08
COIL AND HEATER
(7) 0.03
MISCELLANEOUS COOLING
f373) 1.56
(380) 1 ?
FRESH WATER
(810) . 3,38
I TOTAL DISCHARGE I
(10,810) 45.1 |
•^••••M^MBIMMBiMi^HM
FIGURE 12
WATER BALANCE FOR A CRYSTALLINE SUGAR REFINERY
45
-------
Obviously, the factor most affecting total water usage is process
variation. As indicated above, crystalline refineries with their
requirements for large volumes of barometric condenser cooling water use
60 percent more raw water than liquid refineries. The extremes of this
situation may Jbe illustrated by Refinery L-l which employs no
recrystallization in its manufacture of liquid sugar as compared to
Refinery C-8 which produces strictly crystalline sugar. The crystalline
refinery in this case uses over 600 percent more raw water.
Of all factors affecting water use, one of the most influential is the
availability of land for disposal, or conversely, the cost of sewer sur-
charges. For example. Refineries C-l, c-2, C-4, C-5, C-9, and C-14 dis-
charge process wastes to municipal sewers and average 36.6 cubic meters
of water usage per metric ton (8,600 gallons per ton) of melt, while
Refinery C-3 which does not discharge to municipal sewers, averages 42,9
cubic meters per metric ton (10,300 gallons per ton)of melt. Refineries
L-l and L-4 employ very similar processes but the former discharges all
waste waters to municipal sewers, while the latter uses total
impoundage, The difference in water usage is a factor of one to three,
Char Wash
Forty-two percent of all refineries use bone char for decolorization,
and these refineries include all of the largest refineries. Tables 6
and 7 give a breakdown of the type of decolorization medium used by each
of the 29 refineries currently in operation. The waste water produced
by the washing of char is a major waste stream in bone char refineries.
The amount of water used for char washing appears to be more dependent
on the opinion of the operator than on any other factor. This is
dictated fay the fact that in almost all aspects, the use of bone char is
more art than science.
The unit flow of char wash water varies from about 0.22 to approximately
0.84 cubic meters per metric ton (53 to 200 gallons per ton) of raw
sugar melted. The typical flow would appear to be about 0.6 cubic
meters per metric ton (14ft gallons per ton).
Other Process Wastes
A non-char refinery, whether crystalline or liquid, uses granular or
powdered activated carbon and possibly a combination of carbon and ion-
exchange to effect color removal. The major process wastes in a carbon
refinery consist of carbon wash water (and in some cases carbon slurry),
and possibly ion-exchange regeneration. For liquid refineries, the
tota1 proc ess water discharge (total wa ste water di scharge 1es s
barometric condenser cooling water) averages approximately 2.5 cubic
meters per metric ton (600 gallons per ton) of raw sugar melted.
A major factor considered in the subcategorization of the cane sugar
refining segment is the potential difference in process water discharge
due to the use of activated carbon versus bone char as the
46
-------
TABLE 6
DECOLORIZATION MEDIA USED BY EACH CANE SUGAR
REFINERY CURRENTLY OPERATING
Decolonization Media
Refinery
C-l
C-2
C-3
C-4
C-5
C-6
C-7
C-8
C-9
C-10
C-ll
C-12
C-13
C-14
L-l
1-2
1-3
L-4
L-5
CL-1
CL-2
CF-1
CF-2
CF-3
CF-4
CF-5
CF-6
CF-7
CF-8
Bone
Char
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Activated
Carbon
X
X
X
X
X
X
X
Activated Carbon Bone Char, Carbon,
plus Ion-Exchange and Ion-Exchange
X
X
X
X
X.
X
X
X
47
-------
TABLE 7
SUMMARY OF TYPES OF DECOLORIZATION MEDIA
USED BY CANh SUGAR REFINERS
Decolorization Media
Refinery
Type
Crystalline
Liquid
Bone
Char
14
0
Activated
Carbon
7
0
Activated Carbon
plus Ion-Exchange
1
5
Bone Char, Carbon,
and Ion- Exchange
0
0
Crystalline-
Liquid
Total
14
48
-------
decolorization medium in the production of crystalline cane sugar. A
substantial difference in discharge flew would mean a substantial cost
difference associated with the treatment of this waste water stream.
The average process water discharge for all crystalline refineries is
1.86 cubic meters per metric ton (450 gallons per ton) of melt. The
average process water discharge for all crystalline refineries utilizing
bone char as the decolorization medium is 1.85 cubic meters per metric
ton (445 gallons per ton) of melt, while for those using activated
carbon is 1.90 cubic meters per metric ton (455 gallons per ton) of
melt. This amounts to a difference of 2.6% more process water
discharged by crystalline activated carbon refineries. The average
process water discharge by those crystalline refineries employing better
water conservation techniques is 1.18 cubic meters per metric ton (283
gallons per ton) of melt. The average process water discharge by those
crystalline bone char refineries employing better water conservation
techniques is 1.17 cubic meters per metric ton (280 gallons per ton) of
melt, while for those refineries employing better water conservation
techniques and using activated carbon is 1.20 cubic meters per metric
ton (288 gallons per ton) of melt. This amounts to a difference of 2.5%
more process water discharged by the crystalline activated carbon
refineries. (See Tables 8 and 9). It has been determined from this
analysis that no significant difference exists in the process water
discharge of crystalline bone char versus activated carbon refineries.
Another factor considered was the difference in process water discharge
versus size for crystalline cane sugar refineries. As shown in Figure
13, no correlation exists between process water discharge and size of
the refinery*
Miscellaneous Water Uses and Waste Streams
Water is used for a number of purposes in a cane sugar refinery in addi-
tion to those previously discussed. Fortunately, most of the waste
streams produced can be recovered as low purity sweet water. In a well
operated refinery essentially all floor drainage is recovered. Conden-
sates produced by the condensation of vapors in all but the last effect
of multiple-effect evaporators are used for boiler feed water and other
purposes in the refinery.
Sludges, scums, and filter cakes have in some past instances been slur-*-
ried and discharged to streams. Current practice is to either impound
these slurries after desweetening or to handle them dry and provide land
disposal.
Minor waste streams may include boiler blowdown, cooling tower blowdown,
water treatment sludges, and various wash waters. These are highly
variable and minor in individual volume, but may be significant in terms
of total pollution load, particularly in a poorly operated refinery.
49
-------
TABLE 8
PROCESS WATER DISCHARGE FOR CRYSTALLINE
CANE SUGAR REFINING ( ALL REFINERIES )
Type of Number in
Refinery Study
Crystalline ( All ) 15
Bone Char 11
Activated Carbon 4
Average Process
Water Discharge Range
( m^/kkg of melt ) ( m^/kkg of melt )
1.86 0.6 - 4.0
1.85 0.6 - 4.0
1.90 1.0 - 3.0
Difference = 1.90 - 1.85 = 2.6%
1.90
50
-------
TABLE 9
PROCESS WATER DISCHARGE FOR CRYSTALLINE
CANE SUGAR REFINING ( AVERAGE OF THE BEST )
Average Process
Type of Number in Water Discharge
Refinery Study ( nvVkkg of melt ) (
Crystalline
( Best ) 9 1.18
Bone Char 7 1.17
Activated Carbon 2 1.20
Difference = 1.20-1.17 = 2.5%
1.20
Range
nr/kkg of melt )
0.6 - 1.4
0.6 - 1.4
1.0 - 1.4
51
-------
Ul
ro
4.0
- 3.0
m
V)
W)
8
O
2.0
1.0
^^ Overall Average
Average of the Best
500
1000
1500 2000
Size (kkg of melt)
2500
3000
3500
Figure 13
PROCESS WATER DISCHARGE VERSUS SIZE FOR
CRYSTALLINE CANE SUGAR REFINING
-------
Barometric Condenser Cooling Water
The major waste water stream in any refinery, in terms of volume, is
barometric condenser cooling water produced by contact condensation of
vapors from the last effect of multiple-effect evaporators arid from
vacuum pans. The amount of condenser water used on a unit basis in a
refinery varies with the availability of water, the extent of automation
in the control of operations, and the thermodynamic relationship between
the intake water and the vapors to be condensed; i.e., the higher the
temperature of condenser water influent, the larger the volume of
cooling water required for vapor condensation.
From the most reliable of data available, the average once-through flow
of barometric condenser cooling water for refineries of all categories
is nearly 31.5 cubic meters per metric ton (7,550 gallons per ton) of
raw sugar melted. For liquid sugar refineries the average is nearer
16.3 cubic meters per metric ton (3,900 gallons per ton) of raw sugar
melted, while for crystalline refineries the average is nearly 36.5
cubic meters per metric ton (8,750 gallons per ton) of melt.
Recirculation of barometric condenser cooling water is practiced by
several refineries; this technique of reduction of the discharge waste
water stream is further discussed in Section VII, Control and Treatment
Technology. P
WASTE WATER CHARACTERISTICS—CANE SUGAR REFINERIES
The characteristics of the total waste water effluent from a cane sugar
refinery vary widely, depending upon the characteristics of the
individual waste stream as described below. However, the following
major total raw waste streams can be identified:
1. The waste water produced by a crystalline sugar refinery
using bone char for decolorization. The majority of
waste stream components are char wash water which
is a part of the process water stream, and barometric
condenser cooling water.
2. The waste water produced by a crystalline sugar refinery
using carbon for decolorization. The major waste streams
from this type of refinery are barometric condenser
cooling water and process water, including ion-exchange
regeneration solutions and carbon slurries,
3. The waste water produced by a liquid sugar refinery em-
ploying affination and remelt and, therefore, using
vacuum pans. The discharge from this refinery is simi-
lar to that from the carbon crystalline refinery except
that the flow of barometric condenser cooling water is less,
4. The waste waters produced by a liquid refinery which does
not use affination, does not remelt, and therefore, does
53
-------
5.
not use vacuum pans. The discharge from this refinery
is similar to the discharge from number three except that
the barometric condenser flow is less.
The waste waters produced by a refinery which produces
both liquid and crystalline sugar by separate processes.
The discharge is a combination of numbers two and three.
Barometric Condenser Cooling Water
Theoretically, barometric condenser cooling water should carry net
values of only two constituents—sucrose and heat. The sucrose is
obtained from entrainment in last-effect evaporators and vacuum pans and
heat is a result of heat-exchange between the barometric condenser
cooling water and vapors. In terms of waste water characteristics,
sucrose appears in barometric condenser cooling water as BOD!i, COD, and
dissolved solids. In practice, as indicated in Tables 10 and 11,
relatively small concentrations of other constituents appear. In some
cases these probably appear as a result of analytical error and in
other cases because of contamination of the condenser water by unknown
waste streams.
The chemical composition of barometric condenser cooling water from a
particular refinery is highly variable because of variable operational
parameters as well as factors in the design of evaporators and vacuum
pans. The characteristics are similar to those from a raw sugar factory
and do not significantly vary according to process differences. The
BODjj concentrations vary from U mg/1 to 39 mg/1 and the BOD£ loadings
from 0.07 to 1.8 kilograms per metric ton (0.13 to 3.6 pounds per ton)
of melt.
Tables 10 and 11 indicate that the volume of barometric condenser
cooling water from liquid refineries is less than that from crystalline;
however, the BOD5 concentrations are higher. It is estimated that the
average crystalline refinery discharges barometric condenser cooling
water with a BODji concentration of about 12 mg/1 and a flow of 36.5
cubic meters per metric ton (8,750 gallons per ton) of melt, while that
from a liquid refinery has a BOD5 concentration of approximately 19 mg/1
and a flow of 16.3 cubic meters per metric ton (3,900 gallons per ton).
The BODJi loadings for all refineries are generally between 0.15 and 1.0
kilograms per metric ton (0.3 and 2.0 pounds per ton) of melt.
Adsorbents
Commercial adsorbents play an important role in the sugar refining
process. While a large portion of the original impurities in the raw
sugar is removed during defecation and clarification, there are con-
siderable amounts of colloidal and dissolved impurities that yield only
to adsorbent action.
54
-------
TABLE 10
CONDENSER WATER SUMMARY: LOADINGS*
Ul
CJI
Melt Flow
Refinery Source kkg/day m3/kkg BOD5_ COD
TSS
DS NH3-N Kjel-N N03-N
C-l
C-2
C-4
C-5
C-8
C-9
C-ll
L-3
L-4
CL-1
CL-2
4
3
4
2
2
2
2
3
2
2
4
2,350
1,900
1,900
900
1,350
1,900
1,350
775
350
1,630
750
44.9
16.1
43.2
42.5
62.8
34.1
24.4
14.1
26.9
21.4
47.1
0.40
0.07
0.60
0.21
0.94
0.38
0.52
0.44
0.16
0.17
1.8
1.1
0.64
1.1
16.6
1.9
0.75
0.83
1.4
2.7
0.04
6.6
0.81 44.5 0.02 0.07
0.29 0.0
0.43 8.8 0.06 0.29
0.38
0.0
0.11 0.42 0.0 0.0
0.24
0.02
1.8
0.20 0.13
0.0
0.41 0.11
0.0
Data Source: 1) RAPP Data
2) USCSRA Data
3) ESE Data
4) Internal Data
*A11 values reported in kg/kkg of melt unless otherwise specified
-------
TABLE 11
CONDENSER WATER SUMMARY: CONCENTRATICNS*
01
Melt Flow
Refinery Source kkg/day m3/day BOD5 COD TSS
DS
Kjel-N N03-N TP
C-l
C-2
C-4
C-5
0-8
C-9
0-11
L-3
L-4
CL-1
CL-2
4
3
4
2
2
2
2
3
4
2
4
2,350
1,900
1,900
900
1,350
1,900
1,350
775
350
1,630
750
105,600
30,500
82,300
38,250
84,800
64,700
33,000
10,900
9,400
34,700
35,300
9
4
14
5
15
11
21
31
6
8
39
25
40
25
391
30
22
34
99
100
2
141
18 990
18
10 203
9
0
8 30
9
1
38
0.4 1.5 4.4 2.9
0 0
1.5 6.8 9.5 2.6
0.01 0 . 0
Data Source: 1) RAPP Data
2) USCSRA Data
3) ESE Data
4) Internal Data
* All values reported in mg/1 except where otherwise noted
-------
Impurities that are removed by adsorbents may be classified (2) into
three types: (1) colloidal material, (2) color-forming compounds, and
(3) inorganic constituents.
Although a large number of adsorbents could theoretically be used in
sugar refining, only a few are in current use. These include:
1) Bone char
2) Ion-exchange resins, mixed media
3) Ion-exchange resins, specific media
4) Granular activated carbon
5) Powdered activated carbon
Bone char is used in most of the larger sugar refineries in the United
States and accounts for approximately 69 percent of all American sugar
refining. Bone char is effective in the removal of both inorganic
materials (ash) and organic impurities (colorants), and the resulting
char wash waters have high concentrations of both ash and colorants.
Since the subsequent char kiln does not affect the ash content in the
char, and since ash buildup in the char leads to decreased char effi-
ciency, considerable attention is given by refiners to the char washing
operation. The basic philosophy is that it is better to use too much
water than not enough.
As mentioned in Section III, the first portion of the char wash water is
recycled for sucrose recovery. The limiting factors on the amount of
char wash recycled are; (1) Sucrose concentrations in the wash water
decrease with washing time and eventually reach the point where recovery
is impractical; and (2) Ash concentrations in the wash water increase as
the sucrose concentrations decrease.
The spent char wash waters have BOD5 concentrations ranging from 500 to
2,000 mg/1 and dissolved solids~concentrations ranging from 1,000 to
3,000 mg/1 (see Tables 12 and 13). The BODj> loading from bone char
washing is between 0.15 and 1.7 kilograms per metric ton (0.3 and 3.4
pounds per ton) of raw sugar melted.
Ion-exchange is an effective remover of color as well as ash and is
utilized as the decolorization medium in liquid and combination liquid-
crystalline refineries. The waste characteristics resulting from the
regeneration of an ion-exchange bed are greatly dependent on the
particular use of that bed. lon^exchange is often used in combination
with carbon columns, and in these cases the usual practice is to remove
organics with the carbon column and then use ion-exchange as a final
polishing to remove inorganics. The inorganics of concern include
anions as well as cations; for such removal, a "monobed" consisting of
both cationic and anionic exchangers is often used. The cation-
exchanger can also be used as a polishing step. Most of the organic
material found in the sugar liquor is anionic, so that a strongly acidic
anion-exchanger (cationic resin) can be used to remove color.
57
-------
01
00
TABLE 12
CHAR WASH WATER SUMMARY: LOADINGS*
Melt Flow
Refinery Source kkg/day mj/kkg BOD5_ COD TSS DS NH3-N Kjel-N N03-N TP
02
C-8
C-14
Data Source:
*A11 values
3 1,900
4 1,350
3 1,700
1) RAPP Data
2) USCSRA Data
reported in kg/kkg
0.66
0.84
0.22
3)
4)
except
0.79 1.27
1.65 2.21
0.17 0.45
ESE Data
Internal Data
where otherwise
TABLE 13
CHAR WASH WATER SUMMARY:
Melt
Refinery Source kkg/day
02
08
014
3 1,900
4 1,350
3 1,700
Flow
mVday
1,250
1,130
380
BOD5_ COD
1,200 1,930
1,960 2,630
750 2,040
0,03 1.90 0.01
0,05
0.01 0.37 0.0 0.0
noted
CCNCENTRATICNS*
TSS DS NH3-N Kjel-N NC^-N
46 2,880 9.8
57
59 1,690 2.02 12.2
0.0
0.0
rpp
0.15
0.89
Data Source: 1} RAPP Data 3) ESE Data
2) USCSRA. Data 4) Internal Data
*A11 values reported in rag/1 except where otherwise noted
-------
Regeneration of ion-exchange beds usually results in a higher volume of
non-recoverable water than those from carbon columns and bone char. If
the ion-exchange bed is used primarily as an organic color remover
rather than as a final polishing and inorganic remover, the wash waters
have higher concentrations of organic carbon and correspondingly higher
BOD5 concentrations. The BOD5 loading from a liquid refinery using
carbon columns for organic color removal as well as for inorganic
removal is approximately 2.9 kilograms per metric ton (5.8 pounds per
ton) of melt. No analyses from ion-exchange beds used only for
inorganic removal have been made, but it appears that the BODI5 loading
is higher than from bone char and granular carbon and considerably lower
than from ion-exchange used for organic carbon removal.
Granular carbon is strictly an organic carbon remover and is, therefore,
a color remover. The regeneration of granular carbon requires sweeten-
ing off with water and heating of the carbon to volatilize organic
material, thereby reactivating the surface. Most of the wash water
which results from sweetening off a carbon column can be recovered for
process because of its sucrose content. A certain amount of water is
usually wasted because of low purity. While very little information on
the characteristics of this water is available, samples were collected
from one liquid sugar refinery. In this refinery a flow of 0.08 cubic
meters per metric ton (19.2 gallons per ton) of melt was wasted and the
resulting BOD5 loading was approximately 0.1 kilograms per metric ton
(0.2 pounds per ton) of melt.
Miscellaneous Waste streams
In addition to the waste water resulting from barometric condensers and
adsorbent regeneration, there are a number of minor waste streams
generated in a cane sugar refinery. These include; floor washings,
filter washings, truck and car washings, and boiler blowdown.
The flows associated with these waste streams are highly variable and in
some cases can be eliminated by reducing the volume of water used. This
results in a waste stream of higher sucrose concentration which can be
recycled back into the process. Table 14 indicates characteristics of
some of the filter wash waters.
Tables 15 and 16 list waste water characteristics in terms of concen-
trations and loadings from crystalline, liquid, and combination
crystalline-liquid refineries. It is apparent that in terms of unit
organic loadings, liquid sugar refineries have higher loadings than do
crystalline refineries. This is apparently due to the high organic
levels produced in the waste waters resulting from ion-exchange re-
generation (all of the liquid sugar installations listed use ion-
exchange as an integral part of their process) and to the extent of
recrystallization and subsequent remelt practiced by these refineries.
An extreme example of this is Refinery L-l, which has the 'highest waste
loading of all refineries listed. It is important to note that this
refinery does not remelt sugar (i.e., produces no molasses) and some
59
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TABLE 14
WASTE WATER CHARACTERISTICS OF LIQUID SUGAR REFINERIES
Characteristic
BCD5, mg/1
COD, mg/1
TS, mg/1
DS, mg/1
TSS, mg/1
pH
NH3. -N, mg/1
KN, mg/1
N03_ -N, mg/1
TP, mg/1
Total Coliform
per 100 ml
Fecal Coliform
per 100 ml
Filter
Cake Slurry
735(3
2,120(3
3,880(3
1,430(3
2,360(3
6.3(3
0.32(3
12.2 (3
75.8 (3
Truck &
Car Wash
17,250(1,3
40,300(1,3
6,530(1,3
6,480(1,3
50(1,3
7.2(1,3
3.04(1,3
0.49(1,3
1,80(1
0.60(3
240(1
240(1
Boiler
Slowdown
0(1
0(1
2,110(1
2,020(1
90(1
5.7(1
0(1
0(1
0(1
2(3
0(1
0(1
(1 RAPP data
(2 USCSRA questionnaire
(3 Internal data
Figures 14 and 15 are illustrations of the estimated flow and loadings
for the process water and barometric condenser cooling water, and total
discharge streams for the average crystalline and liquid cane sugar
refineries, respectively.
60
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TABLE 15
TOTAL WASTE LOADING SUMMARY*
Melt Plow
Refinery Source kkg/day m3/kkg BOD5 COD
TSS
DS
NH3-N Kjel-N NO3-N , TP
C-l
0-2
C-3
C-4
C-5
C-6
C-7
C-8
0-9
C-ll
C-14
L-l
L-3
L-4
CL-1
CL-2
4
3
2
2
2
2
2
2
2
2
2
2
3
2
2
1
2,350
1,900
2,800
1,900
900
170
3,175
1,350
1,900
1,350
1,700
275
775
350
1,650
750
48.5
16.7
42.9
44.6
43.8
42.4
25.8
64.2
38.1
25.0
3.32
10.5
16.0
30.0
22.5
47.9
0.63
1.0
1.8
1.7
1.1
1.9
2.4
1.7
1.7
2.1
0.87
5.1
3.7
2.2
2.3
1.1
1.9
1.9
5.0
3.1
17.1
1.5
6.6
3.4
3.5
3.4
1.5
6.1
6.6
5.7
5.6
0.92 46.9 0.02 0.08
0.34 0.01
3.6
1.4
12.5
0.08
0.06
0.34
1.2
1.3
8.4
0.94 16.2 0.00 0.01
7.4
1.1 -
0.00 0.00
0.21 0.14
0.00
0.03
0.00 0.00
Data Source: 1) RAPP Data
2) USCSRA Data
3) ESE Data
4) Internal Data
*A11 value reported in kg/kkg of melt unless otherwise specified.
-------
TABIE 16
TCttAL FICW SUMMARY*
Melt Flow
Refinery Source kkg/day m3/day
BCD5 COD
TSS
DS NH3-N Kjel-N
TP
C-l
C-2
C-3
C-4
C-5
C-6
C-7
C-8
C-9
C-ll
C-14
L-l
L-3
L-4
CL-1
CL-2
4
3
2
2
2
2
2
2
2
2
3
2
3
2
2
1
2,350
1,900
2,800
1,900
900
170
3,175
1,350
1,900
1,350
1,700
275
775
350
1,650
750
114,000
31,900
120,000
84,800
39,400
7,200
82,000
86,700
72,300
33,800
5,650
2,900
12,400
10,500
37,200
35,900
13
60
43
39
24
46
92
26
45
85
263
487
230
72
104
22
39
115
116
70
391
36
255
53
91
136
460
579
415
190
247
19 966 0.46
20
85
30
286
2
1
9
46
397
796
59 1,014 0.03
247
51
0.0
1.66 4.33 2.80
0.60 0.00
0.51 1.61
0.02 0.0 0.0
Data Source; 1} RAPP Data
2) USCSPA Data
3) ESE Data
4) Internal Data
*A11 values reported in mg/1 except where otherwise noted
-------
impurities that would otherwise be contained in molasses must leave the
refinery in its waste water. This principle is true to a lesser extent
for other liquid and liquid-crystalline refineries that remelt to
varying degrees. Refinery L-3, for example, does not remelt sugar in
its primary product line but must recrystallize in a side product line
(refer to Figure 9) to effect recovery of additional sugar and molasses
by-product. This refinery still produces a BOD5 loading of 3.70
kilograms per metric ton (7.40 pounds per ton) of raw sugar melted. The
impact of ion-exchange on the BOD5 loading from a refinery is
illustrated by the fact that 77 percent*of the total BOD5 loading at the
latter refinery is due to ion-exchange regeneration waste water.
Figures 1U and 15 are illustrations of the estimated flow and loadings
for the process water and barometric condenser cooling water, and total
discharge streams for the average crystalline and liquid cane sugar
refineries, respectively.
63
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Barometric Condenser
Cooling Water
BOD5 0.44 kg/kkg
(0.88 Ib/ton)
'2
Flow:
36.5 m3/kkg
(8750 gal/ton)
Process Water
$10 BOD5 1.10 kg/kkg (2.20 Ib/ton)
II&0 TSS 2.17 kg/kkg (4.34 lb/ton|
Flow:
1.86m3/kkg
(450 gal/ton)
Flow:
38.4 m3/kkg
(9200 gal/ton)
Discharge
BOD5 1.54 kg/kkg (3.08 Ib/ton)
TSS 2.17 kg/kkg (4.34 Ib/ton)
Figure 14
RAW WASTE LOADINGS AND WATER USAGE FOR THE
AVERAGE CRYSTALLINE CANE SUGAR REFINERY
64
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Barometric Condenser
Cooling Water
BOD5 0.31 kg/kkg
{0.62 Ib/ton)
Flow:
16.3m3/kkg
(3900 gal/ton)
Process Water
BOD5 3.36 kg/kkg (6.72 Ib/ton)
TSS5.58 kg/kkg (11.16 Ib/ton)
Flow:
2.5 m3/kkg
(600 gal/ton)
Flow:
18.8 m3/kkg
(4500 gal/ton)
Discharge
BOD5 3.67 kg/kkg (7.34 Ib/ton)
TSS 5.58 kg/kkg (11.16 Ib/ton)
Figure 15
RAW WASTE LOADINGS AND WATER USAGE FOR THE
AVERAGE LIQUID CANE SUGAR REFINERY
65
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SECTION VI
SELECTION OF POLLUTANT PARAMETERS
Major waste water parameters of pollutional significance for the cane
sugar refining segment include BOD (5-day, 20° Centigrade), suspended
solids, and pH. Additional parameters of significance include COD,
temperature, sucrose, alkalinity, total coliforms, fecal coliforms,
total dissolved solids, and nutrients (forms of nitrogen and
phosphorus). On the basis of all evidence reviewed, there do not exist
any purely hazardous or toxic pollutants (e.g., heavy metals,
pesticides) in wastes discharged from cane sugar refineries.
When land disposal of waste water is practiced, contribution to ground
water pollution must be prevented. If deep-well injection is used, all
practices must be in accordance with the Environmental Protection
Agency's "Policy on Subsurface Emplacement of Fluids by Well Injection"
with accompanying "Recommended Data Requirements for Environmental
Evaluation of Subsurface Emplacement of Fluids by Well Injection"(5).
MAJOg WASTE WATER CONTROL PARAMETERS
The following selected parameters are determined to be the most
important characteristics of cane sugar refining wastes. Data collected
during the preparation of this document was limited in most cases to
these parameters. Nevertheless, the use of these parameters adequately
describes the waste water characteristics of the refining industry. BOD
(5-day), suspended solids, and pH are the parameters selected for
effluent limitations guidelines and standards of performance for new
sources.
Biochemical. Oxygen Demand (5-day BOD)
Biochemical oxygen demand (BOD) is a measure of the oxygen consuming
capabilities of organic matter. For this reason1, in waste water
treatment, it is commonly used as a measure of treatment efficiency.
The BOD does not in itself cause direct harm to a water system, but the
matter which it measures may exert an indirect effect by depressing the
oxygen content of the water. Sewage and other organic effluents during
their processes of decomposition exert a BOD, which can have a
catastrophic effect on the ecosystem by depleting the oxygen supply.
Conditions are reached frequently where all of the oxygen is used and
the continuing decay process causes the production of noxious gases such
as hydrogen sulfide and methane, water with a. high BOD indicates the
presence of decomposing organic matter and subsequent high bacterial
counts that degrade its quality and potential uses.
Dissolved oxygen (DO) is a water quality constituent that, in
appropriate concentrations, is essential not only to keep organisms
living but also to sustain species reproduction, v4gor, and the
67
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development of populations. Organisms undergo stress at reduced DO
concentrations that make them less competitive and able to sustain their
species within the aquatic environment. For example, reduced DO
concentrations have been shown to interfere with fish population through
delayed hatching of eggs, reduced size and vigor of embryos, production
of deformities in young, interference with food digestion, acceleration
of blood clotting, decreased tolerance to certain toxicants, reduced
food efficiency and growth rate, and reduced maximum sustained swimming
speed. Fish food organisms are likewise affected adversely by
conditions of suppressed DO. Since all aerobic aquatic organisms need a
certain amount of oxygen, the consequences of total lack of dissolved
oxygen due to a high BOD can kill all inhabitants of the affected area.
If a high BOD is present, the quality of the water is usually visually
degraded by the presence of decomposing materials and algae blooms due
to the uptake of degraded materials that form the foodstuffs of the
algal populations.
BOD is a particularly applicable parameter for the sugar industry since
sucrose is highly biodegradable. It is significant also to ground water
pollution control in that it is possible for biodegradable organics to
seep into ground water from earthen settling or impoundage basins. The
primary disadvantage of the BOD test is the time period required for
analysis (five days is normal) and the considerable amount of care which
must be taken in order to obtain valid results.
Typical BODjj levels in both crystalline and liquid cane sugar refining
are quite high, ranging from several hundred to several thousand mg/1
for certain waste streams. Discharge of such wastes to surface waters
can result in oxygen depletion and damage to aquatic life.
Total Suspended Solids
Suspended solids include both organic and inorganic materials. The
inorganic components include sand, silt, and clay. The organic fraction
includes such materials as grease, oil, tar, animal and vegetable fats,
various fibers, sawdust, hair, and various materials from sewers.
These solids may settle out rapidly and bottom deposits are often a
mixture of both organic and inorganic solids. They adversely affect
fisheries by covering the bottom of the stream or lake with a blanket of
material that destroys the fish-food bottom fauna or the spawning ground
of fish. Deposits containing organic materials may deplete bottom
oxygen supplies and produce hydrogen sulfide, carbon dioxide, methane,
and other noxious gases.
In raw water sources for domestic use. State and Regional agencies
generally specify that suspended solids in streams shall not be present
in sufficient concentration to be objectionable or to interfere with
normal treatment processes. Suspended solids in water may interfere
with many industrial process es, and cause foaming in boilers, or
encrustations on equipment exposed to water, especially as the
68
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temperature rises. Suspended solids are undesirable in water used by
the textile, pulp and paper, beverage, dairy products, laundry, dyeing,
and photography industries, and used in cooling systems and power
plants. Suspended particles also serve as a transport mechanism for
pesticides and other substances which are readily sorbed into or onto
clay particles.
Solids may be suspended in water for a time, and then settle to the bed
of the stream or lake. These settleable solids discharged with man's
wastes may be inert, slowly biodegrabable -materials, or rapidly
decomposable substances. While in suspension, they increase the
turbidity of the water, reduce light penetration, and impair the
photosynthetic activity of aquatic plants.
Solids in suspension are aesthetically displeasing. When they settle to
form sludge deposits on the stream or lake bed, they are often much more
damaging to the life in water, and they retain the capacity to displease
the senses. Solids, when transformed to sludge deposits, may do a
variety of damaging things, including blanketing the. stream or lake bed
and thereby destroying the living spaces for those benthic organisms
that would otherwise occupy the habitat. When of an organic and
therefore decomposable nature, solids use a portion or all of the
dissolved oxygen available in the area.
Organic materials also serve as a seemingly inexhaustible food source
for sludgeworms and associated organisms.
Turbidity is principally a measure of the light absorbing,properties of
suspended solids. It is frequently used as a substitute method of
quickly estimating the total suspended solids when the concentration is
relatively low.
Total suspended solids serve as a parameter for measuring the efficiency
of waste water treatment facilities and for the design of such
facilities. In sugar refining waste waters, most suspended solids are
inorganic in nature, originating from process flows such as char wash
and carbon slurries. Barometric condenser cooling water is essentially
free of net suspended solids.
pH, Acidity, Alkalinity
Acidity and Alkalinity. Acidity and alkalinity are reciprocal terms.
Acidity is" produced by substances that yield hydrogen ions upon
hydrolysis and alkalinity is produced by substances that yield hydroxyl
ions. The terms "total acidity11 and "total alkalinity" are often used
to express the buffering capacity of a solution- Acidity in natural
waters is caused by carbon dioxide, mineral acids, weakly dissociated
acids, and the salts of strong acids and weak bases. Aklalinity is
caused by strong bases and the salts of strong alkalies and weak acids.
69
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PH. The term pH is a logarithmic expression of the concentration of
hydrogen ions. At a pH of 7, the hydrogen and hydroxyl ion
concentrations are essentially equal and the water is neutral. pH
values lower than 7 indicate acidity while values higher than 7 indicate
alkalinity. The relationship between pH and acidity or alkalinity is
not necessarily linear or direct.
waters with a pH below 6.0 are corrosive to water works structures,
distribution lines, and household plumbing fixtures and can thus add
such constituents to drinking water as iron, copper, zinc, cadmium and
lead. The hydrogen ion concentration can affect the "taste" of the
water. At a low pH water tastes "sour". The bacterial effect of
chlorine is weakened as the pH increases, and it is advantageous to keep
the pH close to 7. This is very significant for providing safe drinking
water.
Extremes of pH or rapid pH changes can exert stress conditions or kill
aquatic life outright. Dead fish, associated algal blooms, and foul
stenches are aesthetic liabilities of any waterway. Even moderate
changes from "acceptable" criteria limits of pH are deleterious to some
species. The relative toxicity to aquatic life of many materials is
increased by changes in the water pH. Metalocyanide complexes can
increase a thousand-fold in toxicity with a drop of 1.5 pH units. The
availability of many nutrient substances varies with the alkalinity and
acidity. Ammonia is more lethal with a higher pH.
The lacrimal fluid of the human eye has a pH of approximately 7.0 and a
deviation of 0.1 pH unit from the norm may result in eye irritation for
the swimmer. Appreciable irritation will cause severe pain.
ADDITIONAL PARAMETERS
Chemical Oxygen Demand
Under the proper conditions, the chemical oxygen demand (COD) test can
be used as an alternative to the BOD test. The COD test is widely used
as a means of measuring the total amount of oxygen required for
oxidation of organics to carbon dioxide and water by the action of a
strong oxidizing agent under acidic conditions. It differs from the BOD
test in that it is independent of biological assimilability. The major
disadvantage of the COD test is that it does not distinguish between
biologically active and inert organics. The major advantage is that it
can be conducted in a short period of time, or continuously in automatic
analyzers. In many instances, COD data can be correlated to BOD data
and the COD test can then be used as a substitute for the BOD test.
Considerable difficulties occur with the COD test in the presence of
chlorides, and it must be noted that barometric condenser cooling water
in a number of refineries consists of brackish water.
No definitive relationship between BOD (5-day) and COD can be
established at the present time. Therefore, it is concluded that
70
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effluent limitations guidelines and standards of performance cannot be
established for COD at present.
Bacteriological Characteristics
No bacteriological problems exist in the production of refined cane
sugar due to the fact that any bacteria present in the product prior to
evaporation are destroyed in the evaporation process. There is no
introduction of microorganisms in the refining process.
Temperature
Temperature is one of the most important and influential water quality
characteristics. Temperature determines those species that may be
present, activates the hatching of young, regulates their activity, and
stimulates or suppresses their growth and development; it attracts, and
may kill when the water becomes too hot or becomes chilled too suddenly.
Colder water generally suppresses development; warmer water generally
accelerates activity and may be a primary cause of aquatic plant
nuisances when other environmental factors are suitable.
Temperature is a prime regulator of natural processes within the water
environment. It governs physiological functions in organisms and,
acting directly or indirectly in combination with other water quality
constituents, it affects aquatic life with each change. These effects
include chemical reaction rates, enzymatic functions, molecular
movements, and molecular exchanges between membranes within and between
the physiological systems and the organs of an animal.
Chemical reaction rates vary with temperature and generally increase as
the temperature is increased. The solubility of gases in water varies
with temperature. Dissolved oxygen is decreased by the decay or
decomposition of dissolved organic substances and the decay ratep
increases as the temperature of the water increases reaching a maximum
at about 30°C (86°F). The temperature of stream water, even during
summer, is below the optimum for pollution-associated bacteria.
Increasing the water temperature increases the bacterial multiplication
rate when the environment is favorable and the food supply is abundant.
Reproduction cycles may be changed significantly by increased
temperature because this function takes place under restricted
temperature ranges, spawning may not occur at all because temperatures
are too high. Thus, a fish population may exist in a heated area only
by continued immigration. Disregarding the decreased reproductive
potential, water temperatures need not reach lethal levels to decimate a
species. Temperatures that favor competitors, predators, parasites, and
disease can destroy a species at levels far below those that are lethal.
Fish food organisms are altered severely when temperatures approach or
exceed 90°F.
71
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Predominant algal species change, primary production is decreased, and
bottom associated organisms may be depleted or altered drastically in
numbers and distribution. Increased water temperatures may cause
aquatic plant nuisances when other environmental factors are favorable.
Synergistic actions of pollutants are more severe at higher water
temperatures. Given amounts of domestic sewage, refinery wastes, oils,
tars, insecticides, detergents, and fertilizers more rapidly deplete
oxygen in water at higher temperatures, and the respective toxicities
are likewise increased.
when water temperature increases, the predominant algal species may
change from diatoms to green algae, and finally at high temperatures to
blue-green algae, because of species temperature preferentials. Blue-
green algae can cause serious odor problems. The number and
distribution of benthic organisms decreases as water temperatures
increase above 99°F, which is close to the tolerance limit for the
population, This could seriously affect certain fish that depend on
benthic organisms as a food source.
The effect of fish being attracted to heated water in winter months may
be considerable, due to fish mortalities that may result when the fish
return to the cooler water.
Rising temperatures stimulate the decomposition of sludge, the formation
of sludge gas, the multiplication of saprophytic bacteria and fungi
(particularly in the presence of organic wastes), and the consumption of
oxygen by putrefactive processes, thus affecting the aesthetic value of
a water source.
In general, marine water temperatures do not change as rapidly or range
as widely as those of freshwaters. Marine and estuarine fishes,
therefore, are less tolerant of temperature variation. Although this
limited tolerance is greater in estuarine than in open water marine
species, temperature changes are more important to those fishes in
estuaries and bays than to those in open marine areas, because of the
nursery and replenishment functions of the estuary that can be adversely
affected by extreme temperature changes.
The temperatures of waste waters discharged from cane sugar refineries
can present a problem in the case of barometric condenser cooling water
and other miscellaneous cooling waters. These streams are normally
discharged at temperatures in the range of 16° to 43°C (60° to 110°F),
but may in some instances be as high as 63*>c (145°F) . The discharge of
these heated waters, with inadequate dilution, may result in serious
consequences to aquatic environments.
72
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Nutrients
Forms of nitrogen and phosphorus act as nutrients for the growth of
aquatic organisms and can lead to advanced eutrophication in surface
water bodies.
Nitrogen. Ammonia is a common product of the decomposition of organic
matter. Dead and decaying animals and plants along with human and
animal body wastes account for much of the ammonia entering the aquatic
ecosystem. Ammonia exists in its non-ionized form only at higher pH
levels and is the most toxic in this state. The lower the pH, the more
ionized ammonia is formed and its toxicity decreases. Ammonia, in the
presence of dissolved oxygen, is converted to nitrate
-------
recommended that water containing more than 10 mg/1 of nitrate nitrogen
(NO3_-N) should not be used for infants.
Nitrates are also harmful in fermentation processes and can cause
disagreeable tastes in beer.
From the limited data available with regard to this parameter, nitrate
(NO3_-N) concentrations of 4.4 to 9.5 mg/1 occur in barometric condenser
cooling water and of 0 to 4.33 mg/1 occur in the total raw effluent from
cane sugar refineries.
Phosphorus* During the past 30 years, a formidable case has developed
for the belief that increasing standing crops of aquatic plant growths,
which often interfere with water uses and are nuisances to man,
frequently are caused by increasing supplies of phosphorus. Such
phenomena are associated with a condition of accelerated eutrophication
or aging of waters. It is generally recognized that phosphorus is not
the sole cause of eutrophication, but there is evidence to substantiate
that it is frequently the key element of all of the elements required by
fresh water plants and is generally present in the least amount relative
to need. Therefore, an increase in phosphorus allows use of other,
already present, nutrients for plant growth.
When a plant population is stimulated in production and attains a
nuisance status, a large number of associated liabilities are
immediately apparent. Dense populations of pond weeds make swimming
dangerous. Boating, water skiing, and sometimes fishing may be
impossible because of the mass of vegetation that serves as a physical
impediment to such activities. Plant populations have been associated
with stunted fish populations and with poor fishing. Plant nuisances
emit vile stenches, impart tastes and odors to water supplies, reduce
the efficiency .of industrial and municipal water treatment, impair
aesthetic beauty, reduce or restrict resort trade, lower waterfront
property values, cause skin rashes to man during water contact and serve
as a desired substrate and breeding ground for flies.
Phoshphorus in the elemental form is particularly toxic, and subject to
bioaccumulation in much the same way as mercury. Colloidal elemental
phosphorus will poison marine fish (causing skin tissue breakdown and
discoloration). Also, phosphorus is capable of being concentrated and
will accumulate in organs and soft tissues.
Experiments have shown that marine fish will concentrate phosphorus from
water containing as little as 1 ug/1.
From the limited amount of data available with regard to this parameter,
total phosphorus concentrations of 0-2.9 mg/1 occur in barometric
condenser cooling water and of 0-2.8 mg/1 occur in the total raw
effluent from cane sugar refineries.
74
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Total Dissolved solids
In natural waters the dissolved solids consist mainly of carbonates,
chlorides, sulfates, phosphates, and possibly nitrates of calcium,
magnesium, sodium, and potassium, with traces of iron, manganese and
other substances. In cane sugar refinery effluents, dissolved solids
are more often organic in nature, originating from sucrose.
Many communities in the United States and in other countries use water
supplies containing 2000 to 4000 mg/1 of dissolved salts, when no better
water is available. Such waters are not palatable, may not quench
thirst, and may have a laxative action on new users. Waters containing
more than UOOO mg/1 of total salts are generally considered unfit for
human use in temperate climates, although in hot climates such higher
salt concentrations can be tolerated. Waters containing 5000 mg/1 or
more are reported to be bitter and act as bladder and intestinal
irritants. It is generally agreed that the salt concentration of good,
palatable water should not exceed 500 mg/1.
Limiting concentrations of dissolved solids for fresh-water fish may
range from 5,000 to 10,000 mg/1, according to species and prior
acclimation. Some fish are adapted to living in more saline waters, and
a few species of fresh-water forms have been found in natural waters
with salt concentrations ranging from 15,000 to 20,000 mg/1. Fish can
slowly become acclimated to higher salinities, but fish in waters of low
salinity cannot survive sudden exposure to high salinities, such as
those resulting from discharges of oil-well brines. Dissolved solids
may influence the toxicity of heavy metals and organic compounds to fish
and other aquatic life, primarily because of the antagonistic effect of
hardness on metals.
Waters with total dissolved solids over 500 mg/1 have decreasing utility
as irrigation water. At 5,000 mg/1 water has little or no value for
irrigation.
Dissolved solids in industrial waters can cause foaming in boilers and
cause interference with cleanliness, color, or taste of many finished
products. High contents of dissolved solids also tend to accelerate
corrosion.
Specific conductance is a measure of the capacity of the ions present in
solution to convey an electric current. This property is related to the
total concentration of ionized substances in water and to water
temperature. This property is frequently used as a substitute method of
quickly estimating the dissolved solids concentration.
Total dissolved solids may reach levels of 1,000 milligrams per liter in
certain refinery waste water streams. In once-through barometric
condenser cooling water, where entrained sucrose contributes dissolved
solids, the concentration is typically 20 milligrams per liter. Where
land impoundage of waste waters is employed, the dissolved solids
concentration in seepage may considerably exceed raw waste water values.
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Sugar Analysis
Analysis for sucrose content is important in process control as an indi-
cator of sugar loss. The two common tests used are the alphanapthol and
resorcinol methods. Neither of these methods provides high accuracy at
low sucrose concentrations, but each may serve a useful purpose by
indicating slug loads of sugar and thus provide a danger signal for
improper operation of evaporators or vacuum pans, or for spills of sugar
or molasses. Due to the inaccuracy of the test at low levels and to the
fact that sugar content is also measured by BOD, the sugar analysis is
not an adequate parameter for guidelines establishment.
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SECTION VII
CONTROL AND TREATMENT TECHNOLOGY
Current technology for the control and treatment of cane sugar refinery
waste waters consists primarily of process control (recycling and reuse
of water, prevention of sucrose entrainment in barometric condenser
cooling water, recovery of sweet waters), impoundage (land retention),
and disposal of process water to municipal sewer systems.
The general scope of current technology is that the volume of process
water is sufficiently low that it can be handled by end-of-line
treatment and disposal systems, whereas the much higher volume of
barometric condenser cooling water makes it impractical to treat. This
position is illustrated by the fact that few refineries release sub-
stantial amounts of untreated process waters to receiving streams while
all but five refineries discharge barometric condenser cooling water to
surface water bodies.
IN-PLANT TECHNOLOGY
IN-PLANT CONTROL MEASURES AND TECHNIQUES IN THE CANE SUGAR REFINING
INDUSTRY ~
In-plant control measures are essential in the total effort for pollu-
tion control in cane sugar refineries. In-plant control refers to the
operational and design characteristics of the refinery and their impact
on total waste management. Specific elements are water utilization and
conservation, housekeeping techniques, and any operational or design
factors that affect waste water quantity and/or quality. A primary
portion of in-plant control is for the prevention of sugar loss and thus
is an extension of historical efforts. To the refiner the loss of sugar
in waste water represents lost money; to the environmentalist it is an
organic pollutant. Other measures of in-plant control include the
facilitation of dry-handling techniques for sludges and filter cakes,
maximum recovery and reuse of various process streams, and improved
housekeeping practices.
Raw Sugar Handling. Raw sugar is normally delivered to refineries by
truck, rail car, barge, or ship. The unloading of the raw sugar at the
receiving area offers an opportunity for sugar spillage, and the
periodic washdown of the receiving area produces a variable waste stream
with a high sugar content. In one refinery visited, raw sugar conveyor
belts were routinely washed down and the resulting sugar solutions were
allowed to flow into a surface water body, carrying with them an
indeterminable amount of BOD5.
Most refineries recover floor washings in the receiving area to some
extent—some refineries almost in total. The practice in some re-
fineries is to recover as much spilled sugar as possible by sweeping,
then discharge subsequent rinse water to waste. A minimal effort at
77
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sugar loss prevention through equipment modification and improved
housekeeping can essentially prevent the loss of sugar and its resulting
pollutant load from the raw sugar receiving area.
Truck and Car Wash. The tank trucks and rail tank cars that transport
liquid sugar and edible syrups must be maintained under sanitary con-
ditions. This normally involves cleaning of the tanks with steam and
water after each use. The first few minutes of washing produces a sweet
water that is of sufficient sucrose concentration to allow economical
recovery for processing. The sucrose concentration in the wash water
effluent after the first few minutes is considered by most refiners to
be too low for recovery and is wasted. This stream can be minimized by
maximizing recovery, but in any event the stream is small in volume and
a minor contribution to total process waste water flow.
Floor Wash. Since any bacteriological contamination to the raw sugar
syrup prior to evaporation is eliminated by evaporation, the recovery of
essentially all floor wash drains as sweet water is possible and is
practiced in some refineries,
Barometric Condenser Cooling Water. The development of calandria-^type
vacuum pans and evaporators in the sugar industry has afforded increased
boiling rates, but at the same time the possibility of sucrose
entrainment in the barometric condenser cooling water has increased*
Sucrose entrainment represents an economic loss to the refiners as well
as an organic pollutant load to the environment in the condenser water
effluent. All sugar refineries employ some means to reduce entrainment,
with the motive in the past being primarily an economic one.
Entrainment is a result of liquid droplets being carried out with water
vapors in evaporators and vacuum pans. There are three important fac-
tors which affect the efficiency of entrainment control:
(1) Height of the vapor belt (vapor height)
(2) Operation and maintenance
(3) Liquid-vapor separation devices
One of the most important factors in determining liquid carryover is the
height the liquid bubbles must rise before entering the relatively high
velocity area of the discharge tube. If the height of the vapor belt is
of sufficient magnitude, most liquid droplets will fall back into the
boiling liquor due to gravity and be removed from the vapor before
exiting the evaporator or vacuum pan. It has been found from experience
that the vapor height should be at least 250 percent of the height of
the calandria tubes to minimize entrainment. Vapor heights in the cane
sugar refining industry have been generally found to be more adequate
than those in raw sugar factories. However, when existing vapor heights
are insufficient, they can be increased by installing a spacer in
existing equipment* This has been done in several cases for the purpose
of increasing evaporation capacity, but entrainment reduction has been a
secondary result.
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In addition to proper design, proper operation of the evaporators and
vacuum pans is essential in minimizing sucrose entrainment. It is
important to maintain the liquid level in evaporators and vacuum pans
near the design level; in essence, if the liquid level is increased, the
vapor height is decreased. An important variable which must be
carefully controlled is the pressure inside the vessel. If the pressure
is suddenly decreased, flash evaporation is likely to occur resulting in
an increase in boiling rate and subsequent liquid carryover. Automatic
controls are available for the operation of evaporators and pans and
these have been installed in a number of refineries. The typical re-
finery has liquid level controllers on all evaporator bodies and
absolute pressure control on last bodies of multiple effects and on
vacuum pans.
In addition to proper design and operation, a number of devices can be
installed to separate liquid droplets from the vapors. Baffle
arrangements which operate on either centrifugal or impingement prin-
ciples are commonly used. The Serner separator (7), a type of baffle
arrangement, is used in several refineries. Figure 16 shows the ef-
fectiveness of entrainment prevention devices, including Serner
separators, used in conjunction with other baffles and direction
reversals, based on experience in a particular installation. The total
BOD5 reduction in this case is 84 percent. Higher reductions are
considered possible with careful design coupled with proper operation.
Demisters have been found to be applicable to entrainment reduction in
certain cases. These devices, which consist basically of a wire mesh
screen serving the dual purpose of impingement and direction change,
were used to a large extent in the Cuban sugar industry before 1960 and
have been used to a limited extent in the United States, One refinery,
upon the installation of demisters in most of its evaporators and vacuum
pans experienced a 50 percent reduction in barometric condenser cooling
water COD. However, during the same maintenance program, changes were
made in the baffles and other control equipment, and the amount of
reduction due .solely to the demisters remained unclear.
At least two major refineries use partial surface condensers as heat
exchangers in the exhaust ducts prior to barometric condensation. These
units not only affect liquid-vapor separation but also capture heat from
the vapors, and have been installed for the latter purpose.
Total surface condensers have also been considered but in general they
have been rejected, primarily due to the costs associated with
installation, but also for a number of other reasons including
operational problems and the questionable benefits associated with their
use. A total surface condenser condenses vapors by indirect (non-
contact) cooling resulting in no sucrose loss in condenser water and a
stream of hot condensate that must be discharged because of its low
sucrose content,
One potential problem with surface condensers is fouling. Most re-
fineries use low quality surface (river or estuarine) water for conden-
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WHITE SUGAR
VACUUM FANS
J
SOFT VACUUM
PANS
TRIP1 E EFFFCT
EVAPORATOR
(A-LIQOUR)
OlIAn FFFFCT
EVAPORATOR
SWEET WATER
MISCELLANEOUS
EVAPORATOR
Tr
5252 Kg
F
183 Kg
752 Kg
P
819 Kg
P
43 Kg
ENTRAINMtNT
SEPARATION
i
4838 Kg
ETURN TO PROCES
ENTRAPMENT
SEPARATION
i
58 Kg
RETURN TO PROCES
ENTRAPMENT
SEPARATION
1
701 Kg
ETURN TO PROCES
ENTRAPMENT
SEPARATION
I
263 Kg
£TURH TO PROCES
ENTRAPMENT
SEPARATION
414 Kg
125 Kg
S
51 Kg
556 Kg
13 Kg
RIVER WATER
1
CONDENSER
RIVER WATER
1
CONDENSER
RIVER WATER
I
CONDENSER
RIVER WATER
1
CONDENSER
RIVER WATER
CONDENSER
414 Kg
DISCHARGE
>
125 Kg
DISCHARGE
51 Kg
DISCHARGE
556 Kg
DISCHARGE
^
13 Kg
DISCHARGE
30 Kg
RETURN TO PROCESS
FIGURE 16
ENTRAPMENT REDUCTION
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ser cooling. While total surface condensers have not been used in re-
fineries, a comparison can be made with surface heat exchangers used for
air and oil coolers of turbine generators. The general experience of
the sugar industry has been that raw river water is unacceptable for
such applications because of fouling (13).
A second problem area in the use of surface condensers is vacuum control
on the vacuum pans. For proper operation of a vacuum pan, an absolute
pressure with a tolerance of plus or minus 0.003 atmospheres (0.1 inch
mercury) must be maintained. Adjustments to the absolute pressure, made
necessarily by variations in calandria steam pressure, feed density, and
non-condensible leakage, can be made with a barometric condenser by
changing the flow in the condenser; however, the lag time associated
with a surface condenser makes absolute pressure control considerably
more difficult and could actually increase sugar entraiiiment.
The physical installation of surface condensers would be a problem in
many refineries, and in some cases an almost insurmountable one. Ver-
tical height when unavailable can often be obtained by raising the roof
of a refinery, but horizontal space may be achieved only with
considerable difficulty. The weight of surface condensers could
possibly cause structural problems in older refineries. The units would
have to be installed on the fourth or fifth floor of a building that
might be a century old. The structural analysis required to ensure the
feasibility of doing so could be extremely difficult.
USCSRA has estimated (13) that in a typical 1900 metric ton (2100 ton)
refinery, surface condensers would approximately double required pumping
energy, increase electrical requirements by about 1000 kilowatts, and
require 11,350 to 13,620 kilograms per hour (25,000 to 30,000 pounds per
hour) additional steam capacity.
Recirculation of barometric condenser cooling water through a cooling
tower is feasible and is practiced at three refineries. Spray ponds
have proved to be feasible for the cooling and recirculation of
barometric condenser cooling water for two small rural refineries, for
several cane sugar factories, and for a number of beet sugar plants.
However, the land required for these facilities generally prohibits
their use for urban refineries.
One large urban refinery recycles barometric condenser cooling water
through a cooling tower and discharges on the average about two to three
percent of the flow as blowdown. Cooling towers, while expensive, might
be applicable to other refineries and offer a means of reducing waste
water volume; however, in northern climates winter temperatures would
interfere with operation, and in dense urban areas wind blown sprays and
odors can present problems. These problems can be reduced by proper
design and operation, and probably eliminated for most wind conditions.
Filter Cake. Most refineries use pressure filters such as the Valley or
Industrial type for removing impurities from sugar liquors. Filter aid,
usually diatomaceous earth, is used with the filters. When the pressure
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drop across the filter increases to an unacceptable value or when the
filter efficiency drops, the filter cake is removed. The desweetened
cake is semi-dry (about 50 percent moisture) and may be handled in that
form or it may be slurried for pumping. In the dry form it is normally
conveyed to trucks which in turn transport the material to landfill or
other land disposal. In the slurried form it may be pumped to
impoundage or to a municipal treatment system. A major portion of the
cake can be recovered in a kiln by revivification of the filter aid. An
existing system for filter cake recycle and land disposal is illustrated
in Figure 17. In this system approximately 80 percent of the cake is
conveyed to a multiple hearth kiln where the cake is heated to about
816°C (lr500°F). Revivified filter aid is discharged from the kiln,
pulverized, and returned to the filtration step of the refining process.
Makeup filter aid is added to the system as required. The installation
of a continuous carbonation process for lime mud slurry, to make it
suitable for vacuum filtration and removal of sugar by washing, is
reported by one refinery to have reduced total settleable solids by 96
percent and BOD5 by 20 percent.
Adsorbent Regeneration. In-plant modifications for the reduction of
waste waters resulting from the regeneration of bone char, carbon
columns, and ion-exchange resins are practically non-existent, although
there are some minor, mainly operational, modifications to reduce waste
water loads which include:
(1) Recovery of waste waters with lower sucrose
concentrations, i.e., recovery of a greater
portion of spent char wash water,
(2) Reduction in the volume of wash water used
to sweeten off bone char and carbon columns,
and greater dependence on volatilization of
organics,
(3) Elimination or reduction in the use of ion-
exchange as an organic color remover.
These modifications are merely proposals and the implications of their
adaptation are not fully known; research on this subject is needed. At
present, control and treatment of these wastes is restricted to end-of-
line treatment.
WASTE TREATMENT TECHNOLOGY
TREATMENT AND DISPOSAL TECHNOLOGY CURRENTLY AVAILABLE TO THE CANE SUGAR
REFINING INDUSTRY
The following is a discussion of various end-of-pipe treatment
technologies available to the cane sugar refining segment of the cane
sugar processing industry. These technologies range from preliminary
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1
Industrial
Desweetening
Filters
hrom Fiitration
15 kkg solids/day
i
Sweet
Water
to
Process
Return to
Process
15 kkg Solids/Day
Cake
Discharge
15 kkg Solids/Day
Cake to
Landfill
Disposal
3 kkg Solids/Day
0.18 kkg BOD/Day
Regeneration
Recycle
Kiln
12 kkg Solids/Day
Make up
3 kkg Solids/nay
FIGURE 17
FILTER CAKE RECYCLE SYSTEM
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treatment systems to advanced waste treatment systems and systems of
ultimate disposal.
Preliminary Treatment Systems
Flow Equalization Tanks. Flow equalization facilities consist of a
holding tank and pumping equipment designed to reduce the fluctuations
in flow of waste effluent streams. They can be economically
advantageous whether a processing plant is treating wastes or
discharging into a city sewer after some pretreatment. The equalizing
tank stores waste water either for recycle or to feed the flow uniformly
to treatment facilities throughout a 24-hour period.
Sedimentation. Sedimentation without prior chemical addition may prove
to be an effective means of solids removal. This can serve the purpose
of reducing the solids loading on another part of the treatment system.
If settling tanks rather than lagoons are used, the settled solids must
be collected and withdrawn from the bottom of the tank. Solids may be
continuously collected and withdrawn by the utilization of mechanical
scrapers which move slowly along the bottom of the settling tank.
Chemical Treatment
p_H Adjustment. Acids and caustics are used to remove scale deposits
from evaporators and vacuum pans. Lime or phosphoric acid may be added
to aid in the clarification of screened melt liquor. Biological systems
function at their optimum when the pH is neutral (7.0), but will operate
effectively within the pH range of 6.0 - 9.0. when necessary, the pH
may be adjusted, with the proper addition of acid or base, to within
these limits; this assures the proper environment for the active biota.
Chlorinatign. Chlorination is used for odor control and also in
municipal water treatment as a disinfectant. Chlorine is available in
granular, powdered, or liquid form. Adding chlorination to a treatment
process presents the need to construct chlorine handling facilities
consisting of storage, phase conversion, mixing, and effluent detention
facilities. Since chlorine is a hazardous substance, special safety
precautions in storage and handling are required. Dose rates for
chlorine for domestic sewage are usually in the range of 3 to 15 parts
per million with detention times of up to one hour in duration. Dosage
should be high enough to provide a chlorine residual in the effluent to
assure protection against pathogenic bacteria.
Chlorination is used to inhibit algae growth. This is of special
importance for correcting one type of bulking sludge problem in some
activated sludge plants,
Chlorination may also be used for disinfection and to oxidize residual
organic material. It is practiced on treated waste waters to a limited
degree. This practice can be expected to become common in order to
permit the recycle of highly purified waters.
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Chlorine also provides a residual protection against bacteria that other
disinfectants such as ozone or bromine do not provide.
Nutrient Addition. Cane sugar refinery waste waters are deficient in
both nitrogen and phosphorus with regard to the ratio of these elements
to organic matter which is required for optimum biological treatment.
This situation may be corrected with nutrient addition (ammonia and
phosphoric acid, for example) prior to biological treatment. The
nutrients should be added after primary settling to avoid their loss in
the solids removed by the settling device.
Primary Treatment Systems
Settling,
suspended
Sedimentation, and Clarification.
_ A substantial portion of
settling, sedimentation, or
solids may be separated by
clarification. Settling involves the provision of a sufficiently large
tank or pond in order that the velocity of the waste water streams be
reduced. The forces resulting from density differences between the
suspended solids and the waste water come into affect and the solids
settle out.
Clarifiers operate on the same principle, with the addition of mild
mechanical agitation to assist in the settling process and in the
removal of suspended solids. Clarifiers are also used as a part of the
activated sludge process, serving as an initial step preceding
biological treatment and to separate sludge for return to the aeration
step or to anaerobic digestion.
Settling ponds, or Clarifiers are also used as a final step in biological
systems for the removal of biological solids prior to the- discharge of
treated waste waters.
Settled solids from the bottom of the clarification unit in the form of
a sludge may be pumped to a rotary vacuum filter, where the slurry is
concentrated by removal of water which is returned to the clarifier.
The outside surface of the filter cylinder is covered with a filter
medium (screen or cloth) . The lower portion of the filter is suspended
in the liquid slurry. As the drum rotates, the vacuum which is
maintained within the cylinder forces liquid into the cylinder while
leaving a solids layer on the outside of the filter medium. As the drum
rotates, a scraper mechanism removes solids from the surface of the
filter medium. This method of solids thickening has been widely used in
both industrial and municipal waste water treatment.
Biological Treatment Systems
The treatment of waste effluents by biological methods is an attractive
alternative when a high portion of the biodegradable material is in
soluble form, as is the case in the cane sugar refining segment of the
sugar processing category.
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Many types of microorganisms remove organic materials from waste waters.
Those most commonly used in treatment systems are heterotrophs, which
utilize organic carbon as an energy source and for growth. Some are
aerobic and require molecular oxygen for converting wastes to carbon
dioxide and water. Others are anaerobic and grow in the absence of
molecular oxygen. Anaerobic microorganisms grow more slowly than do
aerobes and produce less sludge per unit of waste treated than do
aerobic microorganisms. Anaerobes also release acids and methane, and
their actions on sulfur-containing waste waters may create odor
problems. Some microorganisms are facultative or grow in either an
aerobic or anaerobic environment.
The biological treatment of many food processing wastes often lacks
necessary nutrients within the waste to sustain desirable biological
growth. Nutrient, nitrogen and phosphorus, addition may be required for
effective treatment of cane sugar refining wastes. This could be
economically achieved by the addition of nutrient-rich wastes from
another source for combined treatment.
A discussion of the various methods of biological treatment is presented
in the following paragraphs.
Activated sludge. in this case the active biota is maintained in
suspension in the waste water. Air, supplied to the system by
mechanical means, mixes the reaction medium and supplies the
microorganisms with the oxygen required for their metabolism. The
microorganisms grow and feed on the nutrients in the inflowing waste
waters. There are fundamental relationships between the growth of these
microorganisms and the efficiency of the system to remove BODji.
A number of activated sludge systems have been designed, all of which
have their own individual configurations. Basically, these designs
consist of some type of pretreatment, usually primary sedimentation,
followed by aeration, and by secondary sedimentation which allows the
sludge produced to separate, leaving a clear effluent. Portions of the
settled sludge are recirculated and mixed with the influent to the
aeration section, usually at a proportion ranging from between 10 to 100
percent, depending upon the specific modification to the basic activated
sludge process.
The goal of these plants is to produce an actively oxidizing microbial
population which will also produce a dense "biofloc" with excellent
settling characteristics. Usually, an optimization of floe growth and
overall settleability is necessary since very active microbial
populations do not always form the best floes.
The extended aeration modification of the activated sludge process is
similar to the conventional activated sludge process, except that the
mixture of activated sludge and raw materials is maintained in the
aeration chamber for longer peiods of time. The common detention time
in extended aeration is one to three days, rather than the six hours
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detention time common to conventional activated sludge systems. During
this prolonged contact between the sludge and raw wastes, there is ample
time for organic matter to be adsorbed by the sludge and also for the
organisms to metabolize the removal of organic matter which has been
built up into the protoplasm of the organism. Hence, in addition to
high organic removals from the waste waters, substantial decomposition
of the organic matter of the microorganisms into stable products may
occur and consequently less sludge will have to be handled.
In extended aeration, as in the conventional activated sludge process,
it is necessary to have a final sedimentation tank. Some of the solids
resulting from extended aeration are rather finely divided and settle
slowly, therefore requiring a longer period of settling.
Activated sludge in its various forms is an attractive alternative for
the treatment of cane sugar refining waste waters. Conventional design
criteria are not directly transferable from municipal treatment
applications. However, high levels of treatment efficiency are possible
at the design loadings normally employed in treating other types of high
strength organic wastes.
Within other industrial point source categories, such as the fruit and
vegetable processing industry, activated sludge treatment plants are
capable of removing 95 percent or better of the influent BOD5 based upon
proper nutrient addition, design, and operation. The general experience
has been that biological solids separation problems can be avoided if
the dissolved oxygen concentration remains above zero throughout the
aeration basin, if strong, highly concentrated waste releases are
minimized through proper management practices, and if sufficient amounts
of nitrogen are present to maintain a critical nitrogen-to-BOD5. ratio.
Activated sludge systems require less room than other high reduction
biological systems, but have higher capital and operating costs. It is
felt that properly designed and operated systems are capable of treating
cane sugar refining waste waters to achieve high reductions of BOD.
Biological Filtration (Trickling Filtration). The purpose of the
biofilter system is to change soluble organic wastes into insoluble
organic matter primarily in the form of bacteria and other higher
organisms. As the filter operates, portions of the biological growth
slough off and are discharged as humus with the filter effluent.
Usually, some physical removal system is required to separate this
insoluble organic material which can be treated by other suitable
methods, usually anaerobic fermentation in a sludge digester.
Trickling filters are usually constructed as circular beds of varying
depths containing crushed stone, slag, or similar hard insoluble
materials. Liquid wastes are distributed over this bed at a constant
rate and allowed to "trickle" over the filter stones. Heavy biological
growths develop on the surface of the filter "media" throughout the
depth of the filter and also within the interstitial spaces.
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The biological film contains bacteria, (Zooglea, Sphaerotilus, and
Beggiatoa); fungi (Fusarium, Geotrichum, Sepedonium); algae, both green
and blue-green (Phormidium, Ulothrix, Mononostrona) ; and a very rich
fauna of protozoa. A grazing fauna is also present on these beds
consisting of both larval and adult forms of worms (Oligochae^a),
insects (Diptera and Coleoptera among others), and spiders and mites
(Arachnida) .
A common problem with this type of filter is the presence of flies which
can become a severe nuisance. Insect prevention can usually be
prevented by chlorinating the influent or by periodically flooding the
filter.
Recirculation of waste water flows through biological treatment units is
often used to distribute the load of impurities imposed on the unit and
stabilize the applied flow rates. Trickling filter BODS removal
efficiency is affected by temperature and the recirculation rate.
Trickling filters perform better in warmer weather than in colder
weather. Recirculation of effluent increases BOD5 removal efficiency as
well as keeping reaction type rotary distributers moving, the filter
media moist, organic loadings relatively constant, and increasing
contact time with the biological mass growing on the filter media.
Furthermore, recirculation improves distribution, equalizes effluent
flow rates, obstructs entry and egress of flies, freshens incoming and
applied waste waters, reduces the chilling of filters, and reduces the
variation in time of passage through the secondary sedimentation unit.
Trickling filter BOD5 removal efficiency is inversely proportional to
the BOD5 surface loading rate; that is, the lower the BODji applied per
surface area, the higher the removal efficiency.
Other Aerobic Prgcesses. Aerated lagoons use either fixed mechanical
turbine-type aerators, floating propellor-type aerators, or a diffused
air system for supplying oxygen to the waste water. Aerated lagoons can
rapidly add dissolved oxygen to convert anaerobic waste waters to an
aerobic state, providing additional BODji reduction, and require a
relatively small amount of land. The system thus approaches conditions
similar in nature to extended aeration without the recycle of sludge.
Disadvantages of this system are the high power requirements and the
small reductions in suspended solids attained. Aerated lagoons
generally do not reduce BOD5 and suspended solids adequately to be used
as the final stage of a high performance biological treatment system.
Aerated lagoons usually act as the final stage of secondary treatment
and are followed by aerobic lagoons which capture suspended solids and
afford further BOD5 reduction.
Aerobic ponds are large surface area, shallow lagoons, designed for high
detention times; thus, they require large areas of land. Aerobic
lagoons serve a three-fold function in waste reduction: they allow
solids to settle out, equalize and control flow, and permit the
-------
stabilization of organic matter
microorganisms and also by algae.
by aerobic and facultative
Algae growth is common in aerobic lagoons and represents a drawback when
aerobic lagoons are used for final treatment, in that algae may escape
into the receiving waters. Algae in the lagoon, however, play an
important role in stabilization. They utilize CQ2, sulfates, nitrates,
phosphates, water, and sunlight to synthesize their own organic cellular
matter and give off free oxygen. The oxygen may then be used by other
microorganisms for their metabolic processes. However, when algae die
they release their organic matter in the lagoon, causing a secondary
loading.
Advantages of aerobic lagoons are that they reduce suspended solids,
oxidize organic matter, and permit flow control and waste water storage.
Disadvantages are the large amounts of land required, the algae growth
problem, and odor problems.
Aerobic lagoons usually are the last stage in secondary treatment and
frequently follow anaerobic or aerated lagoons. Large aerobic lagoons
allow plants to store waste water discharges during periods of high flow
or to store for irrigation. These lagoons are particularly popular in
rural areas where land is available and relatively inexpensive.
Anaerobic Processes. Anaerobic or facultative microorganisms, which
function in~~the "absence of dissolved oxygen, break down organic wastes
to intermediates such as organic acids and alcohols. Methane bacteria
then convert the intermediates primarily to carbon dioxide and methane,
and where sulfur compounds are present, to hydrogen sulfide. Anaerobic
processes are economical because they provide high overall removal of
BOD5 and suspended solids with no power cost (other than pumping) and
with low land requirements. Two types of anaerobic processes are
possible: anaerobic lagoons and anaerobic contact systems.
Anaerobic lagoons may be used as the first step in secondary treatment.
These are relatively deep, low surface area systems, with several days
of detention time.
Plastic covers of nylon-reinforced Hypalon, polyvinyl chloride, and
styrofoam can be used to retard heat los s, to ensure anaerobic
conditions, and to retain obnoxious odors, properly installed covers
provide a convenient method for collection of methane gas.
Influent waste water flow should be near, but not on, the bottom of the
lagoon. In some installations, sludge is recycled to ensure adequate
anaerobic seed for the influent. The effluent discharge point should be
located to prevent short-circulating of the influent stream and to
prevent carry-over of the scum layer.
Advantages of an anaerobic lagoon system are initial low cost, ease of
operation, and the ability to handle shock waste loads and yet continue
to provide a consistent quality effluent. The major disadvantage of an
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anaerobic lagoon is potential odor problems although odors are not
usually a serious problem at well managed lagoons.
Anaerobic lagoons used as the first stage in secondary treatment are
usually followed by aerobic lagoons. Placing a small, mechanically
aerated lagoon between the anaerobic and aerobic lagoons is another
alternative.
The anaerobic contact system requires far more equipment for operation
than do anaerobic lagoons, and consequently is not as commonly used.
The equipment consists of equalization tanks, digesters with mixing
equipment, a.ir or vacuum gas stripping units, and sedimentation tanks
(clarifiers). Equalized waste water flow is introduced into a mixed
digester where anaerobic decomposition takes place; detention times of
three to twelve hours are common. After gas stripping, the digester
effluent is clarified and the sludge partially recycled.
Advantages of the anaerobic contact system are: high organic waste load
reduction in a relatively short time, production and collection of
methane gas that can be used to maintain a high temperature in the
digester and also to provide auxilary heat and power, good effluent
stability even at times of waste load shocks, and application in areas
where anaerobic lagoons cannot be used because of odor or soil
conditions. Disadvantages of anaerobic contractors are the high initial
and maintenance costs and the potential of odor emissions from the
clarifiers.
Advanced Treatment Systems
A discussion of advanced treatment methods is presented; these methods
provide a means of further polishing the effluent from the biological
treatment systems previously described. While an individual technology
discussed may not of itself constitute a complete process, upon its
addition to a treatment system it would become part of a complete
treatment process.
Carbon Adsorption. The reduction of tastes and odors in water supplies
by adsorption of the offending substances on activated carbon is
probably the most important direct use of adsorption technology used in
water treatment. Columns or beds of granular activated carbon are
employed for concentrating organic pollutants from water for purposes of
anlysis or for removal of the pollutants.
The fixed bed or countercurrent operation is the most effective and
efficient way of using activated carbon. The influent comes into
contact with the adsorbent along a gradient of mounting residual
activity providing that the most active carbon gives a final polish to
the effluent stream.
Partial regeneration of carbon by thermal volatilization or steam
distillation of organic adsorbates is possible, but available
regeneration procedures will have to be improved or new ones invented if
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adsorption is to become a widely useful operation in water treatment.
However, cane sugar refineries use multi-hearth furnaces to regenerate
the bone char or granular activated carbon used as a decolorant of sugar
liquor. This capability could minimize the difficulties and costs
associated with regeneration of any activated carbon utilized in waste
water treatment.
Granular activated carbon can replace other filtering materials in
structures not unlike present-day rapid sand filters. Beds of granular
activated carbon can, in fact, be made to perform as both filters and
adsorbents. However, activated carbon filters must be somewhat deeper
than sand filters, even though they may be operated at somewhat higher
rates of flew per unit volume of bed. In this way, beds of spent
granular activated carbon or bone char may be utilized to act as a
polishing step to further remove biological solids resulting from the
biological treatment of refinery waste waters.
Filtration. Two types of filtration will be considered in this
discussion: (1) sand filtration, both slow and rapid, and (2)
diatomaceous earth filtration.
A slow sand filter is a specially prepared bed of sand or other material
fines on which doses of waste water are intermittently applied and from
which the effluent is removed by an under-drainage system. The solids
removal occurs mainly at the surface of the filter. BOD removal occurs
primarily as a function of the degree of solids removal although some
biological action occurs in the top inch or two of sand. Effluent from
the sand filter is of a high quality with BOD5 and suspended solids
concentrations very low.
Slow sand filters require larger land areas than rapid sand filter
facilities; however, slow sand filters may operate long periods of time
without cleaning, whereas rapid sand filters are usually cleaned by
backwashing periodically.
Slow sand filters require no extra preparatory water treatment prior to
filtration, although it is recommended. Rapid sand filters are designed
to remove the solids remaining after treatment by coagulation,
flocculation, and sedimentation. Construction costs of slow sand
filters are relatively high due to the large area requirements; however,
operating and maintenance costs are relatively low because slow sand
filters may operate for long durations. Rapid sand filters have a
relatively low construction cost due to low land requirements; however*
operating and maintenance costs are relatively high as they cannot be
operated for long periods of time without backwashing.
Rapid sand filters are subject to a variety of ailments such as cracking
of the bed, formation of mud balls, plugging of portions of the bed, jet
actions at the gravel-sand separation plane, sand bails, and sand
leakage into the under-drainage systems. Usually these problems can be
minimi3ed or eliminated by proper design and plant operation. Sand
-------
filters are well noted for their efficient removal of bacteria, color,
turbidity, and large microorganisms.
Diatomaceous earth filters have found use as: (1) mobile units for
water purification and (2) stationary units for swimming pools and
general water supplies. Skeletons of diatoms mined from deposits
compose the diatomaceous earth. The filter medium is a layer of
diatomaceous earth built upon a porous septum. The resulting pre-coat
is supported by the septum, which serves also as a drainage system.
Water is strained through the pre-coat unless the applied water contains
so much turbidity that the unit will maintain itself only if additional
diatomaceous earth, called body feed, is introduced into the incoming
water to preserve the open texture of the layer. There are few known
applications as yet in the food processing field.
Microscreening. Microsreening has been a viable solids-removal process
for many years. A microsreen consists of a rotating drum with a screen
or fabric constituting the periphery. Feedwater enters the drum
internally and passes radially through the screen with the concomitant
deposition of solids on the inner surface of the screen. At the top of
the drum, jets of water are directed onto the screen to remove deposited
solids. This backwash stream of dislodged solids and washwater is
captured in a receiving hopper inside the drum and flows out through the
hollow axle of the unit. In order to reduce slime growths on the
screen, an ultraviolet lamp is continually operated in close proximity
to the screen. The driving force for the system is the head
differential between the inside and outside of the screen. As solids
are removed on the screen a mat is formed which improves the solids
removal efficiency and also results in increased head loss through the
screen. The maximum head loss is usually limited to 0.15 meters (6
inches) in order to prevent screen damage. In order to prevent the
limiting head loss from being exceeded, drum speed and wash water
pressure are increased. In newer units, automatic controls handle these
adjustments.
Individual studies have demonstrated the effects of a number of design,
maintenance, and operational factors on the performance of
microscreening units:
Design:
Approximately one-half of the applied screen wash water
penetrates and is removed with the solids-bearing stream.
The solids-bearing waste stream is usually returned to the main
treatment plant.
It is desirable to have gravity flow from the clarifier to the
microscreener to avoid shearing of the more fragile solids.
Prechlorination should
screen.
be avoided in order to protect the
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Chloride concentrations exceeding 500 mg/1 may cause corrosion.
problems.
Microscreens do not successfully remove floe particles resulting
from coagulation by chemicals such as aluminum sulfate.
Maintenance:
Screens for the pressure washing system may tend to clog due to
the presence of grease in the effluent.
Most units require frequent cleaning with a hypochlorite
solution which entails a few hours of removal from service in
order to clean the fabric.
High iron or manganese concentrations in the feed may
necessitate an occasional acid wash of the screen to destroy the
resulting film buildup.
Operation:
Minimum drum speeds (consistent with head loss limitations) will
give the greatest removal of suspended solids.
Higher pressures are more beneficial with regard
washing system than greater quantities of water.
to the jet
— High solids loadings can cause severe reductions (of up to two-
thirds of design capacity) in throughput as well as increasing
acceleration of slime buildup.
Reverse Osmosis. Osmotic pressure acts as the driving force as water
molecules pass through a semi-permeable membrane from a dilute to a
concentrated solution in search of equilibrium. This natural response
can be reversed by placing the concentrated solution under hydrostatic
pressures higher than the osmotic pressure.
A good deal of experimentation has been carried out in an attempt to
apply membrane processes including reverse osmosis, ultrafiltration, and
electrodialysis to the treatment of industrial waste waters. Reverse
osmosis has the capability of removing dissolved and suspended materials
of both organic and inorganic nature from waste streams. However,
organic-laden streams tend to foul reverse osmosis membranes resulting
in substantially decreased throughput.
Recent developments of the spiral or hollow tube reverse osmosis systems
permit large membrane areas to be incorporated into a small space, thus
permitting large volumes of water to be treated. The use of either the
spiral or hollow tube system requires that all particles larger than 10
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to 20 microns be removed
reverse osmosis system.
from the waste stream before entering the
Disadvantages of the reverse osmosis process are the relatively high
costs of treatment when applied to large volumes of water, the poteritial
of bacterial growth on or near the membrane and its damaging effect on
the membrane, and the sensitivity of the reverse osmosis units to both
alkaline and high temperature fluids. Chlorine can damage the presently
available membranes; therefore, the chlorination of water cannot occur
before the reverse osmosis step.
Ultraf iltration. Ultrafiltration utilizes a membrane process similar to
reverse osmosis for the removal of contaminants from -water. Unlike
reverse osmosis, Ultrafiltration is not impeded by osmotic pressure and
|:an be effected at low pressure differences. The molecular weight range
of materials that might be removed by Ultrafiltration is from 500 to
500,000. This would remove such materials as some microorganisms,
starches, gums, proteins, and clays. Ultrafiltration is finding
applications in the food industry in sugar purification, whey desalting,
and fractionation. It can be used as a substitute for thickeners,
clarifiers, and flocculation in waste water treatment. In addition to
removal of the above contaminants from waste water, it can also be
applied to sludge dewatering.
At the present time, because of high capital and operating costs, this
system has not found acceptance in the treatment of waste effluents.
Ultimate Disposal Methods
Percolation and Evaporation Lagoons. The liquid portion of cane sugar
refining wastes can be "completely11 treated in percolation and
evaporation lagoons. These ponds can be sized according to the annual
flow, so that the inflow plus the incidentally added water are equal to
percolation and evaporation losses. There is, theoretically, no surface
outflow in the usual sense.
Biological solids grown in the pond can be a major operating problem.
The soil interstices can become biologically sealed, causing percolation
rates to be greatly diminished. Unless corrective action is taken, the
pond may become largely an evaporation lagoon. To prevent this, annual
scarification and solids removal might be required.
There are two major objections to percolation-evaporation ponds. The
first is that under almost any loading conditions the ponds may turn
septic, with odor problems resulting. Secondly, there is the potential
for long-range damage to aquifers, since objectionable and biologically
resistant organics may be carried into the groundwater by continuous
percolation.
Spray Irrigation. Spray irrigation is another method currently utilized
in the sugar industry for disposal of waste waters. The design of such
systems is rapidly becoming a highly scientific operation. Numerous
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cases of both unsatisfactory results and trouble-free experience have
been encountered with the application of this technology. Such systems
should be designed with a great deal of flexibility to handle unforeseen
problems. The hydraulic and organic characteristics of the soil profile
as well as the rates of waste degradation must be considered in design.
The need to properly balance nutrient loads to ensure adequate
microbiological activity and adequate growth of plants without undue
losses of nutrients to groundwater must be considered. Other important
design considerations include crop management insuring proper crops and
crop sequences and climatic conditions considering evapotranspiration
rates, precipitation, and cold weather operation.
Spray irritation consists essentially of spraying the liquid waste on a"
field at as high a rate and with as little accompanying nuisances or
difficulties of operation as possible, pretreatment of waste water tO|
remove solids may be necessary in order to prevent clogging of the spray!
nozzles* '
Waste water disseminated by spray irrigation percolates through the soil
and the organic matter in the waste undergoes a biological degradation.
The liquid in the waste stream is either stored in the soil or leached
to a groundwater. Approximately 10 percent of the waste flow will be
lost by evapotranspiration (the loss due to evaporation to the
atmosphere through the leaves of plants).
Spray irrigation presents an ideal method for disposal of liquid wastes
when a combination of suitable features exists. These features include:
A large area of relatively flat land available at an economical
price.
Proximity of the disposal area to the plant site.
Proper type of soil to promote optimum infiltration.
— Absence of a groundwater underlying or nearby the disposal area
which is being or could be used as a public water supply.
— Absence of suspended matter in the waste water of such a nature
as to cause clogging of the spray nozzles.
— Proper combination of climatic conditions conducive to cover
crop growth, percolation and evaporation, i.e., sunny and
relatively dry climate.
In actual practice, waste waters (after adequate screening) are usually
retained in a "surge tank" of sufficient volume to provide continuous
operation of sprays. The impounded screened waste is pumped to a header
pipe and to a series of lateral aluminum or lightweight lines under
ample pressure to provide each sprinkler with similar volumes of waste
water for application to the land.
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The amount, of waste water reaching groundwater is variable in quantity
and rather difficult to predict. In some cases it might be expected
that no usable groundwater would be involved. Considerable study seems
to be needed in evaluating this potential problem.
The following factors must be evaluated in designing a land disposal
system:
— The site should be relatively level and well covered with
vegetation.
— The soil should be light in texture and have a high sand or
gravel content. Some organic matter may be beneficial, but high
clay content is detrimental.
— Spray testing and soil analysis prior to full-scale irrigation
is recommended.
— Soil cultivation should be practiced to prevent compaction.
— Ground water levels at the spray site should be at least 10 feet
below the surface to allow for proper decomposition of the waste
as well as for more rapid percolation.
With the proper equipment and controlled application of the waste, spray
irrigation will completely prevent stream pollution, will not create
odor problems, and is usually less expensive than other methods of waste
disposal. The amount of land required may not, at present, be reliably
predetermined. Different cover crops and different types of soil will
give varying infiltration rates.
Ultimate disposal systems may consist of a combination of lagooning and
land disposal. In this type of system large ponds are constructed to
receive the waste effluents. If odor becomes a problem because of
location, sufficient aeration equipment must be provided to reduce or
eliminate the odor. The waste effluent is removed from the pond or
lagoon and directed to spray irrigation.
Soil fertility, crop production, and soil conservation considerations
must of necessity be used as an ultimate basis for regulating land-
spreading operations if the system is to remain continuously effective.
TREATMENT AND DISPOSAL TECHNOLOGY CURRENTLY EMPLOYED BY THE
REFINING INDUSTRY "" *
CANE SUGAR
Waste water treatment and disposal in the cane sugar refining industry
ranges from essentially no treatment to complete land retention with no
discharge of waste water to surface waters. Since the early 1950's most
large urban refineries have discharged major process waste streams, such
as char wash, to municipal sewers. The current standard practice for
urban refineries, which represent approximately three-fourths of
American refined cane sugar production, is to discharge all waste
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streams other than barometric condenser cooling water to municipal
sewage treatment plants. Rural refineries, representing the remaining
one-fourth of total sugar production, generally have available land for
impoundment, and the standard practice of these refineries is either
total or partial waste water retention.
There are two notable exceptions to the general practice of urban
refineries discharging process water to municipal sewers and barometric
condenser cooling water to surface water bodies. One large crystalline
refinery, which utilizes a cooling tower for recirculation of barometric
condenser cooling water, discharges all waste water except
uncontaminated (non-contact) cooling water to municipal treatment. This
is possible through the use of a cooling tower recycle system which
reduces barometric condenser cooling water discharge by 98 percent
(ultimately this system is expected to reduce the discharge of
barometric condenser cooling water by 99 percent).
The second exception is a small liquid refinery which uses municipal
water for barometric condenser cooling water intake. Unlike other
refineries that use low quality surface water for barometric condenser
cooling water, this refinery is able to extensively re-use the
barometric condenser cooling water effluent in-plant, and discharges all
waste water to municipal treatment. It must be noted, however, that
this refinery does not employ affination, does not have vacuum pans,
and, therefore, uses an atypically small flow of barometric condenser
cooling water.
The following table. Table 17, is a summary of the existing waste
treatment practices of the refineries currently operating. All cane
sugar refineries are represented and the most reliable and current
information presented.
Biological treatment of sugar wastes has been demonstrated to a limited
extent in the raw cane sugar industry and more extensively outside of
the industry. Sucrose is well known to be highly biodegradable, and
substantial BODji reductions have been observed in impoundage lagoons for
treatment of waste waters from combined factory-refineries. In the beet
sugar industry, anaerobic and aerobic fermentation processes have been
successfully used (17). The applicability of biological treatment to
refinery waste waters has also been well demonstrated by the 12
refineries that discharge process wastes to municipal biological
treatment systems. While no refineries currently employ biological
treatment in the form of activated sludge or aerated lagoons, these
systems are considered to be currently available technology for the
industry. With proper design and with nutrient addition to the nutrient
deficient wastes, these systems can achieve 90 to 95 percent and higher
treatment efficiencies for highly organic wastes such as process waste
water from cane sugar refining.
Waste holding lagoons have widespread use in the raw cane sugar industry
and are employed by several cane sugar refineries in rural areas. One
small liquid refinery was at one time operated in conjunction with a raw
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TABLE 17
SUMMARY OF WASTE WATER TREATMENT
AND DISPOSAL TECHNIQUES OF UNITED STATES
CANE SUGAR REFINERIES
Refinery Disposal oj_ Waste Waters
C-l All process water to municipal sewers;
barometric condenser cooling water to
river. Dry haul filter cake after
regeneration and recycle of filter aid.
C-2 All process water to municipal sewers;
barometric condenser cooling water to
river. Dry haul filter cake after
regeneration and recycle of filter aid.
C-3 All liquid wastes to river. Filter
slurry to river.
C-4 All process water to municipal sewers;
barometric condenser cooling water to
river. Dry haul filter cake after
regeneration and recycle of filter aid.
C-5 All process water to municipal sewers;
barometric condenser cooling water to
river. Dry haul filter cake.
C-6 All liquid wastes to river. Dry haul
filter cake. Future use of municipal
system is probable.
C-7 Primary settling of process water;
overflow discharges to river.
C-8 All liquid wastes to river. Future
use of municipal system is probable
(sewer hook-up is in-place). Dry haul
filter cake.
C-9 Most process water to municipal sewers;
barometric condenser cooling water to
river. Dry haul filter cake.
C-10 Most process water to municipal sewers;
barometric condenser cooling water to
river. Dry haul filter cake.
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TABLE 17
SUMMARY OF WASTE WATER TREATMENT
AND DISPOSAL TECHNIQUES OF UNITED STATES
CANE SUGAR REFINERIES
(CONTINUED)
Refinery Disposal of Waste Waters
C-ll Discharge into a swamp after traveling
through a two and a half mile canal.
Have recently constructed a spray pond.
Recycle of barometric condenser cooling
water is a possibility.
C-12 Total impoundment of waste water
resulting in no discharge to navigable
waters. Have two cooling towers for
recycle of barometric condenser cooling
waters; blowdowns are .3 and .7 percent.
C-13 Discharges into a swamp.
C-14 All process wastes to municipal sewers;
recycle of barometric condenser cooling
water through a cooling tower and
discharge of blowdown to municipal sewers
Dry haul filter cake.
L-l All liquid wastes to municipal sewers.
Filter slurry to municipal sewer.
L-2 All process water to municipal sewer;
barometric condenser cooling water to
river. Filter slurry to settling,
dewatering, and dry haul.
L-3 All process water to municipal sewer;
barometric condenser cooling water to
river. Filter slurry to sewer.
L-4 ' Total impoundment of waste waters
resulting in no discharge to navigable
waters. Barometric condenser cooling
water recycled through a spray canal.
Filter slurry to total impoundage.
L-5 Barometric condenser cooling water
recycled through a cooling tower.
Process water and filter slurry
discharged with no treatment.
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TABLE 17
SUMMARY OF WASTE WATER TREATMENT
AND DISPOSAL TECHNIQUES OF UNITED STATES
CANE SUGAR REFINERIES
(CONTINUED)
Refinery Disposal of Waste Waters
CL-1 Most process water to municipal sewers;
barometric condenser cooling water to
river. Filter slurry dewatered and
dry hauled.
CL-2 Most of process wastes to municipal
sewers; barometric condenser cooling
water to river. Dry haul filter cake.
CF-1 Closed system of canals and holding
ponds resulting in no discharge to
navigable waters. Filter slurry to
total impoundage. Barometric condenser
cooling water recycled through a spray
pond.
CF-2 Total impoundment of acid/caustic wastes
and filter cake slurry; impoundment
with overflow of all other waste waters,
700 acres of lagoons.
CF-3 Barometric condenser cooling water passed
through spray pond (partial recycle,
75-90%, possible) before discharge; all
process waters discharge to total im-
poundage. Filter slurry to total im-
poundage .
CF-4 Barometric condenser cooling impounded,
then discharged; all other waters im-
pounded completely in ponds; cooling
tower recently built (50% of condenser
water); recycle possible. Filter
slurry to total impoundage.
CF-5 Partial impoundment.
CF-6 Partial reuse of waste waters in raw
sugar factory for cane washing during
grinding season.
CF-7 Partial impoundment.
CF-8 Partial impoundment.
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sugar factory, and a lagoon system was designed to contain all wastes
from both operations. The subsequent closing of the factory left the
refinery with more than adequate pond area for total:''.-waste water
impoundage. Several factory-refinery combinations in Louisiana,
Florida, and Puerto Rico use impoundage to various extents; two
refineries discharge to large, swampy, private land holdings with a
resulting undefined eventual discharge.
Those refineries which utilize waste holding ponds to achieve impoundage
with an overflow are those operating in conjunction with raw cane sugar
factories. Wastes from both the refinery and the factory are-discharged
to the same holding ponds, making it impossible to determine the treat-
ment efficiency associated with the application of this technology to
refinery waste waters alone.
In the construction and operation of holding ponds, sealing of pond
bottoms to control percolation may be necessary (although expensive),
but self sealing may occur as a result of organic mat formation. No
contamination of groundwater should be allowed.
Land irrigation is practiced at only one refinery - a small refinery in
Puerto Rico which is located on the dry south coast of the island.
Other refineries are prohibited from using this technology by either (1)
being located in urban areas, or (2) being located in areas of high
rainfall.
Deep-well injection is not practiced in cane sugar refining nor in beet
sugar processing; one raw cane sugar factory in Florida practices this
method of disposal. peep-well injection may exist as a disposal
alternative; however, the effects of subsurface injection are usually
difficult to determine. This method of disposal can only be recommended
with the stipulation that extensive studies be conducted to insure
environmental protection beyond any reasonable doubt.
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SECTION VIII
COST, ENERGY, AND NON-WATER QUALITY ASPECTS
COST AND REDUCTION BENEFITS OF ALTERNATIVE TREATMENT AND CONTROL
TECHNOLOGIES FOR CANE SUGAR REFINERIES
The Model Refineries
Assumptions Pertaining to Water Usage, Raw Waste
Alternatives of Control and Treatment
Loading, and
For the purpose of establishing effluent limitations guidelines, model
refineries were hypothesized to represent the crystalline and liquid
cane sugar refining industry subcategories. These model refineries were
derived from a basis of average water usage and conservation, but
average to poor in-plant controls to limit BOD5 and suspended solids
loadings. These model refineries are illustrated in Figures 18 and 19.
The following treatment alternatives have been applied to these model
refineries to determine the best practicable control technology
currently available (BPCTCA) , the best available technology economically
achievable (BATEA) , and the standards of performance for new sources
(NSPS):
Alternative As This Alternative represents the baseline
and includes good water usage but poor in-plant controls.
This Alternative also assumes no treatment, and represents
the model raw waste loadings.
Alternative B; This Alternative involves the elimination
of a discharge of filter cake, which results from the
clarification of melt liquor. Filter cake can be disposed
of without discharge to navigable waters by controlled
impoundage of the filter slurry (Alternative B-l) or by
dry handling of the filter cake (Alternative B-2). A
decrease in water usage of 0.25 cubic meters per metric
ton (60 gallons per tons) of melt is evidenced over
Alternative A if dry handling of filter cake is in-
corporated.
Alternative C; This Alternative involves, in addition
to Alternative B, the addition of demisters and external
separators to reduce entrainment of sucrose into baro-
metric condenser cooling water. This technology is
illustrated for both liquid and crystalline refineries
in Figures 20 and 21. For the barometric condenser
cooling water flows developed for both the crystalline
and liquid cane sugar refining subcategories, BOD5 entrain-
ment can be reduced to below 10 mg/1* *"
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Barometric Condenser
Cooling Water
BOD, 0.56 kg/kkg
(ITU. Ib/ton)
5' n ~d
Flow:
33.9
(8150 gal/ton)
Process Water
BOD5 0.82 kg/kkg (1,64 Ib/ton)
TSS 1.30 kg/kkg (2.60 Ib/ton)
Filter Cake Slurry
BOD5 0.475 kg/kkg(0.95 Ib/ton)
TSS 7.9 kg/kkg (15.80 Ib/ton)
Flow:
Flow:
0.25
(60 gal/ton)
35.6 m3/kkg
(8560 gal/ton)
Discharge
BOD5 1.85 kg/kkg(3.70 Ib/ton)
TSS 9.20 kg/kkg (18.4 Ib/ton)
Flow:
1.46 nrYkkg
(350 gal/ton)
Figure 18
ESTIMATED RAW WASTE LOADINGS AND WATER USAGE
FOR THE MODEL CRYSTALLINE CANE SUGAR REFINERY
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Barometric Condenser
Cooling Water
BODr 0.50 kg/kkg
(1TOO Ib/ton)
Flow:
15.0 m3/kkg
(3600 gal/ton)
10
Process Water
BOD5 2.75 kg/kkg (5.50 Ib/ton)
TSS 1.00 kg/kkg (2.00 Ib/ton)
Filter Cake Slurry
BOD5 0.475 kg/kkg(0.95 Ib/ton)
TSS 7.90 kg/kkg (15.80 Ib/ton)
Flow:
Flow:
0.25 m3/kkg
(60 gal/ton)
16.9 m3/kkg
(4050 gal/ton)
Discharge
BOD5 3.725 kg/kkg(7.45 Ib/ton)
TSS 8.90 kg/kkg (17.80 Ib/ton)
Flow:
1.64 m3/kkg
(393 gal/ton)
Figure 19
ESTIMATED RAW WASTE LOADINGS AND WATER USAGE
FOR THE MODEL LIQUID CANE SUGAR REFINERY
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CRYSTALLINE REFINERIES
Average
Condenser Water
BOD5o.44 kg/kkg
(0.88 lb/ton)
Flow:
36.5 m3/kkg
(8750 gal/ton)
Model
Condenser Water
BOD50.56 kg/kkg
(1.11 lb/ton)
(Model)
Flow:
33.9 m3/kkg
(8150 gal/ton)
Model
Condenser Water
BOD50.34 kg/kkg
(0.68 lb/ton)
(Alternative C)
10 **"*'J
Flow:
33.9 m3/kkg
(8150 gal/ton)
Figure 20
CONDENSER WATER LOADINGS AND WATER USAGE FOR
CRYSTALLINE CANE SUGAR REFINERIES
LIQUID REFINERIES
Average
Condenser Water
BODg 0.31 kg/kkg
(0.62 lb/ton)
Flow:
16.3m3/kkg
(3900 gal/ton)
Model
Condenser Water
BODS 0.50 kg/kkg
(1.00 lb/ton)
(Model)
93.3 ^J/
Flow:
15.0
(3600 gal/ton)
Model
Condenser Water
BOD5 0.15 kg/kkg
(0.30 lb/ton)
(Alternative C)
Flow:
15.0 m3/kkg
{3600 gal/ton)
Figure 21
CONDENSER WATER LOADINGS AND WATER USAGE FOR
LIQUID CANE SUGAR REFINERIES
ins
-------
Alternative D; This Alternative involves, in addition
to Alternative C, the addition of an activated sludge
system to treat process waters.
Alternative E: This Alternative involves, in addition
to Alternative D, the recycle of barometric condenser
cooling water through a cooling device with biological
treatment of the assumed two percent blowdown and in-
corporates sand filteration of the effluent from the
activated, sludge system to further effect solids removal.
This results in reductions in water usages of 88 percent
for liquid refineries and 94 percent for crystalline
refineries, over Alternative D.
Alternative F; This Alternative includes, in addition
to Alternative C, the elimination of a discharge of
process waters by total impoundage of this waste stream.
This technology requires that large quantities of land
be available and is not judged to be available technology
for urban refineries. It is a current practice of many
rural refineries, however.
Alternative G: This Alternative involves in addition
to Alternative F, a recycling of barometric condenser
cooling water through a cooling device and total re-
tention of the assumed two percent blowdown. This
technology requires that large quantities of land be
available and is not judged to be available technology
for urban refineries. It is a current practice of
three refineries, all rurally located. Reduction in
water usages of 88 percent for liquid refineries and
94 percent for crystalline refineries results, over
Alternative F.
Assumptions Pertaining to the Cost of Control and Treatment Alternatives
The cost estimates contained in this document are based on two
crystalline refineries with melts of 545 metric tons (600 tons) per day
and 1900 metric tons (2100 tons) per day, respectively, and a liquid
refinery with a melt of 508 metric tons (560 tons) per day. These
refineries are considered to be generally representative of both large
and small crystalline operations and of liquid operations. Obviously,
any given existing installation may vary considerably from the models
presented; each sugar refinery has unique characteristics and unique
problems that must be taken into consideration. The following are
assumed features of the representative refineries:
1. The present level of barometric condenser cooling water
BOD5 entrainment is 16 ppm in crystalline refineries
and 33 ppm in liquid refineries.
2. Both liquid and crystalline refineries employ liquid level
controls on evaporators and absolute pressure controls on
the last evaporator body.
107
-------
3. Both crystalline refineries employ triple-effect evapora-
tors; the liquid refinery uses double-effect evaporators.
4. Total mud slurry equals 114 cubic meters (30,000 gallons)
per day for the liquid refinery, 135 cubic meters (35,700
gallons) per day for the 545 metric ton (600 ton) per day
crystalline refinery, and 455 cubic meters (120,000 gallons)
per day for the 1900 metric ton (2100 ton) per day crystal-
line refinery.
5. The operating year consists of 250 days.
6. Ninety-eight percent of condenser water BOD5_ is due to
sucrose.
7. Both liquid and crystalline refineries discharge dia-
tomaceous earth filter slurries.
8. The liquid and crystalline refineries do not recycle
condenser water.
9. There is presently a discharge of process water with no
treatment in the case of both liquid and crystalline
refineries.
Basis^of Cost Analysis
The following are the basic assumptions made in the presentation of cost
information:
1. Investment costs are based on actual engineering cost
estimates.
2. 0.454 kg (one lb.) of sugar is equivalent to .511 kg
(1.125 lb.) of BOD5.
3. 3.79 liters (one gallon) of 80° Brix final molasses
sells for $.042 per liter ($.16 per gallon).
4. All costs are August 1971 dollars.
5. Equipment depreciation is based on an 18 year straight-
line method, except for rolling stock which is depre-
ciated over 6 years by the straight-line method.
6. Excavation of filter mud pits costs $0.53 per cubic meter
($.40 per cubic yard); annual excavation and disposal
costs $0.79 per cubic meter ($0.60 per cubic yard).
7. Annual interest rate for capital cost equals 8 percent.
8. Salvage value for all facilities depreciated over 18
years is zero.
9. Only sugar losses in the barometric condenser cooling
water can be recovered.
10. Liquid sugar sells for $254.00 per metric ton ($230.50
per ton); crystalline sugar sells for $260.00 per metric
ton ($236.40 per ton).
11. Contingency is taken at 10 percent of installed cost.
12. Engineering and expediting costs are taken at 10 percent
of installed cost plus contingency.
13. Total yearly cost equals:
(Investment cost) . (Yearly depreciation percentage) +
Yearly operating cost + (Investment cost /2) (.08)
108
-------
14. Hook-up charges associated with disposal to municipal
systems are assumed to be zero.
Qualifying Statements. The following cost analyses include in some
cases considerable costs for excavation and dyke construction. In some
instances these cdsts may be minimized or nullified by topographic
conditions. In other instances they may be reduced by utilizing in-
house equipment and labor.
Land costs vary widely. The figures used herein are considered to be
representative of non-urban areas where the use of land would be
expected. In urban areas land is often not available; when it is used,
the cost can be expected to be substantially higher than reported in
this document.
The investment cost associated with hook-up to a municipal waste system
is assumed herein to be nil. In actuality this cost can vary from zero
to considerable sums of money; for purposes of economic impact^ it is
necessary to assess the cost on an individual basis. However, for the
purpose of presenting cost information for the cane sugar refining
industry, it must be noted that thirteen refineries already have
municipal hook-up. Therefore, for these thirteen refineries, the
assumption of zero additional cost is valid because they already have
municipal hook-up.
Crystalline Refining
Two representative crystalline refineries were chosen as a basis for
cost estimates: a small refinery with a melt of 545 metric tons (600
tons) per day and a large refinery with a melt of 1900 metric tons (2100
tons) per day. The following treatment alternatives may be applied to
both refineries.
Alternative A; No Waste Treatment or Control.. The effluent from a 545
metric ton (600 ton) per day crystalline refinery is 19,900 cubic meters
(5.14 million gallons) per day and from a 1900 metric ton (2100 tons)
per day crystalline refinery is 68,00 0 cubic meters (18.0 million
gallons') per day. The resulting BOD5 and suspended solids loads are
1.85 kilograms per metric ton (3.70 pounds per ton) and 9.20 kilograms
per metric ton (18.40 pounds per ton) respectively, for both refineries.
Since no waste treatment is involved, no cost associated with waste
treatment or control can be attributed to this Alternative.
COSTS: 0
REDUCTION BENEFITS: None
Alternative B: Elimination of Discharge from Filters. This Alternative
can be achieved either by impounding the mud resulting from slurrying
filter cake with water or by dry hauling the desweetened filter cake to
landfill. The resulting effluent waste loads for BOD5 and suspended
solids are 1.375 kilograms per metric ton (2.75 pounds per ton) of melt
109
-------
and 1.30 kilograms per metric ton (2.60 pounds per ton) of rue It
respectively, at this control level.
B-l: Impound Filter Slurry
COSTS: 545 metric tons (600 tons) per day crystalline refinery
Incremental Investment Cost: $33,000
Total Investment cost: $33,000
Total Yearly Cost: $ 8,600
1900 metric tons (2100 tons) per day crystalline refinery
Incremental Investment cost: $66,000
Total Investment Cost: $66,000
Total Yearly Cost: $20,000
B-2: Dry Disposal of Filter Cake
COSTS: 545 metric tons (600 tons) per day crystalline refinery
Incremental Investment cost: $61,000
Total Investment Cost: $61,000
Total Yearly Cost: $45,000
1900 metric tons (2100 tons) per day crystalline refinery
Incremental investment cost: $61,000
Total Investment Cost: $61,000
Total Yearly Cost: $71,000
REDUCTION BENEFITS:
An incremental reduction in BOD5 of approximately 0.475
kilograms per metric ton (0.95 pounds per ton) of melt
and in suspended solids of approximately 7.9 kilograms
per metric ton (15.8 pounds per ton) of melt is evi-
denced over Alternative A. Total plant reductions of
25.7 percent for BOD5 and 85.9 percent for suspended
solids would be achieved.
For the purpose of accruing total costs in this
section of the report, the use of dry disposal of
filter cake (B-2) will be considered representative
of Alternative B.
Alternative Ci In plant Modifications to Reduce Entrainment of Sucrgs e
into condenser water. This Alternative includes, in addition to
Alternative B, the installation of demisters and external separators in
order to reduce entrainment of sucrose in barometric condenser cooling
water. It is assumed that, in addition, both refineries have good
baffling and operational controls in the evaporators and vacuum pans, as
well as good vapor height. This technology is currently widely
practiced in the industry. The resulting effluent waste loads for BOD5
no
-------
and suspended solids are 1.16 kilograms per metric ton (2.32 pounds per
ton) of melt and 1.30 kilograms per metric ton (2.60 pounds per ton) of
melt respectively, for the selected refineries at this control level.
COSTS; 545 metric tons (600 tons) per day crystalline refinery
Incremental Investment Cost: $ 52,000
Total Investment Cost: $113,000
Total Yearly Cost: $ 62,000
1900 metric tons (2100 tons) per day crystalline refinery
Incremental Investment Cost: $ 73,000
Total Investment Cost: $134,000
Total yearly Cost: $ 75,000
REDUCTION BENEFITS: An incremental reduction in BOD5 of 0.22 kilograms
per metric ton (0.44 pounds per ton) of melt is
evidenced over Alternative B. The total reduction
in BOD5 is 37.3 percent. No further reduction in
suspended solids is achieved.
Alternative Q: Biological Treatment of Process Water. This Alternative
assumes the addition of an activated sludge plant to Alternative C to
treat process water. Presently there are no refineries which have their
own biological treatment systems, but refinery wastes are commonly
treated in municipal biological treatment plants. As discussed in
Section VTI, Contrgl and Treatment Techrigj.ggY, refinery waste water is
highly biodegradable and thus well suited for biological treatment,
A schematic of the activated sludge system is shown in Figure 22. Waste
water is pumped through a primary clarifier to an aerated lagoon, with
biological sludge being returned to the aerated lagoon from a secondary
clarifier. Excess sludge is pumped to a sludge digester; the sludge
from the digester is pumped to a holding lagoon. The total effluent
waste loadings as a . result of the addition of this Alternative are
estimated to be 0.43 kilograms per metric ton (0.86 pounds per ton) of
melt for BOD5 and 0.09 kilograms per metric ton (0.18 pounds per ton) of
melt for suspended solids.
COSTS: 545 metric tons (600 tons) per day crystalline refinery
Incremental Investment Cost: $255,000
Total Investment Cost: $368,000
Total Yearly cost: $205,000
1900 metric tons (2100 tons) per day crystalline refinery
Incremental Investment Cost: $662,000
Total Investment Cost: $796,000
Total yearly Cost: $296,000
111
-------
HOLDING LAGOON
SLUDGE DIGESTER
FIGURE 22
SCHEMATIC OF ACTIVATED SLUDGE SYSTEM
-------
REDUCTION BENEFITS: An incremental reduction in BOD5. of approximately
0.73 kilograms per metric ton (1.46 pounds per
ton) of melt and in suspended solids of approx-
imately 1.21 kilograms per metric ton (2.42 pounds
per ton) of melt is evidenced over Alternative C.
Total reductions of 76.8 percent for BODjj and 99.0
percent for suspended solids would be achieved.
Alternative E^ Recycle of Condenser Water and Biological Treatment of
Slowdown. This Alternative includes, in addition to Alternative D, the
recycle of barometric condenser cooling water followed by biological
treatment of the blowdown in an activated sludge unit and the addition
of gand filtration to further treat the effluent from the activated
sludge unit.The blowdown is assumed to be approximately two percent of
the barometric condenser cooling water flow. Presently, there are three
refineries using cooling towers and two which utilize a spray pond for
the purpose of recycling barometric condenser cooling water. Recycle of
barometric condenser cooling water accomplishes two important things;
(1) it cools the water, thereby removing the heat normally discharged
and (2) it concentrates the waste loadings into the smaller blowdown
stream, making biological treatment of this waste stream feasible. The
total effluent waste loadings as a result of the addition of this
Alternative are estimated to be 0.09 kilograms per metric ton (0.18
pounds per ton) of melt for BOD5 and 0.035 kilograms per metric ton
(0.07 pounds per ton) of melt for" suspended solids. In addition,
665,000 kilogram calories per metric ton (2.4 million BTU per ton) of
melt are effectively removed from barometric condenser cooling water.
Under the most adverse conditions (lack of available land with no
suitable alternative, excessive drift, fogging, noise, or a combination
of these factors), which are presently not anticipated, the costs of
application of this technology (cooling devices) could in some instances
result in significant cost increases.
There are a number of methods of recycling barometric condenser cooling
water; for the purposes of this document, the following are considered:
cooling towers and spray ponds.
E-l: Alternative E with a Cooling Tower
COSTS: 545 metric tons (600 tons) per day crystalline refinery
Incremental investment Cost: $346,000
Total Investment Cost: $714,000
- Total Yearly Cost: $283,000
1900.metric tons (2100 tons) per day crystalline refinery
Incremental Investment Cost: $ 714,000
Total Investment Cost: $1,510,000
Total Yearly Cost: $ 470,000
113
I
-------
E-2: Alternative E with a spray Pond
COSTS: 545 metric tons (600 tons) per day crystalline refinery
Incremental Investment Cost: $ 282,000
Total Investment. Cost: $ 650,000
Total Yearly Cost; $ 271,000
1900 metric tons (2100 tons) per day crystalline refinery
Incremental Investment Cost: $ 596,000
Total Investment Cost: $1,392,000
Total Yearly Cost: $ 438,000
REDUCTION BENEFITS: An incremental reduction in BOD5 of approximately
0.34 kilograms per metric ton (0.68 pounds per ton)
of melt and in suspended solids of 0.055 kilograms
per metric ton (0.11 pounds per ton) of melt
is evidenced by addition of this Alternative
to Alternative D, Total reductions of 95.1 percent
for BOD5_ and 99.6 percent for suspended solids would
be achieved.
Alternative F: Elimination of Discharge of Process Water. This
Alternative assumes that, in addition to Alternative C, all process
waters are eliminated by controlled retention and total impoundage. The
resulting effluent waste loading for BOD5 associated with this control
level is estimated at 0.34 kilograms per metric ton (0.68 pounds per
ton) of melt, that amount attributable to barometric condenser cooling
water. The suspended solids loading is zero as the only suspended
solids-bearing waste stream has been eliminated.
F: Elimination of Discharge of Process Water
by containment
Total impoundment of process water is sucessfully practiced by five
refineries; however, a considerable amount of land is required (see
Tables 17 and 18, Path 13). Containment of process waters is,
therefore, not considered to be practicable technology for urban
crystalline refineries.
COSTS: 545 metric tons (600 tons) per day crystalline refinery.
Incremental Investment Cost: $1,410,000
Total Investment Cost: $1,530,000
Total Yearly Cost: $ 211,000
1900 metric tons (2100 tons) per day crystalline refinery
Incremental Investment Cost: $4,870,000
114
-------
Total Investment Cost
Total Yearly Cost:
$5,000,000
$ 59; ,,000
REDUCTION BENEFITS: An incremental reduction in plant BGD5 of 0.82 kilograms
per metric ton (1.64 pounds per ton) of melt and in
suspended solids of 1.30 kilograms per metric ton (2.60
pounds per ton) of melt is evidenced in comparison to
Alternative c. Total reductions in BOD5 of 81.6 percent
and in suspended solids of 100 percent are achieved.
Alternative Gg gliminatign of Discharge of Barometric Condenser Cooling
Water. This Alternative assumes that in addition to Alternative F,
there is an elimination of discharge of barometric condenser cooling
water. To achieve this level of treatment, it has been assumed that
barometric condenser cooling water is recycled and the blowdown
impounded. The blowdown of barometric condenser cooling water is
assumed to be two percent of the total condenser flow. Effluent waste
loadings associated with this control level are zero kilograms per
metric ton (zero pounds per ton) of melt.
G-l: Recycle of condenser Water Through a Cooling Tower
with an Assumed Two Percent Blowdown to Controlled
Land Retention, in Addition to Alternative F.
COSTS: 545 metric tons (600 tons) per day crystalline refinery
Incremental Investment Cost: $1,000,000
Total Investment Cost: $2,530,000
Total Yearly cost: $ 352,000
1900 metric tons (2100 tons) per day crystalline refinery
Incremental Investment Cost; $2,620,000
Total Investment Cost: $7,620,000
Total Yearly Cost: $ 950,000
G-2: Recycle of Condenser Water Through a Spray Pond
with an Assumed Two Percent Blowdown to Controlled
Land Retention, in Addition to Alternative F.
COSTS: 545 metric tons (600 tons) per day crystalline refinery
Incremental Investment Cost; $ 940,000
Total Investment Cost: $2,470,000
Total Yearly cost: $ 340,000
1900 metric tons (2100 tons) per day crystalline refinery
Incremental Investment Cost: $2,510,000
Total Investment Cost: $7,510,000
Total Yearly Cost: $ 918,000
115
-------
TABLE 18
SUMMARY OF WASTE LOADS FROM TREATMENT ALTERNATIVES
FOR THE SELECTED CRYSTALLINE REFINERIES
CTt
Effluent
Constituent Raw
Parameters Waste
BOD5 kg/kkg of melt 1.85
(Ib/ton of melt) (3.70)
TSS kg/kkg of melt 9.20
(Ib/ton of melt) (18.40)
DISCHARGE FLOW (m3/kkg)
Barometric Condensers 33.9
Process Water 1.46
Filter Slurry 0.25
Treatment
A
1.
(3.
9.
(18.
33.
1.
0.
85
70)
20
40)
9
46
25
B
1.
(2.
1.
(2.
33.
1,
0
375
75)
30
60)
9
46
1
(2
1
(2
33
1
C
.16
.32)
.30
.60)
.9
.46
0
Alternative
D*
0.43
(0.86)
0.09
(0.18)
33.9
1.46
0
0
(0
0
(0
0
1
E**
.09
.18)
.035
.07)
.68
.46
0
F
0.34
(0.68)
0
(0)
33.9
1.46
0
G
0
(0)
0
(0)
0.68
1.46
0
* BPCTCA
** BATEA;NSPS
-------
TABLE 19
SUMMARY OF ALTERNATIVE COSTS FOR A 545 METKIC TONS
(600 TONS) PER DAY CRYSTALLINE SUGAR REFINERY
Total
Alternative
A
B-1
B-2
C
D
E-l
E-2
F
6-1
G-2
BOD5
Load*
1.85
1.375
1.375
1.16
0.43
0.09
0.09
0.34
0.0
0.0
% BOD5.
Removal
0.0
25.6
25.6
37.3
76.8
95.1
95.1
81.6
100
100
TSS
Load*
9.20
1.30
1.30
1.30
0.09
0.035
0.035
0.0
0.0
0.0
% TSS
Removal
0.0
85.9
85.9
85.9
99.0
99.6
99.6
100
100
100
Investment
Cost
0
33,000
61 ,000
113,000
368,000
714,000
650,000
1,530,000
2,530,000
2,470,000
Yearly
Operating
Cost
0
5,400
36,700
55,600
174,000
219,000
214,000
70,000
114,000
109,000
Total
Yearly
Cost
0
8,600
45,000
62,000**
205,000
283,000
271,000
211,000
352,000
340,000
*Waste Loadings in Kilograms per Metric Ton of Melt
**Includes Sugar Savings of $7,400/yr. as a Result
of Entrainment Prevention.
117
-------
TABLE 20
SUMMARY OF ALTERNATIVE COSTS FOR A 1,900 METRIC TONS
(2,100 TONS) PER DAY CRYSTALLINE SUGAR REFINERY
Alternative
Total
Yearly Total
^ % BOD5_ TSS % TSS Investment Operating Yearly
Load* Removal Load* Removal Cost Cost Cost
A
B-l
B-2
C
D
E-l
E-2
F
G-l
G-2
1
1
1
1
0
0
0
0
0
0
.85
.375
.375
.16
.43
.09
.09
.34
.0
.0
0.0
25.6
25.6
37.3
76.8
95.1
95.1
81.6
100
100
9.20
1.30
1.30
1.30
0.09
0.035
0.035
0.0
0.0
0.0
0.0
85.9
85.9
85.9
99.0
99.6
99.6
100
100
100
0
66
61
134
796
1,510
1,390
5,000
7,620
7,510
,000
,000
,000
,000
,000
,000
,000
,000
,000
14
64
87
244
350
330
137
245
226
0
sooo
,000
,000
,000
,000
,000
,000
,000
,000
0
20
71
75
296
470
438
591
950
918
,000
,000
,000**
,000
,000
,000
.000
,000
,000
*Waste Loadings in Kilograms per Melt
**Includes Sugar Savings of $27,000/yr. as a
Result of Entrainment Prevention.
118
-------
TABLE 21
IMPLEMENTATION SCHEDULES FOR A SMALL CRYSTALLINE SUGAR REFINERY
Path
Description
of Path
BOD
Loading
Discharged
kg/kkg
Heat
Loading
Discharged
k-Cal/kkg
Hectares of
Available Municipal
Land Sewer
Required Required
Investment
Cost
Total Yearly
Costs
Including
Power
1 Containment of filter
muds, all process
water, and blowdown
from cooling tower
61
No
2,500,000
316,000
Containment of filter
muds, alI process
water, and blowdown
from spray pond
Containment of filter
muds and discharge
process water and
blowdown from cooling
tower to municipal
treatment
Containment of filter
muds and discharge of
process water and
blowdown from spray
pond to municipal
treatment
Dry disposal of filter
cake and containment
of all process waters
and blowdown from
cooling tower
61
No
0.7
Yes
0.7
Yes
60
No
2,440,000 304,000
297,000 113,000
233,000 102,000
2,530,000 352,000
-------
TABLE 21
IMPLEMENTATION SCHEDULES FOR A SMALL CRYSTALLINE SUGAR REFINERY
Path
Description
of Path
(Continued)
BOD Heat Hectares of
Loading Loading Available Municipal
Discharged Discharged Land Sewer
kg/kkg k-Cal/kkg Required Required
Total Yearly
Costs
Investment Including
Cost Power
Dry disposal of filter
cake and containment of
all process water and
blowdown from spray
pond
Dry disposal of filter
cake with discharge of
process waters and
blowdown from cooling
tower to municipal
treatment
Dry disposal of filter
cake and containment
of all process water and
blowdown from spray pond
to municipal treatment
Containment of filter
muds and biological
treatment of process
water and blowdown
from cooling towers, fol-
lowed by sand filtr.
Containment of filter
muds and biological
treatment of process
water and blowdown
from spray pond, fol-
lowed by sand filtr.
60
No
2,470,000 340,000
0.2
Yes
325,000 149,000
0.2
Yes
261,000
138,000
0.09
0.8
No
686,000
247,000
0.09
0.9
No
622,000
235,000
-------
TABLE 21
Path
IMPLEMENTATION SCHEDULES FOR A SMALL CRYSTALLINE SUGAR REFINERY
(Continued)
BOD Heat Hectares of Total Yearly
Loading Loading Available Municipal Costs
Description Discharged Discharged Land Sewer Investment Including
of Path kg/kkg k-Cal/kkg Required Required Cost Power
11 Dry disposal of filter
cake and biological
treatment of process
water and blowdown
from cooling tower, fol-
lowed by sand filtr. 0.09
12 Dry disposal of filter
cake and biological
treatment of process
water and blowdown
from spray pond, fol-
lowed by sand filtr. 0.09
13 Containment of filter
muds and process waters
and discharge of con-
denser water without
cooling or recycle 0.34
14 Containment of filter
muds, municipal treat-
ment of process waters,
and discharge of con-
denser water without
1 cooling or recycle 0.34
15 Dry disposal of filter
cake, containment of
process water and dis-
charge of condenser
water without cooling
or recycle 0.34
0.3
No
714,000
283,000
0.4
No
650,000
271,000
0.67
38
No
1,500,000 174,000
0.67
0.5
Yes
85,000
53,000
0.67
38
No 1,530,000
211,000
-------
TABLE 21
no
PO
IMPLEMENTATION SCHEDULE FOR A SMALL CRYSTALLINE SUGAR REFINERY
(Continued)
Path
Description
of Path
BOD Heat Hectares of Total Yearly
Loading Loading Available Municipal Costs
Discharged Discharged Land Sewer Investment Including
kg/kkg k-Cal/kkg Required Required Cost Power
16 Dry disposal of filter
cake, municipal treat-
ment of process water,
and discharge of con-
denser water without
cooling or recycle 0.34
17 Containment of filter
muds, biological treat-
ment of process water,
and discharge of con-
denser water without
cooling or recycle 0.43
18 Dry disposal of filter
cake, biological treat-
ment of process water,
and discharge of con-
denser water without
cooling or recycle 0.43
0.67
0.67
0.67
Yes
113,000
89,000
0.7
No
340,000
169,000
0.2
No
368,000
205,000
-------
TABLE 22
ro
CO
IMPLEMENTATION SCHEDULES FOR A LARGE CRYSTALLINE SUGAR REFINERY
Description
Path of Path
BOD
Loading
Discharged
kq/kkg
Heat
Loading
Discharged
k-Cal/kkg
Hectares of
Available
Land
Requi red
Total Yearly
Municipal
Sewer
Required
Investment
Cost
Costs
Including
Power
1 Containment of filter
muds, all process
waters, and blowdown
from cooling tower
Containment of filter
muds, all process
water, and blowdown
from spray pond
Containment of filter
muds and discharge
process water and
blowdown from cooling
tower to municipal
treatment
Containment of filter
muds and discharge of
process water and
blowdown from spray
pond to municipal
treatment
Dry disposal of filter
cake and containment
of all process waters
and blowdown from
cooling tower
198
No
198
No
1.8
Yes
1.9
Yes
196
No
7,620,000
7,510,000
899,000
868,000
539,000
252,000
423,000
221,000
7,620,000
950,000
-------
TABLE 22
Path
IMPLEMENTATION SCHEDULES FOR A LARGE CRYSTALLINE SUGAR REFINERY
(Continued)
BOD Heat Hectares 'of Total Yearly
Loading Loading Available Municipal Costs
Description Discharged Discharged Land Sewer Investment Including
of Path kg/kkg k-Cal/kkg Required Required Cost Power
10
Dry disposal of filter
muds and containment of
all process water and
blowdown from spray
pond
Dry disposal of filter
mud with discharge of
process waters and
blowdown from cooling
tower to municipal
treatment
Dry disposal of filter
cake, containment of
all process water, and
blowdown from spray
pond to municipal
treatment
Containment of filter
muds and biological
treatment of process
water and blowdown
from cooling tower, fol-
lowed by sand ftltr.
Containment of filter
muds and biological
treatment of process
water and blowdown
from spray pond fol-
lowed by sand filtr.
196
No
7,510,000
918,000
0.2
Yes
534,000
303,000
0.2
Yes
418,000
272,000
0.09
1.7
No
1,510,000
419,000
0.09
1.9
No
1,400,000
387,000
-------
TABLE 22
12
ro
tn
13
14
15
IMPLEMENTATION SCHEDULES FOR A LARGE CRYSTALLINE SUGAR REFINERY
~(Continued)
Path
11 D
Description
of Path
ry disposal of
BOD
Loading
Discharged
kg/kkg
filter
Heat
Loading
Discharged
k-Cal/kkq
Hectares of
Avai lable
Land
Required
Municipal
Sewer
Required
Investment
Cost
Total Yearly
Costs
Including
Power
cake and biological
treatment of process
water and blowdown
from cooling tower, fol-
lowed by sand filtr. 0.09
Dry disposal of filter
cake and biological
treatment of process
water and blowdown
from spray pond, fol-
lowed by sand filtr.
Containment of filter
muds and process waters
and discharge of con-
denser water without
cooling or recycle
Containment of filter
muds, municipal treat-
ment of process waters,
and discharge of con-
denser water without
cooling or recycle
Dry disposal of filter
cake, containment of
process water and dis-
charge of condenser
water without cooling
or recycle
0.3
No
1,510,000
470,000
0.09
0.4
No
1,390,000
438,000
0.34
0.67
136
No 5,010,000 540,000
0.34
0.67
1.6
Yes
139,000 120,000
0.34
0.67
135
No 5,000,000 591,000
-------
TABLE 22
IMPLEMENTATION SCHEDULES FOR A LARGE CRYSTALLINE SUGAR REFINERY
(Continued)
Path
Description
of Path
BOD
Loading
Discharged
kg/kkg
Heat
Loading
Discharged
k-Cal/kkg
Hectares of
Available
Land
Required
Municipal
Sewer
Required
Investment
Cost
Total Yearly
Costs
Including
Power
ro
Oi
16 Dry disposal of filter
cake, municipal treat-
ment of process water,
and discharge of con-
denser water without
cooling or recycle 0.34
17 Containment of filter
muds, biological treat-
ment of process water,
and discharge of con-
denser water without
cooling or recycle 0.43
18 Dry disposal of filter
caKe, biological treat-
ment of process water,
and discharge of con-
denser water without
cooling or recycle 0.43
0.67
0.67
0,67
Yes
134,000 171,000
1.7
No
801,000 245,000
0.2
No
796,000
296,000
-------
REDUCTION BENEFITS: An incremental reduction in plant BOD5 of 0.34 kilo-
grams per metric ton (0*68 pounds per ton) of melt
is evidenced by addition of this Alternative to Al-
termative F. Total reduction of BOD5 and suspended
solids is 100 percent.
Discharge of Process Waste streams to Municipal Treatment Systems. For
the purpose ofpresenting cost information which is representative of
the industry, it is necessary to determine costs associated with various
schemes of discharge to municipal treatment systems. Twelve refineries
currently discharge all or a portion of their wastes to municipal
treatment systems. Seven of these are crystalline refineries with one
other crystalline refinery having sewer hook-up and soon to practice
this treatment technique. The following schemes are possible and the
resulting costs presented.
M.T.#1: Discharge of Process water to
Municipal Treatment
This method of treatment of process water is practiced by twelve
refineries, all urbanly located. This technology is not available to
most rural refineries or to those refineries whose waste is not accepted
by a municipal treatment system. It is however, a well demonstrated
treatment method and practiced by 42 per cent of the nation's
refineries. The costs presented here include the costs associated with
Alternative C.
COSTS: 545 metric tons (600 tons)
per day crystalline refinery
Incremental Investment Cost: $0
Total Investment Cost: $113,000
Total Operating Cost: $ 83,000
Total yearly Cost: $ 90,000*
1900 metric tons (2100 tons)
per day crystalline refinery
Incremental Investment Cost: $0
Total Investment Cost: $134,000
Total Operating Cost: $183,000
Total Yearly Cost: $171,000*
* Includes savings as a result of recovery of sugar which would
normally be entrained in the barometric condenser cooling
water.
M.T.t2: Recycle of Condenser Cooling Water Through
a Cooling Tower with an Assumed Two Per-
cent Slowdown to Municipal Treatment, in
Addition to M.T.tl
127
-------
COSTS: 545 metric tons (600 tons)
per day crystalline refinery
Incremental Investment Cost: $212,000
Total Investment Cost: $325,000
Total Operating Cost: $123,000
Total Yearly Cost: $1U9,000
1900 metric tons (2100 tons)
per day crystalline refinery
Incremental Investment Costs $400,000
Total Investment Cost: $534,000
Total Operating Cost: $276,000
Total Yearly Cost: $303,000
M.T.#3: Recycle of Condenser Cooling Water Through _
a Spray Pond with an Assumed Two Percent
Slowdown to Municipal Treatment, in Addition
to M.T.il
COSTS: 545 metric tons (600 tons)
per day crystalling refinery
Incremental Investment Cost: $148,000
Total Investment Cost; $261,000
Total Operating Cost: $118,000
Total Yearly Cost: $138,000
1900 metric tons (2100 tons)
per day crystalline refinery
Incremental Investment Cost: $284,000
Total Investment Cost: $418,000
Total Operating Cost: $256,000
Total Yearly Cost: $272,000
Liquid Refining
A liquid refinery with an average melt of 508 metric tons (560 tons) of
sugar per day was chosen as the basis for cost estimates. The following
treatment alternatives may be applied to this refinery.
Alternative A: No Waste Treatment or Control.
metric tons (560
The effluent from a 508
tons) per day liquid refinery is 8,590 cubic meters
(2.27 million gallons) per day. The resulting BOD5 and suspended solids
loadings are 3.725 kilograms per metric ton (7.45 pounds per ton) and
8.90 kilograms per metric ton (17.80 pounds per ton) respectively. Be-
cause no waste treatment is involved, no cost can be attributed to this
Alternative.
128
-------
COSTS: 0
REDUCTION BENEFITS: None
Alternative Bj. Elimination of Discharge from Filters. This Alternative
can be achieved either by impounding the mud resulting from slurrying
filter cake with water or by dry hauling the desweetened filter cake to
landfill. The resulting effluent waste loads for BOD5 and suspended
solids are estimated to be 3.25 kilograms per metric ton" (6.50 ' pounds
per ton) and 1.00 kilograms per metric ton (2.00 pounds, per ton) of melt
respectively, at this control level.
B-l:
COSTS:
B-2:
COSTS:
REDUCTION BENEFITS:
Impound Filter Slurry
Incremental Investment Cost: $31,000
Total Investment Cost: $31,000
Total Yearly Cost:1 $12,000
Dry Disposal of Filter Cake
Incremental Investment Cost: $61,000
Total Investment Cost: $61,000
Total Yearly Cost: $45,000
An incremental reduction in BOD5 of approximately
0.475 kilograms per metric ton "(0.95 pounds per
ton) of melt and in suspended solids of approxi-
mately 7.90 kilograms per metric ton (15.80 pounds
per ton) of melt is evidenced over Alternative A.
Total plant reductions of 12.8 percent for BOD5 and
88.8 percent for suspended solids would be achieved.
For the purpose of accruing total costs"in this
section of the report, the use of dry disposal
of filter cake (B-2) will be considered repre-
sentative of Alternative B,
Alternative C: Inpiant Modifications to Reduce Entrainment of Sucrose
into Condenser Water. This Alternative includes, in addition to
Alternative B, the installation of demisters and external separators in
order to reduce the entrainment of sucrose in barometric condenser
cooling water. It is assumed, in addition, that the refinery has good
baffling and operational controls in the evaporators and vacuum pans, as
well as good vapor height. The resulting effluent waste loads for BODji
and suspended solids are 2.90 kilograms per metric ton (5.80 pounds per
ton) of melt and 1.00 kilograms per metric ton (2.00 pounds per ton) of
melt respectively, at this control level.
COSTS: Incremental Investment Cost: $ 54,000
Total Investment Cost: $115,000
Total Yearly Cost: $ 62,000
129
-------
REDUCTION BENEFITS: An incremental reduction in BOD5_ of 0.35 kilograms
per metric ton (0.70 pounds per ton) of melt is
evidenced over Alternative B. The total reduction
in BODji is 22.1 percent and in suspended solids is
88.8 percent.
Alternative D; Biological Treatment of Process Water. This alternative
assumes the addition of an activated sludge plant to treat process
water. Presently there are no refineries which have their own
biological treatment systems, but refinery wastes are commonly treated
in municipal biological treatment plants. As discussed in Section VII,
refinery waste is highly biodegradable and thus well suited for
biological treatment.
A schematic of the activated sludge system is shown in Figure 22. Waste
water is pumped through a primary clarifier to an aerated lagoon with
biological sludge being returned to the aerated lagoon from a secondary
clarifier. Excess sludge is pumped to a sludge digester; the sludge
from the digester is pumped to a holding lagoon. The total effluent
waste loadings as a result of the addition of this Alternative are
estimated to be 0.32 kilograms per metric ton (0.63 pounds per ton) of
melt for BOD5 and 0.165 kilograms per metric ton (0.33 pounds per ton)
of melt for suspended solids.
COSTS:
REDUCTION BENEFITS:
Incremental Investment Cost: $337,000
Total Investment Cost: $452,000
Total Yearly Cost: $230,000
An incremental reduction in BOD5_ of approximately
2,58 kilograms per metric ton (5.16 pounds per ton)
of melt and in suspended solids of 0.835 kilograms
per metric ton (1.67 pounds per ton) of melt is
evidenced over Alternative C. Total reductions of
91.4 percent for BOD5 and 98.1 percent for suspended
solids would be achieved.
Alternative E^ Recycle of Barometric Condenser Cooling Water and
Biological Treatment of Slowdown. ThisAlternative includes, in
addition to Alternative D, the recycle of barometric condenser cooling
water followed by biological treatment of the blowdown in an activated
sludge unit and the addition of sand filtration to further treat the
effluent from the activated sludge unit. The blowdown is assumed to be
approximately two percent of the total condenser flow. Presently there
are three refineries using cooling towers and two which utilize a spray
pond for the purpose of recycling barometric condenser cooling water.
Recycle of barometric condenser cooling water accomplishes two important
things: (1) it cools the water, thereby removing the heat normally
discharged and (2) it concentrates the waste loadings into the smaller
blowdown stream, making biological treatment of this waste stream
feasible. The total effluent waste loadings as a result of the addition
of this Alternative are estimated to be 0.15 kilograms per metric ton
(0.30 pounds per ton) of melt for BOD5_ and 0.03 kilograms per metric ton
(0.06 pounds per ton) of melt for suspended solids. In addition.
130
-------
250,000 kilogram calories per metric ton (0.9 million BTU
melt are effectively removed from condenser water.
per ton) of
Under the most adverse conditions (lack of available land with no
suitable alternative, excessive drift, fogging, noise, or a combination
of these factors), which are presently not anticipated, the costs of
application of this technology (cooling devices) could in some instances
result in significant cost increases.
There are a number of methods of recycling barometric condenser cooling
water; for the purposes of this document, the following are considered:
cooling towers and spray ponds.
E-l:
COSTS:
E-2:
COSTS:
REDUCTION BENEFITS:
Alternative E with a Cooling
Tower
Incremental Investment Cost: $174,000
Total Investment Cost: $626,000
Total Yearly Cost: $265,000
Alternative E with a Spray
Pond
Incremental investment cost: $152,000
Total Investment Cost: $604,000
Total yearly Cost: $261,000
An incremental reduction in BOD5 of 0.17 kilograms
per metric ton (0.34 pounds per ton) of melt and
in suspended solids of 0.135 kilograms per metric
ton (0.27 pounds per ton) of melt is
evidenced by addition of this Alternative to
Alternative D, Total reductions of 96.0 percent
for BOD5 and 99.7 percent for suspended solids
are achieved.
Alternative
Alternative
F:
r Elimination of Discharge of Process Water. Thi s
assumes that, in addition to Alternative C, all process
waters are eliminated by controlled retention and total impoundage. The
resulting effluent waste loading for BOD5_ associated with this control
level is estimated at 0.15 kilograms per metric ton (0.30 pounds per
ton) of melt, that amount attributable to barometric condenser cooling
water. The suspended solids loading is zero as the only suspended
solids-bearing waste stream has been eliminated.
F: Elimination of Discharge of
Process Water by Containment
Total impoundment of process water is successfully practiced by five
refineries; however, a considerable amount of land is required (see
Table 25» Path 13) . Containment of process water is, therefore, not
considered to be practicable technology for urban liquid refineries.
131
-------
TABLE 23
SUMMARY OF WASTE LOADS FROM TREATMENT ALTERNATIVES
FOR THE SELECTED LIQUID REFINERY
Effluent
Constituent
Parameters
Treatment Alternative
Raw
Waste
A
B
C
D* E
** p
G
CO
ro
BOD5. kg/kkg of melt 3.725 3.725
(Ib/ton of melt) (7.45) (7.45)
3.25 2.90 0.32 0.15 0.15 0
(6.50) (5.80) (0.63) (0.30) (0.30) (0)
TSS kg/kkg of melt 8
(Ib/ton of melt)1 (17
DISCHARGE FLOW (m3/kkg)
Barometric Condensers 15
Process Water 1
Filter Slurry
.90
.80)
.0
.64
.25
8.
(17.
15
1
90
80)
.0
.64
.25
1
(2
15
1
.00
.00)
.0
.64
0
1.00
(2.00)
15.0
1.64
0
0.17
(0.33)
15.0
1.64
0
0
(0
0
1
.03
.06)
.30
.64
0
0
(0)
15.0
1.64
0
0
(0)
0.30
1.64
0
* BPCTCA
** BATEA;NSPS
-------
TABLE 24
SUMMARY OF ALTERNATIVE COSTS FOR A 508 METRIC TONS
(560 TONS) PER DAY LIQUID SUGAR REFINERY
Total
\lternative
A
B-l
B-2
C
D
E-l
E-2
F
6-1
6-2
BOD5
Load*
3.725
3.25
3.25
2.90
0.32
0.15
0.15
0.15
0.0
0.0
% BOD5_
Removal
0.0
12.8
12.8
22.2
91.4
96.0
96.0
96.0
100
100
TSS
Load*
8.90
1.00
1.00
1.00
0.165
0.03
0.03
0.0
0.0
0.0
% TSS
Removal
0.0
88.8
88.8
88.8
98.1
99.7
99.7
100
100
100
Investment
Cost
0
31,000
61,000
115,000
452,000
626,000
604,000
1,570,000
2,040,000
2,013,000
Yearly
Operating
Cost
0
5,800
37,000
59,000
194,000
213,000
210,000
74,000
93,000
90,000
Total
Yearly
Cost
0
12,000
45,000
62,000**
230,000
265,000
261 ,000
217,000
280,000
275,000
*Waste Loadings in Kilograms per Metric Ton of Melt
**Includes Sugar Savings of $10,000/yr. as a Result
of Entrainment Prevention.
133
-------
TABLE 25
GJ
Path
Description
of Path
IMPLEMENTATION SCHEDULES FOR A LIQUID SUGAR REFINERY
BOD Heat Hectares of Total Yearly
Loading Loading Available Municipal Costs
Discharged Discharged Land Sewer Investment Including
kg/kkg k-Cal/kkg Required Required Cost Power
1 Containment of filter
muds, all process
water, and blowdown
from cooling tower
2 Containment of filter
muds, all process
water, and blowdown
from spray pond
3 Containment of filter
muds and discharge
process water and
blowdown from cooling
tower to municipal
treatment
4 Containment of filter
muds and discharge of
process water and
blowdown from spray
pond to municipal
treatment
5 Dry disposal of filter
cake and containment
of all process waters
and blowdown from
cooling tower
51
No
51
NO
0
0.5
Yes
0.5
Yes
50
No
2,010,000 247,000
1,980,000 242,000
186,000
164,000
2,040,000
77,000
72,000
280,000
-------
TABLE 25
IMPLEMENTATION SCHEDULES FOR A LIQUID SUGAR REFINERY
(Continued)
Path
BOD Heat Hectares of
Loading Loading Available Municipal
Description Discharged Discharged Land Sewer
of Path kg/kkg k-Cal/kkg Required Required
Total Yearly
Costs
Investment Including
Cost Power
CO
Ul
6 Dry disposal of filter
cake and containment of
all process water and
blowdown from spray
pond
7 Dry disposal of filter
cake with discharge of
process waters and
blowdown from cooling
tower to municipal
treatment
8 Dry diposal of filter
cake and containment
of all process water and
blowdown from spray pond
to municipal treatment
9 Containment of filter
muds and biological
treatment of process
water and blowdown
from cooling tower, fol-
lowed by sand filtr.
10 Containment of filter
muds and biological
treatment of process
water and blowdown
from spray pond, fol-
lowed by sand filtr.
50
No
2,010,000
275,000
0.1
Yes
216,000
110,000
0.1
Yes
194,000
105,000
0.15
0.6
No
596,000
232,000
0.15
0.6
No
574,000
228,000
-------
TABLE 25
IMPLEMENTATION SCHEDULES FOR A LIQUID SUGAR REFINERY
(Continued)
Path
11 Drv
Description
of Path
' disposal of fi Iter
BOD
Loading
Discharged
kg/kkg
Heat
Loading
Discharged
k-Cal/kkg
Hectares of
Available
Land
Required
Municipal
Sewer
Required
Investment
Cost
Total Yearly
Costs
Including
Power
cake and biological
treatment of process
water and blowdown
from cooling tower, fol-
lowed by sand filtr. 0.15
12 Dry disposal of filter
cake and biological
treatment of process
water and blowdown
from spray pond, fol-
lowed by sand filtr. 0.15
13 Containment of filter
muds and process waters
and discharge of con-
denser water without
cooling or recycle 0.15
14 Containment of filter
muds, municipal treat-
ment of process waters,
and discharge of con-
denser water without
cooling or recycle 0.15
15 Dry disposal of filter
cake, containment of
process water and dis-
charge of condenser
water without cooling
or recycle 0.15
0.2
No
626,000
265,000
0.3
No
604,000
261,000
0.25
41
No 1,540,000
184,000
0.25
0.4 Yes
85,000
51,000
0.25
40
No 1,570,000
217,000
-------
TABLE 25
Path
Description
of Path
IMPLEMENTATION SCHEDULES FOR A LIQUID SUGAR REFINERY
(Continued)
BOD Heat Hectares of Total Yearly
Loading Loading Available Municipal Costs
Discharged Discharged Land Sewer Investment Including
kg/kkg k-Cal/kkg Required Required Cost Power
16 Dry disposal of filter
cake, municipal treat-
ment of process water,
and discharge of con-
denser water without
cooling or recycle 0.15
17 Containment of filter
muds, biological treat-
ment of process water,
and discharge of con-
denser water without
cooling or recycle 0.32
18 Dry disposal of filter
cake, biological treat-
ment of process water,
and discharge of con-
denser water without
cooling or recycle 0.32
0.25
0.25
0.5
0.25
0.2
Yes
115,000
84,000
No
422,000
197,000
No
452,000
230,000
-------
COSTS;
REDUCTION BENEFITS:
Incremental Investment Cost: $1,455,000
Total Investment Cost: $1,570,000
Total Yearly Cost: $ 217,000
An incremental reduction in plant BOD5 of 2.75
kilograms per metric ton (5.50 pounds per ton)
of melt and in suspended solids of 1.00 kilograms
per metric ton (2.00 pounds per ton) of melt is
evidenced in comparison to Alternative C. Total
reductions in BOD5 of 96.0 percent and in sus-
pended solids of 100 percent are achieved.
Alternative G; Elimination of Discharge of Barometric Condenser Cooling
Water. This Alternative assumes that in addition to Alternative P there
is an elimination of discharge of barometric condenser cooling water.
To achieve this level of treatment, it has been assumed that condenser
water is recycled and the blowdown impounded or discharged to a
municipal treatment system. The blowdown of barometric condenser
cooling water is assumed to be two percent of the total condenser flow.
Effluent waste loads associated with this control level are zero
kilograms per metric ton (zero pounds per ton) of melt.
G-1: Recycle of Condenser Water Through
a Cooling Tower with an Assumed Two
Percent Blowdown to Controlled Land
Retention, in Addition to Alterna-
tive F.
COSTS;
G-2:
COSTS:
REDUCTION BENEFITS:
Incremental Investment Cost: $ 470,000
Total Investment Cost: $2,040,000
Total Yearly Cost: $ 280,000
Recycle of Condenser cooling Water
Through a Spray Pond with an Assumed
Two Percent Blowdown to Controlled Land
Retention in Addition to Alternative F.
Incremental Investment Cost: $ 443,000
Total Investment Cost: $2,013,000
Total Yearly Cost: $ 275,000
An incremental reduction in plant BOD5 of 0.15
kilograms per metric ton (0.30 pounds^per ton)
of melt is evidenced by addition of this
Alternative to Alternative F. Total reductions
of BOD5 and suspended solids are 100 percent.
Discharge of Process Waste Streams to Municipal Treatment System. For
the purpose of presenting cost information which is representative of
138
-------
the industry, it is necessary to determine costs associated with various
schemes of discharge to municipal treatment systems. Twelve refineries
currently discharge all or a portion of their wastes in municipal
treatment systems. Three of these are liquid refineries and two are
combination crystalline - liquid refineries. The following schemes are
possible and the resulting costs presented.
M.T.il: Discharge of Process Water to
Municipal Treatment
This method of treatment of process water is practiced by three of the
five liquid refineries and by both combination crystalline - liquid
refineries, all urbanly located. This technology is not available to
most rural refineries or to those refineries whose waste is not accepted
Dy a municipal treatment system. It is however, a well demonstrated
treatment method and practiced by 42 percent of the nation's refineries.
The costs presented include those costs attributable to Alternative C.
COSTS: Incremental Investment Cost: $0
Total Investment Cost: $115,000
Total Operating Cost: $ 81,000
Total Yearly Cost: $ 84,000*
* Includes savings as a result of recovery of sugar which would
normally be entrained in the barometric condenser cooling
water.
M.T.#2: Recycle of Condenser Cooling Water Through
a Cooling Tower with an Assumed Two Percent
slowdown to Municipal Treatment, in Addition
to M.T. #1
COSTS: Incremental Investment cost: $101,000
Total Investment Cost: $216,000
Total Operating Cost: $ 97,000
Total Yearly Cost: $110,000
M.T.#3: Recycle of Condenser Cooling Water Through
a Spray Pond with an Assumed Two Percent
Slowdown to Municipal Treatment, in
Addition to M.T.#1
COSTS: Incremental Investment Cost: $ 79,000
Total Investment Cost: $194,000
Total Operating Cost: $ 94,000
Total Yearly Cost: $105,000
139
-------
RELATED ENERGY REQUIREMENTS OF ALTERNATIVE TREATMENT AND
CONTROL TECHNOLOGIES - CANE SUGAR REFINING
To process 0.9 metric tons (one ton) of raw sugar into refined sugar, it
is estimated that 60 and 64 kilowatt-hours of electricity are required
for crystalline and liquid sugar refineries, respectively. This elec-
trical energy is affected by process variations, in-place pollution
control devices, and amount of lighting.
At a cost of 2.3 cents per kilowatt-hour, a crystalline sugar refinery
processing 136,250 metric tons (150,000 tons) of raw sugar per year,
would have a yearly energy cost of $209,000. Associated with the
control alternatives are additional annual energy costs. These are
estimated to be:
Alternatives
A
B-l
B-2
C
D
E-l
E-2
F
G-l
G-2
M.T. #1
M.T. #2
M.T. #3
Cost
-0-
300
1,200
1,200
8,140
27,000
27,000
1,460
19,700
14,000
1,200
19,300
13,600
At a cost of 2.3 cents per kilowatt-hour, a crystalline cane sugar
refinery processing 475,000 metric tons (525,000 tons) of raw sugar per
year would have a yearly energy cost of $725,000. Associated with the
control alternatives are additional annual energy costs. These are
estimated to be:
Alternatives
A
B-l
B-2
C
D
E-l
E-2
F
G-l
G-2
M.T. #1
M.T. #2
M.T. #3
Cost
-0-
500
1,200
1,200
28,000
83,000
71,000
1,600
51,800
40,400
1,200
51,200
39,800
At a cost of 2.3 cents per kilowatt-hour, a liquid cane sugar refinery
processing 127,000 metric tons (140,000 tons) of raw sugar per year
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would have a yearly energy cost of $206,000. Associated with the
control alternatives are additional annual energy costs. These are
estimated to be:
Alternatives
A
B-l
B-2
C
D
E-l
E-2
F
G-l
G-3
M.T, #1
M.T. #2
M.T. #3
Cost
; -o-
300
1,200
1,200
21,300
27,000
26,000
1,400
6,500
5,300
1,200
6,200
5,100
NON-WATER QUALITY ASPECTS OF ALTERNATIVE TREATMENT AND CONTROL
TECHNOLOGIES '""""'
Air Pollution
Waste water lagooning, particularly under anaerobic conditions, can
promote the growth of sulfur reducing organisms and associated noxious
gases. The maintenance of aerobic conditions can be maintained by the
design of shallow ponds (two feet or less), by the use of aerators
(although these can increase an existing problem), by pH adjustment, or
by other means.
Solid Wastes
The removal of solids from waste water produces a solid waste disposal
problem in the form of sludges. In these cases, where the sludges are
to be impounded, previously discussed measures for protection of ground
water must be taken. Sanitary landfills, when available, usually offer
an economical solution if hauling distances are reasonable. The addi-
tional solids waste produced by waste water treatment is not expected to
be a significant problem. Technology and knowledge are available to
prevent harmful effects to the environment as a result of land disposal
of sludge.
Non-Water Quality Aspects of Cooling Towers or Other Cooling Devices
The non-water quality environmental impacts which may be of significance
as a result of the application of cooling towers or other cooling
devices for the recirculation of barometric condenser cooling water or
which must be minimized include drift, fogging, and noise.
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Drift. Water vapor and heated air are not the only effluents from
cooling towers. Small droplets of cooling water become entrained in the
air flow, and are carried from the tower. These droplets have the same
composition as the cooling water; the water may evaporate from the
drops, leaving behind the dissolved solids which are present in the
cooling water.
The amount of drift is basically a function of cooling tower design, and
particularly of the drift eliminators. The drift from mechanical
cooling towers is on the order of O.OQ5X of tower flow, while drift from
natural draft towers is on the order of half that of mechanical towers.
If the tower drift results in an increased salt load on the surrounding
area of only a few percent of the natural salt deposition rate, the
effect is probably minimal.
Adverse environmental impacts due to drift are a local rather than a
uniform national problem. Technology exists at a moderate cost which
enables the integration of low drift levels into the overall tower
design. In addition, proper location of the tower with regard to
prevailing winds and the uses of surrounding land can be employed to
meet stringent drift requirements.
Fogging. Fogging is one of the more noticeable effects resulting from
the installation of cooling devices. Fog results when warm, moist air
mixes with cooler ambient air. As the warm, moist air cools, it may
reach saturation and then supersaturation. when this occurs, the water
vapor condenses and forms droplets of fog. The production of fog by
cooling devices is primarily a function of local climatic conditions*
Those areas normally susceptible to cooling tower fog are those areas in
which natural fog occurs frequently.
The fog plume from mechanical draft towers is emitted close to the
ground. Under certain meteorological conditions, the fog may drop to
the ground and could cause hazardous driving conditions on nearby
roadways. Careful placement of the cooling device will eliminate most
of the problems. If placement is unsatisfactory and creation of safety
hazards is still anticipated, the use of a wet-dry tower can
significantly reduce fog plumes. It should be noted that a wet-dry
tower is more expensive than the conventional wet tower.
Noise. The problem of noise pollution should be considered while
designing a cooling tower. All cooling towers produce some noise due to
falling water and/or the operation of fans. A three stage procedure
usually results in adequate coverage:_of _ajny_jioise_ problems._i_f_±hey are
anticipated while in the cooling tower design stage. These include: ~~~~
1. Establishing a noise level which is acceptable to those within
hearing range of the tower,
2. Estimate the anticipated tower noise levels, taking into account
distance to neighbors and location of the tower, and
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3. A comparison of the tower noise level to that of the acceptable
noise level.
Only if the tower noise level is in excess of the acceptable noise level
is corrective action necessary.
If the tower noise is of greater magnitude than normal refinery noise, a
problem could exist in noise sensitive areas. Every effort should be
made to locate these structures away from potential sources of
complaint. Sound levels decrease with the square of the distance from
the source of the noise. Walls and buildings may act as sould barriers,
thus reducing any problems. Pan speeds can be reduced, if the tower is
over-designed, thus reducing noise. Proper attention to noise problems
during tower design and placement can avoid costly corrective measures.
If the above procedures are unable to reduce noise levels to acceptable
levels, sound attenuation can be achieved by modification of or addition
to the tower. Discharge baffles and accoustically lined plenums can be
utilized; barrier walls or baffles can be erected. Proper design and
operation can minimize the expense involved in noise suppression.
Adverse noise impacts are a local rather than a uniform national
problem. Technology is available at a moderate cost to reduce the noise
impact due to the addition of cooling towers.
Additional Installation costs
There are certain situations where the addition of a cooling tower or
other cooling device could be impractical or uneconomical. One of these
situations is a location in a downtown area where the surrounding land
is already highly developed and unavailable. In these situations, other
alternatives exist such as installing the cooling tower on the roof, in
the basement, above a parking lot, or on land already in the possession
of the cane sugar refinery. These alternatives may or may not result in
significant cost increases.
Other factors such as drift, fogging, and noise problems can be designed
around in most situations. This may or may not result in signficiant
cost increases.
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SECTION IX
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF
THE BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
EFFLUENT LIMITATIONS GUIDELINES
INTRODUCTION
The effluent limitations which must be achieved by July 1, 1977, are to
specify the degree of effluent reduction attainable through the applica-
tion of the best practicable control technology currently available.
Best practicable control technology currently available is generally
based upon the average of best existing performance by plants of various
sizes, ages and unit processes within the industrial category and/or
subcategory.
Consideration must also be given to:
a. The total cost of application of the technology in relation
to the effluent reduction benefits to be achieved from such
application;
b. The size and age of equipment and facilities involved;
c. The process employed;
d. The engineering aspects of the application of various types
of control techniques;
e. Process changes;
f. Non-water quality environmental impact (including energy
requirements) ;
Best practicable control technology currently available emphasizes
treatment facilities at the end of a manufacturing process but includes
the control technologies within the process itself when these are
considered to be normal practice within the industry.
A further consideration is the degree of economic and engineering
re 1 iabi lity which must be est ablis hed for th e technology to be
"currently available". As a result of demonstration projects, pilot
plants, and general use, there must exist a high degree of confidence in
the engineering and economic practicability of the technology at the
time of construction or installation of the control facilities.
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APPLICATION
OF
BEST
EFFLUENT REDUCTION ATTAINABLE THROUGH THE r
PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE FOR THE CANE SUGAR
REFINING SEGMENT ~
Based upon the information contained in Sections III through VIII of
this document, it has been determined that the degree of effluent
reduction attainable through the application of the best practicable
control technology currently available is that resulting from maximum
sucrose entrainment prevention in barometric condenser cooling water,
elimination of a discharge of filter cake, and biological treatment of
all process water other than uncontaminated (non-contact) cooling water
and barometric condenser cooling water. The effluent levels attainable
for this degree of reduction are shown in Table 1.
Effluent Limitations Guidelines Development
For the purpose of establishing uniform national effluent limitations
guidelines, model refineries were hypothesized which represent the
crystalline and liquid cane sugar refining subcategories of the sugar
processing point source category. Within both subcategories of the cane
sugar refining segment, presently employed end-of-pipe treatment
consists of either discharge to municipal treatment systems or
impoundage (total or partial) of the waste water stream. Neither of
these technologies is available to the entire cane sugar refining
segment. In the development of uniform national standards, it is
necessary to base effluent limitations guidelines upon technology which
is practicable by all elements of the industry segment. The technology
on which the guidelines are based is biological treatment, namely
activated sludge. Biological treatment is a practicable technology,
demonstrated by its use in the treatment of waste waters similar in
nature to those associated with cane sugar refining. Because this
technology is not presently employed, an average rather than exemplary
plant approach is taken in the determination of water usages and
effluent raw waste loadings on which to base effluent reductions
attainable and costs associated with the application of various control
and treatment technologies. The model refineries which are
representative of the crystalline and liquid cane sugar refining
subcategories are derived from a basis of average rather than exemplary
water usage. BODjj and TSS raw waste loadings are based upon average to
poor, rather than exemplary in-plant control practices.
The initial step in guidelines development involved the separation of
the waste water effluent to reflect the two major waste streams,
barometic condenser cooling water and process water. To these two
streams were applied the model technologies: sucrose entrainment
prevention in the case of barometric condenser cooling water and
biological treatment in the case of the process water stream.
Reasonable levels of control or treatment are specified for both waste
water streams. It is felt that the levels of treatment specified in the
prior Development Document for Proposed Effluent Limitations Guidelines
and New Source Performance Standards for the CANE SUGAR REFINING Segment
of the Sugar Processing Point Source Category are reasonable and
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attainable. The guidelines have been relaxed to allow for possible
operational problems resulting from a specified treatment technique
(activated sludge biological treatment) which, while practicable, is not
currently industry practice.
It is felt that the effluent limitations guidelines presented in this
section are reasonable and technically easily achievable through the
application of improved in-plant controls and the addition of an
appropriate treatment system to treat the process water stream. The
conservative rather than the exemplary plant approach was taken to
ensure that the effluent limitations guidelines are viable to the cane
sugar refining industry as a whole and because the activated sludge
treatment system, while practicable, is not currently industry practice.
BQD5. The final BOD5 limits were derived fcy separating the waste water
effluent to reflect the two major waste streams, barometric condenser
cooling water and process water. It is assumed that the model
biological treatment system will attain reductions in the process water
BOD5 loading to 60 and 100 mg/1 for the crystalline and liquid cane
sugar refining subcategories, respectively. It is assumed tiiat by
utilizing proper control, the net BOD5 associated with the barometric
condenser cooling water stream will be limited to 10 mg/1. The addition
of the net BOD5 attributable to the barometric condenser cooling water
stream to that amount of BOD5 incorporated into the process water
effluent stream results in the limitation guideline. Where the
barometric condenser cooling water and process water streams are mixed
and impossible to measure separately prior to discharge, the BODS value
should be considered net. "*"
This does not imply that plants must necessarily duplicate the assumed
raw waste loadings, water usage, and treatment efficiencies. It is
possible for plants to achieve the indicated final effluent waste
loadings by operating at lower average treatment efficiencies but
receiving lower pollutional raw waste loadings and/or using less process
or barometric condenser cooling water. In addition, an entirely
different approach such as disposal by controlled irrigation or
controlled land impoundage may be employed.
TSS. The final effluent TSS limitations were derived by assuming
process water TSS loading reductions to 60 and 100 mg/1 for the
crystalline and liquid cane sugar refining subcategories, respectively.
No TSS, limit has been established for the barometric condenser cooling
water stream because of the low TSS raw waste loading associated with
this waste water stream. Where the barometric condenser cooling water
and process water streams are mixed and impossible to measure separately
prior to discharge, the TSS value should be considered net.
Establishment of Daily Average Effluent Limitations Guidelines. Based
upon an analysis of biological treatment systems operating on wastes
similar in nature to those associated with cane sugar regining and upon
engineering judgement, the following ratios of daily maximum to monthly
average limitations are established:
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— Barometric condenser cooling water will be three times the
monthly average for BOD5 for both the crystalline and liquid
cane sugar refining subcategories.
— Process water will be two times the monthly average for BOD5 and
three times the monthly average for TSS for both the crystalline
and liquid cane sugar refining subcategories.
Production Basis. The average permitted effluent level should be the
recommended level, expressed as kg/kkg (Ib/ton) of melt, multiplied by
the present daily processing rate, expressed as kkg (ton) per day of
melt. It is recommended that the daily processing rate be based on the
highest average rate sustained over thirty (30) consecutive days (not
necessarily continuous) of full normal production. This should provide
a period of time long enough to dampen the effect of non-typical minimum
or maximum periods and___ allows for a limitation based on actual
production history rather than ^rT rated-capacity*. ____
It is recommended that for combined crystalline-liquid cane sugar
refineries, the limitations be based on a weighted average of those
fractions of liquid and crystalline production.
Identification
Available
of Best Practicable control Technology Currently
Best practicable control technology currently available for the cane
sugar refining segment of the sugar processing category is the recycle
and reuse of certain process waters within the refining process, the
minimization of sucrose entrainment in barometric condenser cooling
water, the elimination of a discharge of filter cake, and the biological
treatment of excess process waters, implementation of this requires the
following:
a. Collection and recovery of all floor drainage.
b. Minimization of sucrose entrainment in barometric condenser
cooling water by the use of improved baffling systems,
demisters, and/or other control devices.
c. Dry handling of filter cakes after desweetening with disposal to
sanitary landfills, or complete containment of filter cake
slurries.
d. Biological treatment of all waste water discharges other than
uncontaminated (non-contact) cooling water and barometric
condenser cooling water.
Engineerincr Aspects of control Technique Applications
The technology defined for this level is practicable. There are
refineries which currently collect all floor drainage. Most refineries
currently achieve either dry handling or complete containment of filter
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cake. All of the control devices described for entrainment control have
been demonstrated by various refineries. Biological treatability of
refinery waste waters has been demonstrated by the twelve refineries
that discharge process water to municipal biological treatment systems.
Costs of Application
The costs of attaining the effluent reductions set forth herein are
summarized in Section VIII, Cost, Energy. and Non-Water pualitv Aspects.
The investment costs associated with this level of technology represent
approximately 2% of the total investment needed to build the typical re-
finery. The total capital cost to the cane sugar refining segment is
approximately $5/910,000. It is estimated that $5.6 million of this
total is associated with the crystalline cane sugar refining subcategory
and that $0.31 million is associated with the liquid cane sugar refining
subcategory.
Non-water Quality Environmental Impact
The primary non-water quality environmental impacts are summarized in
Section VIII, Cost^ Energy and Non-water Quality Aspects. The major
concern is the strong reliance upon the land for ultimate disposal of
wastes. However, the technology is available to assure that land dis-
posal systems are maintained commensurate with soil tolerances.
A secondary concern is the generation of solid wastes in the form of
sludges and muds and the possibility of odors resulting from impoundage
lagoons. In both cases, responsible operation and maintenance
procedures coupled with sound environmental planning have been shown to
obviate the problems.
It is estimated that the increase in energy necessary to implement the
required control and treatment amounts to 0.84% of the current energy
usage for the crystalline cane sugar refining subcategory and 0.6% for
the liquid cane sugar refining subcategory.
Factors to be Considered in Applying Effluent Limitations
The above assessment of what constitutes the best practicable control
technology currently available is predicated on the assumption of a
degree of uniformity among refineries that, strictly speaking, does not
exist. Tables 21, 22, and 2 5 list various treatment contro1
alternatives (i.e., discharge of waste waters to municipal treatment
systems) and summarize requirements and benefits associated with each.
It is believed that the data in these tables can be a valuable aid in
assessing problems and associated solutions for individual
installations.
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SECTION X
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF
THE BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE
EFFLUENT LIMITATIONS GUIDELINES
INTRODUCTION
The effluent limitations which must be achieved by July 1, 1983, are to
specify the degree of effluent reduction attainable through the
application of the best available technology economically achievable.
The best available technology economically achievable is not based upon
an average of the best performance within an industrial category, but is
to be determined by identifying the very best control and treatment
technology employed by a specific point source within the industrial
category or subcategory, or where it is readily transferable, from one
industrial process to another. A specific finding must be made as to
the availability of control measures and practices to eliminate the
discharge of pollutants, taking into account the cost of such
elimination.
Consideration must also be given to:
(a)
(c)
(e)
(f)
the age of equipment and facilities involved;
the process employed;
the engineering aspects of the application of
various types of control techniques;
process changes;
cost of achieving the effluent reduction
resulting from application of the best
economically achievable technology;
non-water quality environmental impact
(including energy requirements) .
In contrast to the best practicable control technology currently avail-
able, the best economically achievable technology assesses the availa-
bility in all cases of in-process controls as well as control or addi-
tional treatment techniques employed at the end of a production process.
Those plant processes and control technologies which at the pilot plant
semi-works, or other levels, have demonstrated both technological per-
formances and economic viability at a level sufficient to reasonably
justify investing in such facilities may be considered in assessing the
best available economically achievable technology. The best available
economically achievable technology is the highest degree of control
technology that has been achieved or has been demonstrated to be capable
of being designed for plant scale operation up to and including "no
discharge" of pollutants. Although economic factors are considered in
this development, the costs for this level of control are intended to be
the top-of-the-line of current technology subject to limitations imposed
by economic and engineering feasibility. However, the best available
technology economically achievable may be characterized by some
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•technical risk with respect to performance and with respect to certainty
of costs. Therefore, the best available technology economically
achievable may necessitate some Industrially sponsored development work
prior to its application.
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF THE._BEST
AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE—EFFLUENT LIMITATIONS
GUIDELINES
Based upon the information contained in this document, it has been
determined that the degree of effluent reduction attainable through the
application of the best available technology economically achievable is
that resulting from the technology of cooling and recycling barometric
condenser cooling water with biological treatment of the blowdown and
the addition of sand filtration to further treat the effluent from the
biological treatment system. The effluent levels attainable for this
degree of reduction are shown in Table 1.
Effluent Limitations Guidelines Development
The effluent limitations guidelines associated with best practicable
control technology currently available (discussed in section IX) were
modified from those levels which were proposed in the December 1973
Development Document, to reflect the possible operational problems
associated with the application of a treatment technique (activated
sludge biological treatment) which is not currently industry practice.
It is felt that by 1983 there will be sufficient experience gained by
operators of these systems to minimize these operational problems. The
levels of reduction recommended for best available technology
economically achievable reflect this feeling.
BODS. Based on improved operation of the properly designed biological
treatment system, effluent BOD5 levels of 40 mg/1 for the crystalline
and 75 mg/1 for the liquid cane sugar refining subcategories have been
determined to be realistic. No credit for BOD5 removal as a result of
solids removal in the sand polishing operation has been assumed. This
is because of the uncertainty at present of the ratio of soluble to
insoluble BOD in the effluent from the biological treatment system. The
effluent limitations guidelines recommended through application of the
best available technology economically achievable may have to be
modified at a later date to reflect that amount of BOD5 which is removed
in the sand polishing step.
TSS. It has been determined that at the effluent waste loadings
entering the sand filtration units from the activated sludge system, a
waste loading from the sand filtration units of 15 mg/1 TSS can be
readily achieved.
Establishment of Daily Average Effluent Limitations Guidelines. Based
of biological treatment systems operating on wastes
upon
upon an analysis
similar in nature to those associated with cane sugar refining and
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engineering judgment, the following ratios of daily maximum to monthly
average limitations are established:
BOD5: The daily maximum will be two times the monthly average
for" both the crystalline and liquid cane sugar refining
subcategories.
TSS: The daily maximum will be three times the monthly average
for both the crystalline and liquid cane sugar refining
subcategories.
Production Basis. The average permitted effluent level should be the
recommended level, expressed as kg/kkg (Ib/ton) of melt, multiplied by
the present daily processing rate, expressed as kkg (ton) per day of
melt. it is recommended that the daily processing rate be based on the
highest average rate sustained over thirty (30) consecutive days (not
necessarily continuous) of full normal production. This should provide
a period of time long enough to dampen the effect of non-typical minimum
or maximum periods and allows for limitations based on actual production
history rather than on rated capacity.
It is recommended that for combined crystalline - liquid cane sugar
refineries, the limitations be based on a weighted average of those
fractions of liquid and crystalline production
Identification of Best Available Technology Economically Achievable
Best available technology economically achievable for the cane sugar
refining segment of the sugar processing industry is that technology
described in section IX of this document with the addition of a cooling
and recycling system for barometric condenser cooling water, with the
blowdown from the recirculation system being discharged to the
biological treatment system, and the addition of sand filtration to
further treat the effluent from the biological treatment system.
Implementation of this technology requires the following:
a. That technology described as best practicable control technology
currently available, discussed in Section IX.
The addition of a cooling device to allow for the
and reuse of barometric condenser cooling water.
recirculation
c. The expansion of the biological treatment system, which treats
the process water stream, in order to treat the blowdown from
the barometric condenser cooling water recirculation system.
d. The addition of sand filtration to further
from the biological treatment system.
treat the effluent
Alternatives to this system could include controlled irrigation with all
or a portion of the waste water streams, controlled impoundage of the
waste water streams, the addition of surface condensers to replace
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barometric condensers (-thus eliminating sucrose entrair.ment in condenser
cooling waters), or the further reduction of sucrose entrainment in
barometric condenser cooling water.
r.
The effluent limitations guidelines are based on the treatment of all
waste water streams. It is possible that through the application o'f
improved control devices, sucrose entrainment in condenser cooling water
could be further minimized or, as some industry sources have indicated,
might be totally eliminated. One factor in applying the effluent
limitations specified as best available technology economically.
achievable is the issue of net versus gross limitations. The Agency
recognizes that in certain instances pollutants may be present in the
navigable waters which supply a plant's intake water in significant
concentrations which may not be removed to the levels specified in the
guidelines by the application of the best available technology
economically achievable or its alternatives. At the time of publication
of this document, the Agency was reviewing the net versus gross issue
and was contemplating amendments to its NPDES permit regulations which
would specify the situations in which the Regional Administrator may
allow a credit for such pollutants.
Engineering Aspects of control Technique Applications
The recirculation of barometric condenser cooling water is currently
practiced by five cane sugar refineries utilizing cooling towers, spray
ponds, and canal systems. The biological treatment of the blowdown from
the barometric condenser cooling water recirculation system has been
demonstrated to a limited extent in the cane sugar refining industry
(one refinery discharges cooling tower blowdown to a municipal treatment
system) and to a greater extent in the soaps and detergents, oil
refining, and grain milling industries. Sand filtration is a well-
demonstrated polishing technique, widely used in both water supply and
in waste water treatment.
Costs of Application
The costs of attaining the effluent reductions set forth herein are
summarized in. Section VIII, cogt^ Energy,, and Non-water Quality Aspects.
The investment costs associated with the level of technology represent
approximately 3.5 percent of the total investment needed to build the
typical refinery. The total capital cost to the cane sugar refining
segment is approximately $15,000,000 or $9,100,000 above that required
to achieve the best practicable control technology currently available.
It is estimated that $14.2 million of the total is associated with the
crystalline cane sugar refining subcategory and that $0.8 million is
associated with the liquid cane sugar refining subcategory.
Under the most adverse conditions, which are presently not anticipated,
the costs of application of this technology could, in some instances,
result in significant cost increases, as discussed in Section VIII.
However, the provisions of the "Act" provide for the consideration of
unusual adverse economic affects which would result from compliance with
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these limitations. On an indvidual basis the "Act" provides that the
Administrator may modify the effluent limitations guidelines upon a
showing by the owner or operator that such modified requirements will
represent the maximum use of technology within the economic capability
of the owner or operator and will result in reasonable further progress
toward the elimination of the discharge of pollutants.
Non-Water Quality Environmental Impact
The non-water quality environmental impact would be an intensification
of those impacts described in Section IX, plus those impacts associated
with cooling devices (i.e., drift, fogging, and noise). Drift, fogging,
and noise can be reduced through proper design and location, and can be
minimized in most situations.
It is estimated that the increase in energy necessary to implement the
required control and treatment amounts to 6.1% of the current energy
usage for the crystalline cane sugar refining subcategory and 1.9% for
the liquid cane sugar refining subcategory.
Factors to be Considered in Applying Effluent Limitations
The same factors as discussed in Section IX should be considered for
this level. For refineries in rural areas, spray ponds or irrigation
canals may be more feasible for recycling barometric condenser cooling
water than cooling towers. Tables 21, 22, and 25 list various treatment
and control alternatives and summarize the requirements and benefits
associated with each.
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SECTION XI
NEW SOURCE PERFORMANCE STANDARDS
INTRODUCTION
In addition -to guidelines reflecting the best practicable control
technology currently available and the best available technology
economically achievable, applicable to existing point source discharges
July 1, 1977, and July 1, 1983, respectively, the Act requires that
performance standards be established for new sources. The term "new
source" is defined in the Act to mean "any source, the construction of
which is commenced after the publication of proposed regulations
prescribing a standard of performance". New source technology shall be
evaluated by adding to the consideration underlying the identification
of best available technology economically achievable a determination of
what higher levels of pollution control are available through the use of
improved production processes and/or treatment techniques. Thus, in
addition to considering the best in-plant and end-of-process control
technology, identified in best available technology economically
achievable, new source technology is to be based upon an analysis of how
the level of effluent may be reduced by changing the production process
itself. Alternative processes, operating methods or other alternatives
must be considered. However, the end result of the analysis will be to
identify effluent standards which reflect levels of control achievable
through the use of improved production processes (as well as control
technology), rather than prescribing a particular type of process or
technology which must be employed. A further determination which must
be made for new source technology is whether a standard permitting no
discharge of pollutants is practicable.
Specific Factors to be Taken into Consideration
At least the following factors should be considered with respect to
production processes which are to be analyzed in assessing new source
technology:
(a) the type of process employed and process changes;
(b) operating methods;
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potential of development, it is not possible to determine, within
reasonable accuracy, the potential waste reductions achievable through
their application in new sources. However, the implementation of those
in-plant and end-of-pipe controls described in section VII, Control and
Treatment Technology* would enable new sources to achieve the effluent
discharge levels defined in Section X.
The short lead time for application of new source performance standards
(less than a year versus approximately four and ten years for other
guidelines) affords little opportunity to engage in extensive
development and testing of new procedures. The single justification for
more restrictive limitations for new sources than for existing sources
would be one of relative economics of installation in new plants versus
modification of existing plants. There is no data to indicate that the
economics of the application of in-plant and end-of-pipe technologies
described in Section VII, Control and Treatment Technology , would be
significantly weighted in favor of new sources.
The attainment of zero discharge of pollutants does not appear to be
feasible for cane sugar refineries, other than those with sufficient and
suitable land for irrigation or total impoundage of waste waters.
In view of the aforegoing, it is recommended that the effluent
limitations for new sources be the same as those determined to be best
available control technology economically achievable, presented in
Section X.
158
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SECTION XII
ACKNOWLEDGEMENTS
The Environmental Protection Agency wishes to acknowledge the
contributions of Environmental Science and Engineering, Inc., (ESE) of
Gainesville, Florida, with the assistance of F. C. Schaffer and
Associates, Inc. (FCS) of Baton Rouge, Louisiana, and Reynolds, Smith
and Hills (RSSH) of Jacksonville, Florida. The work of ESE was
performed under the direction of Dr. Richard H. Jones, Project Director,
Mr. John D. Crane, Project Manager, and Mr. Robert A. Morrell,
Assistant Project Manager.
Appreciation is expressed to those in the Environmental Protection
Agency who assisted in the performance of the project: Kenneth Dostal,
NERC, Corvallis; Erik Krabbe, Region II; Ed Struzeski, NFIC, Denver;
Karl Johnson, ORAP, Headquarters; George Keeler, ORSD Headquarters;
Allen Cywin, Ernst P. Hall, C. Ronald McSwiney, George R. Webster, John
Riley, Richard V. Watkins, Linda K. Rose, and Bobby J. Wortman, Effluent
Guidelines Division; and many others in the EPA regional offices and
research centers who assisted in providing information and assistance to
the project. Special acknowledgement is made of the assistance given by
Robert W, Dellinger, Project Officer, whose leadership and direction on
this program are most appreciated.
Appreciation is extended to Mr. Irving Hoff of the United States Cane
Sugar Refiners1 Association (USCSRA) and to the members of the USCSRA
Environmental Task Force for their willing cooperation. Appreciation is
particularly extended to individuals within the refining industry who
provided assistance and cooperation in supplying information and
arranging on-site visits. Individuals who particularly deserve mention
are Mr. Thomas Baker of Amstar Corporation, Mr. Rufus Herring of the
Savannah Refinery, Mr. Fred Bruder of SuCrest, Mr. George Spink of North
American Sugar, Dr. P. F. Meads of CSH, Mr. A. M. Bartolo of Imperial,
and Dr. J. C. P. Chen of Southdown.
159
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SECTION XIII
REFERENCES
1. Spencer, G. L., and Meade, G, p.. Cane Sugar Handbook. Ninth Edition,
John Wiley and Sons, New York, (1964).
2. Keller, A. G., and Huckabay, H. K., "Pollution Abatement in the Sugar
Industry of Louisiana," Journal Water Pollution Control Federation.
37, 7, (July 1960) .
3. Biaggi, N., "The Sugar Industry in Puerto Rico and Its Relation to
the Industrial Waste Problem," Journal Water Pollution Control
Federation, 40, 8, (August 1968).
4. An industrial Waste Guide to the Cane Sugar Industry, U. S. Depart-
ment of Health, Education, and welfare. Public Health Service
Publication 691, Washington, D.C., (1963).
5. "Policy on Subsurface Emplacement of Fluids by Well Injection," A
Policy Statement issued by the U.S. Environmental Protection Agency
with Accompanying "Recommended Data Requirements for Environmental
Evaluation of Subsurface Emplacement of Fluids by Well Injection,"
Washington, D.C., (February 1973).
6. Public Health Service Drinking Water Standards, Revised 1962. U.S.
Department of Health, Education, and Welfare, U.S. Public Health
Service Publication 956, Washington, D.C., (1962).
7. Serner, H.E., "Entrainment in Vacuum Pans," Sugar v Azucar, (January
1969) .
8. Personal Communication from F. C. Schaffer, (June 1973).
9." Bhaskaran, T. R., and Chakrabarty, R. N., "Pilot Plant for Treat-
ment of Cane sugar Waste," Journal Water Pollution Control Federa-
tion, (July 1966) .
10. State-of^-Art, Suqarbeet Processing Waste Treatment, Environmental
Protection Agency, Water Pollution control Research series 12060
DSI, (July 1971).
11. Complete Mix Activated Sludge Treatment of Citrus Process Wastes,
Environmental Protection Agency, Water Pollution Control Research
Series 12060 EZY, (August 1971).
12. Treatment of Citrus Processing Wastes, Environmental Protection
Agency, Water Pollution Control Research Series 12060, (October
1970) .
161
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13. Comparison of Barometric and Surface Condensers, Unpublished
paper by the U.S. Cane Sugar Refiners1 Association, (March 9,
1973) .
14. Tsugita, R. A., et.al., "Treatment of Beet Sugar Plant Flume Water,"
British Columbia Research Council, University of British Columbia,
(1964) .
15. Application for FSUOD Discharge to Delaware Estuary, Report
Submitted to Delaware River Basin Commission, by Amstar Phila-
delphia Refinery, (July 1972).
16. Baumert, G. S., Refinery wastes and Pollution Control, SSI, (1969),
17. Dennis, Warren H., A Statistical Analysis of the BODS and FSOD
Content of Intake and Discharge Water at Amstar Philadelphia
Refinery, Warf Institute, Madison, Wisconsin, (1973),
18. Guzman, Ramon M., "Control of Cane sugar Wastes in Puerto Rico,"
Journal Water Pollution Control Federation. 34, 12, (December 1962) .
19. Kemp, P. H., and Cox, S. M. H., Pollution and Pollution Abatement
in the Natal Sugar Industry, Proceedings of the 13th congress of
the International society of Sugar cane Technologists, (1969).
20. Oswald, William J., et.al.. Anaerobic-Aerobic Ponds for Treatment
of Beet Sugar Wastes, Proceedings, second National Symposium on
Food Processing Wastes, Denver, Colorado, (March 23-6, 1971) .
21. Pace, G. L., "Making cane Sugar for Refining," Chemical and Metal-
lurgical Engineering, 48, (July 1941).
22. Salley, George H., A Report on the Florida Sugar Industry, Private
Publication, (1967).
23. Shreve, R. N., Chemical Process Industries, Third Edition, McGraw-
Hill, New York, (1967),
24. Smith, Dudley, Where Puerto Rico Stands in Sugar, Paper Presented
to the Sugar Club of New York, (February 15, 1972).
25. South Florida Sugar Industry, Florida State Board of Health, Bureau
of Sanitary Engineering, Jacksonville, Florida, (1964).
26. Structure of the U.S. Cane Sugar Industry, U. S. Department of
Agriculture, Economic Research Service, (1972).
27. Sugar Manual, Hawaiian Sugar Planters1 Association, (1972),
28. Sugar Reports, U.S. Department of Agriculture, Agricultural stabi-
lization and Conservation Service, Washington, D.C., (1971).
162
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29. Sugar Statistics and Related Data, Volumes I and II, Revised, U.S.
Department of Agriculture, Washington, D.C., (February 1970).
30. "Development Document for Proposed Effluent Limitations Guidelines
and New source Performance Standards for the STEAM ELECTRIC POWER
GENERATING Point Source Category", U. S. Environmental Protection
Agency (March 1974).
31. "Development Document for Proposed, Effluent Limitations Guidelines
and New Source performance Standards for the CITRUS, APPLE AND
POTATO Segment of the canned and Preserved Fruits and Vegetables
Processing Point Source Category", 0, S, Environmental Protection
Agency (November 1973).
163
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SECTION XIV
GLOSSARY
Affination - Washing to remove the adhering film of molasses from the
surface of the raw sugar crystal, the first step in the refining
operation.
Affination Centrifugal - A high speed centrifugal which separates syrup
and molasses from sugar. Syrup from this centrifugal is recycled to the
mingling phase of refining.
Alkalinity - Alkalinity is
neutralize an acid.
measure of the capacity of water to
Alphanaphthol Test - A test for sucrose concentration in condenser
water. The method is based on a color change which occurs in the
reaction of the inorganic constituents.
Ash Content - In analysis of sugar products, sulfuric acid is added to
the sample, and this residue, as "sulfated ash" heated to 800°C is taken
to be a measure of the inorganic constituents.
Barometric Condenser - See Condenser, Barometric.
Barometric Leg - A long vertical pipe through which spent condenser
water leaves the condenser. Serves as a source of vacuum.
Barometric Leg water - Condenser cooling water.
Biological Wastewater Treatment - Forms of waste water treatment in
which bacterial or biochemical action is intensified to stabilize,
oxidize, and nitrify the unstable organic matter present. Trickling
filters, and activated sludge processes are examples.
Blackstrap Molasses - Molasses produced by the final vacuum pans, and
frdm which sugar is unrecoverable by ordinary means. Blackstrap is
usually sold for various uses.
BOD.5 - Biochemical Oxygen Demand is a semiquantitative measure of bio-
logical decomposition of organic matter in a water sample. It is deter-
mined by measuring the oxygen required by micro-organisms to oxidize the
contaminants of a water sample under standard laboratory conditions.
The standard conditions include incubation for five days at 20°C.
Boiler Ash - The solid residue remaining from combustion of fuel in a
boiler furnace.
Boiler Feedvrater - Water used to generate steam in a boiler. This water
is usually condensate, except during boiler startup, when treated fresh
water is normally used.
165
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Boiler Slowdown - Discharge from a boiler system designed to prevent a
buildup of dissolved solids.
Bone Char - An adsorptive material used in cane sugar refineries which
is utilized in the removal of organic and inorganic impurities from
sugar liquor.
Calandria - The steam belt or heating element in an evaporator or vacuum
pan, consisting of vertical tube sheets constituting the heating
surface.
Calandria Evaporator - An evaporator using a calandria; the standard
evaporator in current use in the sugar industry.
Calandria Vacuum Pan - A vacuum pan using a calandria;
vacuum pan in current use in the sugar industry.
the standard
Centrifugation - A procedure used to separate materials of differing
densities by subjecting them to high speed revolutions. In sugar pro-
cessing, centrifugation is used to remove sugar crystals from
massecuite.
Char Cistern - Cylindrical vats, measuring approximately 10 feet in
diameter by 20 feet deep, which contain approximately 40 tons of bone
char.
Clarification - The process of removing undissolved materials (largely
insoluble lime salts) from cane juice by settling, filtration, or
flotation.
Coagulation - In water and waste water treatment, the destabilization
and initial aggregation of colloidal and finely divided suspended matter
by the addition of a floe-forming chemical or by biological process.
COD - Chemical Oxygen Demand. Its determination provides a measure of
the oxygen demand equivalent to that portion of matter in a sample which
is susceptible to oxidation by a strong chemical oxidant.
Condensate - water resulting from the condensation of vapor.
Condenser - A heat exchange device used for condensation.
Barometric: Condenser in which the cooling water and the vapors
are in physical contact; the condensate is mixed
in the cooling water.
Surface: condenser in which heat is transferred through a
barrier that separates the cooling water and the
vapor. The condensate can be recovered separately.
Condenser Water - Water used for cooling in a condenser.
166
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Crystallization - The process through which sugar crystals separate from
ma Rs^rmi •(-«.
massecuite.
Decanting - Separation of a liquid from solids by drawing off the
layer after the heavier material has settled.
upper
Decolorization - The refining process of removing color from sugar. The
predominantly used methods involve the use of bone char, granular acti-
vated carbon, vegetable carbon, or powdered activated carbon.
Defecants - Chemicals which are added to melt liquor in order to remove
remaining impurities. They include phosphoric acid (or carbon dioxide)
and lime. The result of the treatment is the neutralization of organic
acids and formation of a tri-calcium phosphate precipitate which
entrains much of the colloidal and other suspended matter in the liquor.
Defecation Process - A method for purifying the cane juice involving
lime, heat, and a small amount of phosphate. The result is the
formation of an insoluble precipitate which is then removed in the
clarification process.
Demineralization - Removal of mineral impurities from sugar.
Dextrose - Glucose. An invert sugar with the formula C6H12O6.
is a minor component of raw sugar.
Dextrose
Diatomaceous Earth - A viable earthy deposit composed of nearly pure
silica and consisting essentially of the shells of the microscopic
plants called diatoms, Diatomaceous earth is utilized by the cane sugar
industry as a filter aid.
Pi s a cchar i de s - A sugar such as sucrose composed of two monosaccharides.
DiO... - Dissolved Oxygen is a measure of the amount of free oxygen in a
water sample. It is dependent on the physical, chemical, and
biochemical activities of the water sample.
" Effect1' - In systems where evaporators are operated in series of
several units, each evaporator is known as an effect.
Entrajnment - The entrapment of liquid droplets containing sugar in the
water vapor produced by evaporation of syrup.
Evaporator - A closed vessel heated by steam and placed under a vacuum.
The basic principle is that syrup enters the evaporator at a temperature
higher than its boiling point under the reduced pressure, or is heated
to that temperature. The result is flash evaporation of a portion of
the water in the syrup.
e Crystals - New sugar crystals which form spontaneously without the
presence of others. This event is undesirable, and therefore vacuum pan
conditions are maintained in a narrow range of sucrose concentration and
temperature which precludes their formation.
167
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Filter Cake - The residue remaining
produced by the clarification process.
after filtration of the sludge
Filter Mud - A mud produced by slurrying filter cake. The resultant
waste stream is a significant source of solids and organics within a
cane sugar refinery.
Filter Press - In the past the most common type of filter used to
separate solids from sludge. It consists of a simple and efficient
plate and frame filter which allows filtered juice to mix with clarified
juice and be sent to the evaporators.
Fixed Beds - A filter or adsorption bed where the entire media is
exhausted before any of the media is cleaned,
Flocculant - A substance that induces or promotes fine particles in a
colloidal suspension to aggregate into small lumps, which are more
easily removed.
Floorwash - Water used to wash factory or refinery floors and equipment.
Flotation - The raising of suspended matter to the surface of the liquid
in a tank as scum - by aeration, the evolution of gas, chemicals, elec-
trolysis, heat, or bacterial decomposition - and the subsequent removal
of the scum by skimming.
Frothing Clarifiers - Flotation devices that separate tri-calcium
phosphate precipitate from the liquor.
Furfural - An aldehyde C4H3OCHO used in making Furaw and as a resin.
Glucose - Dextrose.
GPD - Gallons per day.
GPM - Gallons per minute.
Granular Activated Carbon - Substance used for decolorization of sugar.
It differs from bone char in that it produces more sweet water, adsorbs
no ash, and is normally not washed. There is little waste water
produced from this process.
Granulation - The process which removes remaining moisture from sugar,
and also separating the crystals from one another.
Granulator - A rotary dryer used in sugar refineries to remove
moisture from sugar crystals prior to packaging or storing.
free
Hvdrolization - The addition of H2O to a molecule. In sugar production,
hydrolization of sucrose results in an inversion into glucose and
fructose and represents lost production.
168
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Impoundment - A pond, lake, tank, basin, or other space which is used
for storage of waste water.
Impurities - Fine particles of bagasse, fats, waxes, and gums contained
in the cane juice after milling. These impurities are reduced by
successive refining processes.
Invert Sugars - Glucose and fructose formed by the splitting of sucrose
by the enzyme sucrase.
Ion exchange - Reversible exchange of ions contained in a crystal for
different ions in solution without destruction of crystal structure or
disturbance of electrical neutrality. Used in sugar refining for color
removal or removal of impurities.
Ion Exchange Resins - Resins consisting of three-dimensional networks to
which are attached ionizable groups.
Isomers - Two or more compounds containing the same elements and having
the same molecular weights, but differing in structure and properties,
e.g. glucose and fructose.
Juices
clarified: The juice obtained as a result of the clarification
process, and synonymous with evaporator supply when
the filtered juice is returned to the mixed juice.
Mixed: The juice sent from the extraction plant to the
boiling house.
Leyulose - Fructose. An invert sugar composed of six carbon chains with
the formula C(5H12O6. Levulose is a component of raw sugar.
Magma - A heated sugar syrup solution to which raw crystals have been
added.
Magma mingler - A revolving coiled mixer in which magma is heated in
order to facilitate loosening the molasses film from raw sugar crystals;
the first step in the refining process.
Massecuite - Mixture of sugar crystals and syrup which originates in
the boiling of the sugar (literally cooked mass) .
a small amount of
Liquor - Molten sugar to which has been added
water (half the weight of the sugar) .
MGD - Million gallons per day.
mg/1 - Milligrams per liter (equals parts per million, ppm, when the
specific gravity is unity) .
Moisture - Loss in weight due to drying under specified conditions,
expressed as percentage of total weight,
169
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Molasses - A dark-colored syrup containing non-sugars produced in
processing cane and beet sugar.
Monosaccharides - Simplified form of sugar.
Moving Beds - A filtration or adsorption bed where the media is con-
stantly being removed and fresh media added.
Mud - The precipitated sludge resulting from the clarification process.
Multiple Effect Evaporation - The operation of evaporators in a series.
Nutrients - The nutrients in contaminated water are routinely analyzed
to characterize the food available for micro-organisms to promote
organic decomposition. They are:
Ammonia Nitrogen (NH3), mg/1 as N
Kleldahl Nitrogen (ON), mg/1 as N
Nitrate Nitrogen (NO3), mg/1 as N
Total Phosphate (TP), mg/1 as P
Ortho Phosphate (OP), mg/1 as P
pH - pH is a measure of the negative log of hydrogen ion concentration.
Phases of Supersaturation - metastable phase in which existing sugar
crystals grow but new crystals do not form; the intermediate phase in
which existing crystals grow and new crystals do form; and the labile
phase in which new crystals form spontaneously without the presence of
others.
Plate and Frame Filter - A filtering device consisting of a fastened
inside a metal frame.
POL - The value determined by single polarization of the normal weight
of a sugar product made up to a total volume of 100 milliliters at 20°C,
clarified when necessary, with dry lead subacetate and read in a tube
200 milliliters long at 20°C, using the Bates-Jackson saccharimeter
scale. The term is used in calculations as if it were a real substance.
go1yelectrolytes - Coagulent aids consisting of long chained organic
molecules.
Precoat Filter - A type of filter in which the media is applied to an
existing surface prior to filtration.
Raw Sugar - An intermediate product consisting of crystals of high
purity covered with a film of low quality syrup.
Recrvstallization - Formation of new crystals from previously melted
sugar liquor. Recrystallization is encouraged by evaporators and accom-
plished in vacuum pans.
170
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Regeneration Kilns - - Ovens which operate with a controlled amount of
air, and in which bone char is placed for renewal of its capacities for
buffering and decolorizing.
Regeneration of char - After some sixty hours of operation, the de-
colorizing ability of bone char decreases to an unacceptable level, and
the char must be washed and regenerated by heat in kilns or char house
furnaces.
Remelt - A solution of low grade sugar in clarified juice or water.
Resorcinol Test - A color indicator test for determining the concen-
tration of sucrose in condensate and condenser waters.
Rotary Vacuum Filter - A rotating drum filter which utilizes suction to
separate solids from the sludge produced by clarification.
Saturation - The use of water in the milling process to dissolve
sucrose. Identical, in this connotation, with imbibition and macer-
ation.
§§!
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Strike * The massecuite content of a vacuum pan.
Sucrose - A disaccharide having the formula C12H22O11. The terms
sucrose and sugar are generally interchangeable, and the common sugar of
commerce is sucrose in varying degrees of purity. Refined cane sugar is
essentially 100 percent sucrose.
Sugar - The sucrose crystals, including adhering mother liquor,
remaining after centrifugation.
Commercial:
Low Grade:
96 DA:
Sugar from high grade massecuite, which enters into
commerce.
Sugar from low grade massecuite, synonymous with
remelt sugar.
A value used for reporting commercial sugar on a
common basis, calculated from an empirical formula
issued by the United States Department of Agri-
culture.
Supersaturation - The condition of a solution when it contains more
solute (sucrose) than would be present under normal pressure and temp-
erature. When equilibrium is established between the saturated solution
and undissolved solute, crystal growth commences.
Surface condenser - see condenser. Surface.
Suspended Solids - solids found in waste water or in the stream which in
most cases can be removed by filtration. The origin of suspended matter
may be man-made wastes or natural sources as from erosion.
Vapor - Steam liberated from boiling sugar liquor.
vapor Belt - The distance between the liquid level in an air evaporator
or vacuum pan and the top of the cylindrical portion of the body.
Vegetable Carbon - A media for sugar decolorization.
Waste Streams - Any liquid waste material produced by a refinery.
172
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METRIC UNITS
CONVERSION TABLE
-j
to
MULTIPLY (ENGLISH UNITS)
ENGLISH UNIT ABBREVIATION
acre ac
acre - feet ac ft
British Thermal BTU
Unit
British Thermal BTU/lb
Unit/pound
cubic feet/minute cfm
cubic feet/second cfs
cubic feet cu ft
cubic feet cu ft
cubic inches cuin
degree Fahrenheit °F
feet ft
gallon gal
gallon/minute gpm
horsepower hp
inches in
inches of mercury in Hg
pounds lb
million gallons/day mgd
mile mi
pound/square inch psig
(gauge)
square feet sq ft
square inches sq in
tons (short) ton
yard yd
by
CONVERSION
0.405
1233.5
0.252
0.555
0.028
1. 7
0.028
28.32
16.39
0.555 (°F-32)*
0.3048
3.785
0.0631
0.7457
2.54
0.03342
0.454
3,785
1.609
(0.06805 psig +1)*
0.0929
6.452
0.907
0.9144
TO OBTAIN (METRIC UNITS)
ABBREVIATION METRIC UNIT
ha hectares
cu m cubic meters
kg cal kilogram-calories
kg cal/kg kilogram calories/
kilogram
cu m/min cubic meters/minute
cum/rain cubic meters/minute
cu m cubic meters
1 liters
cu cm cubic centimeters
°C degree Centigrade
m meters
1 liters
I/sec liters/second
kw kilowatts
cm centimeters
atm atmospheres
kg kilograms
cu in/day cubic meters/day
km kilometer
atm atmospheres
(absolute)
sqm square meters
sq cm square centimeters
kkg metric tons
(1000 kilograms)
m meters
*Actual conversion, not a multiplier
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