EPA 440/1-73/005
Development Document for Proposed
Effluent Limitations Guidelines
and New Source Performance Standards
for the
CEMENT
Manufacturing Point Source Category
\
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
AUGUST 1973
-------
Publication Notice
This is a development document for proposed effluent
limitations guidelines and new source performance standards,
As such, this report is subject to changes resulting from
comments received during the period of public comments
of the proposed regulations. This document in its final
form will be published at the time the regulations for
this industry are promulgated.
-------
DEVELOPMENT DOCUMENT FOR
EFFLUENT LIMITATIONS GUIDELINES
AND STANDARDS OF PEPFORMANCE
CEMENT MANUFACTURING CATEGORY
John Quarles
Acting Administrator
Robert L. Sansom
Assistant Administrator for Air & Water Programs
Allen Cywin
Director, Effluent Guidelines Division
John Riley
Project Officer
September, 1973
Effluent Guidelines Division
Office of Air and Water Programs
U.S. Environmental Protection Agency
Washington, D. C. 20460
Environmental Protection Agency
Li IT': ":, ''. v^lon V
1 l^nh ">V?-,;;c^r Brive
Chicago, Illinois 60606
-------
-------
ABSTRACT
This report presents the findings of a study of the cement manufacturing
industry by Southern Research Institute for the Environmental Protection
Agency for the purpose of developing effluent limitation guidelines
setting forth the degree of effluent reduction attainable through the
application of the best practicable control technology currently
available and the degree of effluent reduction attainable through the
application of the best available technology economically achievable
which must be achieved by existing plants by July 1, 1977 and July 1,
1983 respectively; and standards of performance; and pretreatment
standards for the industry — setting forth the degree of effluent
reduction achievable through the application of the best available
demonstrated control technology, processes, operating methods, or other
alternatives — to implement Sections 304, 306, and 307 of the Federal
Water Pollution Control Act, as amended.
Nonleaching plants can achieve essentially no discharge of pollutants by
July 1, 1977 through the implementation of technology consisting of
recycling and reuse, or isolation of cooling water from possible
contamination and containment of runoff from kiln dust piles. This
technology also applies to 1983 limitations and standards for new
sources, and to the nonleaching streams at. leaching plants. For
leaching streams, the recommended limitations for 1977 are a pH of 6.0
to 9.0 and suspended solids of not more than 0.15 kg/kkg (0.30 Ib/t) of
dust leached achievable by neutralization and sedimentation.
Elimination of dissolved solids by 1983 will require the transfer of
treatment technology from other industries.
Supporting data and rationale for the development of the proposed
guidelines and standards are contained in this report.
-------
CONTENTS
Section Page
I Conclusions 1
II Recommendations 3
Best Practicable Control Technology 3
Currently Available
Best Available Technology 3
Economically Achievable
New Source Performance Standards 3
III Introduction 5
Purpose and Authority 5
Basis for Guidelines Development 6
Description of the Cement Manufacturing 14
Industry
Description of the Manufacturing Process 16
Kiln-Dust Considerations 20
IV Industry Categorization
Introduction 25
Factors Considered 25
V Water Use and Waste Characterization 33
General 33
Specific Water Uses and Waste 33
Characteristics
VI Selection of Pollutant Parameters 41
Definition of Pollutants 41
Parameters Selected as Pollutants 41
Rationale for Selection of Specific 42
Parameters as Pollutants
Rationale for Rejection of Specific 45
Parameters as Pollutants
111
-------
CONTENTS
Section
VII
VIII
IX
X
XI
Control and Treatment Technology 49
Introduction 49
In-Plant Control Measures 50
Treatment Technology 52
Description of Plants That Demonstrate 60
Control and Treatment Technology
Cost, Energy, and Nonwater Quality Aspects 73
Cost and Reduction Benefits of Alternative 73
Control and Treatment Technologies
Effects of Costs on the Industry 79
Energy Requirements 79
Nonwater Quality Aspects 79
Effluent Reduction Attainable Through 87
Application of the Best Practicable
Control Technology Currently Available;
Effluent Limitations Guidelines
Introduction 87
Identification of BPCTCA 88
Rationale for Selection of BPCTCA 89
Effluent Reduction Attainable Through
The Application of the Best Available 93
Technology Economically Achievable;
Effluent Limitations Guidelines
Introduction Q3
Identification of BATEA
Rationale for Selection of BATEA 9.,
New Source Performance Standards and 97
Pretreatment Standards
New Source Performance Standard 97
Pretreatment Standards 97
IV
-------
CONTENTS
Section Page
XII Acknowledgments 99
XIII References 101
XIV Glossary 105
Definitions and Terminology 105
Conversion Factors HI
-------
FIGURES
PAGE
1 Waste Water Survey Questionnaire ,s
2 Sample Data Sheet 11
3 Geographical Distribution of 15
Operating Cement Plants
4 Flow Sheet for the Manufacture IQ
of Portland Cement
5 Kiln Dust Collection and Handling 22
6 Comparison of Loading of Selected 27
Parameters for Leaching and Non-
leaching Plants
7 Diagram of Water Usage in Cement 36
Manufacturing
8 Distribution of Reported Maximum pH 44
9 Distribution of Calculated Average 46
Temperature Rise
10 Solubility of Calcium Carbonate as 53
a Function of pH
11 Diagram of Electrodialytic Treatment 55
of Leachate
12 Flow Sheet for the Recovery of 61
Potassium Sulfate from Kiln Dust
13 Diagram of Water-Management Plan for 62
Plant A
14 Diagram of Water-Management Plan for 64
Plant B
15 Diagram of Water-Management Plan for 66
Plant C
VI
-------
FIGURES (continued)
PAGE
16 Diagram of Water-Management Plan for 57
Plant D
17 Diagram of Water-Management Plan for 69
Plant G
18 Diagram of Water-Management Plan for 70
Plant H
Vll
-------
TABLES
PAGE
1 Summary of Features of Plants 10
Studied
2 Distribution of Plants by Reported 12
Loading for 18 Parameters
3 Comparison of Reported and Measured ^3
Waste Loads at Plants Visited
4 Distribution of Portland Cement ^7
Plants by Capacity
5 Summary of Methods of Dust 23
Utilization and Disposal
6 Comparison of Loadings of Selected 28
Parameters for Wet- and Dry-
Process Plants
7 Comparison of Loadings and Water 39
Discharged for Plants of
Different Capacity
8 Comparison of Loadings for Leaching 34
and Nonleaching Subcategories
9 Summary of Water Usage for the 35
Cement Manufacturing Industry
10 Reported Cooling Water Usage in 37
Cement Plants
11 Loadings of Pollutant Parameters for 43
Leaching and Nonleaching Plants
12 Water Effluent Treatment Cost and 74
Pollution Reduction Benefits
13 Plant Production Costs 78
14 Table of Conversion Factors 11;L
Vlll
-------
SECTION 1
CONCLUSIONS
For the purpose of establishing effluent limitations guidelines and
standards of performance for new sources, the cement manufacturing
industry is divided into two subcategories: leaching plants (those that
use water in contact with kiln dus-t as an integral part of the process
as in the leaching of dust for reuse or wet scrubbing to control stack
emissions), and nonleaching plants.
Process waste water pollutants are those constituents of discharged
water that are added in measurable quantities (greater than 0.005 kg/kkg
(0.01 Ib/t) of product) as a result of the water being used in
manufacturing operations characteristic of the industry.
Presently about 35 of 154 nonleaching plants are achieving essentially
no discharge of pollutants; that is, they are discharging less than
0.005 kg/kkg (0.01 Ib/t) of product not including runoff. The remaining
119 plants can also achieve essentially no discharge of pollutants by
July 1, 1977.
For the approximately 12 plants in the leaching subcategory, substantial
reduction in suspended solids and pH can be achieved by July 1, 1977
with existing technology. However, elimination of dissolved solids by
July 1, 1983 will require the adaptation of additional treatment
technology by the industry.
It is estimated that the costs of achieving the limitations and
standards for 1977 by all plants in the industry is less than
$30,000,000. As a result of implementing the 1977 limitations and
standards, the increased cost of producing cement is estimated to range
from 0.6 to 0.9 percent.
The cost of the additional treatment technology required for plants
currently leaching to meet 1983 limitations and standards is less than
$U,000,000. As a result of implementing the 1983 limitations and
standards, the increased cost of producing cement is estimated to range
from 0.6 to 0.9 percent above the costs required to meet 1977
limitations and standards.
-------
SECTION II
RECOMMENDATIONS
Best Practicable^Control Technology Currently Available
For plants in the nonleaching subcategory, essentially no discharge of
pollutants in manufacturing effluents is recommended as the limitation
except for temperature where an increase of 3°C is recommended as the
limitation. This represents the degree of effluent reduction obtainable
by existing plants by July 1, 1977 through the application of the best
practicable control technology currently available.
The technology on which this limitation is based consists of isolation
of cooling water from possible contamination, and recycling or reuse of
other water (including cooling water if not isolated).
Disposal sites for kiln dust should be designed to prevent runoff, or
where such runoff cannot be prevented, it should be treated by
neutralization and sedimentation. Material storage piles should be
suitably diked to prevent the discharge of pollutants to navigable
waters if a 10 year, 24 hour rainfall event occurs.
For plants in the leaching subcategory, the degree of improvement in
effluent quality that is achievable through application of the best
practicable control technology currently available is the same as those
for plants in the nonleaching subcategory for all except the dust-
contact streams where reduction of pH to 9.0 and suspended solids to
0.15 kg/kkg (0.30 Ib/ton) of dust leached is recommended as the effluent
limitation.
The technology on which the limitation for leaching streams is based
consists of segregation of dust-contact streams and neutralization with
stack gases followed by sedimentation.
ggst^Ayailable^TechnglogY^Economically^Achievable
Essentially no discharge of pollutants is recommended as the effluent
limitation for nonleaching plants and leaching plants to be achieved by
July 1, 1983.
New Spurce^Performance Standards
For leaching plants, this limitation is based on the use of processes
shown to be feasible in other industries for reducing the dissolved
content in the leachate stream, and recycling the stream. One such
-------
process is electrodialysis, which has been used for more than a decad.».
in Japan for concentrating seawater to produce brines. tne definition
of Best Available Technology Economically Achievable, the necessar\
technology is available, but may require some development work to adapt
to this application.
The effluent reduction attainable through the application of the belt
available demonstrated control technology is essentially no discharge :f
pollutants for nonleaching plants and for the nondust contact streams at
leaching plants. For the dust contact streams at leaching plants
reduction of suspended solids to less than 0.15 kg/kkg (0.30 Ib/ton) of
dust leached is attainable These are the standards recommended for new
plants and are based on the application of the technology described as
Best Practicable, Currently Available. As the technology described as
Best Available, Economically Achievable is developed and demonstrated,
the performance standards for new leaching plants should be revised to
reflect the recommendation of essentially no discharge of pollutants*
-------
SECTION III
INTRODUCTION
Purpose^ and Authority
Section 301(b) of the Act requires the achievement by not latur than
July lf 1977, of effluent limitations for point sources, other than
publicly 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(b) also requires the achievement by not later than July 1, 1V83, of
effluent limitations for point sources, other than publicly own .vd treat-
ment works, which are based on the application of the best available
technology economically achievable which will result in reasonable
further progress toward the national goal of eliminating the iischarge
of all pollutants, as determined in accordance with regulations issued
by the Administrator pursuant to Section 304(b) of the Act. Section 306
of the Act requires the achievement by new sources of a Federal standard
of performance providing for the control of the discharge of \ollutants
which reflects the greatest degree of effluent reduction which the
Administrator determines to be achievable through the application of the
best available demonstrated control technology, processes, operating
methods, or other alternatives, including, where practicable, a standard
permitting no discharge of pollutants.
Section 304(b) of the Act requires the Administrator to publish within
one year of enactment of the Act, regulations providing guidelines for
effluent limitations setting forth the degree of effluent reduction
attainable through the application of the best practicable control
technology currently available and the degree of effluent reduction
attainable through the application of the best control measures and
practices achievable including treatment techniques, process and
procedure innovations, operation methods and other alternatives. The
regulations proposed herein set forth effluent limitation1, guidelines
pursuant to Section 304 (b) of the Act for the cement Manufacturing
source category.
Section 306 of the Act requires the Administrator, within me year after
a category of sources is included in a list published pursuant to
Section 306(b) (1) (A) of the Act, to propose regulations establishing
Federal standards of performances for new sources within such
categories. The Administrator published in the Federal Register of
January 16, 1973 (38 F.R. 1624), a list of 27 source categories.
Publication of the list constituted announcement of the Administrator's
intention of establishing, under Section 306, standards of performance
applicable to new sources in the cement manufactturing -ource category,
which was included within the list published January 16, 1973.
-------
Basis for Guidelings Development
The effluent limitations guidelines and performance standards
recommended in this report were developed from analysis af Corps of
Engineers discharge permit applications and questionnaires to identify
potential subcategories, and exemplary plants, and obtain information on
water use and waste water characteristics. Furthert on-site studies of
potential exemplary plants were conducted to verify \his information and
observe control and treatment technology employed. Also, discussions
were held with consultants and others knowledgable of the manufacturing
and waste treatment practices in the industry.
General information was obtained on all plants and detailtsd information
was collected for 132 (80%) of the 166 domestic cem
-------
- Identification of distinguishing features that could
potentially provide a basis foi subcategorization of
the industry. These features included method of dust
collection and disposal, type of process, raw materials,
plant size and age, and others, discussed in detail in
Section IV.
- Determination of the water usage and waste character-
istics for each subcategory, discussed in Section V,
including the volume of water used, the sources of con-
tamination in the plant, and the type and quantity of
constituents in the wastewaters.
- Identification of those constituents, discussed in
Section VI, which are characteristic of the industry
and present in measurable quantities, thus being pol-
lutants subject to effluent limitations guidelines and
standards.
The results of this analysis, shown in Table 2, indicated that at least
20% of the plants in the industry are currently achieving essentially no
discharge of pollutants, that is, they are discharging less than 0.005
kg/kkg (0.01 Ib/ton) of product which corresponds to about 1 mg/1, the
minimum measurable concentration at the flow rates common in this
industry. The reliability of the reported RAPP data was verified by
sampling and analysis at ten plants. The average measured and reported
loadings of seven nonleaching plants and three leaching plants are shown
in Table 3. With the exception of dissolved solids at leaching plants,
the deviation of either measurement from the mean of the
-------
10. Water usage information:
In the table below indicate the source and daily amount (surface water, municipal, etc.) of
intake water and the fate and daily amount (surface containment, surface streams, evaporation, etc.) of
discharged water for each use. For recycled water, indicate makeup amount only under "Source" and esti-
mate total amount of water that would be consumed without recycling in Question No. ]1. For water that
is reused for another purpose, indicate previous usage under "Source" and subsequent use under "Fate".
For example, if cooling water is reused as slurry water, "Fate" for "cooling" is "slurry" and "Source"
for "slurry" is "cooling".
Intake
Use Source Amount, gpd
Boiler feed
Bearing cooling water
Cement-cooler water
Sanitary
Process (Slurry)
Dust leaching
Dust control
Quarry dewa taring
Contact clinker cooling
Raw material washing and
beneficiation
Other
(specify)
Total intake
Discharge Check if
treated before
Fate Amountj gpd discharge
D
n
D
D
D
D
n
n
n
n
n
Total discharge
11. Describe quantity and use of any water that is recycled
12. Types of kiln-dust collection system(s) used:
I~JCyclones [ [wet scrubbers
| |Bag houses [ ] None
[ [Precipitators [ [other (specify)
13. Estimated or designed kiln-dust collection efficiency: ______
14. Disposition of collected kiln-dust:
(a) Returned to kiln: tons/day; alkali content %
(b) Not returned to kiln: tons/day; alkali content %
15. Method of disposal: [ ]Surface piling | ) Return to quarry
[ | Utilized in some way (specify)
f~] Other (specify)
Figure 1 (continued). Wastewater Survey Questionnaire
-------
10. Water usage information:
In the table below indicate the source and daily amount (surface water, municipal, etc.) of
intake water and the fate and daily amount (surface containment, surface streams, evaporation, etc.) of
discharged water for each use. For recycled water, indicate makeup amount only under "Source" and esti-
mate total amount of water that would be consumed without recycling in Question No. 11. For water that
is reused for another purpose, indicate previous usage under "Source" and subsequent use under "Fate".
For example, if cooling water is reused as slurry water, "Fate" for "cooling" is "slurry" and "Source"
for "slurry" is "cooling".
Intake Discharge Check if
treated before
Use Source Amount, gpd Fate Amount, gpd discharge
Boiler feed | )
Bearing cooling water I |
Cement-cooler water | j
Sanitary | j
Process (Slurry) | |
Dust leaching | j
Dust control | ]
Quarry dewatering | |
Contact clinker cooling | )
Raw material washing and i—i
benef iciation | |
Other
(specify)
Total intake Total discharge
11. Describe quantity and use of any water that is recycled
12. Types of kiln-dust collection system(s) used:
I~J Cyclones [ J Wet scrubbers
[ | Bag houses [ ~JNone
fIPrecipitators I[other (specify)
13. Estimated or designed kiln-dust collection efficiency:
14. Disposition of collected kiln-dust:
(a) Returned to kiln: tons/day; alkali content
(b) Not returned to kiln: tons/day; alkali content
15. Method of disposal: [ ]Surface piling | 1 Return to quarry
IjUtilized in some way (specify)
Other (specify)
Figure 1 (continued). Wastewater Survey Questionnaire
-------
DRAFT
TABLE 1
Summary of Features of Plants Studied
Features Number of Plants
Type of Process
Method of Dust Collection and Disposition
All returned to kiln 3
Leach 3
Surface pile or quarry 8
Wet slurry 1
Wet scrubber 1
Plant Age
Built before 1920 4
1920 to 1939 3
1940 to 1959 4
1959 to present 4
Plant Capacity , Thousand metric tons/year
450 or less 4
450 to 900 9
Over 900 1
Raw Materials
Limestone 10
Marl 2
Oyster Shell 3
Type of Primary Fuel
Gas 10
Coal 3
Oil 2
Plant Location
Northeast 3
South 4
Midwest 4
West 4
-10-
-------
DRAFT
UJ
Q
0
U
ac.
i/>
Z
o
13
UJ
or
gf
Q.
OJ
UJ
0
o
a
a
Or
z
o
*-*
^_
^
{j
o
J
Q
Z
4f
UJ
s:
iif
z
•
I—
Z
<:
_ i
a.
0
z
^
>-
z
^
a.
5,
O
U
in
o
CD
in
in
-t
O
r-
CM
in
X
o
o
a>
o
or
lu
\s
Z
•_•
-J
IJ
0
u
1—
z
Ul
31
Ul
u
y/
U
O
fj^
0
UJ
m
or
« Z -I -1
5t J UJ <
— — 3 O
oc ^ u. u
a.
m uj >- uj
-J Z < DC
*< O — 1 O
3 -• 1- (J
QC UJ UJ O
i- z: or
z: -J
m
in
Ul UJ l—
a. u. u uj
>- 0 O 3
t- ac.
a
z
o >-
>- 1- Q O
_l U ^ O
•— 3 m *-<
«t a Z (M
Q O O
a
or
uj in
tn u. z io
z: o _i
Z ii
m
UJ
fV (^J
Ul >- O
CD U. O O
Z O -1
3 a
z :E
Ul
>- oc
t— >- •
t- ~ ^ 0
z w in in
< < z r-
_i a o
a. < H-
o }£
0
> Ul
i— >-
*-• *t
Q _l u
Ul «- •—
<- U Q
or < z
o u. -.
a.
UJ 1- l/l
o at z -•
UJ UJ
o ui s: a:
or or i- ui
< < < i—
X UJ <
u a a: s
m ja i-
•— uj < < m
•-•1-133
«t 1— UJ Ul
z 3 f- or
•-• or m
i- uj < a:
i- u I 3 o
•" 1- O u» 13
3 Z < Z
m o m i »-
U 1— _l
1- — l- U
z »- z z >-
< u) or < o
-J 3 UJ _J UJ
a Q a a or
a
UJ
i—
u.
UJ
o
DC
r
o
i
z
0
z
to
a
z
Ul
i—
^
Q_
OJ
Ul
o
or
^
i
t/)
»-«
Q
o
O.
O
5;
«.
LU
O
iy>
D
£T
LU
<(
^
a
a.
s.
«,
UJ
«3;
1—
Z
,_•
or
UJ
H-
«^
3
PORATION 0.100
SUMPTJON 0.520
< z
> o
UJ l*J
O O O O CO
O O O O
s. t- a "i 2.
UJ Z i/> 5" <
f- z « or ui
« z Q — or
in z Q m
u z ui
Ul 3 U Ul
l- O Z -I
m uj or < cc
< u o »- <
3 < or ex. o
U- Ul UJ —
z or Q u >
3 3 Z U <
z m 3 < z
o o o o o
*O O rxj o O
•-« o in r-i o
(M O O O O
Cl UJ
U- >- ui
o m or 3
z or m <
•-• ui uj i— a;
_J _J l-J —• UJ
o — o z I
o o or < t-
u CD a. in o
o o o o
o *o o o
r-« r-« O O
• • • •
O r\J O O
ui or m
u uj or ui
o: t- uj u
3 < i- or
0 3
*
oo in
oj xO
0 ^
rj
z
o
UJ V-
O *-v
o: -J
X t3
O *
01 UJ
•-« o
Q a
<^
_J T
•< U
1- U)
O ~
1— ti
O
CO
f"
r\j
UJ
ifl
^3
_j
^
!„
O
l_
^
O NC
\O Is-
oj o
• <—*
f^J
2;
o
UJ K-
«t _J
^
— o
0 0
Z a\ o O
•- • o o
o o o
o
o
• o o
O 0 O
CO
CD
CO CM f-
• O CM
000
o
•0
CM o in
• 0 CM
0 0 CD
o
co
• fO •-«
-> 0 O
o in
o a t-
z o z
z: uj
J UJ •
3 f. 0
3 Q Z tx
I- O 3
CD K in
^ a
• u.
m o
y
< Z r-
uj O or m
ui »-•
UJ O_ 3
n
^
ID
i—i
> •
< or o
Z UJ O
Z CM
0 Z 0^
1-30
>- t/J r\i
t- <
n o
a.
Z ct
.-« UJ
a *
_j «: o
< LU O
s: »— -*
D^ ^ O
uj •—• CN
>v-
co ao O
r^ oj O
<7« O* O
* * •
rH c-t O
«/->
Q S
a <
|J) i/) UJ
5; 2:0;
» <. »-
< UJ tO
i- or
< h~ uj
O lO t- i- or
< O O H-
~Z t- 1- t/>
NDICATES .001 LB)
t-f
l
+.
**,
t-~
(_^
^
o
or
a
u.
O
0
i —
v^
3J
—1
Cl
2!
oj;
>-
.
00
_J
y
c^.
U)
1-
<
(—
ZJ
_J
_J
o
a
u_
o
CJ
P*
n
a
.
f-
i^I I— < r-4
Z in r-»
•—• • rH
_J 10 »
-€ Ki 0
V CM
<5^
X Z
< 0
O I—
or or
Ul UJ
a a
(Jv
• •
OD rg
r x
a <
UJ
X cv
< i-
?" m
SULFIDE *PHENOLS *CMKOMJUM
**«•*•«*** 0.00 0.00
*****»»»» U.ouO u.ooo
UJ CM O
t- o o
^ • >o
U~ O1* •
_i r- o
3 (M
m •-<
UJ O O
•- • ->
or. o •
o ::>
1
X
o
I/)
cr if\ o
O co O
• o
IjS r-( *
O
_l
»— •
o
iO O O
CC O f J
r • o
a. o •
/) O
0
r
a.
moo
O 0 0
2 • 0
O •
w') O
^
^
^
Ul t^~ U^
o t-« t-^
O « 0
ff •-» •
»- xf 0
^
^
>~ iT
< 6
PC IK
UJ UJ
a o
. t
4-J
d)
(U
rCl
f ft
UJ
15
_JJ
03
Q
_,
^u
. — i
PJ
S
(T<
CO
•
r\]
N
(D
^i
^j
hv
O
-H
ft i
l-M
-11-
-------
TABLE 2
DISTRIBUTION OF PLANTS BY REPORTED LOADING FOR 18 PARAMETERS
Alkalinity
BOD
COD
Total solids
Dissolved solids
Suspended solids
Volatile solids
Ammonia
Kjeldahl nitrogen
Nitrate as N
Phosphorus
Oil and grease
Chloride
Sulfate
Sulfide
Phenols*
Chromium*
Potassium
Number of
Plants
Reporting
78
74
69
79
77
75
73
69
67
69
71
56
67
68
50
56
62
15
waste Load, kg/k*
Less
than
.005
44
59
40
28
27
35
34
69
65
66
71
51
48
36
50
52
55
7
.OU5
to
.049
8
14
17
15
11
13
13
0
1
3
0
3
6
11
0
1
2
1
• w 3
to
.49
15
1
12
11
19
18
15
0
1
0
0
2
9
10
0
3
4
3
;g
0.5
to
4.9
11
0
0
13
8
8
11
0
0
0
0
0
4
10
0
0
1
3
Greater
than
5
0
0
0
12
12
1
0
0
0
0
0
0
0
1
0
0
0
1
*Load expressed in g/kkg.
-12-
-------
o
P
rt
to
Cu
CD
H
P-
*xf
*ti
T) cn
0 C.
rt M
CU Mi
co to
cn rt
p- fo
£
3
O
o
o
1 M
y*^
p
1 0
o
10
^^
o o
• •
p O O
'O CD C3
x) M cn
h-1
M* s~\
n o
Co
rt O
P- M
O NJ
3 **^
cn
Ml
0 0
1-1
1 O
I-1 O
O CO
T3 y^
M O
P
3 1 O
rt o
cn ^-J
• v_y
1 +
O
•
1 O
o
to
cn
c
cn
*o
m
3
a.
ro
cu
C/J
o
p-
Cu
cn
O
O
0
O
x—s
o
•
o
t— 1
oo
^y
o
o
ho
to
s~^
o
o
-e-
x_/
o
•
0
I-1
Ul
/-»N
o
o
co
h- '
^w*
1+
o
•
o
o
<3\
O
p-
cn
cn
o
i — i
<5
fo
cu
cn
0
I »
p-
Cu
cn
O
0
10
vo
f*^
O
•
0
Ul
Oo
o
o
CO
ro
^-^
o
o
CTv
v-y
o
o
o
* — \
o
o
o^
( — >
"^^
1+
•
o
o
to
5>
1 — '
F?
Cu
1 — 1
p-
3
H-
rt
^
ITJ
(U
1-1
cu
9
n>
rt
ro
O
o
o
y-^
o
•
cr1
•^
^d
^
CO
3
rt
CO
o
o
N^s
o
o
o
J— J
^•^
o
o
o
c/>
po
M
cn
rt
Cu
Mi
Mi
to
o
o
o
H-
^-^
o.
0
£p»
^
ro
1-1
cu
Jo
ro
o
to
*~^
'4
o
o
o
^
i-i
0
CU
C
o
rt
70
n
*o
0
1-1
rt
(0
Cu
s;
ro
cu
cn
C
i-i
ft>
Cu
D-
"^
ft)
ro
Sx)
ro o
Cu H
CO rt
C fD
fD
{*}. 03
3
?r MI
00 i-t
~-. 0
97*
oo 2
ro
0 (B
Ml 3
pg*
ro
CU
3
O
Ml
>
^
ro
i-i
P
w
fD
^
P
CO
rt
ro
"2
tr1 o
O 3
to i-.
Cu fD
cn p
• o
£j*
Jf p*
30 3
--.K
^7* *tj
30 !-•
x^~^ 3
I—1 rt
o* cn
•^^
rt s-^.
O — 1
3 ^™**
Sw'
O
Ml
^d
h<
0
CU
C
n
1 1
O
ro
p-
P
rt
p-
o
3
f}
O
S
p>
^j
M
CO
O
5S
CO
o
M
fi
ixJ
O
H
M
0
ft>
^
M H
Jl> ^*
Cn cfl
G r1
g M
1
1
o
•
oo
oo
Ul
^ — *
i — »
•
-j
^^
i
i
i
o
•
o
.0
1 Ui
/— ^
o
1
o
^£3
N_^
M O
• "
0 0
ON J>
Ui
^ — »
to /"%
o
1 — ' *
10 O
,^.
o
*
o
•£>
1 LA
s~\
o
I
1 0
VD
'i
•
0
1 0
o
Ul
•
^\
Ul
,^^
1 — >
I-1
CO
o
**~s
to
•
vo
oo
y,^^
L/l
•
VO
•2
JS
«
u>
r-o
/-^
00
•
O^
LO
^^
^
•
U3
_p>
M
*
O
VO
,— ^
N3
•
) — t
cr*
^
*rl
i — i
P
3
rt
cn
00
^^
M
•
ro
^— »
X— s
to
•
-P-
CO
5cj
M
cn
rt
P
Ml
Ml
H- •
•
I—1
Ul
y-^
to
•
CO
O
Jj>
P
3
rt
cn
,^
Co
^ ~
H"*
0*
rt
O
3
O
Ml
I-I
O
a
0
rt
rt
p-
O
3
13
-------
two is well within the reliability of the test methods. In subsequent
sections of this report, the data base used in the development of
charts, tables, and figures includes all 166 plants except as otherwise
indicated.
The control and treatment technologies employed at plants with
essentially no discharge ~of pollutants and at leaching plants were
identified during the on-site studies, and are discussed in Section
VIII.
The information, as outlined above, was then evaluated in order to
determine what levels of technology constituted the "best practicable
control technology currently available," and the "best available
demonstrated control technology, process, operating methods, or other
alternatives." In identifying such technologies, various factors were
considered. These included the feasibility of using technology employed
by other industries, the total cost of application of technology in
relation to the effluent reduction benefits to be achieved from such
application, the process employed, the engineering aspects of the
application of various types of control techniques, non-water quality
environmental impact (including energy requirements) and other factors
as discussed in sections IX, X, and XI.
Description of the Cement. Manufacturing Industry
The cement manufacturing industry is classified by the Department of
Commerce as SIC group 3241 (Hydraulic Cement). The products produced by
the industry are various types of portland cement, manufactured to meet
different requirements.
There are 51 companies with 166 plants currently in operation in the
United States and Puerto Rico. These plants are widely distributed, as
shown on the map in Figure 3, being located in all but nine states, in
areas close to sources of raw materials, transportation routes, and
local markets.
The number of plants in operation has declined from a high of 188 (12)
in 1967 to the estimated 166 plants at the end of 1972. In addition to
these, about five plants are presently shut down for modernization, and
five new plants are under construction. Expansion programs are also
underway or planned at about 20 existing plants.
The annual capacity of these plants ranges from 0.18 to 2.7 million
metric tons (0.2-3.0 million short tons). Table U shows the number of
plants in each of four size categories.
In 1971 the production of clinker by domestic plants was about 68
million kkg (75 million tons). (7) According to the U. 3, Department
14
-------
1
£ — .
Is
i*
L
CO
4J
C
4J
C
Q)
e
0)
u
c
•<-t
-M
(0
M
4-1
O
C
0
•H
-p
-H
M
-P
W
(d
O
D.
(0
O
0)
O
0)
l-l
3
-------
of Commerce (6), the value of cement shipments will grow from $1.6
billion in 1971 to $2.2 billion by 1975 and $3.1 billion by 1980.
Excess capacity has existed in the industry since a major expansion in
the early sixties. In 1971, the capacity utilization was about Q8%f and
is estimated at 90% for 1972—the highest in over 10 years. Expansion
programs currently underway should increase capacity about 2% in 1973.
(6)
Description of the Manufacturing Process
Cement is manufactured by a continuous process, normally interrupted
only to reline the kilns. There are 3 major steps in the production
process: grinding and blending of raw materials; clinker production;
and finish grinding. These steps are illustrated in Figure 4.
The ordinary ingredients for the production of cement include lime
(calcium oxide), silica, alumina, and iron. Lime which constitutes the
largest single ingredient, is most commonly obtained from limestone,
cement rock, oyster shell marl, or chalk, all of which are principally
calcium carbonate. Materials such as sand, clay, shale, iron ore and
blast furnace slag are added to obtain the proper proportions of the
other ingredients. At some plants it is necessary to beneficiate the
raw materials before they can be used. For example, if the most
economical supply of clay contains too much sand, the mixture can be
separated by washing with water.
Two types of processes are used in the manufacture of cement, "wet" and
"dry." At wet plants, the raw materials are ground with water and fed
to the kiln in a slurry. At dry plants the raw materials are dried
before grinding, and are ground and fed to the kiln in a dry state. The
moisture content of the raw materials available at a given location
16
-------
DRAFT
TABLE 4
DISTRIBUTION OF PORTLAND CEMENT PLANTS BY CAPACITY
Rated Annual
(thousands of
metric tons)
0-270
270-455
455-910
over 910
Capacity
(thousands of
short tons)
0-300
300-500
500-1000
over 1000
Number of
Plants
31
56
66
13
166
Percent
of Total
Plants
18.7
33.7
39.7
7.9
100.0
Percent of
Industry
Capacity3
7.4
24.0
47.6
21.0
100.0
a. Total rated annual capacity of industry is 86-million
metric tons (95-million short tons).
Data derived from RAPP applications, questionnaires, and
industry publications.
-17-
-------
Wet Process
.
\
Proportioning
and Mixing of
Raw Materials
in Slurry Tanks
"j
Grinding « — Vv
1
Homogenizing
and Blending
i
Ki
Evaporati
t
In
Raw Materials
I
I Crushing 1
I
~ Water
fater
on
/KilnX '
/ Dust \
*""Vsee Fig- /
V ure 5 ) /
*
1
Finish
Grinding and ^
Gypsum
Ad^i^iQn
1
Cement Cooler
I
Storage
Bagging
Shipping
Dry Process
1
Proportioning
and Mixing of
Raw Materials
1
Grinding
1
Homogenizing
and Blending
i
_^ Clinker
Storage
Figure 4. Flow Sheet for the Manufacture of
Portland Cement
18
-------
frequently determines which process a plant will use. For example, if
clay and marl with a high water content are available, the wet process
may prove more economical.
After the raw material has been finely ground it is placed in storage
containers—silos for dry process and slurry tanks for wet process. The
material is analyzed and the composition is adjusted as necessary to
obtain the correct formulation for the type of cement being produced.
The ground raw materials are fed to a kiln consisting of a large
rotating metal tube, usually 3.7 m(12 ft) or more in diameter and 75 to
150 m (250 to 500 ft) long, lined with refractory brick on the inside.
The kiln is inclined slightly so that the contents are transferred
forward as the kiln rotates. The raw materials are fed into the
elevated end, and the kiln'is heated by a flame at the lower end. An
array of heavy steel chains near the entrance is used sometimes and
serves to transfer heat from the gas stream to the raw materials.
The fuel for the kiln may be coal, gas or oil. Most cement plants are
equipped to burn more than one type of fuel, and the fuel used at any
particular time is dictated by availability and cost. When available,
natural gas is usually the least expensive fuel, but in order to obtain
gas at the most favorable price, the manufacturer must agree to curtail
its use when supplies are limited, and must, therefore, use coal or oil
as a standby fuel.
The amount of fuel used to manufacture cement varies with the efficiency
of the kiln, the composition of raw materials, the process used, and
many other operational factors. In 1963, on the average, the production
of one metric ton of cement required about 2U6 kg(541 Ib) of coal, or
187 cu m (6670 cu ft) of natural gas which is equivalent to
approximately 1.5 million kg cal. (5.8 million BTU). (29) Newer plants
would be expected to consume about 2Q% less fuel. Although the wet-
process kiln has a higher heat requirement than the dry-process kiln,
the fuel consumption difference, in many cases, is partially offset by
the heat consumed in those dry-process plants in which dryers precede
the raw materials grinding.
As the raw materials proceed down the kiln their temperature increases
to about 1600°C (2900°F). At this temperature the raw materials reach a
point of incipient fusion and hard, marble-sized balls, called clinker,
are formed As the clinker comes from the kiln it is rapidly cooled by
air (part of which is subsequently used as combustion air in the kiln).
The clinker along with a small amount of gypsum added to regulate the
setting time is ground into a fine powder. The grinding energy is
dissipated as heat in the product, and the cement is cooled before being
bagged or shipped in bulk to the user. One type of cement cooler
consists of a large, vertical cylinder with a rotating screw that pushes
19
-------
the cement through the cooler. The heat is removed by water, which
flows through an enclosed jacket around the cooler or cascades in the
open down the outside.
The finely ground cement is transported within the plant by pneumatic
pumps. The air is supplied by water cooled compressors. After the air
has been used to convey the cement it is cleaned with bag filters, and
the dust removed is returned to the product stream. In dry-process
plants much dust is associated with the grinding and pneumatic pumping
of raw material. This dust can also be collected in bag houses and
returned to the process.
Kiln-Dust^Considerations
Because of its impact on the environment, the collection arid disposition
of kiln-dust deserve special consideration.
The greatest source of dust at most cement plants is from the kiln. The
rotation of the kiln plus the rapid flow of gases (from the evolution of
carbon dioxide from the raw materials) and the motion of the chains
cause a large amount of the finely ground material to become airborne.
The high-velocity gases flowing through the kiln carry large quantities
of this dust (typically 10 to 20% of the kiln feed) out of the feed end
of the kiln. The large dust particles can be removed from the gases by
mechanical collectors (cyclones), but the smaller particles require more
expensive dust collectors (electrostatic precipitators, bag filters, or
wet scrubbers). Reuse of collected dust, if compatible with the
process, is advantageous from three points of view -- conservation of
raw materials, reduction of disposal costs, and reduction in
accumulation of solid wastes.
There are two ways to return collected dust to the kiln. In some plants
the dust is mixed with the raw feed. In other plants the clust is blown
in through a pipe in the hot end of the kiln, a technique known as
insufflation. A portion of the dust is often wasted to prevent buildup
of a large amount of fine particulate matter containing alkali salts
that continuously cycles between dust collector and kiln.
The dust that is removed from the kiln gases by the dust collectors is a
mixture of particles of raw material, clinker, and materials of
intermediate composition. The gases also contain alkalies from raw
materials and fuel that are volatilized in the hottest portion of the
kiln and condensed into a fume as the gases passed through the kiln.
The alkalies in the raw material are insoluble because they are tightly
bound in a mineralogical matrix. The high temperature in the kiln
alters the matrix sufficiently to free a large portion of the alkalies.
The free alkali is volatile at high temperatures, and it is also water
soluble.
20
-------
A.S.T.M. and Federal specifications require that the alkali content of
certain cement products not exceed 0.6%. The low-alkali specification
is only necessary in cases of known or suspected alkali reactions with
the aggregate being used, but many building and construction contractors
routinely specify low alkali cement regardless of the characteristics of
the aggregate. Therefore, since many manufacturers have difficulty
marketing high-alkali cement, they strive to make a low alkali cement as
a standard product. For plants that use raw materials with a high
alkali content, the
dust cannot be returned directly to the kiln, and its reuse and disposal
constitute a serious problem in the industry.
As air pollution control regulations have become more stringent, the
amount of high-alkali dust that is collected has increased, and as more
manufacturers install dust collectors that remove more than 99% of the
particulate load from the stack gases, the problem of disposal of high-
alkali dust will increase. Measures to minimize water pollution
stemming from increased amounts of high-alkali dust are described in
Section VII.
Figure 5 shows a schematic of the kiln-dust collection and handling
systems currently employed in the industry.
Table 5 summarizes the methods employed to dispose of kiln dust as
reported by 80 plants. As shown in the Table, only 27 (34?4) of these
plants are able to return all of the collected dust to the kiln.
Presently most manufacturers are wasting the collected kiln dust that
cannot be returned to the kiln. The dust is hauled or slurried either
to an unused part of the quarry or to vacant land near the plant. The
presence of the dust limits the future use of the dumping site.
Moreover, leaching of the dust piles by rainwater overflow from
slurrying can cause pollution of streams and ground water.
To avoid wasting high-alkali dust, some manufacturers have installed
kiln-dust leaching systems. The dry dust is mixed with water in a pug
mill to make a slurry containing about 10% solids. The soluble
alkalies, usually at least half of the alkali content, immediately
dissolve. The slurry flows into a clarifier where the solid material
falls to the bottom. The underflow from the clarifer which contains 40
to 60% solids is returned to the kiln. The overflow, which contains the
alkalies is discharged. This discharge constitutes the most severe
water pollution problem in the industry.
Another alternative is to use only raw materials of low alkali content.
Many cement manufacturers do not have a dust disposal problem because
their quarries centalr low-alkali raw materials. However, the alkali
content of the raw mateiials is only one of the many factors that must
21
-------
Kiln Dust
i
< ' 1 1
Electrostatic _ , _.
Precipitator Cyclone Bag House
1 1 I
Dust Bin
,
I , 1
Return Pile, Bury, Mixed with
to Kiln or Haul Water to *—
Form Slurry
Overflow Recycled
OC.4-+-1 -i n(-r _ Leaching
oet-UJ-J-ny (Overflow nasin
Pond * '
(Thickener)
1 4
Neutralization
i
>
Wet Scrubber
Make-
— up
Water
Underflow
» Returned
to Kiln
scharge
Discharge
Figure 5. Kiln Dust Collection and Handling
22
-------
DRAFT
TABLE 5
SUMMARY OF METHODS OF DUST UTILIZATION AND DISPOSAL
Number of % of 80 Plants3
Method Plants Reporting Reporting
All dust returned to kiln 27 34
Surface piling (dry) 29 36
Returned to quarry (dry) 11 14
Leached 9 - 11
Slurried and discarded 7 9
Some sold or hauled
away by contractor 8 10
a. Percentage total is greater than 100 because some
plants report more than one method.
Data derived from RAPP applications, questionnaires, and
plant visits.
23
-------
be considered in selecting a plant site, and many of the present cement
plants were constructed long before alkali problems became significant.
Cohrs (20) made a survey of 30 plants built since 1960 and found that
only ten had anticipated dust disposal problems prior to construction
and had made plans to handle it. In some cases plants have hauled in
low-alkali raw materials to avoid a dust disposal problem, but most
plants would find this solution economically prohibitive.
Since waste kiln dust has a high potassium content and considerable
capacity for neutralizing acids, suitable uses for the material have
been proposed. Some of the applications that have been, considered are
fertilization, soil stabilization, and neutralization of acidic wastes
from metal pickling operations and mine drainage. Although such uses
for waste dust have been pursued for many years, most of the dust now
being collected is discarded.
24
-------
SECTION IV
INDUSTRY CATEGORIZATION
Introduction
In developing effluent limitations guidelines and standards of
performance for new sources for a given industry, a judgment must be
made as to whether separate effluent limitations and standards are
appropriate for different segments (subcategories) within the industry.
The appropriateness of potential subcategories for the cement manu-
facturing industry was evaluated on the basis of inherent differences in
the characteristics and treatability of the effluent from plants
segmented with respect to the following features.
Method of Dust Collection and Disposition
Type of Process (Wet or Dry)
Plant Age
Plant Size
Raw Materials
Type of Fuel
Auxiliary Operations
Products Produced
Plant Location
As a result of an intensive study of the wastewater characteristics of
about 80% of the 166 plants in the industry, and an evaluation of the
technology available for control and treatment of these wastes, it is
concluded that the cement manufacturing industry should be divided into
two subcategories based upon the method employed for dust collection and
disposition.
Factors_Considered
Method of Dust Collection and Disposition
All cement plants collect large amounts of kiln dust and must either
reuse it or discard it. As discussed in Section III, if the alkali
content is too high for direct return to the kiln, the dust is either
leached or wasted.
25
-------
Whether wasted by means of wet slurrying to a pond or by dry piling,
contamination of surface waters can result from overflow of the pond or
runoff from rain. Adequate methods of controlling or eliminating
discharges from these sources are available.
In leaching operations, large volumes of water are generally involved
and the waste loadings are much higher than in nonleaching plants, as
shown in Figure 6. At the present time, no practical and completely
effective methods of treating this water for reuse are available.
Plants that use wet scrubbers for the collection of kiln dust employ
even larger quantities of water, which may become contaminated by
soluble materials.
Thus, based on the significant differences in waste loadings and
treatability of the wastewaters, two subcategories are defined:
~ leaching plants, in which the kiln dust comes into
direct contact with water in the leaching of kiln
dust for reuse or in the wet scrubbing of dust to
control stack emissions.
nonleachinq plants, in which contamination of water is
not inherently associated with the water usage.
Type of Process
As described in Section III of this report, there are two basic
processes for the manufacture of portland cement: the wet process in
which the raw materials are slurried with water before being fed to the
kiln and the dry process in which the raw materials are ground and fed
to the kiln without use of water. A review of the characteristics of
the wastewater and inspections of both types of processes, indicate that
the type of process need not have a direct effect on the quality of the
wastewater. Table 6 shows the average loading of several selected
parameters for wet- and dryprocess plants and the percentage of plants
of each type that report less than 0.005 kg per metric ton (0.01 Ib/ton)
of cement produced. The average loadings for wet-process plants are
slightly greater, due to the high loadings of the leaching plants.
26
-------
D
Alkalinity
Total
Dissolved
Solids
Total
Suspended
Solids
Sulfate
Potassium
Figure 6. Comparison of Loadings of Selected Parameters
for Leaching and Nonleaching Plants
Data derived from 88 RAPP applications.
27
-------
a" cu
3 3
o o
M M
C C
cu a.
a> re
03 CO
re re
co sa
o o
a* sr
P. H.
3 3
OQ OQ
W fil
3 3
*"d
o
rf
(U
co
CO
H-
g
§
cn
e
i — >
t-h
9)
rt
re
H
o
rt
fu
1 — i
C/s
c
CO
*o
(D
G.
re
a
CO
o
H-
(X
CO
H
O
rt
fu
a
CO
CO
O
H~*
re
ex
en
O
H-
a.
CO
>£>
I-1
PJ*
fu
H-
3
H-
rt
*-^
Ul
U)
Ul O
ho
Ul
Ul
o
CO
CO
O
u>
J>
^«^
o
*^J
**o
1,^
h- «
0* >
•-~
n 3
rt
SJ
re
rt
1
H
O
O
re
co
to
3
pD
3
rt
to
(u
H
I
o o o
O Os O
-P- M v£>
O O O H-" OS
O O O H" O
O Ml-'
00 hO VO
s— s \~s ^s
Ul Os ^J Co ^J
O "^-4 •£* N3 Ul
a- j>
rt (D
O H
3 P
s— ' CW
re
o •
*"* ?r
T3 OO
If
C 00
o
rt
C3 5^
• re
C^ *T^ *T)
O O fB
Ul H It
••-. rt n
39 H- ft>
--.33
7? 00 rt
W f1 O
re HI
T3 CD
K en H
0 O
C 31 f»
O £U H
rt 3
O
M
1
Hd
i-t
O
n
re
CO
CO
fu
3
rt
CO
cr
28
-------
almost all of which are wet, but the average is still relatively low.
Moreover, a significant number of plants in both groups report very low
loadings.
As discussed in Section VII, the two different processes offer basically
different options for water management and reuse. However, acceptable
options are available for both types of processes. Any difference that
may exist in the cost of implementing these options is likely to vary as
much among plants of the same type of process as among plants of
different types of process. Therefore, wet- and dry-process plants may
be included in either subcategory.
Plant Age
Portland cement plants range in age from 2 years to more than 75 years
since initial plant start-up. Analysis of the reported start-up dates
for plants representing 75% of the establishments in the industry
indicates that 16% of the plants are less than 10 years old while 37% of
the plants are less than 20 years old, and about 32% of the plants are
more than 50 years old. Analysis of the quantity of water used and the
wastewater constituents with respect to plant age shows no correlation
between plant age and either the volume of water used or the wastewater
characteristics. There are probably two basic reasons for this lack of
correlation: first, the basic process for the manufacture of portland
cement has changed little in the last 50 years; and second, cement
plants in general are constantly undergoing updating and modification.
Thus, a plant that was constructed in 1906 may be operating with kilns
and other equipment that are identical to those in a recently
constructed plant. Therefore, plants of different ages may be included
in either subcategory.
Plant Size
Analysis of the available data and inspection of plants of various sizes
indicate that there is no correlation between plant size and the quality
of wastewaters as shown in Table 7. The lowest and highest average
values for alkalinity and total solids are within one standard
deviation. Also shown in the table are the gross water discharged and
the water discharged per ton of product, which vary widely among the
large and small plants with no obvious relationship to plant size.
While a smaller plant may, through water conservation and good
management practices, consume and discharge far less water, this is not
necessarily the case. Differences in the amount of water discharged and
possibly requiring treatment may be reflected in higher costs of control
and treatment technology; however, since such differences are not
directly relatable to plant size, plants of all sizes may be included in
either subcategory.
Paw Materials
29
-------
o
CU
rt
(U
Cu
ro
It
H-
<
ro
Cu
Hi
<-(
0
S
CO
00
pd
£
>D
(B
X)
XI
[_-._!
P^
H-
0
to
rt
H-
0
3
05
fu
3
Cu
to
to
J3
fP
0)
rt
H-
O
3
3
cu
H-
H
rt
CO
o
rt
to
0
o
/~\
Ul ^J M
? ? ? H
to .P- to xi
O Ui ^-J M
O O O CO
9
y-^ >— s X-N rt
ui oj o to
0 O 1
?O OJ
T o
M Ul O
0 O
o o
o -^
*~s
(_J
Ul OJ 1— ' 1— '
OJ OO CO ^J
00 OJ to ^*J
• • • •
Ul OJ ^J to
y-N S*** X—N y~ N
to O O to
• • • •
to t£> *~l I-*
M to
00 00 -~l -vl
• • •
OJ 00 OJ
-P* to h~* ^*J
CO OJ t£3 S3
ON OJ -C" Ui
O 00 O I-1
-4 O >J O
to (_j )_i |_i
V V «* v»
O OJ •£"* *-!
to h-1 O ON
O O O O
4> tO f— ' to
u * ^* u
I— ' to ON to
1— i .£•« (jO ON
Ui J> 00 00
•P* OJ -P1* 4>
OO M O to
Ul 00 O 10
O O 0 0
I—1
O Ed
o to
O rt
ro
y$*
oo >
3
/-N 3
rt C
3* Cu
O M
co n
cu cu
Cu cu
n
rt H-
O rt
3 ^
to *
ja o
fO Hi
o *"d
H M
rt fu
H. 3
3 rt
n co
jt>
<^
ro
H
CU
W
ro
Q CO
ro rt
ro
tu
w
ro rt
< Cu
H- 3
Cu f^ .
rt Cu
O Cu
3
&
g
cr
ro
i-i
M
O
^.
Cu
CU
^
,^-x
3
05
X)
Cu
t^
P7*
^T4
BQ
^-^
TO
to
H- »
^~
O
3
O
"d
h^
O
Cu
c
rt
s:
rt
ro
G
H-
CO
O
3"
CD
W
CD
O
^j
•P-
Ul
o
/-N
W
0
1
Ul
o
o
f*
M
O I-1
1
to X)
O Cu
3
•^™S ft
?to
OJ
o
o
l_^
o w
O P
O rt
ro
;*r cu
?r
PQ g.
<-—\ P
*~9 C
3" Cu
O M
C
co n
CU Cu
3 XI
Cu Cu
O
i-t H-
O rt
3 •<
in *
G\
o
o
I" 4
•vj
o
•
to
tO
V — '
OJ
OJ
o
OJ
ON
1 — i
^^
O
•
**j
to
^_^
M
•
O
^
Ui
to
•
o
to
^^
to
ON
O
to
ON
OJ
^-^
0
•
Ln
LO
s«^
O
•
^O
OJ
o
M
•
OO
CT*!
^^
1 — '
O
0
NJ
4>
-C^
^~s
0
^
to
s^
o
OJ
to
to
o
^J
00
^— ^
> — J
Ul
0
to
00
OJ
,-x
o
•
Ul
^J
1 — '
0
00
-J
^o
UJ
•
^
ON
^^
ya o
fd Hi
T-H
W
o *"d
*"t h~*
rt fti
UJ« 3
3 rt
09 CO
O !f*
00^
B pr
H ?r*
O OQ
O-
n M
rt cr
*~^
rt
O
3
O F?
HiOQ
X3 7?
(-< ?T
O 09
C x^
n M
rt cr
\,
rt
O
3
2!
g
cr
ro
>
ro
H
Cu
OQ
ro
Cu CO
ro rt
< fu
H- 3
to Cu
rt Cu
O Cu
3
j£>
7?
Cu
H-
3
H-
rt
CP1
M
Ui
(^
00
W
•
I— J
-P*
x.^
00
•
CO
Ul
ON
,~v
^j
•
^
I-1
^rS
OJ 10
f> ON
t-1 1— '
Ul Ul
ON (-"
tO Ul
OJ OJ
• •
1- 0
*- OJ
°*~s ^^
OJ OJ
• •
ON -P-
ON to
10 Ul
/"~v y~s
-J ON
• •
OJ CO
10 Ul
Nw^ "^s
H-4 ^«J
O ON
M M
-P- -P-
Ul ><£)
ON t->
to to
• •
tO t£>
M CO
^^ ^^
to OJ
• •
O OJ
CO ON
ON OJ
S- S S- N
4> ON
» •
1 — ' ^J
*~4 OJ
^ — ' ^^
P3 O
ro H! a
XJ C
o TJ a
i-i M cr
rt Cu ro
H- 3 H
3 rt
09 a>
O I'T* J>
-^ ro
Td FT* ^
M ?^* Cu
O (J3 CTQ
M1* fD
n f--1
rt C71
""•^
rt
O
^
N""X
o ?;- cu co
HI cw ft) rt
^*»^. «^ fl3
•a T? H- 3
H JV cu CU
O 09 rt fu
Cu H- >-l
C ^ O Cu
0 (-• 3
rt CT'
* — ..
rt
O
3
H-3
O
rt
M
CO
O
) — '
H-
Cu
cn
o
Q
en
i
W
co O
W
o _
^Jl 2^
W O
M
^ I
n —
h-1 SO
% o
(—t
CO
O
w
o
§
H
W
PI
--J
-------
As discussed in Section III, the raw materials required for the
manufacture of portland cement are chemically similar, including the
oyster shell used at a small number of plants located along the Gulf
Coast. Analysis of the available data and on-site studies of exemplary
plants indicate that with the exception of alkali content, which will be
discussed below, only minor differences in the quantity or quality of
wastewater may be related to the type of raw materials used.
The raw materials that are available to some plants. especially
limestone and clay, may contain higher-than-average amounts of potassium
and sodium. These differences will be reflected in the wastewater
streams only at those plants where the kiln dust comes in contact with
the waste stream. Plants where such contact is purposeful rather than
incidental have already been considered as a separate subcategory.
Thus, the type of raw material is considered with respect to its
influence on dust handling techniques, and as such is covered in the two
selected subcategories.
Fuel
Few plants use only one type of fuel. The type of fuel burned may
affect the amount of water-soluble constituents in the kiln dust; and
minor differences may be found in the wastewater characteristics of
plants using different fuels, if the kiln-dust comes in contact with the
water. These differences are considered in the defined subcategories.
Leaching of coal piles by rainfall and subsequent runoff may be a
problem at some coal-burning plants, however, adequate methods for
controlling such runoff are available in other industries that have
large coal storage piles. Such methods include spraying the piles with
latex films that prevent moisture from entering the piles, and diking
the coal-pile combined with lime or limestone neutralization to prevent
discharge of acidic run-off water.
Ancillary Operations
A.S discussed in Section III, cement plants may conduct activities not
directly concerned with the manufacture of portland cement. These
activities include the generation of electric power from boilers heated
by waste kiln heat, the washing of bulk hauling trucks, the cleaning of
slurry tanks, the blowing-down of cooling towers, air compressors, and
boilers, and the beneficiation and washing of raw material.
Power generation by waste-heat boilers is limited to only a few plants.
While this operation could provide a basis for separate consideration,
pollutants in waters arising from this activity are intended to be
covered by effluent guideline document and regulations promulgated
separately at a future date by EPA.
31
-------
The other activities are practiced to some extent at most plants, and
the characteristics of wastewaters arising from such activities are
common to the industry as a whole which precludes consideration of
auxiliary operations as a basis for subcategorization.
Products Produced
Different types of portland cement are produced by either varying the
raw material mix and manufacturing conditions or blending additives with
the cement after the clinker has been ground. There are only minor
variations in the manufacturing process for making different products.
Several types of products may also be made at different times at the
same facility. With the exception of low-alkali cement produced from
high-alkali raw materials, the general waste characteristics will be the
same, irrespective of the type of cement being produced., Low-alkali
cement production affects water quality only at leaching plants and is
thus already considered.
Plant Location
Wastewater quality was not found to be related to geographical location.
Some variation may exist in regions of the country where the only
available raw materials are highly alkaline, but, this factor was
considered under raw materials. Thus, geographical location is not a
suitable basis for subcategorization.
The local topography as reflected by the availability of land or an
adjacent quarry that may be used for wastewater disposal varies
considerably from plant to plant. However, since other options,
discussed in Section VII, are available, topological considerations.
are not a reasonable basis for subcategorization.
32
-------
SECTION V
WATER USE AND WASTE CHARACTERIZATION
General
The operations where the largest volumes of water are used in cement
plants are essentially non-polluting. Process water in wet plants is
evaporated; most cooling water is not contaminated; the change usually
noted is an increase in temperature.
Any contaminated discharges contain constituents that are present in the
raw materials, collected kiln dust, or cement dust. These constituents,
which include aluminum, iron, calcium, magnesium, sodium, potassium,
sulfate, and chloride, may occur in any water that has contact with
these materials.
The presence of these constituents will be reflected as total dissolved
solids, total suspended solids, and high pH and alkalinity.
Other constituents, reported as BOD, COD, Kjeldahi nitrogen, total
volatile solids, and phenols, have been noted in the effluents of some
plants. However, these are related to the presence of organic materials
not directly related to the process of cement manufacture, but arising
from sanitary effluents, spills of fuel oil, runoff from coal piles, and
drainage from quarries, settling ponds and cooling ponds, which may
contain decayed vegetation.
Plants in the leaching subcategory have a higher pollutant loading than
other plants. This is illustrated by the average loading for six
selected parameters in Figure 6 and for 35 parameters reported in 88
RAPP applications in Table 8 for plants in both subcategories.
SpecificWater^Uses and Waste^characteristics
Water usage for the cement industry is summarized in Table 9 and in the
flow diagrams in Figure 7. These uses and the characteristics of the
associated discharges are discussed below.
Cooling Water
The major use of water at most cement plants is for cooling. This water
is used to cool bearings on the kiln
33
-------
N CO
H- 0
3 a.
O H-
^
^d a
0 H-
rt O
P 7?
co ro
CO M
H-
p
^
S 3
ro P
i-i 00
o 3
c ro
i-t CO
p
p
tr-1 M n n > >r|
ro f~t o p M i—1
Co O "T3 M C O
Cb 3 TJ O S C
ro M H- i-t
i-t g 3 H-
1 ro"
H
o
rt
P
EC
P
i-t
CX
3
ro
0)
en
H > 0
o o cr
rt H- it
P CL O
H H- S
rt H-
i-t 0
00
P
3
H-
n
O
P
i-t
cr
o
3
>-a co co co
cr c C c
ro M M M
3 Ml Mi Mi
0 H- H- P
t— ' rt {X rt
co ro ro ro
o o >"d
31 H- CT
M M O
O CO
H P X)
H- 3 U
pi . ("^ . Q
ro >~i
o c
I-t CO
ro
P
CO
ro
a ^ t>
H- '— >• B
rt ro B
i-t M O
P O. 3
rt p H-
ro 3* P
I— »
a
H- a
rt H-
i-t rt
o i-t
00 O
ro oo
3 ro
3
H rt
0 0
rt rt
P P
< CO
0 C
M CO
P 13
rt ro
LJ, ^
(—4 PJ
ro ro
a.
CO
O CO
h-1 O
H- M
CX H-
cn ex
CO
rt
o
rt
P
M
t)
H-
CD
CO
O
^
ro
ex
CO
o
M
H-
cx
CO
rt n w
o o o
r^ t? t^
pi «
i«_i
Ui
a»
O ^->
M P
H< ^
cx
CO
I>
) — '
pcj*
P
M
H-
3
(->•
rt
x«j
h-
1-1
OQ ?T* ^r1 OQ CTQ f*r* CJQ OP OQ
*• ^ \^'^^?7'^r^:'
oo
00 00
proooooo
00 00
?>'?r?r?r?^?r?r'?^?r?7'?r?r?r?^?r?^?x'?r'vs'?r?r
J^tc^^oooQ j^?r'?r'pr?^?r?r?7'?r??'?r?r?r?r?r
00000000 000000000000000000000000000000
o M
o cr
h-'OOH-'OOOI-'OMt-'Ml-'OOl
croocrooocrocrcrcrcrooi
rt
O
o
•
OJ
O M
s~<• /~**
o o
r-~i—•)—'I—'i—'i—'i—'I—'i—'I—' t—• f—' r^ r-1 '
crcrcrcrcrcrcrcrcrcrcrcrcrcrcr
rt rt rt
O MMO h-'l-'l-'O
3 o'er? cro-crs
O O
33
rt rt rt
O O O
333
O
3
rt rt rt i-trtrtrtrtrtrtrtrtrtrtrtrtrtrtrt
OOOMMO OOOOOOOOOOOOOOO
3330-0-3 333333333333333
O O
3 3
O O
o o
N)
O vo
xO I—' vo
00 I I *~ O
^O O^ l^J
ON OJ O
Ui 00 O ^J
O
O
co
I O O I
U)
O O
I I O
VD 1
O -O I I O O I
o ^ v\
OJ 00 OJ
VO NJ
W 00
U) *-
wo
OO
O
CO Mi
c o
cr H
o
rt ro
ro P
JO o
o cr
H H-
•
M co fad
co f
Tt M
> O
CO fO 00
S w
o
MI a
cr
ro
o o o o o o o
o o o
OOO
o OOOOOOOOOOMOOOOOOOOOOOOOOOOOOO p
OOUiMM^ONiUi •P^LO***'
CO •
c M MI
cr ro o
o P> 1-1
co n
rt
2 <
PQ 3 3
o OQ i
H
*-
»J Ul
cr
ro
"t
34
-------
D
(U
rt
(u
Cb
(D
t-f
H-
<
(D
D.
Hi
H
o
5!
(D
rt
en
0
H
d
tr
er
(D
n
o
d
CO
rt
0
H-
CO
t)
o
01
(U
H1
CJ
d
CO
rt
P
(D
f"
O
sr
H-
3
iQ
D
d
CO
rt
O
0
3
rt
H
O
M
TJ
H
0
O
(D
CO
CO
W
(D
3
CD
Mi
H-
O
H-
(U
rt
p-
O
3
s;
fu
CO
&•
H-
3
U5
d)
3
a
»
0)
s:
s
to
rt
CD
H
H-
P>
!-•
O
O
O
H
H-
3
iQ
a
CO
(D
oo
00
TJ
(U
13
00
H-
o
0>
rt
H-
O
3
CO
fu
3
KJ
VO
(D
CO
rt
H-
O
3
3
0)
H-
en
to
X~N QO
oo ,
o o
o o
to
o
K3,O
Ui MO
OO O--'
O
o
en
o
NJ ^
o cn
o o
i VO
00
Cn
(D
(D
s
te
O
0)
o >
w w
f
§ H
» vo
td
n
w
H
D
C
cn
Cn
•-• to
i§
^^ O
K
O TD rt TJ
3 H O (-<
"-' O 3 O
d
O
rt
H
rt
Oq /-N OQ
B3 o ew o O3
i—_< i , n\ i, i—i^^
J^ rn r_, r~n fTi
a,
PJ
\
cw
eft-
rt
OQ
rt ..rt
O TJO
3 l~{3
d
O
rt
(D
H O
H- Hi
0)
M JO
CW
P
O
Hi
O ^
3 H
^ O
O.
g
rt
c;
3
H-
rt
CO
33
-------
Intake
Water
100 1/kkg Raw. Mat.
Cooling
Cooling
Dust
Contact
Raw Material
Washing and
Beneficiation
2060 1/kkg Product
Mill Bearings
Kiln Bearings
Burner Pipes
Cement Cooler
Air
Compressors
340 1/kkg Product
Process
(wet plants only)
860 1/kkg Product
Dust Control
264,000 I/day
Collection
Clinker
Cooler
Kiln-Gas
Cooling
Slurry
Truck Washer
Road Spraying
Wet Scrubber
28,000
1/kkg Product
Leaching
1/kkg
Dust
Disposal
Clarifier
Recycle,
Reuse, or
Discharge
M
0)
•O
c
Overflow
1/kkg
Product
Settling
Discharge
Recycle or
Discharge
Figure 7. Diagram of Water Usage in Cement Manufacturing,
36
-------
TABLE 10
REPORTED COOLING WATER USAGE IN CEMENT PLANTS
Average Flow, Number of Range
Use 1/kkg (gal/ton) Product Plants Minimum Maximum
Bearing cooling 1,080 (284) 39 3.8 (1.0) 5,800 (1,530)
Cement Cooling 760 (200) 22 1.9 (0.5) 3,750 (985)
Clinker cooling 60 (23) 12 2.1 (0.6) 242 (64)
Kiln-gas cooling 322 (85) 4 92 (24) 770 (203)
Bucner-pipe cooling 265 (70) 2 258 (68) 272 (72)
Data derived from 39 questionnaires.
37
-------
and grinding equipment., air compressors, burner pipes and the finished
cement prior to storage or shipment. A summary of average volumes of
cooling water used for specific purposes is given in Table 10.
While cooling water is mostly non-contact, it can become contaminated to
some extent through poor water management practices. This contamination
may include oil and grease, suspended solids, and even some dissolved
solids. If cooling towers are used, blow down discharges may contain
residual algicides.
Process Water
For purposes of this discussion, process water is defined as the slurry
water used at wet plants to feed the raw material to the kiln. This
water is subsequently evaporated in the kiln and, therefore, does not
constitute a discharge.
The relatively constant volume of water used in the preparation of
slurry averages 860 1/kkg (260 gal/ton).
At a few plants, excess water containing a high concentration of
suspended solids is discharged from the slurry thickeners. This
practice constitues a non-essential discharge and is easily avoided by
recycling this water for making the slurry. Other losses of slurry may
occur due to poor maintenance of pumps, which become worn and develop
leaky seals. The resulting spillage may result in a waste discharge
with high solids if not controlled.
Kiln-Dust-Contact Water
There are three operations in which water contacts collected kiln dust.
The wastewater generated by plants with these operations constitutes the
highest loadings of pollutants within the industry.
The most significant of these operations is the leaching (removal) of
soluble alkalies from the collected dust so that the dust may be
returned to the kiln as recovered raw material. This operation occurs
at about nine plants. In all cases the overflow (leachate) from this
operation is discharged, sometimes without treatment. The wastewaters
from this operation are essentially identical for all plants, varying to
some extent in the concentration of individual constituents because of
differences in raw materials at each plant. These constituents include
high pH, alkalinity, suspended solids, dissolved solids, potassium, and
sulfate.
The second most common operation is the wet disposal of dust. In this
operation a slurry is also made of the collected kiln dust and fed to a
pond, where the solids settle out. The settled solids are not recovered
for return to the kiln, and the overflow (leachate) may be discharged.
The constituents of this discharge are essentially the same as those
38
-------
from the leaching operation. At least five plants use this wet method
to dispose of collected kiln dust and the volume of water used ranges
from 70,000 to 760,000 I/day (18,000 to 200,000 gal/day).
The use of wet scrubbers for air pollution control constitutes the third
example of water in direct contact with the kiln dust. At least three
plants in the industry use wet scrubbers to collect kiln dust from
effluent gases.
Other Water Uses
All cement plants have some accumulation of settled dust on the plant
property and this dust may show up in the wastewater in a number of
ways. Many plants spray water on the roads to prevent the dust from
becoming air-borne by truck traffic. Most plants also routinely wash
accumulated dust off the trucks. At some plants, certain parts of the
plant areas are also washed down to remove accumulated dust. The amount
of water used for these purposes varies widely, ranging from 950 to 9500
I/day (250 to 2500 gal/day) as reported in a sample of 12 plants. Some
of this water undoubtedly evaporates, but depending on the topography of
the plants, some of this water may drain into storm sewers or natural
waterways.
Water from surface runoff after rain may also be laden with the dust
that accumulates on the plant site. Runoff from dust piles, coal piles,
and raw material piles may also become contaminated. Plants with
boilers, cooling towers, and intake water-treatment facilities, have
blowdown and backwash discharges associated with these operations.
At some plants, raw materials are washed and at others the raw materials
are encriched by a beneficiation process; these processes may result in
wastewater discharges containing suspended solids.
Where an active or abandoned quarry is used as a receiving basin for
dust disposal or plant wastewater, the discharge from the quarry may be
contaminated with wastes associated with cement manufacturing. However,
where a quarry is used exclusively for the production of raw material,
discharge of any accumulated water (dewatering) if not considered in
this report and is intended to be considered in the Mineral Mining
Industry Effluent Guidelines Study. For nonleaching plants the average
net loading of suspended solids is less than zero, indicating that more
solids are removed from the intake water used in the plant than are
added by the process. However, 4 of the 58 plants of this group report
over 1 kg/kkg (2 Ib/ton) of product indicating a moderate level of
suspended solids is possible if not properly controlled.
For leaching plants the average discharge of suspended solids is 0.9
kg/kkg (1.8 Ib/ton) of product.
39
-------
SECTION VI
SELECTION OF POLLUTANT PARAMETERS
Definition^ of Pollutants
Section 502 of the Federal Water Pollution Control Act Amendments of
1972 defines pollution as "...the iran-induced alteration of the
chemical, physical, biological, and radiological integrity of the
water." The term pollutant is defined as "industrial, municipal, and
agricultural waste discharged into water."
For purposes of this report pollutants are defined as chemical,
physical, or biological constituents of discharged water that are added
in quantities measurable by routine analytical procedures greater than
0.005 kg/kkg (0.01 Ib/t) of product as a result of the water being used
in manufacturing operations characteristic of the industry. For a plant
with a discharge flow of 8.3 million liters per day (2.2 mgpd) and a
daily production of 1420 kkg/day (1560 t/day) average values for the
industry, a loading of 0.005 kg/kkg of product would correspond to a
concentration of less than 1 mg/1.
At some plants, other constituents may be added as a result of
operations that are not unique to the industry, but are considered
pollutants as defined in the Act. Pollutants from these sources may be
subject to limitations on an individual plant basis, or to limitations
developed for other point sources.
Pollutant^Parameters
Based on information on 35 parameters, listed in Table 8, as reported in
the RAPP Applications of 88 plants and analysis of wastewater at 10
plants, seven constituents have been identified as pollutants for the
cement industry. These constituents are present in the waste streams of
plants in both subcategories and are subject to the limitations
recommended in this report. Table 11 presents the relevant data on each
of these parameters, listed below, for plants in both subcategories.
41
-------
1. pH
2. Total dissolved solids
3. Total suspended solids
4. Alkalinity
5. Potassium
6. Sulfate
7. Temperature
Rationale for Selection of Specific Parameters as Pollutants
PH
Because of the water soluble alkalies in cement dust, any effluent
contaminated with dust will have an alkaline pH. Average pH values
range from 8.2 for nonleaching plants to 9.9 for plants in the leaching
subcategory. Figure 8 shows the distribution of maximum reported pH for
88 plants.
Total Dissolved Solids
Dissolved Solids are present in effluent waters that have contact with
dust. Average loading of dissolved solids is 0.27 kg/kkg (0.54 Ib/ton)
of product for nonleaching plants and 6.6 kg/kkg (13.2 Ib/ton) for
leaching plants.
Total Suspended Solids
Since cement dust is dense and tends to settle out rapidly, suspended
solids may be removed from the wastewaters before leaving the plant
property.
For nonleaching plants the average net loading of suspended solids is
zero. However, 4 of the 58 plants of this group report over 1 kg/kkg (2
Ib/ton) of product indicating a moderate level of suspended solids is
possible, if not properly controlled.
For leaching plants the average discharge of suspended solids is 0.9
kg/kkg (1.8 Ib/ton) of product.
Alkalinity
42
-------
W H1 I-1 I-1
cr
^
s
S.S?
,13 N.
ii-t rt
O CO
U> h-1 O
H- n
i§ °-
s 3
«, a
Id TJ
O Ul
5S
43
-------
c
•H
-P
QJ
CO
4J
4-1
O
C
U
II i i i n i
8 9 10 11
Reported Maximum pH
12
13
Figure 8. Distribution of Reported Maximum pH
44
-------
Because of their highly buffered nature, the effluents from cement
plants can have a relatively low pH and still have considerable
alkalinity. The average loading for nonleaching plants is 0.09 kg/kkg
(0.18 Ib/ton) of product.
For leaching plants the average loading is considerably higher, 1.38
kg/kkg (2.8 Ib/ton) of product.
Potassium
Where potassium is present in the raw material in appreciable
quantities, it will be the major soluble alkaline component of the kiln
dust collected in air pollution control equipment. Thus, potassium
salts will be found in water that has contact with the collected dust.
This is confirmed by the fact that leaching plants report an average
loading of 3.3 kg/kkg (6.6 Ib/ton) while other plants report 0.08 kg/kkg
(0.16 Ib/ton).
Sulfate
Sulfate is present in the raw materials and some additional quantities
may be formed in the kiln, at plants that burn sulfur-containing fuels.
Average net loadings of sulfate are zero for nonleaching plants and 6.7
kg/kkg (13.4 Ib/ton) for leaching plants.
Temperature
Since all cement plants use cooling water, a temperature increase is a
characteristic of the effluent of most cement plants. Because the
quantity of water used for cooling varies considerably, and is
distributed among a number of streams, the thermal pollution is
calculated in terms of actual heat generated (cal/kg of product or
BTO/ton) by dividing the increase in temperature by the daily production
and multiplying by the daily flow and an appropriate constant. In these
terms, the average thermal increase reported by 63 plants is 4800 kg
cal/kkg (17,200 BTU/ton) + 4150 kg cal/kkg (14,900 BTU/ton) of product.
These numbers may be back-calculated using the average daily flow and
production to give a typical temperature increase of 3°C (5.5°F).
Eleven plants report a t.ypical increase from 6 to 11°C (10 to 19°F) .
Figure 9 shows t.he calculated average temperature rise for 65 plants.
At some plants in the cement industry, thermal pollution must be
considered as a significant parameter.
Rationale for Rejection of Specific Parameters as Pollutants
The following constituents were considered, but were not selected as
pollutants for the reasons indicated:
45
-------
20
15
c
-H
4J
(-1
O
CO
-p
C
CM
O 10
(1)
U
t-l
Q)
D
n
n
n
34 5 6 7 8 9 10 11 12 13 14 15 16
Average Summer Temperature Rise, °C
17 18
Figure 9. Distribution of Calculated Average Temperature
Rise.
Data derived from 88 RAPP applications.
46
-------
BOD, Kjeldahl nitrogen, phenols, total organic carbon
These constituents are reported in the discharges for some cement
plants. However, their occurence is associated with nonmanufacturing
discharges, such as sanitary effluent and drainage from quarries or
ponds where organic material could be present. Since they are largely
identified with organic materials not associated with the manufacture of
cement, they are not considered pollutants characteristic of this
industry. The average loading of each of these constituents is less
than 0.005 kg/kkg (0.01 Ib/ton).
Calcium, magnesium, sodium, aluminum, iron
These constituents are present in both the raw materials and the
finished product; consequently they are sometimes found in the
wastewater generated by cement plants. sodium and calcium are more
prevalent in dust-contact streams. Since the presence of sodium and
calcium will be reflected in the level of alkalinity and total dissolved
solids, they will be indirectly measured and controlled by the
limitations on these parameters.
Aluminum and iron compounds are normally found only in dust-contact
streams and at relatively low loading levels and are included in
consideration of total suspended solids and total dissolved solids.
Heavy metals (lead, chromium, cadmium, mercury, nickel, copper)
With the exception of lead and chromium, significant loadings of heavy
metals have not been detected in the wastewaters for the industry. In
an apparently isolated case, lead is reportedly associated with the
discharge of a single plant that uses oyster shell. Chromium is only
present in the discharge of a few plants from non contact cooling water
systems.
Turbidity, total hardness, total solids, total volatile
solids, COD
These parameters are present in the wastewaters of the industry, but are
more accurately covered by inclusion with the parameters of suspended
solids, dissolved solids and alkalinity.
Oil & grease, ammonia, nitrate (as N) , phosphorus (as P) ,
sulfide, sulfite, fluoride, zinc
These constituents are not normally present in the wastewaters from
cement plants. Oil and grease can occur from leakage of bearings in
cooling-water streams. However, the average loading of this and the
other parameters in this group is less than 0.005 kg/kkg (0.01 Ib/ton)
of product for the industry.
47
-------
SECTION VII
CONTROL AND TREATMENT TECHNOLOGY
Introduction
There are relatively few operations in cement manufacturing where the
addition of pollutants to the water used is inherently associated with
the use of that water. For most of the plants in the industry,
pollution results from practices that allow materials to come in contact
with the water. Pollutant levels at these plants can be greatly reduced
or eliminated by suitable in-plant control measures that prevent wastes
from entering the water or by more extensive reuse and recycling* of
water that may become contaminated.
For the plants in the leaching subcategory, wastes are necessarily
introduced into the water and recycling is not feasible. Thus, for
these plants, treatment is required to reduce the pollutant loading.
Only a limited improvement can be expected from the application of
available control technology. The main control and treatment methods
for the cement industry involve recycle and reuse of wastewater. The
devices employed include cooling towers or ponds, settling ponds, con-
tainment ponds, and clarifiers. Cooling towers or ponds are used to
reduce the temperature of waters used to cool process equipment.
Settling ponds are used primarily to reduce the concentration of
suspended solids. Containment ponds are used to dispose ot waste kiln
dust. Clarifiers are mainly used to separate solids in dust-leaching
operations.
With the exception of plants in the dust-contact subcategory, both wet-
process and dry-process plants can achieve virtually complete reuse of
wastewater with existing state-of-the-art technology.
*In these discussions recycle means using again for the same purpose;
whereas, reuse means to recover for another use.
With respect to wastewater management, wet-process cement plants have
features that iistinguish them from dry-process cement plants. In all
wet-process plai~s, except for those that leach collected dust, the
wastewaters from sub-processes (e.g.plant clean-up, truck washing, and
cooling) and storm runoff waters, can be used in the raw mills to
prepare the slurry fed to the kiln. In the kiln the water is
evaporated, any inorganic matter in the water enters the product, and
any organic matter in the water is burned. Thus, for wet-process plants
complete reuse of wastewaters is possible, although in some existing
49
-------
plants installation of cooling towers or ponds may be necessary to
permit recycling of excess cooling water.
In contrast to the practices possible in wet-process plants, for dry-
process plants disposal of wastewaters from sub-processes in the kilns
is not possible. Nevertheless, a number of dry-process plants have
achieved virtually complete recycle of wastewaters by the employment of
cooling towers or ponds. The only discharge from these plants is the
small volume of "blow-down" or "bleed" water from cooling towers that is
required to prevent buildup of dissolved solids in the cooling water,
and where contaminated, these small volumes can be evaporated at low
cost.
Even without recycling, control measures can be taken to prevent
introduction of contaminants into the water effluent from the plant.
Cooling water streams can be segregated from other streams, and
precautions can be taken to avoid entry of dust into the cooling water
circuit.
In-Plant JTontrol^Measures
In-plant measures are primarily limited to the control of nondust-
contact streams. For plants within the leaching subcategory, control
technology consists of segregation of the leaching streams from other
plant discharge streams and conservation of water to minimize the volume
of water requiring treatment.
Control technology applicable to non-contact streams is discussed below
for the major water uses and potential sources of wastewater. The
individual plants referred to are discussed in detail at the end of this
section.
Cooling Water
In either wet-or dry process cement plants, water is used to cool
process equipment such as bearings, compressors, burner tubes, and
cement coolers by non-contact heat exchange. The wastewaters from these
cooling operations are hotter than the entering water. The temperature
rise in waters used to cool bearings is normally small, and desirably
low temperatures can often be achieved by a simple recycle system in
which heat is lost to the atmosphere from a small amount of pipe or a
package recycle system as is the practice at Plant A. In waters used to
cool compressors, burner tubes, or cement coolers, the temperature rise
is larger. However, if the temperature of cooling wastewater is
reduced, the waters may be recycled. Temperature reduction has been
accomplished in cooling towers (plants B and E) and in spray ponds
(plant F), or by simply recycling to a storage pond of sufficient area
so that surface evaporation maintains a stable temperature.
50
-------
The suspended solids concentration in recycled waters used in cement
coolers can increase because the cooling stream in many cement coolers
is open to a dust-laden atmosphere. If a cooling pond is used to cool
the water before recycling, the pond can also serve as a settling pond.
However, if cooling towers are used, a small-volume "bleed" or "blow-
down" stream from the recycle stream is normally provided to maintain
suspended and precipitable dissolved solids at a low concentration.
At a few plants, waste cooling waters from bearings or compressors may
contain lubricants. Such cooling waters can be segregated to prevent
dilution and treated to remove lubricants if necessary. Flotation and
skimming usually suffice for removal of lubricants, but emulsion
breaking may be needed in extreme cases.
Process Water
Process water as defined in this report refers only to the slurry water
used in wet plants. Since this water is evaporated, no direct discharge
is associated with it. However, precautions need to be taken to insure
that overflow from slurry tanks, leaks from slurry Ixnes, and tank
clean-up is prevented from entering the discharge from the plant or is
adequately treated before discharge. As discussed above, at many wet-
process plants the slurry mix itself can represent a convenient control
measure for handling at least some wastewater generated in the plant.
Unless these wastewaters are highly alkaline, they can be used to
prepare the slurry, as is done at plants A, B and C; the water is
evaporated in the kiln, and the wastes that would otherwise have to be
treated or eliminated by other control measures are consumed in the
product.
Runoff Water
For plants collecting a high-alkali dust not returnable to the process,
surface dumping on the plant site or in an adjacent quarry is most
common. Disposed of in this way, the dust could affect the quality of
the plant effluent through runoff or quarry dewatering. Therefore,
adequate precautions must be taken to enclose the dust disposal area
with dikes to contain runoff and to use areas of the quarry not subject
to flooding by ground water.
Another technique for disposal of dust is mixing its with water to make
a slurry that is pumped into a lagoon. In some cases the overflow from
the lagoon is discharged. However, in the past few years, at least
three plants that slurry their discarded dust have eliminated the
overflow from the lagoons by recycling this water for slurry disposal.
Plant H illustrates this practice.
Contaminants, primarily in the form of suspended solids, can enter
wastewaters in other ways; such as, in plant clean-up and truck washing,
51
-------
and by pick-up of dust by storm runoff waters. The amounts of solids
introduced into wastewaters by plant cleanup can be minimized by good
maintenance and operating procedures to minimize solid spillage and to
return dry dust to the process, and the solids introduced into otc-rn
runoff waters can be minimized by paving areas for vehicular traffic, by
providing good ground cover (e.g. grass) in other open areas, and by
removing accumulations of dust from roofs and buildings for return to
the process. Implementation of more stringent air pollution controls is
expected to result in a significant reduction in suspended solids in
runoff water.
If introduction of solids into wastewaters cannot be prevented, settling
ponds can be provided for the wastewaters that are affected by suspended
solids build-ups (e.g. the waters from floor-drainage sumps, waters from
raw-mill cleaning and slurry-pump leakage in wet-process plants, and
storm water runoff).
Treatment_TTechnQloqy
With the exception of settling ponds for the removal of
suspended solids, treatment of wastewater in the cement industry
is practiced primarily at leaching plants.
Leachate Water
As mentioned in Section VI, pH, alkalinity, suspended solids, and total
dissolved solids (principally potassium and sulfate) are pollutants
present in the effluent from leaching plants. The treatment technology
currently practiced can adequately control pH, alkalinity, and suspended
solids, but not dissolved solids.
Neutralization by the addition of mineral acids such as sulfuric acid
has the following effects: it lowers the pH to any desired level; it
eliminates alkalinity by neutralization of hydroxyl, carbonate, arvl
bicarbonate ions if it is followed by aeration to remove carbon dioxide;
oiicl it dissolves acid-soluble particulate matter such as lime that is
prei.tnt as suspended solids in the leachate overflow. However, it adds
tc the total dissolved solids content because the sulfate ions are
h'.'.i-*ier than any of the anions that are removed by neutralization,
Carbonation lowers the pH by replacing hydroxyl ions with catbonate
ions. Additional carbonation converts carbonate ions to bj Cdiboa-ate
ions. Total alkalinity is not reduced by carbonation,, because the
c.":bon dioxide escapes when the bicarbonate solution is acidified or
aerated. However, carbonation can Le used to reduce the hardness ot -;:hs
IfMChate, The solubility of calcium reaches a minimum value of ^6 ppm
(at 16°C1 when the pH has been lowered to 9,5 by carboriaticn, as r;nov,-r.
in Figure 10 (39) . Any subsequent addition of carbon dioxide t~ io^er
-------
c
o
•H tfl
-p d
(0 O
^•H
-P
C g
-------
the pH raises the solubility of calcium because calcium bicarbonate has
nearly the same solubility as calcium oxide.
The above discussion suggests that carbonation might be advantageous as
a treatment for leachate. Overflow from the primary clarifier could be
carbonated with stack gas to lower the pH to 9.0, near the pH required
for minimum solubility and an acceptable pH for discharge. This would
cause precipitation of calcium carbonate which could be removed in a
secondary clarifier or settling pond.
Carbonation may reduce the dissolved solids by converting dissolved
calcium oxide to less soluble calcium carbonate which appears as fine
suspended solids that must be removed by settling. Suspended solids may
be controlled to less than 50 mg/1 as is done in Plant I by proper
design and operation of the clarifiers.
The degree of clarification is determined by several factors including
the length of time the leachate remains in the clarifier, the turbulence
in the clarifier, and the characteristics of the dust. The residence
time and the degree of turbulence in the clarifier are fixed design
parameters. However, the characteristics of the dust can be controlled
to some extent.
One way of controlling the dust characteristics is by selecting what
dust is to be leached. Maximum flexibility of selection is achieved
when electrostatic precipitators are used to collect the dust from the
kiln exhaust gases. In electrostatic precipitators the larger particles
are more easily removed from the gas stream, so they are recovered in
the first stages of the precipitator. The smallest particles are
collected in the last stage. Precipitators are designed so that these
fractions of dust are segregated in several hoppers. The fine particles
in the last hopper have significantly higher alkali content than the
coarse particles in the first hopper. By leaching only the dust from
the last hopper, the load of the leaching system can be significantly
reduced. However, in Plant I all the collected dust is leached because
the coarse particles make the slurry easier to handle.
The settling characteristics of the dust can also be controlled by the
addition of flocculating agents to the water used for leaching the dust.
Although none of the leaching plants use a treatment process to remove
dissolved solids from the leachate effluent, there are methods and
technologies that are potentially applicable. Several processes that
might be employed include evaporation, precipitation, ion exchange,
reverse osmosis, electrodialysis, and combinations of these. Each
process must be considered in relation to the problem of disposal of the
removed salts. Some of these processes have technical limitations
associated with their use in this application. For example, in ion
exchange large amounts of acid and base are required to regenerate the
-------
resins. The amount of waste material would be approximately twice as
great as for other separation processes. Similarly, although reverse
osmosis is useful for desalination of dilute solutions, the dissolved
solids content of the leachate is too high for this process to be
practical.
Evaporation of the leachate could potentially eliminate the effluent.
Although solar evaporation would have low operating cost, it could be
used only in arid climates and where a large amount of land is available
for evaporation ponds. Evaporation by submerged combustion or heat
exchangers involves considerable cost for fuel and equipment. Waste
heat from the kiln might be employed for evaporation of leachate,
however, the economic feasibility of this practice is uncertain in the
absence of industry experience. Reduction of the quantity of water to
be evaporated by concentrating the leachate in some other process may be
desirable.
A technology that appears promising for concentration of leachate is
electrodialysis (ED), which has been successfully applied to the
concentration of sea water for the recovery of salt. (30) If ED were
used, the concentrated stream would be more easily evaporated and the
concentration of salts in the dilute stream would be low enough to allow
it to be recycled to the leaching system. ED could be transferred
directly to the concentration of leachate with two variations.
First, calcium ions must be removed to prevent precipitation and fouling
of membranes. Reducing the pH to 9.5 by carbonation with stack gas will
reduce the concentration of calcium ions to a minimum as was discussed
above.
second, reduction of the concentration of salts to a point where the
water could be recycled in the leaching process will raise the cell
resistance. Thus, more power must be provided than is needed for
recovery of salt from sea water. A third desirable feature is
additional carbonation to reduce the pH of the clarified leachate from
9.5 to about 8.0.
A flow diagram of a conceptual design for electrodialytic concentration
of leachate is shown in Figure 11. At a typical leaching plant, about
6.5 kg/kkg (13 Ib/ton) of dissolved solids are generated in the leachate
stream, of which potassium salts are a major component. If the typical
daily production of clinker is 1600 metric tons (1750 tons), the plant
will generate about 10 metric tons (11 tons) of salts per day or about
3300 metric tons (3650 tons) per year. The costs of operating such a
facility would amount to about $350/day.
A detailed description of electrodialytic concentration of electrolytes
is given by Nishiwaki in Chapter 6 in Reference 30. conventional
55
-------
w
o c:
rt n
H ro
o
P. H
p. j_.
PI •
ft ^
H- M
O O
«
O
O D
3 H-
O PI
0) iQ
3 n
ft p)
pi
rt W
H- 3*
O O
3 s:
H-
O 3
tr1 cn
(D rt
PI (D
O T3
3" CO
PI
rt H-
(D 3
H- fD 0
O 00
3 PI < Hi-
O (D 00
H- H- Hi fl> O 0
iQ 3 H
' |il O
C >Q O O iQ 0
H 3
m tr
::r pi
111 H1 M
pi HI rt \\
ui co h CD o« QJ
~— H- O PI Pi
M £3 |^ k^
13
PI
10 S H
M Hi pi rt
^-s d O rt H-
^1 H H fD PI
H- H H M 1
»O *< !•{ H1 rt G
d H-
o
pi
1-1
cr
o
3
PI
rt
O
H
M- P
3 fD
G.
J i
^
/
/
/
\
\
\
\
O
H
PI
n
H-
1-h
rn
H-
•O
W
II
H~J
U)
•
.C)
First
cn
iQ ft
CO O
T)
ffi
II
vp
•
cn
(D
o
O
3
PI
fD I-!
H <<
\
cn
Pi
3
o.
t-h
' n
H-
(— i
rt
fD
M
T3
a
n
00
0
O
P)
hj
cr
o
PI
rt
O
(-<
vo
Ul
cn
fD
o
o
3
a*
cn
iQ ft
^fcnH^MMBM» Ol Ol
w o
|V
56
-------
Partially
desalted <•
solution
. .
H20
H2O
V//////J
Concentrated
brine
t.
A
C
V.
A
i
C
V.
A
i
C
C - represents cation-exchange
membranes
A - represents anion-exchange
membranes Solution to be
treated
77777Z
Figure 11A. Diagram of Electrodialytic Concentration Stack
57
-------
electrodialytic equipment may be used. The only major change from the
practices used in electrodialysis for desalination is that the
concentrating compartments are not fed any water; the water that
overflows the concentrating compartments and is withdrawn as brine is
transferred through the membranes by electro-osmosis and osmosis.
A diagram of an electrodialytic stack for concentrating electrolytes is
shown in Figure 11A. The stack consists of many (up to 2000) cation-
and anion-exchange membranes arranged alternately to form solution
compartments, as indicated, between a cathode and an anode. The
solution to be concentrated is circulated through alternate
compartments, as shown. The other set cf compartments are closed at the
bottoms. No solution is fed to them but they are filled with solution.
When electrical current flows through the stack, cations and anions
transfer from the circulating solution through the ion-exchange
membranes into the closed compartments. Simultaneously, water transfers
from the circulating solution through the membranes as a result of
electro-osmosis and osmosis. The water, so transferred, overflows from
the tops of the closed compartments along with the transferred ions and
is withdrawn as concentrated brine. It should be re-emphasized that
although only a few membranes and solution compartments are shown in
Figure 11A, commercial stacks may have as many as 2000 membranes and
1000 solution compartments.
The usual mode of operation for electrodialytic concentration stacks is
known as feed-and-bleed operation. In this mode of operation only a
small portion of the circulating solution is "bled" from a recycle line
and returned to the cement process for reuse in slurrying dust. Most
(perhaps 80%) of the solution is mixed with a volume of fresh leachate
equal to the amount "bled" from the system and recycled to the "feed"
side of the electrodialysis stacks. With this "feed-and-bleed" mode of
58
-------
operation it is possible to transfer ions through the membranes at a
high rate, without decreasing the concentration of ions in the
circulating solution appreciably in any one passage through the stack.
It is desirable to maintain a relatively concentrated circulating
solution because with very dilute solutions the resistance of the stack
would be high. Therefore, the energy requirements, which depend on
resistance, would be high.
In the conceptual design, shown in Figure 11, leachate from the primary
clarifier would be carbonated with stack gas in two turbo-agitated tanks
arranged in series to reduce the pH to 9.5 so that CaCO3 will
precipitate. The liquid will be pumped to a secondary clarifier in
which CaCO3 can deposit on existing CaCOS particles carried within the
clarifier as inventory. The underflow from this clarifier would be
pumped back to the primary classifier; the overflow would be transferred
to two secondary carbonators of the same type as the primary ones.
In the secondary carbonators the pH is reduced to 8.0 to convert the
CaCO3 remaining in solution to Ca(HCO3)2. This step is expected to
prevent precipitation of calcium ions as the carbonate, since calcium
bicarbonate is more soluble than calcium carbonate. As an added
precaution against precipitation of calcium as either the bicarbonate or
the sulfate, univalent selective cation-exchange membranes should be
used. (Such uni-valent selective membranes are described and discussed
by Nishiwaki in Reference 30.)
No preatreatment of the feed other than that described above and
filtration is expected to be needed. Iron and manganese, which have
caused troubles with ED units for desalination, should not be present in
this feed because any iron or manganese present in the dust should be
fully oxidized, and should not leach from the dust at the high values of
pH in the leaching section. If silica leaches from the dust, it could
present a problem with silica slimes building up on the membranes. The
extent to which silica might be leached is not clearly evident.
The solution from the secondary carbonators would be pumped through sand
filters and into the ED stacks. As discussed previously, the ED stacks
would be operated by a feed-and-bleed method. The partially desalted
solution bled from the feed-andbleed system would be returned to the
primary clarifier for reuse in slurrying dust. The concentrated brine
that overflows from the closed compartments of the stacks would be sent
to an evaporation step. The evaporation could be performed in a solar
pond in arid climates, or by other means in non-arid climates. Since
only about 10,000 gal/day of concentrate must be evaporated, the cost
should be low.
Cost for a typical operation, based on this conceptual design, have been
estimated and are presented in Section VIII.
59
-------
The most valuable and most abundant cation in the leachate is potassium,
which if suitably recovered might be profitably marketed. The
agricultural grade of potassium sulfate has a market price of $77 per
metric ton of potassium oxide (38). Recovery of potassium from cement
dust was practiced during World War I to free the U.S. of a monopoly
exercised by the German Industry. One cement plant reportedly recovered
17.5 kg of potassium sulfate for each metric ton (35 Ib/ton) of cement
produced (15) .
In 1959 Patzias (21) made a study of a method for extraction of
potassium sulfate from cement dust. By leaching at high temperatures in
a pressurized vessel he achieved 84% recovery of alkalies from the dust.
After filtration the leachate was concentrated by evaporation,
neutralized with sulfuric acid, and evaporated to dryness. For a plant
treating 180 metric tons/day of dust containing 1.66% of potassium
sulfate the calculated capitalized payout for the process was 0.44
years, and the calculated net profit was $101,304. There would be no
discharge from this process because all of the water from the leachate
is evaporated. While a process based on this concept appears
technically sound, it apparently has not been exploited by the industry.
The economic feasibility re-evaluated in view of present costs indicates
a recovery cost of about twice the present market price. A flow sheet
illustrating this concept is shown in Figure 12.
Description of Plants _that^Dgnionstrate
Control and Treatment Technologies
About 30 identified plants in the industry are able to achieve
essentially no discharge of pollutants by application of the control and
treatment technologies discussed above. Eight of these plants are
discussed below to illustrate variations in particular methods used to
minimize discharge of pollutants. While no plants in the leaching sub-
category have achieved this level of performance, an example of a
leaching plant and a plant with a wet scrubber are included to
illustrate features of existing control and treatment technology which,
if implemented in proper combination, would result in minimum discharge
of pollutants. The information was obtained through on-site studies,
questionnaires, and telephone interviews.
Plant A - Complete reuse of all water, including runoff
This wet-process plant built in 1939 has electrostatic precipitators on
four kilns and bag houses on two kilns. All dust collected (about 10*
of the kiln feed) is returned to the kilns without treatment since the
raw materials used are low in alkali content. The overall water
management plan for Plant A is shown in the simplified diagram in Figure
13.
60
-------
S-l
0) O
.p O.
-P o
w o
3 CM'
Q
G
O
•H
•P
m
M
-p
X
CO
ro vn
n H
O M
to 0)
« H
(U
(0
U
t- 00
rH 04
Q)
C g
C
O
•H
4J
(0
M
4J
-»**•
c
o
•H U3
4J
rH CN
o
CO
01
• O>
O4 IT
o a
CO 4-
o
CO
0)
•p
1
C
o
•r(
•P
(0
o
D4
n)
w
O
•rl
(0
N J
-rl O
rH CO
(0 o
in n
4J
P
0)
O4 O
rH rH
O 0)
CO -P
4J
C
0)
U
O
MH
O
CM
)H
CU
O
O
Q)
C
o
-rl
-P
(0
N
-rl
(0
-P
CO
rl
U
CM
M
0)
-p
05
1
o
-p
.C 3
CO Q
rH rH
<0 •
CO
OJ
-p
-------
Quarry
Elevated ]
Pond I
Slurry Dredged from Pond
(intermittent)
00 1/kkg
Raw Materials
Raw Material
Beneficiation
Primary
Raw Mill
40,000 1/kkg
Raw Materials
Secondary
Raw Mill
3850 1/kkg Product
Evaporation
1
Kilns
Runoff
Truck Washej
House-
keeping
Make-up Water
from •
Municipal System
37 1/kkg Product
Bearing
Cooling
Cement
Cooler
Cooling
Tower
Settling
Pond
(sump)
i Slowdown
Figure 13. Diagram of Water-Management
Plan for Plant A
-------
The bearing-cooling water systems in this plant are closed recycle
systems. A small amount (less than 1%) of the recycling stream is bled
off and sent to the sump. An equal amount of fresh make-up water is
added. In the cement cooler the finished product is conveyed vertically
through a large cylinder by a screw mechanism. Heat is removed by water
flowing through a jacket on the outside of the large cylinder. The
temperature of the heated water is reduced in a cooling tower. Fresh
water is added to the recycling stream to replenish the evaporative
losses in the cooling tower. The tower blow-down (less than 1% of the
the recycle stream) goes to the sump.
The water needed for cooling-water make-up, raw-material beneficiation,
and slurry preparation comes from an elevated pond as shown in Figure
13. The pond is fed by water pumped from the quarry and by water
purchased from a municipal water system. Water flows from the pond to
the raw-materials beneficiation plant. Water accompanies the slurry
that is dredged from the pond and sent to a thickener. The overflow
from the thickener is pumped back to the pond, and the underflow is
pumped to one of two raw mills. Solids from the first raw mill are fed
to the second raw mill (along with some water). The slurry from the
second raw mill is kiln feed.
All waters from plant clean-up and truck washing drain into a sump.
Storm runoff waters are intercepted by a series of ditches and led to
the sump. The sump also receives blow-down water from the cooling
systems and drainage from a sand pile (the company sells construction
sand from raw-materials beneficiation). The sump is provided with a
level controller. Water is pumped back to the elevated pond on a
intermittent basis, controlled by a level controller. The pumps and
level controller are provided with alarm systems to notify plant
personnel in case of pump failure, because the sump could overflow into
an adjacent stream if the pumps failed during heavy rainfall.
Plant B - Complete recycle and reuse of water
This plant uses oyster shells as raw material. Wastewater treatment
facilities installed in 1973 consist of a system of settling ponds to
clarify wastewater from a clay-washing operation and to recover settled
solids for use in the process. Electrostatic precipitators are used to
collect kiln dust (about 6% of the kiln feed is collected as dust). No
dust is returned to the kilns. Some of the dust is used along with a
stabilized shell mixture for fill dirt on road projects in the area.
The rest of the dust is returned to an unused area of the clay pits.
In Plant B water is obtained from a deep well and is first used for
cooling, as shown in Figure 1U. The water for the cement cooler is
recycled through a cooling tower and water is added from the well to
replenish losses.
63
-------
(1150 1/kkg)
Bearing Cooling
Make-up Water
(80 1/kkg)
Cement Cooler
Evaporation (80 1/kkg)
Cooling Tower
Slurry
Preparation
(80 1/kkg)
(1030 1/kkg)
Belt Spray
(for shell)
Raw Materials
Beneficiation
Evaporation (1110 1/kkg)
L
Kilns
Evaporation (40 1/kkg)
Clinker
Cooler
Figure 14. Diagram of Water-Management
Plan for Plant B
64
-------
Some of the wastewater from the bearing-cooling circuits is used to
spray the belt used to transfer oyster shells from the unloading station
at the dock to the raw mills to prevent the shells from sticking to the
belt. This water is subsequently used for slurry preparation. Other
wastewater from the bearing cooling system is used for raw-material
beneficiation and subsequently used for slurry preparation. Still other
bearing cooling water is used to cool cement clinker by direct contact
and is evaporated. No wastewater is discharged from this plant.
Plant C - Complete reuse of water
This wet-process plant, built in the twenties is situated adjacent to a
creek. Two smaller creeks on the plant site are fed principally by
runoff, and originally drained into a larger creek. The flow from these
two creeks has been diverted to a sump to provide a source of water for
the plant. The larger creek is connected to the sump through a
spillway, as shown in Figure 15.
All process water for cooling, plant clean-up, slurry preparation, and
other uses is pumped from the sump to an elevated tank. In normal
operation the plant uses more water for slurry preparation than is
normally available from the two small creeks. Since the water used for
slurry preparation is evaporated in the kilns there is a net inflow of
water from the larger creek through the spillway into the sump. Thus,
no water is discharged from this plant, except during periods of heavy
rainfall, when the level of the water in the sump is higher than that of
the larger creek.
All cooling water is discharged through two outfalls into the two small
creeks. All waters used in plant clean-up and truck washing and water
that has seeped into the quarry, which is on the plant property, is also
discharged into one of the creeks.
All of the dust is collected by cyclones at this plant (about 6% of the
kiln feed is collected as dust) and is disposed of by surface piling
within the plant area. Any runoff of water from the dust piles drains
into the sump.
Plant D - Once-through cooling water isolated from contamination
As indicated in Figure 16, there are two sources of water for this
plant: a river, and a shallow well. River water is pumped through a
loop of pipe that traverses the area in which the mills and kilns are
located. About 1090 1/kkg (270 gal/ton) is withdrawn from the pipe loop
and used in the process. About 23,000 1/kkg (5500 gal/ton) is withdrawn
for use as cooling water for bearings and compressors. This cooling
water re-enters the pipe loop and is discharged to the river along with
some excess water in the loop that is not used, except for cooling the
wastewater from bearing cooling by dilution. About 230 1/kkg (55
65
-------
I
Creek 1
i
Creek 3
500
1/kkg
Bearing
Cooling
Sump
Holding
Tank
Dust Pile
Runoff
160
1/kkg
Cement
Cooler
10
1/kkg
House-
Keeping
Slurry
Evaporation 800 1/kkg
Kiln
Quarry
Creek 2
Figure 15. Water-Management Plan for Plant C,
66
-------
Intake
DRAFT
Raw
Mills
I
Cooling Water(208 1/kkg)
Process Water
I
River
Evaporation (1090 1/kkg)
f
Kilns
Cooling Water
I
Evaporation (230 1/kkg)
Clinker
Cooler
_i
Discharge
Finish
Mill
(375 1/kkg)
Well
Figure 16-
Diagram of Water-Management
Plan for Plant D
-.1
-------
gal/ton) is also withdrawn from the pipe loop to cool clinker. This
water evaporates. About 375 1/kkg (90 gal/ton) of water is pumped from
a shallow well to the cement cooler. The warm wastewater from the
cooling operation is discharged to the river. '»>-,.,«, -' «
Plant E - Recycling of all cooling water with cooling tower
This is a dry-process plant, built in the 1950's. The dust from- the
kilns is collected in bag houses. Almost all dust collected (about 5%
of the kiln feed is collected as dust) is returned to the kilns. Only a
small amount (0.015 metric tons per metric ton of product) is wasted by
returning it to the quarry.
With the exception of small amounts of water used for cleaning (e.g.
plant and truck clean-up) all water used is for non-contact cooling.
The wastewater from all cooling operations, typically 625 to 730 1/kkg
(150 to 175 gal/ton) of product, is recycled through two cooling towers.
The blow down from the towers (about 12 1/kkg of product) is discharged.
This amount of water could easily be evaporated at low cost. The water
required to replenish the blow-down and evaporative losses in the
cooling towers amounts to about 83 1/kkg (20 gal/ton) of product, which
is obtained from a deep well.
Plant F - Recycling of all cooling water with spray pond
This is a dry-process plant built before 1900. The latest modification
that affected water management practices was the installation in 1965 of
a reservoir with spray cooling and a recycling system for cooling water.
About 0.1 metric tons of dust per metric ton of product is collected in
a multicyclone collection system and is returned to the kiln.
Water requirements for bearing cooling and the cement cooler are about
2300 1/kkg (550 gal/ton) of product. All cooling water is recycled to
the spray-cooled reservoir. In the reservoir about 230 1/kkg (55
gal/ton) of product is evaporated. This plant also uses water to cool
cement clinker in a direct-contact process. This water, 83 1/kkg (20
gal/ton) of product, is evaporated. Water is supplied to the reservoir
at a rate of about 300 1/kkg (72 gal/ton) of product to replenish the
evaporative losses.
Plant G - Once through cooling water with settling pond
This is a dry-process plant about 35 years old. The plant withdraws
about 3000 1/kkg (730 gal/ton) of water from a river as shown in Figure
17. This water is treated by flocculation and settling and about 170
1/kkg (40 gal/ton) of backwash water from the water-treatment plant
drains to a settling pond. Approximately 2870 1/kkg (690 gal/ton) of
the treated water is used as cooling water. A portion of the cooling
water, about 375 1/kkg (92 gal/ton) of product is evaporated in cooling
kiln gases and cement clinker.
68
-------
(375
1/kkg)
(2495 1/kkg)
Intake-Water
Treatment
Evaporation
Kiln Gas
Cooling
Evaporation
Clinker
Cooling
Bearing
Cooling
Cement
Cooler
(3040
.1/kkg)
Backwash
(170 1/kkg)
Settling
Pond
I
River
I
Figure 17.
Diagram of Water-Management
Plan for Plant G
69
-------
Dust from
Precipitator
l
Precipitator
Hopper
Agitated
Tank
Stack
gas
Carbonator
Make-up Water
(1190 1/kkg Dust)
Inactive Lagoon
(being excavated)
Active Lagoon
Figure 18. Diagram of Dust-Handling
System at Plant H
-------
All other water drains into a settling pond. Water overflows a spillway
at the low end of the settling pond into a small creek that leads back
to the river.
Plant H - Recycling of waste-dust-slurry water with stack gas
neutralization
This is a wet-process plant about 10 years old. Dust from the kiln is
collected in an electrostatic precipitator.
In 1964 a dust-leaching system was installed in the hope that the dust
could be returned to the kiln. However, the system could not be made to
work acceptably. some of the components of the system were then used to
develop a system for disposal of the dust. This system appears to be
adaptable for use at other plants and is, therefore, described below.
As shown in Figure 18, dust from the precipitator hopper is transferred
to an agitated tank, where it is mixed with water. A slurry is pumped
from this tank through four gas absorbers in series. A small amount of
the gas from the stack is sparged through the slurry in the gas
absorbers to reduce the pH from about 12 to about 8 by absorption of
carbon dioxide. The slurry is pumped from the last gas absorber to a
system of two lagoons. The distance to the lagoons is about 460 meters
(1500 feet), and much of the distance is traversed by fire hose. The
fire hose is used because precipitates tend to deposit inside the hose,
and periodically the hose is collapsed by walking or beating on the
outside of it to break-up and flush out the deposits.
Both the dust and precipitates formed by carbonation with kiln gas
settle in one of the lagoons. The water drains into a sump in the
lagoon that is provided with a floating suction-head
and a pump. The clear water is pumped back to the dust-treatment tank
for reuse in slurrying more dust, some water is lost from the lagoon.
Since the lagoon was made with an impermeable clay bottom, presumably
most of the water is lost by evaporation. The make-up water supplied to
replenish losses averages about 1300 1/kkg (315 gal/ton) of dust, or
about 83 1/kkg (20 gal/ton)
Each of the two lagoons is about 2.43 ha (6 acres) in area. Two lagoons
are provided so that one could be used to receive slurry, while the
other was excavated for sub-base fill for use in road and parking lot
construction. The plant sells the sub-base fill to a construction
company. By the time one lagoon is filled with solids, the second has
been excavated so it can be used to receive slurry.
Plant I - Sedimentation for removal of suspended solids from leachate
stream
71
-------
This plant uses cyclones followed by electrostatic precipitators to
collect kiln dust. If all of the collected dust were returned directly
to the kilns, the alkali content of the product would be 0.8 to 0.9%,
well above the 0.6% maximum for low-alkali cement. By leaching the
alkalies from the dust before it is returned to the kiln, the alkali
content of the product can be maintained in the 0.5 to 0.7X range. It
is the practice at this plant to leach all of the collected dust and
return it to the kiln.
The plant has two kilns and two separate dust collection and leaching
systems. Dust collected in the cyclones and precipitators of each kiln
is conveyed to a pug mill where well water is mixed with the dust to
make a slurry containing 10% solids. The soluble alkalies, usually
about one third to one half the alkali content, dissolve quickly. The
slurry enters the center of the clarifier and is distributed by a
revolving bar. The leached dust particles settle to the bottom of the
clarifier to form a dense slurry. The rate of removal of material from
the bottom of the clarifier is controlled to maintain a solids content
of about 45% in the underflow. The underflow is pumped back to the
kiln.
The combined overflow from the two clarifiers flows directly to the
river. It has a pH of 12.9 and is only slightly turbid (suspended
solids content of 40 mg/1). This low value of suspended solids content
suggests that the 13.7 m (45 ft) diameter of these clarifiers provides a
rise-rate that is adequate. (A similar plant with 8.5 m (28 ft) diameter
clarifiers had 660 mg/1 suspended solids in the overlow.)
Plant J - Treatment of wet-scrubber effluent
This plant uses a wet scrubber as its main dust collector for the
combined exhaust from three kilns. The effluent from the scrubber is
treated with a polyelectrolyte before it flows into a clarifier where
the major portion of particulate matter is removed and returned to the
raw mills. The retention time in the clarifier is 3.7 hours. Sulfite
and sulfate that are adsorbed from -the stack gases by water are
apparently converted to hydrogen sulfide in the clarifier (perhaps by
sulfur bacteria), since there is a strong odor of hydrogen sulfide at
the clarifier if chlorination is not practiced. Chlorine is added to
the leaving the clarifier to oxidize the sulfide ions. Then the water
cascades down the side of the quarry into a large pond. After the
particulate matter settles the water is recycled from the quarry through
the scrubber.
The decision to install the wet scrubber described above was based on
the significantly lower cost of a scrubber compared with that of a
haghouse or an electrostatic precipitator. This cost advantage was
reduced somewhat by subsequent modifications to meet wa-cer pollution
control standards. Although plagued with many operational problems
initially, the scrubber is now operating satisfactorily.
72
-------
SECTION VIII
COST, ENERGY, AND NO&-WATES QUALITY ASPECTS
Cost and_ Reduction Benefits^ of ^Alternative Control and
Treatment Technologies
A detailed analysis of the costs and pollution reduction benefits of
alternative control and treatment technologies applicable to both
subcategories of this industry is given in this section of the report.
Table 12 summarizes the results of the analysis.
Nonleaching Plants
The present waste loadings from a typical nonleaching plant are shown in
Table 12. These values represent the median of all values greater than
0.005 kg/kkg (0.01 Ib/ton) of product reported by nonleaching plants.
Alternative A - Recycling and reuse of all water used in manufacturing,
and containment or treatment of runoff from kiln-dust piles
This alternative will result in essentially no discharge of pollutants.
The investment cost of implementing this technology at a typical plant
will be about $200,000 including a cooling tower ($94,000) or spray pond
($91,000), the necessary piping ($76,000), and containment dikes for
coal piles and kiln-dust piles ($35,000). If an evaporative cooling
pond is used, it would cost about $160,000 including piping, but not
including land cost.
The operating costs of Alternative A will range from about $20,000 to
$30,000 per year including maintainence, sludge removal, chemicals,
labor, cost of power, and taxes and insurance. Power costs are limited
to pumping and amount to $13,000 per year.
Alternative B - Limited reuse and in-plant controls
This alternative consists of isolation of cooling streams from possible
contamination, reuse of cooling water in feed slurry (wet-process
plants), retention and reuse or treatment of miscellaneous wastewater
(§•9i truck washing) and containment or treatment of runoff from coal
piles and kiln-dust piles and would also result in essentially
73
-------
H 2
3- pi
fD X
H H-
3 3
pi c
!—• 3
C> fr^
1-3
»-*
H-
3
0
0
*a cn o
O C H-
rt H co
PI Hi CO
CO PI O
oi rt M
H- fD <
§fD
DJ
cn
o
(-<
H-
DJ
CO
cn >
C M
01 X"
13 PI
(D M
3 H-
DJ 3
fD H-
DJ rt
•<
cn
O
(-•
H-
DJ
01
'fD H- M
X 3 *i
O ^
(0 ?!* t"1
-a IQ G
rt\ M
*• Z
rt *• i-3
3-iQ
(D O
HOG
3 H>>
pi f*
I-1 O H
§1-3
^
3 fD
DJ 3
rt
•a
K
1-3 M
0 3
rt n>
pi HI
I—" iQ
^
P>
3
*d
O
fD
k?f
H- H
3 PI
rt rt
(D H-
3 O
PI 3
O pi
fD 3
P,
O O
fD ft
tJ T!
H H-
(D rt
O Pi
H- I-1
PI
rt
H-
0
3
Z
3
1
O
0
cn
i~3
cn
M
1^
w
cn
3
W
Z
•-3
' £
^3
W
Z
i-3
H
<
w
w "
cn
n
H
t-3
H
O
$
H
W
ft*
t-3
H
<;
W
o
n
w
w
ISJ
o o o o o
1 • * • • •
O O \-> O H1
00 ** VO ~J 1O
Ul Ul
n Z cn t
O O ft H
3 PI (D
rt > rt co
H DJ fD fD
O DJ 3
M (D rt
01 DJ
G
W
Z
M
to
O D
M H-
!-• O CO Z
C Hi O O
rt 3"
& &>
J3 ^
rt u3
CO (D
O D
I-1 H-
(-1 0)
C O
rt O 31 Z
PI Hi pi O
3 H
rt iQ
w fD
-co
-~j
vo
vo
o
o
•£/>
H- Ul
U) O
o o
o o
o o
M I-"
o o\
Ul *».
o o
o o
CTl
VD
o
o
-CA
•CO KJ
Ul O
M M
o cn
O O Ul tt^
o o o o
o o o o
o
o
cn
-co
N)
O
<_n
•w
o
CD
O
•{/>
to
O
Ul
•»
o
0
o
D Pi
C 3
cn DJ
rt
n
h3 O
H-3
M rt
fD PI
H-
fj 3
3 fD
O 3
HI rt
HI
O
Hi
H
O
?|
m
o
H
cn
'a
h^
PJ
t)
o
3
DJ
cn
rt
(~^
m
PJ
3
01
-.
i — >
H-
3
H-
rt
fD
a
H
fD
C
01
fD
M
3
rt
PI
M
t-1
P>
rt
H- |>
3
O
Hi
O
o
o
M
H-
3
M
0)
O
I-1
Z
0
z
1
f
w
>
n
K
H
Z
O
*XJ
5
z
cn
PI
ft
p-
o
3
0 |W
HI
O
o
o
H-
3
LQ
&•*
Z
D
*T?
0
f
c
M
O
z
HJ
w
o
G
n
^
H
O
Z
w
w
z
w
H
»-3
cn
W
ro
74
-------
8>
•
to
p)
cn
I
O
3
tCt
C
pi
3
rt
P-
ft
*<
rt 3C *C
tr p o
rt) X rt
H |-»* ftf
g g to
PI C cn
t> BB
^^
P-
3
o
n
CO O CO >
C H- C I-1
P* cn cn :*•
Hi M tJ p
01 O (D I-1
rt p- 3 P-
n> < & 3
(D CD P-
Qi DJ rt
•<
CO CO
o o
p" 1-1
P- P-
a. CL
cn cn
ro p- B
x 3 "a
o B
ro X1 tr1
T3 vO G
rt\ B
?r Z
rt *• h3
(1) O
HOG
(u t"1
H* O H
§1^
t^
t3 CD
Qi 3
rt
*o
»
t-3
O
rt
PI
H
^
2J
Z
W O D n G
3 IS *O (D pi (f
(D PI (6 'O 13 r
H P- H h P-
iQ 3 PI (D ft n
*< ft ft O PI O
fl> P- P- H- CO
Pi 3 O P H
3 PI 3 ft CO
& 3 P-
O PI O
*d (D 3 3
o a
J|
(D
H
> o
h B
1-3 CO
B n
50 50
•> 13
H H
H H
< O
B Z
P>
O
y
a>
o.
cn
rt
i <
(-•
U>
to o oo
ui
n z co >«
O O rt it
3 P (D
ft p rt cn
it QJ (D (D
O Q, 3
M rt> rt
ca O.
L?
VO OJ CJ CTv O H"
* o\ H to
tn to ui oo
M -C/l-CA
10 M *>•
VD OJ O
Ul O O
O O O
O O O
-C/»-l/»
£t to
to *•
Ul O
0 O
o o
•CA
i£fc
to
Ul
o
0
o
Settling
o
HI
fH
(D
pi
O
3-
P
rt
fl>
P
rt
(D
H
(D
C
ft
h(
Pi
1— '
P-
N
P
rt
p-
O
3
Pi
3
a
Cooling a
3
a
3
p-
ca
O
(D
P1
P»
PI
3
O
C
ca
50
fl>
0
•<
O
(D
Pi
3
d
» |O
ID
(^
n
n
o
H>
f
B
O
S3
Z
O
3
rt
H-
3
C
(D
o o
M P-
M cn
C O O Z
ft Hi 3" O
p PI
ft iQ
cn (D
to
to
o
o
-w-c/>
P* oo
o o
o o
o o
ui o
o o
o o
-------
3- pi O
fD X rt
H. p- pi
3 3 tn
pi c: 01
-.'O
p> J33
P-
3
o
n
co D
c P-
I-1 01
Ml 01
D) O
rt
en
&'
O
p-
01
P4
p-
rt
CO
o
M
p-
a
CO
fD
X
o
fD
W
t-1
a
w
z
i-3
o
a
1- O H
{u
3
a.
t3
w
D W
C 3
01 fD
ri~ M
n>
D O
fD 0>
T3 ^3
i-( P-
P-
3 0i fD rt
OKI rt rt O (a
fD
01 p) 3
P- p-
O pi
3 rt
'O 3 (H
O & 3 P-
01 O P> O
0) t) fD 3 3
H- O CX
fD
H
Z
G
O
O
en
CO
M
CO
> D
t^ W
H to
W O
Z H
H H
< O
W Z
t-1
W
W
tn
lr<
W
u>
O D
I-1 H-
I- Ul
cons:
rt M> 3" O
PI pi
3 n
uq
tfi
ft)
*.
vo
o
o
M
U1 CJ O
O CT1
000
o o o
o o o
Ln 4^.
o o
o o
to
o
Ul
o
o
o
D >
d cr
01 Pi
rt 3
f O
fD 3
& 3
O fD
3" 3
P- rt
n
o
3
rt
H-
3
C
(D
f
W
n
K
|!W
cn
76
-------
no discharge of pollutants in manufacturing effluents.
Cost of implementing this alternative at individual plants may vary
widely but on the average will be comparable to that for Alternative A.
About 35 of 154 plants in the nonleaching subcategory (23%) are now
achieving essentially no discharge of pollutants under either one of the
alternatives described above.
Leaching Plants
The present waste loading from a typical leaching plant is shown in
Table 12. These typical loadings are substantially higher than those
from the typical nonleaching plant and reflect the added presence of the
leachate stream.
Alternative C - Segregation and Treatment of Leachate Stream
The nonleaching streams of leaching plants are treated like those of
nonleaching plants under this alternative. Treatment of the leachate
stream consists of neutralization of the leachate with stack gases to pH
9.0 followed by secondary sedimentation to remove both the residual
suspended solids that were present in the leachate and the suspended
solids (calcium carbonate) created by the neutralization with carbon
dioxide.
This alternative will result in an acceptable pH of less than 9.0, and a
suspended solids level of not more than 0.15 kg/kkg (0.30 Ib/ton) of
dust leached. Dissolved solids will remain at about their present
level.
The cost of implementing Alternative C will be about $425,000 including
$165,000 for the control of nonleaching streams and the cost of
installing a stack-gas neutralization system and a clarifier ($260,000).
Operating costs of Alternative C will range from about $35,000 to
$45,000 per year.
One of the 12 plants in the leaching subcategory is presently equipped
to implement this alternative with minor adjustments in operative
procedures, this plant could meet the limitations of this alternative.
Alternative D - Recycling of Leachate Water
This alternative consists of reducing the dissolved solids in the
leachate stream by means of electrodialysis and recycling the partially
demineralized leachate. The technology of alternative C must be
implemented to provide a stream acceptable for electrodialysis. The
concentrated brine resulting form this treatment may be evaporated for
the recovery of potassium salts or contained in a suitable pond.
77
-------
t-,
D
s:
en fD T3
:r n M
rt H O
000
3 3 cn
Dep
D
xes
Ins
Operati
Repair
r1 i-
M- OQ
3 sr
to Ln HI |
to ro
Ln CO
O O
O O
O O ro ro
UJ LO O to
0 0
ON CO
CT> CO I—1 I
00 Ln Ln •
O O
O O
ON -J
LO \Q
LO -0
I—* I—1
CO vO
O 0
O O
Ln O^
0 O
to ro
(-• LO
to ro
£ £
t— > l—1
Ln — 1
Ln O
to to -j -
LO ON to C
vO LO LO 4
^D M (-• M-*
Jsj tO Ln -~i
O 0
O 0
Ln Q"I
h- ' h-1
Ln -J
^D Ln
h- ' tO
to t— '
M ro
oo o
ro to
io £
Ul ON
•-J LO
Ln ro
O p
o o
Ln -J
oo LO
O \Q
O O O
Ui CF1 O
O O O H* h->
o i~j i— ' ro 4^-
cjs M ro vj o
I-"1 h-1 LO
i-* ro j>
LO
CO
CO
4>-
O
VD
ro
o o
o o
O O LO LO ON --J
Ln LO O *- O VO
b o
o o
ON OO
p O
•P- O
p o
•-J I-1
LO LO
O LO
O O
o o
O Ln
Ln ^O
ON 00
00 Ln
O LO
LO .p-
M ro
oo o
O 0
Ln O>
3o
O O
LO LO
ro Ln
"o o
S SN
to *-
ro LO
1^3 ro
to ro
LO -P-
o o
•-J OO
Ln LO
O ro
CO CO
ro ro
ON tO
Ln '-'
Ln O>
vO Ln
ON Ln
p o
o o
p p
Ln L/»
O O
o o
-------
Implementation of Alternative D will result in essentially no discharge
of pollutants. None of the plants in the leaching subcategory, however,
is employing the technology described as Alternative D.
Alternative E - Abandonment of Existing Leaching Operations'
Under this alternative, plants that presently leach kiln dust would
abandon the practice and adopt either alternative A or B which will
result in no discharge of pollutants. A contractor would haul the dust
for about $0.50 per ton. The value of the wasted dust would be about
$2.00 per ton. (46) Therefore, the annual cost of wasting 200 tons per
day of dust that is presently leached would be $165,000.
Effects_gf^Costs on the
The investment cost of $200.000 involved in implementing control and
treatment technology at an existing nonleaching plant represents 0.5 to
1% of the estimated replacement cost of the plant ($20 to $40 million).
In terms of plant size, these costs represent about $0.35 per metric ton
of capacity. For plants in the leaching category, these figures may be
approximately doubled.
The increased cost of manufacturing cement will range from about $0.10
per metric ton at nonleaching plants to about $0.21 at leaching plants.
One industry consultant has provided the typical production cost figures
for 14 plants presented in Table 13 (5). The production cost ranges
from $15.11 to $21.20 with an average of $17.52 per metric ton. The
added cost of water pollution control will thus increase production cost
by less than 1.5% at plants operating at full capacity. Since these
costs are largely fixed costs and, thus, must be borne at any level of
production, production at less than full capacity will reflect higher.
added costs.
Energy Requirements
Because of the large energy requirement at a cement plant, about 1.25
million kg cal (5 million BTU) in fuel and about 120 kwhr of electric
power per metric ton, the added power needed to operate the recycling
systems is neglible (less than 0.1%).
Non-Water Quality Aspects
Non-water quality environmental effects of the alternative control and
treatment technologies described appear minor.
Some additional solid wastes will be generated by increased use of
sedimentation, but the amount will be small compared to the quantity of
79
-------
kiln dust normally wasted. Moreover, the relatively inert wastes are
acceptable for land fill.
The increased cost of dust leaching may discourage its practice at r ome
plants and thereby add to the solid waste load and create localized dust
problems on windy days.
Plant
The typical plant used as the model for this discussion is a
hypothetical wet-process leaching plant with a rated annual capacity of
520,000 kkg (580,000 tons). It operates continuously for 330 days per
year and produces 1,580 kkg {1,750 tons) of clinker per day. The water
flow for all cooling except finished cement is 2,360 1/min (600
gal/min) ; flow in the cement cooler is 1,130 1/min (300 gal/min) ,
About 130 kkg (150 tons) of dust are collected each day and leached for
return to the kiln; flow of the leachate stream is 510 1/min (140
gal/min) .
The plant site is about 240 m x 400 m (800 x 1,200 ft) not including the
quarry. Layout of the plant is shown in Figure 1.
This typical plant varies from actual plants in the industry as shown in
Table 3. The typical plant represents an average of actual plants
studied. Variation in the costs involved in implementing control and
treatment technology at actual plants is difficult to predict. A number
of factors are involved and the actual costs will depend, on the plant
situation. The usual considerations such as age and capacity will be
less important than such things as plant layout and the volume of water
used.
Cost Estimates
In this section are presented the assumptions used in calculating the
cost of implementing control and treatment technology.
Inflation Index
All final costs given in Table 12 are reported in 1971 dollars. The
basis for adjusting cost data is the Marshall & Swift Annual Index of
Comparative Equipment Cost. (2) Table 14 presents a listing of this
index for the years 1959-1971.
Cooling Water Assumptions
The data base used in estimating cooling water usage was obtained for 40
plants from returned questionnaires.
80
-------
"Bearing cooling" includes all machinery cooling in the plants,
including compressors, burner pipes, kiln bearings, grinders, etc.
Twenty-five plants report an average of 1,840 1/kkg (490 gal/ton). The
average daily production at these plants is 1,570 kkg (1,750 tons). The
flow is therefore 2,245 1/min (600 gal/min) .
The temperature rise was measured to be 28°C (5°F) at a number of
plants.
Cement cooler water reported for 21 plants was 945 1/kkg (224 gal/ton)
or 1,000 1/min (272 gal/min). This figure was verified by considering
the cement. The following data were used:
Change in T = 79°C (140°F)[From 140°C (250°F) to 62°C (110°F]
Change in T = 121°C - 43°C = 78°C (250°F - 110°F = 140°F)
Cp (clinker) =0.19 cal/°Cg
Heat removed from 1 kkg of cement is:
0.19 cal/°Cg x 1000 gKgcal/kkg cal x 78°C = 14,800 kgcal/kkg
(53,200 BTU/ton)
For the typical plant this is:
(1580 kkg/day x 14,800 kgcal/kkg)/1440 min/day = 16,200 kg cal/min.
(64,000 BTU/min)
If the temperature rise in the water is 14°C (25°F) and no evaporation
takes place, the flow required is calculated as
16,200 kgca1/min/(14°c x 1 kgcal/°Ckg x 1 kg/1) = 1160 1/min.
(310 gal/min) .
which is close to the actual average of 1060 1/min (280 gal/min)
reported. For present purposes, the flow for cement cooling was taken
as 1130 1/min (300 gal/min).
If both cooling streams are combined we have:
(bearing cooling) 2270 1/min o> 2.8°C (600 gal/min o>5°F)
(cement cooling) 1135 1/min a) 14°C (300 gal/min 325°F)
Combined 3405 1/min a 6.5°C (900 gal/min ffi 11.7°F)
To provide for extremely warm weather we will assume a temperature rise
of 8.4°C (15°F) .
Cooling Tower
81
-------
Guthrie (5) gives the base cost of a cooling tower for 8.4°C (15°F)
temperature rise and 3785 1/min (1000 gal/min) flow as $45,000. This
includes: cooling tower, concrete basin, pumps and drives, field
erection, and indirect costs. The bare-module cost will be 1.75 x
$45,000 or $78,750. Contingencies and contractor fees of 20X are added
for a total of $94,000, total installed cost (1968-$).
Cooling Pond Costs
Cost information provided by a single company on a spray pond to handle
their cooling water (the production rate is 1090 kkg/day ('1200 ton/day)
and flow is typical) is $100,000 total installed cost in 1965. For the
typical plant production of 1590 kkg/day (1750 ton/day) and a 0.6
exponential scaling factor, the cost for the typical plant would be
$125,000 (1965$) .
The size of an evaporative cooling pond required for this application is
determined by climatic conditions. For midsummer conditions of 50%
relative humidity, 25°C (77°F) average temperature, wind velocity of 8
km/hr (5 m/hr) , and solar radiation of 353 kgcal/hr/sq mi (.130 BTU/hr/sq
ft), the equilibrium temperature in a cooling pond would be 32°C (90°F).
With inlet temperature of 46°C (115°F) and outlet temperature of 38°C
(100°F), the area of the cooling pond would be 4100 sq m or about one
acre. For 24-hour holdup time the depth of the pond must be 1.19 m (3.9
ft) . Such a pond would cost about $15,000 (1971-$) (6) and should be
adequate for the typical plant.
Piping Costs
Estimates of piping costs were made for the typical plant illustrated in
Figure I by assuming that a cooling tower will be located near the kiln
area opposite the slurry tanks. The total length of piping will be
about 915 m (3000 ft), including 244 m (800 ft) from the raw mill to the
finish mill, 427 m (1400 ft) to connect the opposite ends of these
buildings (returns), and 244 m (800 ft) for twelve 20.3 (66.7 ft) runs
to the kiln area (feed and return to 4 piers, burner pipe and gas
analyzer).
A rough fitting count includes 28-90° ells and 4 valves. Allowances for
contingencies and 42 and 7 were used in calculating fitting costs.
Cost of piping was calculated on per lineal meter basis from Guthrie (5)
assuming 0.23 m (8" schedule 40) pipe, a 0.61 m (2 ft) wide by 1.83 m (6
ft) deep trench, machine backfilled with hand dressing. Summary
follows:
pipe (materials
pipe (installation.
Cost/m
15.25
Cost/lin ft
5.00
82
-------
yard and offsite) 7.62 2.50
trench (machine) 1.92 .63
backfill 3 1.18/cu m
(1.56/cu yd) JL.10 ^69_
Total 26.89 8782/lin ft.
Cost of fittings from rough count including 50% contingency:
42 ells material 3 $35.00 = $1,470
42 ells installed a) $11.50 = 483
7 gate valves material a) $500.00 =
3,500
7 gate valves installed 2) $60.00_^_420
Total fitting = $5,873
Therefore, total cost of installed piping is:
pipe 915 x 26.89 = 24,622
fitting .,5*873
$30,495
To allow for finding and plugging existing lines, a 50% contingency is
provided to bring the total cost of piping at the plant to about $50,000
(1968 dollars).
Because a cooling pond may have to be located some distance say 1,000 ft
from where the cooling tower would have been, the cost of piping is the
same as for the cooling tower plus and additional 610m at 26.89 per
m. The cost of piping a cooling pond is therefore
cooling tower piping $50,000 plus
610 m a $26.89/m 16,400
Total $66,400 (#1968-$)
Containment of run-off from dust piles
Thirty-five plants report an average of 0.156 metric ton of dust
collected per ton of product which for the typical plant amounts to 248
metric tons/day (273 ton/day). The bulk density of kiln dust may be
estimated as 1900 kg/cu m (117 Ib/cu ft) for a real density of 2400
kg/cu m (150 Ib/cu ft) and 22% void volume. The typical plant thus
collects and, in the extreme case, would pile 44,000 cu m per year
(57,000 cu yd). With an angle of repose of about 37°, a conical pile
2.4 hectares (6 acres) at the base and 65m (200 ft) high will amount to
about 590,000 cu m (700,000 cu yd) or more than enough for 10 years use,
a square 2.4 ha (6 acre) site will leave a perimeter of about 720 m
(2200 lineal ft). A 1.5 m (5 ft) high dike, 3 m (10 ft) wide at the
base and 1.5 m (5 ft) wide at the top will contain about 2400 cu m (3100
cu yd) which at $.91/cu m (7) amounts to a construction costs of about
83
-------
$2,000. Allow a contingency of 5056 and triple to provide a truck ramp
to a total of $10,000. An adequate 3 m (10 ft) sluiceway for overflow
of a 25 cm (10 m) 10" rain (extreme case) would add about $3,000 for a
total of $13,000 (1968-$) (7) for a 2.4 ha (6 acre) containment with a
ramp and sluiceway.
To handle the overflow in a wet climate where rainfall exceeds
evaporation by 75 cm (30 in) per year, a sulfuric acid neutralization
facility could be installed for about $15,000. Therefore, investment
cost of surface dust pile containment for the typical plant, with
neutralization of excess runoff will cost about $30,000.
Stack Gas Carbonation and Settling of Leachate Stream
One plant reported that a 1962 cost of $175,000 to install a stack gas
carbonation system with associated thickener and clarifying basins.
leachate streams. Adjustment for size of typical plant and inflation
brings the 1971 investment cost to $260,000.
Operating costs are reported as approximately $15,000 per year.
Estimated Cost of Electrodialysis
Assumptions used in estimating the cost of ED are as follows:
Flow 757,000 I/day (200,000 gal/day)
K2.SOU to be removed = 1.209 eq/sec (10 tons/day)
For technical details, Lacey & Loeb (30) should be consulted.
With the 85% efficiency given in Reference 30 the electric current
required is:
1.209 eq/sec x (96500 amp sec)/(O.85) = 137,000 amp
To estimate the number of stacks required, a polarization parameter
(i/N, where i = current density and N = normality) of 250 (conservative)
will be assumed. The current per cell pair is, therefore:
300 (ma/sq cm)/(eq/l) x 0.11 eq/1 x 2600 sq cm/pair
= 85.8 amp/cell pair
Since the total current is 137,000 amp, 1600 (137,000/85.8) cell pairs
are required, or 8 stacks of 200 cell pairs.
Quotation from Aqua Chem, Inc. (January, 1971)
WD-10-4 stacks (without membranes)
84
-------
50 cell pair stack $3,185 each
100 cell pair stack $4,225 each
Therefore, each additional 50 cell pairs will cost $1,040. A 200 cell
pair stack will cost $4,225 + 2,080 = $6,305. If 8 stacks are required
and 2 are on standby, cost will be 10 x $6,305 or $63,050 without
membranes.
A suitable rectifier will cost about $13,500 (46).
Pumps will cost $5,400 (2 in service, 2 standbys at $1,350 each).
Membranes will cost no more than $37.70 sq m ($3.50/sq ft), based on
1970 quotations from Tokuyama Soda Co., Ltd., of $18.85/sq m ($1.75/sq
ft) and from lonac Chemical Co., Inc. of $37.70/sq m ($3.50/sq ft). The
cost of the 1598 sq m (17,200 sq ft) of membranes needed is $50,200.
Required sand filters will cost about $18,000.
The cost of a 13.72 m (45 ft) clarifier was quoted by Eimco, Inc., to be
$23,000.
It is estimated that a total of four turbo-agitated gas-contacting tanks
will be needed for the two stages of carbonation. The cost of the four
tanks is estimated to be $16,000 (34).
Stacks $63,050
Membranes 50,200
Rectifier 13,500
Filter 18,000
Pumps 5,400
Secondary
clarifier 23,000
Carbonators 16T000
$189,150 Principal Items of Equipment (PIE)
Erection & Assembly = 3056 of PIE or $56,745. Contingencies of 10% PIE
and 10% E & A = 24,690 bringing the total to
PIE $189,150
EGA 56,745
Contin
gencies 24^690
$270,585
Engineering 27^050
(10X)
Total Investment for ED = $297,635 (1971-$)
Cost of Capital and Depreciation
85
-------
Since the return on assets for the cement industry varies from 3 to 10%
and the interest on vorrowed money is about Q%, capital costs are
assumed at a straight 8% per year over a ten year period. Depreciation
is on a 10 year straight-line basis.
Operating Costs
Operating costs for ED will consist of power, replacement membranes and
labor.
At a stack voltage of 200 and a current of 85.8 amps, power is 412
kwhr/day for ED, pumping will add about 60 kwhr/day. In addition, about
725 kwhr/day will be needed for the carbonators.
Some manufacturers of membranes guarantee a membrane life-time of 5
years for desalination, but a conservative estimate of 2 years life
expectancy was assumed. On this basis the annual cost of membrane
replacement is $25,100. Labor is estimated at 100 man-hour/stack/year
or about 1000 man-hours at $6.00/hr for a total labor of $6,000/year.
Annual operating cost of ED is therefore:
330 days power at 12/kwhr $3,850
Replacement of membranes and labor $3,850
For a total annual operating cost of about
$35,000 which is about 9% of the total
investment for ED.
86
-------
SECTION IX
EFFLUENT REDUCTION ATTAINABLE THROUGH 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
application of the best practicable control technology currently
available (BPCTCA). This technology is generally based upon the average
of the best existing performance by plants of various sizes, ages and
unit processes within the industrial category or subcategory or both.
This average is not based upon a broad range of plants within the cement
manufacturing industry, but based upon performance levels achieved by
exemplary plants. Consideration must be given to:
a. The total cost of application of 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 processes 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 technology within the process itself when the latter is
considered to be normal practice within an industry.
A further consideration is the degree of economic and engineering
reliability which must be established for the 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
87
-------
time of commencement of construction or installation of the control
facilities.
Identification of,BPCTCA
Nonleaching Subcategory
For the nonleaching subcategory of the cement industry, BCTCA is
recycling and reuse of wastewaters and containment of runoff from coal
piles and discarded kiln dust. An alternative to recycling and reuse is
the isolation of cooling water from possible sources of contamination.
In any case, the application of this technology will result in
essentially no discharge of pollutants. To implement this requires:
1. Recycling of cooling water through the use of
cooling towers, cooling ponds or completely
closed package systems, or isolation of cooling
water circuits from possible sources of con-
tamination by the use of enclosures, and control
of ambient dust within the plant, or reuse of
cooling water for preparation of slurry in wet-
process plants.
2. Containment and return-to-process of slurry spills
and slurry tank wash waters at wet-process plants.
3. Installation of suitable dikes to contain runoff from
coal piles and kiln dust piles or overflow from ponds
where waste dust is slurried or neutralization and
sedimentation of such runoff where it cannot normally
be contained.
4. Recycling or evaporation of water used to slurry
waste dust.
5. Storage piles of material other than high-alkali
kiln dust should be suitably diked to prevent the
discharge of pollutants to navigable waters in the
event of a 10 year 24 hour rainfall event.
Leaching Subcategory
For the leaching subcategory, BPCTCA is reduction of suspended solids
and neutralization of the leaching streams and application of the same
technology as outlined for plants in the nonleaching category for the
remaining streams. Application of this technology, netrualization and
sedimentation should result in a suspended solids loading of not more
than 0.15 kg/kkg (0.30 Ib/ton) of dust leached, and a pH of not more
88
-------
than 9.0. Since the amount of dust leached rather than the amount of
product produced, determines water usage for these streams, limitations
on the leaching stream are expressed in these terms.
In addition to the implementation required for the nonleaching streams,
implementation for the leaching streams requires:
1. Segregation of the leaching stream from all other
streams.
2. Installation of suitable facilities to neutralize the
leachate stream with stack gas to a pH of 9.0
3. Installation of a secondary clarifier or settling
basin to reduce suspended solids to not more than
0.15 kg/kkg (0.30 Ib/ton) of dust leached.
Limitations resulting from the application of this technology will not
result in a reduction in total dissolved solids. The extensive
treatment required to remove dissolved solids and the lack of current
practicable technology for treatment precludes setting limitations for
dissolved solids to be achieved by July 1, 1977.
Rationale_for_the_Selection_of_BPCTCA
Age and Size of Plants
As discussed in Section IV, the age and size of a cement plant do not
bear directly on the quantity or quality of wastewater generated.
The age of a plant is not very meaningful because new kilns and other
facilities may be added years after the original plant start-up.
Size of a plant, as measured by rated capacity, is not applicable
because variations in the type of equipment and plant management
practices are reflected in widely varying water requirements.
These considerations, coupled with verification of exemplary performance
at plants of various sizes and ages, indicate that size and age do not
bear on the practicality of zero discharge of pollutants.
Total Cost of Application in Relation to Effluent
Reduction Benefits
Based on the information contained in Section VIII of this report, the
total investment for all plants in the nonleaching subcategory would be
about $23,000,000 to achieve zero discharge of pollutants.
This figure is estimated on the basis of the known 151 plants in this
subcategory of which about 35 already report no discharge of pollutants.
89
-------
For the remaining 116 plants the typical cost of $200,000 per plant is
assumed. The 12 plants in the leaching subcategory will require a total
of about $5.1 million. This includes the same per plant expenditures as
above plus an additional $225,000 per plant for neutralization and
sedimentation facilities.
Thus, the estimated maximum expenditures for the industry as a whole are
about $28 million. On a per-plant basis, cost will range from 0.5 to 2%
of the $20 to $40 million estimated average cost of building a new
plant. The anticipated increase in operating costs, including
depreciation, amounts to about $0.11 per metric ton of cement (with a
current reported cost of from $15.11 to $21.20 per metric ton).
Processes Employed and Engineering Aspects
All plants in the industry use the same or similar production methods,
giving similar discharges. There is no evidence that operation of any
current process or subprocess will substantially affect capabilities to
implement best practicable control technology currently available.
Engineering Aspects of Control Technique Applications
This level of technology is practicable because at least 23 percent of
the plants in the nonleaching subcategory are now achieving the effluent
reductions set forth herein. The concepts are proved and available for
implementation, and may be readily adopted through adaptation or
modification of existing production units.
Of the plants in the leaching subcategory, none is presently achieving
the effluent quality that is specificed herein. However, each of the
control techniques is presently employed at individual plants and in
proper combination could achieve the prescribed effluent reduction if
applied at all plants in the leaching subcategory.
Process Changes
No process changes are envisioned for irrplementation of this
technology for plants in either subcategory.
Non-Water Quality Environmental Impact
The impacts upon non-water elements of the environment
include:
1. An increase in the solid wastes generated by the
industry due to collected sludge
2. A potential limited effect upon ambient air quality
90
-------
The former is relatively minor in view of -the large quantities of kiln
dust presently being wasted. The latter arises because the cost of
implementing the control measures necessary at leaching plants or at
plants that slurry discarded dust may encourage these plants to pile
waste dust which can create localized dust problems on windy days.
The enhancement to water quality management provided by these control
measures substantially outweighs the air and solids waste effects.
Moreover, techniques are available to control air-borne dust from piles,
and the solid wastes from this industry are relatively inert and are
acceptable as land fill and for uses such as sub-bases for secondary
roads and parking lots.
91
-------
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
(BATEA) . This technology can be based on the very best control and
treatment technology employed by a specific point source within the
industry category and/or subcategory or technology that is readily
transferable from one industry 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:
1. The age of the equipment and facilities
involved
2. The process employed.
3. The engineering aspects of the application
of various types of control technologies.
4. Process Changes
5. Cost of achieving the effluent reduction
resulting from the technology.
6. Nonwater quality environmental impact
(including energy requirements).
The Best Available Technology Economically Achievable also assesses the
availability in all cases of in-process controls as well as the control
or additional treatment techniques employed at the end of a production
process. A further consideration is the availability of processes and
control technology at the pilot plant, semi-works, or other levels,
which have demonstrated both technological performances and economic
viability at a level sufficient to reasonably justify investing in such
facilities. Best Available Technology Economically Achievable 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
93
-------
up to and including no discharge of pollutants. Although economic
factors are considered, the costs for this level of control are intended
to be top-of-the-line of current technology subject to limitations
imposed by economic and engineering feasibility. However, Best
Available Technology Economically Achievable may be characterized by
some technical risk with respect to performance and costs and, thus, may
necessitate some industry development prior to its application.
Identification of BATEA
Nonleaching Subcategory
For plants in the nonleaching contact subcategory, the effluent
limitations reflecting this technology are essentially no discharge of
pollutants as developed in Section IX.
Leaching Subcategory
Based upon the information presented in Sections III through VIII of
this report, the degree of effluent reduction attainable through the
application of BATEA is concluded to be essentially no discharge of
process wastewaters to nayigable streams.
This technology consists of treatment and reuse of water from the
leachate streams within the operation. Implementation requires the
development of a practical system for the concentration and removal of
the alkali salts in the leachate stream. Such a system, outlined in
Section VII, might consist of electrodialysis, evaporation, or a
combination of both. While the technical and economic feasibility of
these methods remains
to be demonstrated in this industry, the components of this technology
have been sufficiently demonstrated to justify the development work
despite the technical and economic risks.
94
-------
Rationale for Sglectipn of BATEA
For nonleaching plants, the rationale was developed
in Section IX.
For leaching plants, the effluent limitation of "essentially no
discharge" is based on the availability of transferrable technology,
electrodialysis. While this technology is not presently in use in the
cement industry, it is considered the best available and economically
achievable because:
1. It is currently is use on a commercial scale
for recovery of salt from sea water, a more rigorous
operation.
2. The total costs of implementing this technology,
about $300,000 investments and $35,000 annual
operating cost, appear to be within the range of
economic, practicality in view of the pollution
reduction benefits obtained.
3. The process appears to be technically sound as
developed in Section VII.
95
-------
SECTION XI
NEW SOURCE PERFORMANCE STANDARDS
AND PRETREATMENT STANDARDS
New Source^Performance Standards
A new source is defined as "any source, the construction of which is
commenced after the publication of proposed regulations prescribing a
standard of performance." Technology to be utilized for new sources has
been evaluated by considering the control technology identified as Best
Available Technology Economically Achievable in Section X and
considering the availability of alternative production processes and
operating methods.
The effluent limitation for new sources in the nonleaching subcategory
is essentially no discharge of pollutants to navigable waters as
developed in Section IX. For leaching plants, the standard is reduction
of suspended solids to less than 0.15 kg/kkg (0.30 Ib/ton) of product
and pH to 9.0 as developed in Section IX.
The technology utilized should be that defined as Best Practicable
Control Technology Currently Available. After the necessary
developmental work is performed the technology defined as Best Available
Technology Economically Achievable for leaching plants may eventually
provide a more effective and economical treatment system and the
performance standards should then be revised accordingly.
Pretreatment Standards
In addition to the effluent limit for new sources, those wastewater
characteristics have been identified which would interfere with, pass
through, or otherwise be incompatible with a well designed and operated
publicly owned wastewater treatment plant. A determination has been
made of the guidelines for the introduction of such wastes into the
treatment plant.
97
-------
SECTION XIII
REFERENCES
CEMENT MANUFACTURING
1. "The Making of Portland Cement," Portland Cement Association (1964).
2. "Portland Cements," Portland Cement Association (1971).
3. H. S. Frolich, "The Development of Cement Manufacture in the Last 50
Years," Pit_and_Quarry_, 59, 301 (Oct., 1966).
4. P. K. Mehta, "Trends in Technology of Cement Manufacture," Rock
Products^. 73, 83 (March, 1970) .
5. J. D. Wilson, Bendy Engineering Co., Letter to G.A. Morneau,
Southern Research Institute, May 24, 1973.
STATISTICAL AND COST DATA: CEMENT INDUSTRY
6. "U. S. Industrial Outlook 1972 with Projections to 1980," U. S.
Department of Commerce, 1972, p. 12.
7. R. A. Grancher, "Cycling with Cement," Rock Products,75, 66 (Dec.
1972) .
8. R. A. Grancher, "Cement's Second Century," Rock Products, 7_4, 100
(Oct. 1971) .
9. Anon., "Cement: Increase Anticipated for Cement Demand and Plant
Capacity Planning," Rock_Products, 74, 54 (Dec. 1971).
10. "World cement Directory, 1972," International Publications Service,
New York, 1972.
11. "American Cement Directory 1972," Bradley Pulverizer Co.,
Allentown, Pa. (April, 1972).
12. S. Levine and E. W. Stearn, "The Year Ahead 1973," Rock Products,
75X 53 (Deceirber, ]9?2).
13. J. P. Wynen, "Economics of Cement Plant Design," Rock Products, 74,
78 (Feb. 1971) and 74, 70 (March, 1971).
101
-------
KILN DUST UTILIZATION AND DISPOSAL
14. B. Kester, "The Alkali Probelm," Presented to the Portland Cement
Association, General Technical Committee, (Fall, 1972).
15. Anon., "Potash from Cement at the Riverside Portland Cement
Company," Metallurgical and Chemical_ Engineering, 701, (June 15,
1917).
16. J. M. Wolfe, "Kiln Dust-Properties and Handling," Pit and Quarry,
55X. 136 (March, 2964) . ~~
17. C. H. Goller, Jr., "Is Dust Leaching Worthwhile," Pit and Quarry,
59A_122 (August, }966).
18. W. R. Dersnah and C. F. Clausen, "Can that Dust be Used Again?" Pit
and_2uarry., 50 (Sept., 1958).
19. T. L. McCubbin, "Dust Control Techniques for a Portland Cement
Plant," Minerals Processing, 10, 24, (May, 1969).
20. F. W. Cohrs, "How the Newer Plants Handle Kiln Dust Disposal," Rock
ProductSj^T^ 50 (Nov., 1971).
21. Termachos Patzias, "Extraction of Potassium Oxide from Cement Kiln
Flue Dust," Doctoral Dissertation, Wayne State University (1959).
22. G. C. Lindsay, "Don't Throw Away Dust," Rock Products,65, 87 (July,
1962) .
23. "Panel Session on Dust Returned to Rotary Kilns," Portland Cement
Association (Jan., 1966).
AIR AND WATER POLLUTION STUDIES: CEMENT INDUSTRY
24. "The Cement Industry: Economic Impact of Pollution Control Costs,"
Prepared by the Boston Consulting Group, for the U. S. Environmental
Protection Agency (Nov., 1971).
25. "Background Information for Proposed New-Source' Performance
Standards: Steam Generators, Incinerators, Portland Cement Plants,
Nitric Acid Plants, Sulfuric Acid Plants," U. S. Environmental
Protection Agency, Office of Air Programs (Aug., 1971).
26. "The Industrial Wastes Studies Program: Summary Report on the Flat
Glass, Cement, Lime, Gypsum and Asbestos Industries," U. S.
Environmental Protection Agency (Jan., 1972).
102
-------
27. "Regional Guidance for Permit Preparation: Cement, Lime, Gypsum,
Asbestos and Flat Glass Industries, U. S. Environmental Protection
Agency (Sept. 21, 1972) .
28. "Industrial Waste Study Report: Flat Glass, Cement, Lime, Gypsum,
and Asbestos Industries," Prepared by Sverdrup & Parcel and
Associates, Inc. for the U. S. Environmental Protection Agency
(July, 1971).
29. T. E. Kreichelt, "Atmospheric Emissions from the Manufacture of
Portland Cement," U. S. Department of Health, Education, and Welfare
(1967).
WASTEWATER CONTROL AND TREATMENT
30. R. E. Lacey and S. Loeb, "Industrial Processing with
Membranes," John Wiley and Sons, Inc., New York (1972).
31. Henri Chidiac, "Water Pollution Control at Dundee's
Clarksville, Mo., Plant," Pit and Quarry, 60, 86
(Oct. 1968) .
32. J. D. Wilson, "Controls Spark Waste Water Dilemna,"
E2£fc_Products, 2£r 92 (March, 1973).
33. G. Rey, W. J. Lacey, A. Cywin, "Industrial Water Reuse:
Future Pollution Solution," Environmental Science^and
Technology, 5, 763 (Sept., 1971).
34. K. M. Guthrie, "Modern Cost Engineering Techniques,"
McGraw-Hill Book Co., New York (1970).
35. W. L. Patterson, et.al., "Estimating costs and Manpower
Requirements for Conventional Wastewater Treatment
Facilities," U. S. Environmental Protection Agency
(Oct., 1971) .
36. "Pretreatment Guidelines for the Discharge of Indus-
trial Wastes to Municipal Treatment Works," Prepared
by Roy F. Weston, Inc. for the U. S. Environmental Protec-
tion Agency (Nov. 17, 1972).
37. "Commodity Data Summaries," U. S. Department of Interior, Bureau of
Mines, pp. 114-115 (Jan., 1973).
38. Chemical_Marketing_Re£orter, 203, (Feb. 12, 1973).
103
-------
39. E. L. Quinn and C. L. Jones, "Carbon Dioxide," Reinhold Publishing
Co., New York (1936).
40. "Methods for Chemical Analysis of Water and Wastes," U. S.
Environmental Protection Agency (1971).
41. "Water Measurement Manual," U. S. Department of the Interior,
Bureau of Reclamation (1971).
42. Japanese Patent 224611 (August 31, 1956), "Process for concentration
of inorganic electrolyte solutions."
43. Japanese Patent 217865 (November 28, 1955), "Electro-dialyzer for
concentration of electrolytic solutions."
44. Japanese Patent 236354 (November 4, 1957), "Process for
concentrating potassium salts."
45. T. Nishiwaki, "Concentration of Electrolytes Prior to Evaporation
with an Electromembrane Process", Chapter 6 in Industrial Processing
with Membranes , R. Lacey and S. Loeb, editors,
John Wiley and Sons, Inc., New York (1972).
46. Private Communication, J. D. Wilson, Bendy Engineering.
47. Letter of J. D. Wilson, Bendy Engineering to G. A. Morneau, Southern
Research, May 24, 1973.
48. "Marshall & Swift Annual Indexes of Comparative Equipment Costs,
1953 to 1971," Chem.Eng;., Nov. 13, 1972, p. 170.
49. Bruce Kester, private communication, Missouri Portland Cement Co.
50. J. Perry (ed.), "Chemical Engineers Handbook (3rd Edition)," McGraw-
Hill Book Co., New York, 1950.
51. K. M. Guthrie, in "Modern Cost Engineering Techniques," Edited by H.
Popper, McGraw-Hill Book Co., New York, 1970.
52. W. L. Patterson and R. F. Banker, "Estimating Costs and Man
power
Requirements for Wastewater Treatment Facilities," Final Report to
EPA, Contract 14-12-462, October, 1971.
53. H. E. Mills, in "Modern Cost Engineering Techniques," Edited by H.
Popper, McGraw-Hill Book Co., New York, 1970.
54. R. E. Lacey and S.Loeb, "Industrial Processing with Membranes,"
Wiley-Interscience, New York, 1972.
104
-------
SECTION XIV
GLOSSARY
peg init ions and Terming logy
Alkali: A substance having marked basic properties, generally sodium or
potassium oxides or hydroxides in kiln dust.
A quantitative measure of the capacity of liquids or
suspensions to neutralize strong acids or to resist the establishment of
acidic conditions. Alkalinity results from the presence of
bicarbonates, carbonates, hydroxides, volatile acids, salts, and
occasionally borates, silicates and phosphates. Numerically, it is
expressed in terms of the concentration of calcium carbonate that would
have equivalent capacity to neutralize strong acids.
B§.3._House : A dust collection system in which the dust is trapped when
dust- laden air is passed through porous bags.
Bengf iciatign; Improvement of the chemical or physical properties of a
raw material or intermediate product by removal of undesirable
components or impurities.
Blowdown: A periodic discharge to prevent the buildup of dissolved
solids due to evaporative loss in cooling towers and boilers.
BOD __ .IBiochemical __ Oxygen __Demand^; An indirect measure of the
concentration of biologically degradable material present in organic
wastes. It is the amount of free oxygen utilized by aerobic organisms
when allowed to attack the organic matter in an aerobically maintained
environment at a specified temperature (20°C) for a specific time (5
days) . It is expressed in milligrams of oxygen utilized per liter of
liquid waste volume (mg/1) or in milligrams of oxygen per kilogram of
solids present (mg/kg = ppm = parts per million parts) .
105
-------
Burning: Combustion of fuel, or sintering or near-fusion in a kiln,
resulting in chemical combination of the raw materials and formation of
clinker.
c§ffi§!lt__C-22.l£E: Equipment for cooling finished cement after grinding.
May consist of a water-jacketed screw conveyor with a water-cooled
impeller schaft and blades, or a vertical cylinder, with the outside
cooled by running water and along the inner surface of which a thin
layer of cement is moved by centrifugal action.
Clarifier: A large tank or pond used for holding turbid water for a
sufficient time to allow solid materials to settle.
Clinker: The fused product of a kiln which is ground to make cement.
COD jChemigal Oxygen Demand): An indirect measure of the biochemical
load exerted on the oxygen assets of a body of water when organic wastes
are introduced into the water. It is determined by the amount of
potassium dichromate consumed in a boiling mixture of chromic and
sulfuric acids. The amount of oxidizable organic matter is proportional
to the potassium dichromate consumed. Where the wastes contain only
readily available organic bacterial food and no toxic matter, the COD
values can be correlated with BOD values obtained from the same wastes.
Cooling Pond: A pond, sometimes equipped with sprayers, used with
recycle cooling water systems to reduce the temperature of the water by
evaporation.
Cooling Tower: A mechanical device, normally elevated, used with
recycle cooling water systems to reduce the temperature of the water by
evaporation.
Dissolved Solids; Solids dissolved in water and not removed by
filtration.
Pry Process; Process for cement manufacture in which the raw materials
are ground, blended, stored, and conveyed to the kiln in a dry form.
106
-------
Effluent: The wastewater discharged from a point source (plant).
Electrostatic Preqipitator: Collector for fine dust, particularly in
kiln gases. Dust laden air is passed through a large chamber where the
dust particles are ionized by contact with chains or rods connected to
one pole of a high-voltage rectifier, and then attracted to and
collected on the sides of tubes or plates connected to the other
(grounded) pole. Collectors are rapped periodically to discharge dust.
Flocculation; Accumulation or agglomeration of fine particles
masses or floes of suspended solids to facilitate settling.
into
Gas_Analy_zer: An instrument using the principle of chemical combination
or catalytic combustion in which a sample of gas may be collected and
analyzed for oxygen, carbon dioxide and combustile materials.
Insufflation: Practice of adding collected dust to the coal in a burner
pipe for return to the kiln.
Kiln: A metal cylinder 2.5 to 8.5 m in diameter and 65 to 250 m in
length, slowly rotating (60 to 90 r.p.h.) and inclined approximately U
cm per m toward its discharge end: for burning cement raw mix into
clinker. Lined with refactory bricks and often equipped with internal
heatexchangers.
Kiln_Dust: Fine particles of cement and raw materials
kiln and collected by air-pollution control equipment.
blown from the
The overflow discharged from a leaching operation.
Leaching: A process for removing alkalies from kiln-dust by washing
with water, so that the dust can be reused to make cement.
Loading; The quantity of a constituent added to the water used within a
point source and subsequently discharged, normally expressed in amount
per unit of production.
107
-------
Outfall: A point at which the effluent from a point source is
discharged into a navigable waterway.
Overflow; Excess water from an operation, tank, pond, etc. that is
recycled or discharged, generally after settling of suspended solids.
p.H; The symbol for the logarithm of the reciprocal of the hydrogen ion
concentration, expressed in moles per liter of a solution, and used to
indicate an acid or alkaline condition. (pH 7 indicates neutral; less
than 7 is acid; greater than 7 is basic).
Portland^Cement; The product obtained by pulverizing clinker consisting
essentially of hydraulic calcium silicates, to which no additions have
been made subsequent to calcination other than water and/or untreated
calcium sulphate, except that additions not to exceed 1.0 percent of
other materials may be interground with the clinker at the option of the
manufacturer, provided such materials in the amounts indicated have been
shown to be not harmful by tests carried out or reviewed by committee C-
1 on Cement of the American Society for Testing Materials (A.S.T.M.).
Process^. Water; A general term applied to the water used in operations
directly related to the manufacture of a product, and sometimes
contacting the product or raw materials, as distinguished from cooling
water, boiler water, and all other water used in ancillary operations.
In cement manufacturing the term is most commonly applied to the slurry
water used at wet-process plants.
RAPP Applications: Applications submitted to the Corps of Engineers to
obtain a Permit for Discharge into Navigable Waters under the 1899
Refuse Act Permit Program.
Recycled Water; Water which is recirculated for the same use.
Reused Water; Water which is used for one purpose and then reused for
another purpose.
108
-------
Sedimentation; The removal of suspended solids contained in wastewater
that will separate by settling when the carrier liquid is held in a
quiescent condition for a specified time interval.
Settling Basin: A pond, lagoon, or tank also referred to as holding or
sedimentation basin in which suspended solids are removed sometimes by
the addition of flocculants.
Sludge: The accumulated settled solids deposited from the sewage or
other wastes, raw or treated, in tanks or basins, and containing
sufficient water for form a semiliquid mass.
Slurry.: Suspension of ground raw materials in water at wet-process
plants.
Su§_£ended_Solids: Solids that either float on the surface of, or are in
suspension in, water and which are largely removable by filtering or
sedimentation.
Thickener: Large basin for slurry of raw materials ground with excess
water. Suspended particles settle to bottom (underflow), whereas
surplus water (overflow) runs over edge.
Total Solids: The residue remaining when the water is evaporated from a
sample of water, sewage, other liquids or semi-solid masses of material
and the residue is then dried at a specified temperature (usually
103°C).
Underflow: Carrier water used in an operation to transport solids to
another operation or disposal site.
Volatile_Solids: That portion of the total or suspended solids residue
which is driven off as volatile (combustible) gases at a specified
temperature and time (usually at 600°C for a least one hour).
Waste-Heat_Boiler; System of boilers and economizers, heated by the hot
exit gases from kilns, used to generate electricity.
109
-------
Waste Load; The quantity of a constituent present in wastewater
expressed in units of concentration, amount per day, or amount per unit
of production. Raw waste load is the quantity of a given constituent in
the wastewater prior to treatment. Net waste load is the difference
between the quantity of a constituent in the intake and discharge
waters.
Wet ^Process; Grinding, blending, mixing and pumping cement raw
materials mixed with water. Wet process is chosen where raw materials
have a high water content, which would make drying before crushing and
grinding difficult.
Wet Scrubber: Type of dust collector in which dust-laden gases are
cleaned by passing through a fine spray of water.
110
-------
P1
^*
o
rt
C
Pi
O
O
«^
ro
01
P-
O
3
3
O
rt
Pi
3
p1
rt
P-
*O
M
P-
(D
l-i
pi O A
DJ 01 pi
h(
~ (D
01
cr p-
O 3
H 0
rt cr
*- ro
01
iS
p-
3
o o c\
10 <£> .ti
p- 0 Ul
it^ *-4 K)
^
3 X* 01
g1®
O
3
£! O P-
PI 3 ro
(D \
01
(!) P
(D P)
rt H
(D
p-
3
O
. .
^Q
P)
P
iQ
(D
—
iQ 01 P-
P-
MilQ
ft
O
•
O
00
OOP"
O 3 rop-33H
o 3* o 3 PI PI cr
c ro o c P" P"--
H p- 3 rt
^< rt O. ro G G
3 3
p- p-
ft rt
D
0
3
Oi
o o o wtBtrni
33lrj'Opirt'^pcCMiMiHi-3CroO
3 M 01 3 G G p-
ffi P- l-h Hi \ Mi
iQ 3 ft rt P- rt
cr
o
• p"
Ol KJ
Ul P1 to LJ
ONJOOOJOLnCTlOOOP'OOOOOJO
OU1--JO-JW OWCJO-~JOU1N)K)U1^
OJiC^it^O^GOO^VDlON) (OO1LJ1O O
LO Ln Ul l_n >t. 1 OO OOUlM^J, Ul
4^ — IP1 00 IA)
w to
-
pt O "7? P1 P1 3 oOh-'OOOX'^^'O CT
ft 3 ^ ^^ OP PPPU3iQX*PPi
3 01 ih
ro o 33300 3
O 3 \X Pi PI
3 3 P- H
p- p-\
3 3 *•
n
3
LjQ
P1
P-
01
cr
G
3
p-
ft
*M
Q*
cr
ro
^
P-
PI
rt
p-
O
3
O
O
3
ro
h(
Ul
P-
o
3
cr
cr
H
ro
p-
PI
rt
p-
O
3
3
p
I — •
rt
p-
13
**N
s~+
a
^Q
j— i
P-
01
cr
G
3
p-
ft
01
*-*
cr
^
n
o
•z
H
O
3
o
en
W
ro ro \Q
rt rt P
Q H Pl
w o ro
rt O
o ro
3 3
01 rt
P-
^ Q
P1 ro
0 rt
o ro
o n
01
^
p-
M
O
VQ
h
&
3
01
ifl rt
P 3
pi O
ro 13
JJ*
3 ro
ro M
rt ro
ro 01
M
pT
tr
01
o
1 — '
P
rt
ro
P- P
P" cr
0 P-
ro
rt 3
ro ro
^ rt
ro
l-f
01
V —
fi
pi
*<
p- rt ro
P- 3 3
O O rt
^ -3 3
p> 3^ ro
3 ro rt
01 M ro
ro h
01 01
P- p- P-
P1 rt rt
o ro ro
PI 01 01
ft ^x
rt 01
w ro
o
o
3
p,
ro ro p
rtiQ CT
ro H P-
01 ro
o
n ro
ro 3
rt P-
p-3
M ft
PI ro
a H
ro 01
P- P
rt tr
ro P-
01
£J
ro
rt
ro
h
01
&&
p- P-
o o
3 3
ro ro
n- rt
ro ro
h H
01 01
^\ \^
3 3
p- p-
3 3
P C
rt rt
ro ro
p- P- ro
P- M ft
O O K
MHO
p; p;
3 3 rt
0
0 1 3
pi 01
P- 0
O pi
l-i P1
P-O
ro H
01 P-
\ ro
X1 01
P-
M
o
tQ
M
0)
3
&ro
0
P-rt
H
3 (D
ro 01
rt
ro
h
01
s
ro
rt
p-
o
G
3
p-
rt
1-3
0
O
tr
rt
p>
p-
3
3
ro
rt
h
p-
o
c
3
p-
rt
01
— '
111
-------
nvir^nTertal ?r-.>t region Agency
Lilirarv, '. ,'-•'' -''
1 }
------- |