United States Industrial Environmental Research EPA-600/2-79-003
Environmental Protection Laboratory January 1979
Agency Research Triangle Park NC 27711
Research and Development
&EPA Process Water Quality
Requirements for Iron
and Steel Making
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
EPA REVIEW NOTICE
This report has been reviewed by the U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify that the contents necessarily
reflect the views and policy of the Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-79-003
January 1979
Process Water Quality
Requirements for Iron and
Steel Making
by
S. Bhattacharyya
I IT Research Institute
10West 35th Street
Chicago, Illinois 60616
Contract No. 68-02-2617
Task No. 2-1
Program Element No. 1BB610
EPA Project Officer: John S. Ruppersberger
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
-------
PREFACE
Water use in the iron and steel industry is basically
non-consumptive. More than 90% of the 95,000 to 150,000 liters
(25,000 to 40,000 gal) of water required per tonne of steel is
returned to large water bodies. But during usage, the water
is polluted and the polluting waters contaminate the environ-
mento Significant efforts are now being made to accomplish the
following:
- Lessen use of water through recycling and
treatment.
Acquire greater knowledge and understanding
of the effect of water purity level on equip-
ment and product quality.
This brief study focuses its attention on the second goal.
The study reveals significant gaps in information relating water
and product qualities, on the one hand, and water quality and
equipment productivity, on the other. Areas of research are
identified to close these data gaps.
ii
-------
ABSTRACT
This study was directed to develop information on minimum
water quality requirements for the different unit processes in
iron and steel making, identify the data gaps, and recommend
research efforts needed to obtain the required information,,
A combination of literature study, plant visits, and discussions
witt} the American Iron and Steel Institute, equipment manufac-
turers, water chemical suppliers, and consultants was used in
this studyo
„ The central finding of this study is that a ateel plant
neither allocates water on the basis of individual processing
units nor recycles water from each processing unit on individ-
ual and separate circuits„ In fact, the steel plants do not
record water flowing in and out of each individual unit, nor
do they analyze these waters.
1 -In a steel plant, water is normally used as-received and
lime-softened; in a few cases, special treatments are given.
Water is distributed to clusters of processing units usually
located in close proximity. The distributed water is of a few
basic qualities, two to four, and analyses of these basic qual-
ities; are made, Higher quality water is infrequently used in a
cascading manner for lower quality applications'.
In some U,S, as well as foreign steel plants, recycling ex-
ceeding 98% of recirculating water is practiced without any sig-
nificant equipment problem and product quality deterioration.
When equipment problems arise, the present water control tech-
nology can usually solve the problem. The modern equipment is
rugged in design and able to accommodate significant water im-
purities with the help of chemical controls;
Very little .information is available on the effect of water
quality on product quality. Water recycling and reuse problems
are intimately related to steel plant Waste recycling and air
pollution problems, and data on these are also limited.
Several research and study recommendations have been made
to close the data gaps. One significant recommendation is basic
data generation on flow and water analysis at individual conT.
sumption points through the installation of flow meters and
sampling points.
This report is submitted in partial fulfillment of Contract
No. 68-02-2617 by IIT Research Institute under the sponsorship
of the U.S, Environmental Protection Agency. The report covers
.the contract period 31 August 1977 to 5 January 1978,
iii
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CONTENTS
Preface ................... p ..... ii
Abstract. . . „ . . ..... ..........•••« ii:i-
Figures ........ „ . . . ..... ........ v
Tables. ...... ..... . ....... ....... vi
Acknowledgments ................ ..... . vii
!„ Introduction . . ........ ......... j_
2. Conclusions. .......e.p. ........ 2
3. Recommendations. ........ ..•• .......... 3
4. United States Iron and Steel Industry, ....... 5
Capacity and Distribution ............ 5
Producing Units of an Integrated Steel Plant. o
Water System in an Integrated Steel Plant . . ^Q
50 An Approach to the Study ..... ........ 37
Introduction. .....''........... 37
Open Literature ..... ... P ...... 17
Iron and Steel Plants ............. ig
American Iron & Steel Institute (AISI) ,.-.-. -,*
Equipment Manufacturers . , . „ . .-...-.. in
6. The Basic Findings and Discussions ........ 20
Kaiser Steel Corporation (KSC) . . . . . . . . ' ^n
Armco Steel Corporation (ASC) ........ 25
Colorado Fuel & Iron Steel Corporation (CFI), 31
Discussions with Groups and Individuals , . , 33
Information from Equipment and Water
Chemical Suppliers ....... »....„ 41
Foreign Steel Plants. ............ 43
Recycling of Steel Plant Wastes and Its
Relationship to Water Usage ........ 46
Some Strip Quality Problems Associated
with Water Quality. ............ 50
7. Reuse and Recycling of Water in the Iron and
Steel Industry ......'.....p...... 53
References. ............ .o..o.Po..,P..0 55
Appendices
A. Statistical Highlights of the U.S. -Iron and
Steel Industry . . . . . . . . • « = • . . . . . . 59
iv
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FIGURES
Number
1 Geographical distribution of the UttS. iron and
steel industry„ ."'..«,."«,.'.. 8 ...". „."<><,.' 6
2 Total UoS., .steel production „ «, . . <. „ = , ,• , , ,, „ 7
3 Process unit interrelationships „ , , „ 0 „ 0 , . „ „. 12
s
4 Schematic arrangement of the water-treatment
system at Fairless Works of United States Steel
Corporation o.oooooooo°ao<>oooo°oo 14
5 Water supply and usage at Appleby-Frbdingham
for the year ending March, 1972 • „ „ 0 « o . , » o <, = 15
6 Kaiser Steel water systems„ . „ 0 0 » , o « <, » o 0 » 21
7 Water supply„and distribution to major production
areas, Armco Steel Corporation0 „. o 9 ,,'... 9 . 0'. 27
8 Simplified schematic of the wastewater system,
Armco Steel Corporation „ 0 . , » . . , . . « . . , o 28
9 Steel melt shop water system, Armco Steel
Corporation «, „ . = o » . o = <,<,.»» , . 9 o „ , . 30
10 Mill water distribution, Colorado Fuel & Iron,
JLj I ^T OC«*OOOOO*O*OOOOO5><^°OOOOO sJ ^M
11 Simplified material flow diagram, Colorado Fuel
& Iron Pueblo plant ».. 9 ° ° *««>>« 36
- , "i
12 Strip mill'cooling water recirculation systems,
Hoesch Hiittenwerke, Dortmund, West Germany* . . o . ,- 45
13 .Particle size distribution for representative
samples of ferruginous wastes „ . „ . . . . . . , <, . 51
14 Simplified flow sheet for recycling „ „ . „ „ „ e . . 55
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TABLES
Number Page
1 The Top 10 Steel Companies of 1976 ......... 9
2 Forecast of Water Consumption at Appleby-
Frodingham for Year Ending March, 1976 ....... 16
3 Kaiser Steel Corporation Average Influent and
Effluent Water Analysis at the Water Treatment
Plant, 1976. ..................... 22
4 Analyses of Water of the Four Major Water
Streams, Kaiser Steel Corporation. ......... 24
5 Mill Water Distribution and Blowdown, Armco
Steel Corporation. ...... ........... 26
6 Average Analysis of Effluents to Dicks Creek,
Armco Steel Corporation, Period 10/1/77 to
10/31/77 ....... ......... 27
7 Analysis of Plant Influent (1976), Colorado
Fuel & Iron. 34
8 Analysis of Plant Effluent for October 1977,
Colorado Fuel & Iron 35
9 Water Analysis, National Steel Corporation,
Weirton. . . . . 38
10 Water Analysis, U.S. Steel FairfieId Works,
Alabama .................. 39
11 Water Analysis, Youngstown Sheet & Tube,
Indiana Harbor ...... , ........ „ „ . „ 40
12 Mold Deposits in Continuous Steel Casting. . . . . . 42
13 Continuous Steel Casting Problems, . „ „ 44
14 Permissible Impurities in Industrial WaStewater
from Rolling Mills, Hoesch Iron & Steel Works,
Dortmund, West Germany ... .......... 00 47
15 Unit Requirements for Water, USINOR, Dunkirk,
France ........ ...... ... . . . „ . o 43
16 Sources and Rates of Production of Iron-Bearing
Wastes, British Steel Corporation (BSC), 1975. ... 49
vi
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ACKNOWLEDGMENTS
We gratefully acknowledge the cooperation of the following
steel plants in supplying data on water flow and quality:
1. Kaiser Steel Corporation, Fontana, California
2. Armco Steel Corporation, Middletown, Ohio
3c Colorado Fuel and Iron Steel Corporation,
Pueblo, Colorado
Mr. William Benzer of American Iron and Steel Institute,
Washington, D«,C0, was very helpful in supplying published mate-
rial and arranging the meeting with the AISI Environmental Com-
mittee o
Cooperation of Calgon Corporation and equipment manufactur-
ers, such as Koppers, Loftus, Wilputte, Morgan, and ASEA, were
of assistance in this study„
We thank Hydrotechnic Corporation, New York City, for
allowing us the use of their updated water flow diagrams of
several steel plants and basic water quality data obtained by
them on a current EPA program.
Mr0 Walter Zabban, Chief Engineer, the Chester Engineers,
Pittsburgh, Penn0, was a consultant to this study, and discus-
sions with him on any topic related to water treatment and usage
in iron and steel industry were very helpful,
Mr0 John Ruppersberger, the EPA Project Officer, is to be
specially thanked for going out of his way in helping us to
remove roadblocks in data gathering.
VI1
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SECTION 1
INTRODUCTION
During "1967-76, the IKS. steel industry produced a total of
1-1/5 billion tonnes (1-1/3 billion tons) of steel and directly
employed 510,000 workers annually„ Statistical highlights of
the U.S. iron and;steel industry are given in Appendix A. Enor-
mous quantities of water were needed at every stage of produc-
tion. Less than 1070 of this water was literally consumed in the
process, and,the,rest o£ it' wae returned to the environment»
In most instances, the returned water was harmful to some aspect
of the environmento This study focuses on one aspect of water
usage, namely, on the minimum quality requirements for process
water for the various iron and steel making units. Once infor-
mation on current water quality requirements is identified and
quantified, it will be possible to direct research efforts to
modify these requirements with lesser water usage as a goal and
establish meaningful minimum water quality requirements without
compromising product quality or equipment performance and pro-
ductivity. The complexity of steelmaking technology, the in-
dustry's somewhat aging equipment, its highly capital-intensive
nature, the magnitude of the risks associated with equipment
failure, and the monetary losses associated with off-quality
products support the need for establishment of a;very thorough
data base of minimum water quality requirements that will en-
hance in-plant water reuse and recycling programs resulting in
reduced wastewater discharge0
a One tonne = 1000 kg = 2205 Ib0 One ton = 2000 Ib,
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SECTION 2
CONCLUSIONS
The central finding of this study is that an integrated
steel plant does not allocate water on the basis of individual
steel processing units or point source categories as defined in
EPA effluent guidelines. Water is distributed on the basis of
a few basic qualities (as low as two) to clusters of plant units.
These basic water qualities have, in most cases, progressive but
significant differences., The water qualities are derived not
solely on the basis of equipment maintenance/productivity de-
mands or product quality requirements, but on the quality and
quantity of the water available and the existing distribution
systems. In certain areas, steel plant effluent is the only
water source to keep alive a stream and instead of significant
recycling most of the water is treated and discharged on a once-
thr9ugh basis.
The equipment used in the steel industry is rugged in nature.
Furnaces and machinery can be designed to tolerate acceptable
compromises to water quality when properly implemented. How-
ever, a lack of knowledge of water chemistry and flow rate en-
tering or leaving an equipment unit makes it virtually impossible
to establish meaningful quality adjustments without encountering
unacceptable risks of plant breakdown and product quality degra-
dation. This enormous data gap in water quality information at
each plant unit needs to be bridged. As a minimum, it will be
necessary to install flow meters at the inlets of all major
water-consuming points, and to have incorporated in that scheme,
sample points for water collection and analysis. These flow
and analytical data can then be utilized to determine the tol-
erance level of equipment and the products they produce. On
this basis, further modification can be made for development of
effective and economical wastewater treatment technology and
total recycle. Outlines of research programs to fulfill this
need are given in Section 3.
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SECTION 3
RECOMMENDATIONS
Minimum water quality needs for different plant processes/
subprocesses are virtually nonexistent, and need to be defined
before significant in-plant water reduction programs can be
initiatedo The information needed to make an intelligent de-
cision regarding minimum water quality for the process has two
aspects:
1. Effect on process equipment
2. Effect on product quality and recycling
of steel plant metallics0
To study the effect of water quality on process equipment,
a two-level research effort is needed,, At the plant level, the
basic information regarding water quality and flow should be
gathered systematically,, This should be relatively easy and
economically acceptablec At the laboratory level, short- and
long-term studies on the effect of water quality on equipment
performance must be conducted to obtain an understanding of the
minimum water quality that can be sustained by the equipment
without loss in normal service Iife0
A study of the effect of water quality on product quality
is more difficult because it will require production of some
off-quality products. The scppe of the research effort can be
limited to finishing units of a steel plant because the effect
of water quality on coke production, pig iron, and steel ingot
is negligible«, The most significant effects of water quality
are associated with finished steel products, primarily the
coated and cold-rolled flat products. In steel finishing, there
is also a significant paucity of knowledge, and studies are re-
quired independently as well as with collaboration of the steel
industry. A few research suggestions are given below:
1« Establish correlation between non-adherence
of paints on auto body panels and their
accelerated corrosion with localized sur-
face contamination resulting from residual
oil and/or iron salts left on the sheets
after cleaning.
20 Determine the relationship between water-
oil emulsion quality and oil-^burn phenomena
on cold-rolled steel sheets„
-------
3. Develop oily sludge treatment to make them
suitable for recycling without causing air
pollution and equipment operation problems,
4. Determine if the use of dry film graphite
lubricant is an acceptable alternative to
oil and grease.
5c Develop heavy metal removal technology
particularly with emphasis on total re-
cycling of vacuum degassing water.
6. Advance technology for chromium recovery
from plating liquor and sludge.
7. Determine degree of built-in overdesign
in existing equipment, to enable efficient
operation with lower water quality than
currently used.
8= Techno-economic study to replace existing
cooling tower system for cooling non-
contact cooling water of blast furnace
stave and tuyere cooling, and EOF hood
and lance cooling with completely deminer-
alized water in a totally enclosed circuit
with air-cooled heat exchanging facility.
9. Use simulation techniques and accelerated
tests to determine the effect of water
quality on steel and iron making equipment.
10. Develop a computer model incorporating
material and heat flow in making one ton
of finished steel to predict minimum water
requirement per ton steel produced using
combinations of different water qualities
and partial or total recycling.
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SECTION 4
UNITED STATES IRON AND STEEL INDUSTRY
CAPACITY AND DISTRIBUTION
From less than 10.9 106 tonnes (12 million tons) in 1900,
UoS. raw steel production reached a high of 137 x 106 tonnes
(151 million tons) in 1973= The production of 116 x 106 tonnes
(128 million tons) in 1976 increased to about 119 x 106 tonnes
(131 million tons) in 1977„ To provide a perspective, in 1976
the steel productions of Japan, European Economic Community
(EEC), and USSR were 107, 134, and 147 million tonnes, respec-
tively, (1) out of a total world steel production of 683 x 106
tonnes (753 million tons).
While the above tonnage figures between the countries are
all comparable, there are significant differences in the produc-
ing units. Japan has virtually rebuilt its capacity during the
last 25 years and has the most modern and productive equipment,,
Much of the EEC and USSR plants are more modern than the USA's,
EEC plants do not have,to serve far-flung communities as they
are very tightly clustered in the heart of Western Europe„ Un-
til the late 60's, USSR plants had similar distribution, two
major areas, one in the Ukraine and the other at the Urals,
centered in Magnitogorsk, about 2400 km (1500 miles) apart.
• The majority, 65 to 70%, of the U0S0 steel industry is situ-
ated in a six-state region bordering the Great Lakes, as shown
in Fig0 I.'2) 'They obtain their need of billions of liters of
daily water requirements from the Great Lakes and the large
river complexes in these states„ Because of ample supply of
clean water, the industry had very little problem in meeting the
water needs of steel production 0.
The present installed UoS0 steel capacity is about 145 x 10s
tonnes (160 million tons). Various growth projections have been
made, and one such estimate is shown in Fig0 20^) According to
Fig, 2, by 1980 an installed capacity of about 168 x 106 tonnes
(185 million tons) will be needed to produce 151 x 10s tonnes
(167 million tons) of raw steel if all the additional million
tons of steel demand are not to be lost to imports. In 1977,
a record import of 17 million tonnes (24 million tons raw steel)
took place,,
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LOCALITIES WHERE RAW STEEL IS MADE;
STEEL INDUSTRY EXTENDS FROM COAST TO COAST
IN THE UNITED STATES
("""} States producing steel mill products
^"~~^ (Plant sites not indicated)
• Centers producing raw steel
MAJOR DEPOSITS OF IRON ORE AND COKING COAL
Q IRON ORE - Deposits currently or recently
mined or presently being developed
£ COKING COAL - Coked at present time or
has been coked in the past
ALASKA £ O
ALASKA - No steelmaking facilities in Alaska
HAWAII - Honolulu
Source: American Iron and Steel Institute,
"Geography of Iron and Steel In the United States"
ALABAMA
Birmingham
Fairfield
Gadsden
ARIZONA
Tempe
CALIFORNIA
Emeryvl1le
Etiwanda
Fontana
Long Beach
Los Angeles
Torranee
Union City
COLORADO
Pueblo
CONNECTICUT
Bridgeport
DELAWARE
Claymont
FLORIDA
Tampa
GEORGIA
Atlanta
HAWAII
Honolulu
ILLINOIS
Alton
Chicago
Chicago Heights
Granite City
Kankakee
Lemont
Morton Grove
Peoria
South Chicago
Ster)ing
INDIANA
East Chicago
Fort Wayne
Gary
Kokono
New Castle
West Cheater
KENTUCKY
Ashland
Newport
Owensboro
MARYLAND
Baltimore
Sparrows Point
MICHIGAN
Dearborn
Ecorse
Ferndale
Trenton
Warren
MINNESOTA
Duluth
St. Paul
MISSISSIPPI
Flowood
MISSOURI
Kansas City
NEW JERSEY
Roebl1ng
NEW YORK
Buffalo
Dunk!rk
Lackawanna
Lockport
New Hartford
Syracuse
Watervliet
NORTH CAROLINA
Croft
Monroe
(2)
Figure 1. Geographical distribution of the U.S. iron and steel industry^
OHIO
Campbel1
Canton
C i nc i nna t f
Cleveland
Lora i n
Mansfield
Hiddletown
Portsmouth
Steubenvl I le
Warren
Youngstown
OKLAHOMA
Sand Springs
OREGON
Portland
PENNSYLVANIA
Al iqulppa
Beaver Fa I Is
Bethlehem
Brackenridge
Braddock
Braeburn
Br.dgevMIe
Burnham
Butler
Carnegie
CoatesvtIle
Duquesne
Erie
Fair less Hills
FarreU
Harrisburg
Hous ton
Irvine
Ivy Rock
Johnstown
Latrobe
HeKeesport
Midland
Milton
Monaca
Monessen
Munhall
New Castle
Oakmont
Philadelphia
Phoentxv! He
Pittsburgh
Reading
Steel ton
TitusvHIe
Washington
West Homestead
RHODE ISLAND
PhJlipsdale
SOUTH CAROLINA
Cavce
Georgetown
TENNESSEE
Harriman
Knoxville
TEXAS
Fort Worth
Houston
Lone Star
Longv i ew
Pampa
SeguSn
Vlnton
UTAH
Geneva
V.I RG IN I ft
Chesapeake
Newport News
Roanoke
WASHINGTON
Seattle
WEST VIRGINIA,
Huntington
Weir ton
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20(
190|
180|
170|
16o|
15o|
140[
13(
12(
IK
S ioc
o
6(
51
5(
I
I
£_»
Trendline (Best estimate; takes
» into account increasing.
^ . yield with growth;of
continuous casting)
O Raw Steel Production, U.S.
X" —X Total Shipments of Steel
Products, U.S.
A A 1970 to 1976 from Ref. 2,
1977 data estimated
181
163
145
127
109"
91 |
82 I
14-1
O
03
68 S
59
50
41
1950
1955
1960
-J,
7T~~ TTffTT T7ST
32
1945
Year
TT7T
Figure 2. Total U.S. steel production.
(3)
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Using a quantitative economic analytical technique, Mo and
Wang(4) projected'a 2.9% average annual growth rate to 140 mil-
lion tonnes (154 million tons) finished steel, equivalent to
about 181 million tonnes (200 million tons) of raw steel. ^Even
assuming an import contribution of 17 million tonnes (19 million
tons) of finished steel (raw steel 24 million tonnes, 26 million
tons), a domestic raw steel production of 158 million tonnes
(174 million tons) will require 172 million tonnes (190 million
tons) of raw steel capacity.
Thus, it appears that a minimum of 163 million tonnes (180
million tons) of raw steel capacity will be required in the next
3 to 5 years. In other words, almost 4 million tonnes of raw
steel capacity must be added every year for the next few years,
apart from modifications, modernization, and environmental ex-
penses. On the other hand, any new and modernized capacities
designed with environmental considerations in mind will appre-
ciably reduce the problems associated with water pollution.
The major steel producers are all integrated mills, i.e.,
they have their own coke plants, blast furnaces, steel melt
shops, and mills within a single boundary and authority. Table 1
lists the top ten steel companies and their production, revenue,
and employment costs. (•>)
PRODUCING UNITS OF AN INTEGRATED PLANT
Pig iron (also called hot metal) is produced in tall re-
actors (blast furnaces) from iron-bearing raw materials such as
ores, pellets, sinter and scrap, fluxed with limestone. Coke is
required to provide energy for smelting and is the reducing med-
ium for iron production. Modern blast furnaces are very large
units, as large as 10,000 tonnes/day, A 4000 tonne/day blast
furnace may require as much as 200 million liters (50 million
gallons) of water daily. Large piles of raw materials are us-
ually stored in the open with complete environmental exposure.
Coke is made in closed rectangular ovens by destructive
distillation of raw crushed coal. In addition to coke coke
ovens produce a valuable gas and many chemicals which are nor-
mally recovered. These are ammonia, tars, light oils, phenol
and benzene. In addition, fine particles of coal and'coke are
generated in profusion. Coal stored in large piles is also
exposed to weather.
An agglomerated product, called sinter, is often a sub-
stantial portion of iron-bearing charge in a blast furnace
This product is made from natural and crushed fines of iron ore
coke, limestone, mill scale, and flue dusts, much of which will'
otherwise be discarded as waste. The sinter plant consists of
a long traveling grate furnace on which the mixture is burned
under conditions to obtain a desired product.
8
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TABLE 1. THE TOP 10 STEEL COMPANIES OF 1976
Raw Steel
Production,
millions_of
Company
U.S. Steel Corp.
Bethlehem Steel Corp.
Armco Steel Corp.
National Steel Corp.
Republic Steel Corp.
Inland Steel Corp.
Jones & Laughlin
Steel Corp.
Lykes- Youngs town Corp.
Wheeling-Pittsburgh
Steel Corp.
Allegheny Ludlum
Steel Corp.
Sales
Revenues ,.
billion
tonnes
25.7
17.1-
6,9
908
8.7
7.2
6o3
4o6
3.5
0.7
(28.3)
(18.9)
(7.6)
(10,8)
(9.6)
(7,9.)
(7oO)
(5.1)
(3.9)
(0.8)
8
5
3
2
2
2
2
1
0
0
$
.725
.305
.165
.841
.,546
.401
.052
. 643
.936
.902
Employment
Cpsts
billion
3.
2.
0.
0.
0.
0.
0.
0.
0.
0.
.$. '
578
314
974
885
911
738
735
592
375
304
% of
sales
41 .0
44.1
30.9
31.2
35.8
.•*
30.9
35.8
36.5
40.1
33.6
Net
Income ,
million
$
410.
168.
123.
85.
65.
104.
44.
19.
3:.
30.
3
0
7
7
9
0
4
0
2
7
Long-Term
Debt,
billion
1.
1.
0.
0.
0.
0.
0.
0.
0.
0.
$
960
023
667
744
372
480
349
673
183
-
177
Figures in parentheses are in million tons
-------
The molten pig iron contains significant amounts of impuri-
ties, and to produce steel these are oxidized and fluxed away in
basic oxygen converters (EOF), open hearths (OH), and electric
arc furnaces (EF). Until 1968, OH was the major steelmaking pro-
cess requiring less of pig iron and more of scrap. In 1976,
over 607«> of raw steel was produced by EOF, projected to increase
to 807o by 1980. EOF requires 70% of its charge to be pig iron.
The impact of this technological turnabout is reflected in in-
stallation of large blast furnaces (Bethlehem, 7600 tonnes/day
and Inland, 6300-9900 tonnes/day) and coke ovens to feed them,
both requiring very large quantities of cooling water.
Simultaneously, with the advant of EOF, continuous casting
of molten steel has made rapid progress, over batch casting of
large ingots. While traditional ingot casting required very
little cooling water, continuous casting requires a very high
volume of water, often of different purity levels, one of which
requires special treatment. The other water stream gets highly
contaminated with scale.
Vacuum degassing of molten steel is also a significant de-
veloping technology. The nature of the process is such that
some of the metallic elements including heavy metals are pulled
out and enter the waste stream after gas cleaning.
After casting, the large ingots or continuous cast slabs
and billets are heated and shaped by passing through large cy-
lindrical or shaped rollers. The heating in large furnaces and
soaking pits requires a significant amount of water for cooling.
In the rolling process a very large volume of water is needed
for cooling the rollers, bearings, and the products, as well as
for cleaning the thick scales from the product by high-pressure
water jets before the start of rolling. Moreover, oil is used
in oil-water emulsions for cold rolling. Thus, a complex water
stream is generated from the shaping operation.
In addition to shaping, many of the flat products are sup-
plied with coatings of zinc, tin, lead-tin alloy, chromium, and
polymers. To prepare for coating, the steel materials are
cleaned of surface scales by acid pickling. Thus the coating
operations generate a complex wastewater stream containing acids
and their salts plus metal and organic coating materials—and
this stream is one of the most difficult to handle.
An overall flow pattern of the steelmaking process is
shown in Fig. 3.(2)
WATER SYSTEM IN AN INTEGRATED STEEL PLANT
While Fig. 3 shows the complex pattern of material flow in a
steel plant, the water system to accomplish efficient operation
is far more complex, as shown in Fig. 4.v°) in Figa 4 the fin-
ishing units of sheet and tin mill and tube plant form'the most
complex water system consisting of acids, oils, and scales
Eventually, sludge is removed, pickle liquor is dumped, and
10
-------
flocculator oil skimmings are burned. The hot strip mills and
the tube mill form another complex while the coke oven, blast
furnace, and open hearth form a third complex,, The fourth com-
plex is essentially the power plant.
The diversity of water treatment, its routing and usage,
may be even more clearly seen in the schematic water use pattern
shown in Fig0 5 for Appleby-Frodingham Steel Co. of the U,K,(7)
The circulating water amounts to 150,000 liters/tonne of steel
(36,000 gal/ton)a of which 3100 liters/tonne(750 gal/ton) are
consumed. Of the 3100 liters/tonne consumption, about 90% is
lost in evaporation and the remainder is discharged to water
bodies. About 40% of the circulating water is used under lime-
softened condition, another 40% as received, and the remaining
207o with special treatments.
With recirculation and usage, contaminant levels tend to
build up in the water streams but do not change the basic nature
of the treated water which is fed to the different plant units,
as shown in Fig0 5. The anticipated consumption of water per
plant units for a production level of 4,5 million tonnes ( 5 mil-
lion tons) per year is given in Table 2, The consumption rate
of 24,000 liters/min is equivalent to 2900 liters/tonne of steel,
i,e,, about 700 gal/ton. The blast furnace complex accounts
for a quarter of the consumption, followed by 14% in coke ovens
and 9% at the sinter plant. In other words, all activities
directly related to pig iron production account for 51% of the
total consumption. It has been pointed out earlier that with
the technological switch from OH to EOF, more pig iron will be
needed to produce a ton of steel and thus will increase water
consumption. This increase can be offset by judicious recycling
and design of water treatment units,
/ON
At the ARBED Esch-Belval works in Luxemburgw' with a raw
steel production capacity of 104 million tonnes/year, the spe-
cific water consumption is betwen 1200 and 1700 liters/tonne of
steel, i,e,, between 290 and 400 gal/ton. All the water recir-
culation systems of the works are of closed design laid on a
cascade basis.
At the USINOR's Dunkirk plant^ ' in France, at 8 million
tonne/year production stage, a water consumption of only 1800
liters/tonne is planned, i,e0, 430 gal/ton. At both USINOR and
ARBED, great attention is given to establish a rain-water net-
work which is used for cooling pig iron, granulating the blast
furnace slag, spraying the slag and cinder pits, etc.
1 gallon = 3.785 liters
11
-------
ScftpR«cycli
Meui
Scrap
Electric
£1
i|
i
t
K
si
•SI
£1
\
S
si
I
1
?
5
u.
I
Caitmt
fir PHI
*.-§ '51 S i = »
4—4
r~
Continuous
Catling
fiillti Unit
Continwout
Caiting
Slab Unit
?
N__T
ji -i r i - *
el 51 *- i S =
LEGEND:
In-plant flows
Scrap recycle
1 Flows from outside
OFlow streams joined to obtain common
cost to following process
Figure 3. Process unit interrelationships<2>
12
-------
_
Primary Breakdown 14
To Blooms
-
To Bill»U vii Bloomi
Primary BrMfcdown ^
ToSlibs
Purchaitd
W00*'11^^^ " B
t
r
\
1
•
— 4
co'rnl f
r
V
V
'
> — .
A Heavy Structutsli '7
J ^*" end Re«<
_», Wife Product..
Nailt
•: i
18
Bar end Rod
.:
Pgrehawd
Continuous Cast Blooms
Continuous C«it
B.ilen
Contmuoui Cut
SJ»bj
Dir«* Shipnwntl of Ingot*. SJ*bi, (3.3%)
BtlMU. Blooms
_ Heavy Sltunurels. ,7.9.41
13.2%)
Barn, Light StructmU
S«amlB«Pipe,
,„,*,
J^ColdKniihed ,,.9%|
p-j Galvonliint"|—fc- Ga
[ I Tin Plating and 271 t j.
j | Other Plated Products I _!'
i 6.4X1
Hot Rolled
Sheet .n
-------
SHEET AND TIN MILL
LADLE COKE
SHOP PLANT
NATIONAL HOT STRIP MILLS
DEL A W A HE
I , V E It
Figure 4. Schematic arrangement of the water<• treatment system
at Fairless Works of United States Steel Corporation,^)
(Copyright 1971 by United States Steel Corporation)
-------
e&rtrortion
River An.cholme .
Varies with seasons
impure and very hard
64 BO
Ashby Villz
Sewage effluent of
consistent quality
hard
4310
Token during year
fo of licensed amount
Tftotnwnt.
Proportions as used
Wiiortj of m3 per annum
Otportmental consumption
Sinter
plant
Furnace
cooling
Gas cleaning 25 2%
Blowing 142%
ioo"%
Iron making
5135-2-36°/o of
circulating water
49OO
757%
Temporary
hardness
removed by lime
softening
Used
raw
2IQO
487°/o
Plant drainage
and rainfall
Vories with rainfall
high dissolved solids
5000
North Lincoln
boreholes
Potable quality
very hard
37IO
_North Lindsey
"Water Board
Total I95OO
(excluding
NLWB supply
which is
undefined)
3I3O
626%
Lime ,', .Lime
-"nsa
Used
raw
Lime softened
55BO 41-3%
2:94
Used raw
4545 337%
239
3255
87-8%
HIS Total I350O
Lime soda
plus base
exchange
Used
row
Fully
softened
,2325
Row
D5O
122
056
29% ,27%
• 14-7%
subsequently
distilled
Total I35OO
litres per min
7-11 million m9
Rolling mills
H8O-25O%ot
circulating water
Steel production
1775-204%
circulating water
Steam rising
2O2O-673%of
steam generated
Quenching 39%
Cooling 61%
oo%
Coke ovens
1820-548% of
circulating water
Domestic
.820
Power generation
365-114% of
circulating water
Miscellaneous
385
Figure 5.
Water supply and usage at Applebv-Frodingham
for the year ending March, 1972.(7)
15
-------
TABLE 2.
FORECAST OF WATER CONSUMPTION AT APPLEBY-FRODINGHAM
FOR YEAR ENDING MARCH, 1976
Consuming Plant
Sinter plants
Blast furnace cooling
Blast furnace gas cleaning
Blast furnace blowing
Coke ovens
Steelmaking - EOF
Continuous casting
Rolling mills
Electrical power generation
Steam raising
Domestic purposes
Slag quenching
Miscellaneous users
Total
Water
liters/min
avg
2,225
2,450
1,545
2,590
3,540
1,500
1,000
1,590
1.225
2,880
1,000
1,045
1,410
24,000
Consumption
percent
of total
9.3
10.2
6.4
10.8
14.7
6.2
4,2
6.6
5.1
12.0
4.2
4.4
5.9
100.0
16
-------
SECTION 5
AN APPROACH TO THE STUDY
INTRODUCTION'
The objective of this study was to develop data on minimum
water quality requirements for different unit processes of the
iron and steel industry,, One would logically assume that much of
this information is'available in the open literature, a careful
analysis of which should identify the data sought for and reveal
any gaps to be filled. Thus, the four basic questions posed in
the work assignment could be answered adequately.
It was also expected that a wealth of information must be
available with the water management divisions in the steel in-
dustry which could be obtained by correspondence with several
steel plants followed by plant visits and discussions, where
necessary. In addition, the iron and steel industry trade asso-
ciation, the American Iron and Steel Institute (AISI), must be
collecting this information and would have a generous data bank
to share with IITRI for this study.
Furthermore, because equipment is designed to meet certain
performance criteria relating to heat transfer, flow rate, pres-
sure, temperature, scaling, fouling, and erosion, the equipment
manufacturers must have a set of guidelines regarding water qual-
ities such as pH, temperature, total dissolved solids (TDS),
total suspended solids (TSS), alkalinity and similar parameters
to enable them to design the equipment system. Thus, the equip-
ment manufacturers were considered another information source
for this study.
Unfortunately, on each of the above three counts the out-
come has been less than satisfactory, if not disappointing.
OPEN LITERATURE
Within the time frame of this study, a thorough manual and
computer-aided search was made for water quality information in
the steel industry, and the result has been disappointing. The
computer search yielded no significant specific information. A
manual search of relevant sources resulted in some data collec-
tion, mostly non-specific in nature. The reason is that, till
17
-------
the mid 1960's, water quality, whether going into a processing
unit or being thrown out to a water body, was not considered to
be significant in the steel industry because of ample supply,
low cost, and lack of knowledge and concern about environmental
impact of polluted water. Thus, hardly any data on water quality
levels at individual plant units were kept, let alone published.
In view of heightened environmental awareness and EPA ef-
fluent guideline regulations, considerable data are now being
collected on discharges. But since there are no EPA requirements
for water quality documentation at equipment inlet and recycling
streams, there is still very little relevant information avail-
able in the literature. A strong case can be made for such doc-
umentation. Most of the data in the literature pertain to flow
rate, pH, TSS, IDS, and alkalinity on water streams as a,whole
for the entire plant or for a large combination of units. No
specific data are available in the open literature on inlets
and outlets of 30 specific plant units., defined as point source
categories in the effluent guidelines A iU-lz; jn each of these
30 units there are dozens of separate water streams and consump-
tion points, and obviously no information is available at these
subunits or locations,
IRON AND STEEL PLANTS
The majority of the steel plants are clustered around the
Great Lakes (Fig. 1)„ The assurance of ample clean water was a
major consideration for'their location. An equally important
reason was the availability of these water bodies as recipients
of the polluted discharge from the steel plants. Thus, in most
plants, the basic treatment was nil or minimal—only elimination
of excess suspended solids. The water was used as received or
merely lime-softened, if required.
' A few plants are located in water-scarce regions; a prime
example is Kaiser Steel Corporation (KSC) at Fontana near Los
Angeles. Some plants are in arid/semi-arid regions; an example
is Colorado Fuel and Iron (CFI) at Pueblo. KSC was constructed
in the 40's and specifically designed for extensive water recyc-
ling. Thus, they kept possibly the best set of data on water
quality.
In the Ohio valley, river pollution from steel mill wastes
became a source of major community concern long before the
national concern expressed in the creation of EPA. Armco Steel
Corporation (ASC), Middletown, Ohio, initiated a set of measures
for extensive water recycling, and their data collection on ef-
fluent is significant. "
18
-------
AMERICAN IRON AND STEEL INSTITUTE (AISI)
AISI, unfortunately, has no centralized data bank on water
quality requirements in the steel industry, and was unable to
help IITRI in providing these data. They readily gave IITRI a
collection of their published studies and requested IITRI to
contact individual steel plants to obtain the necessary data. A
meeting was held with AISI Environmental Committee at Pittsburgh.
EQUIPMENT MANUFACTURERS
*. • •* <. ' •
Several invidual steel plant equipment suppliers were
contacted for design information on water quality for,their
equipmento The general response was that they did not have any
specific requirement unless it was a power plant or some such
special unite They design their equipment based on steel plants'
water supply information, which is very general in nature. Thus,
the source of equipment supplier did not result in significant
data generation,,
Most recently some information regarding water quality on
product quality was presented in a society meeting and also
appeared in a weekly metalworking publication. These data are,
possibly, the most specific to date on this subject.
Our approach to data collection and information developmert
covered all possible avenues. Because significant and critical
data on minimum water quality requirements for process water and
product quality are not there, it will be necessary to undertake
research studies to obtain more specific data and this is recom-
mended later.
19
-------
SECTION 6
THE BASIC FINDINGS AND DISCUSSIONS
The information reported in this section was obtained ba-
sically from plant visits, open literature, and discussions with
individuals.
Three steel plants were visited:
Armco Steel Corporation (ASC), Middletown, Ohio
Colorado Fuel and Iron Steel Corporation (CFI),
Pueblo, Colorado
Kaiser Steel Corporation (KSC), Fontana, California.
KAISER STEEL CORPORATION
KSC recycles about 98% of its water. Its net consumption
is 4600 I/tonne (1100 gal/ton).t13' Of this only about 960 I/ton
(230 gal/ton) is finally discharged to a municipal wastewater
plant, which treats it for discharge to the ocean. This excep-
tionally low discharge of 960 I/tonne is much better than the
best data from steel plants such as ARBED, Luxemburg; Dunkirk,
France; and Appleby-Frodingham, U0K0, mentioned earlier. How-
ever, the total requirement will increase to about 3400 1/min
(9000 gpm), and discharge between 5700 and 7200 1/min (1500 and
1900 gpm) with the addition of new BOF and continuous casting
units now under construction,,
Much has already been written about KSC's cascade system
of water usage. In this system water of the highest quality
once used is reused in the next system requiring lower quality
and so on. Four such systems are used along with some special
water systems, as shown in Fig. 6.(-*-4-) The system was planned
this way from the start because of the arid nature of the region.
The analyses of influent and effluent streams at the water
treatment plant are given in Table 3. Though flow charts show
that the water stream from the domestic reservoir flows directly
into the industrial reservoir, a difference in the analyses
between these two qualities exists. It is noted that in the
solid contents and hardness level, the industrial water is
higher. This is so because the plant is not on a level ground
20
-------
from
I
UNo
1
i
1 WELL No. 2
INDUSTRIAL RFS
— . ' f
COOLING
TOWER
No. 19
^
COOLING
TOWER
No. 10
i
TIN
MILL.
SHEET
CALVG.
COLDROLl
SHEET
1 i ,
WCKl«
MHI9 ,
1
_ __,.. ,, v... . , . , . — _
[WATER TKEATMENT PLANT}
«
DOMESTIC RtSERVOm
•s
F.RVOIR , '
.^ .
I i
b
I,MKSTICSI:RVIC
.• \ •«<•-.;.'.. -»" r<.
& milU; fire |iro-
ectlon & hnilxnpe
X
I SEWAGE TP.F.ATMEN
1 PLANT
1 *
k,
COOLING TOWERS No. 2A
A
PLATE, PIPE.
& SLAB. MILLS:
power room &
Tumace cooling
COLD MILL & PI
MILL-pkktolin
PIPE MILL
hydraulic
descaling
PE
it
1
JL GATE VALVE
y iwwmallv ckwl
WATER
SOFTENER
_, PLANT
r '
i.
?
» » '
j_. . -i M . — __ j
. POWER PLANT
WASTE HEAT
I .
-_J71
COOLING
TOWER No. 3
1
POWER PLANT
cooling system & misc.
f— 1
ICOOLINC TOWERS No. 2U|
„ B..BT t
PLATE. PIPE. STRUCTURAL &
SLAB'G MILLS: HOT SCARFING MILL
1 scale flush & general use; pig casting
1
»
J, J, & 1
COOLING TOWER No. 14
motor-room cooling water
1
M/
HOT STRIP MILL
AIR COMPRESSOR
MOTOR ROOM
,, J, I— J
FURNACE
Nrn. 1.2,3
' ' > '
, Jr
[COOUNG TOWER No. 15 |
(excess to wastewater
treatment plant)
* w ' ' <"
| COOUNG TOWERS No. 1
*_
BLAST FURNAC
No. 1.
mtfc DI &M-T
E | OP
* *TT 1.
EN HEARTH | i > JJ
— ,i „ rr
HOT STRIP MILLi
general use |
I
FONTANA
SLAG
(contractor)
r
STORM
DRAIN
RECOVERY
T
BAROMETRIC
CONDENSER
ICOOLINC TOWER NO. i2| I
BLAST
FURNACE
No. 3
COOUNG
ITOWER NO. is
BLAST
FURNACE No. 4
WASTRWATFR
TREATMENT
PLANT
_c
3E
COKE PLANT-
[BENZOL PLANT! LIQUOR COOLING COILS
ICOOLINC TOWER
I No. 8
BLAST
FURNACE No. 2
^ *fr r
COOLING TOWER
No. 17 _ -
J, i
BLAST
FURMACE
No. 4
gas washer
BLAST
FURNACE
No. 4
Sll| pit)
4f » r
COOLING TOW ERl
i N°-",
A- i
»L ^
FUR.1ACE
tfut wainer
BLAST
FURNACE
No. 3
llJJ pltt
in" ••
fy V
COO LING TOWER
No. 9
i I
BLAST
FURNACE
No. 2
BLAST
FURNACE
No. 2
s!i< pin
SUPPLY*
(TREATMENT;
/DOMESTIC
| SYSTEM
NDUSTR1AL
SPECIAL
YSTEMS:
HIGHEST
IMDUSTRIAL
SPECIAL
2nd
INDUSTRIAL
' INDUSTRIAL
SPECIAL
[ACID DISPOSAL PLANT |
i
NONRECLAIMABLEWASTEWATER LINE
LOWEST
INDUSTRIAL
WASTE
TREATMENT.
> DISCOS SL
& KEUSE
/ SYSTEM
Figure 6. Kaiser Steel water systems.
(14)
21
-------
TABLE 3. KAISER STEEL CORPORATION AVERAGE INFLUENT AND EFFLUENT
WATER ANALYSIS AT THE WATER TREATMENT PLANT, 1976U4)
Item
Effluent
DomesticIndustrial
Influent Reservoir Reservoir
PH
Alkalinity (as CaC03>, mg/1
Phenolphthalein
Methyl orange
Total Solids, mg/1
Total Dissolved Solids (TDS),
mg/1
Total Suspended Solids (TSS),
mg/1
7.7
0
159
234
229
8.5
4
57
129
124
6.8-8.9
0
68
160
149
11
Non-COo Hardness (as CaCO.,) ,
mg/lj J
Total Hardness (as CaCOo) ,
mg/1
Chloride, mg/1
Sulfate, mg/1
Sodium, mg/1
Calcium, mg/1
Magnesium, mg/1
1
148
11
23
23
48
7
9
54
12
19
•PI
-
*
29
75
15
15
-
-
*
Ft
Calcium/magnesium ratio of 6 remains unchanged through treat-
ment.
22
-------
and, depending on demand, water from one water stream may flow
back into the industrial reservoir on its way to the next tier
of water usage„
Though KSC has the best wa^er usage record, its water qual-
ity data for individual plant units are neither specific nor
extensive,, The additional water quality data available are for
cooling tower waters„ Analyses of the four major system streams,
from the highest to the lowest, are given in Table 4»
Data in Table 4 show how significantly water quality de-
grades with use. TDS builds up by about an order of magnitude
between streams 1 and 4. Chloride increases approximately 20-
fold, hardness 9-fold, and sulfate 7- to 8-fold.
Even with this system there are some areas where equipment
problems have been encountered. At the tin mill, reverse
osmosis (RO) is used where the^TDS is brought down from domestic
water supply level of 150 to 5 mg/1. The TDS buildup interferes
with the emulsion stability, and before the use of RO, the emul-
sion had to be thrown out in a couple of days creating a signif-
icant pollution problem. At present, the emulsion is stable for
a couple of weeks. From this one example, it becomes dear that
application of existing technology at the proper areas can sig-
nificantly reduce the water pollution problem.
Only a few cases of effect of water quality on product
quality were identified during the discussion. Speck rust on
cleaned and oiled plates was initially thought to arise from
poor water. But now it is considered to arise from water drop-
lets from the nearby scrubber, carrying traces of acid.
In an indirect manner, oily mill scale sludge is a water
quality problem. Because the adhering oil to the mill scale
cannot be easily separated, its use at the sinter plant is hin-
dered. If used, the burning creates an air pollution problem—a
blue haze. Proper water treatment of the scale-laden water
should provide a solution to the problem.
Recovery of chromium from plating waste will be desirable,
both for use of chromium and reuse of the water. -However, at
present, lack of proper technology compels KSC to dump them in
solar ponds where, in a few years, natural concentration from
20 mg/1 to 16 g/1 may enable them to recover chromium.
From the viewpoint of this task, not much information re-
garding water quality at specific units was obtained. KSC has
extensive information on incoming water and cooling tower water
analysis, and follows a practice which may be considered the
best in the world. However, it is to be remembered that in
spite of this exemplary practice, the flow rates shown for all
streams are based on calculations. We were given to understand
23
-------
TABLE 4. ANALYSES OF WATER OF THE FOUR MAJOR WATER STREAMS,
KAISER STEEL CORPORATION
Quality
Level
1
(highest)
2
3
4
(lowest)
Use
Non- contact
cooling
Rolling mills
Blast furnace
Steelmaking
Sintering
Coke ovens
Blast furnace
gas cleaning
PH
7.4
7.7
7.3
7.1
TSS,
mg/1
23
50
39
*
50
TDS,
mg/1
283
300
550
3000
Hard-
ness,
mg/1
108
120
200
900
Total
Chlo-
Alkal ini ty , r ide ,
mg/1
51
70
50
220
mg/1
53
50
170
. 1100
Sul-
fate,
mg/1
49
70
100
370
Can be as high as 300 mg/1.
-------
that in the entire plant there may not be more than three water
flowmeters in operation. Thus, one significant data gap at KSC
is simply lack of adequate flow information. This data gap
coupled to absence of.water analysis for individual plant units
makes it difficult to predict additional gains that can be made
in ^ the use of a different flow rate and/or water quality to ob-
tain the same high quality end product now being obtained.
ARMCO STEEL CORPORATION (ASC)
Using water on an average of 25 times, ASC had drastically
reduced its water usage. As shown in Table 5,(15) a consumption
of 2400 1/min (6240 gpm) amounts to 96% recycling and 6000 to
8000 liters of effluent per tonne of steel,
ASC draws water from the Miami River and, after settling
and holding in ponds, the make-up water is lime-softened and
distributed as shown in Fig. 7, Thirteen separate recirculated
water systems are used. All wastewater flows through a storm
sewer system to Dicks Creek, a small tributary of the Miami
River, During the hot, dry summer months, the natural flow in
the creek dries up, leaving ASC waste as the only water source.
In order to prevent fish kills during the low flow periods, all
wastewater is of sufficient quality to support fish life without
dilution, A simplified diagram of the wastewater system is shown
in, Fig, 3, Seventeen water conservation and wastewater treatment
systems were installed. Typical analyses of discharge to Dicks
Creek at Outfall Nos, 002 (BF and Coke Ovens), 003 (OH), 005
(Primary Mills), and 641 (Pickling) are given in Table 6.
Outfall 003 has high zinc because the open hearth shops use
a large amount of galvanized iron scrap. Also, the significant
fluoride content arises from the use of fluorspar for steelmaking
The primary mill operation is reflected in the significant
level of oil and grease in Outfall 005, The very large chloride
level in Outfall 641 reflects the pickling operation. Outfall
002 is fed by a large volume of non-contact cooling water from
the blast furnace complete, and temperature is a significant
monitoring indicator.
In Figure 9, ' the two modern water systems—one for EOF
and the other for vacuum degassing and continuous casting—are
shown. The entire EOF shop discharges only 190 1/min (50 gpm)
of effluent. Of course, significant evaporation losses occur
at the cooling tower. The original concept was to use boiler
quality water in a totally closed cooling system because the
temperature rise in the hood, duct, and lance cooling is very
high, 60°F. On economic grounds, this concept was changed to
use of lime-softened water and open air cooling towers with ex-
cellent results. The normal blowdown of 95 1/min (25 gpm) re-
sults in five to six cycles of concentration. Dissolved solid
levels reach 1500 mg/1 or higher without noticeable scaling or
corrosion problems.
25
-------
TABLE 5. MILL WATER DISTRIBUTION AND BLOWDOWN,
ARMCO STEEL CORPORATION
Production Area
Coke plant
Blast furnace
Open hearth shop
Basic oxygen shop
Vacuum degas ser
Continuous caster
Soaking pits and
slab furnaces
Hot rolling mill
Picklers 3,
Cold rolling mill
Annealing furnaces
Coating line
Total
*
Make-up ,
1/min
3,800
3,800
4,200
1,100
12,500
(12,500)
1,900
(12,000)
000 (750)
2,600
(1,100)
280
33,000
Total Water Used
Recirculated and
Once Through,
1/min
38,000
87,000
95,000
62,000
12,500
57,000
91,000
265,000
3,800
700,000
1,100
5,300
790,000
Slowdown,
1/min
3,000
2,900
1,100
190
To contin-
uous caster
To hot mill
To hot mill
9,500
3,800
1,900
1,100
110
24,000
Parentheses indicate blowdown from another system.
26
-------
Lime
softening
plant
LPM " liters per minute
3800 LPM
•Coke plant
3800 LPM
Blast furnace
4200 LPM
» Open hearth shop
1100 LPM
• *• Basic oxygen shop
12,500 LPM
•• Vacuum degas
•Concast •
1900 LPM
3.000 LPM
Soaking pits S slab furnaces —Hot rolling -pAnneol
•• Pickling
2600 LPM
280 LPM
-••Cold rolling
*• Coating
-Figure 7. Water supply and distribution
to major production areas
Armco Steel Corporation.
27
-------
3800
3800 <
4200 (
1100
12,500 '
1900
3000
3000
280
.oooj
Coke
plont
,000,
,100}
300)
3,30pJ
soc),
800).
BOO),
w\
Sof
Blast
furnace
Open hearth
shop
Basic oxygen
shop
Vacuum
degosser
NH3 liquor ^j-
L
Cooling water
Gas cleaning r
Cooling water
Gos cleaningj
Cooling water l
Goscleaninar
Hot mill
Dephenoli*olio7]^H3strippmg]-||'2\ ^QQQ
| "|
<
sedimentation |-H_flllZ?lL0l_nl2?0] imn
I
*ii>difnf Motion t x •» Ir ' _7 ^
QC to onj
f~ — — * — • —i
^ Continuous ^ sedimentation 1-1
i cosTcr i w— ••*_ MV — — . *j i
,._ j |
(2,sooi q^on
Chemical coagulation' , :— J-f3oHvl .,«-.
~1 8 sedimentation > *L An«£Linl IP22^ 1 1 00
Dij*kl»re
^ 1
Acid rinse
Pnld mill
8 emulsions
• Cnot'tno
_, . rrom
lened water M!-m;
Deep well disposolj
J"Acid"neut , /. ..-{ ,-7on
-t-j iron 8 oil| in V'j, ji( J/uu
i_retno«olj
' (3°j 1 1 0
"I
thru nirkc; Pr^eU (6240) 24.000
33,000 (8775)
1/min (gpm)
River
Figure 8. Simplified schematic of the wastewater
system, Armco Steel Corporation.(15T
28
-------
TABLE 6. AVERAGE ANALYSIS OF EFFLUENTS TO DICKS CREEK,
ARMCO STEEL CORPORATIONM_
PERIOD 10/1/77 TO 10/31/77(15)
Analysis at Otttfall No.
Parameter 002 003 005 641
TSS, mg/1 - 38.6 17 2
Total iron, mg/1 - - - 0.222
Dissolved iron, mg/1 - 0.032 0.05 0.105
Fluorides, mg/1 - 16.9
Chlorides, mg/1 -„...- - 541
Total zinc, mg/1, .... : s ...-..,- 55 0.053 0.077
Lead, mg/1 - 0.427
Oil and grease, mg/1 - - 4.5
pH 7.9 7.56 8.45 8.2.
Flow, 106 liters/day 3o8 3.3 2,5 8,7
Temperature, °C (°F) 21 (70) -
29
-------
Hood a
duct
680,000
(18,000)
Evaporation
23,000
(6,000) Slowdown
Moke-up water
7
Oxyge
loncp
(4)
\
n
r
p
fa
spr
'•
"
Pump 8
fan seals
sprays, etc.
woter
Cooling woter system
HT
T<
\\ \
lickenersj
) filters
Make-up
Filters
a vacuum
pumps
water ,
'*
Tose
1^71
fine rlonnino water S»
190
17,000
(4'50(*
Evaporation
vt/
Gas
cleaning
system
(a)
Softened make-up water
12.500 t
Vacuum
degosser
condenser
cooling
Deep bed
filters
Continuous
caster
slab
cooling
1900
500)
Soaking pit 8
Slab furnace
cooling
Slab 8
hot strip mill
clarification
plant
Pickers
r
To Dicks Creek
(b)
Annealing
furnace
cooling
1/mfn (gpm)
Figure 9. Steel melt shop water system, Armco Steel Corporation
(a) EOF is .served by two separate water systems discharging on'lv
190 1/min (50 gpm) . (b) Vacuum degassing and continuous castin'o-
waters are reused. •L"S
30
-------
From this it is realised that process water at the EOF shop
can tolerate a high TDS level. How high this level can attain—
with proper chemical treatment to prevent scaling—can only be
determined after a sustained operation at different high levels.
Obviously> the plant operators will be unwilling to take such
risks to determine the limit of equipment/chemical capabilities
in controlling scaling problems just to determine the water qual-
ity limitations for, any piece of equipment, though this informa-
tion may enable them to further reduce discharges.
Figure 9b shows how the very large volume of water required
for vacuum degasser and continuous casting units are reused in
the primary mills,
A perennial problem is treatment of spent pickle liquor.
At ASC, at the terminal waste treatment plant, the spent pickle
liquor is disposed of'by deep oil injection. All other acid and
oily wastes are combined and treated. The oily mill scale sludge
also causes blue haze when burned (as at KSC) and is dumped at
presento It:is expected that after several years of exposure
it may be usable in the sinter plant„
Very little specific data; on water quality and quality-
related product problems were available at ASC, The familiar
problem of speck rust and carbon spots on flat products (men-
tioned at KSG) are also evident at ASC. Unlike KSC, at ASC they
feel that speck fust is due to high dissolved solids (chlorides)
in the water. They .are studying this problem by changing from
river water (TDS 70 to 220 mg/1) to well water (<30 mg/1). They
are working on temperature/humidity control, and increase in
oiling of pickled sheets.
COLORADO FUEL & IRON STEEL CORPORATION (CFI)
This 100-year-old plant is established in a semi-arid re-
gion at Pueblo, Colorado, where water rights are very precious
and more people were killed for Stealing water than for stealing
horses I The plant waiter is taken from th$ Arkansas River 40 km
(25 miles) west of Pueblo, It is conducted by a 74 km (46 mile)
long canal to large storage reservoirs located about 7 km (4
miles) from the plant. The transportation cau$es 15% loss of
water taken from the river. Thus, out of a typical 330 x 106
I/day (87 MGD) water taken out of the fiver, about 280 x 10s
I/day (75 MGD) is received at the reservoirs, as shown in Fig. 10.
The effluent is discharged into Salt Creek, a natural flow
channel lying almost entirely within CFI property. Typically,
about 197,000 1/min (52,000 gpm) of water is discharged. In
other words, the entire 280 x lO6 I/day (75 HGD) taken in is dis-
charged though some local recyling of water is carried out. On
an average, water amounting to 71,000 I/tonne (17,000 gal/ton)
of steel is used for a production level of 1,45 million tonnes/
31
-------
ggj ~r!'7 j
I jf. „_£. __L. nn
Figure 10. Mill water distribution, Colorado Fuel & Iron, 1974
32
-------
year. The Arkansas river becomes totally dry after the entire
river flow has been intercepted by the city, CFI, and other
owners„ The river becomes a river again below Pueblo, com-
posed entirely of the sewage outfall of the community and the
steel millc Thus, the situation at CFI is different from other
steel plants. The 280 X 106 I/day (75MGD) intercepted by CFI is
returned fully so that downstream there will exist a river for
others to tap. The quality of the returned water, however, is
extremely important, and CFI ensures that it is of high quality
with fish thriving in the holding lagoons.
Analysis of plant influent for 1976 is given in Table 7
(data provided by CFI)„ Certain special features of this analy-
sis may be noted,, This area of Colorado has many mineral depos-
its and the high lead and associated arsenic, as well as fluor-
ides, reflect that condition, '
The October 1977 average, maximum, and minimum analyses of
plant effluent are given,in Table 8, Again, the high level of
lead and zinc may be noted. The quality criteria (I6' for water
indicate that cyanide, phenol, and mercury are in excess. The
source of mercury may be from the coal washery, CFI is one of a
few steel plants which have a coal washery within the plant
boundary, and large lagoons have been established to settle the
coal fines.
No information was available regarding effect of water
quality on product quality. The simplified material flow dia-
gram in Fig, 11 shows the nature of end products (no cold rolled
sheet or coated products), and these arevirtually not affected
by water quality,
DISCUSSIONS WITH GROUPS AND INDIVIDUALS
In this category, the following activities may be listed:
1, Discussion with AISI Environmental Committee
2, Discussion at Hydrotechnic Corporation
3, Discussion with Mr, Walter Zabban, The Chester
Engineers, Pittsburgh, Consultant
American Iron and Steel Institute (AISI)
AISI is a trade association for the steel industry and is
located in Washington, D.C, At the beginning of this study a
meeting was arranged with Mr, W, Benzer, who is in charge of the
AISI Environmental Committee, In this meeting, Mr, Benzer was
helpful and gave copies of several studies sponsored by AISI on
Pollution Control in the Steel Industry,
33
-------
TABLE 7. ANALYSIS OF PLANT INFLUENT (1976),
COLORADO FUEL & IRON
Parameter
Alkalinity, mg/1
Ammonia (N) , mg/1
Nitrate (N) , mg/1
Chloride, mg/1
Sulfate, mg/1
Dissolved solids, mg/1
Suspended solids, mg/1
Oil and grease, mg/1
Arsenic, yg/1
Copper, yg/1
Fluoride, yg/1
Iron (dissolved), yg/1
Lead, yg/1
High
129
0.46
0.1
12
181
313 ,
23.9
3
20
40
680
480
30
Analysis
Low
50
<0.1
0.1
<1
82
226
4.38
<1
<5
<5
410
10
<10
Average
100
0.1
0.1
6.8
105
270
13.4
2.3
9.6
5.7
53
143
18
34
-------
TABLE 8.
ANALYSIS OF PLANT EFFLUENT FOR OCTOBER 1977
COLORADO FUEL & IRON
Parameter
Temperature, °C
Dissolved oxygen, mg/1
BOD5, mg/1
pH
TSS, mg/1
Oil and grease, mg/1
Ammonia (N) , mg/1
Cyanide, mg/1
Chloride, mg/1
Sulfate, mg/1
Arsenic, yg/1
Iron (dissolved) , yg/1
Lead, yg/1
Zinc, yg/1
Phenol, yg/1
Mercury, yg/1
Min
18
3.5
2.9
7.7
5
1
1.4
0.044
-
-
-
<20
<40
60
<3
Analysis
Max
23
5.6
6,1
8.4
14
10
3.6
0,222
18
185
<0.1
30
40
350
57
<0.4
Average
4.9
4.2
«•*
8
3
2.0
0,110
-
-
-
30
<40
220
7
Quality
Criteria^16'
0.005
50
50
5000
1
2*
0.05 and 0.1 yg/1 for fresh water aquatic life and wildlife and
for marine aquatic life, respectively.
35
-------
SCRAP 2150
HOME + PURCHASE
BASIC
OXYGEN FCE.
(BOF)
CAST IRON
PIGS FOR O.H.
FD.RY 86
2
ELECTRIi
\ FURNACES J
^^ _L*S
INGOT MOLDS
93
**1
STEEL INGOTS
3730
1 ^^V S*^ ^^^^^
CONT. CASTER
270
IBLOOMS& BILLETS
ROUNDS S RAILS
3090
R.R.
SPIKES
I—wTRET
WIRE PRODUCTS
GRINDING
BALLS
IG
GRADER
BLADES
TIE pJrf
RAIL ANCH,
MERCHANT
BAR
STRUCTURALS
SEAMLESS TUBE
GRINDING
BARS
FLATS & MISC
RAILS
Figure 11. Simplified material flow diagram, Colorado Fuel & Iron
Pueblo plant. Average daily (365 days) tonn.es in 1971.
36
-------
A couple of months later, a meeting with the full AISI
Environmental Committee took place where the EPA Project Officer,
Mr. Ruppersberger, was also present„
While trying to be helpful, AISI did not agree to refer our
requests for information to any steel plant. They felt that
enough information had already been supplied to EPA and that this
should be sufficient and utilized. Any steel plant approach to
be made by IITRI on this program had to be strictly on an indi-
vidual basis.
Drc S0 C0 Caruso, of the Mellon Institute, Carnegie Mellon
University (CMU) was present at the meeting; CMU has been asso-
ciated with AISI for many years on conducting studies on pollu-
tion, and at our request AiSI.. agreed to release several volumes
of studies completed so far,^ '' ^Q) These studies do not
directly relate to this task.,
; -.
Hydrotechnic Corporation. New York
Hydrotechnic (HC) is, at present, involved in a study for
EPA. The study is entitled "Integrated Steel Plant Pollution
Study for Zero Water and Minimum Air Discharge„" A visit was
made to their office,
HC is studying water discharges from the following
integrated steel plants:
1. Kaiser Steel, Fontana (KSC)
2. Youngstown Sheet & Tube, Indiana Harbor (YSTIH)
3c Inland Steel, Indiana Harbor (ISIH)
40 United States Steel, Fairfield (USSF)
5, National Steel, Weirton (NSW)
The thrust of HC's study is on zero-discharge, For this,
HC is compiling accurate information on flow rates, evaporation
losses, and recycling. They are marginally concerned with water
quality, and very few data were available from them.
The KSC water quality data shown earlier in Table 4 were
from the Hydrotechnic study: Tables 9 to 11 give the data avail-
able from Hydrotechnic on the three other steel plants. The data
are very meager and show that only a few types of water qualities
are used in these plants. No information was available from
these steel plants through HC on the effect of minimum water
quality on product quality.
37
-------
TABLE 9. WATER ANALYSIS, NATIONAL STEEL CORPORATION, WEIRTON
00
Quality
Water Use
Non-contact cooling
Runout table sprays
on hot strip mill
Cold rolling mills
Pickle lines and
other facilities
TSS TDS
37
Hardness
(A1203)
Alkalinity
(Methyl
orange)
Total
Alkalinity,
(CaC03)
2
3
Plating lines
Boiler house
<1 2250
34.2
47.9
50-100
For Quality 1: Na = 20 mg/1, phenol = 15 Tig/1, CN~ = 37 rpg/1, BOD =3.0,
ammonia (N) = 800 Vg/1, nitrates =0.7 mg/1, sulfates = 78 mg/1
For Quality 3: Silica = 25 mg/1.
All other data are in mg/1,,
-------
TABLE 10. WATER ANALYSIS, U.S. STEEL FAIRFIELD WORKS, ALABAMA
Water Use
Runout table sprays
and pickle liquor
dilution water
Non-contact cooling,
cold rolling mills,
plating lines,
pickle liquor rinse
water, and other
facilities
Analysis, mg/1
Oil andChlo-
TDS TSS Grease
rides
Sul-
fates
175
175
25
25
10
10
15
30
39
-------
TABLE 11. WATER ANALYSIS, YOUNGSTOWN SHEET & TUBE,
INDIANA HARBOR
Item
(All in mg/1
except pH)
pH
TDS
TSS
Oil and grease
Chloride
Sulfate
Phenol
NH4 (total)
CN (total)
Zinc
Cr (total)
Lead
Iron (dissolved)
Iron (total)
Hardness (total Ca)
as CaCO-
Alkalinity as CaC03
Hot Rolling Mills,
Strip Cooling,
Pickle Dilution
and Rinse
6.2-9.0
450
40
21
61
143
0.03
3.5
0.11
0.20
0.04
0.06
0.63
11.4
Cold
Rolling
Mills
7.0-11.4
565
14
7
25
254
<0.01
0.10
0.12
0.30
<0.01
0.03
0.26
1.30
Non- Con tact
Cool ing t
300
10
100-150
0-90
t
Worst quality that can be tolerated.
Should -not exceed Langelien Index for scaling potential.
Values in table are preferred by plant. However, plant uses
intake water on a once-through basis.
40
-------
Discussion with Walter Zabban
Mr. Zabban, Chief Engineer, The Chester Engineers is a
very knowledgeable person on water quality in thTs?eeI' industry
He was visited several times. His knowledge on various wate? *
treatments was very helpful to 'other tasks? On this tLk
he could only provide general guidelines regarding the effect of
»aHt.1 10 be enc°™tered in equipment . mainten-
ance and the best available treatment to improve water quality.
INFORMATION FROM EQUIPMENT AND WATER CHEMICAL SUPPLIERS
The few equipment manufacturers who responded to our in-
quiries have the following two general observations to make:
1. The equipment is rugged in design and can
accept a wide range of water quality with
modifications made by suitable chemicals,
where needed.
2. The equipment is made to customers' water
specifications .
A response from Koppers Engineering and Construction, a
major coke oven and by-products plant supplier, was also -
obtained. Without specifying any quantitative data, the gen-
eral philosophy of water -quality was mentioned - soft water, low
chloride, temperature limitations, low suspended solid content;
and adequate Slowdown for scale control.
Morgan Construction Co., a supplier of rolling mills, states
that they do not issue any rigid water specification but a guide-
line. For example, pH to be 7.0, chloride <100 mg/1, sulfates
<300 mg/1, TSS <25 mg/1, and largest suspended particle to be
less than 250 ym (0.010 in.).
Loftus Engineering Corporation, an engineering and construc-
tion firm, replied to the effect that they seldom had an oppor-
tunity to specify water quality for their clients because avail-
able water had to be used. Cooling water temperature is limited
to 32°C (90°F). Due to the size of equipment, large suspended
particles are acceptable; and in the event of scaling, sediment,
or fouling occurring, the client takes the necessary steps to
alleviate the problem.
Continuous casting mold cooling water requirements have
been critically analyzed in the literature because even a trace
of scaling inside the mold may change the heat transfer coef-
ficient significantly, resulting in a serious molten steel break-
out from the thin enclosing solidified shell. Some of the
various deposits encountered in a continuous casting mold are
shown in Table 12. "9> With proper zeolite softener operation,
41
-------
(19)
TABLE 12. MOLD DEPOSITS IN CONTINUOUS STEEL CASTING ^ '
Analysis, %
Deposit Case I' Case IICase III
Silica as SiOn 414
Iron as ^e,2°3 1 85 8
Loss on ignition 7 9 29
Phosphate as P205 7 - 28
Calcium as CaO 48 - 16
Magnesium as MgO 2 - 7
Carbonate as C02 31 -
Zinc as ZnO -
Chromate as Cr000 - 5 4
Case I - Calcium carbonate scale; poor softener
operation (closed system)
Case II - Migratory corrosion products (closed system)
Case III - Severe hydraulic fluid leaks (open recircu- ;
lating tower system)
42
-------
and changing from re circulating tower system to a closed loop
operation, infiltration of the system by oil, grease, hydraulic
oil, and suspended solids is prevented. Closing the system also
minimizes inhibitor consumption, Chromate-type inhibitors are
recommended, but nitrates can be used. Phosphate and zinc-bear-
ing inhibitors are to be avoided since either will rapidly plate
out on mold surfaces and cause breakouts.
In continuous casting, the spray water system is often the
dirtiest and—combined with airborne contamination, corrosion,
and fouling, normally associated with open air cooling tower
systems--presents possible problems as shown in Table 13, With
proper design of the water system, all the problems can be total-
ly overcomec ,
FOREIGN STEEL PLANTS
Hoesch iron and steelworks located on the eastern fringe of
the Ruhr district in West Germany has installed modern water re-
circulation systems for its 1727 mm (68 in.) hot strip mill. As
a result, the system requires only 1.100 liters (290 gallons) of
make-up water per tonne of steel produced,, (20)
The Hoesch water systems (as shown in Fig0 12) are designed
for reuse at various facilities. The quality of wastewater is
restricted to that involved in the sludging operation and by
faults in the individual systems.
Long-term analyses have shown that cost of recirculated
water is substantially lower compared with nonrecirculating
systems, in spite of additional depreciation and maintenance
costs. The total installed pump rating is about 20,000 kw.
Their investigation has also shown that investment cost of
sea water cooling systems in new plants located directly on the
North Sea is considerably higher than that of their system.
After a thorough comparative analysis of capital costs,^
maintenance and operational problems of evaporation cooling with
steam generation, and cooling tower system, Hoesch opted for
evaporation cooling. Evaporation cooling system offers economic
advantages under the following basic conditions:
1. The large volume of steam generated must be
accepted by the existing steam mains and used
in the blast furnace area or power-generating
station.
2. Where fuel costs are high and investment costs
are low, the evaporation system is definitely
advantageous.
43
-------
TABLE 13. CONTINUOUS STEEL CASTING PROBLEMS
(19)
Problem Area
Migratory corrosion
products
Scale and suspended
solids
Oil
Solutions
Effective corrosion inhibitor program
Use of stainless steel spray headers
Improved scale pit & filter plant operation
Use of polymeric/phosphonate dispersants
Effective use of oil skimmers & filters
Use of surfactants
Improved housekeeping--minimize hydraulic
fluid and oil leaks
Biological fouling Effective use of proprietary biocides
Miscellaneous
foreign debris
Improved housekeeping practices
Consistent operation of filter equipment
44
-------
01
Recirculating system
for pusher furnaces
Recirculating system roughing
and finishing mills, coders
Run-out roller table
Recirculating system
2100
Recirculating system
electricals
1/min
Figure 12. Strip mill cooling water recirculation systems,
Hoesch Hiittenwerke, Dortmund, West Germany. C20'
-------
In addition to paying water cost for drinking water, Hoesch
had to pay a wastewater fee of DM Qo 21/1000 liters, i.e, about
$0.40/1000 gallons o With the newly installed recirculation sys-
tem, the water cost was reduced to DM 0,10/1000 liters or $0.19/
1000 gallons .
The permissible degree of rolling mill contamination is
given in Table 14n On the basis of 1210 liters/tonne (290 gal-
lons/ton) of hot strip, the third column in Table 14 shows the
ppm values as g/tome and compares with the fourth and fifth col-
umns which are, respectively, the BPCTCA (1977) and BATEA (1984)
effluent guideline data. Hoesch' s permissible values are better
than 1984 guideline data.
In the USINOR's Dunkirk plant in France, for an output
of 6000 tonnes/day (2 million tonnes/year) a makeup wa^ter of 0,9
to 1.0 million liters/hr is needed, which is equivalent to
3600 to 4000 liters/tonne of steel. As mentioned earlier, at the
8 million tonne/year stage the water requirement will be almost
half of 4000 liters/ tonne. •
At the Dunkirk plant, the fresh water coming from Dourbourg
Canal is decanted, heated with ferric chloride, softened with
lime, filtered, and chlorinated. Some water is further softened
by ion exchange. Table 15 gives the individual unit requirements.
With 98.5% recycling, the ARBED^22^ plant water (Luxemburg)
requires 2500 liters/ tonne (2.5 m3/ton) of steel; 53?0 is used in
the blast furnaces, 327o in the steel plants and rolling mills ^
and 15% in the power station and for miscellaneous uses.
Four separate water circuits are used: one for BF and sin-
ter plant, second for BF gas cleaning, third for power station,
and fourth for mills and other uses.
;'•
RECYCLING OF STEEL PLANT WASTES
AND ITS RELATIONSHIP TO WATER USAGE
There is mounting pressure as well as. increasing interest
in the recycling of every unit of iron-bearing material gener-
ated within the plant perimeter. This waste recycling is re-
lated to water recycling, both physically and technologically.
At the many plants of the British Steel Corporation, C23j about
2.4 millipn tonnes of waste was estimated to arise in 1975, as
shown in Table 16. This quantity amounts to about 1070 of raw
steel production.
The properties of collected waste must fit the units that
will consume it. These properties depend on (1) form of collec-
tion, (2) the particle size distribution, and (3) the chemical
analysis.
46
-------
TABLE 14. PERMISSIBLE IMPURITIES IN INDUSTRIAL WASTEWATE'R FROM ROLLING MILLS,
HOESCH IRON & STEEL WORKS, DORTMUND, WEST GERMANY(20)
Item
Temperature
pH
Settling materials (TSS)
Total chromium
Copper
Nickel
Zinc
Cyanides
Oil streaks
Oil and grease
(petroleum ether extraction)
Total iron
Permissible
Dortm
ppm
30 °C (86°F)
6.5-9.5
1.0
4.0
3.0
5.0
5.0
1.0
0
5.0
No limit
EPA Guideline
n,i«nt-w Hot Forming Flat, , ,
quality, category "0" - Hot Strip T
ana BPrTCA
g/tonne1" (1977)
6.0-9.0
1.0 1.1461
4.0
3.0
5.0
5.0
1.0
0
5.0 0.3438
3ATEA
(1984)
6.0-9.0
0.0156
0.0063
Except temperature and pH. 1 ppm = 1 g/tonne.
on 1,200 liters/tonne (290 gallons of effluent/ton) of steel.
-------
TABLE 15, UNIT REQUIREMENT? FOR WATER, USINOR,
DUNKIRK, FRANCE (21)
Process Unit
Blast furnaces
Cooling
Filtering of the gases
Steel works
Cooling of the hoses
Cooling of the smokes
Scrubbing of the gases
Rolling mills
Cooling of the motors
Rollers (stabling and
quarto)
Descaling
Strip rolling train
Cooling of the motors
Train, furnaces, and
descaling
Total
Water Need,
1000 I/hr
4,000
3,600
200
100
1,500
1,100
1,550
450
3,000
2,000
25,000
Cooling Towers
1 cooler of 4 x 106l/hr
1 cooler of 4 x 106l/hr
1 cooler of 1.5 x 10?l/hr
1 cooler
1 cooler
1 cooler
1 cooler
48
-------
TABLE 16. SOURCES AND RATES'OF PRODUCTION OF IRON-BEARING WASTES,
BRITISH STEEL CORPORATION (BSC), 1975<23)
Source
Sinter plant dust
Blast, furnace dust (dry
Blast furnace dust (wet)
Baste oxygen steel fume
Electric arc furnace fume
Slag metal recovery:
Ironmaking
Steelmaking
Mill scale
Pickling acid residues
Normal Rates
of 'Production'
(dry basis) _
20-40 kg/tonne .sinter
10-10 kg-/tonne hot metal
10-20 kg/tonne hot metal
7-15 kg/tonne steel
10-20 kg/tonne steel
kg /tonne hot metal
kg/tonne steel
20-60 kg /tonne steel
5-10 kg/tonne steel
Estimated Quantities
Arising within. BSC
in 1975, tonnes
300,000
200,000
180,000
180,000
40,000
150,000
380,000
930,000
30,000
-------
The form of collection is intimately associated with_water
treatment and recycling facilities of the plant. The initial
water content of the wastes is normally either very low (<5%) or
very high (>90%) . Some wastes are collected dry, others by wet
scrubbing. Reduction of >90% to 70% water is usually carried out
in thickeners, and the underflow is either allowed to settle and
dry (requiring large land areas and, being at the mercy of the
weather, is not preferred) or filtered to a cake containing 15
to 30% moisture. The technology is available and can be coupled
to water recycling solutions.
Particle size in the wastes varies widely between processes,
as shown in Fig. 13. Also, it depends on collection technique,
dry vs. wet, and is thus related to water recycling,, Apart from
the coarse mill scales, none can be recycled directly. The
wastes cited in Fig. 13 do not include iron-units that are as-
sociated with waste pickle liquor generation and recycling.
Chemical analyses of the wastes, particularly their tramp
element contents, may pose problems to their recycling and in-
directly affect water recycling„ The wastes usually have the
following groups of metals and minerals:
1. Valuable reusable materials (Fe, Mn, C)
2. Slag/gangue materials (CaO, Si02, A1203, MgO)
3. Tramp elements (Zn, Pb, S, P, K20, Na20, Ni,
Cu, Sn, Mo)
If chromium plating is used, then Cr-bearing residues will
also be generated.
At BSC, sinter plant dust, as well as BF and EOF dusts col-
lected dry, is recycled. The wet collected dusts are dumped,
thus wasting valuable water. None of the electric furnace dust,
containing high levels of tramp elements, is recycled. Mill
scale and slag metallics are recycled. At BSC, out of 204
million tonnes of waste., 1.8 million tonnes are recycled.
The study at BSC shows that a complete waste recycling sys-
tem must be a part of complete water recycling, and a synergistic
solution is best for both.
SOME STRIP QUALITY PROBLEMS
ASSOCIATED WITH WATER QUALITY
From the foregoing discussion it is clear that very little
is known about minimum water quality requirements for each unit
steel-making process. Even much less than that is known about
the effect of water quality on product quality. The problems of
"speck rust" of plates and sheets, and "blue haze" due to sinter
plant use of oily mill scale residue were mentioned earlier.
Another problem that has come out in the open is strip cleanli-
ness, and corrosion problems of auto body sheets associated with
it.
50
-------
100
—* 90
0)
If 80
(0
O
« 70
"""' 60
•M
.c
50
.0
30
TO
"3 20
3
O 10
Blast furnace
.dust (wet)
Electric arc
furnace fume
Basic oxygen
steel fume
\
\
Sinter plant dust
Mill scale
Blast furnace dust (dry)
"V
v..
1X3
2.5
10 25 50 100 250 500 1000 2500 5000 10000 25000
Particle Size (microns) [log scale]
Figure 13. Particle size distribution for representative samples
of ferruginous wastes.(23;
-------
In a recent article, (24) Q^J researchers have speculated
that the organic carbon deposits on steel sheets may arise from
residues of drawing oi!0 These residues are remnants of water-
oil emulsion used for temper rolling,,
In a recent panel discussion on strip cleanliness at the
Joint AISE/ASLE Lubrication Session at Cleveland, certain similar
problems were discussed,, The discussion was off-the-record.
The nature of oil-burn on steel surface^ which appears in
cold rolling was related to fatty oil and water on the surface
resulting in formation of iron oxide.(25)
52
-------
SECTION 7
REUSE AND RECYCLING OF WATER
IN THE IRON AND STEEL INDUSTRY
,The assumption that fresh water is an inherently cheap
commodity, abundantly available without effort, was finally laid
to rest in the 1970's. Almost 90% of water utilized in the steel
industry is n on consumptive in nature, i.e., the steel mills re-
turn them directly to the lakes, rivers, and other water bodies
from which they were taken. Of the remaining 10%, 80% of it
goes back to the environment in evaporation and returns promptly
through rain and snow0 Only about ,2% may be said to be consumed,
i.e., lost with sludge and other waste products and only re-
cycled back to water bodies after prolonged periods„ However,
that 2% amounts to some 4200 I/tonne (1000 gallons/ton) steel,
and a steel production ,of 136 million tonnes/year (150 million
tons/year) means an immediate loss of 570 billion liters (150
billion gallons) of water/year;or about 1560 million liters/day
(400 million gallons/day). One means of conserving these sup-
plies ,is by the. reuse of water. --It is necessary to define the
terms reuse and recycling a little more precisely before an
evaluation can be made.
Reuse denotes that water is used and returned to a :water
body for subsequent use by another consumer. If the water body
happens £p be the sea, then a direct loss of resource will ,occur,
Recycling implies repeated use of water for the same or
successive processes,,
The concept of total recycling and zerp-discharge must
take into consideration:
lo Transfer of pollutant to air, and its control.
2^ Solid waste as a pollutant and its recycling.
At presenti the future EPA guidelines stipulate a rate of
effluent discharge coupled-with pollution level. Several S-teel
plants in the USA and abroad are, at present, doing better "than
90% recycling and some as high as 98% recycling. On the other
hand, some plants may be using water on a virtually once-through
basis, though the discharge is treated to meet state and federal
regulations. An example is Colorado Fuel and Iron, which draws
53
-------
about 280 x 10s liters/day (75 MGD) and discharges the same
amount. With significant recycling, the withdrawal can be
considerably lessened, but the amount withdrawn (less evapora-
tion losses) must be returned to the Arkansas River to enable
downstream users to have adequate water„
Figure 14 gives a simplified picture of a typical recycle
system. (*•") Contaminants as suspended or dissolved materials
are picked up at a "consuming" point. Water is "lost" from the
system due to direct losses, evaporation, or with impurities
(sludges) at the treatment stage.
Relationships can be obtained based on water and contam-
ination balances, with the term definitions given in Fig. 14,
such as: '
A = B + L (1)
B = Y + CL - D
R - C (2)
R = AC + Y - D _ AC + Y - D
g A - L (3)
The basic concept of water conservation by recycling is
that (A + V) vpl/hr of water can be made available with a make-up
supply of A vol/hr. A will be minimized by reducing losses L
and by reducing B, the blowdown. B may be reduced, as Eq0 2
shows, by (1) minimizing contamination (Y), (2) maximizing con-
tamination removal (D) by treatment, and (3) operating at the
maximum permissible recycle concentration in terms of the total
contaminants. It is Eqe 3 that was spught in this task.
That is, we were trying to obtain information on water contam-
ination level with which the equipment can operate efficiently
and still produce the quality of products demanded of them.
A simple fact of Eq. 2 is that as R approaches C from the
high side, B increases significantly. In other words, B can be
made a very small value if R is made significantly much larger
than C. However, assuming C to be the level of pollution pres-
ent in water obtained from an acceptable body of water, an R
much larger than C cannot be tolerated, or R has to be treated
again to bring it down to C level.
Quantitatively, it is doubtful if recycling has much ef-
fect on water consumption except that it might be argued that
it could lead to overall increases in losses by evaporation.
For example, in an open-air cooling system the actual water
loss is greater if a proportion of the wate** is evaporated to
provide cooling than if the water is used on a once-through
basis—that is, where the sensible heat of the water is in-
creased but no diminution of quantity occurs» Thus, one has
to consider closed evaporation cooling systems instead of open-
air type, if real saving in water is to be accomplished in re*-
peated and total recycling.
54
-------
MAKErttP WATER -—
A l/hr (gal/hr)
. C kg/I (Ib/gal)
WATER USE
CONTAMINANT ADDITION
Y kg/hr (Ib/hr)
A + V l/hr (gal/hr)
Cone.
YR-0>AC
A.V
kg/1 (Ib/gal)
RECYCLED V/ATER
V . l/hr (gal/hr)
. lill kg/1 (Ib/gal)
TREATMENT
REHQVAL OF
CQHUM HUNTS
D kg/hr (Ib/hr)
Including losses
WATER LOSSES
[Evaporation and others]
'L l/hr (gal/hr)
SLOWDOWN EFFLUENT
B ]/hr (gal/hr)
ConC. R kg/1 (Ib/gal)
Figure 14- Simplified; flow sheet for recycling.
(26)
55
-------
REFERENCES
1. American Iron and Steel Institute, Annual Statistical Report,
1976. Washington, D0Co, 1977.
2. Arthur D, Little for the American Iron and Steel Institute,
"Steel and the Environment: A Cost Impact Analysis, No.
C-76482, May 1975.
3. National Materials Advisory Board, "Trends in the Use of
Ferroalloys by the Steel Industry of the United States,"
NMAB 276, Washington, D.C., July 1971.
4. William Y. Mo and Kung-Lee Wang, "A Quantitative Economic
Analysis and Long-Run Projections of the Demand for Steel
Mill Products," 1C 8451, Bureau of Mines, Washington, D.C.,
1970.
5o National Journal, Jan. 14, 1978, p. 55.
6«, H. E. McGannon (ed.), The Making. Shaping and Treating of
Steel, 9th edition, 1971, U.S. Steel Corporation, Pittsburgh,
Jfenn0
7. G. W0 Cook, "Conservation of Water by Reuse at the Appleby-
Frodingham Steelworks, Scunthorpe," Iron and Steel Inter-
national, Vol. 47, October 1974, p. 393.
8. A. Wagner, "Experience Gained in the Iron and Steel Works of
Luxemburg by Using Closed Water Circuits and the Effect of
These Measures on the Economy and Water Pollution," Iron
and Steel International, Vol. 47, No. 3, June 1974, p. 235.
9. Mo Huysman, "Reduction in the Amount of Water Used in
USINOR's Dunkirk Plant," ibid., p. 236.
10. U.S. Environmental Protection Agency, "Development Document
for Proposed Effluent Limitation Guidelines and New Source
Performance Standards for the Steel Making Segment of the
Iron and Steel Manufacturing Point Source Category,"
Washington, D.C., January 1974.
11. U.S. Environmental Protection Agency, "Development Document
for Advanced Notice of Proposed Rule Making for Effluent
Limitation Guidelines and New Source Performance Standards
for the Hot Forming and Cold Finishing Segment of the Iron
and Steel Manufacturing Point Source Category," EPA-440/1-
75/048, Group I, Phase II, Washington, D9C., August 1975.
56 .
-------
12. U.S. Environmental Protection Agency, "Development Docu-
ment for Interim Final Effluent Limitation Guidelines and
proposed New Source Performance Standards for the Forming
Finishing and Specialty Steel Segments of the Iron and
Steel Manufacturing.Point Source Category," Vols. I and
II, EPA-440/l-76/048-b, Group I, Phase II, Washington,
D.Co, March 1976.
13c Hootie Rugge, Kaiser Steel Corporation, "Kaiser Steel Water
Use and Reuse," July 21, 1976, private communication,,
14, Robert D. Wight, "How It's Done at Kaiser," The Bulletin,
Vol. 8, No. 4, 1972, p. 15,
15 o J. Thompson, "Water Pollution Control Program at Armco's
Middletown Works," Iron and Steel Engineer, Vol. 49, No., 8,
August 1972, p. 43o
16o U.S0 Environmental Protection Agency, "Quality Criteria
for Water," EPA-440/76/023, Washington, D0C,, July 1976.
17. G, Mo Wong-Chong and S. G0 Caruso, "An Evaluation of the
Treatment and Control Technology Recommended for the Blast
Furnace (Iron) Wastewater," Mellon Institute, Carnegie-
Mellon University, Pittsburgh, Penn,, August 1976.
18o G. M. Wong-Chong, S0 G0 Caruso, and T. G0 Patarlis, "An
Evaluation of EPA Recommended Technology for the Treatment
and Control of Wastewater from the By-Product Coke Plants-
Alternate 2," Mellon Institute, Carnegie-Mellon University,
Pittsburgh, Penn.
19„ D. J0 Juvan, "Design of Critical Water System for Contin-
uous Casters," Tech. Paper No. 247, presented to 1975
AIME National Open Hearth and Basic Oxygen Steel Confer-
ence, Toronto, Canada, April 13-16, 19750
20, H. F. Thee gar ten and R0 K. von Hartman, "Hoesch Hutten-
werke's Hot Strip Mill Water Supply System," Iron and
Steel Engineer, Vol. 50, No, 8, August 1973, p. 67.
21. P0 Guyard, Tribune de Cebedeau, No, 255, 1965, pp. 58-74.
22. P. Mosel, Revue Technique Luxembourgeoise, No. 3, 1954,
pp0 138-163.
23o N0 Y. West, "Recycling Ferruginous Wastes: Practice and
Trends," Iron and Steel International, Vol» 49, No. 3,
June 1976, p. 173.
24, Curt Hazlett, "GM Probe May Solve Rust Riddle," American
Metal Market/Metalworking News, Vol. 85, No. 234, Dec. 5,
1977, po 12.
57
-------
25. Y. Tamai and M. Sumitomo, "Qn the Nature of Oil-Burn on
Steel Surfaces," J, Amer. Spc. Lubric. Eng., Vol. 31,
No. 2, 1975, p. 81.
26. D. G. Miller and D0 H. Newsome, "Conservation of Water by
Reuse in the United Kingdom," Chemipal Engineering Pro-
gress Symposium Series, Vol. 63, No. 78, 1967, p. 13,
27. Anon., Iron & Steel Engineer, Vol. 54, No. 7, July 1977,
p. 63.
58
-------
APPENDIX A
STATISTICAL HIGHLIGHTS OF THE U.S. IRON AND STEEL INDUSTRY<27-*
ponniiPTinw
f (Mi II !**•%• fit ™
twtiMont of
nrt Tom}
SHIPMENTS
(millions of
net tons)
SHIPMENTS
MAJOR
PRODUCTS
ALL GRADES
(millions of
net tons)
SHIPMENTS
MAJOR
MARKETS
(millions of
net tons)
EMPLOYMENT
FINANCIAL
CAPITAL EXPEND'S
FOR AIR & WATER
QUALITY CONTROL
HBMMMMBMWf^mBVia^MMMBWBMBHBB
FOREIGN
TRADE
Ifniliions of
Tbtil US. Pin Iron
Tout US. RawStMl
1 Open Hnrth
Basic Oxygen
Elactric
Total Canadian Raw Steel
Total World Raw Steel
Total Steel Mill Product*
Carbon
Alloy ,
Stainless
Shapes. Plates and Piling
Bars and Tool Steel .
Pipe and Tubing
Wire and Wire Products
Tin Mill Products
Sheets and Strip
Automotive ..
Steel Service Centers"
Construction & Contractors' Products**
Containers & Packaging
Industrial & Electrical Machinery & Equipment
Average Number of Employees (thousands)
Annual Wages and Salaries (billions)
Total Employment Cost/Hr. Worked (hrly employees)
Net Assets (billions)
Total Revenue (billions)
Net Income (millions)
Capital Expenditures (billions)
Total Dividends Paid (millions)
Profit Per Dollar of Revenue
Percent Return on Stockholders' Eouitv^
Capital Expenditures (millions)
Water (millions)
Air (millions)
•••^•••••^^•••^•MB^BHMB^^B^B^^^MMMa^^H^^H^HMI^^Hi^HMVBMHM
Imports, All Steel Mill Products
Carbon
Alloy
Stainless
Dollar Value (billions)
Exports. All Steel Mill Products
Dollar Value (millions)
1976
86.9
128.0
23.5
79.9
24.6
14.5
753.1
89.4
80.3
8.1
1.0
11.3
14.2
6.3
2.5
6.4
42.3
21.4
14.6
12.0
6.9
7.9
454
$8.3
$11.74
$27.5
$36.5
$1,329
$3.3
$631
3.6rf
7 7%
$489.2
$158.7
4»*^1ft c
14.3
13.6
.483
.175 ,
$4.0
2.7
$1,255
1975
79.9
116.6
22.1
71.8
22.7
14.4
712.0*
80.0
70.8
8.4
.8
13.9
13.4
8.2
2.2
5.7
30.8
15.2
12.7
12.0
~6.r
7.3
457
$7.4
510.59
S25.1
$33.7
$1,595*
$3.2
$658
4.7rf
9.8%
$453.1
$131.8
$321.3
!2.0
11.4
.448
.167
$4.1
3.0
$1,862
1974
95.9
145.7
35.5
81.6
28.7
15.0
782.8
109.5
98.0
10.2
1.3
18.1
18.5
9.8
3.2
7.5
45.0
18.9
20.4
17.6
8.2
9.7
512
$7.9
$9.08
$22.8"
$38.2*
$2,475*
$2.1
$674*
6.5«f*
17.1%
$267.2
$106.9
$160.3
16.0
15.4
.413
.176
$5.1
5.8
$2,118
1973
100.8
150.8
39.8
83.3
27.7
14.8
768.6*
111.4.
100.9
9.4
1.1
16.8
18.2
9.1
3.2
7.3
49.4
23.2
20.4
17.2
7.8
9.7
509
$6.8
$7.68
$21.2*
$28.9*
$1,272
$1.4
$443
4.4rf
9.3%
$100.1
$34.7
$65.4
•••••WBBBBBkBBai
15.1
14.6
.434
.128
$2.8
4.1
$1,004
1972
88.9
133.2
34.9
74.6
23.7
13.1
694.5
91.8
83.2
7.8
.8
13.2
15.5
7.6
3.0
6.1
39.9
18.2
16.8
13.6
6.6
8.2
478
$5.8
$7.08
$20.5
$22.6
$775
$1.2
$402
3.4*
5.8%
$201.8
$57.0
$144.8
•••^^••••••••••••i*
17.7
17.1
.448
.149
$2.8
2.9
$604
1971
81.3
120.4
35.6
63.9
20.9
12.0
639.9
87.0
79.3
7.0
.7
13.6
14.2
7.6
2.8
6.8
35.6
17.5
•14.4
13.6
7.2
7.5
487
$5.2
$6.26
$20.0
$20.4
$562
$1.4
$390
2.8*
4.3%
$161.6
$73.4
$88.2
18.3
17.7
.415
.192
$2.6
2.8
$576
1970
91.4
131.5
48.0
63.3
20.2
12.3
654.2
90.8
83.2
6.9
.7
14.1
14.6
7.8
3.0
7.2
35.1
14.5
16.0
13.4
7.8
7.9
531
$5.2
$5.68
$19.7
$19.3
$531
$1.7
$487
2.84
4.1%
$182.6
$110.0
$72.6
•^•••^••••••••ai
13.4
12.9
.349
.177
$2.0
7.1
$1,019
1969
95.0
141.3
60.9
60.2
20.1
10.3
632.0
93.9
85.1
7.9
.9
14.5
14.4
9.2
3.3
6.6
38.1
18.3
15.8
13.9
7.1
8.5
544
$5.3
$5.38
$18.9
$19.2
$879
$2.0
$488
4.6rf
7.0%
$138.0
$71.0
$67.0
14.0
13.5
.353
.182
$1.7
5.2
$796
1968
88.8
131.5
65.8T
48.8
16.8
11.3
582.5
91.9
83.2
7.8
.8
14.6
13.7
10.1 •:
3.4
7.3
36.6
19.3
14.1 --
14.2
7.9
8.4
552
$5.0
$5.03
$18.5
$18.7
$992
$2.3
$451
5.3rf
8.2%
$101.7
$61.5
$40.2
18.0
17.5
.316
.172
$2.0
2.2
$444
1967
87.0
127.2
70.7t
41.4
15.1
9.7
547.6
83.9
76.0
7.0
.8
14.1
13.1
9.0
3.1
6.6
32.6
16.5
13.4
13.4
7.3
7.8
555
$4.7
$4.76
$17.3
$16.9
$829
$2.1
$480
4.94
6.9%
$94.1
$54.7
$39.4
11.5
11.1
.189
.149
$1.3
1.7
$415
* Revised figure.
t Includes any Bessemer production.
* As of January 1 of each year, rather than
December 31, as in previous issues.
Selected tonnage previously reported under this category now reported in oil and 9** industry.
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse befors completing)
1. REPORT NO.
EPA-600/2 -79-003
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Process Water Quality Requirements for Iron and
Steel Making
5. REPORT DATE
January 1979
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
S. Bhattacharyya
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
IIT Research Institute
10 West 35th Street
Chicago, Illinois 60616
10. PROGRAM ELEMENT NO.
1BB610
11, CONtRACT/GRANT NO.
68-02-2617, Task 2-1
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Pevelopment
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Task Final: 8/77 - 1/78
14. SPONSORING AGENCY CODE
EPA/600/13
15.SUPPLEMENTARY NOTES IERL-RTP project officer is John S. Ruppersberger, MD-62,
919/541-2557.
16. ABSTRACT The repOrt gjves results of a study to: develop information on minimum
water quality requirements for the different unit processes in iron and steel making;
identify data gaps; and recommend research efforts to obtain the required informa-
tion. The study utilized plant visits, literature, the American Iron and Steel Insti-
tute, equipment manufacturers? water chemical suppliers, and consultants. Typical
steel plants do not allocate water on the basis of individual processes or recycle
water from each process on separate circuits: most do not even record volume or
analyze water to individual unit operations. Water is usually distributed to clusters
of processing units. Higher quality water is infrequently used for lower quality appli-
cations in a cascading manner, In some plants, recycling exceeding 98% is practiced
without significant equipment or product quality problems. When equipment problems
arise, the present water control technology can usually solve them. Modern equip-
ment is rugged in design and able to accommodate significant water impurities with
the help of chemical controls. Insufficient information is available on the effect of
water quality on product quality. Water recycling and reuse problems are intimately
related to steel plant waste recycling and air pollution problems. One of the research
recommendations is basic data generation on flow and water analysis.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Pollution
Iron and Steel Industry
Industrial Processes
Water Quality
Water Reclamation
Pollution Control
Stationary Sources
13 B
11F
13H
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThisReport)
Unclassified
26. SECURITY CLASS (Thispage)
Unclassified
21. NO. OF PAGES
67
22. PRICE
EPA Form 2220-1 (9-73)
60
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