&EHV
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 2771 1
Research and Development
EPA-600/S2-81-245 July 1982
Project Summary
An Investigation of Foreign
By- Product Coke Plant and
Blast Furnace Wastewater
Control Technology and
Regulation
Harold Hofstein and Harold J. KdtHmann
* <
This study was to determineHuhore
effective wastewater control tebhnoj-
logies for by-product coke plant andV
blast furnace gas cleaning waste-
waters are being used in foreign plants
than in domestic ones. Some unusual
techniques for the treatment of blast
furnace gas cleaning wastewaters
were found. Aeration of the waste-
water prior to clarification improved
settling and allowed a greater rate of
recirculation. Filtering the wastewater
through slag or flue dust removed
cyanide.
Treatment of by-product coke plant
and blast furnace gas cleaning waste-
water is, in general, not more advanced
in foreign plants than in the United
States. However, blast furnace gas
cleaning water in foreign plants is
generally recycled to a greater degree.
Also, highly qualified and experienced
wastewater treatment plant operators
and high level plant management
involvement were frequently observed
at foreign plants. A noticeable spirit of
cooperation between regulators and
industry was observed in many
countries.
Discussions were held with plant
and corporate personnel at 26 plants
in 14 countries and with regulatory
agencies in 10 of the 14 countries to
determine the regulations imposed
S\
upon\thjb plants, the incentives pro-
vided to reduce pollution loads to
receiving waters, and to investigate
treatment technology.
-* Recommendations for research
projects are made as there appear to
be promising areas for improvement
of wastewater treatment techniques.
This Project Summary was developed
by EPA 's Industrial Environmental
Research Laboratory, Research Tri-
angle Park, NC, to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
In its continuing effort to make
information available on the most
advanced and efficient methods of
reducing water pollution from iron and
steel production, the U.S. EPA's Indus-
trial Environmental Research La bora-
tory, Research Triangle Park, NC,
contracted with Hydrotechnic Corpora-
tion to perform an engineering study of
foreign steel plants. This was to
determine if water pollution control
practices were being employed for by-
product coke plant and blast furnace
wastewaters that were superior to
those used in the U.S. In fulfillment of
this contract, Hydrotechnic visited 25
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plants in 14 countries, excluding the
U.S., Canada, and Eastern Bloc nations.
The plants visited accounted for over 23
percent of all steel produced outside of
the three areas excluded. One of the
plants visited was a by-product coke
plant only and one plant consisted of a
single blast furnace.
Three factors were considered in the
selection of the plants to be evaluated:
1. Based on a literature search and
personal correspondence, the
likelihood of the plants utilizing
exemplary or innovative treat-
ment technology.
2. Based on prior investigation, the
relative abundance or lack of
process water in the plant area.
3. Based on literature, the degree of
environmental concern in the
countries where the plants are
located.
Of the 25 plants visited, 23 provided
information that was useable to permit
evaluation of their wastewater treat-
ment systems. These 23 plants are
listed below by country.
ARGENTINA - Plant requested
anonymity
AUSTRALIA - Broken Hill Pro-
prietary -
Newcastle Works
- Australia Iron &
Steel - Hoskins
Kembla Works
- SIDMAR
- British Steel
- Scunthorpe
Works
- Orgreave
Works
- Pont-a-Mousson
- Italsider
- Taranto Works
- Nippon Kokan KK
- Ogishima
Works
- Sumitomo Metal
Ind. - Kashima
Works
- Kobe Steel Ltd.
- Kakogawa
Works
- Kawasaki Steel
- Chiba Works
- Altos Hornos de
Mexico
- Hoogovens
- ISCOR - Pretoria
Works
- Newcastle
Works
- Vanderbijlpark
Works
BELGIUM
ENGLAND
FRANCE
ITALY
JAPAN
MEXICO
NETHERLANDS
SOUTH AFRICA
SWEDEN - Svenskt Stal
- Norrbottens
Jarnverk
- Surhammars
Bruks -
- Spannarhyttan
TAIWAN - China Steel
WEST GERMANY- Roechling
Burbach
- Thyssen
- Hoesch
Huttenwerke
In addition to visiting plants and
cooperate engineering staffs, and
observing wastewater treatment opera-
tions at the production facilities, nine
government agencies were consulted.
A trade association was consulted in a
tenth country. The agencies provided
information on how regulations influ-
enced the degrees of treatment and on
the incentives provided for increasing
recirculation of water within the pro-
duction facilities.
The nine governments were:
Argentina
Australia (New South Wales)
Japan (two agencies)
Mexico
Netherlands (two agencies)
South Africa
Sweden
Taiwan
At the meeting with the trade associa-
tion, VDEh, an organization of the West
German iron and steel industry, several
steel company representatives and a
representative from the local West
German water and waste agency were
present.
Summary
By-Product Coke Plants
The volume of waste ammonia liquor
produced at foreign by-product coke
plants ranged from 0.14 to 0.24 m3/Mg
(34 to 178 gal./ton). These volumes are
higher than those found in U.S. by-
product coke plants evaluated through
the literature.
The treatment of by-product coke
plant wastes at foreign plants is
basically similar to that practiced in the
U.S. Single stage biological treatment is
used at 14 of the plants visited. Nine of
these 14 add dilution water to reduce
high ammonia concentrations in the
wastewater to levels not toxic to the
organisms. At one plant in Japan, salt
water is used. All plants utilizing
biological treatment add phosphorus as
a nutrient, usually in the form of
phosphoric acid. Two of the plants
pretreat the wastes by filtering the
wastewater through a coarse coke bed.
This procedure removes tar and oil that
may be detrimental to the biological
oxidation process. Two other plants use
tertiary treatment consisting of sand
filtration followed by activated carbon
adsorption.
Of the 23 by-product coke plants for
which some data was available, 14
plants discharged their biologically
treated wastewater to public waters, 5
plants treated their wastewater in free
ammonia stills and then discharged it 1
plant treated its wastewater in both free
and fixed ammonia stills prior to
discharge, 1 plant utilized a free
ammonia still and a dephenolizer prior
to discharge, 1 plant provides no
treatment at all prior to discharge, and 1
plant uses the raw waste ammonia
liquor together with blast furnace
wastewater to irrigate a grass crop that
is used for animal feed, reportedly with
no ill effects to the animals.
Blast Furnaces
Blast furnace gas cleaning systems
were used at all of the plants visited. The
gas washer wastewater application
rate varied depending on the type of wet
gas cleaning system used. The rates
varied from 2.1 to 28 m3/Mg (507 to
6715 gal./ton) of iron produced with an
average application rate of 6.09 m3/Mg
(1460 gal./ton).
All but one of the plants visited treat
their gas washer wastewater for solids
removal prior to reuse or discharge. The
plant that does not treat is under
government directive to provide treat-
ment within the next 2 years. Of the 23
blast furnace installations studied, 3 do
not recycle their wastewaters. The
remaining 20 plants have recycle rates
ranging from 27.4 to 99.2 percent with
an average rate of 92.4 percent. Of
these plants, 12 had recycle rates equal
to or exceeding 98 percent.
Two of the plants treat their blow-
downs for cyanide removal. One uses
alkaline chlorination and one uses
Caro's acid (H2SO5). Three other plants
reported unexpected cyanide reductions
which were not due to planned treat-
ment. One reported that the cyanide
reduction is a result of seepage of water
through the accumulated sludge in its
flue dust ponds, one reported cyanide
reduction due to sparging of steam in its
clarifier to prevent freezing, and the
third reported cyanide reduction when
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the gas washer wastewater blowdown
was used to quench slag.
Regulatory Agencies
Regulatory agencies of nine foreign
governments were visited to gain
insight into the regulatory climate and
the relationship that these agencies
have with industry. This information
provides a better understanding of the
individual plant pollution control practices.
Countries that are members of the
European Economic Community (EEC)
have been issued a policy directive with
regard to control of water pollution in
the EEC. To date, the regulations of the
individual countries have taken prece-
dence over the EEC directive.
In addition to the regulatory agencies,
VDEh, a West German trade association
which represents the iron and steel
industry, was visited. Attending the
meeting with VDEh were representatives
from several steel corporations and a
representative of a local West German
Federal Government authority.
Only 2 of the 10 countries, Argentina
and South Africa, from which regula-
tions were obtained have or will have
regulations specific to the iron and steel
industry. All others have regulations
which pertain to the quality of water
discharged to, or the effect of the
discharge on, the receiving body. The
regulations are based on the use that is
made of the receiving body; e.g., potable
water, fishing, recreation.
Input from outside of government and
industry reportedly had little effect on
establishing regulations. Generally, the
bases for regulations are: preservation
of public health, minimizing environ-
mental effects, aesthetic considerations,
and water conservation. The economic
impact of the regulations on the
individual plant, the industry, and the
country is considered.
All agencies reported that the indus-
tries or individual companies to be
affected by proposed regulations are
consulted prior to establishing regula-
tions.
In all the countries, variances to the
regulations are subject to negotiation
both prior and subsequent to promulga-
tion. They may be based on available
technology and/or economic conditions.
The final regulations that apply to the
individual plants may be referred to
differently in each country e.g., in
England, they are called "consent
conditions," and in South Africa,
"relaxed standards."
Comparison between Foreign
and U.S. Treatment
A comparison of foreign and U.S. by-
product coke plants and blast furnace
wastewater treatment systems reveals
that:
- In general, the treatment applied
to these wastewaters in foreign
plants is similar to that used in
U.S. plants.
- Effluents from foreign plants are
not monitored for pollutant content
to the same degree that U.S.
plants are; i.e., more parameters
are monitored in the U.S. than in
foreign countries.
- Foreign plants generally recircu-
late blast furnace gas washer
water to greater degrees than do
U.S plants.
- Waste treatment plant operators
at foreign plants are well trained
and qualified. They communicate
closely with plant management.
Table 1 shows the comparative com-
pliance with U.S. effluent guidelines
limitations as presented in the "Devel-
opment Document for Proposed Effluent
Limitations and Standards for the Iron
and Steel Manufacturing Point Source
Category" (EPA-440/1 -80-024-b, De-
cember 1980) for the foreign plants
observed and the plants for which
detailed data was available in the U.S.
Water use efficiency is indicated by
comparing the degrees of EPA compli-
ance to mass limitations. A larger
portion of the foreign blast furnace
treatment systems that meet the
guidelines limitations at Best Available
Technology (BAT) levels with respect to
concentrations also meet the guidelines
limitations with respect to mass dis-
charges for suspended solids and
cyanide. This indicates that less water is
being discharged per unit of production
resulting in the lower mass discharges.
Innovative Technology
Blast Furnaces
A unit operation, not known to be
practiced in the U.S., was observed at
two foreign plants, August Thyssen in
West Germany and Chiba Works of the
Kawasaki Steel Corporation. It is the
aeration of gas washer water prior to
settling in clarifiers or thickeners. A
portion of the settled sludge is recircu-
lated to the aeration basin to act as a
seed for precipitation of .carbonates.
This operation increases the cycles of
concentration while not increasing the
likelihood of scale formation inthe recir-
culation system.
Four methods of cyanide removal,
other than alkaline chlorination, from
gas washer wastewater were noted.
Three of these methods were not
utilized as intentional unit operations,
i.e., the operation was not for the
specific purpose of cyanide removal,
although removal was noted. These
operations are:
• Sparging steam through the waste.
At one plant in Sweden (Spanna-
rhyttan) cyanide reduction was
noted after steam sparging. Steam
was utilized to prevent freezing of
water in the clarifier and apparently
resulted in cyanide reduction from
an influent concentration of 30
mg/l down to 2.4 mg/l.
• Filtration of blast furnace waste-
water through flue dust. Two plants
owned by Hoesch-Estel in West
Germany utilize sludge disposal as
a means of blast furnace gas
washer water blowdown. The
sludge is discharged to flue dust
ponds and the excess water that
seeps through is collected in an
underdrain pipe and discharges to a
river. Alkalinity is added at both
plants: at one, in the form of cold
mill sludge; and at the other, in the
form of caustic (sodium hydroxide).
The cyanide concentration in the
liquid phase of the sludge was 0.2
mg/l, and the cyanide concentration
of the underdrain flow was 0.1
mg/l. The plant has theorized that
the reduction is due to metallo-
cyanide complexes being formed
and adsorbed on the flue dust. No
work has been done to confirm this
hypothesis.
• Use of gas washer wastewater for
slag quenching. One plant, ISCOR-
slag quenching. One plant, ISCOR's
Pretoria Works in South Africa,
reported that, when a portion of the
gas washer wastewater blowdown
is used for slag quenching, the
leachate from the slag pile is free of
cyanide. The plant has not reported
the cyanide content of the raw
water but stated that they believe
that the lack of cyanide in the
leachate is due to biological activity
in the slag pile. No work has been
done by the plant to verify this
hypothesis. The authors disagree
with this theory; they feel that
biological organisms would not
likely be found in recirculating gas
washer water or in molten slag. The
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Table 1, Comparative Compliance of Foreign and U.S. By-Product Coke Plant and Blast Furnace Wastewater Treatment Facilities
with U.S. EPA Draft Effluent Guidelines for BPT and BA T
Area
Foreign
U.S.
Foreign
U.S.
Foreign
U.S.
Foreign
U.S.
Coke Plant Level
or Blast of
Furnace Treatment
Coke Plant BPT
BAT
Blast Furn. BPT
BAT
Susp.
Solids
5
100% 100%
6
83% 67%
5
40% 80%
6
17% 17%
12
83% 67%
6
83% 50%
12
8% 25%
6
17% 0
Total
Cyanide
7
100% 100%
6
100% 83%
7
100% 86%
6
67% 17%
12
100% 100%
6
83% 33%
12
42% 42%
6
50% 17%
OH&
Grease
3
67% 67%
5
60% 80%
3
67% 67%
5
60% 80%
0
0
0
0
— —
Phenolics
0
3
33% 33%
0
3
0 0
0
6
100% 83%
0
6
67% 50%
Ammonia
9
13% 22%
6
50% 50%
9
0 11%
6
33% 17%
4
100% 75%
5
80% 80%
4
0 0
5
20% 0
NOTE: The data presented in this table are based on information from a limited number of plants.
The U.S. plants are only those for which data were available from the U.S. EPA Development Documents.
The data for foreign plants are for those that were visited during the course of the study and constituted plants thought to
have superior technology.
No. of plants for which
data is available
% that meet % that meet
concentration limit mass limit
gas washer water is subjected to
temperatures too high to allow
biological growth intherecirculating
system.
• Pont-a-Mousson in France uses
Caro's acid (H2SO5) for cyanide
destruction. The plant discharges a
quantity of gas washer water from
the flue dust settling pond, on a
batch basis, to chemical treatment
tanks where the acid is added. It
reacts with and oxidizes the cya-
nide. In the process, some phenol,
reduction is also observed.
Coke Plants
Of the 23 by-product coke plants
observed, 14 utilize, biological methods
to treat their wastewater. At China Steel
in Taiwan and at Kawasaki Steel
Corporation's Chiba Works, wastes are
pretreated by filtration through a bed of
coke to remove excess tars that might
interfere with the biological process. At
China Steel, after the filtration step,
sanitary wastes from the entire plant
are combined with the coke plant
wastes and treated in an activated
sludge process.
One plant combines untreated coke
plant wastewater with blast furnace gas
washer water blowdown and uses the
combined wastes to irrigate grass fields.
The grass crop is used for cattle fodder.
No ill effects to the cattle have been
reported. This method cannot be con-
sidered as innovative treatment but
rather as a means of disposal, novel to
the steel industry.
Other Observations
John Lysaght (Aust.) Ltd. of Australia
was visited to discuss the hot and cold
mill water systems at its Westernport
Bay Facility. The hot strip mill operates
with the lowest blowdown of any such
facility in the world and features four
recirculating water systems. One is a
completely closed non-contact cooling
water system for reheat furnace skid
cooling. The water of the other three
systems is cascaded with the makeup
water consisting of a mixture of a
purchased supply and collected storm
water. The makeup is applied tothe area
where highest quality water is required.
Blowdown is cascaded from high water
quality systems to facilities which may
tolerate lower quality. The contact
cooling water is filtered, cooled, and
recirculated. Blowdown from the system
discharges to Westernport Bay via the
plant's cold mill effluent lagoon. The
plant reports that the total discharge
from the mill of 0.2 m3/Mg (48 gal./ton)
with mass discharges of 0.002 kg/Mg
(lb/1000 Ib) each of suspended solids
and oil.
The cold mill complex (consisting of a
hydrochloric acid pickler, a five-stand
cold reduction mill, a coating line, and a
paint line) is also an excellent example
of conservation and reuse which also
results in significant pollution control.
The key to minimizing plant water use is
the segregation of water systems. All
non-contact cooling water is collected,
cooled, and reused in a separate
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system. Sanitary sewage is collected
and treated separately. Waste pickle
liquor is regenerated in a hydrochloric
acid regeneration plant.
The process water is treated in two
separate systems. One is the industrial
water treatment system in which the
relatively clean wastewater from stands
1 and 5 of the cold mill and the pickler
process water are treated, cooled,
combined with tertiary treated sanitary
wastes, and returned to the mill for
reuse. The second wastewater treat-
ment system receives the cold mill
rolling solution blowdown and dumps,
the pickle liquor regeneration plant
excess rinse water, galvanizer alkali
dumps, and the industrial water treat-
ment plant blowdown. These wastes
are treated for discharge to receiving
waters.
Plant and corporate managements
are intimately familiar with wastewater
treatment practiced at the individual
plants and are usually apprised of
potential problems before they actually
occur. Operators, in many cases, are
familiar with the theoretical as well as
the practical aspects of the treatment
plant operations. Therefore, even
though the technologies observed are
not considered to be more advanced,
they do produce, according to the data
provided, higher quality affluents.
Generally, housekeeping was ob-
served to be of a high order. Water was
not running where it was not needed. In
plants where space permitted, green
areas were set asid£ both to enhance
the appearance of the physical plant and
to reduce noise in the plant environs.
In one blast furnace cast house, all
runners were covered with hoods and a
vacuum applied. This resulted in a
noticeable lack of fugitive emissions.
Conclusions
Based on observation at 25 foreign
plants visited that operate by-product
coke plants, blastfurnaces, or both, it is
concluded that the wastewater treat-
ment practiced in foreign plants is
basically similar to that practiced in the
U.S. Generally, blast furnace gas
washer water is recirculated to a
greater degree than at U.S. plants.
Two plants in Japan reported that the
by-product coke plant wastewater
passed through a tertiary treatment
phase; i.e., sand filtration followed by
activated carbon adsorption. Of all the
plants observed or reported, these were
the only plants that apparently addressed
the problem of priority pollutants;
however, no data with regard to the
efficiency of removal of priority pollu-
tants or effluent levels was provided
when requested.
Foreign requirements with respect to
effluent quality are usually negotiated
between government and industry for
each plant on a case by case basis. The
economic impacts of the requirements
are a major concern.
Recommendations
Research should be conducted to
quantify the pollutant reductions attain-
able and to ascertain the mechanisms
by which the reduction of cyanide
occurred for two of the methods
observed:
• Sparging of steam through waste-
water. Research on this method
should also include effects on air
quality and energy requirements.
• Filtering the wastewater through
flue dust. The research on this
method should also include possible
effects on air quality at sinter plants
or briquetting plants if the flue dust
containng cyanide is used as a feed
stock.
Research should also be conducted to
determine the effect of increased recir-
culation at blast furnace gas washer
operations. Specifically, the method of
increasing recirculation by aerating the
solids laden gas washer water prior to
settling should be investigated.
Treatment of by-product coke plant
wastes by biological means is a generally
accepted and proven procedure. How-
ever, the authors believe that coke plant
wastewater can be combined with blast
furnace gas cleaning blowdown water
prior to treatment. This treatment
concept was raised Curing discussions
with steel plant personnel in the U.S. in
the past and abroad during this study.
The only objection was that heavy
metals present in blast furnace waste-
water might be toxic to the biological
systems. However, lime precipitation
should precipitate the heavy metals that
are regulated to permissible discharge
levels and, in addition, are not toxic to a
biological system. If this unit operation
is provided, and the pretreated blast
furnace wastewaters are combined
with by-product coke plant wastes for
biological treatment, then chlorination
for removal of other oxidizable para-
meters would not be necessary. De-
chlorination would also not be required.
This concept should be confirmed by a
well conceived research program.
Further research should also be under-
taken to verify a second stage biological
process to nitrify ammonia in the
combined wastewater streams.
Harold Hofstein and Harold J. Kohlmann are with Hydrotechnic Corporation,
New York, NY 10001.
John S. Ruppersberger is the EPA Project Officer (see below).
The complete report, entitled "An Investigation of Foreign By-Product Coke
Plant and Blast Furnace Wastewater Control Technology and Regulation,"
(Order No. PB 82-221 771; Cost: $18.00, subject to change) will be available
only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
•US.OOVERNMENT MINTING OFFICE:1M2-$S»-0»2-424
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