SUMMARY OF TECHNOLOGIES
FOR THE CONTROL AND
REDUCTION OF CHLORINATED ORGANICS
FROM THE BLEACHED CHEMICAL PULPING
SUBCATEGORIES OF THE
PULP AND PAPER INDUSTRY
April 27,1990
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Water Regulations and Standards
Office of Water Enforcement and Permits
401 M Street S.W.
Washington, D.C. 20460
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SUMMARY OF TECHNOLOGIES
FOR THE CONTROL AND
REDUCTION OF CHLORINATED ORGANICS
FROM THE BLEACHED CHEMICAL PULPING
SUBCATEGORIES OF THE
PULP AND PAPER INDUSTRY
April 27, 1990
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Water Regulations and Standards
Office of Water Enforcement and Permits
401 M Street S.W.
Washington, D.C. 20460
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TABLE OF CONTENTS
I. INTRODUCTION/BACKGROUND 7
H. CHLORINATED ORGANIC COMPOUNDS PRODUCED IN BLEACHED CHEMICAL PULP MILLS.. 9
m. REGULATIONS FOR CHLORINATED ORGANICS FROM PULP MILLS 14
IV. MINIMIZATION OF CONTAMINATION FROM EXTERNAL SOURCES
WOOD SOURCES 17
SELECTION AND USE OF ADDITIVES 17
V. MINIMIZATION OF CONTAMINATION THROUGH PROCESS CHANGES -JJULPJiQ.
AVAILABLE TECHNOLOGIES
EXTENDED DELIGNIFICATION 20
^XYGEN DELIGNIFICATION 25
POLYSULFIDE COOKING 34
IMPROVED PULP WASHING 36
EMERGING TECHNOLOGIES
PRETREATMENT WITH NITROGEN DIOXIDE (PRENOX) 38
DEMETHYLATION 41
ANTHRAQUINONE (AQ) CATALYSIS 42
^OZONE DELIGNIFICATION 43
PEROXIDE DELIGNIFICATION 44
VI. MINIMIZATION OF CONTAMINATION THOUGH PROCESS CHANGES - BLEACHING—
AVAILABLE TECHNOLOGIES
CHLORINE DIOXIDE SUBSTITUTION 46
OXYGEN EXTRACTION 53
PEROXIDE EXTRACTION 55
MONOX-L SUBSTITUTION 57
CONTROL OF CHEMICAL DOSAGE 60
IMPROVED MIXING 62
SPLIT CHLORINE ADDITION/pH CONTROL 63
MONITORING OF CHLORINE MULTIPLE 66
EMERGING TECHNOLOGIES
SLC EXTRACTION PROCESS 69
CLOSED CYCLE TECHNOLOGY (RAPSON/REEVE) 70
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VH. WASTEWATER TREATMENT TECHNOLOGY
PHYSICAL/CHEMICAL TREATMENT
ULTRAFILTRATION 72
CHEMICALLY ASSISTED CLARIFICATION 75
ENHANCED PHOTOOXIDATION 79
BIOLOGICAL TREATMENT
AEROBIC TREATMENT. 80
ANAEROBIC TREATMENT. 83
TABLE OF CONTENTS - TABLES
TABLE H-l BLEACHING SYMBOLS 11
TABLE H-2 SIZE DISTRIBUTION OF ORGANICALLY-BOUND CHLORINE FROM BLEACHING
SOFTWOOD KRAFT PULP. 13
TABLE m-1 LEVELS OF ACHIEVEMENT FOR ONTARIO KRAFT PULP AND PAPER
MILL EFFLUENTS 16
TABLE IV-1 DEBENZOFURAN ANALYSIS OF DEFOAMERS 18
TABLE V-l CHARACTERISTICS OF UNTREATED EFFLUENT FROM A BLEACHED
SOFTWOOD KRAFT PULP MILL SHOWS ADDITIVE EFFECTS FROM
DIFFERENT IN-PROCESS MODIFICATIONS 21
TABLE V-2 WORLDWIDE EXTENDED DELIGNIFICATION - MODIFIED CONTINUOUS COOK
(MCC) REFERENCE LIST. 22
TABLE V-3 WORLDWIDE EXTENDED DELIGNIFICATION - RAPID DISPLACEMENT HEATING
(RDH) REFERENCE LIST. 23
TABLE V4 DIOXIN/FURAN SURVEY DATA FOR THREE BLEACHED KRAFT MILLS WITH
OXYGEN DELIGNIFICATION 27
TABLE V-5 EXTENDED DELIGNIFICATION, OXYGEN DELIGNIFICATION AND
BIOLOGICAL WASTEWATER TREATMENT AT SWEDISH BLEACHED
KRAFT PULP MILLS 28
TABLE V-6 WORLDWIDE OXYGEN DELIGNIFICATION REFERENCE LIST. 29
TABLE V-7 OXYGEN DELIGNIFICATION CAPITAL COSTS 32
TABLE V-8 WORLDWIDE POLYSULFIDE COOKING REFERENCE LIST. 35
TABLE V-9 THE EFFECT OF BROWNSTOCK WASHING ON THE FORMATION OF 2378-TCDD
IN PULPS 36
TABLE V-10 THE IMPACT OF PRENOX ON CHEMICAL COST AND EFFLUENTS 39
TABLE VI-1 CHLORINE DIOXIDE SUBSTITUTION AT U.S. KRAFT MILLS (MID 1988) 47
TABLE VI-2 AOX AND BODS FOR VARIOUS LEVELS OF CHLORINE DIOXIDE SUBSTTrUTION... 48
TABLE VI-3 DIOXIN AND FURAN RESULTS FOR VARIOUS LEVELS OF CHLORINE DIOXIDE
SUBSTITUTION 50
TABLE VW MILL TRIAL CHANGES IN BLEACHING CHEMICAL CONSUMPTION AND COSTS... 51
TABLE VI-5 AOX LEVELS IN FILTRATES FOR BLEACHED SCANDINAVIAN SOFTWOOD 57
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TABLE VI-6 C-STAGE SUBSTITUTION WITH MONOX-L 58
TABLE VI-7 WESTVACO (LUKE, MD) DIOXIN/FURAN ANALYSES 64
TABLE VI-8 WORLDWIDE STFIOPTI-KAPPA INSTALLATIONS REFERENCE LIST. 67
TABLE VII-1 ULTRAFTLTRATION TRIAL RESULTS 72
TABLE VH-2 EFFLUENT REDUCTION DATA FOR COMMERCIAL ULTRAFILTRATION PLANT. 73
TABLE VH-3 USEPA BENCH SCALE WASTEWATER TREATABE.ITY STUDY RESULTS 76
TABLE Vn-4 NCASI RESULTS OF 2378-TCDD AND 2378-TCDF ANALYSES FOR TREATMENT
OF KRAFT MILL "A" EFFLUENTS 77
TABLE VH-5 LRP EFFLUENT TREATMENT RESULTS 78
TABLE VH-6 TYPICAL PARAMETERS FOR PULP AND PAPER BIOLOGICAL WASTEWATER
TREATMENT PLANTS 80
TABLE OF CONTENTS - FIGURES
FIGURE 1-1 EFFECT OF KAPPA NUMBER AND CHLORINE DIOXIDE SUBSTITUTION
ON FORMATION OF TOCL 8
FIGURE n-1 KRAFT PULP MILL, INCLUDING CONVENTIONAL BLEACH PLANT. 11
FIGURE VI-1 CHLORINE DIOXIDE IN THE CHLORINATION STAGE 47
FIGURE VI-2 THE EFFECT OF CHLORINE DIOXIDE SUBSTITUTION ON TOTAL AND
TETRACHLORINATED PHENOLIC COMPOUNDS 49
FIGURE VI-3 THE EFFECT OF CHLORINE DIOXIDE SUBSTrrUTION ON THE FORMATION
OF AOX 50
FIGURE VI-4 THE EFFECT OF CHLORINE MULTIPLE ON 2378-TCDD IN PULP. 61
FIGURE VH-1 2378-TCDD IN ACTIVATED SLUDGE AND AERATED STABILIZATION BASIN
WASTEWATER EFFLUENTS 80
ATTACHMENT
ATTACHMENT A REFERENCES 84
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GLOSSARY OF ACRONYMS AND ABBREVIATIONS
ADBSP air dried brownstock pulp
ADMT air dried metric tons
ADST air dried short tons
AOX adsorbable organic halogen
AQ anthraquinone
ASB aerated stabilization basin - A natural or man made wastewater treatment pond in which mechanical or
diffused air is used to supplement the oxygen supply.
BAT Best Available Technology Economically Achievable
BOD or BODS biochemical oxygen demand (five day) - The amount of dissolved oxygen consumed in five days by
biological processes breaking down organic matter under standard conditions.
BOD7 biochemical oxygen demand (seven day) - The amount of dissolved oxygen consumed in seven days
by biological processes breaking down organic matter under standard conditions.
C chlorine - A bleaching stage where pulp is treated with gaseous chlorine, primarily to oxidize the
residual lignin, so that it can later be dissolved and extracted with sodium hydroxide.
CAC chemically assisted clarification
C/D Sequential addition of chlorine and chlorine dioxide in the same bleaching stage.
CDD chlorinated dibenzo-p-dioxin
CDF chlorinated dibenzofuran
CDN$ Canadian dollars - As of 29 March 1990,1 CDN$ = $0.850
CEK No. caustic extraction K-number - A parameter monitored in bleaching operations after the chlorine stage
which can be used to determine how much chlorine or chlorine dioxide to add.
COD chemical oxygen demand - A measure of the oxygen equivalent of that portion of the organic matter
in a sample that is susceptible to oxidation by a strong chemical oxidant. ^
CTMP chemi-thermomechanical pulp
D chlorine dioxide • A bleaching stage where the pulp is treated with chlorine dioxide, applied in an
aqueous solution.
DBF unchlorinated dibenzofuran
DBD unchlorinated dibenzo-p-dioxin
D/C Sequential addition of chlorine dioxide and chlorine in the same bleaching stage. Implies greater than
20% chlorine substitution.
E caustic extraction - A bleaching stage involving dissolution of reaction products with sodium
hydroxide.
Eo caustic extraction with oxygen enhancement - Also referred to as oxygen extraction.
EOC1 extractable organic chlorine
EQP peroxide reinforced oxygen extraction
EOX extractable organic halogens
EP caustic extraction with peroxide enhancement
gfedt grams per air dried metric ton
GE Unit of brightness determined by use of a General Electric reflectance meter
GJ gigijoules = one billion joules
H hypochlorite - A bleaching stage involving the treatment of pulp with sodium or calcium
hypochlorite.
ISO Unit of brightness (International Organization for Standardization). Uses different optical geometry
and different reference standard than TAPPI or GE method. ISO brightness is slightly lower than GE
brightness.
K No. permanganate number
kg/ton kilogram per metric ton
kwH kilowatt hour
L hypochlorous acid - A bleaching stage involving the treatment of pulp with hypochlorous acid.
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LRP Lignin Removal Process - A proprietary process for the precipitation of high molecular organic
compounds.
m3/adt cubic meters per air dried metric ton
mg/1 milligrams per liters ppm
MCC Modified Continuous Cook • A proprietary process for extended delignification in a continuous
digester.
MGD million gallons per day
N nitrogen dioxide - A bleaching stage where the pulp is treated with nitrogen dioxide.
ng/1 nanograms per liter = ppt
NCASI National Council of the Paper Industry for Air and Stream Improvement, Inc.
ND nondetect
NQ not quantified
NTU nephelometric turbidity units
O oxygen - A bleaching stage where the pulp is treated with elemental oxygen, in alkaline conditions.
od oven dry
OD oxygen delignification
P peroxide - A bleaching stage where the pulp is treated with hydrogen or sodium peroxide.
PAPRICAN Pulp and Paper Research Institute of Canada
PCDD polychlorinated dibenzo-p-dioxin - Includes all isomers of which there are 75.
PCDF polychlorinated dibenzofuran - Includes all isomers of which there are 135.
PCU platinum cobalt color units - A unit of measurement for color which also can be expressed as mg/1.
pg/1 picograms per liter=ppq
ppb parts per billion (10"9)
ppm parts per million (10*6)
ppq parts per quadrillion (10~1S)
ppt parts per trillion (10"12)
RDM Rapid Displacement Heating - A proprietary extended delignification process for batch digestion
systems.
ROI return on investment
SEK Swedish kroner - As of 29 March 1990,1 SEK = $0.162
S LC Suppressed Lignin Condensation - A proprietary process designed to reduce the amount of dissolved
lignin which precipitates back into the fibers after the chlorine stage of bleaching.
SNV Statens Naturvardsverk (Swedish National Environmental Protection Board)
STFI Skogsindustrins Tekniska Forskningsinstitut (Swedish Pulp and Paper Research Institute)
s.u. standard units
TAPPI Technical Association of the Pulp and Paper Industry
TCDD tetrachlorodibenzo-p-dioxin
TCDF tetrachlorodibenzofuran
TMP thermomechanical pulping
TOC1 total organic chlorine
tonne metric ton
TOX total organic halogen
(ig/g micrograms per gram = ppm(10~6)
Y hydrosulphite - A bleaching stage where the pulp is treated with sodium or zinc hydrosulphite.
Z ozone - A bleaching stage where the pulp is treated with ozone under acid conditions.
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I. INTRODUCTION/BACKGROUND
The purpose of this report is to identify and describe technologies and/or processes under evaluation, development or
in use with potential to reduce or eliminate the formation of chlorinated organics during the chlorine bleaching of
chemically produced pulps. A manual literature search as well as a computerized literature search of the following
data bases was performed: (1) PAPERCHEM, (2) NTIS, (3) CHEM ABSTRACTS, (4) DISSERTATION
ABSTRACTS, AND (5) PAPRICAN. Applicable articles were obtained and a list of those articles the majority of
which were used in developing this paper can be found in Attachment A.
The literature does not reveal any single process that can entirely eliminate chlorinated organics as well as maintain
the final high brightness needed to produce quality market pulp and/or paper. These chlorinated organics are usually
measured as Total Organic Chlorine (TOC1) or as Adsorbable Organic Halogen (AOX). Numerous studies have
shown that the formation of chlorinated organics are reduced with reduced elemental chlorine (C12)
consumption.17-19•22'92 The two main approaches described in the literature to decrease chlorine consumption are: (a)
process modifications which reduce the amount of lignin in pulp entering the bleach plant, thus, minimizing
bleaching chemical demand (e.g., oxygen delignification and extended delignification); and (b) process modifications
which minimize the consumption of chlorine and chlorine bleaching products during bleaching (e.g., chlorine dioxide
substitution and alkaline extraction in the presence of oxygen). Figure 1-1 shows how various process
modifications can aid in reducing formation of TOG.
Brief descriptions of each technology are provided in the following pages. In addition to a description of the
technology, the relative effectiveness of the technology, installations, implementation and cost of the technologies
identified, are discussed where information was available. The effectiveness of each technology was assessed on the
basis of it's ability to reduce chlorinated organics or chlorine consumption. The section on installation lists
facilities where the technology is presently in operation, under construction or planned. Implementation was
assessed on the basis of the compatibility and/or impact on other processes, effects on pulp, availability, time to
implement and limitations. The section on costs covers capital and operating costs where information was available.
A list of recent literature references keyed to Attachment A, is also presented for each technology.
Those technologies that have been developed and studied on a mill-scale basis and are being applied in the industry
have been included in this report under Available Technologies. Other technologies, including alternate pulping and
bleaching technologies which have not been demonstrated on a commercial scale, are referred to as Emerging
Technologies.
Those unfamiliar with the pulp and paper industry are advised to consult Reference's 92, 131 and 145 from which
much of the introductory material in this report was abstracted, and Reference 138 which presents the results of the
first comprehensive dioxin study of pulp and paper mills.
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TOCI. kg/t
LEGEND
COHV. CONVENTIONAL KRAFT COOKMG
Mod. MODIFIED KRAFT COOKWG
Oj OXYGEN BLEACHING
Pr«nox NO, PRETREATMENT + O,
10 0
Unbleached Kappa. No.
FIGURE 1-1 EFFECT OF KAPPA NUMBER AND CHLORINE DIOXIDE SUBSTITUTION
ON FORMATION OF TOC1"
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II. CHLORINATED ORGANIC COMPOUNDS PRODUCED
IN BLEACHED CHEMICAL PULP MILLS
WOOD COMPOSITION
The principal components of wood are cellulose, hemicelluloses, lignin, and extractives. Cellulose, a linear
polysaccharide, is the characteristic wall material of plant cells. Cellulose molecules are bundled together in wood to
form microfibrils, which in turn build up to form fibrils, and finally cellulose fibers. About 40% of most wood is
cellulose.92
Hemicelluloses, also polysaccharides, are composed of different carbohydrate units. Unlike cellulose, hemicelluloses
are branched to various degrees and their molecular masses are much lower. Hemicelluloses can also be distinguished
analytically from cellulose by their greater ease of hydrolysis in hot dilute acid solutions, and their solubility in
aqueous alkaline solutions. The content and types of hemicellulose in softwoods differ considerably from those in
hardwoods.92
Lignin is an amorphous partly aromatic polymer. It imparts rigidity to the fiber walls and acts as a bonding agent
between fibers. Lignin is partly soluble in aqueous alkaline solutions, condenses in mineral acids and is readily
attacked and solubilized by oxidizing agents. The relative molecular mass of native lignin is considered infinite.92
"Extractives" are those low molecular components of wood that can be extracted with water or organic solvents such
as ethanol, acetone, or dichloromethane and excludes those components defined as hemicellulose or lignin. 131 The
amount of extractives in wood varies greatly (1.5-5%), depending upon species, place of growth, and age of the
tree.92 Extractives include aliphatics consisting of fats and waxes; phenolic extractives, which include hydrolyzable
tannins, flavonoids, ligands, stilbenes, and tropolines; and, terpenoid compounds found only in softwoods, which
include mono-, sesqui-, and diterpenes, as well as various resin acids.92
WOOD PTILPTNfl
Most chemical pulping in the United States is currently carried out by the kraft (sulfate) or the sulfite process. The
purposes of pulping are to remove lignin in order to facilitate fiber separation and to improve the papermaking
properties of the fibers. The kraft process is the most widely used commercial process, by far. In the United States,
there are 87 bleached kraft mills and 17 bleached sulfite mills. 126 Kraft pulping entails treating wood chips at 160-
180° C with a liquor containing sodium hydroxide and sodium sulfide, which promotes cleavage of the various ether
bonds in the lignin. The lignin degradation products so formed dissolve in the alkaline pulping liquor. Depending
upon pulping conditions, as much as 90-95% of the lignin can be removed from wood in kraft pulping.92
-.
Portions of the wood polysaccharides, especially those associated with the hemicelluloses, and most of the wood
extractives are dissolved in the kraft pulping liquor. If softwood is the raw material, the extractives can be recovered
as by-products such as sulfate turpentine and tall oil. Turpentine contains a mixture of the lower terpenes, whereas
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raw tail oil consists mainly of fatty and resin acids. The content of residual extractives in unbleached (brownstock)
pulp is low.92
In kraft pulping for production of bleached pulp, more than 55% of the total weight of wood is dissolved in the
pulping liquor After separation from the pulp, the spent liquor is evaporated to a high concentration and then burned
in a recovery boiler to recover energy and inorganic chemicals which are used to re-constitute fresh pulping liquor.92
By comparison, the sulfite process solubilizes lignin through sulfonation at elevated temperatures. The pulping
liquor contains sulfur dioxide and alkaline oxides (sodium, magnesium, or calcium).92 With the exception of sulfite
mills using a calcium based cooking liquor, the cooking liquor is evaporated and burned in a recovery boiler to
recover energy and inorganic chemicals which are used to make up new cooking liquor
The lignin content of unbleached or brownstock pulps is characterized by the kappa number, or the permanganate (K)
number. Kappa numbers for unbleached softwood kraft pulps are generally in the range of 28 to 35, while those for '
hardwood kraft pulps may range from 14 to 18. For softwood pulps, permanganate numbers are about one third
lower than corresponding kappa numbers, and, for hardwood pulps about 30% lower
PULP BLEACHING
As noted above, not all of the lignin is removed from wood during chemical pulping. About five to ten% of the
original lignin remains in the pulp since it cannot be removed by extended conventional pulping without degrading
the polysaccharide fraction. Removal of the residual lignin that is responsible for the dark color of kraft pulps,
requires a multistage bleaching process.92 Figure II-l illustrates conventional kraft pulping and bleaching
processes for producing bleached softwood pulps. In virtually all kraft mills, bleaching is accomplished by
successive treatments of the kraft pulps in slurry form with chlorine (C) and alkali extraction (E) (sodium hydroxide),
followed by other bleaching stages which may include chlorine dioxide (D), sodium or calcium hypochlorite (H), and
hydrogen peroxide (P). A list of the symbols used to denote bleaching stages is shown in Table II-l.
The first C and E-stages of a normal bleach sequence constitute prebleaching and all subsequent stages collectively
are referred to as final bleaching. Additional extraction stages are usually included in long sequence bleach lines.
After each bleaching or extraction stage, the pulp is washed using either fresh water or recirculated water from other
bleachery washing stages of similar pH. Excess water discharged from the washers constitute the bleachery effluent
The largest quantity of unwanted material is dissolved from the pulp in the prebleaching C and E-stages. It is from
these two stages that the vast majority of dioxins and furans as well as other chlorinated organics are discharged. The
C-stage consists of treatment of the pulp slurry with elemental chlorine, or combinations of chlorine dioxide and
elemental chlorine . The slurry consistency is normally in the range of three% and, depending upon the lignin
content of the brownstock pulp, the chlorine charge may range from 70 to more than 200 Ibs/ton for softwood pulps
and from 25 to more than 100 Ibs/ton for hardwood pulps. The temperature in the C-stage is usually 15 to 30° C,
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White liquor
*
Wood
Barking
drum
To recovery •*
and tall oil Black
production liquof
Bleaching
Fintr
pulp
:h*d —
<
^
Chk
hd
xin*
••
*OT
dioxide tower
> D,stag*
^
•
A
y
Ikali
*••
towtr
E2 stag*
^^
ChK
hd
jrine
ta«
dioxide tower
0, stage
^^
Hyp
nc
ochk
^^
xit
^•B
e
tower
H stage
w^
Al
ZT
kali
«^
tower
E, stage
Bl*ach*ry *fflu*nt
FIGURE II-l KRAFT PULP MILL, INCLUDING A CONVENTIONAL BLEACH PLANT131
and the final pH is in the range of 1.5 to 2.0 s.u..92-126 The amount of chlorine and chlorine dioxide required in
prebleaching is directly related to the lignin content of the incoming pub).
TABLE II-l
BLEACHING SYMBOLS
SYMBOL
C chlorine [Cy
D chlorine dioxide [C1O2]
E alkaline extraction [NaOH]
H hypochlorite [NaOCl or Ca(OCl)2]
L hypochlorous acid [HC1O]
O oxygen [O2]
N nitrogen dioxide [NO2]
P peroxide [HjOj or NajOJ
Y hydrosulphite [Na2Sp4 or ZnS2O4)
Z ozone [O3]
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The E stage is an extraction of the chlorinated pulp with alkali, usually sodium hydroxide. More recent practice is to
add oxygen to the E-stage to enhance lignin removal thus reducing the amount of bleach chemical needed in
subsequent stages. The consistency in the E-stage is usually raised to more than 10% by removing water from the
chlorinated pulp prior to extraction. The reaction temperature is raised to 55 to 70° C and the final pH is about 11
s.u~92 In subsequent final bleaching stages, less aggressive treatments are used to achieve desired final pulp
brightness required for specific end uses.
During conventional bleaching of softwood kraft pulp, about 170 Ibs/ton of material is dissolved into bleaching
liquors. About 120 Ibs/ton originates from the residual lignin; about 46 Ibs/ton comes from the polysaccharide
fraction; and about 5 Ibs/ton is from the extractives portion of the pulp.92 About 75% of this material is dissolved
during the C and E stages.92
In pulp chlorination, chlorine reacts primarily with residual lignin in its molecular form. Oxidization, substitution
by chlorine, and the addition of hydrogen chloride are important reactions that lead to substantial depolymerization of
the lignin and to introduction of chlorine and various acidic groups into the lignin structure. As a result, part of the
residual lignin from pulping is dissolved in the chlorination liquor92
Reactions in the first caustic (alkali) extraction stage are less understood. In addition to ionizing the acidic groups
formed during the C-stage, which facilitates solution of the chlorinated lignin, treatment with caustic causes a
substantial removal of organically bound chlorine from the pulp formed during chlorination.92
COMPOSITION OF SPENT BLEACHING LIQUORS
Table II-2 presents the distribution of organically bound chlorine compounds by molecular weight for both
chlorination (C) and caustic extraction (E) stages. These data indicate that about 70% of the organically bound
chlorine is present as relatively high molecular-mass material (M > 1,000) in spent chlorination stage liquor; and,
for E-stage liquors, about 95% of the organically bound chlorine falls in this class. Analyses indicate a major part of
the high molecular weight material consists of cross-linked aliphatic compounds that are probably unsaturated. The
high molecular weight compounds are probably biologically inactive because they cannot penetrate cell membranes
in living organisms. However, the high molecular weight compounds break down chemically or biologically to
form low molecular weight compounds which may have detrimental biological effects.92
About 30% of the organically bound chlorine in C-stage liquors and five% in extraction stage liquors is of low
relative molecular mass (M < 1,000). These compounds have been classified into acidic, phenolic, and neutral
compounds. Acidic compounds consist of fatty, hydroxy, dibasic, aromatic, and resin acids. The phenolic
compounds consist of chlorinated phenols, guaiacols, vanillins, and catechols from softwood pulp bleaching and
additionally chlorinated syringols and syringaldehydes from hardwood pulp bleaching. Chlorinated catechols occur
primarily in C-stage liquors, while most chlorinated guaiacols and vanillins are found in spent E-stage liquors.92-138
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Table H-2
SIZE DISTRIBUTION OF^ ORGANICALLY-BOUND CHLORINE
FROM BLEACHING SOFTWOOD KRAFT PULP"
Weight Percent
Spent ' Spent
Chlorination Liuor Extraction Liuor
< 1,000 30% 5%
1,000 - 10,000 50% 20%
10,000-25,000 10% 20%
> 25,000 10% 55%
These compounds are formed from residual lignin.92 The neutral fraction is composed primarily of methanol and
various hemicelluloses, with comparatively less chlorinated material The neutral chlorinated compounds include a
number of saturated and unsaturated hydrocarbons, aldehydes, ketones and esters as well as chlorinated benzene
derivatives and sulfur-containing compounds. Quantitatively, chlorinated acetones, chloroform, dichloromethane, and
1,1-dichloromethlysulfone predominate. The total quantity of chloroform and dichloromethane formed will be much
higher if the bleaching sequence includes a hypochlorite (H) bleaching stage. Not all of the relatively low molecular
mass compounds formed during bleaching have been identified! n Studies completed during the past few years have
demonstrated that chlorinated dibenzo-p-dioxins (CDDs) and chlorinated dibenzofurans (CDFs) are trace by-products
of chlorine bleaching of kraft pulps. The most prevalent CDDs and CDFs found were 2378-TCDD and 2378-TCDF,
respectively.138
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. REGULATION FOR CHLORINATED ORGANICS FROM PULP MILLS
Many countries of Western Europe [Austria, Denmark, Finland, Federal Republic of Germany(FRG), Norway and
Sweden] as well as Canada and the United States already have or are presently in the process of developing
regulations for the pulp and paper industry specifically dealing with the discharge of chlorinated organic
compounds.21
EUROPE
Protection of the environment between European countries takes place through various conventions, often named
after the city where the agreement was initially reached. Two of these conventions are the Helsinki-Convention and
the Paris-Convention each of which has recently proposed regulations for the pulp industry regarding the discharge of
chlorinated organics.21 The proposals of these conventions as well as regulations, goals or proposed regulations for
individual countries are as follows:
HELSINKI CONVENTION
Following a IS February 1988 meeting of the Ministers of the Environment of the Baltic Sea Area a proposal was
worked out that all new sulphite mills must meet immediately and all existing chemical pulp mills must meet
before the year 2000 the following emission standards:52-21
Bleached Kraft Mills 2.0 kg AOX/metric ton pulp
Bleached Sulphite Mills 1.0 kg AOX/metric ton pulp
PARIS CONVENTION
The most recent Paris Convention meeting was held in London on January 17-19,1989. At that meeting, Sweden
presented the following proposal aimed at the reduction of chlorinated substances from the production of bleached
pulp.52
1. As of January 1, 1994, the discharge of chlorinated organic substances should not, as an annual
average, exceed the following values for each Contraction party's total production of:
Softwood kraft pulp bleached with chlorine chemicals: 2 kg AOX/metric ton
Hardwood kraft pulp bleached with chlorine chemicals: 1 kg AOX/metric ton
Sulphite pulp bleached with chlorine chemicals: 1 kg AOX/metric ton
2. The annual average values for each mill should, as a minimum, be based on one analysis a month.
Analysis should be made on representative 24 hours, unsettled samples.
FEDERAL REPUBLIC OF GERMANY
The Federal Republic of Germany has recently passed new and revised emission standards which became effective on
January 1,1990. These regulation include an AOX standard of 1.0 kg/metric ton for sulphite pulp mill.21 The FRG
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no longer allows the operation of kraft pulp mills.105 It should also be noted that no elementary chlorine is used in
sulphite pulp bleaching in the FRG and generally oxygen delignification is utilized at these facilities.21
FINLAND
While Finland does not presently have regulations pertaining to the discharge of chlorinated organics, the
government has an official goal for AOX of 1.5-2.0 kg/metric ton.21 In 1989, the average treated effluent AOX
discharge for Finnish bleached kraft mills was 2.86 kg/metric ton and the industry expects to reduce that value to 1.4
kg/metric ton by 1995.21
NORWAY
Chlorinated organic effluent standards for bleached pulp in Norway are: AOX (Kraft): 2 kg/metric ton; and AOX
(Sulphite): 1 kg/metric ton.52
SWEDEN
Swedish regulations set out short term and long term requirement for the reduction of TOO discharged to receiving
waters. The short term requirement is 1.5 kg TOCl/metric ton to be achieved before the end of 1992.21 The long
term requirement is 0.1 kg TOCl/metric ton to be achieved before the end of 2010.21
CANADA
The Federal Government of Canada (Environment Canada) is currently in the process of developing regulations under
the 1988 Canadian Environmental Protection Act (CEPA) to control the discharge of persistent toxics such as CDDs
and CDFs.71 A control regulation for CDDs and CDFs will be promulgated by the middle of 1990, following
public consultation and ministerial review as required by law.71 In addition, consideration is now being made as to
what substances in addition to CDDs and CDFs should be controlled.71 Also, at least four Canadian Provinces are in
the process of establishment of regulations or issuing licenses dealing with the discharge of chlorinated organics.
These provinces are. Alberta, British Columbia, Ontario and Quebec.
ALBERTA
The Province has no regulations pertaining to AOX, however, all existing and new bleached kraft mills will be
licensed in the near future at 1.5 kg of AOX /metric ton (monthly average) and 1.4 kg of AOX/metric ton (monthly
average), respectively.
BRITISH COLUMBIA
The Provincial Government is in the process of issuing new guidelines which will contain among other things an
AOX limitation of 2.5 kg/metric ton by 1991 and 1.5 kg/metric ton by 1994.21 While these standards have not been
officially established, they are being incorporated into orders and permits and mills are designing systems to meets
the limits and the dates established.
-15-
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ONTARIO
In 1985, the Province of Ontario launched the MISA program (Municipal Industrial Strategy for Abatement) with
the goal of elimination of persistent toxic compounds from the waters of the Province.21-123 This program
specifically addressed kraft mill effluents and resulted in the development of the following goals:
TABLE 1II-1
LEVELS OF ACHIEVEMENT FOR ONTARIO KRAFT PULP AND PAPER MILL
EFFLUENTS21-123
Organochlorines,
Level kg AQX/ADMT
I (Present level for all mills without treatment) £5.0
n (Present level for mills with primary treatment) <4.5
m (Achieved within 1-3 years (1989-1991)) <2.5
IV (Achieved by 1993) " <1.5
It is expected that these recommendations will be finalized in regulation in 1991, however as in British Columbia,
companies are expected to institute programs now to meet the proposed limits.21
QUEBEC
An AOX limitation of 1.5 kg/tonne has been set by the Quebec Ministry of the Environment which is to be
achieved by 1993.193
UNITED STATES
Under the Clean Water Act Amendment of 1987, EPA is presently in the process of revising the effluent limitations
guidelines for the pulp and paper industry. The primary focus of this revision will be to develop Best Available
Technology (BAT) limitations for 2378-TCDD for the chlorine bleached chemical pulping subcategories. In addition
to 2378-TCDD, other toxic pollutants will be assessed and limitations established as appropriate. The present
schedule for promulgation of the revised BAT regulations is July 1995.
-16-
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in. MINIMIZATION OF CONTAMINATION FROM EXTERNAL SOURCES
WOOD SOURCES
A possible source of TCDD and TCDF in pulp mill effluents, sludges and pulps is from the use of contaminated
chips from sawmills where lumber has been treated with chlorophenols. This possible source of contamination has
not been specifically identified in U.S mills, however, it has been identified in several British Columbia mills.162 In
order to guard against this possible source of contamination, companies purchasing chips from unknown suppliers
should either require certification that the chips are not contaminated or should perform periodic monitoring to insure
that such contamination does not exist.
SELECTION AND USE OF ADDITIVES
Technology Description;
Numerous additives are used in the production of bleached pulp two groups of which have been shown to contain the
dioxin and furan precursors DBD and DBF. These two groups of additives include defoamers and pitch dispersants.
Defoamers are added to brownstock pulp slurries prior to pulp bleaching to prevent accumulation of entrained air
which can lead to formation of foam that can interfere with downstream processing. Defoamers are made of
kerosene, fatty acids, fatty alcohols and other hydrocarbons, or can be water-based Recent research by the Pulp and
Paper Research Institute of Canada (PAFRICAN) demonstrated that oil-based pulp mill additives, particularly
brownstock defoamers are potential sources of unchlorinated dibenzofuran (DBF) and dibenzo-p-dioxin (DBD) and can
result in elevated CDD and CDF levels in bleached kraft mill pulps.33-119 Similar studies were carried out by
\\festvaco researchers. They added various defoamers to unbleached pulps at three to five times normal application
rates resulting in elevated 2378-TCDD and 2378-TCDF levels in chlorinated pulps.108 Findings of unusually high
levels of 2378-TCDF at a number of mills in the 104 Mill Study have been linked to use of contaminated oil-based
defoamers. In some cases, the levels of 2378-TCDF found at these mills exceeded median values for all mills by
more than two orders of magnitude. The technology to address this problem is to switch to a non-contaminated
defbamer.
Pitch dispersants are added to the pulp prior to washing similar to brown stock defoamers. Generally these
dispersants are oil based. The majority of investigation work in the industry has been directed toward defoamers,
however, recently a number of facilities have identified pitch dispersants as sources of precursors and have therefore
either discontinued there use or found alternative agents which had lower levels of precursors.
Effectiveness:
Where changes have been made from contaminated to clean defoamers, the 2378-TCDF levels have been reduced to
levels well within those encountered at the majority of mills in the 104 Mill Study. The impact on formation of
2378-TCDD has been less dramatic. Studies,performed at Western Pulp in Canada showed an approximate 90%
-17-
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reduction in the content of TCDF in the pulp and the effluent when they switched from an oil based defoamer with a
DBF level ofJ9500 ppb^io a defoamer made with non-recycled oil and a DBF level"6f/<260~ppb!162 Studies
performed by James River on various defoamers revels that there can be a substantial difference between the level of
DBF in defoamers ranging from 11 to 2230 ppb.136 See Table IV-1.
TABLE IV-1
DIBENZOFURAN ANALYSIS OF DEFOAMERS13*
Sample Number MfltP^P ^d Description DBF fppb)
1 CZ 7921 yr. composite 1988 66
2 CZ 7021 yr. composite 1988 350
3 CZ 710 HjO based; 1 yr. composite 1988 11
4 CZ 702 3 runs, 10/88 497
5 CZ 792 Batch 11/14/88 138
6 CZ 710 H£> based; batch 11/15/89 1.7
7 Oil in tank 26 11/17/88 (Witco) 520
8 Oil in tank 32 11/17/88 (Witco) 539
9 Oil as delivered 11/21/88 (Witco) 2230
10 Oil as delivered 12/5./88 (Witco) 833
11 Oil as delivered 3/1/89 (Chevron) 128
12 Oil as delivered 3/20/89 (Chevron) 32
13 Sample 12 spiked with 50 ppb DBF 72
While this research has led to the reduction of CDD and CDF being discharged by the industry, recent research
indicates that precursors other than DBD and DBF for CDDs and CDFs exist10*
Installations:
Numerous mills have made the conversion to low precursor additives as evidenced by recent submissions made to the
Agency relating changes made since samples were obtained for the 104 Mill Study.
Implementation:
inasmuch as no significant process modifications or equipment changes are necessary, the implementation time to
change from contaminated to clean additives should not exceed the time necessary for purchase and delivery of
replacement chemicals.
-18-
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Costs:
The literature contains no information regarding the cost of clean vs. contaminated additives. However, it is not
thought that the the conversion to clean additives would result in a significant cost impact
References:
33,108, 119, 136, 141, 189
-19-
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V. MINIMIZATION ON CONTAMINATION THROUGH PROCESS CHANGES
PULPING
AVAILABLE TECHNOLOGIES
EXTENDED DELIGNIFICATION
Technology Description!
This technology involves extending the kraft cooking process to produce a brownstock pulp with lower lignin
content, thus reducing the demand for bleaching chemicals. Extended cooking involves modifying the process to
obtain a more even alkali profile through the digesters, combined with partial countercurrent operation.16 The pulp
is digested longer either in continuous or batch modes, with modified time-temperature-alkaline cycles to reduce
adverse impacts of extended pulping on pulp quality. As of the present date, the two most used extended
delignifications systems are Modified Continuous Cook and Rapid Displacement Heating.
The Modified Continuous Cook (MCC) process was developed by Kamyr for more selective removal of lignin in
continuous digesters. The process is based on principles developed by STFI in the late 1970's which include low
effective alkali concentrations at the beginning of the cook and low concentrations of lignin at the end of the cook.
This is accomplished by splitting the addition of the cooking liquor such that fresh liquor is introduced near the end
of the cooking cycle and is circulated counter-currently to the chip flow, to maintain alkalinity. Using this process,
the kappa number of unbleached pulp can be reduced from 30-32 for conventional cooking to 22-25 for softwood and
from the conventional cooking of 16-18 to 12-14 for hardwood.121
Rapid Displacement Heating (RDH) is a low energy cooking process for batch digesters developed by Beloit
Corporation. In RDH, liquor profile chemistry is controlled to subject the incoming wood chips first to recycled
black liquors which neutralize the acidity of the incoming wood. In this stage, the more soluble fractions of the
extractives, lignin, and oligomeric hemicelluloses are dissolved and removed. This accounts for a net lower alkali
charge during the high temperature portion of the RDH cook, which in turn results in improved strength and other
pulp characteristics. Softwood brownstock kappa numbers as low as 15-18 and hardwood kappa numbers as low as
8-10 can be attained with this process without hardware modifications.12
Effectiveness:
Reduced consumption of active chlorine following extended delignification has been documented in pilot tests and at
full scale.6*16 Given that the amount of chlorine required in prebleaching is directly related to the lignin content of
the brownstock pulp, any process that results in incremental lignin removal prior to bleaching will result in reduced
quantities of chlorinated organics formed. A comparison of untreated effluent from a bleached kraft mill for different
combinations of process controls including extended delignification is provided in TABLE V-1.
-20-
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TABLE V-l
CHARACTERISTICS OF UNTREATED EFFLUENT
FROM A BLEACHED SOFTWOOD KRAFT PULP MILL
SHOWS ADDITIVE EFFECTS FOR DIFFERENT IN-
PROCESS MODIFICATIONS1"
Flow, m3/a.d.m.ton
BOD5, kg/a.d.m.ton
COD, kg/a.d.m.ton
Color, kg/a.d.m.ton
AOX, kg/a.d.m.ton
CASE A
50-55
28
100
300
7.9
CASES
50-55
22
70
100
4.7
CASE C
50-55
20
55
80
3.6
CASED
50-55
20
55
65
1.9
Case A is state-of-the-art kraft mill employing conventional process technology.
Case B is Case A with oxygen delignification.
Case C is Case B with modified cooking (extended delignification).
Case D is Case C with 70% chlorine dioxide substitution.
This comparison shows that extended delignification is effective in removing chlorinated organics, measured as
AOX, as well as other pollutants of concern. Another study showed that formation of TOC1 is reduced from 6-7
kg/ton of pulp to 4.5-5 kg/ton of pulp with extended delignification.22
In addition to the effluent reduction benefits, RDH pulping is reported to result in up to a ten percent increase in
pulp strength; a 10-15% reduction in pulping cycle time; a 65% reduction in steam demand; and a two to three
GJ/ADMT energy savings.12>152 Extended delignification has the added benefit of affecting additional lignin removal
with recoverable pulping chemicals as opposed to consumable chemicals used in conventional bleaching.
Installations:
The number of extended delignification installations is growing rapidly. Reference lists for facilities where MCC and
RDH installations are planned, under construction or in operation are provided in Table V-2 and Table V-3,
respectively.
Implementation!
Extended delignification is compatible with conventional processes. Pulp quality is reported to be generally equal to
or better than conventionally cooked pulp. Reduced pulp yield and viscosity have been reported to be associated with
kappa number reduction; however, a gain in viscosity has also been reported.6-16 Retrofitting existing batch
-21-
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TABLE V-2
WORLDWIDE EXTENDED DELIGNIFICATION - MODIFIED CONTINUOUS COOK
(MCC) REFERENCE LIST*
Enso-Gutzeit OY
Metsa-Botnia AB, OY
Consolidated Papers Inc.
Domtarlnc.
Alicelb
Federal Paper Board Co., Inc.
AB Iggesunds Bruk
KemiOY
Longview Fibre Company
KorsnasAB
Oji Seishi
Champion International Corp.
Tasman Pulp and Paper LTD
AB Iggesunds Bruk
Howe Sound Pulp and Paper LTD
Federal Paper Board Co., Inc.
Daishowa Canadab
Weyerhaeuser Company
Aracruz6
Stone Container Corp.
BahiaSulb
Union Camp Corporation15
Champion International Corp.
LOCATION
Varkaus, Finland
Aanekoski, Finland
Wisconsin Rapids, WI
Windsor,xQue.
Alizay, France
Augusta, GA
Iggesund, Sweden
Kemi, Finland
Longview, WA
Gavle, Sweden
Kasugai, Japan
Hinton, Alta.
New Zealand
Iggesund, Sweden
Port Mellon, B.C.
Augusta, GA
Peace River, Alta.
Columbus, MS
Aracruz, Brazil
PL Wentworth, GA
Entre Rios, Brazil
Eastover, SC
Courtland,AL
PRODUCTION
TPD
450
1210
400
1145
900
770
690
880
1060
1160
880
1460
550
700
1450
1520
1360
. 1575
2075
865
1500
1250
1180
FURNISH
HWD/SWD
HWD/SWD
HWD/SWD
HWD/SWD
HWD
HWD/SWD
SWD
HWD/SWD
SWD
HWD/SWD
SWD
SWD
SWD
HWD
SWD
HWD
HWD/SWD
HWD/SWD
HWD
HWD
HWD
HWD
SWD
START-UP
1983
1987
1987
1987
1987
1987
1988
1988
1988
1989
1989
1989
1989
1989
1990
1990
1990
1990
1990
1991
1991
1991
1991
• Source: Kamyr, Inc.
b Future Provision
digestion systems with extended delignification would require enough additional space for the installation of a tank
farm. To date, the majority of RDH digesters in operation have been retrofits. Retrofitting an existing continuous
digester with MCC, however, is not as feasible. Of some 180 continuous digesters in North America, less than ten
could be retrofitted with MCC according to the supplier.137
-22-
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TABLE V-3
WORLDWIDE EXTENDED DELIGNIFICATION - RAPID DISPLACEMENT HEATING (RDH)
REFERENCE LIST8
START-UP MTT.L/LnCATlQN
1985 Joutseno Pulp
Joutseno
Finland
1987 Nymolla AB
Nymolla
Sweden
1988 S.D. Warren
Afcstbrook, ME
USA
1989 Bowaters Southern Paper
Calhoun, TN
USA
1989 Fletcher Challenge
Crofton. B.C.
Canada
1990 Chung Hwa Paper Corp.
System I
Hualien, Taiwan
1990 Willamette Industries
Bennettsville, SC
USA
1990 Chung H wa Paper Corp.
System n
Hualien, Taiwan
DIGESTFJtS
PRODUCTION
4New-200m3-SSClad 950 ADT/D
7 Retrofit -• 140 m3 - Mild Steel
4 Retrofit - 380 m3 - Solid SS 860 ADT/D
5 Retrofit - 250 m3 - Solid SS
4 New - 200 m3 - SS Clad 450 ADT/D
8New-200m3-SSClad 1200 ADT/D
8 Retrofit -168 m3 - SS Overlay 850 ADT/D
5 Retrofit - 120 m3
500 ADT/D
6 New-200m3-Mild Steel 860 ADT/D
with SS Nozzles
5 Retrofit - 120 m3
500 ADT/D
PULP
Bleachable Grades
Kappa Range 20 - 32
Softwood & Hardwood
MG - Sulfite Paper Grade
Softwood
Bleachable Grades
Kappa Range 8 -10
Hardwood
Bleachable Grades
Kappa Range 18-30
Softwood & Hardwood
Bleachable Grades
Kappa Range 26 - 30
Softwood
Bleachable Grades
Kappa Range 16-24
Mixed Tropical Hardwood
Bleachable Grades
Kappa Range 16-24
Softwood & Hardwood
Bleachable Grades
Kappa Range 16 -24
Mixes Tropical Hardwood
a Source: Beloit Corporation
Implementation time for a MCC system was provided by the supplier to be approximately 24 months from the order
date to start-up.137 Implementation time for a RDH system was provided by the supplier to be approximately 16
months for design, construction and installation.153 Present delivery time for the long lead items for RDH is
running around one year.153
-23-
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Costs;
For a new MCC digester (1200 ADST/day) the equipment cost would be $15 to $16 million with the installed cost
being $30 to $32 million.137 Of this cost, about $1.5 to $2.0 million would be related to the MCC portion.137
Retrofit costs for MCC are not appropriated as discussed above. No operating costs were found for the MCC
process.
For RDM systems, the capital cost would be approximately $1.5 million for each digester plus $5 million for the
tank farm with a turnkey cost being approximately three times as much.153 For a retrofit system, the only difference
would be in the cost of the digester which at the present date was estimated to be $600,000 for a 700 cubic foot
stainless steel clad digester.153 With respect to operation and maintenance costs, the supplier of RDM systems state
that the system has an 18 month payback based on steam savings, a better quality pulp, less evaporation required due
to higher solids in the washwater and a reduction (approximately 50%) in bleaching chemicals.153
References:
6, 12, 21, 42, 54, 72, 73, 85, 87, 89, 95, 96, 106, 109, 110,114, 116,121, 132, 137, 139, 144, 152, 153, 166,
173, 178, 181,182
-24-
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OXYGEN DELIGNIFICATION
Technology Description;
Oxygen delignification (OD), also referred to as oxygen bleaching, developed into a commercially feasible process in
the late 1960s and early 1970s. The first installation of OD was in South Africa, however, until recently, the
majority of installations have been in Sweden where oxygen delignification has been utilized as an economical
alternative to secondary treatment, and in Japan, where oxygen costs are low. Oxygen delignification is a pulp
treatment stage following final brownstock washing, but prior to bleaching with chlorine or chlorine derivatives. In
the process, brownstock pulp is treated with oxygen under pressure in an alkaline environment to remove additional
lignin and to alter other color producing material. Although oxygen delignification systems are often co-located with
bleacheries, they are chemically linked to the digestion process in that washwaters from OD stages are returned to the
chemical recovery system along with waste cooking liquor for recovery of inorganic chemicals and heat value from
the organic load removed from the pulp. This removal of organic load accomplished in OD reduces the downstream
chemical requirements for pulp bleaching, and attendant formation of chlorinated organics.22
Oxygen delignification was originally developed as a high consistency (25-28%) process, however with the
development of the high shear mixer, medium consistency (10-12%) operation became feasible.8 Consistency
selection is dependent on capital cost, the degree of delignification and steam, alkali and power consumption. High
consistency systems are slightly higher in cost than medium consistency systems due to the need for a pulp press
prior to the reactor.8 Delignification in the two systems is comparable with the high consistency systems running
in the range of 45-50% as compared to medium consistency systems which run in the range of 40-45%. * Steam and
alkali consumption are higher in the medium consistency systems whereas power consumption is higher in high
consistency systems.8
OD is compatible with other new technologies aimed at reducing bleach plant effluents and OD bleached pulps are
reported to be equal or superior to conventionally bleached pulps with respect to tear strength, brightness stability,
pitch removal, beating energy and cleanliness.8>7S Because approximately one-half of the original residual lignin is
removed during the oxygen stage, the number of subsequent conventional bleaching stages may be reduced. It is
now well-established commercially that for bleached softwood kraft pulp, a four-stage sequence such as C/DEHD
following oxygen delignification is sufficient to attain 90+ GE brightness, and that a three-stage sequence such as
CED is adequate to achieve an 85 to 90 GE brightness level.75
Effectiveness!
The environmental benefits associated with OD have been documented in many publications. These benefits accrue
from two facts. The first is that by reducing the amount of lignin carried forward with the pulp, levels of BOD,
COD and color are reduced in the effluent discharged This reduction has been reported to be 40-55% for BOD, 45-
55% for COD and 60-75% for color.8 Secondly an oxygen delignification stage placed ahead of chlorination reduces
-25-
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the amount of chlorine conventionally required by about 50% and reduces the amount of chlorine dioxide required for
a given brightness, resulting in a reduction in the amount of chlorinated organics discharges.38-57 A review of Ta b le
V-1 presented earlier shows that OD reduces AOX levels from 7.9 kg/ADMT to 4.7 kg/ADMT (41% reduction).121
Another study shows that TOO formation from a kraft softwood pulp bleach plant was reduced from 5 to 5.5
kg/metric ton of pulp to 2.5 to 3.5 kg/metric ton of pulp (35-50%).58 A third study reported a reduction in total
organic chloride from 5.4 kg /ton of pulp using a D(30)/C(70)EDED sequence to 0.7 kg /ton of pulp using a
ODEoD sequence, for bleaching softwood Kraft pulp.61
Use of OD systems has not completely eliminated formation of 2378-TCDD and 2378-TCDF, but at three U.S.
mills using OD systems levels found tend to be in the lower range of values encountered at U.S. mills. CDD and
CDF data from three mills with oxygen delignification are provided in Table V- 4. The CDD and CDF levels for
most of the effluents and pulp sampled were below the detection level.
Additional data related to oxygen delignification in combination with other processes such as chlorine dioxide
substitution will be presented in subsequent sections.
Installations:
According to a recent article, oxygen delignification systems corresponding to approximately one third of the world
bleached kraft pulp production have now been sold.196 The first OD installation was started up at the SAPPI mill in
South Africa in 1970. Since that date, the world's annual production capacity has steadily increased. A November
1987 TAPPI Journal article reported that since 1970, there have been 44 oxygen delignification process startups with
a 1988 anticipated annual production capacity in excess of 10 million metric tons per year.8 The same article broke
down the production as of that date as 92% kraft, 60% softwood, 60% high consistency, 50% in Scandinavia and
Europe, 20% in North America and 20% in Japan.8 To illustrate the extant to which OD has been implemented in
Sweden, production and process data are presented in Table V- 5. From this table it can be seen that at the present
date 86% of Swedish permitted bleached kraft production is subjected to oxygen delignification and that by the end of
1990 it will be 88%.
Those facilities that are presently planned, under construction or in operation are presented in Table V- 6. A review
of this listing shows that the 1990 anticipated annual production capacity will be in excess of 14 million metric tons
per year, that the majority of production is still kraft softwood, the majority of new installations are in North
America and that since about 1984, the vast majority of installations are based on medium consistency.
Implementation;
Compatibility With/Impact on Pulp and Other Processes
Several authors have compared conventional bleaching processes with a process having an oxygen delignification
stage. Impacts on pulp and processes presented in the literature include those related to the recovery system,
chemical make up and usage, product quality, process control and compatibility. Routing the wash water from the
-26-
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TABLE V-4
DIOXIN/FURAN DATA FOR THREE
BLEACHED KRAFT MILLS WITH OXYGEN DELIGNIFICATION"1
WOOD TYPE (LINE1)
(LOSE 2)
OXYGEN DELIGNIFICATION (LINE 1)
(LINE 2)
DIOXINS & FURANS
BLEACHED PULP (LINE 1)
2378-TCDD, ng/1
2378-TCDF, ng/1
BLEACHED PULP (LINE 2)
2378-TCDD, ng/1
2378-TCDF, ng/1
Eo FILTRATE (LINE 1)
2378-TCDD, pg/1
2378-TCDF, pg/1
Eo FILTRATE (LINE 2)
2378-TCDD, pg/1
2378-TCDF, pg/1
WASTEWATER INFLUENT
2378-TCDD, pg/1
2378-TCDF, pg/1
FINAL EFFLUENT
2378-TCDD, pg/1
2378-TCDF, pg/1
MTTT. 1
SWD
YES
ND(1.5)
NQ(14)
ND(8)
ND(13)
ND(8)
ND(8)
ND(10)
ND(10)
MTU. 2
SWD
HWD
YES
YES
ND(0.8)
2.11
ND(1.0)
ND(1.2)
102
114
ND0)
ND(3)
ND(4)
NCK7)
NCK2)
ND(12)
MILL 3
HWD
HWD
NO
YES
ND(0.4)
2.71
ND(0.7)
ND(0.6)
ND(5)
95
ND(5)
42
ND(3)
ND(4)
ND(8)
ND(8)
oxygen delignificadon process to the recovery system increases the solids load to the chemical recovery furnace,
typically by 3-5% and up to 10% if existing brownstock washing is not efficient.Si31'75 Although recovery of these
dissolved solids and lignin contribute to steam generation, the capability of existing recovery furnaces to accept the
additional solids loading is uncertain. Possible solutions for those cases where recovery furnaces could not accept
additional solids loading would be through the use of anthraquinone and/or polysulfide pulping which is covered in
more detail in subsequent sections of this report.158 Installation of an oxygen stage into an existing conventional
system would require caustic for the oxygen stage which is usually met through use of oxidized white liquor. This
results in an increased load on the causticizing plant and lime kiln on the order of 3-5% and increasing evaporation
-27-
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steam requirements on the order of 0-4% for high consistency and 4-10% for medium consistency oxygen
bleaching;*'57 While the oxygen delignification process requires a source of caustic, chemical usage (primarily
chlorine and caustic) across the entire facility would be reduced.* Oxygen bleaching has a superior ability to decrease
shive content and the oxygen bleaching stage is less sensitive (than conventional stages) to kappa number changes in
the incoming pulp allowing the control of kappa number within narrow limits.75 Oxygen bleaching is compatible
with other chlorine-free bleaching processes being developed75
TABLE V-5
EXTENDED DELIGNIFICATION, OXYGEN DELIGNIFICATION
AND BIOLOGICAL WASTEWATER TREATMENT AT
SWEDISH BLEACHED KRAFT PULP MILLS1"
MAXIMUM ALLOWED PRODUCTION, 1000 METRIC TONS/YEAR
EXTEN.
TOTAL SOFTWOOD HARDWOOD DELIG.
100
345
108
AspaBruk
Gruvon
Husum
Iggesund1
Karlsborg
Korsnas
Monsteras
Morrum
Norrsundet
Skoghall
Skutskar
Skarblacka
Vallvik
Varo
Ostrand
TOTALS
%
115
310
690
325
290
325
350
375
252
110
500
150
220
300
322
4,634
100
115
210
345
217
290
244
175
150
252
110
360
b
220
300
232
325
290
325
81
175
225
140
- 300
90
1,240
27
1 Oxygen delignification on both lines to be operational in 1990.
b No decision regarding production split between softwood and hardwood.
OXYGEN
DELIG.
115
310
690
217
-
325
350
375
252
-
360
150
220
300
322
3,986
86
BIO.
TREAT.
-
310
-
325
290
325
350
-
-
110
-
150
-
-
-
1,860
40
ED+OD
+BIO.
-
-
-
217
-
325
-
-
-
-
-
-
-
-
-
542
12
-28-
-------
TABLE V-6
WORLDWIDE OXYGEN DELIGNIFICATION REFERENCE LIST*
COMPANY
Alberta Pacific
ASSI Karlsborg
BillerudAB
Bowaters-Southem
Canadian Forest Products
Celgar Pulp Company
Cellulose d'Aquitaine
Cellulose des Ardennes
CELPAG
Celulosa Arauco
Celulosa del Pacifico SA
Champion International
Champion International
Champion International
Champion International
Champion International
Champion International
Chesapeake
Chuetsu Pulp Ind Co., LTD
Chung Hwa Pulp Corp.
Chung Hwa Pulp Corp.
Consolidated Paper
Daishowa
Daishowa
Daishowa
Daishowa
Eddy Forest Products
Eddy Forest Products
Empresa National deCelulosas
Fiskeby AB
Hokuetsu Paper
Hokuetsu Paper
Howe Sound P.& P., LTD
Iggesunds Bruk AB
International Paper Company
James River-Marathon, LTD
Jujo Paper
Jujo Paper
KemiOY
Kishu Paper
Korsnas AB
Korsnas AB
Louisiana-Pacific Corp.
Mitsubishi
Mitsubishi
MoDoCell AB
Munksjo AB
NCB Vallvik
CONSIS- BLEACH
LOCATION OQUNTRY ADMT/D WOOD TENCY SEQUENCE
Athabasca, ALB
Karlsborg
Gruvon
Calhoun.TN
Pr. George, BC
Castelgar, BC.
St-Gaudens
Rouvroy
Ribeirau Preto
Arauco
Mininco
Canton, NC
Courtland AL
Hinton, ALB
Pensacola, FL
Pensacola, FL
Quinnesec, MI
West Point, VA
Sendai
Hualien Hsien
Hualien Hsien
Wise. Rapids, WI
Shiraoi
Shiraoi
Suzukawa
Peace River, ALB
Espanola, ONT
Espanola, ONT
Huelva
Skarblacka
Niigata
Niigata
Port Mellon, BC
Iggesund
Texarkana, TX
Marathon, ONT
Kushiro
Yatsushiro
Kemi
Shiraoi
Gavle
Marmaverken
Eureka, CA
Hachinohe
Shirakawa
Husum
Aspa
Vallvik
KRA
Canada
Sweden
Sweden
USA
Canada
Canada
France
Belgium
Brazil
Chile
Chile
USA
USA
Canada
USA
USA
USA
USA
Japan
Taiwan
Taiwan
USA
Japan
Japan
Japan
Canada
Canada
Canada
Spain
Sweden
Japan
Japan
Canada
Sweden
USA
Canada
Japan
Japan
Finland
Japan
Sweden
Sweden
USA
Japan
Japan
Sweden
Sweden
Sweden
1400
1025
500
1180
1320
500
520
500
750
1050
1600
1150
1300
560
730
1150
550
550
445
445
450
550
400
620
960
500
500
965
510
480
600
1000
900
600
550
1055
530
1050
100
680
1100
300
1000
380
600
SWD/HWD
SWD
SWD
SWD/HWD
HWD
HWD
SWD
SWD/HWD
SWD
SWD
HWD
HWD
HWD/SWD
HWD
HWD
HWD
HWD
SWD
SWD
HWD
HWD
HWD/SWD
HWD
HWD
SWD
HWD/SWD
Med
Med
High
Med.
Med.
High
Med.
High
Med.
Med.
Med.
Med.
Med.
Med.
Med
Med.
High
Med
Med
Med
Med
High
Med.
Med
Med
High
High
Med
Med
Med
Med
Med
Med
Med
SWD High
HWD Med
Med.
HWD Med
HWD/SWD Med
Med
SWD Med.
HWD Med
HWD Med
SWD High
SWD High
SWD High
OC/DEDED
OC/DEoD
OCEDED
OC/DEoD
OC/DEoD
OC/DEoD
C/DOD
OCHpHEpD
OC/DEoD
OCEHD
OC/DEoHD
OC/DEHD
OC/DEoD
OCEHD
OD/CEopDEpD
OH
OCEHD
OC/DEoDD
OC/DEoDED
OC/DEDED
OC/DEDED
OC/DEDED
START
DATE
1992
1990b
1972
1990
1992
1973
1985
1979
1989b
1989b
1992
1991
1987
1987
1986
1990
1972
1986
1987
1987
1980
1975
1986
1986
1990
1977
1980
1986
1986
1988b
1990
1990
1975
1989
1989b
1987
1987
1983
1989
1988b
1986
1977
1973
1978
-29-
-------
TABLE V-6 (CON'T)
WORLDWIDE OXYGEN DELIGNIFICATION REFERENCE LIST*
COMPANY
New Zealand Forest Prods.
Norrsundet Bruks AB
Oji Paper
Oji Paper
OYSchauman
Polser Zellstoff
Pope & Talbot Pulp Co.
Pon Westward Pulp
Potlatch Corporation
Procter & Gamble
Proctor & Gamble
PT Indah Kiat Pulp & Paper
Repap Manitoba Inc.
Sanyo-Kokosaku Pulp Co.
Sappi
Sappi
Sappi
SCAPulpAB
Simpson Paper Company
Sodra Skogsagama AB
Sodra Skogsagama AB
Sodra Skogsagama AB
Sodra Skogsagama AB
Stora Cell AB
Stora Cell AB
Suzano de Papel e Celulose
Taio Seishi Paper
Taio Seishi Paper
Union Camp Corporation
Union Camp Corporation
Union Camp Corporation
Ustllimsk
V/O Prommash
\\feyerhaeuser Company
Willamette Industries
XinHua Paper Mill
Zaklady Celulozowo
Bayrische Zellstoff
Flambeau Paper
Hatmoversche Papierfabriken
Hunsfos
Industrias Forestales SA
PWAWaldhof
Rauma-Repola
Severomoravske Celulozky NP
Tofte Industrier
\teyerhaeuser Company
CONSIS-
LOCATtON
Kinleith
Norrsundet
Ebetsu
Tomakomai
Jakobstad
Pols
Halsey, OR
PL Westward, OR
Lewiston, ID
Oglethorpe, GA
Gr. Prairie, ALB
Perawang
The Pas, MAN .
Iwakuni
Enstra
Enstra
Ngodwana
Ostrand
Fairhaven, CA
Monsteras
Morrum
Morrum
Varobacka
Skutskaer
Skutskaer
Suzano
Mishima
Mishima
Eastover, SC
Eastover, SC
Franklin, VA
Ust nimsk
Svetogorsk
Columbus. MS
Bermettsville, SC
Shanghai
Kwidzyn
COUNTRY
New Zealand
Sweden
Japan
Japan
Finland
Austria
USA
USA
USA
USA
Canada
Indonesia
Canada
Japan
S.Africa
S.Africa
S.Africa
Sweden
USA
Sweden
Sweden
Sweden
Sweden
Sweden
Sweden
Brazil
Japan
Japan
USA
USA
USA
USSR
USSR
USA
USA
China
Poland
ADMT/D
750
1000
650
550
900
630
750
1000
1000
525
1200
450
200
500
575
1000
600
1000
420
700
950
650
650
1365
525
665
650
1100
800
800
455
1200
760
75
600
WOOD
HWD/SWD
HWD/SWD
SWD
SWD
SWD
SWD
SWD
SWD
SWD
HWD
SWD
HWD
SWD
HWD/SWD
SWD
HWD/SWD
SWD
HWD
SWD
SWD
SWD
HWD
SWD
HWD
HWD/SWD
HWD
SWD
HWD
SWD/HWD
Straw
SWD
TENCY
Med.
High
Med.
Med.
Med.
Med.
Med.
High
High
Med.
Med.
Med.
Med.
High
High
High
High
Med.
High
Med.
Med.
Med.
High
High
Med.
Med.
Med
High
Med.
High
High
Med.
Med.
Med.
Med.
High
BLEACH
SEQUENCE
OC/DEoOd
OD/CEHD
OH
OD/CEDED
OC/DEoDD
OC/DEoD
OD/CEoD
ODED
ODED
OD/CED
OC/DEDED
OC/DEDED
OC/DEDED
OC/DEDED
OCEHDD
OD/CEoHED
OC/DED
OC/DED
OQCEHDED
ODEDED
OC/DEoDD
OC/DEoD
OC/DEHD
START
DATE
1989b
1983
1986
1985
1987
1984
1991
1980
1991
1988b
1988b
1970
1978
1985
1980
1989
1981
1989
1989
1985
1977
1978
1989
1986
1984
1984
1989b
1981
1979
1985
1990
1990
1988b
1978
SULFITE
Kelheim
Park Falls, WI
Alfeld-Gronau
Hunsfos
Nacimento
Mannheim
Rauma
Paskov
Tofte
Cosmopolis, WA
FRG
USA
FRG
Norway
Chile
FRG
Finland
Czech.
Norway
USA
160
200
250
130
750
185
450
660
700
400
SWD
HWD
SWD
HWD/SWD
•
SWD
SWD
SWD
SWD
HWD/SWD
High
Med.
Med.
High
Med.
Med.
Med.
High
Med.
Med.
OEDH
OH
OCEH
OCEHH
POsPOaHH
OCEDH
1979
1987
1986
1979
1989b
1986
1983
1984
1983
1990
-30-
-------
TABLE V-6 (CON'T)
WORLDWIDE OXYGEN DELIGNIFICATION REFERENCE LIST*
CONSIS- BLEACH START
COMPANY LOCATION COUNTRY ADMTyP WOOD TENCY SEQUENCE DATE
SPECIALITY
KorsnasAB Gavle Sweden 100 HWD/SWD Med. 1983
M. Peterson & Son Moss Norway 150 SWD Med 1980
1 8, 116, 123, 137, 155, 157
b Order date
Availability
High consistency oxygen bleaching systems require that most of the equipment be fabricated from stainless steel to
avoid corrosion.75 Prices and work schedules could be affected by availability of stainless steel. One reference
claims that the stainless steel resource is very tight and that not even Asian sources, which are used by the industry,
can meet the demand.4 The majority of recent oxygen bleaching system installations have been medium consistency.
This trend has been influenced, to some degree, by the limited number of high consistency equipment suppliers in
certain geographic regions.8
Time to Implement
Implementation time will be highly site specific. Where recovery boiler capacity and space are not limiting factors,
installation of an OD stage to an existing bleach line can be accomplished in approximately two years. Information
obtained from a consulting firm related that six months were required for study with 20 months for installation.191
However, if major recovery system modifications are necessary, the implementation time for the total system could
take up to three years.
Limitations
Limitations identified in the literature are as follows: (a) Cellulose degradation. High consistency oxygen
delignification must be limited to approximately 50% of residual lignin in order to avoid excessive pulp strength
reduction;7' (b) Brightness. There is less of a margin than conventional CEDED process, in acquiring high
brightness (90% ISO) without deterioration in pulp strength.61 Brightness of 85-87 ISO can be achieved with short
sequence bleaching, however, one source reports that for high brightness pulp, 89-90 ISO, that five stages of
bleaching may be required.72 Another source reports that a pulp brightness of 90 ISO can be achieved on softwood
with OC/DE0D bleaching.57
-31-
-------
Costs:
The literature contains limited capital cost data for oxygen delignification systems. A large amount of data,
however, is available with respect to operational costs of OD systems especially as these costs compare to
conventional bleach systems.
Capital Costs
Capital costs for a bleaching sequence including an oxygen stage are reported to cost more than conventional
sequences, however, for a new mill these costs are offset by reduced capital costs for other processes such as
brownstock washing, chemical preparation, power boiler and effluent wastewater treatment facilities.57 One literature
source reported an installed capital cost of $8.8 million for a 500 ton/day OD system.73 This cost compares
favorably to a suppliers estimate of installed capital costs for a new SCO ton per day OD facility of $9-11 million and
for new 1000 ton per day facility of $14-16 million.m A second supplier related that the installed cost for a 1000
ADMT/day medium consistency OD facility would range from 80,000,000 to 100,000,000 SEK ($13-16
million).157 Another estimate of installed capital costs was obtained from a large consulting firm ranging from
$13.5 million for a hardwood medium consistency OD system to $19.5 million for a softwood high consistency OD
system.191 These costs, based on several installations are for a 600 air dried bleached tons per day facility and include
both pre and post washing in addition to the oxygen delignification system.191 In comparing system costs, it should
be pointed out that high consistency systems are more expensive than a similar sized medium consistency system
due to need for a pulp press costing in the range of $1-4 million.8 In addition to these estimated costs, costs for
three specific facilities are provided in TABLE V- 7.
TABLE V-7
OXYGEN DELIGNIFICATION CAPITAL COSTS*
PRODUCTION, CONSIS- CAPITAL COST,
COMPANY LOCATION ADMT/D TENCY $1000
Louisiana-Pacific Corporation Samoa, CA 680 Medium 8,000
Simpson Paper Company Fairhaven, CA 600 Medium 11,500
\VfeyerhaeuserCompany Cosmopolis, WA 400 Medium 9,000
Costs taken from news articles and information provided to EPA by the companies.
Operating Costs
Chemical savings associated with oxygen delignification are proportional to lignin reduction.31 Oxygen is the least
expensive chemical among the oxidizing agents used for the bleaching of pulps. In addition, the production of
oxygen requires one eighth the energy to make the chemically equivalent amount of chlorine.31
-32-
-------
Several references concur that when compared to a conventional sequence, a kraft softwood bleach line containing an
oxygen delignification stage would consume approximately the same amount of energy (steam and electricity),
consume less chemicals, and decrease wastewater treatment costs.5-11-57'76 Specifically, one source reported operating
cost savings of $16/ton of softwood pulp at 90 ISO brightness using high consistency OD and a bleaching sequence
of OC/DEoD vs. conventional C/DEDED bleaching.57 Another source reported annual cost savings of S8.55/ton for
softwood and $3.16/ton for hardwood.191 These figures agree fairly well with a third source which related cast
savings of $9 an $4/metric ton of softwood and hardwood pulp, respectively.'
After depreciating capital cost and incorporating operating and treatment costs savings, one source reports that the
use of oxygen bleaching in both an existing and a new plant results in a lower cost per ton of pulp.76 Using a
installed capital cost of $17 million for a 1000 ton/day facility and a operational cost savings of $9/ton results in a
return on equity of around seven years.
References!
3, 4, 5, 8, 10, 11, 14, 15, 21, 22, 23, 29, 31, 33, 36, 38, 40, 43,49, 55, 56, 57, 59, 60, 61, 63, 64, 65, 66, 69,
70, 72, 73, 74, 75, 76, 80, 83, 85, 90, 91, 92, 93, 95, 96, 98, 109, 112, 116; 120, 121, 132, 133, 140, 142, 144,
149, 155, 157, 158, 160, 165, 166, 168, 169, 170, 171, 173, 176, 177, 178, 184, 191, 196, 197
-33-
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POLYSULFIDE COOKING
Technoloffv Description:
Polysulfide cooking differs from conventional kraft cooking in the fact that the cooking liquor contains polysulfides.
Polysulfide cooking and its benefits have been know for many years. It was not until early in the 1970's, however,
when a practical concept was developed for the catalytic oxidation of white liquor that polysulfide cooking liquor
could be produced economically and without adverse environmental effects. Prior to this time, polysulfides were
produced by injection of sulfite into the white liquor which resulted in an increase of sulfidity and increased air
emissions. Two patented processes for catalytic oxidation of the white liquor are presently in use, one is the MOXY
process developed by Mead Corporation and the second is a new process developed by Mitsubishi and the Chiyoda
Corporation.158-159
Polysulfide cooking results in the ability to increase production yield at the same kappa number or to obtain the
same yield at a lower kappa number. The major advantage of the process, however, lies in the fact that through its
use less organic solids are produced in the black liquor resulting in a reduction in the load to the recovery boiler.158
This decreased load has been reported as 100-200 pounds of organics/ton of production, or an average of 6%.15S Use
of this process can therefore more than offset the additional load imposed by oxygen delignification, which typically
runs 2^%.8-158
Polysulfide cooking is also compatible with anthraquinone cooking which is discussed in a subsequent section.
Studies done at the Mitsubishi Shirakawa mill where both process are employed showed that the two process are
synergistic.158
Effectiveness:
The effectiveness of polysulfide cooking is directly tied to those for oxygen delignification. Use of polysulfide
cooking provides a means for mills that are recovery boiler limited to install oxygen delignification without the
purchase and installation of a new recovery boiler.
Installations;
This process is presently in use at six mills which are listed in Table V- 8.
Implementation;
The time required for installation from the date of order until start-up is reported to be 12 months.159
Costs:
The capital cost for installation of polysulfide cooking is reported to be $1.28, $1.85 and $2.23 million for a 500,
750 and 1,000 ADT/day mill, respectively.158 The incremental operation costs for the same sized mills are reported
to be $436,000, $642,000 and $822,000, respectively.1S8 Based on the increased production resulting from
-34-
-------
TABLE V-8
WORLDWIDE POLYSULFIDE COOKING REFERENCE LIST15*
COMPANY LOCATION START-UP DATE
M. Peterson & Sons Moss, Norway 1976
Sanyo-Kokusaku Pulp Company Yufutsu, Japan 1979
Hyogo Pulp Kogyo KK Tanigawa, Japan 1980
Zellstoff und Papierfabrik Frantschach AG St. Gertraud, Austria 1981
Mitsubishi Paper Mills LTD Shirakawa, Japan 1987
Mitsubishi Paper Mills LTD Hachinohe, Japan 1990
polysulfide cooking and the earnings associated with that production, the simple return on investment (ROI) for the
three alternatives is 7.2, 6.9 and 6.2 months, respectively.158 These operating costs and ROIs would be even less
according to the reference if polysulfide cooking were installed along with oxygen delignification.158
References:
158,159
-35-
-------
IMPROVED PULP WASHING
Technology Description:
The final stages of kraft pulping include a series of pulp screening and washing operations to remove black liquor
(spent pulping liquor) from the pulp prior to bleaching. The efficiency of the final washing stages is particularly
important with respect to consumption of chlorine in the bleach plant and formation of unwanted chlorinated
compounds. Excess black liquor increases the chlorine demand of the brownstock pulp and sends excess lignin and
associated breakdown products to the bleach plant These lignin breakdown products have been proposed by one
researcher as precursors to the dioxins and furans found in chlorinated pulps.10*
Within the past decade there has been much improvement made in the area of brownstock washing. Many equipment
options are now available including numerous pressure washers and pulp presses. The pressure washers operate at
feed consistencies ranging from 2-4%, are generally more compact in size, require less space for installation and
result in reduced effluent flows and energy savings.29'121. In addition to new technologies for the washing of
brownstock pulp, computer optimization programs are now available to assist operators in the selection of
washers.98
Effectiveness!
Not only do pressure washers results in reduced effluent flows and energy savings but studies have shown that the
amount of organic contaminants carried over to the bleach plant is decreased when the consistency of the pulp is
increased.85 Computer simulation studies have shown that with good washing, the carryover to the bleach plant
should be less than 10 kg/adt of COD and 5 to 8 kg/adt of dissolved solids measured as NajSO^12
Recent laboratory studies have shown that poor brownstock washing leads to increased levels of PCDDs and PCDFs
in softwood pulps.108 Results of these studies are shown in Table V- 9.
TABLE V-9
THE EFFECT OF BROWNSTOCK WASHING ON THE FORMATION OF
2378-TCDD IN PULPS1**
2378-TCDD (ppt)
POOR WASHING GOOD WASHING
C-StagePulp 7.3 3.3
E-Stage Pulp 6.3 2.1
Dl-Stage Pulp 8.1 2.5
D2-StagePulp 9.3 ND(4.2)
-36-
-------
During these studies the carryover of organics as measured by permanganate demand was 30% higher during poor
washing. In addition to these results, it was found that use of surfactants during brownstock washing reduced the
levels of PCDDs and PCDFs in the chlorinated pulp by 20-25% and that additional washing of the pulp prior to
chlorination with large amounts of 50% aqueous ethanol reduced the amount of chlorinated dioxins and furans in the
chlorinated pulp by 80%.108
Implementation!
Optimizing operation of existing washers can be accomplished in the short term (one to two months), subject to
possible delivery of replacement parts. Installation of replacement washers or new washing systems may require
several months to well over one year depending upon the scope of the project and equipment delivery. The new
generation pressure washers, however are smaller, require less space because they require no drop leg and come as an
assembled package, all of which should facilitate installation.
Costs:
Optimizing existing washing systems should require only minimal costs, and possibly could result in cost savings
through decreased use of bleach plant chemicals. Costs for new or replacement pressure washing systems were
estimated by one supplier to range from approximately $1 million for the smallest size to $1.8 million for the
largest size.112 The energy savings associated with pressure washers over drum washers were estimated by one
source to be $104,000/year based on 3.20/kwH, and 100-130 pounds of steam/ton of pulp by another 115>146
References:
8, 29, 51, 85, 98, 108, 112, 115, 121, 141, 146, 192, 196
-37-
-------
EMERGING TECHNOLOGIES
PRETREATMENT WITH NITROGEN DIOXIDE
Technology Description!
PRENOX* is a proprietary pulp pretreatment process developed by Olaf Samuelson and co-workers at the Chalmers
Institute of Technology in Sweden.10 The patent for this process is presently held by Sunds Defibrator AB,
Sundsvall, Sweden. The process consists of pretreatment of kraft pulp under acidic conditions with one to two
percent nitrogen dioxide (NO2) at medium to high consistency and moderate temperatures.9'10 This pretreatment is
normally carried out after digestion and before oxygen delignification. Duration of NO2 pretreatment ranged from 15
minutes to 120 minutes in pilot plant studies.10 This technology allows up to 80% lignin removal in the oxygen
stage which is normally limited to 50% by selectivity considerations.31
Effectiveness:
This pretreatment process has been extensively studied in the laboratory.31 The laboratory results prompted four
Swedish companies (AGA, Mo och Domsjo, Nobel Industries and Sunds Defibrator) to mutually finance a pilot
plant which was built at the SCA mill in Ostrand.10'36 Pilot studies have shown that delignification of 70 to 80% is
possible which corresponds to a kappa number of nine to ten being achieved on softwood.54'95 More recent studies
by Samuelson have shown that kappa numbers below five can be achieved.165 When followed by an oxygen
bleaching stage, this technology has demonstrated high potential to reduce TOCL from the paper making
process.9'10-22'31'42'55 A pilot plant study demonstrated that TOCL loads can be reduced from approximately 6 kg per
metric ton to 2 kg per metric ton for conventional bleach plants.22 When compared to conventional oxygen
delignification to kappa number 17, this pretreatment decreases the active chlorine required for 90% ISO brightness
by 55%.42 BOD7, COD and total organic chlorine (TOCL) decrease 55%, and color decreases 75%.42
Pretreatment with nitrogen followed by oxygen delignification results in kappa numbers below ten for softwood. A
combination of these processes followed by high chlorine dioxide(90%) resulted in TOO values of less than 0.5
kg/ton of pulp.54 This is a significant step toward the effluent limitation established by the Swedish government of
0.1 kg/ton to be achieved by the year 2010.
x
PRENOX also has an impact on aquatic toxicity of the wastewater effluent Studies reported by Norden showed that
when untreated PRENOX waste was tested that it showed lower aquatic toxicity for all species tested except
MICROTOX. However, after biological treatment the toxicity was lower for all organisms when compared to
unbleached and oxygen delignified pulps.195
The influence of PRENOX on chemical costs as well as on the quality of the effluent from a bleached kraft pulp mill
were presented by Norden and are shown in Table V-10.
-38-
-------
TABLE V-10
THE IMPACT OF PRENOX ON CHEMICAL COSTS AND EFFLUENTS'8
Kappa Number
C1O2 Substitution in 1st Stage
Chemical Cost, SEKb/t
COD, kg/t
AOX, kg/t
Chemical Prices:
UNBLEACHED
28
10 50
187
75
5.3
217
3.7
C12 1.20 SEK/kg
C102 2.60 SEK/kg
02 0.70 SEK/kg
NaOH 1.40 SEK/kg
18
40 50
176
49
2.3
179
2.0
PRENQX-O2
10
50
164
22
1.4
Installations:
At the present time there are no mills employing this technology, however, Sunds Defibrator AB is currently
looking for a Swedish mill at which to install a full scale demonstration facility. Two mills in Sweden have recently
installed two stage oxygen delignification systems to facilitate conversion to PRENOX at some future date if the
technology proves to result in lower AOX levels in the discharge then can be achieved with a two stage OD system.
Implementation:
Some of the concerns raised by the industry in Sweden relative to PRENOX are related to air emissions of NOX and
chemical availability. A trial bum done at the Norrsundet mill in Sweden showed that about five percent of the
nitrogen added to the recovery boiler would be emitted as NOx.95-195 This calculates to an increase in NOX
emissions by about 0.5 kilogram per ton of production.95 While it is unknown what problems exist with regard to
chemical availability in the U.S., the usual source of supply in Sweden for the NO2 was from fertilizer
manufacturers. Even through the pilot plant studies showed that there were no problems associated with regard to
the above concerns, industry remains skeptical and would like a full scale demonstration before proceeding.
The equipment required for PRENOX is similar to that for oxygen delignification. This being the case, the time for
implementation should be similar to that required for oxygen delignification, two to three years.
-39-
-------
Costs;
No cost information was found in the literature, however, capital costs should be similar to that for oxygen
delignification systems as discussed in a previous section of this report
References:
9, 10, 21, 22, 31, 36, 42, 54, 55, 95, 96, 165, 170, 173, 195
•40-
-------
DEMETHYLATION
Technology Descrintiom
Demethylation is a pulp pretreatment process that enhances delignification with peroxide and oxygen by creating
additional reaction sites in the pulp where delignification occurs. Demethylation of pulp is accomplished using
potassium thiophenoxide in diethylene glycol at 200°C.42
Effectiveness:
Laboratory studies have shown that demethylation followed by peroxide delignification can achieve a kappa number
of 7.S.42 This kappa number is typical of pulps entering the brightening stage. By enhancing pre-chlorination
delignification processes, chlorine consumption theoretically should be reduced, resulting in less formation of TOC1.
Installations!
At the present date there are no facilities utilizing this technology.
Implementation;
Due to the relatively severe conditions required for demethylation, a practical process for full scale application has
not yet been developed.42 No data was found discussing implementability.
Costs:
No data is available, due to the experimental nature of the process.
References;
42,59
•41-
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ANTHRAQUINONE CATALYSIS
Technology Description;
Anthraquinone (AQ) catalysis is a process modification in the cooking phase, involving addition of anthraquinone to
the alkali in a kraft cook. Anthraquinone is produced from coal tar from the coking process at steel mills. Through
the addition of anthraquinone the pulping process is accelerated, and the amount of lignin in the resulting unbleached
pulp is reduced.78
Effectiveness!
AQ catalysis has been well demonstrated in laboratory and pilot tests. The additional reduction of lignin prior to
bleaching lowers chlorine consumption, thus reducing formation of TOC1. BOD and color in the mill effluent are
also reduced.69
Installations;
Anthraquinone pulping is used at the Mitsubishi mill in Shirakawa, Japan.15*
Implementation:
Anthraquinone pulping results in higher production costs, however, as pollution control costs escalate cost
effectiveness will improve. The required rate of addition of AQ is fairly small (approximately 1 Ib/ton of pulp) and
does not require extensive process equipment modifications.69 Although pulp viscosity is reduced somewhat,
overall, pulp quality is similar to conventional cooking. Increased pulp yield of two to three percent has been
reported.78
Costs;
Addition of AQ catalysis to an existing mill requires minimal capital investment Increased operating costs,
however, are not completely offset by reductions in bleaching chemical usage.69
References:
69, 78, 158
•42-
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OZONE DELIGNIFICATION
Technology Descrintion:
Ozone delignification is the use of ozone (Oj) in alkaline conditions, to delignify pulp. This technology like
oxygen or peroxide delignification would occur before the chlorine stage of bleaching such that the waste liquor could
be removed from the process and disposed of in the recovery system.
Effectiveness:
The available literature does not discuss TOC1 analysis but one reference states that acidification of pulp followed by
ozone treatment decreases kappa number of softwood pulps by 43% and of hardwood pulps by 47%.3S This degree of
delignification is similar to that obtained by oxygen delignification.
Installations!
At this time, the process is not commercially available and there are no known full scale installations.
Implementation:
A 1986 article reported that ozone delignification was operating at a pilot plant scale only.38 The available literature
discussing ozone delignification and associated pulp qualities appears contradictory. Reports range from stating that
development of ozone bleaching has been hampered by the poor selectivity and resulting carbohydrate degradation and
low yield and viscosity, to stating that O3 and O2 delignification have developed the same yield, final brightness and
strength.38-64
Costs:
Based on limited information, this technology is more expensive than oxygen or peroxide delignification and does
not result in any better pulp qualities than oxygen delignification.38'42*64
References;
34, 38,42, 53, 54, 64, 73, 188
43-
-------
PEROXIDE DELIGNIFICATION
Technology Description:
Peroxide delignification is applying hydrogen peroxide in an alkaline medium prior to the chlorine stage of
bleaching. Application of this principle is also covered under a separate section titled Peroxide Extraction. The
discussion in this section is primarily directed toward the patented MINOX process. This process involves mild
delignification of the brown stock pulp with hydrogen peroxide, high efficiency washing of the treated stock and
recycling of the peroxide effluent to the brown stock washer unit Chemical application is after brown stock
washing.
Effectiveness:
Peroxide delignification studies carried out on different types of pulps showed that 22-29% delignification could be
achieved on kraft hardwood, 25-42% on kraft softwood and 35-42% on sodium bisulfite hardwood. *** Operating data
from the Cellulose des Ardennes mill show that even for a mild delignification process, where the kappa number of
the brownstock hardwood pulp is reduced from 17 to 14.4, that the color of the effluent was reduced by 45%.1S4
Previously reported studies showed that peroxide delignification efficiency could be increased 40-60% by
demethylation of the pulp.42
Installations:
The MINOX process has been used for many years on unbleached sulfite pulps and in late 1979 it was implemented
on kraft pulp at the Cellulose des Ardennes mill in Harnoncourt, Belgium.154
Implementation:
One article states that EQP can be used efficiently as a first bleaching stage in sulfite pulp mills but that due to the
high content of heavy metal ions in kraft pulp brownstock it cannot be used for kraft pulp bleaching without an
additional stage for eliminating heavy metal ions.79 Information related to the operation of the Cellulose des
\
Ardennes facility and research by PAPRICAN did not discuss any problems associated with heavy metal ions.149
Costs:
Capital cost data was not found in the literature, however, costs should be similar to those for oxygen delignification
as the basic equipment needed is similar. One major difference would be in the retention tower which for peroxide
delignification is approximately two hours as compared to oxygen delignification where the retention is 30 to 60
minutes. For retrofit situations, one author suggests that the P stage could be carried out in the high density storage
tower and post bleaching could be reduced to three or four stages to reduce capital cost154 Costs reported for the one
operating facility showed a savings of 1.1 S/ADT of pulp in direct operation costs.154
•44-
-------
42, 79, 149, 154
•45-
-------
VI. MINIMIZATION OF CONTAMINATION THROUGH PROCESS CHANGES
BLEACHING
AVAILABLE TECHNOLOGIES
CHLORINE DIOXIDE SUBSTITUTION
Technology Description!
Chlorine dioxide (C1O2) substitution is the replacement for some portion or, in some cases, all of the chlorine gas
(Clj) used in the first bleaching stage for delignification. Chlorine dioxide is a more powerful oxidizing agent than
chlorine, providing about 2.63 times the oxidizing.povyer_pf.an.equivalent amount of chlorine. The amount of
substitution or replacement is expressed as a percent of the total equivalent chlorine used and high substitution is
loosely defined as 25 percent or greater103
Chlorine dioxide must be produced and consumed on-site as it is unstable and not suitable for long-term
transportation or storage. There are six commercial C1O2 generators on the market today. 10° Each is operated with a
reducing agent (SOj, methanol, chloride ion from NaCl, or HC1), to form C1O2 and various by-products ranging
from chlorine, sodium sulfate and acid effluents. Selection of a particular generating unit is mill-specific and may be
influenced by a number of process-related factors, most concerning consumption of residuals from the process
Chlorine dioxide has been used for pulp bleaching since 1946. In the 1960's the CEHDED and CEDED sequences
became dominant for producing full bleach kraft pulp. In the 1970's attention was given to replacing pan of the
elemental chlorine in the first bleaching stage with equivalent chlorine dioxide to improve strength and color
stability and reduce effluent color78 The use of C102 has been steadily increasing as shown in Figure VI-1.
\Vbrldwide production of pulp bleached with high chlorine dioxide substitution is estimated to have reached 6.9
million tons/year by the end of 1988.103 The degree of chlorine dioxide substitution at U.S. kraft pulp and paper
mills as of mid-1988 is presented in Table VI-1.
During the past two years, the pulp industry has been increasing C1O2 substitution at a relatively rapid rate. Pryke
lists the following reasons for this increase:103
• Lower bleach plant chemical consumption
• Lower bleach plant costs
• Improve effluent quality (color, toxicity)
• Reduced formation of chlorinated organics (AOX.TOX, TOC1)
Reduced formation of 2378-TCDD and 2378-TCDF
Various substitution methods are used in the industry and described in the literature. The two most common
methods are sequential (DC or CD dependent on which is added first) and mixed (D+Q. Studies have shown that
-46-
-------
10
8
4>
c 6
I'
o
a. 0
3 1970
Q.
6.9 million metric tons
1988
1975
1980
1985
1990
FIGURE VM CHLORINE DIOXIDE IN THE CHLORINATION STAGE"3
TABLE VI-1
CHLORINE DIOXIDE SUBSTITUTION
AT U.S. KRAFT MILLS (MID 1988)1*3
Percent
Substitution
0%
<5
5-10
10-20
20-30
30-40
40-50
>50
TOTAL
Number of Kraft
Bleach Lines
59
16
41
33
9
1
3
165
improved delignification is obtained by sequential addition with chlorine dioxide added first (DC).103 The DC mode
also generates less chlorate.22-26 Emphasis here will be to discuss chlorine dioxide substitution in general.
•47-
-------
Effectiveness:
Numerous studies have shown the influence of chlorine dioxide substitution on the formation and discharge of
chlorinated organics.22-26'39 As shown in Figure VI-2, increasing the substitution of C1O2 up to 50% results in
an increase in total chlorinated phenolics both for conventional and oxygen delignified kraft pulps. Beyond 50%
substitution, however, the total amount of chlorinated phenolics decreases at a rapid rate. The effect of chlorine
dioxide substitution on the formation of individual chlorinated phenolics such as di-, tri, and tetra-chloroguaiacols
have been studied and are reported in the literature.19-103 Formation of 4,5-dichloroguaiacol was found to increase
with increasing C1O2 substitution to 50%, then decrease as C102 substitution was increased. Formation of 3,4,5
trichloroguaiacol and 4,5,6 trichloroguaiacol and tetrachlorocatechol was found to decrease with increasing C1O2
substitution.
The impact of C1O2 substitution on the formation of AOX is shown in Figure VI-3. As can be seen, AOX
decreases linearly with increasing chlorine dioxide substitution. This relationship is further displayed in Table VI-
2 which also shows that increasing C1O2 substitution has little impact on the BOD discharged. Studies have also
shown that increased C102 substitution results in decreased color in the effluent109
TABLE VI-2
AOX AND BODS FOR VARIOUS LEVELS OF
CHLORINE DIOXIDE SUBSTITUTION133
CHLORINE DIOXIDE SUBSTITUTION
10% 30% 40% 50%
AOX, kg/tonne
E STAGE 3.52 3.36 3.13 2.37
UNTREATED EFFLUENT 3.42 - - 2.31
PRIMARY EFFLUENT 2.6 - - 2
AFTER 2.5 DAYS SECONDARY TREATMENT 1.45 - - 1.22
TREATED EFFLUENT (6 DAYS DETENTION) 1.39 - - 1.15
FINAL EFFLUENT BODS, tons/day 2.2 1.8 1.7 2.1
-v
The impact of chlorine dioxide substitution on the formation of 2378-TCDD and 2378-TCDF has been the subject
of numerous studies in the past few years. 40>90'9U62 One study done at a mill which employs oxygen delignification
showed that increasing the percent substitution of C1O2 resulted in a decrease in the amount of 2378-TCDD and
2378-TCDF produced and discharged, see Table VI-3. Another source reported that by increasing the chlorine
dioxide substitution from five to 50% reduced the discharge of CDDs and CDFs by over 50%.162 Most of the
studies pertaining to the impact of chlorine dioxide substitution relate to the reduction of the chlorine multiple. This
subject is covered in more detail in a subsequent section of this report entitled Control of Chemical
48-
-------
50
40
30
20
3 10
JL
O.
"5
- s
O)
w
O
UJ
X
Q.
g 1
O
0.5
0.2
0.1
Tetra-€hloropheno6c$
O--
\ Oj-bleached
\ (18.6)
\
10 30 50 70 90
ClOj IN FIRST STAGE, %
FIGURE VI-2 THE EFFECT OF CHLORINE DIOXIDE SUBSTITUTION ON TOTAL AND
TETRACHLORINATED PHENOLIC COMPOUNDS1*
Installations:
The number of U.S. bleach lines using C1O2 and the percent substitution for mid 1988 are shown in Table VI- 1 .
Since that time the number of mills employing C1O2 and the percent substitution has increased. In the June 1987
issue of Pulp &. Paper, the editor reported that In Canada nearly 90% of all bleach lines use more than 10% C1C>2 in
the C-stage.16
Implementation;
Some of the more positive effects reported as a result of applying a large quantity of C1O2 substitution (50% or
greater) when compared to 0 to 15% C1O2 substitution include: (a) no significant difference to improved pulp
viscosity and strength;26-38-68 (b) decreased sodium hydroxide consumption;38-42-6* (c) higher yield.68 Other
-------
a.
3
Q.
o
>*
O)
X
3
10
a Softwood,
O2-bleached, lab
o Hardwood, lab
_L
20
30
40
TOTAL ELEMENTARY CI2, kg/ton
t • i i t i
100
75
50 25 0
IN FIRST STAGE. %
FIGURE VI-3 THE EFFECT OF CHLORINE DIOXIDE SUBSTITUTION ON THE
FORMATION OF AOX1*
TABLE VI-3
DIOXIN AND FURAN RESULTS FOR VARIOUS LEVELS OF
CHLORINE DIOXIDE SUBSTITUTION133
CHLORINE DIOXIDE SUBSTITUTION
C-FILTRATE 2378-TCDD, ppq
C-FILTRATE 2378-TCDF, ppq
E-FILTRATE 2378-TCDD, ppq
E-FTLTRATE 2378-TCDF, ppq
TOTAL UNTREATED EFF. 2378-TCDD, ppq
TOTAL UNTREATED EFF. 2378-TCDF, ppq
SECONDARY EFFLUENT 2378-TCDD, ppq
SECONDARY EFFLUENT 2378-TCDF, ppq
10%
ND
ND
170
490
ND
63
ND
45
30%
ND
ND
65
320
ND
52
NOTTESTED
NOTTESTED
40%
ND
ND
190
1,000
NOT TESTED
NOTTESTED
NOTTESTED
NOTTESTED
50%
ND
120
ND
470
ND
ND
ND
ND
advantages claimed from use of chlorine dioxide include higher final brightness and better brightness stability
, . . . ..... . . .,. Material belongs to:
(percent substitution not speeded m article)." Office ofToxic Substances Library
U.S. Environmental Protection Agency
401 M Street, S.W. TS-793
-n Washington, D.C. 20460
(202)382-3944
-------
Some of the negative effects of increased C1O2 substitution reported in the literature include: (a) oxygen bleached
pulp is delignified by C1O2 considerably more slowly than non-oxygen bleached pulp. C102 and oxygen both favor
reaction with lignin containing free phenolic groups. Oxygen delignification specifically attacks such lignin,
therefore reducing the amount of free phenolic groups to react with ClO^59 Thus a bleaching sequence incorporating
oxygen delignification followed by high C1O2 substitution, the time required for bleaching may be increased; (b)
increased use of C1O2 will result in more salt cake by-product from C1O2 generation. This additional salt cake may
exceed that which is required for kraft mill make-up;69 (c) in laboratory tests, carbon monoxide (CO) was observed
during C1O2 bleaching of hardwood and softwood pulps. The amount of CO generated depends on the lignin content
of the incoming pulp (greater lignin yields more CO) and the charge of the C1O2 (a higher charge yields more CO)
and (d) significant amounts of chlorates are formed during bleaching with C1O2. In Sweden discharge of high levels
of chlorates was found to have a negative effect on ecologically important macroalgea (e.g. Fucus vesiculosus).'22
Biological treatment has been found to reduce these chlorates by 80%.180
Increasing C1O2 substitution within the generating capacity of an existing on-site CIC^ generator should be a
relatively short term project, and probably has been accomplished at most U.S. mills. However, as shown in Table
IV-1, presented earlier, few mills in the U.S. practice C1O2 substitution at the high rates noted above as necessary
to affect minimum formation of chlorinated organics. Currently there are numerous projects underway for increasing
chlorine dioxide substitution at bleached kraft mills such that delivery times for C1O2 generating equipment have
increased. Implementation time for these new large-scale C1O2 generating systems is probably now more affected by
equipment delivery than by engineering design or construction. One source gave an implementation time from date
of order to operation as 14-18 months.190 Another factor may be the availability of sodium chlorate which according
to a bleaching survey reported in June 1988 was in short supply.4
Costs:
The capital cost for a 30 ton/day system was provided by one source as approximately $2.8 million for equipment
with an installed cost of approximately $5.7 million.190 Data from five mill trials reported by Pryke and shown in
Table VI-4 show that bleach plant chemical costs are reduced with substantial chlorine dioxide substitution.
TABLE VI-4
MILL TRIAL CHANGES IN BLEACHING CHEMICAL CONSUMPTION AND COSTS1"
Mill A MillB MillC Mill D Mill E
Increase in C1O2 substitution, % 14 to 45 17 to 35 10 to 30 10 to 30 4 to 26
Total eqiriv. C12, % on pulp -0.74 -0.60 -0.95 -0.76 -0.74
Total applied NaOH,% on pulp -1.00 -0.45 -0.45 -0.68 -0.38
Bleaching cost, CDN$/a.d.ton -1.94 -1.55 -2.36 -3.20 -1.40
Bleaching costs were calculated using CDN$0.265/kg of C12, CDN$0.265/kg of NaOH, and CDN$1.10/kg of ClOj
-51-
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Reference^:
4, 16, 18, 19, 20, 22, 26, 30, 33, 38,40, 42, 44, 46, 47, 54, 58, 59, 62, 68, 69, 71, 73, 78, 85, 90, 91, 93, 95,
100, 103, 105, 109, 118, 121, 133, 143, 144, 149, 150, 162, 163, 166, 170, 172, 173, 178, 183, 185, 186, 188,
190,199
-52-
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OXYGEN EXTRACTION
Technology Description:
In conventional bleaching, an acidic chlorination stage followed by an alkaline extraction stage constitute the first
two bleaching stages. Adding elemental oxygen to the first extraction stage (El) reduces the need for subsequent
chlorine bleaching chemicals. Oxygen extraction can also be used prior to chlorination especially if combined with
peroxides as described in the next section.43'79'149'174
Effectiveness:
When replacing the El-stage with an Hostage in the (DC)EDED or (DQED sequence, pollution load can be reduced
by 25 to 30%. M Whereas BOD and COD are both reduced through use of oxygen extraction, oxygen delignification
and CIO 2 substitution are pointed out as being superior to E0 in reducing pollution.22-69 TOC1 reduction resulting
from installation of an oxygen extraction (Eg) stage is not discussed in the literature, but other parameters discussed
indicate pollution reduction and possible reduction in TOO. Three out of four articles stated that EQ reduces C1O2
and/or hypochlorite (H) consumption in kraft pulping, but no comparison was made showing TOO reduction with
associated reduction in C102 and/or H use.38'42-61-*9 As a possible indicator, one article reports that with 70% C102
substitution in the C-stage, a chloroform concentration of 0 |ig/g of oven dry pulp was measured in the effluent
filtrate.18 In the same study, the H stage generated 5 to 15 times as much chloroform as the C, E and D stages
combined. The article also stated that chloroform production from the D stage has been shown to be minimal. With
this in mind, E0 followed by D stages would be expected to have minimal effect at reducing chloroform whereas E0
followed bya hypochlorite stage would reduce chloroform formation by reducing hypochlorite consumption. At one
facility, installation of oxygen extraction improved bleaching by reducing kappa number after the CE sequence from
5.3 to less than 4.0 and the mill reduced hypochlorite use by 20 Ib/ton.50
Installations:
X
By the end of 1984, over 55 E0-stages (use of oxygen in the first alkaline extraction stage of chemical pulp
bleaching) were in operation.41 As of June 1987, in Canada, 80% of all bleach lines use oxygen extraction.16
Implementation:
In 1983, an oxygen extraction unit was installed at a 450 tpd bleach plant (softwood and hardwood) having an
original CEHH sequence. Construction of the project was completed in three months.50
The only potential problems identified in the literature were: (a) oxygen channelizing in towers leading to non-
homogeneous bleaching; and (b) the possibility of hazardous concentrations of hydrocarbons and carbon monoxide in
dead zones within the bleaching tower or bleaching building.61
-53-
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Costa;
The only capital cost information found discussed the 1983 oxygen extraction unit installation. The cost for the
installation was under $500,000. The same project reported capital costs being repaid after the first year of operation
due to hypochlohte savings. Use of oxygen extraction was reported by one company as resulting in a hypo savings
of 8.3 pounds/ADT a caustic savings of 12 pounds/ADT and a steam savings of 200 pounds/ADT resulting in an
approximate annual savings of $400,000 and a payout before taxed of 1.3 years.200 Another article reported
"phenomenal" operational savings of $400,000 to 800,000 (Canadian) per annum per installation.42 Other articles
report reduced Q02 and hypochlorite usage without presenting associated cost savings or increases.38-42-61 Article 42
states that for softwood pulps, savings of 6 kg/ton of hypochlohte and 2 kg/ton of C1O2 can be achieved in a
CDE0HDED sequence and 4 kg/ton of C1O2 in CDE0DED sequence with four to eight kg/ton of O2 applied. Use of
oxygen extraction at the SCA Ostrand mill is reported to have saved 16 pounds of bleaching chemical as active
chlorine per ton of pulp.65
References:
15, 16, 18, 19, 22, 28, 31, 38, 41,42, 43, 48, 50, 57, 61, 65, 69, 70, 73, 79, 83, 93, 127, 133, 149, 171, 172,
173, 174, 187, 188, 200, 202
-54-
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PEROXIDE EXTRACTION
Technoloy Descrition:
This technology is similar to oxygen extraction (EQ) in that a small percentage of hydrogen peroxide (HjO2) is added
to the alkaline extraction stage (Ep). Like EQ, adding peroxide to the extraction stage also reduces the need for
subsequent chlorine bleaching chemicals. Peroxide can also be added to or "reinforce" an Eo-stage (Eop) to further
reduce chlorine bleaching chemical usage.79
Effectiveness;
EOP or Ep after chlorination can be used to reduce hypochlorite and C1O2 in subsequent bleaching stages.28'79 In a
laboratory study,22 (DC)Ep sequence (H^02 of 0.2% per ton of pulp) reduced pulp kappa by 0.5 to 1.0 more than for
the (DC)E sequence. The addition of 0.3 to 0.4% peroxide to the Eo-stage is reported to increase delignification from
10-15% for E0 alone to 30 to 35%. 4 This increase in delignification is directly proportional to a decrease in chlorine
consumption which can be reduced from 20-35% through use of peroxide in the extraction stages.194 No specific
TOC1 analyses were presented but bleach chemical use, primarily C1O2 and hypochlorite will be reduced with the use
of peroxide in the Eo-stage for kraft pulp. It has been reported that using 0.1% peroxide in the second extraction
stage results in up to a 0.2% savings in chlorine dioxide which if used for substitution of chlorine in die first stage
of bleaching could results in a 5 kg/tonne reduction in elemental chlorine.194 At a minimum as with oxygen
extraction (EQ), peroxide extraction (Ep) or peroxide reinforced extraction (Eop) can reduce chlorate formation by
reducing CIO2 use. One article reported that the combining action of HjOj with that of oxygen makes it possible to
better control the oxygen-alkali extraction stage.
For sulfite mills, reinforcing on Eo stage with oxygen hydrogen peroxide (EQP) and placing the Eop as the first
bleaching stage can reduce chlorine consumption. In one comparison of a CEHH and (EoP)CHH sequences, it was
found that the (EOP)CHH process used less than one half the chlorine to bleach pulp to paper grade quality while
bleaching costs of the two processes were approximately the same.79
Installations:
The June 1987 Pulp &. Paper reported that in North America, 25% of the bleach lines use peroxide and that use of
peroxide grew by 30% from 1983 to 1987.16
Implementation!
The only limitation discussed was that pH must be maintained around 10.5.71
Costs;
No costs were provided for kraft pulping. For sulfite mills, the operating costs for a CEHH and (EQP)CHH were
reported to be about the same.79 Capital costs were not discussed.
-55-
-------
Costs need further investigation. One reference states that H^02 is expensive for bleaching chemical pulps as
compared to C1O2 but that as energy costs increase, the cost differential between the two chemicals rapidly
decreases.7* Another reference states that the economics of adding Hjp2 along with oxygen in the first extraction
stage, depends on relative costs of various chemicals but that in most cases, operating costs would be noticeably
decreased22 Ep-stage is financially less attractive than Eg.28
References!
15, 16, 22, 28, 38, 53, 54, 64, 73, 78, 79, 149, 167, 174, 188, 194, 195, 204, 206
-56-
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MONOX-L PULP BLEACHING PROCESS
Technical Description;
Monox-L is hypochlorous acid (HC10) plus an additive developed and patented by Quantum Technologies.
Hypochlorous acid (L), the hydrated form of chlorine monoxide, has been known of since the 1930s as an excellent
bleach chemical, however, it has not been used as it is quite destructive of the pulp.124 Quantum's developed additive
maintains bleaching characteristics without pulp destruction.124 In many ways, Monox-L can be compared to
chlorine dioxide due to its bleaching condition and abilities. The process equipment metallurgy required for Monox-
L is reported to be the same as that needed for chlorine dioxide.124
Effectiveness;
While Monox-L is generally used in place of chlorine dioxide it can be used to replace hypochlorite or hydrogen
peroxide. This replacement is reported to produce", a superior pulp in terms of brightness, viscosity, and chloroform
reductions.25 Research results reported by Quantum Technologies indicate that although L bleached samples show
some concentrations of chloroform present in the bleach filtrate (22 ppm), the quantity formed is much lower than
for die corresponding H stage (5.4 ppm).25 The L sample produced a pulp of higher brightness than the H sample
and formed about 60% less chloroform. ** A chlorine dioxide (C102) bleached sample was also tested for chloroform
formation. Although C1O2 itself does not form chloroform, 1.7 ppm of chloroform was present in the D-stage
filtrate which was most probably due to carry over from the previous bleaching stages.25 By comparison,
chloroform in the L-stage filtrate was 22 ppm which was only slightly higher than that formed during the chlorine
dioxide bleaching.25
While Monox-L has may similarities to chlorine dioxide, it is claimed by Quantum to offer numerous advantages
over chlorine dioxide such as lower energy requirements, lower capital and operational cost, less hazardous, and less
space requirements.m135 In addition to using Monox-L as a substitute for chlorine dioxide, research by Quantum
shows that when Monox-L is substituted for chlorine that the amount of AOX and dioxin is reduced in pulps and
bleach plant filtrates.130-135 The data are shown in Table VI-5 and Table VI-6.
.TABLE VI-5
AOX LEVELS IN FILTRATES FOR BLEACHED SCANDINAVIAN SOFTWOOD1"-1"
FIRST STAGE BLEACH CHEMICAL(S) AOX, kg/ADT
F5% ACTIVE CHLORINE1 C-STAGE E-STAGE TOTAL
C(90%)D(10%) 2.0 1.6 3.6
C(50%)D(50%) 1.42 1.38 2.8
L(100%) 1.03 1.13 2.26
L(50%)D(50%) 0.65 0.83 1.48
D(100%) 0.32 0.35 0.67
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TABLE VI-6
C-STAGE SUBSTITUTION WITH MONOX-L135
(TOTAL ACTIVE CHLORINE - 7.4%)
2378-TCDD, ppt 2378-TCDF, ppt
BLEACH SEQUENCE PULP FILTRATE PULP FILTRATE
LE ND - ND
LEH ND ND
LEHED ND ND
CE ....
CEH 38 - 20
CEHED 16 - 8
While these data do show a reduction in AOX and dioxin, there is no information about the quality of the final
product It is also interesting to note that while Monox-L substitution for chlorine results in lower AOX levels that
substitution of chlorine dioxide results in an even greater reduction of AOX.
The substitution of Monox-L for chlorine dioxide in the Dl or D2 stages of bleaching would allow for that chlorine
dioxide displaced to be substituted for chlorine in the chlorine stage. This would offer a means for mills with limited
chlorine dioxide generation capacity to increase the amount of chlorine dioxide in the chlorine stage of bleaching.
Installations!
A commercial size 20 ton per day Monox-L generator has been operating at the Kymmene Corporation mill at
Kuusankoski, Finland since February 1989.12* - This was the first commercial installation of the Monox-L
technology and resulted from two successful plant trials conducted in early 1988 and late 1987.12* Plant trials have
been recently run at Federal Paper Board - Riegelwood, N.C., Georgia-Pacific Corporation - Brunswick, Georgia, and
Temple-Inland, Inc. - Evadale, Texas.121 Based on these trials, Georgia-Pacific and Temple-Inland have purchased a
25 and 20 ton per day Monox-L generator, respectively, with start ups anticipated in the first quarter of 1990.135
Implementation!
Quantum estimates the time required for design, installation and start-up to be approximately six months from the
receipt of the purchase order, four months under expedited conditions, and nine months with approval delays.135
Costs:
The installed capital cost for a 20 ton per day Monox-L generator with prepaid license and royalty was recently
quoted by Quantum to be approximately $2 million.135'198 This cost can be compared to a comparably sized chlorine
dioxide generator costing $6-12 million plus royalty.135 The 25 ton per day unit and peripheral equipment at
Kuusankoski is reported to have cost just under $2 million.124 Operation and maintenance costs were quoted by
Quantum at approximately $9 per ton for Monox-L as opposed to $170 per ton of chlorine dioxide.135 When
-58-
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comparing costs one should take into account the fact that Monox-L replaces chlorine dioxide at a ratio of
approximately 1.2 pounds of Monox-L for 1.0 pound of chlorine dioxide.135 Another reference states that the
substitution of Monox-L for chlorine- dioxide results in a savings of approximately S5/ton of pulp.191
References;
25,124,130,135,198
-59-
-------
CONTROL OF CHEMICAL DOSAGE
Technology Description!
The chlorine ratio is the amount of equivalent chlorine, including that contributed by chlorine dioxide, consumed in
the first pulp bleaching stage in relation to the lignin content of the incoming pulp, expressed as the kappa No. The
chlorine ratio, also referred to as the chlorine multiple or kappa factor, is computed as follows:
Chlorine ratio = [((Cl2+2.63*C102)/2000)*lOO]/kappa No.,
where C12 and C102 are chemical application rates in Ibs/ton of air-dried brownstock pulp.
Research conducted in Sweden has demonstrated that control of chlorination by monitoring the chlorine ratio can be
effective for minimizing formation of 2378-TCDD and 2378-TCDF. Laboratory and mill scale trials indicate that
formation of 2378-TCDD/TCDF is substantially reduced at chlorine ratios of 0.15 and less and increased at chlorine
ratios of 020 and above. As of mid-1988, chlorine ratios for most U.S. bleach lines were found to be above
0.20.163 Researchers report that overchlorination, even for brief periods of time can result in excess formation of
2378-TCDD/TCDF. Accordingly, chlorine minimization to achieve low chlorine ratios and close monitoring of
chlorine application are necessary to affect control via chlorine ratio. For many U.S. bleach lines, the types of
instrumentation and controls for chemical application rates are not advanced. Monitoring and control of chemical
application rates to the degree necessary to control the process by chlorine ratio may not be possible without
improved controls or close operator attention. Nonetheless, the research suggests that minimizing chlorine
consumption and overchlorination will have beneficial impacts on reducing formation of 2378-TCDD/TCDE
Effectiveness:
Laboratory experiments, confirmed by mill scale trials, demonstrate that control of the first bleaching stage by
chlorine ratio was effective at substantially reducing formation of 2378-TCDD/TCDF. These results are shown in
Figure VI-4 and suggest that chlorine ratios below 0.15 are essential for minimizing formation of 2378-TCDD
and 2378-TCDF.
Installations:
At this time it is not known how many mills are operating bleach plants to control the chlorine multiple at a level
of 0. IS or less as a means to reduce the amount of dioxins and furans produced. Recent submissions by many of the
104 mills studied by EPA and the Paper industry indicate that efforts are being made by many mills to reduce their
chlorine multiple toward the 0.15 level163
-60-
-------
12
a
a
I •
ai
o
z
O
o
-Lab Min
o • Softwood
A A Softwood,
O^bteached
1
0.05
0.10
0.15 0.20
(US
0.30
CHLORINE MULTIPLE
FIGURE VI-4 THE EFFECT OF CHLORINE MULTIPLE ON 2378-TCDD IN PULP1*
Implementation:
Implementation time for minimizing chlorine consumption and overchlorination in the first bleaching stage within
the capability of existing instrumentation and monitoring equipment at a mill should be a relatively short term
project, perhaps taking a few months. Retrofitting more sophisticated controls on existing bleach lines to more
closely continuously control chemical application rates may take several months or longer, depending upon
availability and delivery of equipment Additional research is necessary to determine the current state of the market
Costs:
Costs for minimizing chemical applications at existing bleach lines should be minimal, exclusive of new
instrumentation and controls. Costs for new systems are highly site-specific. Generalized costs are not available at
this writing.
References:
13, 17, 19, 23, 26. 30, 33, 40, 85, 90, 91, 93, 103, 105, 118, 141,149,183
-61-
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IMPROVED MIXING
Technology Description:
Effective chlorination stage mixing is important to reduce bleaching costs through more effective use of chemicals,
to reduce downstream equipment requirements for new bleach plants, and to minimize formation of chlorinated
organic compounds in bleached pulps and bleach plant process wastewaters. Prior to the early 1980's, most in-line
mixers in use for chlorine addition were of the static design. Recently, high intensity mixers have become more
popular for the reasons set out above. With the strong trend toward increased chlorine dioxide substitution for
chlorine, additional mixers are necessary as C1O2 is usually applied upstream of chlorine addition for maximum
benefit Thus, at many mills, reconfiguration of the mixing systems and chlorination stages has occurred or is
underway to accommodate increased C1O2 substitution. In most cases, combinations of various types of mixers are
used to attain desired results.
Effectiveness:
Although little published data are available that specifically address the effectiveness of improved mixing on
formation of chlorinated organics, several researchers have cited high efficiency chemical mixing and sequential or
multi-step chlorine additions as important variables in that regard.52 High efficiency mixing has also been cited as
an important factor to minimize localized overchlorination and thus formation of 2378-TCDD/TCDF.
Implementation;
No information on implementation time is available at this writing, although, depending upon the system design
and extent of bleach plant modifications, implementation times of several months to more than one year would
appear reasonable.
Costs:
A new high shear mixer recently installed at one location was reported to have cost $160,000.134
References;
41, 42, 46, 47, 50, 52, 90, 104, 115
-62-
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SPLIT CHLORINE ADDITION AND pH ADJUSTMENT
Technology Description;
The technology consists of process modifications which allow for chlorine/chlorine dioxide to be added in several
small sequential charges rather than in a single charge and modifications which allow the pH of the chlorine stage be
controlled to higher levels than conventionally practiced. Research at Westvaco showed that the rates of formation of
2378-TCDD and 2378-TCDF are more dependent on the concentration of the chlorine than on the absolute amount
of chlorine used, or on the ratio of chlorine to the kappa numbet52 By applying the chlorine in several charges
throughout the reaction time, the chlorine concentration "profile" can be kept lower.52 Chlorine reacts with the
residual lignin in the pulp by oxidation and by substitution mechanisms. While oxidation leads to more soluble
lignin products, substitution results in the creation of chlorinated organics including CDDs and CDFs. Numerous
studies have been carried out in an attempt to distinguish between these two reactions or to determine how to
manipulate bleaching conditions to favor oxidation. In addition to lowering the concentration of chlorine through
smaller additions, the concentration can also be reduced by upward adjustment of the pH. This fact is well
documented in the literature, however, is not usually practiced because such adjustment results in a degradation of
cellulose as seen by a decrease in pulp viscosity. Westvaco has developed operating conditions that control this loss
of viscosity.52
Effectiveness!
Laboratory studies performed by Westvaco showed that by splitting the chlorine charge into three smaller doses,
2378-TCDF and 2378-TCDD concentrations in the pulp were reduced by about 70% and 50%, respectively.52 In
conjunction with the split chlorine charge, it was also found that by increasing the C-stage pH both 2378-TCDD and
2378-TCDF levels in the pulp were reduced by more than 90%.52 Initial full scale mill trials have confirmed the
capability to manufacture high-quality bleached products with nondetectable levels of 2378-TCDD and less than six
parts per trillion of 2378-TCDF in the pulp.52 The system has also been shown to be effective on both hardwood
and softwood bleach lines with softwood showing the greatest response.52
The process changes modification were initiated at the Westvaco Luke mill in May 1989. CDD/CDF sampling and
analysis performed both before and after these changes were initiated are presented in Table VI-7. During the
period May 1989 through September 1989, only two of three planned addition points were in operation and during
some months trial runs employing chlorine dioxide substitution and peroxide reinforcement were being performed.
As can be seen from this table, the 2378-TCDD/TCDF levels have been reduced significantly in the pulp as well as
in the effluent and sludge as a result of the changes made to date. The company is hopeful that when all the changes
are completed and the additional chlorine dioxide substitution is on line that the levels of 2378-TCDD/TCDF will be
even lower.134
•63-
-------
TABLE V-7
WESTVACO (LUKE, MD) DIOXIN/FURAN ANALYSES
BLEACH PLANT PULP
CHLORINATION STAGE FINAL BLEACH STAGE
DATE SPECIES
9/87
6/88
12/88
1/89
2/89
3/89
4/89
5/89
5/89°
6/89
7/89
8/89
9/89
Blend
Blend
Blend
Blend
Blend
Blend
Blend
Blend
Blend
Blend
Blend
Blend
Blend
8-TCDD
(ypt)
43
-
4.0
ND(4.4)
-
.
.
-
-
-
-
-
ND(0.05)
2378-TCDF
(ppO
124
-
18
ND(41b)
-
.
.
-
-.
-
-
-
0.39
2378-TCDD
(ppt)
36
29
2.6
ND(1.0)
4.4
2.8
ND(0.2)
ND(0.2)
ND(0.2)
ND(2.3)
ND(0.1)
ND(0.09)
ND(0.06)
2378-TCDF
(ppt)
143
157
20
4.5
10.2
ND(8.0b)
ND(1.4b)
0.56
0.56
ND(1.6)
0.77
0.8
0.95
SAMPLE
TYPE*
24C/W
120C/R
MC/W
MC/W
MC/W
MC/W
MC/W
MC/W
MC/W
MC/W
MC/W
MC/W
MC/W
WASTEWATER TREATMENT PLANT
INFLUENT EFFLUENT SLUDGE
2378 2378 2378 2378 2378 2378
DAT£
9/87
6/88
12/88
1/89
2/89
3/89
4/89
5/89
5/89"
6/89
7/89
8/89
9/89
TCDD
(ppgj
40
-
NDOO15)
-
-
-
ND(8)
-
-
-
-
ND(3) '
TCDF
(£Bfl)
350
-
151
-
.
-
40
-
-
-
-
10
TCDD
(Bpal
ND(14)
16
ND(8)
ND(13)
9.0
ND(10)
ND(5)
ND(8)
-
ND(3)
ND(1)
ND(I)
NIXD
TCDF
(ppq)
101
49
58
ND(26b)
17
18
20
ND(5)
-
ND(3)
5
4
ND(4b)
TCDD
(ypt)
47
80
13
ND(10.3)
7.2
3.5
4.6
ND(0.24)
ND(0.44)
ND(1.4)
3.2
0.6
1.1
TCDF
taai
524
471
56
37
24
7.6
17.4
1.7
1.9
1.9
38.0
4.6
13.9
SAMPLE
TYPE*
24C/W
120C/R
MC/W
MC/W
MC/W
MC/W
MC/W
MC/W
MC/W
MC/W
MC/W
MC/W
MC/W
24C/W • 24 hour composite/Westvaco
120C/R - 120 hour composite/Requested by Environmental Agency (104 Mill Study)
MC/W - Monthly composite/Westvaco
Estimated maximum potential concentration
Duplicate
-64-
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Installations:
As of the present date, this technology developed by Westvaco, has been installed at all three of its bleached kraft
mills. This includes two bleach lines at each of the Covington, Virginia and Luke Maryland mills and one bleach
line at the Wickliffe, Kentucky mill134 No other installations are known of at this time.
Implementation!
Westvaco's goal in undertaking the research was to develop an operation for significantly reducing dioxin levels that
could be implemented in a short period of time, would not require extensive capital and would not result in
production downtime. The system consists of valves, piping, pumps and high shear mixers all of which are readily
available and can be designed and installed in a short period of time. The total time that it took Westvaco, from the
date of decision until operation, for its Luke and Covington mills on an expedited schedule was seven to eight
months, whereas for the Wickliffe mill running on a more typical schedule, it was approximately 13 months.134
Costs;
Westvaco's dioxin control program for its three bleached kraft mills (Luke, MD; Wickliffe, KY; Covington, VA)
which includes five bleach lines was reported to have a capital cost of 25 million dollars.134 In addition to the split
chlorine addition and pH control process changes, this total cost also includes additional C1O2 generation equipment
at all three mills.134 Of the total 25 million total, ten million was spent at the Luke mill where the changes were
added to two bleach lines and 16 tons/day of C1O2 generation was added134
References:
81, 82, 134
-65-
-------
MONITORING OF KAPPA NUMBER
Technology Description!
On-line measurement of kappa number is now possible with an optical analyzer developed and patented by STFI
(Swedish Pulp and Paper Research Institute) and called the STFI OPTI-Kappa analyzer*. The STFI method is based
on the ultraviolet light adsorption by the lignin in the pulp. Results are obtained in approximately five minutes as
compared to the laboratory method which takes about one hour. Correlation with the laboratory methods are reported
as very good for all species and a wide kappa number range.122 The ability to measure kappa number on-line means
that mills through close control of bleach chemical dosages can control the chlorine multiple as a method of reducing
the amount of dioxins and furans produced as discussed previously in this document.
Effectiveness:
Use of this technology not only allows for the control of the chlorine multiple but can result in a reduction in the
variation in the kappa number and a general reduction in the kappa number with no loss of product quality. One
reference reports that at one installation the variability in the kappa number was reduced by 50% and the target kappa
number was decreased by one to two kappa number units without any change in pulp quality.122 Both of these
results in the ability to reduce the chemical bleach dosage with results in the decrease in production of chlorinated
organics. Results from the Iggesund mill showed a decrease in residual chlorine by about 3 kg Clj/ton of pulp,
which corresponds to a decrease in the charge of active chlorine by 6-8 kg/ton.m This is reported to not only result
in reduced production cost but reduced environmental effects.111
Installations:
Installations of the STFI OPTI-Kappa Analyzer are provided in Table VI-8.
Implementation!
Delivery time for the STFI OPTI-Kappa Analyzer was provided by the supplier as running from 10 to IS weeks.151
Costs:
The capital cost of the unit including sensor, one sampling point, and computer installed and calibrated is
approximately $196,000.1S1 Each unit will handle up to three sampling point with each additional sampling point
costing approximately $20,000.m ABB Industrial Systems Inc. who market the STFI OPTI-Kappa analyzer in
North America, claim that the capital cost of the analyzer can be paid back is less man one year from the chemicals
saved in the bleach plant These annual chemical savings were reported by one author as SEK 1.5 million.122
Another reference stated that bleach costs were decreased $2.4 per ton of pulp.111
References!
111,122,151
-66-
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TABLE VI-8
WORLDWIDE STFI OPTI-KAPPA* INSTALLATIONS REFERENCE LIST*
CUSTOMER
Sodra Skogsagarna AB
STFI
NCBAB
MoDoCellAB
AB Iggesunds Bruk
ASSI Frovifors Bruk AB
SCA Pulp AB
Holmen Cell Kraft
Holmen Cell Kraft
NorrsundetBrukAB
STORA Cell
STORA Cell
MoDoCellAB
Soda Skogsagarna AB
KorsnasAB
Champion International
STORA Cell
ModoCellAB
ASSI Kraftliner
Willamette Industries
Oji Paper
Willamette Industries
Jujo Seishi
KymmeneAB
BahiaSul
Akita
Champion International
Nekoosa Papers, Inc.
LOCATION
Monsteras, Sweden
Stockholm, Sweden
Vallvik, Sweden
x
Husum, Sweden
Iggesund, Sweden
Frovi, Sweden
Ostrand, Sweden
Skarblacka, Sweden
Skarblacka, Sweden
Norrsundet, Sweden
Skutskar, Sweden
Skutskar, Sweden
Husum, Sweden
Morrum, Sweden
Gavle, Sweden
Pensacola,FL
Graven, Sweden
Domsjo, Sweden
Lovholmen, Sweden
Bennettsville, SC
Japan
Hawsville, KY
Yatsushiro, Japan
Jakobstad, Finland
Brazil
Japan
Pensacola, FL
Nekoosa, WI
APPLICATION START-UP
Oxygen Delig., C/D 1984
Bleach Swing Digester
Testing 1984
Oxygen Delig., C/D El Bleach 1984
Digester Feedback
Oxygen Delig., C/D El Bleach 1985
Digester Feedback
C/D, El Bleach Digester 1986
Feedback, Carryover Comp.
Fiber Identification Stock Prep. 1986
Refiner Control
Oxygen Delignification 1986
Digester Feedback
(6) High Yield Batch 1986
Digester, Stock Prep.,
Refiner Control
Oxygen Delignification 1986
Digester Feedback
Oxygen Delig., Kamyr 1987
C/D,. El Bleach
(3) Kamyr Control 1987
Oxygen Delignification
Oxygen Delignification 1987
C/D, El Bleaching
(2) C/D, El Bleach 1987
(8) Batch Digester
Oxygen Delignification 1987
Batch Digester
Oxygen Delignification 1988
Digester Feedback
Oxygen Delignification 1988
Digester Feedback
Oxygen Delignification 1988
Digester Feedback
Sulfite Digester 1988
C/D, El Control
High Yield Digester 1989
RDH Digester 1989
Oxygen Delig., C/D, El
Oxygen Delignification 1989
C/D, El Bleach 1989
(5) Batch (Hardwood)
Oxygen Delignification 1989
Blow line sampling 1989
Oxygen Delignification 1990
1990
Blowline sampling 1990
Bleach Plant Control 1990
-67-
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TABLE VI- (CONT)
WORLDWIDE STFI OPTI-KAPPA* INSTALLATIONS REFERENCE LIST*
CUSTOMER LOCATION APPLICATION START-UP
Willamette Industries Hawsville, KY #2 Bleach Line 1990
Source: Asae Brown Boveri (ABB) Industrial Systems, Inc.
-68-
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EMERGING TECHNOLOGIES
SLC®EXTRACTION PROCESS
Technoloev Descriotion:
Suppressed lignin condensation (SLQ is a proprietary process designed to reduce the amount of dissolved lignin that
precipitates back onto fibers following the C-stage of bleaching. This is accomplished by separating the liquid phase
of the alkali treated chlorinated pulp after one to two minutes of reaction, treating that liquid and then returning the
liquid to the pulp. This process results in a reduction of the CEK number thereby reducing the amount of chemicals
needed in subsequent bleaching stages.24
Effectiveness!
Pilot plant studies have been performed at two facilities, one a softwood kraft and the other a hardwood kraft mill.24
Results of these studies showed a reduction in CEK of 26 and 24% for softwood and hardwood, respectively.24 Also
shown was a reduction in chlorine consumption by ten% while maintaining the same reduced CEK number.24 This
reduction in CEK number resulted in a 472% reduction in the amount of hypochlorite needed in subsequent bleach
stages for hardwood pulp.24 No figures were provided for softwood pulp.
Installations:
No full scale application have been reported.
Implementation:
SLC is an add-on process, requiring minimal alteration of existing process units. Additional equipment needed for
the SLC process include a low consistency mixer, holding tank, thickener, filtrate tank and a small filtrate reactor
with heating provisions.24 Process availability is uncertain, due to its proprietary nature.
Costs;
Capital and operating and maintenance costs are unknown. Chemical savings based on reduced bleaching
requirements have been estimated at $4.41 per air-dry ton.24 In addition, reduced steam usage has been predicted that
would result in additional cost savings of $1.35 per air-dry ton.24
References:
24
-69-
-------
RAPSON-REEVE CLOSED CYCLE
Technology Description;
The Rapson-Reeve process is based on eliminating discharges from the bleach plant by recycling the bleach plant
filtrates to the pulp mill. The organics in these filtrates are incinerated in the recovery boiler, the sodium chloride
introduced in the process from the use of chlorine based bleach chemicals is removed through the Salt Recovery
Process (SRP) and the salt cake produced is used as make up chemical for chlorine dioxide production. The concept
of this process and its details have been published in numerous articles, three of which are included in the reference
list attached to this paper.148-155-161
Effectiveness!
The process was conceived to completely eliminate the discharge from the bleach plant In actuality the facility ran
in the range of 50-70% recycle of the filtrate streams due to problems encountered.161
Installations!
This technology was applied full scale at the Great Lakes Forest Products Limited (now Canadian Pacific Forest
Products Limited) bleached kraft mill, ('B' mill) in Thunder Bay, Ontario, Canada. The mill was started up in
November 1976 and the recovery of bleach plant effluent began in March 1977 with completion of the SRP. In
1988, mill management decided to abandon the process and build an external wastewater treatment system in order to
meet the Province's waste discharge limitations. At the present time there are no installation of the Rapson-Reeve
Closed Cycle technology in operation, although interest in the process remains high. With the great reductions in
chlorine usage made through extended delignification, oxygen delignification, oxygen extraction and high chlorine
dioxide substitution and the resolution of the problems encountered as discussed below.this process may prove to be
technically and economically feasible.
Implementation:
As expected with any new process of this magnitude there were a number of operating problems encountered with
start-up. Many of these were resolved through minor process modification, however even after these modifications
were made, the facility was not able to achieve total recycle of the bleach plant filtrates. Some of the problems
encountered are as follows
(1) Corrosion - Even though considerable effort was spent in the selection of metallurgy for the
closed-cycle system, corrosion problems were encountered. Within two years corrosion of the
recovery furnace superheater caused tube failure and the tubes had to be replaced. As a result of this
the system operated at a lower recycle rate to reduce the chloride buildup
-70-
-------
(2) Pitch buildup - When the mill switched to alternating between softwood and hardwood pitch
buildup became a problem when aspen was pulped and the quality of the product could not be
maintained.
(3) Chemical recovery - The high chloride content of the liquor caused a reduction in the temperature
of the smelt causing a problem with bed maintenance.
(4) Causticizing area • During closed cycle operation problems were encountered with lime reactivity
and lime settling.
CostSI
The capital cost of the entire bleach plant is reported to have cost $8 million in 1977. The operation cost for this
system based on 1979 data (assuming 0.80 US dollar/Canadian dollar) was estimated to be $5.99/air dried ton of
pulp.148 This cost includes the costs of steam production and consumption, bleach chemical consumption, salt
production, defoamer use, treated water consumption, operating cost of salt recovery process plant and the increased
cost of high CIO2 substitution.148 Not included in these costs were costs of installation or costs associated with the
higher equipment replacement cost as compared to a conventional mill due to the reduced life of equipment caused by
increased corrosion.148
References!
148, 155,161
-71-
-------
VH. WASTEWATER TREATMENT TECHNOLOGY
PHYSICAL/CHEMICAL TREATMENT
ULTRAFILTRATION
Technology Description;
As seen in Table II-2 and discussed previously, approximately 75% of the chlorinated organics by weight in the
spent extraction liquor have a molar mass greater than 10,000 g/mole. For the separation of molecules of this size,
membrane technology can be used. The membrane process ultrafiltration utilizes a semipermeable membrane for
separation purposes. These membranes can be specified by the size of the molecules they retain. Four different
configurations are available: tubular, hollow fiber, flat sheet, and spiral wound. By using a pressure drop across the
membrane, a permeate of water and low molar mass compounds go through the membrane, while a concentrate of
the high molar mass compounds are retained on the feed side. The concentrate can be disposed of by incineration in
the recovery furnace as is practiced by two Japanese mills employing the technology.32
Effectiveness:
A number of investigators have reported on the use of ultrafiltration for the treatment of pulp and paper mill waste
streams. Test results from a Canadian kraft mill provided below in Table VII-1 showed that 65% of the
organically bound chlorine was separated into a concentrate stream that was 6% of the feed flow.32 Based on actual
mill-site tests, color removals of 86% were obtained.32
TABLE VIM
ULTRAFILTRATION TRIAL RESULTS32
Filtrate, Concentrate,
Effluent Feed % of Feed % of Feed
Flow: 10.3 m3/adt 94 6
BOD: 13.5kg/adt 55 45
COD: 63,0kg/adt 34 66
Colour 332.8 kg/adt 13 87
Total Solids: 1163 kg/adt 67 33
Organics: 39.9 kg/adt 34 66
C1-: 31.7 kg/adt 97 3
Organic Chloride: 42 kg/adt 35 65
Na+: 30.7 kg/adt 88 12
Resin & Fatty Acids: 104.6 g/adt 30 70
Total Chlorinated Phenols: 36.0 g/adt 100 0
-72-
-------
Tests by Lundahl at the Iggesund, Sweden mill show similar results.147 These data compare very well to actual
performance data for three mills provided in Table VII-2. These studies also show that the ultrafiltration
membranes do not reject chloride ions. Lundahl also showed that ultrafiltration caused no significant reduction in the
toxicity of the E-stage effluent1*7
TABLE VII-2
EFFLUENT REDUCTION DATA FOR COMMERCIAL
ULTRAFILTRATION PLANTS"-1"-1"
Sanyo Pulp Mill Taio Paper Co. MoDoCell
COD Reduction, (%) 82 79 65
Color Reduction, (%) 94
AOX Reduction, (%) - - 70
Chlorophenols Reduction, (%) - - 10-20
Installations!
Three installations are referenced in the literature. These include two in Japan, Sanyo Kokusaku Pulp Mill and Taio
Paper Company, and one in Sweden, MoDoCell at Husum.88-116 The Sanyo mill treats only the E-stage effluent
from its hardwood line which constitutes about one third of its total production.141 The Taio Paper Co facility is a
large complex including facilities for producing bleached kraft pulp, semi-bleached pulp, unbleached kraft pulp,
TMP, groundwood pulp and deinked waste paper. At this facility the E-stage effluent from the bleached kraft mill is
treated.14* The Husum mill also treats the E-stage effluent from its facility.
Implementation!
Technical problems associated with the ultrafiltration process as applied to bleach plant effluents have been identified
by Jain and include the following:14S
(1) Low initial flux rates and gradual decline in flux rates with time of operation.
(2) Effect of burning ultrafiltration concentrate on chloride buildup in the chemical system, and its
impact on the recovery process, particularly at those facilities that do not have high SO2 emissions,
and, consequently, cannot purge chlorides as HC1 from recovery furnaces.
(3) Absence of technologies for final disposal of the ultrafiltration concentrate if burning in the recovery
furnace is not feasible.
(4) Inadequate information on the nature of membrane deposits, and procedures for cleaning membranes
to restore their initial flux rates.
No information could be found as to the time required for design and construction of these facilities.
-73-
-------
Costs;
Jonsson reports that the E-stage effluent from a kraft pulp mill can be treated by ultrafiltration for less than one% of
the sales value of bleached kraft pulp." The estimated total annual cost of 25 SEK per metric ton of pulp was
reported by Jonsson.M This cost includes an amortized capital cost of 12 SEK per metric ton based on an interest
rate of 15% and a pay back period of ten years and an operating cost of 24 SEK per metric ton, and credits of 11 SEK
per metric ton.88 The operating costs include electricity, cleaning, membrane replacement and evaporation of
condensate and the credits include the heat value of the condensate and the recovery of sodium. In these cost
estimates actual costs from the two Japanese facilities for electricity, cleaning and membrane replacement were
utilized.8' Dorica, et al, estimated the fixed capital investment (equipment cost x 2) for complete effluent recycling
of bleach plant effluents using combinations of ultrafiltration and reverse osmosis at S20.5 million (CDN) and $42.5
million (CDN) for a 625 od ton/day and 890 od ton/day, respectively.32 Of these costs, $1.17 million (CDN) and
$3.51 million (CDN) were for the ultrafiltration of the extraction wastestream.32
References:
32, 35, 85, 88, 116, 117, 127, 147, 148, 164, 178
-74-
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CHEMICALLY ASSISTED CLARIFICATION
Technology Description;
Dissolved and colloidal panicles in wastewater streams are not readily removed from solution by simple settling.
Chemically assisted clarification (CAC) consists of adding various chemicals to wastewaters for the purpose of
precipitation, flocculation, coagulation or agglomeration in order to change the state of the pollutant or to cause it to
be removed through physical means such as sedimentation or flotation. Chemicals in common use include lime,
alum, ferric chloride, ferric sulfate, magnesia and a myriad of polyelectrolytes. A number of CAC processes have
been patented including the lignin removal process (LRP) and the Hansel process.
The LRP process consists of adding acidified sludge to the waste stream to be treated, a retention period of 2-4
minutes, adjustment of the pH to 4.6-5.3 with lime or caustic, polymer addition (1-4 mg/1), and sedimentation for 2-
4 hours.84 The majority of the settled sludge (80-90%) is recirculaied back to the beginning of the process.84
The Hansel process involves the use of certain polymers used in the past but at lower dosages due to a technical
advance which has been patented. It is claimed that the additive concentration in the Hansel process are at least an
order of magnitude lower, that the sludge created is denser and that the character of the sludge makes it easier to
dewater than traditional alum-based sludges.125
For the most pan use of CAC in the pulp and paper industry in the past has been for the purpose of reducing the
color in the wastewater. The source of the color is large molecular organic compounds derived from the natural
lignin and tannins in the wood.
Effectiveness:
Bench scale studies were performed by EPA to determine if CAC was a viable treatment technology for the removal
of 2378-TCDD and 2378-TCDF. These investigations demonstrated that more than 95% of the 2378-TCDD and
2378-TCDF in the caustic extraction stage and in the combined bleach plant wastewaters were removed through use
of CAC.2 These removals were achieved at substantial dosages of alum (2000 mg/1) or lime (1500 mg/1) plus the
addition of polyelectrolytes.2 In addition, studies performed on the aeration basin mixed liquor showed that a limited
improvement in the removal efficiency for 2378-TCDD and 2378-TCDF were achieved through the use of
polymers.2 Studies on the final effluent showed marginal improvement in effluent quality for TSS and 2378-
TCDF.2 Results of these studies are provided in Table VII-3.
NCASI also performed a screening study of the treatability of dioxins and furans in bleach plant filtrates and mill
wastewaters. Results of these investigations were similar to those reported by EPA. Removals in excess of 98%
were observed in bleach plant filtrates at coagulant dosages of 9000 mg/1 lime or 9000 mg/1 alum.27 Studies
performed on the final effluent resulted in nondetectable levels of 2378-TCDD and 2378-TCDF with removal rates in
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TABLE VII-3
USEPA BENCH SCALE WASTEWATER TREATABILITY STUDY RESULTS - MILL
UNTREATED
Caustic Extraction ^
TSS 40
TOC 290
2378-TCDD 0.50
2378-TCDF 2.15
Combined Bleach Plant
TSS 86
TOC 190
2378-TCDD 0.20
2378-TCDF 0.88
Aeration Basin Effluent
TSS 3700
TOC 400
2378-TCDD 0.84-0.85
2378-TCDF 2.63
Aeration Basin Effluent
TSS 3700
TOC 400
2378-TCDD 0.84-0.85
2378-TCDF 2.63
Final Effluent
TSS 23
TOC, 48
2378-TCDD 0.009-0.012
2378-TCDF 0.043
TREATED % REMOVAL
18
150
<0.019
<0.039
19
120
<0.010
70
57
<0.030
0.091
17
48
<0.016
<0.016
15
22
<0.043
<0.02
55
48
>96
>98
78
37
>95
>98
98
86
>96
>96
>99
88
>98
>99
35
54
>53
TREATMENT
Alum (2000 mg/1)
Nalco 7769 (7.5 mg/1)
(anionic)
Lime (1500 mg/1)
CalgonWT2439
(5.0 mg/1)
(cationic)
Gravity Settling
No Additives
American Cyanamid
1906 N (625 mg/1)
(non-ionic)
Alum (200 mg/1)
Calgon 2136 (4.0 mg/1)
(cationic)
NOTE: 1. Use of products or mention of trade names does not constitute endorsement
2. Analyses for TSS and TOC by E.C. Jordan Co.
3. Analytical results for total suspended solids (TSS) and total organic carbon (TOC) are reported in mg/1
(or ppm); analytical results for 2378-TCDD and 2378-TCDF are reported in pg/gm (or ppt).
excess of 88% at coagulant dosages of 2500 mg/1 lime or 2500 mg/1 alum.27 Results of these investigations are
provided in Table Vn-4.
Studies were also performed by NCASI on the same wastewaters using only polymer. These studies showed that 93-
94% removal of 2378-TCDD and 2378-TCDF could be achieved in the secondary treatment influent at dosages of 2-
20 mg/1 and that at polymer dosages ranging from 4-12 mg/1 2378-TCDD removals of 18-27% and 2378-TCDF
removals of 35-54% could be achieved in the secondary effluent27
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TABLE VII-4
NCASI RESULTS OF 2378-TCDD AND 2378-TCDF ANALYSES FOR
TREATMENT OF KRAFT MILL "A" EFFLUENTS27
Bleach Plant Filtrate
2378-TCDD
2378-TCDF
Bleach Plant Filtrate
2378-TCDD
2378-TCDF
Bleach Plant Filtrate
2378-TCDD
2378-TCDF
Bleach Plant Filtrate
2378-TCDD
2378-TCDF
Final Effluent
2378-TCDD
2378-TCDF
Final Effluent
2378-TCDD
2378-TCDF
Final Effluent
2378-TCDD
2378-TCDF
Final Effluent
2378-TCDD
2378-TCDF
UNTREATED
1.5
37
1.5
37
1.5
37
1.5
37
0.093
2.6
0.093
2.6
0.093
2.6
0.093
2.6
TREATED
1.2
37
ND(0.027)
0.23
1.2
31
0.021
0.23
0.050
1.4
ND(0.011)
ND(0.006)
0.048
0.98
ND(0.006)
ND(0.008)
% REMOVAL TREATMENT
Lime (500 mg/1)
20
0
>98
99
20
16
99
99
46
46
>88
>99
48
62
>94
>99
Lime (9000 mg/1)
Alum (500 mg/1)
Alum (9000 mg/1)
Lime (200 mg/1)
Lime (2500 mg/1)
Alum (200 mg/1)
Alum (2500 mg/1)
Pilot plant studies performed utilizing the LRP process showed that up to 70% removal of TOO, 95% of color and
59% of chlorinated phenol could be achieved treating the total mill waste for a softwood kraft mill.84 Similar studies
on hardwood kraft resulted in lower removal rates. Results of these studies are presented in Table VII-5.
Studies done at the Champion Canton mill utilizing the Hansel process are reported to have resulted in the reduction
of color from an influent ranging from 1,000-1,200 Pt-Co color units (PCU) to 80 PCU, resulting in the production
of 1.36 pounds of sludge per 1000 gallons of waste treated at a solids content of 2.5-3%.125 Data related to the
ability of the Hansel process to remove dioxin consists of two tests, one where a river water sample at 16 ppq was
reduced to ND(5 ppq) and another were a effluent sample spiked to 326 ppq was reduced by 89%.123
Laboratory studies performed on total bleach plant waste where alum was used resulted in a COD reduction of 40-
60%, a BOD7 reduction of 25% and a reduction in TOC1 of 60-70%.'
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TABLE VII-5
LRP EFFLUENT TREATMENT RESULTS*4
TOTAL MILL EFFLUENT PERCENT REMOVAL
KRAFT SOFTWOOD KRAFT HARDWOOD
BOD7 0-20 0-20
COD "22-67 2(M1
Color 32-95 21-33
TOG 36-70 30-31
Chlorinated Phenols 50-59 32-44
Installations:
There are no known full scale applications of CAC on bleached pulp mill waste. CAC is, however, being used at
the Stone Container mill at Hodge, LA. In this application polyelectrolyte is being added to the effluent for color
removal.
Implementation:
Implementation of the LRP process consists of retrofitting an existing primary clarifier and involves installation of
chemical storage, piping, tanks, electrical controls and foundations for buildings.*4 The two most commonly
encountered problems with this technology are the amount of solids produced and the difficulties associated with
dewatering and disposal. No information was available as to the time needed for installation of a CAC system.
CoStS!
Costs for CAC are highly dependent on the amount of coagulants used and the amount of solids produced. The cost
of reagents for the Hansel process are reported as ranging between 120 and 220/1000 gallons of 1,200 PCU.125 The
costs for a 20 MGD facility are reported as follows: capital cost of $1.85 million, operating costs of $15/1000 gal,
$3,000/day or approximately $1.095 million/year and a price per ton of production of approximately S3.40.125.
These costs, however do not include sludge disposal. The costs for retrofitting a primary clarifier for the LRP
process based on a 400 Ton/day CTMP facility were reported as a capital cost of $370,000 and operation costs of
$520,000/yeat84 The operation costs include chemicals, power, sludge handling, analysis and control, and
maintenance.*4
*.
References:
1, 2, 27, 84, 125, 128
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ENHANCED PHOTOOXIDATION
Technology Description;
This process involves the use of ultraviolet light and hydrogen peroxide to oxidize hazardous and biorefractory
organic wastes. This is accomplished through the production of hydroxyl free radicals from ultraviolet light induced
decomposition of the hydrogen peroxide. The hydroxyl free radicals produced are highly reactive but are reported to
be non selective in that they oxidize recalcitrant molecules as easily as those that are biodegradable.209
Effectiveness:
Two trials of this process are reported in the literature, one on pine Eo filtrate at a South Carolina mill and the other
on a Canadian bleach plant effluent.203-203 AOX reductions were reported by one source to be from approximately
3.5-4.0 kg/tonne to 2.5 and l.,5 kg/tonne.205 Color removal was reported by one source to be greater than 98
percent (5000 PCU to <100 PCU) while a second source reported a color removal rate of 80 percent.203'205 One
distinct advantage of this process over other color treatment processes is that no sludge is generated.205
Installations;
There are no installations of this technology referenced in the literature reviewed.
Implementation;
The time required to implement this process was not provided in the literature reviewed.
Costs;
The capital cost associated with this process was estimated by one source to be approximately $8-9 million for an
800 tonne per day mill with an influent AOX of 4.5 kg/tonne and a treated effluent AOX of 2.5 kg/tonne205 The
operating cost was given as approximately $4.50/tonne of pulp produced.205 Another source stated that this
treatment process had an operating cost that was competitive with other color removal technologies.205
References;
203, 205
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BIOLOGICAL TREATMENT
AEROBIC TREATMENT
Technology Description:
Biological treatment is utilized for the treatment of pulp and paper wastewater due to the relative biodegradability of
most of the organic substances in the waste, with the exception of lignin. The most common biological treatment
used in the industry is aerobic treatment either in the form of aerated stabilization basins (ASB) or activated sludge.
ASBs or aerated lagoons are used all over the world and are common in Sweden and the US. In these systems
aeration is accomplished through mechanical surface aeration or through the use of diffused ait Retention times are
normally in the range of eight to ten days but are frequently up to IS days. The main advantages of ASBs are lower
energy requirements, lower operational attention required, lower capital cost where land costs are low, and good
equalization of hydraulic and organic loads. Activated sludge systems are similar to the ASB except that they treat-
the wastewater in a shorter period of time, usually being designed for four to eight hours of total retention.
Activated sludge systems are preferred to aerated lagoons in many countries due to the fact that they are more
compact and give a somewhat better and more uniform reduction on BOD and COD.35
Effectiveness!
Aerated biological treatment, especially activated sludge, has been shown to be effective in the removal of chlorinated
organic matter achieving AOX removals of 48-65% and chlorophenolics removals of 75-95%.77 Aerated
stabilization basin systems were also effective, but to a lesser degree achieving 32% removal of AOX and 54%
removal of chlorophenolics.77 The main reason(s) for this difference in efficiency is reported to be related to solids
retention time or to the fact that in aerated lagoon systems materials that are adsorbed onto the cells are liberated back
into the liquid phase when the cells decompose, while in the activated sludge systems the excess solids are removed
from the system.35 In another study conducted at a mill utilizing oxygen delignification the AOX reduction across
the ASB after seven days of detention was 56% achieving a final AOX level in the treated effluent of 1.28
kg/ADT.160 As a summary of removal efficiencies, Table VII-6 presents design criteria for four aerobic systems,
two ASBs and two activated sludge.
Little data exist to show what the removal efficiency of aerobic treatment systems is for 2378-TCDD and 2378-
TCDF. A preliminary comparison was made however of 2378-TCDD discharged from kraft mills with activated
sludge treatment and aerated stabilizations basins. On a mean basis, the concentration, mass, and mass per unit of
production of 2378-TCDD discharges are somewhat higher from mills with ASB treatment as shown in Figure
VII-1.
Installations:
At the present time 101 of 104 of the chemical pulp mills that bleach with chlorine utilize aerobic biological
treatment systems for the treatment for their wastewaters. Of these, approximately 50 percent utilize ASBs and 50
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0.18
0.15-
o
Q
o
I-
I
CO
I**
-------
Implementation: ^
The time required for installation of this technology is somewhat dependent on the choke of system employed with
activated sludge systems usually requiring more time than aerated stabilization basins. An appropriate time for
implementation of this technology would be two years. This figure is based on experience gained during the late
seventies when the majority of biological wastewater treatment systems in the industry were installed.
Costs:
Costs related to this technology were not found in the literature reviewed for this report but are readily available.
Recommended sources include the following: Treatability Manual Volume ££ Cost Estimating. Office of Research
and Development, U.S. Environmental Protection Agency, Washington, D.C., EPA-600/2-82-001d, April 1983
(Revised) and Development Document For Effluent Limitations Guidelines (BPCTCA) la ifae. Bleached Kraft.
Groundwood. Sulfite. S.oda. Deink and Non-intregrated Paper Mills Segment of the Pulp. Paper, and Paperboard
Point Source Category. U.S. Environmental Protection Agency, Washington, D.C., EPA 440/1 -76/047-b, December
1976.
References!
7, 27, 35, 37, 73, 76, 77, 84,93,101,102, 121,127, 160, 175, 178,180,184,193
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ANAEROBIC TREATMENT
Technology Description:
Biological treatment of organic wastes can take place in anaerobic (oxygen-free) conditions. Such conditions can
take place in deposited sludge at the bottom of aerated lagoons. Anaerobic systems are based on the production of
anaerobic bacteria, anaerobes, which grow slower and require less energy and nutrients than aerobic bacteria. End
products of anaerobic decomposition includes methane gas and water. Advantages of anaerobic over aerobic treatment
are that less sludge is produced, little energy is required to run the system and energy in the form of the methane gas
is produced
Effectiveness; x
Anaerobic degradation and dehalogenation of low molecular chlorinated organics has been known for some time and
is reported in the literature.35 One study of anaerobic treatment of bleach plant waste reported 70-90% removal of
chlorophenols, 70-90% removal of chloroform and 20-30% removal of TOG at a hydraulic loading of 3.5m3/m3 of
reactor/day.35 This degree of TOG removal, which was achieved in seven hours, was reported as the same as that
achieved in an aerobic treatment system in seven days.M In another study, permeate from ultrafiltration of El-stage
filtrate was added to the C/D filtrate and treated anaerobically. AOX was reduced from 92 mg/1 to 67 mg/1 (27%
removal) with a retention time of one hour and from 92 mg/1 to 42 mg/1 (54% removal) with a retention time of 24
hours.35
Installations;
Several anaerobic wastewater treatment systems are in operation in the pulp and paper industry with the majority at
sulfate and CTMP facilities. Two ENSO-FENOX system are reported in operation in Finland treating bleach plant
effluents.35
Implementation:
Anaerobic systems need aerobic systems to polish the wastes prior to discharge. Anaerobic systems tend to work
best on concentrated wastes as high biological solids levels are needed to obtain good organic removals. If a dilute
waste is treated, the problem becomes keeping the solids in the reactor from being washed out of the system. The
reason why anaerobic systems have not been utilized more in the kraft pulping industry stems from the fact that the
few waste streams that are organically concentrated enough to treat anaerobically tend to exhibit toxicity toward the
anaerobic organisms.
Costs:
No information was available in the literature reviewed related to costs for anaerobic systems.
-83-
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7,21,35,85,116, 142,163
-84-
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ATTACHMENT A
REFERENCES
-85-
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
Treatment Of Effluents From The
Pulp And Paper Industry By
Chemical Coagulation
Almemark, M.; Eriksson, G.;
Hagerstedt, L.-E.
TAPPI Seminar Proceedings.
Bleaching and the Environment,
Seattle, Washington. September
1988. pp. 251-272.
This paper deals with chemical coagulation of bleach plant effluents with alum
followed by incineration of the sludge and acid recovery of the coagulants. Costs
are projected for full scale operation.
2. Bench Scale Study of Dioxins and
Furan (2378-TCDD and 2378-TCDF)
Treatability in Pulp and Paper Mill
Wastewaters
Amendola, G.A.; Bodien, D.G.;
Handy. R.BJr.
TAPPI Journal. December 1989. pp.
189-194.
The principal objectives of this study were to determine the solid and liquid phase
distribution of 2378-TCDD and 2378-TCDF in untreated, partially treated and
treated process wastewaters from pulp and paper mills; and to determine whether
chemically assisted clarification (CAC) might be a feasible alternative for
removing those compounds from internal mill and total mill process wastewaler.
Results of bench scale studies indicate that from 30% to 40% of the 2378-TCDD and
2378-TCDF is present in the solid phases of internal mill samples; greater than
90% in aeration basin effluents; and from 40% to 75% in final effluents. CAC
proved to be effective at removing 2378-TCDD and 2378-TCDF from internal mill
wastewaters, however, less cost effective than providing improved treatment in
existing secondary treatment facilities.
3. On-line Oxygen Delignification
Control
Anon.
TAPPWCPPA Proceedings. 1988
International Pulp Bleaching
Conference, Orlando, Florida, June
1988.
Discussion of control system for oxygen delignification based on on-line Kappa
number measurement. System reduced average Kappa number and production costs.
4. P & P's Annual Bleaching Survey: Ducey, M.J., Technical Editor
Capital Expenditures Increasing
Pulp & Paper, June 1988. pp. 72-75.
General summary of capital expenditures in bleached pulp mills, chlorine dioxide
substitution, oxygen delignificalion, and process control are a big part of capital
expenditures.
5. Oxygen Bleaching of Kraft Pulp: Idner, K.
High Consistency vs. Medium
Consistency
TAPPI Journal, February 1988. pp.
47-50.
A comparison between conventional high-consistency bleaching and
medium-consistency oxygen bleaching is reported. Associated pulp viscosity and
Kappa number, costs, and environmental effects are provided.
Extended Delignification, An
Alternative To Conventional Kraft
Pulping
Mera. F.E.; Chamberlin. J.L.
TAPPI Journal, January 1987. pp.
132-136.
Mill and pilot plant data for market grade bleached pulp were evaluated. The pulp
quality was equivalent to or better than that of bleached pulps obtained by
conventional kraft pulping and bleaching techniques. However, operating
parameters favored extended cooking in the rapid displacement heating process.
These parameters were lower active alkali consumption, lower bleaching chemical
demand, and lower bleach plant effluent liability.
-------
ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
7. BioMMption Of Organic Halide In
Kraft Mill Generated Lagoon
Amy. G.L.; Bryant. C.W.; Alleman.
B.C.; Barkley. W.A.
Journal WPCF, August 1988. pp.
1445-1453.
Kraft mill wastewaler contains substantial concentrations of both total organic
halide (TOX) and low molecular weight (less than 1000 g) TOX as a consequence of
chlorine bleaching activities. An aerated lagoon removes from one-third to on-half
of both these fractions of organic halide. Indirect evidence suggests that anaerobic
degradation and dehalogenalion occur in the benthal layer of the lagoon. Sorption
onto settling biomass is the mechanism required for transport to the benthal layer.
Aerobic biomass is capable of adsorbing both high and low molecular weight TOX;
adsorption is affected by pH, temperature, cell age, and cell viability.
8. Oxygen Bleaching Practices And
Benefits - An Overview
Tench, L.; Harper. S.
TAPPI Proceedings, 1987
International Oxygen
Delignificalion Conference.
A list of the world-wide oxygen delignificalion installations and a summary of the
experience gained to date are presented. Pulp quality, environmental benefits,
chemical savings, the impact on recovery and energy consumption, high vs.
medium consistency delignificalion and washing and screening considerations are
discussed.
9. Reactions of Nitrated Kraft LJgnin in Lindeberg, O.; Walding, J.
an Alkaline Oxygen Bleaching
State
TAPPI Journal, October 1987. pp.
119-123.
Discussion on pretreatment of kraft pulp with NO2/O2 prior to oxygen bleaching
and resulting chemical and selectivity effects.
10. PRENOX® Process-Experiences Simonson, O.; Lindstrom. L.-A.;
from a Pilot Plant Installation, The Marklund, A.
TAPPI Journal, August 1987, pp.
73-76.
Study showing that high-consistency treatment of pulp with NO2 and O2 before the
oxygen delignificalion stage can produce pulp with a kappa number of 7 and
significantly reduce bleach-plant pollutants.
11. Oxygen Bleaching'* Pace Quickens McDonough, TJ.
TAPPI Journal, August 1987, pp.
125-127.
General overview of discussions that occurred at the first International Oxygen
Delignificalion Conference, June 7-12. 1987. San Diego, California.
12. RDH Kraft Pulping to Extend
Delignification. Decrease Effluent,
and Improve Productivity and Pulp
Properties
Andrews. E.K.
TAPPI Journal, November 1989. pp.
55-61.
Rapid displacement heating kraft pulping impacts on pulp bleachability and
bleach plant effluent described in combination with brownslock oxygen
delignification.
13. Underchlorination Can Become
Inadequate Medicine
Annergren. G.E.; lindblad. P.-O.;
Norden, S.
Svensk Papperstidning, November
12, 1987, pp. 29-32.
Underchlorination was in earlier limes something negative and regarded clearly as
harmful for pulp. The technical development has however waited to be
understood-today Underchlorination is something to strive for, not the least from
the environmental standpoint. This paper discusses the studies of reduced chlorine
usage on pulp properties.
14. North America's First Fully Enz. S.M.; Emmerling, F.A.
Integrated, Medium Consistency
Oxygen Delignification Stage
TAPPI Journal. June 1987, pp.
105-112.
Consolidated Papers Inc. has installed a medium-consistency oxygen
delignification reactor in the hardwood pulp line at its kraft mill in Wisconsin
Rapids, Wisconsin. System has resulted in a decrease in kappa number, increased
production and brightness and a decrease in chemical consumption.
-------
ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
15. Effect Of Prebleaching Conditions
On The Performance Of Short
Sequences For Oxygen Bleached
KiaftPulp
Annergren. G.E.; lindstrom, L.-A.;
LJndblad, P.-O.; Noiden, S.
TAPPI/CPPA Proceedings. 1988
International Pulp Bleaching
Conference, Orlando, Florida, June
1988, pp. 37-46.
Important prebleaching conditions have been studied for short sequence bleaching
both in the laboratory and in mills. The studies concerned mainly oxygen bleached
kraft pulp but certain comparisons have been made with unbleached kraft pulp.
There were two reasons for dealing with prebleaching in this case. A short sequence
gives higher weighting to each stage which calls for a particular optimization of
the prebleaching. On the other hand, environmental concerns aim at a low
formation of chlorinated organics through a reduced chlorination. The general
opinion is that a high chemical charge is required in the chlorination of a short
sequence. However, our results indicate that this is not true for normal levels of
final brightness and that commercial operation with a substantial restricted
chlorination is possible. The reinforcement of the alkaline extraction is very
important in this context.
16. Pulping Bleaching Concerns Focus
on C1O2 Generation, Effluent
Ducey, M.J., Technical Editor
Pulp A Paper. June 1987, pp. 89-92.
Article takes a comprehensive look at the current mill chemical consumption
patterns, new supplier products and their markets and the latest developments from
a number of North American research institutions, and provides some brief facts on
worldwide chemical pulp production and growth over the past 12 months.
17. Minimizing the Formation of
Chlorinated Organic Material
Through Controlled Chlorination in
the Production of High Quality
Softwood Kraft Pulp
Annergren, G.E.; Rees-Andersson,
A.-M.; Lindblad. P.O.; McKague, B.;
Stromberg, LM.; Kringstad, K.P.
TAPPI Proceedings. 1987
Environmental Conference,
Portland, Oregon, April 1987, pp.
313-318.
Spent liquors from the chlorinalion and alkali extraction of an oxygen prebleached
softwood kraft pulp were investigated with respect to environmental parameters
such as TOCI, chlorinated phenolic compounds some of which are lipophilic,
other lipophilic compounds and mutagenicity. The results show that the
parameters vary considerably with variations in the chlorine ratio and that
therefore possibilities exist to minimize chlorinated organic compounds through
controlling the chlorination.
18. Laboratory Studies of Chloroform
Formation in Pulp Bleaching
Crawford, R.J.; Stryker, M.N.; Jett,
S.W.; Carpenter, W.L.; Fisher. R.P.;
Jam. A.K.
TAPPI Proceedings. 1987 Pulping
Conference, pp. 113-118.
The effects of C, E, and H stage bleaching parameters on chloroform production
have been investigated in the laboratory for both softwood and hardwood kraft
pulp*. D stage chloroform production has been shown to be minimal. The H stage
was found to be the largest chloroform producer.
19. Improvement Of Bleach Plant
Effluent By Cutting Back On 02
Axegard, P.
TAPPI/CPPA Proceedings, 1988
International Pulp Bleaching
Conference. Orlando. Florida, June
1988. p. 69.
The consumption of C12 has been studied over a large range in a mill trial and in the
laboratory. The results were evaluated for AOX, TOO. EOC1. chloroform and
chlorinated phenolics in the filtrate and as chlorodioxins and furans in the pulp.
AOX and TOCI are reduced linearly with a decreased consumption of the elemental
chlorine in C12 and C1O2. The ratio between AOX and TOCI is not constant which
makes it difficult to translate a TOCI-value to an AOX-value. Chlorinated phenolics
were found to be affected only by the Q2-consumption. Below about 10 kg C12 ptp
virtually no highly chlorinated phenolics could be found.
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
20. Effect of Chlorine Dioxide
Substitution on Bleaching
Efficiency »nd the Formation of
Organically Bound Chlorine - Part
0
Axegard, P.
Journal of Pulp and Paper Science,
1986.
21. Technical and Economic Aspects of
Measures to Reduce Water Pollution
caused by the Discharges from the
Pulp and Paper Industry, The
COWIconsult
EEC-Contract B6612-551-88 Final
Report, November 1989.
The report is a study of the technical and economical aspects of measures to reduce
water pollution caused by ihe discharges of the pulp and paper industry. It is
intended to be a development document for a future EEC Directive regulating
aqueous discharges from this industry.
22. Chlorine Dioxide Substitution Axegard, P.
Reduces the Load of TOO
TAPPI Proceedings. 1987 Pulping
Conference. November 1987, pp.
105-110.
Laboratory bleaching experiments have been carried out on an industrial oxygen
delignified softwood kraft pulp at different C1O2 - substitution levels. Parameters
studied were prebleaching efficiency, final brightness, formation of chlorate as
well as chlorinated organics. The formation of TOCI. EOC1. AOX. highly
chlorinated phenolic* and chloroforms is reduced with reduced C12 consumption.
23. Influence Of Bleaching Chemicals
And LJgnin Content On The
Formation Of Polychlorinated
Dioxins And Dibenzofurans, The
Axegard, P.; Renberg, L.
Chemosphere, (Dioxin 88)
The determination of chlorinated dibenzo-p-dioxins and dibenzofurans in pulp and
aqueous filtrate from pulp bleaching showed that the most important variable is the
consumption of molecular chlorine (C12) expressed as Ihe ratio between chlorine
and the lignin content (C12-multiplc). The formation of the dioxins and
dibenzofurans increased drastically above a certain critical level and below this
level the formation! were very low. No significant difference between oxygen
delignified and non-oxygen delignified softwood kraft pulp could be established.
24. Results of On-Site Pilot Plant
Studies of the SLC® Extraction
Process
Elton. E.F.; Parkinson, J.R.
TAPPI Proceedings. 1987 Pulping
Conference, pp. 673-678.
The SLC® (suppressed lignin condensation) extraction process was pilot tested on
hardwood and softwood kraft pulp in two separate mills. Reported results were
decreased CEK No and decreased steam, hypochlorite (47%), and chlorine (10%)
usage.
25. Use of Hypolite Bleach in Short
Sequence Pulp Bleaching, The
Hurst, MM.; Stunk, T.S.; Duff, A.
TAPPI Proceedings, 1987 Pulping
Conference, pp. 15-19.
Paper discusses brightness, viscosity and chloroform formation when replacing
peroxide or hypochlorite with hypolile bleach, during pulp bleaching.
26. Substituting Chlorine Dioxide For
Elemental Chlorine Makes The
Bleach Plant Effluent Less Toxic
Axegard. P.
TAPPI Journal, October 1986. pp.
54-59.
A full-scale mill trial shows there are two principal ways of reducing the
consumption of elemental chlorine by using more chlorine dioxide when bleaching
to full brightness. The methods used were "high substitution" and "low multiple."
The formation of TOCI, EOC1 and chlorinated acetic acids were found to decrease
lineally with chlorine consumption.
27. Screening Study of the Treatability Barton. D.A.; McKeown, JJ.;
of Dioxins and Furans in Bleach Brunck, R.A.
Plant Filtrates and Mill Wastewaters
NCASI 1989 West Coast Regional
Meeting, October 4, 1989.
Unpublished report consists of tables used for presentation at NCASI 1989 West
Coast Regional Meeting.
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
28. Reinforcement of Oxygen-Alkali
Extraction with Hydrogen Peroxide
or Hypochlorile
Lichenal. D.; de Choudens, C;
Bourion, L.
TAPPI Journal. July 1986. pp.
90-93.
Small amounts of hydrogen peroxide or hypochlorile were added in the oxygen
extraction stage of various bleaching sequences. The effects on viscosity and
brightness are presented.
29. Efforts in Chemical Pulp Bleaching Ducey, M.J.. Technical Editor
Technology Emphasize Cutting
Costs
Pulp & Paper. July 1986, pp. 47-50.
Article presents a summary of Pulp & Paper's third annual survey of bleaching
equipment. Finds fewer new systems; emphasis is on washing, process control,
chemical additions. Oxygen delignificalion is the number one choice of mills
installing new systems.
30. Curtailing Dioxin
Formation -Ramifications for
Chemical Pulp Bleaching
Berry, R.M.; et al.
31- Oxygen Bleaching Processes McDonough, TJ.
Dioxin '89, September 1989
TAPPI Journal, June 1986. pp.
46-52.
Paper discusses many aspects of oxygen delignification, high and medium
consistency, selectivity and protectors, pretrealment with nitrogen oxides, and
process fundamentals. Also discusses oxygen extraction and low-pressure oxygen
bleaching.
32. Complete Effluent Recycling in the Dorics, J.; Wong, A.; Gamer, B.C.
Bleach Plant with Ullrafillration and
Reverse Osmosis
TAPPI Proceedings, 1985 Pulping
Conference, p. 590.
A membrane filtration process was studied for the treatment of bleach plant
effluents using ultrafiltrauon and reverse osmosis. The objective was removal of
color, organic compounds, and chloride ions. The filtration process design and
costs are presented.
33. Toward Preventing The Formation Berry, R.M.; Fleming, B.I.; Voss,
Of Dioxins During Chemical Pulp R.H. Luthe, C.E.; Wrist, P.E
Bleaching
Pulp & Paper Canada. 90(8). 1989.
pp. 48-58.
Suitable combinations of chlorine multiple and CLO2 substitution which lead to
low or undeiectable levels of TCDD and TCDF have been identified. Adding
chlorine to pulp in advance of chlorine dioxide has been found to be more effective
than the reverse mode of addition for reduction of chlorinated dioxins and furans.
Increasing the C-stage pH and decreasing its consistency also appears to be
beneficial. Minimizing the levels of the precursors, dibenzodioxin (DBD) and
dibenzofuran (DBF), was confirmed as being important for curtailing TCDD and
TCDF formation. In particular, oxygen delignification was found to be
advantageous, not because it removes lignin but because it decreases the precursor
levels.
34. Ozone Dclignif ication of Black
Spruce and Hardwood Kraft,
Knft-Anthnquinone, and
Soda-Anthraquinone Pulps
Liebergott, N.; van Lierop, B.
TAPPI Journal. June 1981. pp.
95-99.
After ozone delignificalion followed by DED treatment, black spruce, and mixed
hardwood kraft, kraft-AQ and soda-AQ pulps attained 89-92% brightness (ISO) and
compared to conventionally bleached CEDED pulps, required less C1O2 in the third
and fifth stages, had somewhat lower strength properties for black spruce but
similar strength for hardwood pulps, and gave effluents and color loadings that
were 60-75% lower.
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
35. Some Aspects On Biological
Treatment Of Bleached Pulp
Effluents
Boman, B.; Frostell. B.; Ek. M.;
Eriksson. K.-E.
Nordic Pulp and Paper Research
Journal. 1-1988 . pp. 13-18.
The article describes the most important methods presently used for external
treatment of bleach plant effluents. They are in most cases designed to reduce BOD
and are not very effective in reducing AOX. None of the biological methods
currently used can degrade high molecular mass material. The possibility of using
special fungi, able to attack the high molecular mass chlorinated lignins, is
discussed. Anaerobic dechlorination is also mentioned. A combination of
physical/chemical methods and biological treatment is proposed for the
development of new purification processes. A combined process with
ultrafiltration and effective biological treatment is estimated to give at least 95%
reduction of BOD and 70-90% reduction of COD and AOX.
36. Oxidation Of Pulp With NO2/O2
Prior To Oxygen Delignification - A
Novel Process With Potentially
Leu Pollution
Bnnnland, R.; Luidstrom, L.-A.;
Norden, S.; Simonson, O.
TAPPI Proceedings. 1985
International Bleaching
Conference.
Four companies AGA, KemaNord, MoDo and Sunds Defibrator are jointly
exploring a new delignification process. With this process, characterized by a
pretreatmenl of pulp prior to oxygen delignification with a combination of NO2 and
O2 it is possible to delignify softwood kraft pulp to kappa numbers below 10. In
this paper we will discuss what impact this process will have on chemical
composition and environmental effects of spent liquors produced in a subsequent
bleaching process. Results will be compared with those from bleaching of oxygen
delignified pulp. Also matters related to working environment and emission to air
will be covered.
37. Organic Halide In Kraft Mill Bryant. C.W.; Amy. G.L.
Wastewaters: Factors Affecting
In-mill Formation And Removal By
Biological Treatment
TAPPI Proceedings. 1988
Environmental Conference, pp.
435-438.
Chlorine is used as a pulp bleaching agent, resulting in the formation of various
organochlorine compounds that range from simple chlorophenols to higher
molecular weight chlorolignin compounds. In addition to persisting in the
environment, some of these compounds exhibit toxicity or mutagenicity. Recent
work has focused on the use of the total organic halide (TOX) parameter for
measuring the totality of these compounds.
38. Oxidative Bleaching - A Review. Uebergott. N.; van Lierop, B.
Parti: Delignification
Pulp A Paper Canada, September
1986. pp. 58-62.
Literature relating to the use of oxidative chemicals in the delignification and
brightening operations of pulp bleaching is reviewed. Experimental data on the
use of oxygen, ozone and chlorine dioxide in the chlorinalion stage and
hypochlorite, peroxide and oxygen in the extraction stages are also presented.
39. Factors That Affect The Generation Crawford, R.J.; Stryker, M.N.
Of Chloroform In Bleaching
TAPPI Journal, November 1988,
pp. 151-159.
Bleachery filtrate mixing and pH adjustment in the mill effluent treatment system
affect the formation of chloroform. In laboratory experiments, the pH adjustment
of chlorination-stage filtrate resulted in chloroform increases of up to 20 times the
original concentration. Laboratory and field experiments at a bleached kraft mill
indicate that the magnitude of chloroform generated through this process will
depend on the specific bleaching conditions in the chlorinalion stage and on the
pH of the combined mill sewer. In some cases, this effect may account for a
significant fraction of the chloroform in the influent to wastewater treatment
system.
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
40- Influence Of Chlorine Ratio And
Oxygen Bleaching On The
Formation Of PCDFi And PCDDs In
Pulp Bleaching, Pan 1: A
Laboratory Study
de Souia, R; Kolar, M.-C.;
Kringstad, K.P.; Swanton. S.E.,
Rappe, C; Glai. B.
TAPPI Journal. April 1989. pp.
147-152.
In a laboratory bleaching itudy, we assessed the influence of the chlorine ratio and
oxygen bleaching on the amounts of polychlorinated dibenzofurans (PCDFs) and
polychlorinated dibenzo-p-dioxin (PCDDs) formed. A significant factor affecting
the amounts of PCDF and PCDD is the chlorine ratio. On well-washed laboratory
pulp, oxygen bleaching has little or no effect. The beneficial effects of oxygen
bleaching on the amounts of PCDFs and PCDDs observed in mill-scale studies is
therefore likely the result of the much greater efficiency in pulp washing through
the oxygen bleaching stage.
41. Worldwide E Installations Survey, A Reeve, D.W.
TAPPI Journal. November 1985, pp.
142-143.
World wide survey of Eo (use of oxygen in the extraction stage of chemical pulp
bleaching) installations.
42. Fraternity Gathers at the Chateau:
The 1985 International Pulp
Bleaching Conference
Pryke, D.C.
TAPPI Journal, August 1985. pp.
145-147.
Overview of general subjects discussed during the conference. Major topics were
chlorine-free processes, importance of mixing, oxidation extraction, chlorine
dioxide bleaching, and the future of bleaching.
43. Delignifying High-Yield Pulps
With Oxygen and Alkali
Kleppe, P.J.; Storebraten S.
TAPPI Journal, July 1985. pp.
68-73.
Discussion of delignifying high-yield pulps with oxygen and alkali by using a two
stage pulping process. Pulp properties, sack paper production and linerboard
production are discussed.
44. Paper Industry Consumption of
C1O2 Soars as Available Supply
Tightens
Downs, T. Technical Editor
Pulp A Paper, October 1989, pp.
111-112.
Article discusses trend toward high chlorine dioxide substitution, anticipated
supply problems and part this substitution plays in meeting anticipated
requirements.
45. The Future of Bleaching
Reeve. D.W.
TAPPI Journal. June 1985. pp.
34-37.
Summary of what is taking place in bleaching, what are the economic influences
and what is predicted to happen in the near future.
46. Chlorinated Organic Matter in Earl. P.P.; Reeve, D.W.
Bleached Chemical Pulp Production:
Part III -The effect of QUorination
Stage Variables on Chlorinated
Organic Matter in Effluents
TAPPI Journal. October 1989. pp.
183-187.
Softwood kraft pulps were chlorinated at low and medium consistency in the
laboratory, covering a wide range of chlorination levels, wilh and without chlorine
dioxide substitution. The filtrates from the chlorinalion and extraction stages were
analyzed for AOX and BOX. AOX formation decreased when mixing was improved,
but BOX was unchanged. At 50% C1O2 substitution AOX formation fell by 40%.
Equations were developed to estimate the amount of AOX and EOX formed, based on
the elemental chlorine in the oxidant consumed by the pulp.
47. Chlorinated Organic Matter in Earl, P.F.; Reeve, D.W.
Bleached Chemical Pulp Production:
Part VI - Chlorinated Compounds in
Effluents
TAPPI Journal, January 1990, pp.
179-184.
Fifty percent C1O2 substitution significantly decreased the total amount of
chlorinated phenolic compounds and the amount of letrachlorinated phenolic
compounds in chlorination and extraction stage effluents. Improved chlorinalion
stage mixing also decreased the formation of letrachlorinated phenolic compounds
significantly. Chloroform formation in the chlorination stage was decreased by
improved mixing, by increased consistency and by 50% C1O2 substitution.
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
48. Bo LuulUlioni Survey
Reeve. D.W.
TAPPI Journal. October 1984. pp.
110-111.
SYNOPSIS '
World wide lummiry of oxygen delignificalion (EO), processes instilled. Dramatic
growth in EO installations is reported.
49. Oxygen Delignification Systems: Edwards, L.; Myer, M.; Haynes. 1.
Optimum Design Syntheses
TAPPI Seminar Proceedings.
Bleaching and the Environment,
Seattle, Washington, September
1988. pp. 333-356.
Simulation and optimization techniques are used to determine the best
combination of equipment and operating conditions from an oxygen
delignificalion system including washing. Both capital costs and operating costs
are considered. For example, "What is the optimum dilution factor and amount of
washing equipment and how should the equipment be divided between pre- and
post-oxygen stage washing?" Evaporator and environmental constraints are also
taken into account.
SO. Oxidative Extraction « Halsey Mill Ducey, M.J.. Technical Editor
Cot* Hypochlorite Consumption
Pulp A Paper, October 1984. pp.
118-119.
Discussion of how an Oxidative Extraction System having a high-shear
mechanical mixer repaid its capital costs within one year. System installation
considered a success.
51. Some Bleach Plant Modification To Edwards. L; Myers. M.; McKean. B.
Reduce The Amount Of Toxic
Substances In Pulp And Filtrate
TAPPI Seminar Proceedings,
Bleaching and the Environment,
Seattle, Washington, September
1988, pp. 328-332.
This report discusses the benefits of increasing the amount of lignin removed from
the brownstock pulp through more efficient washing.
52. Consultants View On The European
Environmental Requirements And
Enforcement Activities Related To
Aqueous Discharges From The Pulp
And Paper Industry, A
Folke. J.
Cooperation on environmental issues in Europe is performed by means of more
than 20 organizational bodies ranging from well-known international
organizations to a number of conventions ratified individually by slate
governments. This paper discusses some of the problems that have to be considered
when issuing wastewater discharge permits to the pulp and paper industry,
including the choice of parameters to regulate the discharge of chlorinated matter
and dioxins, chemical balances in pulp bleaching, and the question of energy,
entropy and environmental protection.
53. Tutorial - Non-chlorine Bleaching Liebergott. N.; van Lierop, B.;
Of Chemical Pulp Gamer, B.C.; Kubes. G J.
TAPPI Proceedings, 1987
Environmental Conference, pp.
303-312.
Two bleaching sequences were developed for a kraft pulp (kappa # 30.6) that avoid
chlorine-containing compounds by using only oxygen (O), ozone (Z). sodium
hydroxide (E). hydrogen peroxide (P) and sodium hydrosulphile (Y). Effluents were
40-60% lower in colour than those obtained from a conventional C/DEDED
sequence. The oxygen stage may be done at medium (7%) or high (25%)
consistency. After the sequence OZEP. the pulps had a brightness of 80-86% ISO.
In the sequence ZOP. the final brightness could be improved by 10 points if the ZO
bleached pulps were washed with effluent from the Z stage. Semi-bleached pulps
from both sequences achieved a brightness of 88-90% on final-stage bleaching
with hydrosulphile. The strength properties of pulps bleached by these novel
sequences and by conventional C/DEDED. OZEPY and ZOPY sequences was
evaluated.
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
54. Pretrealment Of Kraft Pulp Is The Fonum, G.; Mirklund, A.
Key To E«y Final Bleaching
TAPPI Journal. November 1988. pp.
79-84.
Low values of total organic chlorine (O.S kg/metric ton) were reached with a
combination of extended delignification to kappa numbers below 10 and a high
chlorine dioxide fraction in the prebleaching.
55. Final Bleaching of Kraft Pulps Fossum, G.; Lindqvijl, B.; Persson,
Delignified to Low Kappa Number L-B.
by Oxygen Bleaching
TAPPI Journal. December 1983. pp.
60-62.
Discussing of prelrealmenl kraft pulp with nitrogen dioxide and oxygen prior to
oxygen bleaching, Chemical demand, pulp viscosity, strength and yield and
bleach effluents from pretreated sequence is compared to conventional oxygen
bleaching.
56. How Bleaching Hardwood Kraft Pulp Jones, A.R.
with Oxygen Affect* the
Environment
TAPPI Journal, December 1983, pp.
42-43.
Article provides short explanation of conventional and oxygen bleaching
sequences and compares effluent volume, color and BOD from the two processes.
57. Short Sequence Bleaching with
Oxygen: PartD
Schleinkofer, R.W.
TAPPI Proceedings. 1982 Pulping
Conference, pp. 303-308.
Laboratory bleaching data from the sequences C/D-E-D-E-D, O-C/D-E-D,
C/D E-Eo-D, O-C/D-Eo-D, and C/D-Eo-D-E-D are compared for two softwood kraft
pulps. Costs, Kappa No., viscosity, brightness, energy consumption, and effluent
properties are compared.
58. Automated C1O2 Generation
Improves Bleaching, Cuts Effluent
Evans, J.C.W.. Senior Editor
Pulp A Paper, February 1983, pp.
69-71.
Discussion of continuous monitoring and control for a chlorine dioxide generator.
59. Technical Consequences of New
Knowledge on Prebleaching with a
High Fraction of Chlorine Dioxide
Germgard, U.
TAPPI Journal, December 1982, pp.
81-83.
Prebleaching of softwood kraft pulp with chlorine dioxide and low fraction of
chlorine has been studied in the laboratory under well-controlled bleaching
conditions. This paper concentrates on the influence of the chlorine fraction and of
a preceding oxygen bleaching stage. The technical consequences are discussed,
particularly for the case where an oxygen bleaching stage precedes a pure chlorine
dioxide prebleaching stage.
60. Oxygen Bleaching System
Operating Well at Union Camp's
Franklin Mill
Smith, K.E., Executive Editor
Pulp A Paper. October 1982, pp.
90-93.
Overview of oxygen bleaching system at Union Camp's Franklin mill. Process is a
four stage OC/DED sequence reporting a reduced chemical and water usage and
improved effluent treatment
61. Bleaching Technology Review:
Recent Developments, Future
Tieads
Macleod, M.
Pulp A Paper. October 1982, pp.
61-65.
Discussion of chlorinalion issues, chlorine free bleaching, sequence
modifications, optimizing sequences without oxygen and displacement bleaching.
and closed cycle systems. Total organic chloride generated by various sequences is
presented.
62. Relative Rates of Consumption of
Chlorine and Chlorine Dioxide
During (D + C) Bleaching of
Softwood Kraft Pulp. The
Germgard, U.; Teder, A.; Tormund, D.
TAPPI Journal, May 1982. pp.
124-126.
Experiment presenting the relationship between consumption of chlorine dioxide
and chlorine during (DAC) bleaching.
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGAN1CS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
63. Short Sequence Bleaching With
Oxygen: Part I
Schleinkofer, R.W.
Pulp & Paper Canada. 83:11 (1982)
Two unbleached kraft pulp samples, one hardwood and one softwood, produced by
two eastern Canadian mills, were bleached in the laboratory by the sequences
C/DEDED. OC/DED and OC/DEoD. Fully bleached pulps of 90 ISO brightness were
obtained with the sequence OC/DEoD at substantial savings in chemical cost
compared to sequence C/DEDED. and strength properties were almost identical.
Energy balances show very small differences in net steam and power demand.
64. Oxygen Delignification
Technology: State-of-ihe-Art
Report on Advances
White. F.
Paper Trade Journal, February 28,
1982. pp. 27-30.
Oxygen and ozone delignificalion in the bleaching of kraft pulps are compared.
Medium consistency oxygen delignification of kraft pulp is described. Aspects of
low cost peroxide bleaching to high brightness are covered, and hydrogen
peroxide in chemical pulp bleaching is discussed.
65. System Using Medium-Consistency Nasman, L.E.
Oxygen Bleaching Works in
Sweden. A
Pulp & Paper. October 1981, pp.
137-138.
SCA mill at Ostrand has successfully run a full-scale oxygen-caustic extraction
stage. The advantages of oxygen plus oxygen-extraction stage are described.
66. Oxygen Delignification at Medium Markham, L.D.; Magnolia. V.L.
Consistency Can Raise Yield, Cut
BOD
Pulp A. Paper, October 1981, pp.
139-142.
General discussion of oxygen delignification including advantages and
disadvantages, process, pulp yield and effluent reduction.
67. Investigation for Presence of
PCDDs and PCDFs in Bleaching
Process from Pulp & Paper Industries
Fouquet, A.; et al.
Dioxin '89, September 1989
68. Developments in Chlorine Dioxide Reeve, D.W.; Rapion, W.H.
Bleaching
TAPPI Journal. September 1981,
pp. 141-143.
Discussion of increased replacement of chlorine by chlorine dioxide in the first
stage, Dc-C serial bleaching, and chlorine in chlorine dioxide bleaching. A
comparison of bleaching sequences with respect to chemical usage, energy
required, and inflation of chemical and energy cost* is provided.
69. New Opportunities for In-Plant
Reduction of Pollutants Through
Process Changes
Renard, J.J.; Phillips, R.B.; Jameel,
H.; Rudie, A.W.
TAPPI Journal. August 1981. pp.
51-54.
Four process options- medium-consistency oxygen delignification,
low-kappa-number kraft/AQ pulping, chlorine dioxide substitution, and caustic
extraction in the presence of oxygen (Eo stage) - were compared in terms of
production cost, environmental impact, and product quality. The oxygen-based
options were identified as the most cost effective options to reduce the pollution
load of a bleached kraft mill through process modification.
70. Oxygen/Alkali Delignification at Kleppe. P.J.; Knuuen. P.C.;
Medium Consistency Jacobsen, F.
TAPPI Journal. June 1981. pp.
87-90.
The sequence of events leading to the development of a mill-scale oxygen/alkali
delignification process at medium consistency is described. The process, which
takes pulp directly from the blow line of a continuous digester, is also presented.
The mill in the M. Peterson & Son mill in Moss, Norway.
10
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
71. Evaluation of Measures to Control
Chlorinated Dioxin and Fuian
Formation and Release at Bleached
Chemical Pulp Mills. An
Halliburton. D.; Chung, A.
Dioxin '89, September 1989
72. Kraft Mill Bleach Plant Effluents:
Recent Developments Aimed At
Decreasing Their Environmental
Impact. Pan 1
Heimburger, S.A.; Blevins. D.S.;
Bottwick, J.H.; Donnini. G.P.
TAPP1 Journal. October 1988. pp.
51-59.
A review of developments in the technology of pulping and bleaching has
demonstrated new ways to decrease the formation of chlorinated organic materials.
A review of the composition of bleach plant effluents and al effluent treatment
methods was also studied.
73. Kraft Mil] Bleach Plant Effluents:
Recent Developments Aimed At
Decreasing Their Environmental
Impact, Pan 2
Heimburger, S.A.; Blevins, D.S.;
Bottwick, J.H.; Donnini. G.P.
TAPPI Journal. November 1988, pp.
69-78.
In Part 1. processes that reduce the chemical demand of pulp by lowering the kappa
number prior to bleaching were investigated. These methods included extended
delignification and oxygen delignification. In Pan 2, other approaches such as
chlorine dioxide substitution, oxygen extraction, hydrogen peroxide
reinforcement, ozone and alternative bleach schemes without chlorine are
examined. Treatment methods including biological and physical/chemical are also
investigated.
74. Medium-Consistency Oxygen
Bleaching - An Alternative to the
High-Consistency Process
Nasman, L.E. ; Annergren, G.E.
TAPPI Journal. April 1980.
Medium-consistency oxygen bleaching has been examined both in the laboratory
and on a pilot-plant scale and has been found to give very encouraging results in
terms of delignification and chemical consumption. Discussion of the laboratory
and pilot plant studies and commercial application is provided.
75. Oxygen Bleaching Shows Potential
for Reducing Costs and Effluent
Problems
Chang. H.-M.
Pulp & Paper, March 1980. pp.
87-91.
Discussion of the oxygen bleaching process, advantages and disadvantages, new
processes being implemented, dissolved oxygen displacement delignification
process (DODEL), and low- and medium-consistency oxygen bleaching.
76. Oxygen Bleaching Shows Potential
For Reducing Costs. Effluent
Problems
Almberg, L.; Jamieson, A.;
Waldestam. S.
Pulp & Paper, March 1980, pp.
92-95.
Capital and operating costs, energy consumption, and degree of pollutant reduction
are compared for oxygen bleaching and biological treatment.
77. Chlorinated Organic Compounds Li
Effluent Treatment At Kraft Mills
Gergov, M.; Priha. M.; Talka. E.;
Valttila. O.; Kangas. A.
TAPPI Proceedings. 1988
Environmental Conference,
Charleston SC, April 1988. pp.
443-455.
The formation of chlorinated organic compounds and their behavior in effluent
treatment were studied for softwood and hardwood pulping at two kraft mills, one
modern with five-stage bleaching and an activated sludge plant, the other a
conventional mill with six-stage bleaching and an aerated lagoon. Total
organically bound chlorine, chlorophenolics, volatile chlorine compounds and
chloroacetones were determined in bleach plant effluents and at different stages of
effluent treatment.
78. Handbook for Pulp & Paper
Technologists
Smook. G.A.; Kocuttk. M.J.
Canadian Pulp & Paper Association
and TAPPI. 1989 Edition.
See Title.
11
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
79. Mill Experience With Oxygen And
Hydrogen Peroxide Bleaching
Sugei
Helmling, O.; Sueis. H.U.; Meier. J.;
Berger, M.
TAPPI Journal, July 1989. pp.
55-61.
Discussion of using hydrogen peroxide in both delignification and extraction
stages of bleaching and of reinforcing stages with oxygen and hydrogen peroxide.
Reinforcing the EO stage with hydrogen peroxide (EOF) is economical and gives
belter pulp qualities. EOP can be used efficiently as a first bleaching stage in sulfile
pulp mills.
80. Design, Startup and Operating
Experience for an Expanded ASB
Treatment System at Champion's
Pensacola Mill
Hilkke. J.; Koelsch. S.; Arceneaux.
D.
TAPPI Journal. September 1989.
pp. 111-117.
In December 1986, Champion completed the conversion of its Pensacola kraft mill
to 100% bleached pulp and paper operation. New pine and hardwood bleach lines
were set up, along with an oxygen delignification sequence. To successfully
operate the convened mill in compliance with new permit conditions, the project
included major modifications to the waste treatment system
81. Formation of Chlorinated Dioxins
and Fursns from Lignin and LJgnin
Model Compounds
Hue. R.G.
Dioxin '89, September 1989
82. Split Addition of Chlorine and pH
Control for Reducing Formation of
Dioxins
Hue. R.G.
TAPPI Journal, December 1989. pp.
121-126.
Process modifications in the chlorination stage produce high brightness, high
viscosity pulps with dramatically reduced levels of 2378-TCDD and 2378-TCDF,
and can be implemented faster and more economically than other techniques.
83. Effects Of Oxygen Extraction On
Organic Chlorine Contents In
Bleach Plant Effluents
Hong. Q.; Shin, N.H.; Chang. H.-M.
TAPPI Journal, June 1989. pp
157-162.
An unbleached krafl pulp and an oxygen-prebleached kraft pulp were chlorinated at
various chlorine dosages. The chlorinated pulps were extracted under conditions
for alkaline extraction (E) and oxygen-alkali extraction (EO). The organic chlorine
(OC1) in the pulps and in the spent liquors from each stage were determined, to study
the effect of EO on OC1 emission. EO alone had little effect on the OCI emission,
but EO combined with oxygen prebleaching was more effective in reducing the OCI
in both the spent liquor and in the pulp than a conventional extraction stage (E).
Chlorination of oxygen-prebleached pulp involves more oxidation and less
substitution than chlorination of nonoxygen-delignified pulps. The EO stage is
more efficient in converting the OCI to chloride. An EO stage can further reduce the
OQ discharge by lowering the requirement for chlorine.
84. Pilot Plant Trials For LRP, A New Hynninen, P.
Process For Precipitating Organic
Material
TAPPI Journal. February 1989. pp.
167-170.
The lignin removal process (LRP) is a new method for precipitating dissolved or
colloidal organic material of high molecular mass from fibrous waste sludge.
Effluents successfully treated have been taken from bleaching plants, barking
rooms and fiberboard mills from white water systems of some paper and fiberboard
mills and from CTMP mills. Pilot plant trials at a kraft pulp mill and at a fiberboard
mill produced results similar to those obtained by chemical precipitation and by
the previous laboratory tests. The pilot plant results support ideas for the design of
LRP effluent treatment plants. LRP is simple and inexpensive to incorporate into
existing mechanical and biological treatment and the method is ready for industrial
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TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
85. Reduction of Qiloro-organic
Discharge in the Nordic Pulp
Induitry
Jaakko Poyry
The report examines available technical measurei and their economic consequences
aimed at the reduction of the discharge of chlorinated organic materials from the
Nordic pulp industry.
86. AOX Testing Of Bleach Plant
Effluent*
Johannes, D.L.
Although there are no limits on AOX (adsorbable organic halogen) on current
bleach plant effluents in North America, recent government actions and public
opinion concerning chlorinated bleach effluents may require mills to monitor
their effluents on a regular basis for AOX and other components. A description of
the AOX determination and associated good laboratory procedures will be given. A
summary of some lab work on reducing AOX will be included.
87. Modified Continuous Kraft
Pulping-Now A Reality
Johansson, B.; Mjoberg, J.;
Sandstrom, P.; Teder, A.
Svensk Papperstidning, 10,
20(1984).
Full scale mill trials have been carried out in Varkaus, Finland with modified
continuous draft cooking in cooperation between Ahlstrom, Kamyr and STFI. The
process is characterized by a low initial concentration of alkali and by low
concentrations of lignin and sodium ions towards the end of the cook. The process
gives several advantages compared to the conventional one such as improved pulp
strength, better bleachability, lower variable costs and decreased environmental
load.
88. Ultrafiltration Of Bleach Plant
Effluent
Jonsson, A.-S.
Nordic Pulp and Paper Research
Journal. 1-1987, 23-29.
An up-to-date evaluation of capacity and retention of new membranes with regard to
bleach plant effluents has been made. The results from a trial of seven reverse
osmosis, ultrafUlration and microfiltration membranes are reported. The trial has
even included membranes not yet commercially available. The trial has
demonstrated that some of the tested membranes could probably combine a
satisfactory flux and an acceptable retention. A rough estimate of the costs shows
that treatment of the E-sUge effluent with ultrafiltration could be performed within
• total cost of approximately 25 SEK per tonne of pulp.
89. Experience With Extended
Delignification Of Hardwood And
Softwood Kraft Pulp In A
Continuous Digester
Kortelainen, V.A.; Backlund, EA.
TAPPI Journal, November 1985, pp.
70-74.
A multistage continuous kraft pulping process that provides a more selective
delignification than conventional kraft cooking is in commercial operation at a
mill in Finland. This improved selectivity is used to lower the pulp's kappa
number, which has contributed to reductions in the consumption of bleaching
chemicals, to reductions in the effluent load of the bleach plant, and to an increase
in the bleach plant's production capacity. When compared at the same kappa
number, the modified pulp has a higher viscosity, better strength and consumes
less bleaching chemicals than a conventional kraft pulp. Operating experiences,
consumption data and pulp-quality data for hardwood and softwood kraft pulps are
reported.
90. Bleaching And The Environment
Kringstad, K.P.; de Sous*, P.;
Johansson, L.; Kolar, M.-C;
Swanson, S.E.
Addendum to paper presented at the
TAPPI/CPPA 1988 International
Pulp Bleaching Conference,
Orlando, Florida. June 1988.
Paper discusses the formation of dioxins in the kraft bleaching process and
measures to decrease or eliminated such formation.
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TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
91. Influence Of Chlorine Ratio And
Oxygen Bleaching On The
Formation Of PCDFt And PCDDi In
Pulp Bleaching, The. Part 2: A Full
Mill Study
KringsUd, K.P.; Johansson, L.;
KoUr, M.-C; de Sousa. F.; Swanson.
S.B.; Glas, B.; Rappe, C.
TAPPI Journal, June 1989.
pp. 163-170.
We studied the effect of low-chlorine bleaching on the formation of
polychlorinaled dibenzofurans and polychlorinated dibenzo-p-dioxins (PCDFs
and PCDDs) in full mill-scale experiment!. An oxygen-bleached softwood kraft
pulp with a kappa number of 19.S was bleached using 33.3 kg of C12 and 6.2 kg of
C1O2 per ton of pulp in the first stage. A similar pulp was bleached using a mixture
of 19.3 kg C12 and 12.S C1O2 per ton to pulp. The amounts of PCDF and PCDD
dropped strongly in bleaching at the low chlorine ratio, the concentration of
PCDFs and PCDDs in general was only slightly above the detection limits in the
pulp as well as in the total effluent. These results confirm those of the laboratory
study (Pan 1) which suggested that the chlorine ratio used in the first bleaching
stage is important in the formation of PCDFs and PCDDs.
92. Spent Liquors From Pulp Bleaching Kringstad. K.P.; Ltndstrom. K.
Environmental Science A.
Technology. li(8). 236A( 1984).
Impact of chlorinalion and extraction stage variables on formation of chlorinated
organics.
93. Bleaching And The Environment
Kringstad. K.P.; McKague. A.B.
TAPPI/CPPA Proceedings. 1988
International Pulp Bleaching
Conference, Orlando, Florida, June
1988.
Combinations of treatment of effluents in aerated lagoon, the use of oxygen
bleaching, the partial replacement of chlorine by chlorine dioxide and/or applying
low chlorine ratio bleaching in combination with reinforced alkaline extraction
may yield effluents: which meet advanced requirements regarding protection of fish
and other organisms living in pulp mill receiving waters against toxic effects and
according to all present knowledge reduce chances of any widely spread detrimental
environmental effects of chlorinated organic materials.
94. Studies on the Mechanism of
PCDD/PCDF Formation during the
Bleaching of Pulp
LaFleur. L.E.; el al.
Dioxin '89. September 1989
95. Oxygen Bleaching, Today's
Standard For Pollution Abatement
PRENOX Next To Come?
Lindblad. P.; Norden. S.
The Fifth Technical Seminar at
Sunds Defibralor Proceedings,
Sundsvall, June 1988.
Paper discusses modified cooking, oxygen delignificauon and PRENOX.
Information is presented related to kappa numbers, AOX, TOC1 and costs.
96. Nitrogen Dioxide Preoxidation Lindqvist, B.; Marklund, A.;
Oxygen Delignification - A Process Ljndiirom. L.-A.; Norden, S.
For The Future?
TAPPI Proceedings, 1985
International Pulp Bleaching
Conference, pp. 221-225.
In order to produce a low kappa number pulp after an oxygen stage nitrogen dioxide
preoxidation was superior to modification of the kraft cook, kappa number 9-10
should be compared to 13-14 in the latter case. A number of these methods made it
possible to further reduce the kappa number to about 8 after the oxygen stage.
Kappa number reduction from 17 to 9, the first figure representing a conventionally
cooked and oxygen bleached kraft pulp, decreased the consumption of active
chlorine up to 55%. COD, BOD7 and total organic chlorine were reduced with 55%,
while color was reduced with 75%.
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
97. Selective Removal Of Chlorinated
Organics From Kraft Mill Tout
Effluents In Aenled Lagoons
Lindilrom, K.; Mohamed, M.
Nordic Pulp and Paper Research
Journal No. 1/1988. pp. 26-33.
The efficiency of aerated lagoon in reducing the quantity of various chlorinated
organics occurring in krafl pulp mill total effluent was assessed. The most abundant
chlorinated neutrals, phenols and acids so far identified, as well as the non-volatile
organochlorine in the influent and effluent to the lagoon were measured by methods
earlier established. The most efficient removal was observed for the most abundant
chlorinated compounds occurring in the waste water (chlorinated acetic acids and
chloroform). Among the chlorinated organics studies, DOS (1,1-dichlorodimelhyl
sulfone) was apparently the least affected by aerated lagoon treatment. Extended
retention period in lagoons from 2.5 to S days had almost quantitatively removed
the acids, particularly trichloroacetic acid.
98. Oxygen Delignification Systems:
Synthesizing the Optimum Design
Myers, M.; Edwards, L.; Haynes, J.
TAPPI Journal, April 1989, pp.
131-135.
The authors used computer simulation to synthesize Ihe best configuration of
washing equipment and determine the optimum dilution factor for a typical oxygen
delignification system.
99. Chlorinated Organic Matter In
Bleached Chemical Pulp Production
PanU: Measurement Techniques
For Effluents
Odendahl, S.M.; Weishar, K.M.;
Reeve, D.W.
Presented at the CPPA Technical
Section Annual Meeting, January
31-February 3, 1989.
Quantification of the chlorinated organic matter discharged from chemical pulp
bleach plants is becoming an important part of harmonizing operations with Ihe
environment. AOX (adsorbable organic halogen) measurement involves
adsorption of all organic matter onto activated carbon, mineralization by
combustion forming HC1, and then determination of chloride. The principles and
details of AOX techniques and AOX instruments are described.
100. Survey of Chlorine Dioxide
Generation in the United States, A
Owen, D.; Perot, P.; Harrington, E.;
Scribner. H.C.
TAPPI Journal, November 1989. pp.
87-92.
There is plenty of room for improvement in the processes used to produce chlorine
dioxide. With its impact on the environment and bleaching costs, mills will spend
more time reviewing the operations of their chlorine dioxide generation plants.
101. Direct Biological Bleaching of
Hardwood Kraft Pulp with Ihe Fungus
Corioius Versicolor
Pake, M.C.; Jurasek. L.; Ho. R.;
Bourbonnais, R.; Archibald, F.
TAPPI Journal, May 1989. pp.
217-221.
Researchers at PAPRICAN screened various microorganisms and found that
Corioius versicolor can bleach hardwood krafl pulp by up to IS percentage points
with a drop in kappa number from 11.6 to 7.9. The bleaching effect of C. versicolor
appears to be limited to hardwoods since experiments with spruce pulp failed to
increase brightness.
102. Dechlorination Of
High-molecular-weight
Chlorolignin By The White-rot
Fungus P. Chrysosporium
Pellinen. J.; Joyce, T.W.; Chang,
H.-M.
TAPPI Journal. September 1988.
pp. 191-194.
Dechlorination of chlorolignin in pulp bleaching wastewater was studied using the
white-rot fungus P. chrysosporium immobilized on a rotating biological
contactor. The total organic chlorine content of chlorolignin decreased almost by
50% during one day of treatment. The corresponding amount of inorganic chloride
was liberated into the solution. Correlation studies suggested that dechlorination,
decolorization, and degradation of chlorolignin (as COD decrease) are
metabolically connected, although these processes have different rales. Size
exclusion chromatography showed that polymerization took place in Ihe early
stage of the treatment. Low-molecular weight degradation products were not
observed.
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
103. Subitituting Chlorine Dioxide for Pryke, D.C.
Chlorine
TAPPI Journal, October 1989. pp.
147-155.
Increasing chlorine dioxide substitution minimizes bleaching chemical
consumption, decreases costs, and improves effluent quality.
104. Chlorinalion-stage Mixing
Practices
Pryke. D.C.
TAPPI Journal. June 1989, pp.
143-149.
Examples of mill chlorinaiion stages show that many process and equipment
choices are available to meet the environmental, economic, and process demands of
the modem bleach plant.
105. Chlorinated Organic Matter In Reeve, D.W.; Earl, P.P.
Bleached Chemical Pulp Production:
Pan I - Environmental Impact And
Regulation Of Effluent*
Pulp A Paper Canada. 90(4):
65(1989).
In two recent Swedish studies, bleach plant effluents have been found to have
significant environmental impact even after extreme dilution. These findings are
contrary to earlier Swedish work and to North American experience but have
nonetheless led to regulations in Sweden requiring decreasing discharge to as low as
1.5 kg TOCI (total organic chlorine) per tonne of pulp, 25% of the amount
discharged from conventional bleaching of softwood kraft pulp.
106. Modified Kraft Cooking - Ways Of
Application
Sandstrom, P.E.; Panning, A.M.;
Soderqvisl Lindbhtd, M.; Teder. A.
TAPPI Seminar Proceedings,
Bleaching and the Environment,
Seattle, Washington. September
1988. pp. 279-286.
Modified kraft cooking is based on principles that originate from the kinetics of
delignification and carbohydrate degradation. Some of the principles contradict
others, so it is therefore necessary to optimize process conditions to gain a net
improvement in pulping selectivity. This paper presents how different ways of
applying the principles can be evaluated using a mathematical model of continuous
kraft pulping. Mill trials and laboratory investigations show that correctly
applied, the principles result in a process that both reduces bleach plant effluent
and operating costs while maintaining the pulp quality. The modified kraft
cooking process can probably be even further improved based on advancing
knowledge in the field of pulping chemistry.
107. Formation Of Chlorinated Lignin Sarkanen, K.V.
Products
TAPPI Seminar Proceedings,
Bleaching and the Environment,
Seattle. Washington, September
1988. pp. 313-327.
Paper discusses the 1) chemistry of formation of chlorinated lignin products such as
chlorolignin, chlorinated guaiacols, calechols, phenols, vanillins, chlorinated
aliphatics, chloroform and methanol and 2) the potential formation of PCDDs and
PCDFs from lignin.
108. Effects of Brownitock Washing on
the Formation of Chlorinated
Dioxins and Furans During
Bleaching, The
Hise. R.G.; Hintz, H.L.
TAPPI Journal. January 1990. pp.
185-190.
Poor brownstock washing led to increased levels of PCDDs and PCDFs in softwood
pulps after chlorinaiion stage and in the final effluent. Additional washing in the
laboratory with copious amounts of aqueous ethanol decreased chlorinated dioxins
and furans by 80%. These results demonstrate the presence of solvent-extractable
precursors for PCDD/Fs associated with this unbleached pulp. Also found that
spiking unbleached pulp with higher than normal levels of defoamers used had no
significant effect on the formation of PCDD/Fs after bleaching.
109. The Impact Of Environmental Silander, R.
Concern On The Future Of Chemical
Pulping And Bleaching
International Seminar at Sunds
Defibrator AB, 1988.
Paper discusses evolution of environmental regulations and their impact on
production processes for the 1990's.
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TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
110. Two Cue Studies On The Cold Blow Sjodin, L.; Peuenton, B.
Technique For Batch Kraft Pulping
TAPPI Journal, February 1987. pp.
72-76.
The ASSI Karlsborg mill is the first to practice extended delignificalion and cold
blow process techniques in its batch digester plant, and the NCB Dynes mill started
up a completely new batch cold blow digester plant recently.
Ill- Operational Experiences From A Soderberg, J.; Almberg, M.;
New Chlorination Control System Kubulnieks. E.; Lundqvisl. S.-O.;
Based On On-line Measurements Of Lowenberg, C.
Kappa Number
TAPPI Journal, November 1988. pp.
145-149.
In a new control system for chlorination, the change of active chlorine is based on
on-line measurement of the kappa number of Ihe pulp entering the bleach plant.
The control system also accounts for variations in production, temperature, etc.
The kappa number after the alkali extraction stage is also measured on-line. The
control system is installed in a bleach plant for softwood kraft pulp, where the
residual chlorine has been reduced by 3 kg Cl/ton of pulp, the quantity of
downgraded pulp has decreased, and the working conditions have improved. The
control system is flexible during operation under various bleaching conditions.
112. Personal communication between
D. G. Bodien of EPA and V.E.
Lemon, Jr. of IngersoU-Rand
Company
IngersoU-Rand Company
Communication contains information related to costs related to compaction baffle
filters and oxygen delignificalion systems.
113. Determination of Total Organic
Chlorine in Pulp
Stevens, B.; Sell, L.O.; Eaity, D.B.
TAPPI Journal. July 1989. pp.
181-182.
Analytical method for TOO in pulp described.
114. Rapid Displacement Heating in
Batch Digesters
Swift, L.K.; Dayton, J.S.
Pulp & Paper Canada, 89:8, pp.
T264-T270.
Rapid Displacement Healing (RDH) has now reached full commercial operation in
two mills. In addition to dramatic digester area steam savings these mills have
experienced reduced soda loss off brown stock washers; reduced evaporator load;
lower strong black liquor viscosities; increased digester production and improved
pulp quality.
115. Advances in Bleach Plant Design Tail, D.H.
Lower Capital and Operating Costs
Pulp &. Paper. January 1986, pp.
70-72.
Improved washing and mixing technologies reduce chemical consumption without
offsetting power usage and effluent increases.
116. Personal communications between Statens Naturvlrdsverk
D. G. Bodien of EPA and A. Melin of
Suuens Naturvlrdsverk
Communications contains information related to oxygen delignification,
extended delignification, biological treatment at Swedish kraft pulp mills. Also
contains removal efficiencies for ultrafillrauon facility at MoDoCell Husum mill.
117. Membrane Filtration As A
Technique For Effluent Control In
Pulp And Papeimaking
ThoneU, L.; Orchard, T.
TAPPI Seminar Proceedings.
Bleaching and the Environment,
Seattle, Washington, September
1988. pp. 227-243.
Paper presents information related to membrane filtration (ultrafiltration and
reverse osmosis). Applications, installations and costs are presented.
118. Bleaching of Kraft Pulp Without Vaheri, M.; et al.
Formation of Dioxins
Dioxin '89. September 1989
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TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
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REFERENCE
SYNOPSIS
119. Some New Insights Into Hie
Origin* Of Dioum Formed During
Chemical Pulp Bleaching
Voii. R.H.; Luthe, C.E.; Fleming,
B.I.; Berry, R.M.; Allen. L.H.
Paper presented at the 1988 CPPA
Environment Conference,
Vancouver. B.C.. October 25-26,
1988.
Oil-based pulp mill additives, particularly brownslock defoamers. have been
identified as potential sources of unchlorinaled furan (DBF) and dioxin (DBD)
which can be convened to their chlorinated forms in the chlorination stage of pulp
bleaching. To get a clean indication of the effect of defoamers on the formation of
chlorinated dioxins and furans (together commonly referred to as dioxins), a higher
than normal defoamer charge (1% by weight on o.d. pulp) was used for these
preliminary experiments. Subsequent studies in our laboratory have established
that DBF-contaminated defoamers even when applied at normal industrial charges
(i.e., 0.1 to 0.3%) were able to cause significant increases in the dioxin content of
the final chlorinated pulp.
120. Dioxin/Furan In-Mill Source Studies Weinbauer, I.; Gilbert, F.A.
at Consolidated Papers, Inc.'s Kraft
Division
TAPPI Proceedings. 1989
Environmental Conference. April
1989. pp. 359-372.
Impact of oxygen delignification on hardwood bleach line reviewed.
121. Industry's Effluent Problems Spawn Galloway, L.R.; Hebninen, P.I.;
New Engineering Technology. Carter, D.N.
Design
Pulp &. Paper, September 1989. pp.
91-97.
Article reviews development of environmental regulations for Sweden, Canada and
U.S.. Also reviewed are inplant and external technologies installed to reduce the
discharge of chlorinated organics. These include extended delignification, oxygen
delignification, advanced pulp washing, C1O2 substitution, reduced water usage and
biological wastewater treatment.
122. STFI OPTI-Kappa Analyzer.
Application and Accuracy
Kubulnieks, E.; Lundqvist. S.-O.;
Paltersson, T.
TAPPI Journal, November 1987, pp.
38-42.
STFI has developed an on-line kappa number measurement system based on
absorption of ultraviolet light. This measurement system is now a
well-established systems which has been in operation in different applications for
more than three years in Swedish mills. The operating experiences are good, with
low maintenance and, in most cases, almost 100% availability.
123. Kraft Mill Effluents in Ontario
Bonsor, N.; McCubbin, N.; Sprague,
J.B.
Technical Advisor Committee, Pulp
&. Paper Sector of MISA, Ontario
Ministry of the Environment,
Toronto, Ontario, Canada, April
1988.
This report reviews the effluent discharged by the kraft pulp industry in Ontario.
and recommends a water pollution control strategy. The recommendations are
based on the needs of the aquatic ecosystem, current technology, water pollution
control practices in other kraft pulp producing jurisdictions, and economic factors.
124. Alternate Process for Bleaching
Could Help in Reducing TOds.
Dioxin
Galluch, R.J.
Pulp & Paper, September 1989, pp.
145-147.
Monox-L technology, successful in five plant trials, maintains pulp quality similar
to that produced with chlorine dioxide.
125. New Flocculation Process Portends
Progress in Color, Dioxin Removal
Mass. R.P.; Neal. J.P.
Pulp & Paper, September 1989, pp.
154-158.
Article discusses how Hansel process removed 90 to 95 percent of lignin. tannins,
and dioxin from secondary treated bleached kraft mill wastewater.
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TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
126. USEP A/Paper Industry Cooperative
Dioxin Study: The 104 Mill Study
(Preliminary Results)
Whiuemore. R.C.; UFlcur, L.R;
Gillespie. W.J.; AmendoU. G.A.;
Helms, J.
Dioxin '89 Proceedings, Toronto,
Ontario. September 1989.
This paper summarizes the distribution of concentrations of 2378 substituted
dibenzo-p-dioxins and dibenzofurans in bleached kraft and sulfile mill pulps,
waslewater sludges, and treated effluents in the U.S. in mid-1988.
127. Dechkmnalion and Decolonization
of High-Molecular-Weight
Chlorolignin from Bleach Plant
Effluents by an Oxidation Process
Sun, Y.-B.; Joyce, W.; Chang, H.-M.
TAPPI Journal. September 1989.
pp. 209-213.
The total organic chlorine and color of the high-molecular-weight chlorolignin
from spent alkali extraction-stage effluent were effectively removed by an oxygen
oxidation process. Under the best conditions, about 70-80% of the TOO and
60-70% of the color were removed in less than one hour. A process combining
ultrafiltration. oxidation, and biological treatment could be an effective.
economical option to remove TOC1 and color from spent alkali extraction effluent.
128. Treating Bleaching Effluent for
Suspended Solid* and Color
Garcia-Heras, J.L.; Fbrster, C.F.
TAPPI Journal. September 1989,
pp. 199-206.
The paper discusses a study of the main characteristics of a coagulation system lo
remove chromophoric compounds from a bleach plant wastewater by iron and
calcium cations. The treatment was successful, with a color removal of 99% with an
iron dose of 6-7 molei/m3. the residual suspended solids were low (about 10 mg/1),
but the residual turbidity (5-10 NTU) was higher than the initial value, and the
sludge volume was high (over 20%).
129. Chlorinated Organic Matter in
Bleached Chemical Pulp Production
PartrV: The Occurrence of
Chlorinated Organic Matter in
Bleached Pulp
Reeve. D.W.; Weishar. K.M.
Presented at the CPPA Technical
Section Western Conference,
Whistler. B.C.. May 25-27. 1989.
Some of the chlorine covalently bonded to pulp during chlorination is not removed
by hydrolysis or dissolution but remains in the pulp. Total organically-bound
chlorine in fully bleached hardwood pulp was found to be in the range 200 to 2200
ug Cl/g oven dry pulp while Cl in fully bleached softwood pulp was not as variable,
with the average being approximately 400 ug/g o.d. pulp. Water-extracted AOX
was less than 6% of the total.
130. Monox-L for Decreasing AOX Hurst, M.M.
and/or Dioxin
CPPA Proceedings, 76th Annual
Meeting Technical Section,
Montreal, Quebec, February 1-2,
1990, pp. B313-B314.
Monox-L is a cost effective bleaching agent which can significantly reduce the
levels of both AOX and dioxins produced as compared lo conventional bleaching
sequences.
131. Pulping Processes
Rydholm. S.A.
Interscience, New York, 196S.
132. Non-chlorine Bleaching of
MCC Pulp
Dillner, B.; Larsson, L.-O.; Tibbling.
P.
TAPPI Proceedings, 1989 Pulping
Conference. Seattle, Washington.
The paper discusses how a combination of modified continuous cooking (MCC)
and oxygen delignification gives a pulp of sufficiently low kappa number (13) for
final bleaching without the use of elementary chlorine. MCC oxygen pulp has been
bleached D(EO)DD and D(EOP)DD to 90%+ ISO brightness with retained strength
characteristics. The effluent load from the D(EOP)DD sequence is expected to be
very low, the measured AOX being only 0.9-1.0 kg/A DMT.
19
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
133. Impact of High Chlorine Dioxide
Substitution for Chlorine on the
Oxygen Deligrafied Pulp at
Espanola
Munro. F.C.; Chandrasekaran, S.;
Cook. C.R.. Piyke, D.C.
TAPP1 Proceedings 1989 Pulping
Conference, Seattle, Waihinglon.
E. B. Eddy at Espanola embarked on a mill trial to increase the C1O2 substitution
from 10% to 50% in an effon to eliminate polychlorinaled dioxini and furani in the
bleached pulp and effluent. OC/DEoHD was the bleaching sequence used. The
results indicate that at 50% substitution the polychlorinaled dioxini are
non-detectable in both pulp and effluent and chlorinated organic compounds
measured as AOX have decreased significantly in the Meachery effluent.
134. Personal communication between Westvaco Corporation
D.G. Bodien of EPA and O.B Bums,
Jr. of Westvaco Corporation
Communication contains information related to status of process changes (split
chlorine addition/pH adjustment) made at the three Weslvaco bleached kraft pulp
mill, capital cost associated with these changes, and implementation time to
design and construction of these changes.
135. Monox-L Information and Data
Quantum Technologies, Inc.
Information and data related to the use of Monox-L as a bleaching chemical.
Including BOD. COD, Color. TOCI, AOX, chloroform and dioxin effluent data.
capital and O &. M costs and energy requirements.
136. Personal communication between James River Corporation
D.G. Bodien of EPA and C. Whiuker
of James River Corporation
Communication contains analysis for Dibenzofurans in defoamers used at the
James River Camas, Washington mill.
137. Personal communication between
D.G. Bodien of EPA and C
Luhrmann and J J. Miele of Kamyr,
Inc.
Kamyr, Incorporated
Communication contains information related to the costs and implementation
time for installation of MCC digestion systems.
138. USEPA/Paper Industry Cooperative USEPA, Office of Water Regulations
Dioxin Screening Study and Standards
EPA-440/1 -88-025, March 1988
139. Modified Continuous Cooking
Dillner, B.
Paper presented at Kamyr, Inc. Low
Chlorine Bleaching Seminar,
Atlanta. 1987-12-08.
Modified continuous cooking implies a con/counter-curren! process where the
alkali concentration is lower than normal at the beginning of the cook and is then
raised at the end. MCC pulp has a higher than normal viscosity, lower kappa
number, equal or better strength and results in a reduction of the effluent load by 25
to 30%.
140. Oxygen Delignification
Backlund. A.
Paper presented at Kamyr, Inc. Low
Chlorine Bleaching Seminar,
AU»nu. 1987-12-08.
Paper presents information relative to oxygen delignification. Installations,
costs, environmental effects and discussion of high and medium consistency
systems are presented.
20
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
141. On the Formation of PCDDs and
PCDFi in the Bleaching of Pulp
Rappe. C; Swanson, S.; Glas. B.;
Kringslad, K.P.; de Souia. P.;
Johansson, L.; Abe, Z.
Pulp & Paper Canada. 90:8, 1989.
pp. 42-47.
This investigation was done to obtain a better understanding of the factors
influencing the formation of PCDDs and PCDFi in pulp bleaching. The results
indicate that unchlorinated dibenzofuran may be a precursor for PCDFs. The role of
unchlorinaled dibenzo-p-dioxin as precursor is more doubtful. Condensales may
promote the formation of PCDDs and PCDFs. The reason for this is at present
unclear.
142. Organo-chlorine Discharges in Hall, B.R.; Fraser, J.; Garden, S.;
Wastewaters from Kraft Mill Bleach Comacchio, L.-A.
Plants
Pulp & Paper Canada, 90:1. 1989.
pp. 68-72.
Samples were collected from process streams in four kraft bleach plants with
different bleaching sequences. Chemical analytical data were compiled to compare
the potential suitability of anaerobic treatment technology for dechlorination of
the sewered streams. Organo-chlorine concentrations and discharge rates are
summarized for each bleaching sequence and for parallel plants bleaching hardwood
and softwood pulps, preceded by oxygen delignificalion.
143. Mil] Trials of Substantial Pryke, D.C.
Substitution of Chlorine Dioxide for
Chlorine: Part U
Pulp & Paper Canada. 90:6. 1989.
pp. 93-97.
Recent trials in market softwood kraft pulp mills situated on the B.C. coast and in
the southern U.S. have shown that increasing chlorine dioxide substitution from
10 to 30 percent in the chlorination stage decreases bleaching chemical
consumption and bleaching cost while maintaining pulp quality. Bleaching
chemical savings of C$1.SO to 2.SO per tonne were achieved.
144. Swedish, Finnish Mills and
Suppliers Show U of T Students
What's New
Earl. P.F.; Odendahl. S.; Martinez,
M.; Tomar, P.; Bratu, C.
Pulp & Paper Canada. 90:9. 1989.
pp. 17-20.
Paper presented is a trip report for tour of pulp and paper mills, research centers and
universities in Sweden and Finland.
145. Pulp and Paper Technology, Second Britt. K.W.
Edition
Van Nottrand Reinhold Company,
New York, 1970.
Text
146. New Pressurized Compaction Filter Tail, D.
Lowers Operating and Capital Costs
147. Ultnfiltration for Removing Color Lundahl, H.; Mansson, I.
from Bleach Plant Effluent
Pulp & Paper. November 1985, pp.
TAPPI Journal, April 1980, p. 97.
Pulp washer with compaction baffle and pressurization permits low-level
installation, lower power consumption, and greater efficiency.
Paper discusses ultrafiltration for the removal of color from bleach plant effluents.
148. dosed Cycle Technology Report Jain, A.K.
NCASI Report, September 1988.
This report is an assessment of the current stale of knowledge of various closed
cycle technologies. Technologies included are Rapson-Reeve process,
Billerud-Uddehokn and other resin processes, activated carbon adsorption,
chemical coagulation, ullrafiltration and reverse osmosis. The report also includes
information on the problem encountered with implementing these technologies,
and recommends the areas of research that could be pursued under the R & D
program.
21
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
149. Modifying the Bleaching Process 10
Decrease AOX Formation
Licbergou. N.; van LJerop, B.;
Notin. A.; Faubert, M.; Laflamme. J.
CPPA Proceedings. 76ch Annual
Meeting Technical Section,
Montreal, Quebec, February 1-2,
1990, pp. B229-B238.
This report describes the effects of Eo, Eop and O delignificalion and of a wide
range of chlorine dioxide substitution levels in the chlorination stage on the
properties of pulp and bleach effluent. Increasing the chlorine dioxide substitution
to 70 % produced less chlorinated phenolic compounds in the bleach effluent*.
The BOD and COD in the effluent decreased only with very high chlorine dioxide
substitution levels.
ISO. Mill Trials of Substantial
Substitution of Chlorine Dioxide for
Chlorine
Pryke, D.C.; Francis, R.C.; Reeve,
D.W.
TAPPI Proceedings, 198S Pulping
Conference, pp. S43-5S1.
Three mill trials have recently been conducted in Canada where C1O2 substitution
was raised to the 30-50% range. Total equivalent chlorine and caustic consumption
decreased significantly in all three mills resulting in savings of $1.55, $1.94 and
$2.36 CDN/ADT. Pulp quality parameters were unchanged: strength, cleanliness
and brightness. Bleach plant effluent colour and BODS were significantly
decreased: Toxicily lest results were somewhat erratic but decreased toxitity was
indicated.
151. Personal communications between
D.G. BodienofEPAand A.
Axelsson of ABB Automation
ABB Automation
Communications contains information related to the STFI OPTI-Kappa analyzer
including capital cost, delivery time and installations list.
152. RDH Pulping - Better Pulp
Properties Through Improved
Selectivity
Swift. UK.
Unpublished, available from author
or Beloit Corporation.
The steam savings capability of the new RDH cooking technology has been well
documented. New studies are surfacing which are beginning to explain why RDH
cooking produces pulp of significantly higher strength characteristics than other
processes and further more, why RDH cooking can be extended to extraordinarily
low Kappa levels.
153. Personal communications between
D. G. Bodien of EPA and messieurs
J. Morrison, P. Sullivan and B.
Fagerlund of Beloit Corporation
Beloit Corporation
Information in communications relate to costs and implementation times
associated with RDH pulping systems.
1S4. Peroxide Delignificalion of
Unbleached Chemical Pulp by
Minox Process
Caries, I.E.; Lemoyne, H.; Logan.
W.R.
TAPPI Proceedings. 1980 Pulping
Conference, Atlanta, GA, pp.
325-332.
Unbleached chemical pulp can be delignifted by hydrogen peroxide in an alkaline
medium. Laboratory results obtained on bisulfite and kreft pulps are described.
Using this process on kraft pulp a reduction by 45% of the bleach plant effluent
color has been achieved, together with savings in overall bleaching operation
costs.
155. Personal communication between
D. G. Bodien of EPA and T. Mullen of
Air Products A Chemicals, Inc.
Air Products & Chemicals, Inc.
Communication relates to pulp mills who have purchased, are presently installing
or have installed oxygen delignification systems.
22
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
156. Closed-Cycle Bleached Kimft Pulp
Mill - 1978. The
Reeve, D.W.; Rowlandson. G.;
Kramer. J.D.;Rapson, W.H.
TAPPI Journal, Auguit 1979.
pp.51-54.
Paper discusses the first IS months of operation of the world's first installation of
the closed-cycle bleached kraft pulp mill. The plant has performed well.
concentrating white liquor to recover salt which has been use for C1O2 production.
Most bleaching systems are readily incorporated in to the closed-cycle mill filtrate
recovery strategy. Black liquor evaporator condensate segregation, stripping and
reuse are important aspects of the closed-cycle mill and are described along with
chemical, water and energy considerations.
157. Personal communication between
D. G. Bodien of EPA and L.-A.
Lindstrom and P. Hickenger of
Sunds Defibrator
Sunds Defibntor
Communication deals with information related to installation of oxygen
delignification systems.
158. New Catalyst Improves Polysulfide Lightfoot, W.E.
Liquor Makeup, O2 Delignification
Pulp & Paper, January 1990, pp.
88-93.
Paper deals with polysulfide cooking and its impact on the recovery boiler. Use of
polysulfide liquor makeup enables mills with limited recovery boiler capacity to
employ oxygen delignification. Costs are provided which show that the ROI for
the process is on the order of 6-7 months.
159. Personal communication between
D.G. Bodien of EPA and W.E.
Ughtfoot of Chiyoda International
Corporation
Chiyoda International Corporation
Communication deals with polysulfide cooking, installation time for the process
and facilities where system is in operation.
160. Organochlorine Discharges from a
Bleached Kraft Pulp Mill with
Oxygen Delignification and
Secondary Treatment System
Cook, C.R.
CPPA Proceedings, 1988
Environmental Conference,
Vancouver, B.C., October
25-27,1988, p.37.
A seven month study of Organochlorine loadings from the E.B- Eddy kraft pulp mill
in Espanola was completed in July 1988. The study showed that the mill's
secondary treatment system discharges less than l.S kg A OX/AD tonne of pulp to
the receiving water. The majority of the AOX, BOD and TOC removal in the lagoon
occurred during the first 2.5 days of treatment in Cell 1 of the lagoon. Cell 1 also
removed all of the acute toxicity from this mill effluent in 2.5 days.
161. Effluent-Free Bleached Kraft Pulp
Mill - PartXm: The Second Fifteen
Yean of Development, The
Reeve. D.W.
Pulp A Paper
In the 15 years since conception and the 5 years since mill start-up, there has been
great progress in the technology of elimination of pulp mill effluents by recycling.
Bleach plant effluent use in the pulping chemical recovery cycle and ultimate
destruction in the recovery furnace has been demonstrated in mill operation.
Recovery of sodium chloride and ks use to regenerate bleaching chemicals has also
been practiced and proven. Development is continuing.
23
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
162. Mill Trial* of Substantial Rempel, W.; Pryke. D.C.; Ouchi.
Substitution of Chlorine Dioxide for M.D.
Chlorine - Part HI: Medium
Consistency
Unpublished
A recent trial at a market softwood kraft pulp mill on the west coast of British
Columbia with a medium consistency chlorination stage has shown that increasing
C1O2 substitution from 5 to 50% decreases bleaching chemical consumption,
bleaching cost and improves pulp quality. Discharges of chlorinated organic
compounds, including PCDDi and PCDFs, from the pulp mill to the receiving water
have been decreased by over 50%. PCDDs and PCDFs in bleached pulp have also
been decreased substantially.
163. USEPA/Paper Industry Cooperative USBPA. Office of Water Regulations
Dioxin Study and Standards
Unpublished
164. Personal communication between Mo och Domijo AB
D. G. Bodien of EPA and K. UUin of
Mo och Domsjo AB
Communication contains information related to the ultrafUtration of the caustic
extraction filtrate at the MoDo Husum mill.
165. NO2 Treatment of Kraft Pulp
Followed by Oxygen Bleaching -
Influence of Black Liquor
Samuelson, O.; Ojteg. U.
TAPPI Journal, February 1990. pp.
141-146.
Kraft pulp from softwood containing large amounts of black liquor was delignified
by oxygen bleaching following prelreatment with nitrogen dioxide. The alkaline
pulp was treated with NO2 for a few minutes at high or medium consistency. After
ripening for 180 minutes the pulp was oxygen bleached. A kappa number of 3.5
was obtained even when the pulp contained 43 kg of solids from the black liquor per
1000 kg pulp.
166. Technologies for Reducing Dioxin
in the Manufacture of Bleached
Wood Pulp - Background Paper
Office of Technology Assessment,
Washington, D. C.
Library of Congress, Catalog Card
No. 89-600719.
Discussion of alternative technologies to reduce formation of dioxin in bleached
pulp. Oxygen pretreatment for delignification and substituting other chemicals for
chlorine are evaluated.
167. Hydrogen Peroxide in Alkaline
Extraction Improves Pulp Quality
Hook. J.; Meuller. L; Wallin. S.
Nordisk Cellulosa 2. No. 2, March
1985, pp. 47-50.
Several bleach plants are using hydrogen peroxide in the alkaline extraction stage.
Advantages and disadvantages of this practice are discussed.
168. Dioxin
Alkaline Paper Advocate
Alkaline Paper Advocate 2, No. 2,
July 1989. pp. 17-18.
Summary of mechanisms and effects of dioxin formation in bleached kraft process
is presented. Discussion on European, Canadian and U. S. regulatory issues. List of
mills using/planning to use oxygen bleaching is given.
169. New Pollution Control Phase Means Karl. W.
More Than Just Dioxin Prevention
Pulp A Paper Journal (Canada),
41:9. October 1988. pp. 18-21.
Overview of industry's response to the problems of dioxin in bleaching processes.
General review of research in Canada, Sweden, Finland & U.S. on dioxin formation
and disposition.
170. PRENOX - Oxidation of Pulp with Brannland, R.; Simonson, O.
Nitrogen Dioxide and Oxygen Prior
to Oxygen Delignification Could
Reduce Pollution
Swedish Pulp A Paper Journal No. 2,
1986, pp. 48-50. 53-54.
Findings of pilot plant investigations in a mill in Sweden using PRENOX process
is discussed. PRENOX process reduced kappa no. in pulp. BOD, COD and TOQ are
reduced with decreasing kappa no. Increased washing and chlorine dioxide
substitution further reduced TOQ.
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
171. Reduce TOO with OxO Process Lacheiul. D.; Muquet, M.
CPPA Annual Meeting Preprints,
75B. Montreal, Que.. February 2-3.
1989. pp. 187-192.
Findings of OxO process investigations presented. OxO process consists of
oxygen delignification followed by low charge of chlorine followed by oxygen
extraction stage. OxO process can be optimized to reduce chlorine requirement.
Comparison with chlorine dioxide bleaching processes reported.
172. Reduced Discharge of TOC1 with a
Hot (EO) Stage
Sjoblom. K.; Hardmeier, P.
TAPPI Proceedings. 1988
International Pulp Bleaching
Conference, Orlando, FL, June 5-9,
1988, pp. 263-270.
Chlorine consumption can be reduced by increased temperature in the EO stage. For
a given pulp and bleaching sequence, a TOC1 level can be achieved for a minimum
total consumption of chlorine dioxide in the hot EO stage. If economics permit.
peroxide added to the EO stage at 75 C can substitute for an EO stage at 90 C.
173. How to Cope with TOO (Total
Organically Bound Chlorine)
Bnnnland, R,; Possum G.
TAPPI Proceedings, 1987 Pulping
Conference, Washington, D. C..
November 1-5. 1987. Book 2 pp.
243-248.
Review of regulatory control for TOO implemented in Swedish mills presented.
Effects of TOCI on bottom living organisms in receiving waters presented briefly.
Alternatives for reaching TOCI formation in pulp bleaching such as extended
delignification, PRENOX, oxygen delignification, chlorine dioxide substitution
presented.
174. Sulfite Mills Move to Cut TOCI Ducey, M.K.. Technical Editor
Pulp & Paper International, 29:12,
December 1987. pp. S4-SS.
Discussion of results in retrofitting sulfite mills in West Germany and Wisconsin
with first stage bleaching using oxygen, peroxide and NaOH. Reduction in
chlorine consumption and effluent TOCI achieved as well as reduced toxicity. Cost
justification is also discussed.
175. Dechlorinalion and Biological Botloer. J.; Palzold, J.; Krause, T.H.,
Treatment of Chlorinated Organic Schempp, W.
Substances
International Symposium on Wood
Pulping Chemicals Proceedings,
Paris, April 27-30, 1987, VoL 1. pp.
171-174.
Treatment of bleach plant effluent by dechlorination, UV and biological processes
reduced AOX by 60%. Post treatment using aerobic fixed-bed reactor reduced AOX by
over 90%.
175. Mill Experience of Oxygen
Delignification
Kiumra, M.
Japan TAPPI Journal, 42:1, January
1988. pp. 52-55.
Oxygen delignificalion in a mill in Japan reduced Kappa No. by 49%. Chlorine
consumption and COD in bleaching process reduced by 30% and 50% respectively.
177. Pretrealroent of Pulps with Chlorine Soteland. N.
Before Oxygen Delignification
Nordic Pulp A Paper Research
Journal. October 1988, pp.
124-127.
Slight chlorinalion of pulp oxygen delignification reduces kappa number
significantly at mill in Oslo, Norway. Results in low effluent COD, TOCI and
reduced mulagenicity.
178. Environmentally Friendly Axegard, P.
(Bleaching) Processes of the Future
TAPPI Proceedings, 1989 Bleach
Plant Operations Seminar,
Charleston. SC, March 5-9. 1989.
pp. 195-200.
Overview by STFI on ways of reducing TOCI in bleach plant effluents such as
extended delignification, oxygen delignification, chlorine dioxide substitution
and oxygen extraction. Discussion on treatment of bleach plant effluent using
recycling, membrane filtration and biological processes.
25
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TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
179. Bleaching Plants For the 90's
Idner, K.
Swedish Pulp &. Paper Journal, No.
1. 1987, pp. 50-52.
Review of alternatives for reducing TOO in bleach plant effluent* to meet
regulatory requirement!, demands for lower production costs, and improved pulp
quality. Operating costs are predicted to be lowered by increased use1 of process
control equipment and fewer bleaching stages.
180. Aerated Dike Decreases
Chlorate-Containing Effluents
Axegard. P.; Germgird, U.
Nordisk Cellulosa 3, 45:10.
December 1986, pp 56-57.
A five week aerobic treatment can diminish the environmental effect of chlorate, in
chlorine dioxide stage bleachery effluenu by 85%. The treatment, developed in
Sweden, achieved significant reductions in TOO.
181. What's Hot in Pulping? Extended
Delignification
Renard, J.J.
American Papermaker, 51:3, March
1988. pp. 50-52.
Modifications implemented at a mill in the digester operations to install extended
delignification process is described. Developments in chemical pulping
akenulives to the kraft process are briefly discussed.
182. Extended Delignificadon and Its
Potential for Environmental
Improvements
Blomberg, B.; Hauler. N.
Nordic Pulp & Paper Research
Journal No. 4, December 1986, pp.
25-29.
Improved selectivity in kraft pulping process is discussed. Most important
parameter for controlling selectivity is the lignin concentration in the cooking
liquor during final phase of cook. Swedish process discussed, which results in a low
concentration of lignin in the liquor, therefore a smaller bleaching chemical
requirement
183. Effect of Chlorine Dioxide
substitution on Bleaching
Efficiency and the Formation of
Organically-Bound Chlorine (3)
Axegard. P.
TAPPI Proceedings, 1986 Pulping
Conference, Toronto, October
26-30. 1986. Book 1. pp- 179-186.
Investigation of two alternatives for decreasing the consumption of chlorine by
using more chlorine dioxide in the bleaching sequence. Advantages of replacing the
Q which QO2 at different stages of the sequence, and ratios of formation of
different chlorates with decreased Cl consumption are discussed.
184. Oxygen Delignification as an
Alternative to Biological
Treatment: A Case Study
Galloway, L.R.; Schmid. E.; Lebidoff, Pulp A Paper Canada. 88:1, 1987. p.
J.W. T26.
A comparison of oxygen delignification and biological treatment used to reduce the
effect of kraft pulp mill effluent on receiving waters is presented here.
185. In-Plam Process Alternatives for
Minimizing Discharges of AOX
Earl. P.P.; Reeve. D.W.
Third Colloquium on Pulp and Paper
Mill Effluents, Toronto, Ontario,
February 14-15. 1989.
Process alternatives for lowering the lignin content in pulp, better washing
techniques and chlorine dioxide substitution during bleaching are discussed.
186. Chemical Inspection Agency
Charges Incorrect Dioxin
Accounting
Ekstrom. T.
Nordisk Cellulosa 5. 9:1, February
1988. pp. 15-16.
A summary of ongoing dioxin studies being done on Swedish pulp and paper mill
effluents is presented. Comparisons are shown for dioxin levels found in chlorine
dioxide stages and chlorine stages. Recent studies show that dioxin levels are just
as high in chlorine dioxide stages as in chlorine stages.
26
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGAN1CS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
187. Oxygen in • Bleaching Sequence -
An Overview
van Lierop, B.; Liebergotl, N.;
Teodoreicu. G.; Kubei. GJ.
PAPRICAN Miscellaneous Report
#57, Miy 1984
By adding oxygen to the extraction stage, the CE/O kappa number of pulps is
lowered and translate* into chemical savings in the later bleaching stages. The
inclusion of an E/O stage into a sequence without lowering the chemical charges in
later stage makes it possible to achieve higher brightness targets or decrease the
number of'bleaching stages. Installation of an E/O stage in a mill bleach plant is
straightforward and the payback has been calculated to be about six months to one
year.
188. Overview of Oxidative Bleaching LiebergoU, N.
Processes
PAPRICAN Miscellaneous Reports
#7. August 1981.
Literature relating to the use of oxidalive chemicals in the delignificalion and
brightening operations of pulp bleaching is reviewed. Experimental data on the
use of oxygen, ozone and chlorine dioxide in the chlorinadon stage and
hypocMorke, peroxide and oxygen in the extraction stages are also presented.
The use of chlorite, chlorate, peracetic acid, nitrogen dioxide, nitrogen trioxide,
nilrosyl chloride, chlorine monoxide, fluorine and oxydifluoride as pulp bleaching
agents is also discussed.
189. Evidence that Oil-Based Additives
are an Indirect Source of the TCDD
and TCDF Produced in Kraft Bleach
Plant*
Allen, L.H.; Berry, R.M.; Hemming,
B.J.; Luthe, C.E; Voss. R.H.
PAPRICAN Miscellaneous Reports
f 147, November 1988
Discuision on oil-based defoamer* as potential source of furans and dioxin found in
bleached pulp. These defoamers could result in elevated levels of 2378-TCDD and
2378-TCDF and act as carriers of the precursor compounds DBF and DBD.
190. Personal communication between
B. Brummit of E C. Jordan
Company and J. Parkinson
Parkinson, J.
Communication contains information related to costs and implementation time for
installation of chlorine dioxide generation equipment.
191. Personal communication between
B. Brummit of R C Jordan
Company and M. Freeland of CRS
Sinine, Inc.
CRS Sirrine, Inc.
Communication contains information related to costs and implementation time for
installation of oxygen delignificalion systems at Union Camp's Eastover mill.
192. Brown Stock Showers Reduce Reynolds, G.
Dioxin and More
CPPA Proceedings, 76th Annual
Meeting Technical Section,
Montreal, Quebec, February 1-2,
1990, pp. A237-A240.
Dioxin generation and soda loss can be reduced through improved brown stock
washing. The most economical way to achieve this improved washing is through
the proper application of the shower filtrate. This paper will discuss the
characteristics of the state-of-the-art shower pipe system, a case history on
improved washing through the use of this system, and the effect of shower
performance on the reduction of dioxin.
27
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TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGAN1CS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
193. Effect* of Secondaiy Treatment on
AOX Level! in Kraft Mill Effluents,
The
Dubeliten, P.; Gray. N.C.C.
CPPA Proceedings, 76th Annual
Meeting Technical Section,
Montreal, Quebec, February 1-2,
1990. pp. A317-A324.
Curtailing the release of chlorinated bleaching effluent into the environment has
become a major challenge for the Canadian pulp and paper industry. It is possible •
that this may be achieved, in part, with secondary effluent treatment. Aerated
lagoons are capable of reducing chlorinated phenolici by 20-60% and AOX by up to
one third. Improved removal efficiencies of 75-95% for the chlorinated phenolics
and 50-65% for AOX, have been observed with activated sludge treatment.
194. Hydrogen Peroxide Technology for
Chlorine Reduction
Anderson, J.R.; Cannkhael, D.L.
CPPA Proceedings, 76th Annual
Meeting Technical Section,
Montreal, Quebec, February 1-2,
1990. pp. B209-B216.
A technology for chlorine reduction involving the use of hydrogen peroxide in
conventional alkaline extraction stages is described. Mills that have used
peroxide have achieved chlorine reductions of 20-35% and have shifted operations
into a "no detectable dioxin" regime. This use of hydrogen peroxide is emerging as
an alternative technology for reduction in chlorine consumption; m addition it has
been shown to work in combination with other chlorine reduction technologies to
achieve very significant reductions in AOX level.
195. Implementation in Full Scale
Next Step for PRENOX*
• The Brannland, R.; Lindstrom, L.-A.;
Norden, S.
Sunds Defibrator
In the PRENOX process, softwood kraft pulp is treated with nitrogen dioxide. NO2,
prior to oxygen delignification. This allows for a significant decrease in the kappa
number after the oxygen stage. This paper presents results of laboratory and pilot
plant trials. Results concerning incineration of nitrogen containing black liquors
in full scale is also presented.
196. Efficient Pott Oxygen Washing -
Crucial for Low Bleach Plant
Emissions
Lindstrom, L.-A.; Norden, S.
To be given at APPITA 1990
Conference, New Zealand. April
1990.
Oxygen delignified pulp with a Kappa No of 17.7 was bleached in a C50/D50EoD
sequence. Wash losses, measured as COD, were varied from 0 -20 kgAxk. At
optimum bleaching conditions, the incremental increase of active chlorine due to
increased carry-over was estimated at 0.5-0.6 kg act. Q/bdl. AOX discharge
increased about 40% at 20 kg CODAxtt compared with completely washed pulp.
The sum of tri- and tetrachlorophenolk compounds formed during bleaching, was
roughly doubled at a high wash loss compared with completely washed pulp.
197. Oxygen Delignification - Influence
of Kappa Number After Cooking and
Degree of Delignification in the
Oxygen Stage on Yield,
Bleachabilily and Pulp Quality
Lindstrom, L.-A.
Paper presented at in INSKO
Meeting, Helsingfors, Finland,
October 12. 1989.
Oxygen delignification is playing an important role in the transformation to
bleaching systems without molecular chlorine and will do so even more pronounced
in the future. Oxygen delignification. combined with modified kraft cooking or
other emerging technologies, will make it possible to reach very low kappa
number levels prior to bleaching, and thus meet far-reaching environmental
demands on the pulp and paper industry.
198. Plant Start-up of Monox-L Generator
in KiHiiink"fki. Finland
Yam, R.; Smeds, U.; Hassi. H.
CPPA Proceedings, 76th Annual
Meeting Technical Section,
Montreal. Quebec, February 1-2,
1990. pp. B315-B319.
Recent environmental concerns and requirements have increased pressure on the
pulp bleaching industry to reduce TOCls, dioxins, and chloroform in the bleaching
process. The problem arises when pulp mills try to maintain a high-quality pulp
and at the same time, keep capital and operating costs at a minimum. Quantum has
developed the Monox-L chemical process to meet these demands. This paper
discusses the start-up of a Monox-L facility in Kuusankoski, Finland.
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ATTACHMENT A - REFERENCES
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
199. Methods to Minimize the Formation
of Lipofilic Chloroorganics in
Bleaching
Axegard. P.
TAPPI Proceeding!, 1988 Pulping
Conference, New Orleans. LA, pp.
307-314.
Conventional, oxygen delignified and PRENOX treated softwood kreft pulpi have
been bleached in the laboratoiy. The consumption of C12 and the CK)2
substitution level were varied over a large range. AOX is reduced linearly with a
decreased consumption of the elemental chlorine in molecular C12 and C1O2.
Chlorinated phenolics were found to be affected strongly by the C12 consumption.
Below a C12 multiple of about O.OS virtually no highly chlorinated phenolics could
be found.
200. Personal communication between
B.Brummit of EC. Jordan
Company and R. Sherwood of Pope
ATalbotlnc.
Pope A Talbot Inc.
Communication contains information related to capital costs and chemical cost
savings associated with oxygen extraction.
201. Unpublished data collected as part of
Pulp, Paper and Paperboard Point
Source Category Effluent
Limitations Guidelines Revision
USEPA. Office of Water Regulations
and Standards
Unpublished data
Unpublished data collected as part of Pulp, Paper and Paperboard Point Source
Category Effluent Limitations Guidelines Revision.
202. EOXEOPrebleaching: A Way to
Reduce the Formation of AOX
Lachenal, D.; Muguet, M.; Joly, P.
TAPPI Proceedings. 1990
Environmental Conference, Seattle,
Washington. April 9-11. 1990, pp.
26S-269.
Various pulps (bisulphite and kraft) were preMeached by EO x EO in which x was a
low multiple chlorinalion with partial substitution of C1O2 for C12 and EO an
oxygen treatment carried out in conditions similar to those in a conventional
oxygen reinforced extraction. Thirty percent delignification or more was achieved
after the first EO stage and full bleaching was easily obtained by adding H or D or
DED treatments. AOX formation was lower than 2 kg per ton of pulp.
203. On-Site Evaluation of a
Teflon-Based Ultraviolet Light
System and Hydrogen Peroxide for
the Degradation of Color and
Chlorinated Organics in Pine Bo
from Kraft Mill Bleach Plant
Effluents
Smith. J.E., II; Frailey, M.M.
TAPPI Proceedings, 1990
Environmental Conference, Seattle,
Washington. April 9-11, 1990. pp.
101-110.
Data collected from laboratory and field investigations showed that the UV
hydrogen peroxide process could successfully and economically remove color from .
Pine Eo filtrate. The reaction were found to be dependent on both the intensity of
UV applied to the system as well as on the concentration of hydrogen peroxide used.
An overall 80% reduction in apparent color and 85% reduction in AOX was achieved
at operating cost competitive with other technologies. The process did not produce
a sludge.
204. Environmental Aspects of
Short-Sequence Bleaching
Suss, H.U.; Eul, W.L; Nimmerfroh,
N.; Meier. J.
TAPPI Proceedings. 1990
Environmental Conference, Seattle,
Washington. April 9-11, 1990. pp.
503-513.
Low kappa factor chlorinalion, recommended to decrease the amount of
halogenaled compounds in the effluent, results in insufficient delignification. The
results of studies show that the application of oxygen delignification is more
effective in reducing halogenaled compounds than chlorine dioxide substitution.
Very low levels of halogenated compounds are the result of high-intensity oxygen
delignification followed by chlorine dioxide and hydrogen peroxide treatment.
29
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AI 1 AC'HMKINT A • KKFUKKINCKS
TECHNOLOGIES FOR THE CONTROL AND REDUCTION OF CHLORINATED ORGANICS FOR THE PULP INDUSTRY
TITLE
AUTHOR
REFERENCE
SYNOPSIS
205. AOX Reduction in Bleach Plant
Effluent tiling Enhanced Oxidation
Smith. P.W.
TAPPI Proceedings. 1990
Environmental Conference, Seattle,
Washington. April 9-11, 1990, pp.
769-772.
The use of second generation enhanced oxidation processing (HOP) designed to
reduce chlorinated phenolio (AOX) in bleach plant effluent was studied. Mill trials
were conducted in order to optimize treatment alternatives under varying production
conditions. Appropriate amount of high intensity ultraviolet light together with
chemical oxidants (ozone and H2O2) were applied to reliably reduce influent AOX
levels from 3.5-4.0 kg/tonne to 2.5 and l.S kgAonne.
206. Hydrogen Peroxide Addition to Eo
Bleaching Stages is Beneficial
Ahnouse. B.B.
Pulp & Paper, June 1988, pp. 68-70.
The addition of both peroxide and oxygen in the first extraction stage will allow
improved production at very low capital costs. Benefits include a decrease in the E
stage kappa of 10-25% with an increase in brightness of 5-15 points.
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