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A polpa kraft de Eucalyptus spp., em razão do elevado conteúdo de ácidos hexenurônicos, é relativamente fácil de ser branqueada Dessa forma, estudos têm sido feitos para diminuir o número de estágios de branqueamento na planta, minimizando assim importantes custos do processo. Este estudo teve como objetivo a avaliação de sequências curtas de branqueamento ECF (Elemental Chlorine Free) e TCF (Totally Chlorine Free): P DP (Peróxido de hidrogênio catalisado com molibdênio, seguido por estágios de dióxido de cloro e peróxido de hidrogênio), PD/P (Peróxido de hidrogênio catalisado com molibdênio, dióxido de cloro e peróxido de hidrogênio, sem lavagem entre os dois últimos estágios), PD(PO) (Peróxido de hidrogênio catalisado com molibdênio, dióxido de cloro e peróxido de hidrogênio pressurizado), D(EPO)DP (Dióxido de cloro, extração oxidativa com oxigênio e peróxido de hidrogênio, dióxido de cloro e peróxido de hidrogênio), P Q(PO) (Peróxido de hidrogênio catalisado com molibdênio, quelante e peróxido de hidrogênio pressurizado) e XPQ(PO) (Enzima, peróxido de hidrogênio catalisado com molibdênio, quelante e peróxido de hidrogênio pressurizado), com polpas kraft de Eucalyptus spp., buscando uma alvura de 90% ISO. Foram realizados estágios de branqueamento com tratamentos menos usuais tais como: peróxido ácido catalisado com molibdênio (P) e xilanase (X). Entre as sequências opcionais ECF, a sequência com dois estágios PD/P, mostrou um custo efetivo alto, no entando, sem afetar a qualidade da polpa em relação à sequência tradicional D(EPO)DP e obteve melhor qualidade do efluente também em relação à referência. Porém, a sequência de quatro estágios, XPQ(PO), alcançou a alvura desejada utilizando a tecnologia TCF. Essa sequência não teve um custo efetivo baixo, embora tenha produzido uma polpa de qualidade aceitável Eucalyptus spp kraft pulp, due to its high content of hexenuronic acids, is quite easy to bleach. Therefore, investigations have been made attempting to decrease the number of stages in the bleaching process in order to minimize capital costs. This study focused on the evaluation of short ECF (Elemental Chlorine Free) and TCF (Totally Chlorine Free) sequences for bleaching oxygen delignified Eucalyptus spp. kraft pulp to 90% ISO brightness: PDP (Molybdenum catalyzed acid peroxide, chlorine dioxide and hydrogen peroxide), MOD/P (Molybdenum catalyzed acid peroxide, chlorine dioxide and hydrogen peroxide, without washing) D(PO) (Molybdenum catalyzed acid peroxide, chlorine dioxide and pressurized peroxide), D(EPO)DP (chlorine dioxide, extraction oxidative with oxygen and peroxide, chlorine dioxide and hydrogen peroxide), Q(PO) (Molybdenum catalyzed acid peroxide, DTPA and pressurized peroxide), and XP Q(PO) (Enzyme, molybdenum catalyzed acid peroxide, DTPA and pressurized peroxide). Uncommon pulp treatments, such as molybdenum catalyzed acid peroxide (P ) and xylanase (X) bleaching stages, were used. Among the ECF alternatives, the two-stage P D/P sequence proved highly cost-effective without affecting pulp quality in relation to the traditional D(EPO)DP sequence and produced better quality effluent in relation to the reference. However, a four stage sequence, XPQ(PO), was required to achieve full brightness using the TCF technology. This sequence was highly cost-effective although it only produced pulp of acceptable quality

Oil Palm Trunk (OPT) is a non-wood cellulosic raw material which is not yet widely utilized in pulping and papermaking. Research on the utilization of abundant Oil Palm Trunk (OPT) from Sabah (Malaysia) and Lebak (West Java Province) for pulp production was carried out using kraft and soda anthraquinone processes with active alkali (AA) of 13-17%. The raw material was chipped and depithed as pretreatment. Bleaching of pulp was carried out using Elemental Chlorine Free (ECF) process. Analysis of raw material covered physical and chemical properties, and fiber morphology. Both OPT fibers were classified into the moderate fiber length (1.05-1.37 mm). Sabah OPT were very bulky with the chips pile density of 102.16 kg/m3 and 62.91 kg/m3 for undepithed and depithed OPT, respectively. The physical properties of OPT pulps were comparable to that of Acacia mangium pulp. With respect to the bleachability and physical properties, pulping of Lebak OPT using kraft or soda-anthraquinone process with AA of 15% were considered as optimum condition. Depithing on Sabah OPT with high pith content could increase physical properties of pulp. ODEoDnD bleaching sequence on pulps from Sabah OPT gave satisfactory results with respect to the physical properties. Since Sabah OPT had a high pith content, the yields of bleached pulp were relatively low (24.67-26.73%). However, the physical properties of the undepithed and depithed Sabah OPT bleached pulp were higher compared to those of the SNI of Leaf Bleached Kraft Pulp (LBKP).Keywords: depithing, Elemental Chlorine Free, bleached pulp, physical properties, LBKP Pengaruh Variabel Proses Pulping dan Pemutihan Elemental Chlorine Free pada Kualitas Pulp Batang Kelapa SawitAbstrakBatang Kelapa Sawit adalah bahan baku selulosa non-kayu yang belum banyak digunakan dalam pembuatan pulp dan kertas. Penelitian tentang pemanfaatan Batang Kelapa Sawit (BKS) dari Sabah (Malaysia) dan Lebak (Provinsi Jawa Barat) yang berlimpah untuk produksi pulp menggunakan proses kraft dan soda antrakuinon dengan alkali aktif (AA) kisaran 13-17% telah dilakukan. Penyerpihan dan proses depithing bahan baku dilakukan sebagai perlakuan awal. Pemutihan pulp dilakukan menggunakan Elemental Chlorine Free (ECF). Analisis bahan baku mencakup sifat fisik dan kimia, serta morfologi serat. Kedua serat BKS dapat diklasifikasikan sebagai serat moderat dengan panjang 1,05-1,37 mm. BKS dari Sabah sangat ruah dengan densitas tumpukan serpih masing-masing 102,16 kg/m3 untuk yang belum di-depithing dan 62,91 kg/m3 untuk yang telah di-depithing. Sifat fisik pulp BKS sebanding dengan pulp dari Acacia mangium. Sehubungan dengan kemampuan pemutihan dan sifat fisik, pembuatan pulp BKS dari Lebak menggunakan proses kraft atau soda-antrakuinon dengan AA 15% adalah kondisi optimal. Depitihing BKS dari Sabah dengan kandungan pith yang tinggi dapat meningkatkan sifat fisik pulp. Pemutihan dengan urutan ODEoDnD untuk pulp BKS dari Sabah memberikan hasil sifat fisik yang memuaskan. BKS dari Sabah memiliki kandungan pith yang tinggi sehingga rendemen pulp yang diputihkan relatif rendah (24,67-26,73%). Namun, sifat-sifat fisik pulp putih BKS dari Sabah yang belum dan telah di-depithing lebih tinggi dibandingkan SNI Pulp Kraft Putih Kayudaun (LBKP).Kata kunci: depithing, Elemental Chlorine Free, pulp putih, sifat fisik, LBKP

BACKGROUND: The process of chemical pulp bleaching is based for the most part in chlorine dioxide within elemental chlorine free (ECF) technologies. The use of greener alternatives such as bleaching with hydrogen peroxide (P stage) is not widely used owing to selectivity concerns related to transition metal-catalyzed decomposition reactions. Even at the final stage where peroxide is recognized to boost brightness and improve the brightness stability of the bleached pulp, cellulose degradation often overcomes these advantages. This paper presents the results of studies intended to optimize final peroxide bleaching performance considering two standard ECF industrial bleaching sequences: the conventional DED and the ECF-light OQ(PO)D (stages name: D—chlorine dioxide; E—alkaline extraction; O—oxygen; Q—chelation, (PO)—hydrogen peroxide pressurized with oxygen). RESULTS: The addition of sodium diethylenetriaminepentaacetate (DTPA) was the most effective option in terms of DED pulp bleachability and selectivity with hydrogen peroxide, as well as in terms of brightness reversion. As regards the OQ(PO)D pulp, a blend of DTPA and magnesium was the most beneficial in those properties. CONCLUSIONS: The choice of the best hydrogen peroxide stabilizer, among the different tested combinations of magnesium and chelants (EDTA and DTPA) studied, in terms of pulp bleachability, bleaching selectivity and brightness reversion is dependent on the impact of the previous bleaching stages on metallic nature and content. The pulp Mg/(Fe + Cu) ratio was highlighted as a process parameter controlling cellulose degradation in peroxide bleaching. Copyright © 2010 Society of Chemical Industry

Our previous investigation [1] re-analyzed the data from Basta and co-workers (1992 TAPPI Pulping Conference) to demonstrate how oxidative alkaline extraction can be augmented and how these changes affect chlorine dioxide consumption with elemental chlorine-free (ECF) sequences. The current study manipulates extraction delignification variables to curtail bleaching costs with a conventional U.S. Southern softwood kraft pulp. The economic advantages of ~0.35% to 0.65% H2O2 peroxide reinforcement in a 70°C (EOP)-stage versus 90°C (EO)-stage are predisposed to the brightness targets, to short or long bleach sequences, and to mill energy costs. Minimized bleaching costs are generally realized when a 90°C (EO) is employed in D0(EO)D1 bleaching, whereas a 70°C (EOP) is economically advantageous for D0(EOP)D1E2D2 bleaching. The findings we disclose here help to clarify previous ECF optimization studies of conventional softwood kraft pulps.

The present investigation meticulously analyzes how oxidative alkaline extraction can be augmented through process changes, and how these augmentations can be leveraged to optimize chlorine dioxide usage with elemental chlorine-free (ECF) sequences for a conventional softwood kraft pulp. Bleaching data from Basta and co-workers (1992 TAPPI Pulping Conference) are re-examined and re-interpreted in this study. We determined that ~60% to 65% of the overall ClO2 charge should be applied in the D0-stage. Peroxide addition to an (EOP) can replace 0.6 to 2.5 Kg. ClO2 per Kg H2O2. Boosting the (EO) temperature to 80°C is equivalent to a 70°C (EOP) with 0.25% to 0.30% H2O2,whereas a 90°C (EO) is equivalent to 0.50% – 0.75% H2O2 in a 70°C (EOP). The stoichiometric bleaching data from this study can guide decision-making for lowering chemical usage and minimize costs to reach target brightness levels with three- and five-stage sequences.

Halfa, also known as Stipa tenacissima, is grown in North Africa and south Spain. Due to its short fiber length, paper of halfa remains bulk and takes the block letters well. In this study halfa was evaluated for bleached pulp production. Two cellulose pulps with different chemical compositions were pulped by conventional Kraft process: one from the original halfa material and the other from halfa pretreated by diluted acid. The pulp produced from halfa pretreated by diluted acid was bleached by elemental chlorine-free sequences, DEPD and DEDP. Yield, Kappa number, brightness and α-cellulose contents of bleached and unbleached pulps were evaluated. The results show that during the chemical pulping process, treated halfa was easily cooked than that original halfa. Treated halfa pulp also showed very good bleaching, showing brightness level of 94.8% ISO, yield 93.6% and α-cellulose content 96.8% with DEDP bleaching sequence compared to 83.2% ISO brightness level, 92.8% yield and 95.1% α-cellulose content for bleached pulp with DEPD bleaching sequence. On the other hand, the physicomechanical properties of pulp were not notably reduced by the bleaching process. Breaking length, tear and burst index of paper sheets were acceptable. Therefore, this halfa material could be a worthwhile choice for cellulosic fiber supply.

パルプの塩素漂白により発生する有機塩素化合物の多くは難分解性，蓄積性に加えて毒性を示すことが知られている。この有機塩素化合物の削減を目的として日本の製紙会社は1996年から漂白工程のECF転換を進めてきた。日本紙パルプ研究所では王子製紙，日本製紙のECF転換の進行に合わせ，排水による環境負荷を調査してきたが，その過程で明らかになったクロロホルムとクロロフェノール類の削減状況を報告する。漂白工程でのクロロホルム発生は広葉樹パルプ漂白系でパルプ1t当たり平均46g（g／t）から0．50g／tに，針葉樹パルプ漂白系で平均43g／tから0．55g／tへ95％以上減少し，漂白工程のECF転換の主要な目的であったクロロホルムの発生抑制は十分達成された。総合排水での排出濃度も発生の削減をうけ激減し，水道水質基準の0．06mg／Lをも下回るようになった。塩素漂白により発生する有害性の指摘される3塩素化以上のクロロフェノール類も，ECF転換によって発生はほぼ100％削減され，米国EPAのクラスタールールが求める漂白排水のクロロフェノール類の規制をクリアするレベルとなった。

Total chlorine free (TCF) and elemental chlorine free (ECF) bleaching sequences were applied to an Arundo donax L. (giant reed) unbleached kraft-anthraquinone pulp, using different sequences with hydrogen peroxide and chlorine dioxide stages. The evolution of ISO brightness, kappa number and pulp viscosity was observed for each stage in all bleaching sequences, as well as the process selectivity. The best results were obtained with the XOQDP sequence with a final ISO brightness of 80%. The effect of a chelating stage before the hydrogen peroxide stage was studied, and the results showed higher pulp viscosity, less peroxide consumption and higher pulp brightness, when this treatment is applied.

In the process of making high quality pulp from wood chips, much water will continuously be needed. The fate of the used water with the organic and inorganic impurities remains optional. Mills with zero liquid effluent have been mentioned as the target in environmental loading minimization of pulp and paper mills with hardly any debate. To avoid inappropriate solutions when approaching this target, thorough knowledge of loading element behavior in liquid streams of production processes should be available before decisions are made for development alternatives. Based on empirical measurements of dissolved organic matter (DOM) in liquid streams of fiberline and utilizing them together with routine mill data in process simulation, this study aims at mapping DOM and its fate in elemental chlorine free (ECF) softwood kraft pulp production. The results of this study act as a demonstration for determining the essential fates and their quantities in the ECF fiberline.

Paper industries using different raw materials such as hard wood, bamboo, baggase, rice-straw and waste papers and bleaching chemicals like chlorine, hypochlorite, chlorine dioxide, hydrogen peroxide, sulphite and oxygen were studied to estimate organic pollution load and Adsorbable Organic Halides (AOX) per ton of production. The hard wood based paper industries generate higher Chemical Oxygen Demand (COD) loads (105-182 kg t(-1)) and Biochemical Oxygen Demand (BOD) loads (32.0-72 kg t(-1)) compared to the agro and waste paper based industrial effluents. The bleaching sequences such as C-EP-H-H, C-E-H-H, C-E-Do-D1 and O-Do-EOP-D1 are adopted in the paper industries and the molecular elemental chlorine free bleaching sequence discharges low AOX in the effluent. The range of AOX concentration in the final effluent from the paper industries was 0.08-0.99 kg t(-1) of production. Water consumption was in the range of 100-130 m(3) t(-1) of paper production for wood based industries and 30-50 m(3) for the waste paper based industries. Paper machine effluents are partially recycled after treatment and pulp mill black liquor are subject to chemical recovery after evaporation to reduce the water consumption and the total pollution loads. Hypochlorite bleaching units of textile bleaching processes generate more AOX (17.2-18.3 mg l(-1)) and are consuming more water (45-80 l kg(-1)) whereas alkali peroxide bleaching hardly generates the AOX in the effluents and water consumption was also comparatively less (40 l kg(-1) of yarn/cloth).

日本の製紙産業はAOX自主規制値を設定し，漂白パルプ製造プロセスや排水処理設備を改善することによってダイオキシン問題を解決してきたが，1996年の改正大気汚染防止法を契機に，有機塩素化合物のさらなる自主的削減策として無塩素（ECF）漂白の導入が進んだ。その結果，2006年には漂白パルプの80％以上がECF漂白によって製造されるまでになった。ECF漂白を採用することにより，環境影響が懸念されているクロロホルム，クロロフェノール類，ダイオキシン類などの有機塩素化合物の漂白工程における発生量が著しく減少した。その結果，全有機塩素化合物の指標であるAOXは工場からの排出量が大幅に減少し，排出原単位は0．2kg／t以下にまで低下した。一方，二酸化塩素漂白の採用でクロレートの排出量が増加した。ECF漂白へ転換することによって排水の水生生物への影響が変化するかどうかに関しては，現在日本紙パルプ研究所で評価中である。パルプ漂白に関する有機塩素化合物の問題はECF漂白への転換によって一応の解決をみたが，製紙産業としては今後も継続的な環境対策を進めていくことが重要である。

A laboratory investigation was developed to confirm and to quantify the reductions in absorbable organic halide (AOX) discharge when sodium sulphide was added during elemental chlorine-free (ECF) bleaching of sugarcane bagasse pulp. After the chlorine dioxide bleaching stage, the pulp was sent directly into the extraction stage without washing. FTIR was employed to determine the breakage of chemical bonds in the pulp, and GC-MS was used to measure the composition of the bleaching effluent. The addition of sodium sulphide caused a reduction in AOX of up to 46.7%. The AOX reduction reached this maximum when the sodium sulphide was added 30 min after the start of the extraction stage and when the pH was higher than 12. FTIR spectroscopy showed that the phenolic lignin of the pulp was degraded by the sodium sulphide and that the syringyl lignin and C-O-C, C=O structure of the pulp holocellulose of the pulp was preserved during the extraction stage. The GC-MS showed that the chlorobenzene and chlorophenol contents decreased noticeably after the addition of sodium sulphide.

This study outlines the results of a biobleaching study of acacia (A. mangium) and eucalyptus (E. globulus) hardwood kraft pulps with commercial xylanase (Optimase CX 72 L). The comparative study was carried out using an elemental chlorine-free (ECF) bleaching sequence (D0EPD1D2) after the enzyme (X) stage. The enzyme treatment resulted in improved optical properties with a reduction in bleach chemical consumption. At an equivalent bleach chemical consumption, a brightness gain of 2.1 and 1.7 units and a whiteness gain of 2.7 and 2.3 units were observed with xylanase treatment in acacia and eucalyptus pulps, respectively. In ECF bleaching using the D0EPD1D2 sequence, a final brightness was achieved to the extent of 90% ISO and 89% ISO for acacia and eucalyptus, respectively, at an equivalent charge of bleach chemicals. The post-color (PC) number was also reduced by up to 45% for both hardwood pulps compared with the control. The bleachability of acacia was observed to be significantly higher than that of eucalyptus. In addition, a 17.0% and 23.0% reduction in chlorine dioxide and sodium hydroxide, respectively, were obtained for both hardwood pulps after xylanase pre-bleaching, thus indicating an environmentally friendly approach to the process.

Kraft pulp mill effluents contain elevated concentrations of resin acids, chiefly abietic and dehydroabietic acid, and other lipophilic wood constituents. Resin acids, if not efficiently removed during wastewater treatment, can be responsible for chronic toxicity in aquatic systems. The objective of this study was to investigate the biological removal of abietic acid (AbA) during the treatment of elemental chlorine free (ECF) kraft mill effluents in aerobic lagoons and to assess its improvement with time as a result of biomass adaptation. Under these conditions, the average removal efficiencies of AbA and BOD5 attained in the aerobic lagoon were high and exceeded 80% and 95%, respectively. Microbial inhibition of non-acclimated and acclimated biomass by AbA was not detected in batch bioassays. Kinetic studies showed that the Ks and Vm values equalled 76.7 mg AbA/l and 0.011 l/h, respectively, for the non-acclimated biomass, and 1678 mg AbA/l and 0.13 l/h, respectively, for the acclimated biomass. © 2005 Elsevier B.V. All rights reserved.

The delignification efficiency of different laccase enzymes was examined on the eucalyptus Kraft pulp. The laccase enzyme from Trametes versicolor showing the highest delignification efficiency was selected and used in the elemental chlorine-free bleaching sequence for improving the pulp bleachability. A n appreciable reduction in chlorine dioxide consumption was also obtained. Further reduction in chlorine dioxide consumption was obtained when the same laccase treated pulp was subjected to an acid treatment after the extraction stage followed by the DE P D sequence. Elemental-chlorine free bleaching was also performed using the xylanase-laccase treated pulp. Xylanase treatment was incorporated to the laccase mediator system in the elemental-chlorine free bleaching both sequentially and simultaneously. The bleaching sequence DE P D followed and in both the cases, the reduction in chlorine dioxide consumption was greater in comparison to the control. The chlorine dioxide consumption was reduced further when xylanase-laccase treated pulp was given an additional acid treatment. The final pulp properties of the treated pulps were comparable to the control pulp.

Totally chlorine free (TCF) and elemental chlorine free (ECF) single and multistage sequences were used to bleach whole stem kenaf pulp. The results indicated that in contrast to unbleached kraft wood pulps, kraft kenaf pulps can be easily bleached to a brightness of 91.4% using a four-stage TCF [Q1(PO)Q2P] bleaching sequence. The ECF bleaching pulps had slightly higher selectivity and yield than those of the TCF bleached pulps. The strength properties of the TCF [Q1(PO)Q2P] and ECF (D1ED2EP) bleached pulps were comparable, with the exception of tear index and tensile index, which were slightly higher and lower for TCF pulps, respectively.

Background, Aim and Scope At present, large-scale paper manufacture involves delignification and bleaching by elemental chlorine free (ECF) or totally chlorine free (TCF) processes. The wastewater is purified by secondary treatment (mechanical, chemical and biological) which removes most of the toxic substances from the discharge. However, we found residual toxicity in the high molecular (> 1000 D) matter (HMWM) of the discharge by test of the RET (reverse electronic transfer) inhibition. This fraction consists mainly of polydisperse lignin (LIG) and carbohydrate (CH) macromolecules. Structural units in these molecules are studied by pyrolysis gas chromatography / mass spectrometry (Pyr-GC/MS). In the present work, our aim was to find out those structural units which could explain the RET toxicity of LIG or CH molecules. We compared statistically RET toxicity values of the HMWM samples from treated wastewaters of pilot pulping experiments and intensity variation of the pyrolysis product gas chromatograms of these samples. This application is a novel study procedure.

Goal and Background The LCA methodology is used to compare the potential environmental benefits of an emerging biotechnology, enzyme-bleaching, with those of elemental chlorine free (ECF) bleaching, an existing technology that is widely used in paper making. Through the use of biodegradable enzymes to supplement, or eventually to replace, chemicals in the bleaching process to extract lignin, enzyme bleaching processes are aimed to reduce the use of chlorine based bleaching chemicals and to achieve cost savings by circumventing investment into oxygen delignification or ozone bleaching technology.

The wastewater treatment plant of an elemental chlorine free bleaching kraft pulp mill located in eastern Finland was sampled in order to study the fate of wood extractives and the toxicity to luminescence bacteria (Vibrio fischeri) in different parts of the plant. Resin acids and sterols were analyzed from water, particles and sludge samples during three different runs. Waters before biotreatment and primary sludge were found to be toxic; but in the activated sludge treatment toxicity was removed. During wastewater treatment, concentrations of wood extractives were reduced over 97%. In activated sludge treatment, over 94% of the resin acids and over 41% of the sterols were degraded or transformed to other compounds. Furthermore, in general, less than 5% of the resin acids and over 31% of the sterols were removed in biosludge to the sludge thickener. Most of the extractives were discharged attached to particles. Although some disturbing factors increased the load of wood extractives during samplings, these factors did not affect the operational efficiency of the secondary treatment system.

The effluent from pulp bleaching processes containing chlorinated lignin and degraded polyphenolic intermediates remains as a major source of water pollution from the pulp and paper industries. Alternative elemental chlorine free bleaching methods based on the usage of chlorine dioxide, ozone and hydrogen peroxide are potential substitutes. Bio-bleaching methods, which involve pre-treatment of pulp with microbial enzymes such as xylanases, have emerged as viable options. Investigations reported in this paper aim at exploring the suitability of commercial bacterial xylanase enzyme preparations for bio-bleaching of bagasse pulps in conjunction with specific chemical bleach sequences employing hydrogen peroxide (P), alkali extraction (E), ozonation (Z), hypochlorite (H) and chelation (Q) stages. The effluent profiles and pulp qualities obtained for each of the bleach combinations (involving bio-bleaching and chemical bleaching sequences) were monitored. Analysis of the results clearly indicates that the inclusion of enzyme pre-treatment with the TCF (total chlorine free) and ECF (elemental chlorine free) sequences has a significant effect on the effluent (COD, lignin and colour) and pulp quality (kappa number, brightness) parameters. In conclusion, the findings of this investigation indicate the potential promise of enzyme pre-treatment in combination with chemical bleaching to enhance the quality of pulps and combined effluents.

Kraft pulp and sulfite pulp bleaching mills using chlorine, chlorine dioxide (D) and other chlorinated compounds are under surveillance of the dioxins regulation in Japan. One of questions is whether water qualities of process sewers in chlorine dioxide bleaching (Elemental Chlorine-free bleaching: ECF bleaching) mills are less than the environmental water quality (1pg-TEQ/L) or not. Objectives of this report are to review studies about the dioxins level of ECF mill sewers and model experiments from an aspect of the environmental water quality. Laboratory bleaching were carried out using a mill hardwood oxygen-bleached kraft pulp (LOKP), chlorine dioxide from a mill R 8 generator in a laboratory high-share mixer. Active chlorine factors were in the range of 0.14-1.14. In all cases, 2, 3, 7, 8-TeCDD and 2, 3, 7, 8-TeCDF were not detected for the pulps and spent liquors. Examination of process water from an ECF bleaching line in Niigata mill of Hokuetsu Paper Mills, LTD. shows that the concentrations of the dioxins in both sewers of the chlorine dioxide stage (D0) and the alkali stage (E/O) were below 1pg-TEQ/L, and that the 2, 3, 7, 8-TCDF concentrations were 0.41pg/L or less. In addition, a main source of 1, 3, 6, 8- and 1, 3, 7, 9-TeCDD in the process water seemed to be an agrochemical in water supplied from a river.In the meantime, Japan revised the Air Pollution Control Law in 1996. The main purpose of the law is to reduce discharge of toxic pollutants such as carcinogenic substances into the air. The Japan Papermaking Association estimated the nationwide chloroform discharge to air for the fiscal year 1996 at 1, 655 t on the basis of field studies, and initiated a reduction of the discharge. As a result, the estimated discharge was reduced to 1, 118 t, which was a reduction of 32%, for the fiscal year 1999. However, further reduction is required because there is still much discharge. We estimated chloroform formation and discharge in the mill having an ECF bleaching line and a chlorine bleaching line as well as an effluent treatment process. It was clarified that the chloroform formation in ECF bleaching was approximately one eightieth of that in chlorine bleaching.

With the implementation of the Cluster Rule in the United States, all bleached grade kraft pulpmills required to meet stringent levels of absorbable organic halides in the effluent. The method most used to meet the absorbable organic halide levels was to convert to 100% substitution of chlorine dioxide in the predominately C or CD first stage. As mills substituted chlorine dioxide in the first stage the bleachplant, thereby converting to elemental chlorine free (ECF) bleaching, several key parameters were impacted. Two of these were that delignification in ECF was less than partial substitution of chlorine dioxide in the chlorine stage and secondly the increase in pH in the first stage did not give the level of metals solubility as compared to chlorine or CD bleaching. Metals management has become a significant issue in ECF bleaching as metals that previously had a minor influence in bleaching create issues with inorganic deposition and efficiency reduction of peroxide bleaching. Several operating conditions have been identified that when optimized, reduced the issues associated with scale development in various stages of the bleachplant.

Scaling troubles of calcium oxalate are observed frequently in ECF (elemental chlorine free) bleaching process at a kraft pulp plant. Phenomena of the scale formation is very complicated which includes simultaneous nucleation, dissolution, growth and/or adhesion of crystals. The scale formation tendency can be predicted by a saturation index (SI) calculated by pH and concentration of scaling species.Scale inhibitor shows effects such as nucleation prevention, crystal distortion and suspended solid dispersion. For scale inhibitor treatment, a critical saturation index (CSI) is defined as a maximum SI which shows no nucleation at some inhibitor concentration.ECF bleaching process has a tendency to show higher SI compared with a conventional bleaching. At a washing filter of chlorine dioxide stage in ECF process. CSI optimized “Depoclean” treatment shows a stable operation without scaling trouble.

The effect of Eucalyptus globulus wood kraft pulping conditions on the chlorine dioxide consumption in elemental chlorine free bleaching of pulps was investigated. When the pulping is extended (kappa number decreases), the bleachability [as (OXE/ton)/kappa number] is reduced, suggesting that residual lignin and other oxidizable unsaturated structures in pulp become less reactive as their content in the pulp decreases. For the same unbleached pulp kappa number, the increase in active alkali and sulfidity used in pulping improves bleachability, whereas the pulping temperature (150-170°C) does not affect the bleaching response. The increase in liquor-to-wood ratio has a detrimental effect on the bleachability. No clear correlation could be established between unbleached pulp brightness and its bleaching response. Overall, the results obtained show a good correlation between the integral of the relative reaction rate constant (H factor) used in the pulping and pulp bleachability, with a low H factor being beneficial to the bleaching response of the pulp.

In present study, xylanase and laccase were produced in a cost-effective manner up to 10 kg substrate level and evaluated in elemental chlorine free bleaching of Eucalyptus kraft pulp. Compared to the pulp pre-bleached with xylanase (15%) or laccase (25%) individually, the ClO2 savings were higher with sequential treatment of xylanase followed by laccase (35%) at laboratory scale. The sequential enzyme treatment when applied at pilot scale (50 kg pulp), resulted in improved pulp properties (50% reduced post color number, 15.71% increased tear index) and reduced AOX levels (34%) in bleach effluents. The decreased AOX level in effluents will help to meet AOX discharge limits, while improved pulp properties will be value addition to the paper.

Sediment constitutes an important sink of endocrine disruptor compounds; however, the potential of sediments to act as a source of endocrine disruptors should be more extensively investigated. The main objective of this study was to determine whether exposure of immature common carp to Uruguay River sediments undergo physiological and endocrine alterations. The lower Uruguay River watershed supports intensive agricultural and forest production, receives municipal sewage discharge and industrial effluent, and a new large pulp mill was constructed in 2006. A 30-day semi-static assay was performed using sediments from four sites along the Uruguay River and compared with an unexposed group in dechlorinated water as a negative control. We focused on two upstream and two downstream sites of a new elemental chlorine free pulp mill. The results showed that plasma vitellogenin levels increased in fish along the river and significant differences were found between the exposed and unexposed groups. Condition factor and gonadosomatic index were not different; however, a significant difference in hepatosomatic index was observed in fish exposed to sediment from an industrial site. A significant reduction in primary spermatocyte accumulation was observed in the exposed group compared with that in the control group, and some individuals exposed to sediments from industrial sites presented with testis–ova. Our results suggest that Uruguay River sediments act as an important source of estrogenic compounds that could be responsible for the alterations observed. Future studies are needed to identify the causal agents and determine exposure routes.

Peracids are strong oxidant species and their use is being largely studied in the delignification and cellulose pulp bleaching. Some of them has already an industrial application, specially in non-conventional bleaching sequences like ECF (Elemental chlorine free) and TCF (Totally chlorine free). This review presents the main aspects of the structure, properties, preparation and reaction of peracids (peracetic acid, peroxymonosulfuric acid and their mixture) with lignin, specially for peracetic acid. Information about bleaching and delignification of wood pulps with peracids and the factors affecting its efficiency are also presented.

Fibres from conventional pine kraft pulp (KP), oxygen-delignified KP (KPO) and elemental-chlorine-free (ECF) bleached KP were characterized by scanning probe microscopy (SPM). The surface morphology of lignin isolated from the respective pine KP was studied. The data analysis of the phase-shift data measured by using different tapping mode imaging parameters enabled the study of both the surface amphiphility and stiffness as a function of delignification. The average phase-shift values were observed to correlate to the respective kappa values, when imaging with small tapping amplitude (30 nm), referred to the capability of SPM to follow local amphipilic (adhesion) differences on a wood fibre surface. The roughness (standard deviation) of the average phase-shift values was taken as a measure of the sample homogeneity. The mean morphological roughness was observed to increase with decreasing bulk lignin concentration. The surface of lignin appeared mainly granular but occasionally some linear structures were observed. The surface roughness of different fractions of flow-through residual lignin samples correlated quite well to the molar mass of the respective fraction. Each grain contained hundreds of lignin molecules. Most of the lignin samples were homogeneous as regards friction and phase-contrast images. The surface of the nondelignified pine KP was typically granular. ECF delignification was more effective than oxygen delignification in removing this granular phase. The decrease in the relative amount of the granular phase correlated to a decreasing kappa value of the pulp. The granular phase is thus suggested to correspond to lignin, but it cannot be ruled out that small amounts of hemicellulose, extractives or a mixture of these components are embedded in this phase. The surface concentration of the granular phase of the KPO samples was, according to the phase-contrast images, clearly higher than the bulk lignin concentration, as indicated by the corresponding kappa values.

The potential of crude xylanase from Thermomyces lanuginosus and Xylanase P (a commercial xylanase) was evaluated in bleaching of various paper pulp types. Xylanases released chromophores and reducing sugars and decreased kappa number of pulps. Chlorine-bleached, alkali-extracted bagasse and post-oxygen kraft pulps, pretreated with enzymes, gained over 5 brightness points over controls. Biobleaching of soda-aq pulp with Xylanase P produced chlorine dioxide savings of up to 30% or 4.5 kg chlorine dioxide t−1 pulp.

The use of a novel ‘‘xylanase A’’ enzyme was found beneficial in the elemental chlorine free (ECF) bleaching of oxygen delignified Eucalyptus kraft pulps. The application of the enzyme made possible production of fully bleached pulps with high brightness (89% ISO) and viscosities (above 800 cm 3 /g), without elemental chlorine (XDnEpD and DnEpD sequences) at low chlorine dioxide consumption. As a result of the enzyme treatment, morphological changes such as cracks, flakes, filaments and peeling of the fibre cell wall were observed by SEM (scanning electron microscopy). These modifications of the fibre surface facilitated the access to the fibre cell wall for the successive bleaching with less chemicals. ” 2000 Elsevier Science Ltd. All rights reserved.

The concentration of retene, a di-alkyl substituted PAH derived microbially and thermally from dehydroabietic acid, eight resin acids and their derivatives were analysed from sedimenting particles collected from five lake sites receiving pulp and paper mill effluents and from two reference sites. At five of the sites, samples were collected prior and after a conventional aerated lagoon wastewater treatment system of the mill was modernized with an activated sludge plant, and elemental chlorine free bleaching (ECF) had replaced chlorine bleaching. The highest level of retene was 30.0–53.8 μ g/g dry weight (d.w.), observed 3 km downstream from the mill. Nine kilometers downstream from the mill the concentration of retene was still 8.7–17.4 μ g/g d.w., distinctly exceeding that of the upstream reference (0.2–4.4 μ g/g d.w). The highest concentration of resin acids was 1474 μ g/g d.w., the most abundant resin acid being dehydroabietic acid. The concentrations of retene and resin acids showed a distance related decrease downstream to a mill. The technology changes at the pulp and paper mill decreased both the sedimentation rate and the concentration of resin acids and retene in sedimenting particles. Presence of other resin derived neutral compounds (dehydroabietin, tetrahydroretene and fichtelite) in sedimenting particles was also revealed.

The present study was designed to assess the effects of elemental chlorine free (ECF) and totally chlorine free (TCF) pulp and paper mill effluents on the immune defence of the roach ( Rutilus rutilus ). Fish were exposed for 5 weeks to concentrations of 0, 0.6, 2, 6 and 20% of untreated effluents from ECF or TCF bleaching processes. In order to study the capability to respond to foreign antigens the fish were immunised with bovine γ-globulin (BGG) 3 weeks before sampling. The numbers of anti-BGG antibody-secreting cells and immunoglobulin-secreting cells in the spleen and blood, as well as the levels of the anti-BGG antibodies and concentrations of immunoglobulin in plasma and the proliferation of lymphocytes after mitogenic activation were determined. In addition, phagocytosis-related functions, respiratory burst activity and migration of leukocytes, were measured. Formation of specific anti-BGG antibody-secreting cells in the blood and immunoglobulin-secreting cells in the spleen and blood were suppressed in the fish exposed to a high concentration (20%) of ECF effluent. Similarly, the level of anti-BGG antibody and the stimulation indices of Concanavalin A-stimulated proliferation responses in vitro were lower in these fish. A decreased migration of granulocytes was observed in the fish exposed to 0.6–2% of ECF and TCF effluents. These results demonstrate that untreated ECF and TCF effluents significantly affected the immune parameters of the roach. Taken as a whole, fish exposed to TCF effluent showed less immunomodulation than those exposed to EFC effluent.

The toxicity of nine effluents from Swedish kraft-pulp mills using conventional, elemental chlorine-free (ECF) and totally chlorine-free (TCF) bleaching processes was studied. Effluents represented six different processes: conventional-softwood 30% ClO2; ECF-softwood; TCF-hardwood, for which all the samples were taken before and after secondary treatment; conventional-softwood 8% ClO2; TCF-softwood O3/H2O2; and TCF-softwood H2O2. Comparison of effluents, which had not undergone secondary treatment, suggested that those from mills using conventional bleached pulp were the most toxic, with toxic emission factors (TEF) ≈ 1,000 according to the Microtox® test (AZUR Environmental, Carlsbad, CA, USA). In the acute Nitocra spinipes test, the conventional-softwood 8% ClO2 and the ECF-softwood effluents before secondary treatment were the most toxic, with TEF ≈ 700. In the reproduction test, N. spinipes was two to three times more sensitive than in the lethal test. The species most sensitive to the effluents investigated was the macroalga Ceramium strictum, with TEF values up to 3,000. The conventional effluent using a substitution of 8% ClO2 was the most toxic, and the TCF effluents were the least toxic. Degradation treatment of the ECF and TCF effluents for 28 d in the laboratory did not eliminate acute lethal effects on N. spinipes and the Microtox bacterium.

Since many studies have pointed out ECF (Elemental Chlorine Free) as environmentally friendly with no harmful by-products and no specific toxicity of the resulting waste waters compared to TCF (Totally Chlorine Free); ECF bleaching is now considered all over the world as a Best Available Technology. Most of the incoming projects over the world are based on ECF bleaching and world ECF bleached pulp shate is still growing since it took the leadership in 1996. About 38 Mt of pulp was ECF bleached in 1997, 33 Mt was ECU (elemental chlorine used) bleached and 4 Mt was TCF bleached.Whatever wood species considered, transfer to ECF technology is easily achievable with respect to brightness and mechanical properties goals while minimising the quantity of organohalogenated by-products. Western Europe has almost completely turned to ECF and with the new Cluster Rules regulation (November 1997), NORTH AMERICA pulp mills still using chlorine are moving to ECF.To summarize we can conclude that moving to ECF technology is the best economical way to minimize pollutant and organohalogenated emissions with low investment cost and taking care of pulp properties. ECF is also the bleaching technology which will allow us to meet the year 2000 minimum mill effluent challenge.

A preliminary investigation on the contribution and origin of organic halogens (measured as AOX) in sludges out of pulp and paper production is described. Size exclusion chromatography (SEC) and indirect enzyme-tests (cellulase) have shown remarkable differences in AOX-substances between various fractions of paper sludges. In sludges from factories with 100% pulp usage (pulp sludges) chlorinated polymers from the pulp bleaching with chlorine were identified as main source. In sludges from companies with 100% waste paper usage (waste paper sludges) strong indication has been presented that the main AOX-sources are contaminations in printing inks and smaller fragments of chlorinated wood polymers, especially lignin. For the improvement of paper sludge disposal in Europe (especially Germany) it is important to decrease the AOX-contents by substitution of AOX-containing printing inks and by transforming the traditional chlorine bleaching of pulp to elemental chlorine free (ECF) or total chlorine free (TCF) processes.

The most abundant volatile organochlorine compounds (VOCCs), trichloroacetic and dichloroacetic acids and AOX, were determined in bleaching effluent and waste water from three kraft pulp mills during ClO2 bleaching. 0.6–7.7 g of VOCCs per ton bleached pulp were formed, the most abundant being chloroform and dichloroacetic acid methyl ester. Most of the VOCCs were removed during treatment, and it was estimated that 2–30 t of VOCCs would be removed annually from activated sludge treatment plants in Finnish kraft pulp mills using elemental chlorine free bleaching, most likely by volatilization. Dichloroacetic acid was formed in considerably higher amounts than trichloroacetic acid, and both compounds were removed effectively during treatment. The formation of all organochlorine compounds decreased considerably when non-chlorinated bleaching was employed.

The effect of ECF and TCF bleaching on the surface chemical composition of kraft pulp as determined by ESCA

Softwood pulp samples, containing polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxins) were treated with chlorine dioxide and analyzed, before and after treatment, for the contents of dioxins. Two separate experiments were carved out under identical bleaching conditions - similar to the elemental chlorine free bleaching of kraft pulp. Each of the two experiments were duplicated, including the analytical determination of the dioxin concentrations. In the first experiments the amount of dioxins in the chlorine dioxide treated pulp was found to be between 39 and 69% of the values found in the original pulp. In the second experiments both the pulp as well as the effluents were analyzed. The results from these duplications proved to be consistent. For 2378-TCDD and 2378-TCDF, 56–63 were found in the pulp sample after chlorine dioxide treatment. The vast majority was found in the pulp while the contribution from the aqueous discharges was negligible. The conclusion is that the levels of the dioxins in the original pulp decreased as a result of the treatment of the pulp with chlorine dioxide. The results are significant since the results of the experiments, including the analytical deternrinations, were highly reproducible.

This study investigates factors affecting reproduction in fish exposed to pulp and paper mill effluents by comparing effluents from countries with varying levels of documented effects. To explore the hypothesis of wood as a common source of endocrine disrupting compounds, feedstocks from each country were analyzed. Analyses included in vitro assays for androgenic activity (binding to goldfish testis androgen receptors), estrogenic activity (yeast estrogen screen), and neurotransmitter enzyme inhibition (monoamine oxidase and glutamic acid decarboxylase). Chemical analyses included conventional extractives, known androgens, and gas chromatograph index (GCI) profiles. All effluents and wood contained androgenic activity, particularly in nonpolar fractions, although known androgens were undetected. Effluents with low suspended solids, having undergone conventional biotreatment had lower androgenic activities. Estrogenic activity was only associated with Brazilian effluents and undetected in wood. All effluents and wood inhibited neurotransmitter enzymes, predominantly in polar fractions. Kraft elemental chlorine free mills were associated with the greatest neurotransmitter inhibition. Effluent and wood GCI profiles were correlated with androgenic activity and neurotransmitter enzyme inhibition. Differences in feedstock bioactivities were not reflected in effluents, implying mill factors mitigate bioactive wood components. No differences in bioactivities could be discerned on the basis of country of origin, thus we predict effluents in regions lacking monitoring would affect fish reproduction and therefore recommend implementing such programs.

The paper and pulp industry manufactures pulp and paper from wood or recycled fiber. This chapter identifies the chemicals involved in the process of production and provides general guidance on hazardous waste mitigation. This industry is the largest industrial process water user in the United States. Its manufacturing activities result in the release of many toxic substances into the surrounding communities that pollute air, water, and land, mainly in the pulping and bleaching stages. The process of pulping consists of initial processing, washing, and bleaching. Pulping is classified as chemical, mechanical, or semi-chemical, and of the chemical pulping methods, the kraft and sulfite processes are the most widely used. Bleaching is accomplished through elemental chlorine, elemental chlorine free, or totally chlorine free bleaching. The waste stream from bleaching contains chlorine compounds and organics that result in the formation of dioxins, furans, and chlorinated organics. This waste stream of toxic air and water pollutants does not get treated at water treatment plants, accumulating in the discharge body of water. The paper and pulp sector is subject to the same environmental regulations as other industry sectors, but the most significant recent rule-making activities affecting the pulp and paper sector are referred to collectively as the Cluster Rules, a set of air and water rules that were issued simultaneously.

Modified fibres with high-cellulose content were obtained with two new bacterial xylanases from families 11 and 5. These xylanases were applied separately or simultaneously in a complete ECF (Elemental Chlorine Free) bleaching sequence. Both xylanases improved delignification and bleaching during the sequence and a synergistic effect of the enzymes was observed on several pulp and paper properties. The xylanases boosted the release of xylooligosaccharides branched with hexenuronic acids (HexA), giving rise to fibres with a reduced HexA and xylose content. However, these effects depended on the xylanase used, being the family 11 enzyme more efficient than the family 5 xylanase. Effluent properties such as absorbance spectra UV/Vis, COD and colour were affected by the enzymatic sequences as a consequence of the dissolution of lignin and xylooligosaccharides. Some changes in the fibre morphology were also produced without affecting the final paper strength properties.

The fate of lipophilic extractives from several nonwoody species (flax, hemp, sisal and abaca) used for the manufacturing of cellulose pulps, was studied during soda/anthraquinone (AQ) pulping and totally chorine free (TCF) and elemental chlorine free (ECF) bleaching. With this purpose, the lipophilic extracts from the raw materials and their unbleached and bleached industrial pulps, were analyzed by gas chromatography– mass spectrometry. Aldehydes, hydroxyfatty acids and esterified compounds such as ester waxes, sterol esters and alkylferulates strongly decreased after soda/AQ pulping while alkanes, alcohols, free sterols and sterol glycosides survived the cooking process. Among the lipophilic extractives that remained in the unbleached pulps, some amounts of free sterols were still present in the TCF pulps whereas they were practically absent in the ECF pulps. Sterol glycosides were also removed after both TCF and ECF bleaching. By contrast, saturated fatty acids, fatty alcohols and alkanes were still present in both bleached pulps.

The impacts of pulp mill effluents on white sucker (Catostomus commersoni) have been studied at Jackfish Bay, ON, Canada since the late 1980s. The site receives effluent from a large bleached kraft pulp mill which is the only source of chemical contamination in the area. Many laboratory studies have looked at the toxicological consequences of pulping process changes, but the benefit of these changes have not been looked at in wild fish. Jackfish Bay white sucker showed impacts on sexual maturity, gonad size, secondary sexual characteristics and circulating steroids hormone levels in the early years of the studies, and impacts were evaluated after installation of secondary treatment (1989), major pulping process changes (1995) and after the mill ceased pulp production and effluent release (2006). The addition of secondary treatment resulted in minor improvements in wild fish health, and the conversion to elemental chlorine free (ECF) bleaching at the mill was associated with more recovery in liver and gonad size. While some impacts persist at the exposure site, reproductive parameters showed further improvement during the mill shutdown period demonstrating that biologically active chemicals are still being discharged from modernized mills.

This paper presents the effect of the structure of cationic polyacrylamides (CPAMs) on flocculation of pulp suspensions and floc properties. A focused beam reflectance measurement (FBRM) probe was used to monitor flocculation, deflocculation, and reflocculation processes in real time. To carry out the study, 1% elemental chlorine free (ECF) eucalyptus kraft pulp containing 20% ground calcium carbonate (GCC) was used. Results show that the effect of the CPAM structure depends on charge density and polymer dose. Floc size does not always decrease with branching degree, whereas floc stability and reflocculation ability increased when highly charged and branched CPAM was used. These findings indicate that the use of highly branched CPAMs with very high molecular weight is very promising as a retention aid method to improve the papermaking process.

This study presents new and improved semi-empirical mathematical models for all the chlorine dioxide stages and extraction stages (including oxygen and/or peroxide reinforced) incorporated in a full Elemental Chlorine Free (ECF) bleaching sequence simulator developed in EFPG. The simulator predicts variations of Kappa number, pH, brightness, bleaching chemical consumption and COD at each step of multistage ECF bleaching sequences. The first purpose of this work was to improve kinetic and stoichiometric equations, involved in the chlorine dioxide stages (Do, D1, D2), for their predictability for different kinds of softwood and hardwood pulps. The second purpose was to model the extraction stages with or without oxygen and/or hydrogen peroxide reinforcement (E, EO, EOP, EP). The results predicted fit very closely to a wide range of laboratory and mill bleaching data and the predictability was extended to a greater variety of pulps (softwoods and hardwood pulps, kraft or other alkaline pulps).

Juvenile chinook salmon (Oncorhynchus tshawytscha) were exposed for 28 days to 0-16% treated effluent from an elemental chlorine free (ECF) bleached kraft pulp mill. Fresh effluent was diluted with river water drawn from upstream of the effluent diffuser. Fish were tested for biochemical responses to identify if the effluent would cause significant effects at concentrations spanning those present in the Fraser River, BC, Canada during winter conditions. Hepatic ethoxyresorufin-O-deethylase (EROD) activity was increased significantly at all effluent concentrations and hepatic cytochrome P450 1A (CYP1A) protein was increased in all but 2% effluent. Hepatic DNA adduct concentrations were increased significantly at 8 and 16% effluent. These data indicate that there is a significant increase in all three responses at concentrations similar to those found in the receiving waters (4%) and that a dose-response relationship exists between BKME concentration and the responses measured. Carcasses contained low (0.2 pg g(-1)) concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Polychlorinated biphenyls (PCBs) were at higher concentrations, accounting for 77% of the total contaminant burden, expressed as TEQ, but contaminants do not appear to have bioaccumulated in this study. It is likely that the PCB concentrations were due to contaminated commercial fish feed. Bile did not contain detectable levels of polycyclic aromatic hydrocarbons (PAHs) as measured by synchronous fluorescence spectrometry.

Nowadays, the concern on the environmental load of bleaching process gave rise to the process of ECF(elemental chlorine free) and TCF(total clorine free). These sequences are based on oxygen-derived compounds such as o xygen, ozone, and hydr ogen peroxide which is used as a typical eco -friendly bleach-ing agent.In this study, paper mulberry pulp was bleached with hydrogen peroxide and some bleaching process were accompanied with ultrasonication in order to increase the bleaching efficiency. The best bleaching efficiency of paper mulberry pulp was obtained in the conditio n of hydrogen peroxide and ultrasonication(20 kHz) bleaching system at 45 ℃ for 30 min. The brightness and kappa number of paper mulberry pulp were gained to 5.09% and 3.52 respectively. and yield was slightly loosed to 2%. Therefore, the efficiency of hydrogen peroxide and ultrasonication bleaching system of paper mulberry pulp was superior to the conventional hydrogen peroxi de bleaching system. Magnesium sulfate acted as a bleaching stabilizer for the increasement of yield. As a result, the yield and viscosity were increased to 2.2% and 12% respectively.

Dissolving pulp raw material for rayon in Indonesia is wood. The limited availability of wood, nonwood is available in large numbers such as bamboo. Bamboo fibre has long fibre. A study for making of dissolving pulp of four types of bamboo such as Apus (Gigantochloa apus), Petung (Dendrocalamus asper), Mayan (Gigantochloa robusta) and Sembilang (Dendrocalamus giganteus). The pulping process is Pre-hydrolysed-Kraft and bleaching of pulp with environmental friendly technology (Elemental Chlorine Free and enzyme). Pulp bleaching yield between 94-97% is still high. Cellulose content bamboo dissolving pulp is higher than requirements Indonesian standard specification SNI (> 94%).