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1
Madan, Sangeeta, Preeti Sachan e Utkarsh Singh. "A review on bioremediation of pulp and paper mill effluent – An alternative to conventional remedial technologies". Journal of Applied and Natural Science 10, n.º 1 (1 de março de 2018): 367–74. http://dx.doi.org/10.31018/jans.v10i1.1632.
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At present, a large amount of water required for paper production and various chemicals has been identified in effluents, which is produced at different steps of paper making in paper mills. The pulp and paper industry is typically related to pollution difficulties related to high biological oxygen demand (BOD), chemical oxygen demand (COD), colour, suspended solids, lignin and chlorinated compounds. Several studies have been made on eliminate these difficulties of pulp and paper effluents, the problem still continues. Although the physical and chemical methods are on the track of treatment, they are not on par with biological treatment because of cost ineffectiveness and residual effects. The biological treatment is known to be effective in reducing the organic load and toxic effects of paper mill effluents. Some microorganisms including bacteria and fungi have been involved in degrading the chemicals present in pulp and paper mill effluent. This article is an overview of the attempts made by several researchers worldwide to use biotechnological methods for degradation of the toxic compounds present in pulp and paper mill effluents by using fungi, bacteria, algae and enzymes. The current study clearly shows that application of native dominant bacterial and fungal isolates may be used forthe treatment of large pulp and paper mills effluents.
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Mendoza Martinez, Clara Lisseth, Ekaterina Sermyagina e Esa Vakkilainen. "Hydrothermal Carbonization of Chemical and Biological Pulp Mill Sludges". Energies 14, n.º 18 (10 de setembro de 2021): 5693. http://dx.doi.org/10.3390/en14185693.
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A modern pulp mill generates a variety of different by-products and waste streams, some of these can be recycled, refined, sold, or used on-site for energy production. However, some, such as chemical and biological sludges produced in wastewater treatment cannot be reused or disposed of easily, mainly due to their high moisture content and poor drying characteristics. Tightening legislation regarding waste disposal as well as the growing need to increase the process efficiencies of pulp mills act as driving forces to find environmentally friendly and energy-efficient techniques for pulp mill sludge treatment. This study summarizes the current methods for pulp mill sludge handling and evaluates the potential of hydrothermal carbonization (HTC), a conversion process through which wet organic substrates can be transformed into a carbonaceous material (hydrochar). Depending on the process parameters, the material’s structure is modified, enabling hydrochar use in energy, soil conditioning and adsorption applications. The sludges were hydrothermally carbonized at 180, 200, 220 and 240 °C for 3 h. The hydrochar and liquid products’ main properties were analyzed. Their potential applications were also evaluated. The effective treatment of sludges from the pulp industry with HTC could transform energy-demanding waste into a value-added source of materials.
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Kenefick, S. L., B. G. Brownlee, T. R. Perley e S. E. Hrudey. "A chemical and sensory study of odour compounds in the Athabasca River, Alberta, Canada". Water Science and Technology 31, n.º 11 (1 de junho de 1995): 15–21. http://dx.doi.org/10.2166/wst.1995.0390.
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As of early 1993, the Athabasca River received effluent from one bleached kraft pulp mill (Mill A), three chemithermomechanical pulp and paper mills, one oil sands extraction and upgrading plant and a number of municipal effluents. In the latter half of 1993 a second bleached kraft pulp mill (Mill B) began operation midway along the river. An investigation was carried out to characterize the odours in the river water using both chemical and sensory methods, in a pre- and post-operational study of the second bleached kraft mill. Both surveys were carried out under ice during low flow conditions. Samples were analysed by gas chromatography-mass spectrometry after extraction using a closed-loop stripping apparatus (CLSA). In addition, sensory analysis by flavour profile panel and olfactory gas chromatography of the CLSA extracts were performed. In 1993 all analytical methods confirmed that compounds characteristic of bleached kraft mill effluent were detectable for more than 950 km downstream from Mill A and that this effluent was the major source of odour to the Athabasca River. Chemical and sensory results for 1994 samples (collected after Mill B began operation) indicated a decrease in the impact of Mill A compared with the 1993 survey. The Mill B effluent had distinctive odour but its impact on the river was difficult to detect due to dilution and background odour from the Mill A effluent.
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HART, PETER W. "The chemical versus energy cost tug of war: A pulp mill perspective". July 2011 10, n.º 7 (1 de agosto de 2011): 37–42. http://dx.doi.org/10.32964/tj10.7.37.
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As the cost of energy and processing chemicals changes, the optimal, lowest cost operating conditions within a pulp mill also change. Additionally, the optimal cost operating point within one area of the mill may not result in a total mill low cost operation. Three practical pulp mill examples have been analyzed under varying cost constraints for energy and chemicals to determine the impact of energy and chemical cost changes on the low cost operating point. These examples include changing the digester kappa number target, changing the brownstock washing dilution factor, and the conversion of a continuous digester from one type of cooking process to a lower energy cooking process. Selected mill operating results and laboratory data were employed to tune various process simulation models to obtain cost predictions over a wide range of operating conditions.
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Panneerselvam, L. "Water Pollution Abatement in Small Paper Mills in India". Water Science and Technology 20, n.º 1 (1 de janeiro de 1988): 37–48. http://dx.doi.org/10.2166/wst.1988.0006.
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In order to reduce the demand for the forest based raw materials by the organised industrial sectors like the large integrated pulp and paper mills, the Government of India started promoting several small-scale pulp and paper mills based on non-wood agricultural residue raw materials. However promotion of these small mills has created another environmental problem i.e. severe water pollution due to non-recovery of chemicals. Because of the typical characteristics like high silica content etc. of the black liquor produced and the subsequent high capital investment needed for a recovery system, it is not economically feasible for the small Indian mills to recover the chemicals. While the quantity of wastewater generated per tonne of paper produced by a small mill is same as from a large integrated pulp and paper mill with a chemical recovery system, their BOD load is four times higher, due to non recovery of chemicals. However the existing wastewater disposal standards are uniform for large and small mills for e.g. 30 mg BOD/l. To meet these standards, the small mills have to install a capital intensive wastewater treatment plant with heavy recurring operating costs. Therefore the feasible alternative is to implement various pollution abatement measures, with the objective of not only reducing the fibre/chemical loss but also to reduce the investment and operating costs of the final wastewater treatment system. To illustrate this approach, a case study on water pollution abatement and control in a 10 TPD mill, will be discussed.
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ALLEN, LAWRENCE H., e ALAIN GAGNÉ. "Effects of Acetone Extractives in Gray-Stage Lodgepole Pine Killed by Mountain Pine Beetles". February 2011 10, n.º 2 (1 de março de 2011): 47–54. http://dx.doi.org/10.32964/tj10.2.47.
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The mountain pine beetle epidemic in British Columbia is leaving behind vast stands of dead pine trees to be harvested. Several years after death, when the needles have fallen off, the trees are referred to as gray-stage. The trees’ natural defense system when attacked is to pitch out the beetles by producing large amounts of canal resin to flood the beetles’ bore holes; hence, changes in wood resin (extractives) will accompany beetle attack. Increased extractives concentration has been shown in the final bleached pulp in a kraft mill pulping a large proportion of gray-stage pine wood killed by the mountain pine beetle. Similar to the wood extractives content in gray-stage pine chips, pulp extractives in gray-stage mill pulps are variable and can occasionally be high (e.g., > 0.05%), likely because of the composition of the extractives in the incoming chips. Although this usually does not cause pitch problems in the pulp mill and its customer paper mills, kraft mills that sell gray-stage pulp to extractives-sensitive customers should check extractives content before shipment to make sure it is not unacceptably high.
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Hu, Thomas Q., Michelle Zhao, Paul Bicho e Pierre Losier. "A method for estimating wood chip brightness and its applications1This article is a contribution to the series The Role of Sensors in the New Forest Products Industry and Bioeconomy." Canadian Journal of Forest Research 41, n.º 11 (novembro de 2011): 2114–19. http://dx.doi.org/10.1139/x11-059.
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Methods for estimating wood chip brightness are important in classifying wood chips in chip piles, stabilizing chip brightness in the pulping process, and reducing bleaching chemical consumption in pulp mills. They also allow us to understand and control factors including outdoor storage in the summer that affect chip and pulp brightness. An accurate off-line method for estimating wood chip brightness has been developed. The method involves a two-stage grinding of air-dried wood chips to powders with small particle sizes and narrow size distributions and measurement of ISO (International Standardization Organization) brightness of the resulting powders. Using this method, ISO brightness values of 20 mill or pilot-plant thermomechanical pulps (TMP) can be linearly correlated, with an r2 value of 0.885, with ISO brightness of the mill or pilot-plant wood chips. Analyses of wood chips and TMP samples taken from a TMP mill every month for 1 year show that both the chip and TMP brightness values are the lowest in July. The method can be used for laboratory analysis of chip brightness, monitoring of chip brightness monthly variation in pulp mills, and checking the accuracy of the on-line chip brightness measurement system.
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Vargas, R., J. R. Sanjuán D., J. A. Silva G., J. Rivera P., F. J. Fuentes T. e H. G. Richter. "Properties of bleached pulp sheets of avocado wood (Persea americana Mill.) pulped by Kraft and Soda processes". Madera y Bosques 12, n.º 1 (31 de agosto de 2016): 29–36. http://dx.doi.org/10.21829/myb.2006.1211248.
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Chips of avocado wood (Persea americana Mill.) were pulped by means of conventional Soda and Kraft pulping processes. The pulps were bleached with an elemental-chlorine-free sequence OD1-Eop-D2, pre-setting reaction conditions for the first chlorine dioxide stage (D1) . The results show that during the chemical pulping process, avocado wood is easier to cook than other hardwoods such as eucalyptus. The avocado pulp also showed a very good bleachability, reaching brightness levels of up to 92% ISO compared to 84% for eucalyptus after the ECF bleaching sequence. The avocado Kraft pulps required more chemical input in the bleaching sequence than the Soda pulps. On the other hand, the physico-mechanical properties of the pulp were not notably reduced by the bleaching process, the Kraft pulp being stronger than the soda pulp. Strength properties of avocado are similar to those of eucalyptus; therefore this raw material constitutes a worthwhile choice for cellulosic fiber supply.
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KORPUNEN, HEIKKI, PEKKA VIRTANEN, OLLI DAHL, PAULA JYLHÄ e JORI UUSITALO. "An activity-based cost calculation for a kraft pulp mill". September 2012 11, n.º 9 (1 de outubro de 2012): 19–27. http://dx.doi.org/10.32964/tj11.9.19.
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This study introduces an activity-based costing (ABC) method for a kraft pulp mill. Our ABC model defines the production resources and costs for each process in a chemical pulp mill and allocates the costs to pulp, energy, bark, turpentine, and crude tall oil. The production processes include receiving, unloading and debarking of pulpwood, chipping, chip screening, chip storing, cooking and in-digester washing, pulp washing and screening, oxygen delignification, bleaching, drying, and chemical recovery. We also tested the effect of Scots pine pulpwood properties on the profitability of a virtual greenfield pulp mill located in Finland, where it produced 600000 air-dried (a.d.) metric tons of bleached market pulp annually. Total annual production costs were approximately EUR 216 million (USD 285 million), of which chemical recovery comprised the biggest share (almost 39%). According to the results, the price of market pulp had the most significant effect on the profitability of the mill. The pulpwood properties did not clearly affect pulp production costs; the wood procurement costs had more influence on the profitability of the value chain. Our results also indicate that the profitability of pulp making is strongly dependent on the prices of electricity and heat. This is because the mill is customer and seller in energy markets. ABC proved to be a useful tool and accurate method for cost calculation in this highly competitive branch of the forest industry.
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JACOBY, MITCH. "CATALYTIC CLEANUP AT THE PULP MILL". Chemical & Engineering News 80, n.º 12 (25 de março de 2002): 39–40. http://dx.doi.org/10.1021/cen-v080n012.p039.
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Lapierre, Luc, Jean Bouchard e Richard Berry. "On the relationship between fibre length, cellulose chain length and pulp viscosity of a softwood sulfite pulp". Holzforschung 60, n.º 4 (1 de julho de 2006): 372–77. http://dx.doi.org/10.1515/hf.2006.058.
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Abstract Many chemical pulp mills use pulp viscosity as an indicator of pulp strength, and some mill customers stipulate a particular viscosity threshold for the delivered product. Nevertheless, the value of the viscosity-strength relationship is often questioned, particularly as it varies with the wood species and the pulping process. To provide some insight, the viscosity, degree of polymerisation and fibre length were measured for a bleached softwood sulfite pulp segregated into different fractions with respect to fibre length using a Bauer-McNett fractionator. It was demonstrated that fractions with a longer average fibre length also had a higher degree of polymerisation and higher viscosity. The cellulose chain length in chemical pulps is approximately three orders of magnitude shorter than the fibre length, and thus a relationship between these two properties should not be expected. The possible causes of the correlation between fibre length and viscosity are discussed. In this work, viscosity appears to be an indirect measurement of the average fibre length of a pulp, which would be the direct contributor to the strength of that pulp.
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Saunamäki, R. "Activated sludge plants in Finland". Water Science and Technology 35, n.º 2-3 (1 de fevereiro de 1997): 235–43. http://dx.doi.org/10.2166/wst.1997.0527.
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The performance of Finnish activated sludge plants (primary clarifier, equalization basin, buffer basin, aeration basin, secondary clarifier and sludge handling) was surveyed. Performance was generally found to be excellent. BOD7 removal averaged 94% at paper mills (21mg/l effluent concentration, 0.43 kg/t discharge) and 95% at chemical pulp mills (18 mg/l, 0.83 kg/t). CODCr removal averaged 82% at paper mills (158 mg/l effluent concentration, 3.52 kg/t discharge) and 60% at pulp mills (531 mg/l, 20.7 kg/t). Treated effluent from paper mills contained 0.57 mg/l (13.3 g/t) of total phosphorus and from pulp mills 1.31 mg/l (47.3 g/t). AOX removal was 45-65% and discharge 0.15-0.90 kg/t. Suspended solids removal averaged 91% at paper mills and 76% at pulp mills, the average overflow concentration in primary clarifier being about 150 mg/l at both types of mill. All activated sludge plants are designed according to either the low load or extended aeration principle; high load plants are no longer in use. The average sludge load was 0.15 kg BOD/(kg MLSS d), the sludge age at the extended aeration plants ranging from 20 to 50 d. Low load appearance to be the main reason for the good performance of the plants. Other factors included the introduction of equalization and buffer basins at many plants, and particularly the fact that aeration factors and nutrients were under control. All paper mill activated sludge plants use nitrogen and phosphorus additions, whereas pulp mill plants manage without phosphorus. Optimization of nutrient addition is vital because almost every mill in Finland has a limit for its phosphorus discharge. Total sludge production at the paper mill plants averaged 40.9 t/d, 15% of which (5.9 t/d, 6.0 kg/t) was biosludge. At the pulp mills the figures were 27.2 t/d (11.5 t/d biosludge, 9.5 kg/tp). Belt filter presses are used for dewatering at most plants and dry solids contents are usually 25-35%. New-generation screw presses have been introduced, mainly at new pulp mill activated sludge plants, yielding dry solids contents of 40%. Combined and dewatered sludge is normally burned in bark-fired boilers, although some mills still landfill their sludge.
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HOVIKORPI, KIRSI, e ESA VAKKILAINEN. "Sources, collection, and handling of noncondensible gases in modern kraft pulp mills". TAPPI Journal 18, n.º 5 (1 de junho de 2019): 297–305. http://dx.doi.org/10.32964/tj18.5.297.
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This work describes and discusses sources of noncondensible gases (NCG) in modern kraft pulp mills and modern NCG collection from process units where odor emissions can occur if these gases are released to the surroundings. A mill-wide overview of NCG sources and collection in modern pulp mills is provided. Using modern practices, malodorous gases can be collected to the extent that a pulp mill is essentially odor free. The key to limiting complaint-causing odors is prevention of these emissions during process disturbances, equipment malfunctions, operator errors, and other unforeseen occurrences.
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Kumar, Virendra, Purnima Dhall, Rita Kumar, Yogendra Prakash Singh e Anil Kumar. "Bioremediation of Agro-Based Pulp Mill Effluent by Microbial Consortium Comprising Autochthonous Bacteria". Scientific World Journal 2012 (2012): 1–7. http://dx.doi.org/10.1100/2012/127014.
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Small-scale agro-based pulp and paper mills are characterized as highly polluting industries. These mills use Kraft pulping process for paper manufacturing due to which toxic lignified chemicals are released into the environment. Lack of infrastructure, technical manpower, and research and development facilities restricts these mills to recover these chemicals. Therefore, the chemical oxygen demand (COD) of the emanating stream is quite high. For solving the above problem, four bacteria were isolated from the premises of agro-based pulp and paper mill which were identified as species ofPseudomonas, Bacillus, Pannonibacter, andOchrobacterum. These bacteria were found capable of reducing COD up to 85%–86.5% in case of back water and 65-66% in case of back water : black liquor (60 : 40), respectively, after acclimatization under optimized conditions (pH 6.8, temperature 35°C, and shaking 200 rpm) when the wastewater was supplemented with nitrogen and phosphorus as trace elements.
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Kihlman, Jonas, e Christer Gustavsson. "The feasibility of utilizing existing process streams in kraft pulp mills as a source of chemicals for lignin extraction". BioResources 16, n.º 1 (16 de dezembro de 2020): 1009–28. http://dx.doi.org/10.15376/biores.16.1.1009-1028.
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Lignin is a sustainable raw material with a high potential for use in the production of renewable products. While the market for lignin is slowly growing, lignin recovery via acid precipitation during the kraft pulping process requires the addition of chemicals that will impact the chemical balance of the pulp mill. This negatively affects both the environmental and business operations. Utilizing existing process streams as a source of chemicals will allow the mill to close the chemical loop and reduce emissions, which will have positive environmental impacts. This study investigated the internal production of sulphuric acid (H2SO4) and carbon dioxide (CO2) for use in lignin separation (also called extraction) at a Swedish kraft pulp mill. The process simulation tool CHEMCAD was used to model and analyze the wet gas H2SO4 (WSA) process to produce H2SO4. The chemical absorption process using monoethanolamine (MEA) to capturing CO2 was also analyzed. The utilization of the sulphur-containing gases to produce H2SO4 can generate an amount that corresponds to a significant lignin extraction rate. The CO2 available in the flue gases from a mill well exceeds the amount required for lignin extraction.
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BROWN, RON. "Agenda 2020: Next Generation Chemical Pulping",. October 2014 13, n.º 10 (1 de novembro de 2014): 10–11. http://dx.doi.org/10.32964/tj13.10.10.
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OBJECTIVE: Develop next-generation chemical pulping processes that preserve fiber strength and pulp performance attributes while achieving one or more of the following: 1) Reduce total input energy by 25% 2) Increase yield of fiber by 5% based on wood (e.g., from 50% to 55%) 3) Reduce BOD/COD effluents by 25% 4) Reduce capital intensity of a new pulp mill by 25%
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Huber, L., e H. Baumung. "Requirements for the Treatment of Effluents from Chemical Pulp Mills in the F.R.G." Water Science and Technology 20, n.º 1 (1 de janeiro de 1988): 19–24. http://dx.doi.org/10.2166/wst.1988.0004.
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In 1986, the 11 chemical pulp mills in the F.R.G. produced 350,00 t of bleached sulfite pulp. With the enactment of the so-called minimum requirements in 1982, general standards for the treatment of effluents were promulgated for this branch of industry. They comprise various measures, such as high-grade recovery of spent liquor including its evaporation and incineration, partial or total reuse of condensates from evaporation or reduction of their load by stripping, and mechanical treatment of total waste water. In view of the persisting high pollution levels of German rivers caused by pulp mills, more stringent standards reflecting the present state of the art will be implemented in 1991. This paper deals with these standards, covering the applicable in-plant and external abatement measures, such as extended cooking, substitution of elemental chlorine and biological treatment for decisive improvement of the chemical pulp mill effluent situation.
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KANGAS, PETTERI. "Screening the new process concepts for pulp mill retrofits with varying capacity constraints". April 2016 15, n.º 4 (1 de maio de 2016): 241–50. http://dx.doi.org/10.32964/tj15.4.241.
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A new methodology for screening the potential of new pulp mill concepts as part of retrofits is presented. A generic method for describing different capacity constraints or bottlenecks is given. These constraints are considered in order to illustrate the potential of new concepts applied in different kinds of pulp mills. The presented methodology combines the generality of theoretical reference mills and the specific details of case studies. Results of the study show that the feasibility of different process concepts heavily depends on the limiting factors of a pulp mill. The methodology is a possible tool for scholars and experts to illustrate where new process concepts should be implemented.
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Klugman, Sofia, Magnus Karlsson e Bahram Moshfegh. "A Scandinavian chemical wood-pulp mill. Part 2. International and model mills comparison". Applied Energy 84, n.º 3 (março de 2007): 340–50. http://dx.doi.org/10.1016/j.apenergy.2006.07.004.
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MATEOS-ESPEJEL, ENRIQUE, THEODORE RADIOTIS e NACEUR JEMAA. "Implications of converting a kraft pulp mill to a dissolving pulp operation with a hemicellulose extraction stage". TAPPI Journal 12, n.º 2 (1 de março de 2013): 29–38. http://dx.doi.org/10.32964/tj12.2.29.
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Global demand for dissolving pulp has been increasing at a remarkable pace over the last few years. A shortage in cotton and the expansion of the textile, hygiene, and health product markets are behind this booming demand. The Canadian pulp and paper industry has entered these markets by converting several paper-grade pulp mills to dissolving pulp producers. In the kraft process, part of the hemicellulose remains with the pulp after cooking and the rest is burnt in the recovery boiler to produce energy. In dissolving pulp mills, most of the hemicellulose must be removed from the wood chips in a pre-hydrolysis stage before pulping. Hemicellulose hydrolysis and its subsequent extraction will affect energy and chemical balances. In addition, the new operation will require large capital expenditures. The objective of this work was to study the conversion of a kraft pulp mill to a dissolving pulp operation and the extraction of hemicelluloses from the process. The effects of hemicellulose extraction on mill energy balance, equipment requirements, and new operating conditions were analyzed. Computer simulations of the process and thermal pinch analysis were used. The existing bottlenecks (digesters, lime kiln, and recovery boiler) to increasing the dissolving pulp production capacity were identified before and after the conversion. In addition, energy efficiency measures were identified to decrease the energy consumption of the new process.
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ANDREWS, JOHN D., e PETER W. HART. "Improving pulp yield for integrated southern hardwood kraft mills—significance and impact on chemical recovery, steam and power generation, and bleaching". TAPPI Journal 12, n.º 2 (1 de março de 2013): 41–53. http://dx.doi.org/10.32964/tj12.2.41.
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Researchers have been attempting to improve the yield of bleachable-grade kraft pulp for several decades. Wood is typically one of the major costs associated with kraft pulping. Therefore, it is typically assumed that improving pulp yield or conversely, reducing the amount of wood required to make a specific mass of pulp, is a cost-effective, lucrative endeavor. Although this may be true, it is important to understand the impact of increasing pulp yield on the interconnected processes within an integrated pulp and paper mill and to fully evaluate the cost implications on these processes. The current work employed several sets of laboratory pulping conditions and a WinGEMS model of a pulp mill, fully integrated with chemical recovery, power, and recausticization, and pulp drying islands to determine where the largest cost impact associated with improved pulp yield may be experienced.
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Sarlin, T., S. Halttunen, P. Vuoriranta e J. Puhakka. "Effects of Chemical Spills on Activated Sludge Treatment Performance in Pulp and Paper Mills". Water Science and Technology 40, n.º 11-12 (1 de dezembro de 1999): 319–25. http://dx.doi.org/10.2166/wst.1999.0728.
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The aim of this research was to study the effects of chemical spills on activated sludge metabolic activity and settleability. On-site, laboratory-scale tests were carried out at three pulp and paper mill activated sludge plants. Oxygen uptake rate (OUR) and dissolved organic carbon (DOC) removal were used for monitoring of metabolic inhibition. The effects of chemicals on 30-min settled sludge volume were studied. Accidental release reports from five pulp and paper mills were analysed. Thirty-four chemicals were selected to the laboratory tests. Of the tested chemicals 2 biocides, monochloro acetic acid, soft soap and turpentine inhibited the OUR of the sludge and thus, had an acute toxic effect on the activated sludge. The biocides and disperging agent reduced DOC removal. Aluminium sulphate and optical brightener had a negative effect on sludge settleability and thus, they may cause losses of activated sludge from treatment plant. In conclusion, maximum possible spill of the five chemicals may reduce the performance of the activated sludge.
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Lundqvist, Sven-Olof, e Egils Kubulnieks. "Improved Production and Product Information for Chemical Pulp Mill Operators". IFAC Proceedings Volumes 28, n.º 21 (setembro de 1995): 19–24. http://dx.doi.org/10.1016/s1474-6670(17)46694-8.
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Vidal, Gladys, Yenifer González, Benjamín Piña, Mayra Jarpa e Gloria Gómez. "Minimization of Environmental Impact of Kraft Pulp Mill Effluents: Current Practices and Future Perspectives towards Sustainability". Sustainability 13, n.º 16 (18 de agosto de 2021): 9288. http://dx.doi.org/10.3390/su13169288.
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Kraft mill effluents are characterized by their content of suspended solids, organic matter and color due to the presence of lignin, lignin derivatives and tannins. Additionally, Kraft mill effluents contain adsorbable organic halogens and wood extractive compounds (resin acids, fatty acids, phytosterol) and show high conductivity due to the chemical compounds used in the digestion process of pulp. Currently, Kraft mills are operating under the concept of a linear economy and, therefore, their effluents are generating serious toxicity effects, detected in daphnia, fish and biosensors. These effluents are treated by activated sludge and moving bed biofilm systems that are unable to remove recalcitrant organic matter, color and biological activity (toxicity) from effluents. Moreover, under climate change, these environmental effects are being exacerbated and some mills have had to stop their operation when the flows of aquatic ecosystems are lower. The aim of this review is to discuss the treatment of Kraft pulp mill effluents and their impact regarding the current practices and future perspectives towards sustainability under climate change. Kraft pulp mill sustainability involves the closure of water circuits in order to recirculate water and reduce the environmental impact, as well as the implementation of advanced technology for these purposes.
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Patterson, S. L., D. S. Chanasyk, M. A. Naeth e E. Mapfumo. "Effect of municipal and pulp mill effluents on the chemical properties and nutrient status of a coarse-textured Brunisol in a growth chamber". Canadian Journal of Soil Science 88, n.º 3 (2 de maio de 2008): 429–41. http://dx.doi.org/10.4141/cjss07039.
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Maximizing productive use and minimizing the environmental impacts of effluents require research on application rates. This study evaluated the effect of effluents from a Kraft pulp mill [a final effluent (KPME) and a waste activated sludge (WAS)], a municipality (ME) and tap water (TPW) applied at rates of 1.5, 3 and 6 mm d-1 on reed canarygrass (Phalaris arundinacea L. cv. Vantage) and hybrid poplar (Populus deltoides × P. petrowskyana var. Walker). The two pulp mill effluents significantly increased soluble soil SO4, Na and Cl. Soil solution electrical conductivity (EC) and sodium adsorption ratio (SAR) increased with pulp mill effluents compared with ME and TPW. Soil solution SAR increased from less than 1 to a range of 2.7 to 4.0 for the municipal effluent and 8.4 to 14.0 for the two pulp mill effluents. Soil solution EC increased from 1.1 to 2.3 dS m-1 to a range of 1.8 to 3.4 dS m-1 for municipal effluent and 5.1 to 6.1 dS m-1 as a result of pulp mill effluent applications. Under reed canarygrass, soils had lower concentrations of cations and anions than those under hybrid poplar, suggesting crop uptake and leaching. Thus, salt loadings of soils must be considered when determining application rates of effluents for irrigation. Key words: Electrical conductivity, hybrid poplar, effluent irrigation, sodium adsorption ratio
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Aguayo, María Graciela, Regis Teixeira Mendonça, Paulina Martínez, Jaime Rodríguez e Miguel Pereira. "Chemical characteristics and Kraft pulping of tension wood from Eucalyptus globulus labill". Revista Árvore 36, n.º 6 (dezembro de 2012): 1163–72. http://dx.doi.org/10.1590/s0100-67622012000600017.
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Tension (TW) and opposite wood (OW) of Eucalyptus globulus trees were analyzed for its chemical characteristics and Kraft pulp production. Lignin content was 16% lower and contained 32% more syringyl units in TW than in OW. The increase in syringyl units favoured the formation of β-O-4 bonds that was also higher in TW than in OW (84% vs. 64%, respectively). The effect of these wood features was evaluated in the production of Kraft pulps from both types of wood. At kappa number 16, Kraft pulps obtained from TW demanded less active alkali in delignification and presented slightly higher or similar pulp yield than pulps made with OW. Fiber length, coarseness and intrinsic viscosity were also higher in tension than in opposite pulps. When pulps where refined to 30°SR, TW pulps needed 18% more revolutions in the PFI mill to achieve the same beating degree than OW pulps. Strength properties (tensile, tear and burst indexes) were slightly higher or similar in tension as compared with opposite wood pulps. After an OD0(EO)D1 bleaching sequence, both pulps achieved up to 89% ISO brightness. Bleached pulps from TW presented higher viscosity and low amount of hexenuronic acids than pulps from OW. Results showed that TW presented high xylans and low lignin content that caused a decrease in alkali consumption, increase pulp strength properties and similar bleaching performance as compared with pulps from OW.
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Borges, Maria Tereza, Claudio Mudado Silva, Jorge Luiz Colodette, Rubens Chaves de Oliveira e Flavio Tesser. "Enzymatic bleaching of eucalyptus kraft pulp: effects on the prebleaching filtrate, pulp quality and paper properties". Holzforschung 67, n.º 2 (1 de fevereiro de 2013): 147–53. http://dx.doi.org/10.1515/hf-2011-0130.
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Abstract Enzymatic bleaching appears to be a promising approach for clean bleaching processes and the reduction of bleaching chemical consumption. In this work, the quality of the filtrates and the pulps has been characterized after enzymatic prebleaching stages of eucalyptus kraft pulp. Four different conditions with xylanase were investigated. Following each prebleaching stage, the properties of the pulp [kappa number, brightness, content of hexenuronic acid (HexA), xylan removal, and pulp yield lost], and of the resulting effluents (chemical oxygen demand (COD), biochemical oxygen demand (BOD), color, and conductivity) were determined. In addition, a complete bleaching sequence was performed to characterize the pulp quality at the end of the sequence. Finally, the pulp was refined in a PFI mill, and the mechanical and physical properties of the resulting paper were determined. The best pulp quality was achieved at pH 7, at which a lower kappa number, higher pulp brightness, and smaller amount of HexA were observed. Under this condition, however, a larger yield loss and a higher effluent COD load had to be accepted. After the complete bleaching sequence, the enzymatic treatments yielded pulps with higher brightness and viscosity as well as with a lower kappa number. The enzymatic treatments resulted in small changes in the mechanical and physical properties of the paper handsheets produced.
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Wang, Hailong, G. N. Magesan, Mark O. Kimberley, Gerty J. H. P. Gielen e Stephen H. Pearce. "Chemical properties of two soils irrigated with thermo-mechanical pulp mill effluent". Soil Research 43, n.º 8 (2005): 929. http://dx.doi.org/10.1071/sr05052.
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The effect of land application of thermo-mechanical pulp (TMP) mill effluent on soil chemical properties was examined using barrel lysimeters. Twelve lysimeters, 500 mm in diameter and 800 mm high, containing either a volcanic soil (Udivitrand) or a pallic soil (Haplustalfs), were collected from 2 plantation forest sites. A TMP mill effluent containing high concentrations of total organic C (1136 mg/L) was irrigated at 30 mm/week over a period of 16 months. Soil sample analysis indicated that build up of soil organic C was negligible despite large additions of organic C (equivalent to 19 t/ha) through irrigation with TMP mill effluent. Mass balance calculation implied that microbial degradation or mineralisation of the organic compounds might be the main mechanism involved in the high renovation rates. Irrigation with TMP mill effluent significantly increased soil pH, concentrations of soil total S, available P, and exchangeable K and Na, but it had no significant effect on concentrations of soil total N, and exchangeable Ca and Mg. The results from this study indicate that TMP mill effluent irrigated at a loading rate not greater than 30 mm/week would cause little detrimental effect on the quality of soils at these 2 plantation forest sites.
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HOSTACHY, JEAN-CHRISTOPHE. "Ozone-enhanced bleaching of softwood kraft pulp". August 2010 9, n.º 8 (1 de setembro de 2010): 16–23. http://dx.doi.org/10.32964/tj9.8.16.
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By using ozone in their bleaching processes, many hardwood pulp mills in various parts of the world have improved product quality and their environmental and process performance, and reduced operating costs to increase competitiveness. The challenge for softwood pulp is to rethink the use of ozone according to their specific requirements. This paper summarizes results obtained using ozone bleaching on softwood (Pinus radiata) kraft pulp, for which the brightening ability of limited ozone dosages can enhance the economic benefits without impairing pulp quality. This work evaluated the chemical justification to use ozone at the end of the bleaching sequence and the effect on pulp quality, and considered the practical consequences of this new option. Special attention was given to the economic and technical aspects, including investment cost, variable cost, and process implementation. Ozone was shown to be the ideal complement of chlorine dioxide for final pulp bleaching. Both chemicals can easily be combined at the end of the bleaching sequence. Taking into account pulp mill capacity, capital investment, and total operating cost, the financial savings were calculated to be in the range of EUR 5 million (USD 6 million) per year, with a payback period of about 1.5 years.
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Rantamäki, Jukka Mikael, e Olli Saarela. "Diagnosis and economic impact of operational variability – a case from the chemical forest industry". Journal of Quality in Maintenance Engineering 21, n.º 3 (10 de agosto de 2015): 294–309. http://dx.doi.org/10.1108/jqme-03-2014-0011.
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Purpose – This paper deals with the identification and diagnosis of operational variability in chemical processes, which is a common problem in mills but little explored in literature. The Cross-Industry Standard Process for Data Mining (CRISP-DM) is a widely used approach in problem solving. The purpose of this paper is to: first, contribute to the body of knowledge on applying CRISP-DM in a pulp mill production process and the special issues that need to be considered in this context. Exact amounts of a cost increase due to variation in pulp production have not been reported previously. Second, to quantify the cost of variation. Design/methodology/approach – In the case studied, the variation in a pulp mill batch cooking process had increased. In order to identify the causes of variation, CRISP-DM was applied. Findings – The cycle of variation was identified and found to be related to the batch cooking process cycle time. By using information from this analysis it was possible to detect otherwise unobserved defective steam nozzles. The defective equipment was repaired and improved. Further improvement was achieved when the fouling of a heat exchanger was found by analysis to be the root cause of long-term variability parameters. By applying CRISP-DM, equipment defects and fouling were identified as the root causes of the higher manufacturing costs due to increased variation were detected and estimated. The Taguchi loss function is a possible tool for estimating the cost of variation in pulp manufacturing. Originality/value – This paper provides new knowledge in the context of implementing CRISP-DM and the Taguchi loss function in the pulp and paper manufacturing process.
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RICARD, MICHELLE, e GILLES DORRIS. "Added soap contact time with recycled pulp improves flotation deinking efficiency and reduces cost". November 2014 13, n.º 11 (1 de dezembro de 2014): 27–35. http://dx.doi.org/10.32964/tj13.11.27.
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Optimization of the fatty acid soap addition points increased soap contact time with recycled pulp before flotation. This, in turn, resulted in improved ink removal efficiencies for three of four types of commercial flotation cells. Mill A saved 25% in fatty acid flotation collector dosage while maintaining the same brightness gain and ink removal efficiency. In mill B, increasing the soap contact time improved the aeration of one line of flotation cells, which in turn led to a 1-point brightness improvement of deinked pulp and savings in bleaching chemicals. Both mills showed 30%–54% lower carryover of saturated fatty acids from the flotation collector to newsprint made from deinked pulp and thermomechanical pulp. Flotation cells with longer residence times and aeration injectors in good order did not show any improvement in aeration or flotation efficiency. Soap contact times with pulp, whether before or during flotation, should be on the order of 9–20 min to assure maximal flotation efficiency. Increasing soap contact time before flotation to 45-60 min did not further improve flotation efficiency.
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Sousa, Cátia T., Dmitry V. Evtuguin e José L. Amaral. "Hardwood kraft pulp structural features affecting refinability". Holzforschung 71, n.º 7-8 (26 de julho de 2017): 619–24. http://dx.doi.org/10.1515/hf-2016-0205.
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Abstract Two industrial bleached Eucalyptus globulus kraft pulps (pulps A and B), cooked from the same wood stock with slightly different alkali charges and temperatures, showed different refinability in the laboratory beating of pulp using a PFI mill. The easy to refine pulp (A) and the difficult to refine pulp (B) did not reveal significant differences in their biometric data and general chemical composition, but pulp A showed ca. 5%–10% higher mechanical strength and twice as high refinability compared to pulp B. These differences were ascribed to slightly higher intrinsic viscosity and higher xylan content of pulp A compared to pulp B (1010 vs. 860 cm3 g−1 and 20.1 vs. 17.8%, respectively). The xylan structure and its location in fiber cells were also different, which affected the pulp’s refinability. The presence of high proportion of xylan in the bulk of fibers, rather than in their outer layers, seems to favor the pulp beating. An interpretation was also proposed, according to which the aggregation of cellulose fibrils during cooking, i.e. a partial coalescence of fibril crystallites, may also have a negative effect on pulp refinability.
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Magalhães, W. L. E., A. E. Job, C. A. Ferreira e H. D. da Silva. "Pyrolysis and combustion of pulp mill lime sludge". Journal of Analytical and Applied Pyrolysis 82, n.º 2 (julho de 2008): 298–303. http://dx.doi.org/10.1016/j.jaap.2008.05.005.
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LAPIERRE, LUC, JEAN BOUCHARD e RICHARD BERRY. "Assessment of pulp machine white water quality at market kraft pulp mills". March 2012 11, n.º 3 (1 de abril de 2012): 71–76. http://dx.doi.org/10.32964/tj11.3.71.
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The bleaching of pulp is a significant cost, yet the brightness achieved in the bleaching plant can be diminished in the pulp machine because of white water (WW) quality. Monitoring WW quality can control these losses. A method was developed to assess WW quality that allows differentiation between the effect of fibers, fines, and dissolved solids (DS) in the WW. It was found that the quality of the WW varied greatly from mill to mill. The brightness loss was mainly affected by the presence of fines, through a combination of their concentration and color. The DS were significantly less detrimental to the optical properties of the final furnish. None of the constituents present in the pulp machine WW caused significant brightness reversion (except the hardwood fine fractions). It is therefore recommended that a monitoring procedure for WW quality at the mill site be used to diagnose and prevent the occurrence of brightness problems. Such monitoring offers a way to reduce bleaching costs.
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Cabral, F., E. Vasconcelos, M. J. Goss e C. MDS Cordovil. "The value, use, and environmental impacts of pulp-mill sludge additions to forest and agricultural lands in Europe". Environmental Reviews 6, n.º 1 (1 de março de 1998): 55–64. http://dx.doi.org/10.1139/a98-004.
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The current state of knowledge on the recycling of pulp sludge in the forest and agricultural lands as an alternative to disposal is reviewed. Effects of land application of pulp sludge on chemical and physical properties of soils, on leaching of chemical constituents to groundwater, and on yields of crops are discussed. Regions in Europe where land application of pulp sludge are potentially most beneficial are identified. Information on pulp production, pulping and bleaching methods, and treatments of the effluents, as well as its environmental implications, are also briefly reviewed.Key words: Europe, Mediterranean region, pulp sludge, land application, forest and agricultural sites, environmental impacts.
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Paasivirta, J., A. L. Rantalainen, L. Welling, S. Herve e P. Heinonen. "Organochlorines as Environmental Tainting Substances: Taste Panel Study and Chemical Analyses of Incubated Mussels". Water Science and Technology 25, n.º 2 (1 de janeiro de 1992): 105–13. http://dx.doi.org/10.2166/wst.1992.0041.
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Lake mussels (Anodonta piscinalis) incubated in freshwater stations upstream and downstream of a large pulp mill were studied for tainting by a panel of 18 persons. The tasted animal muscle and tissue water samples, and composites of other simultaneously incubated mussels were analyzed for organochlorine compounds. Bad taste scores were obtained for mussels from the nearest station downstream to the pulp mill and were significantly (p < 0.001 **) higher than those from other stations. A similar difference was observed for the measured chlorophenol, chloroanisole and chloroveratrole, chlorocymene and PCB contents. Chloroanisoles and chloroveratroles were indicated to form the main tainting load in the studied mussels.
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Mehmood, Rehman, Wang, Farooq, Mahmood, Jadoon, Javed e Ahmad. "Treatment of Pulp and Paper Industrial Effluent Using Physicochemical Process for Recycling". Water 11, n.º 11 (14 de novembro de 2019): 2393. http://dx.doi.org/10.3390/w11112393.
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Physicochemical treatment, consisting of a combination of primary settling, coagulation–flocculation-aided clarification (alum, lime and magnesium sulfate as coagulants) and activated carbon adsorption, was employed for the treatment of pulp and paper mill wastewater. Treatability studies were undertaken to assess the feasibility of recycling the effluents from a paper mill. The results of laboratory scale investigation showed that the hydraulic retention time (HRT) of four hours for plain settling was effective to reduce 30% of the pollution load from pulp and board mill wastewater (PBMWW). The chemical secondary treatment reduced turbidity (89%), Chemical Oxygen Demand (84%), total suspended solids (90%) and color (89%) at the mass loading of 3400 mgl-1 of magnesium sulfate (MgSO4), when primary-treated effluent was subsequently treated by the coagulation–flocculation process. The combination of primary settling and lime coagulation (optimum dosage of 1400 mgl-1) resulted in a turbidity removal of 94%, a COD (Chemical Oxygen Demand) reduction of 86%, a Total Suspended Solids (TSS) removal of 93% and color removal of 91.6% at an initial pH of 11. The combination of this primary settling and coagulation–flocculation treatment trial indicated that the pollutant reduction efficiency of alum was better than the other two coagulants (MgSO4, lime), because the plain settling and coagulation–flocculation process with alum (optimum dosage of 1200 mg/L) resulted in a turbidity removal of 98%, COD reduction of 93%, TSS removal of 98% and color removal of 96% at the pH 6.0 with the sludge volume index of 156 mg/L. This chemically-treated water required further treatment with activated carbon in a batch reactor for up to four hours to meet the paper mill water quality standards. Pollutant reductions at the rate of 99.5%, 99.1%, 99.4% and 99.5% were obtained for turbidity, COD, TSS and color, respectively, with the combination of the sedimentation, coagulation–flocculation process and activated carbon adsorption meeting the production process quality standards. The study revealed that a hybrid end-of-pipe physicochemical treatment was effective in reducing the pollutant load of paper mills effluent and meeting the discharging standards.
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SAMISTRARO, GISELY, e PETER W. HART. "From tree cutting to pulping: the impact of storage time on pulp mill economics". November 2012 11, n.º 11 (1 de dezembro de 2012): 43–49. http://dx.doi.org/10.32964/tj11.11.43.
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Variability in wood properties has a major impact on pulp quality and the cost associated with pulp production. Frequently, accounting data for green tons of wood across the mill scales and the tons of pulp produced suggest that the pulp mill has affected the pulp yield because the tons of purchased wood divided by the tons of pulp produced changes. The current work examines the impact of the time — from when a tree is harvested in the forest to the time it is brought across the scales at the mill — on accounting yield and operating cost. Percentage weight loss (assumed to be changes in moisture content) were determined for Pinus taeda, Eucalyptus dunni, and Eucalyptus grandis over a 12-week period in the winter and summer seasons. Wood samples were obtained immediately after being harvested. The percentage weight loss within the first 5 days of storage varied from 2% to 13%, depending upon species and season, and reached 36% after 11 weeks of storage. For a 1000 tons/day mill with a 55% pulping yield on o.d. fiber, the difference between using fresh-cut wood verses cut trees that have been stored for 11 weeks is 1130 green tons. Assuming the mill pays $45/green ton, the change in green log usage between fresh-cut and 11-week-old logs can cost the mill US$50,850 per day.
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Ruas, D. B., A. H. Mounteer, A. C. Lopes, B. L. Gomes, F. D. Brandão e L. M. Girondoli. "Combined chemical biological treatment of bleached eucalypt kraft pulp mill effluent". Water Science and Technology 55, n.º 6 (1 de março de 2007): 143–50. http://dx.doi.org/10.2166/wst.2007.222.
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Effectiveness of ozonation before and after biological treatment for removal of recalcitrant organic matter in bleached kraft pulp effluents was compared. Two industrial ECF bleached eucalypt kraft pulp effluents (E1 and E2) were pretreated with 100 mg O3/L. Raw and pretreated effluents were treated biologically in bench-scale sequencing batch reactors, under constant conditions. Following biological treatment, effluents were post-treated with 100 and 200 mg O3/L. Effluent pretreatment increased effluent biodegradability by 10% in E1 and 24% in E2. Combined O3-biological treated led to small but significant increases in COD, BOD and lignin removal over biological treatment alone, but pretreatment had no significant effect on effluent colour and carbohydrate removal. Ozone pretreatment did not affect biological activity during treatment of effluent E1 but resulted in a 38% lower specific oxygen uptake rate in effluent E2. At an equivalent dose of 100 mg/L, pre-ozonation produced better quality effluent than post-ozonation, especially with regard to COD and colour. Likewise, when an equivalent dose of 200 mg/L was applied, splitting the dose equally between pre- and post-treatments was more efficient than applying the entire dose in the post-treatment. The potential for combined chemical–biological treatment to improve effluent quality has been confirmed in this study.
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Trung, Thanh, e Tomohide Mogami. "Advanced Online Process Analyzer for Chemical Recovery and Pulp Mill Control". JAPAN TAPPI JOURNAL 74, n.º 1 (2020): 57–66. http://dx.doi.org/10.2524/jtappij.74.57.
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Roy-Arcand, L., e F. S. Archibald. "Ozonation as a Treatment for Mechanical And Chemical Pulp Mill Effluents". Ozone: Science & Engineering 18, n.º 4 (janeiro de 1996): 363–84. http://dx.doi.org/10.1080/01919519608547325.
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From-Aldaron, M., M. Sandberg e K. M. Granström. "Low Dosage Chemical Treatment for Improved Oxygenation of Pulp Mill Effluents". Journal of Environmental Engineering 144, n.º 3 (março de 2018): 06017012. http://dx.doi.org/10.1061/(asce)ee.1943-7870.0001320.
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Zanuttini, M., e V. Marzocchi. "Alkaline Chemi-Mechanical Pulp from Poplar. Relationship between Chemical State, Swelling and Papermaking Properties". Holzforschung 57, n.º 5 (20 de agosto de 2003): 489–95. http://dx.doi.org/10.1515/hf.2003.073.
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Summary In order to analyse the fundamentals of alkaline chemi-mechanical pulping of hardwoods, the chemical state of the wood was related to both the swelling level of fibres and the papermaking properties of pulp. Wafers of poplar wood were alkali treated following a factorial experimental design for two variables: temperature and alkali concentration. Treated wafers were hot defibrated in a 300-mm disk mill at 15% consistency, and then refined in PFI mill at 20% consistency. Results show how fibre swelling gradually increases as alkaline action is increased. The significant improvement in tensile and tear strength of the pulp can, in great part, be ascribed to the development of fibre bonding capacity. A limited effect of ion content on cell wall swelling was found. Swelling correlates well with deacetylation level, and is a major factor in determining the tensile strength and scattering ability of the pulp.
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ANDERSSON, NICLAS, CAROLINE WILKE, TOM BIAZZO, RICK VAN FLEET e ULF GERMGÅRD. "A new sensor and a novel control concept for optimized fiber line operation". October 2014 13, n.º 10 (1 de novembro de 2014): 39–45. http://dx.doi.org/10.32964/tj13.10.39.
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Kraft and sulfite pulp mills use several consecutive process stages for pulp production. However, usually only one key pulp parameter is used for process control and that is the lignin content in the fibers, typically expressed as the kappa number. Even so, to improve process efficiency, more variables need to be monitored. To do that, a new sensor was developed, the dissolved lignin transmitter (DLT), along with a new control concept. The DLT measures the dissolved lignin content in the pulp slurry using a unique principle based on optical measurements. The device can measure the dissolved lignin inline at low consistency and at medium consistency. The sensor has two major applications: 1) improving the efficiency in washing stages and 2) optimizing chemical charges. Results from several mill trials have shown that the contribution from dissolved lignin in the filtrate portion of the pulp is up to 30% of the total bleach load, i.e., fiber and filtrate kappa number combined into the bleach plant. Hence, chemical savings can be achieved taking this component into account compared to only measuring the washed fiber kappa number.
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SAMISTRARO, GISELY, PETER W. HART, JORGE LUIZ COLODETTE e RICARDO PAIM. "Chemical, anatomical, and technology aspects of Eucalyptus benthamii and Eucalyptus dunii for use in an integrated pulp and paper mill". February 2015 14, n.º 2 (1 de março de 2015): 73–81. http://dx.doi.org/10.32964/tj14.2.73.
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Eucalyptus dunii has been commercially used in southern Brazil because of its relatively good frost tolerance and adequate productivity in the winter months. More recently, interest has grown in cultivating Eucalyptus benthamii Maiden & Cambage, which presents even superior frost tolerance compared to E. dunii and is highly productive as well. The quality of E. benthamii for pulp production is not yet proven. Thus, the chemical, anatomical, and technological aspects of pulp made from E. benthamii were compared with those of E. dunii for unbleached paper production. Samples of E. benthamii chips were obtained and analyzed for their basic density, chemical composition, higher heating value, trace elemental analysis, and chip size distribution. The chips were kraft cooked using conditions that produced a 74 ± 6 kappa number. The pulps were characterized for kappa number, yield, viscosity, and morphologic characteristics (e.g., length, wall thickness, and coarseness). Black liquor was analyzed for total solids, organics, inorganics, sodium sulfide, sodium hydroxide, and sodium carbonate. Brownstocks were beaten at five different energy levels in a Valley beater, and the physical strength properties of 120 g/m² handsheets were measured to develop a beater curve. The results of this study showed differences in delignification between the two woods and lower pulp yield for E. benthamii , which are related to their chemical compositions and basic densities. The E. benthamii studied in this work exhibited higher amounts of lignin and extractives, lower carbohydrate content, and lower basic density. However, cooking a blend of the two woods afforded good results in pulping and in physical pulp properties.
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Singh, Ajay Kumar, Adarsh Kumar e Ram Chandra. "DETECTION OF REFRACTORY ORGANIC POLLUTANTS FROM PULP PAPER MILL EFFLUENT AND THEIR TOXICITY ON Triticum aestivum; Brassica campestris AND Tubifex-tubifex". Journal of Experimental Biology and Agricultural Sciences 8, n.º 5 (25 de outubro de 2020): 663–75. http://dx.doi.org/10.18006/2020.8(5).663.675.
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The pulp and paper industry released different chemical pollutants that are directly discharged into the environment without proper treatment. This experiment was carried out to study the effect of pulp paper mill sludge amendments with garden soil (25%, 50%, 75%, and 100%), and garden soil was utilized as a control in a pot experiment. This study revealed the growth parameters of Triticum aestivum and Brassica campestris in germination percentage and germination index values decreased with rising in sludge concentration. Further, Soil amended with 25% paper mill sludge slightly reduced the growth in root length, shoot length, biomass, photosynthetic, and 50% sludge amended soil had variable effects on the root, shoot, and photosynthetic pigment of T. aestivumand B. campestris. However, the toxicity of effluent on tubifex-tubifex worms was also carried out at selected concentrations (25%, 50%, 75%, and 100%). Results of the study suggested that after 24 hours of exposure (>25% concentration), tubifex worms showed various changes such as morphological changes; hemoglobin content disappeared at the lethal concentrations of pulp paper mill effluent; cell bursting, and the back of the body became white with body disintegration at the lethal concentrations of pulp paper mill effluent. This article mainly focuses on the toxicity of the organic pollutants in terrestrial and aquatic life due to pulp paper mill effluent.
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RIVERA, DIEGO F., MAX KLEIMAN-LYNCH, BRENT D. KELLER e STEPHEN F. FRAYNE. "Addressing production bottlenecks and brownstock washer optimization via a membrane concentration system". July 2021 20, n.º 7 (1 de agosto de 2021): 467–78. http://dx.doi.org/10.32964/tj20.7.467.
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Advancements in membrane systems indicate that they will soon be robust enough to concentrate weak black liquor. To date, the economic impact of membrane systems on brownstock washing in kraft mills has not been studied and is necessary to understand the viability of these emerging systems and their best utilization. This study investigated the savings that a membrane system can generate related to brownstock washing. We found that evaporation costs are the primary barrier for mills seeking to increase wash water usage. Without these additional evaporation costs, we showed that our hypothetical 1000 tons/day bleached and brown pulp mills can achieve annual savings of over $1.0 MM when operating at higher dilution factors and fixed pulp production rate. We then investigated the impact of increasing pulp production on mills limited by their equipment. In washer-limited mill examples, we calculated that membrane systems can reduce the annual operating cost for a 7% production increase by 91%. Similarly, in evaporator-limited mill examples, membrane systems can reduce the annual operating cost for a 7% production increase by 86%. These results indicated that membrane systems make a production increase significantly more feasible for these equipment-limited mills.
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Väänänen, P. "Control of the Phosphorus Level of Effluent in the Treatment of Forest Industry Waste Waters". Water Science and Technology 20, n.º 1 (1 de janeiro de 1988): 81–86. http://dx.doi.org/10.2166/wst.1988.0011.
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Pulp and paper mill wastewaters are nutrient deficient, BOD5:N:P may be as low as 100:1:0.2. Now that purification requirements have been tightened, the activated sludge process seems to be most commonly used treatment method. The conventional activated sludge process requires BOD:P ratios of 100 to 0.6 resulting in a need for P addition and hence in a possible increase in the P-level of the effluent. In Finland and also in some other areas phosphorus removal is of great importance in the prevention of eutrophication of watercourses. There are several methods to control phosphorus level, such as biological phosphorus removal, running of the process under starvation of phosphorus, tertiary (chemical) treatment and simultaneous precipitation of phosphorus. This paper lists possible treatment methods and presents more closely chemical treatment using simultaneous precipitation by ferrous sulphate. The results are based on both pilot and full-scale experiments in two kraft pulp mills. The study showed that phosphorus concentration can be reduced to a level of 1.2 mg/l (tot.P) by adding ferrous sulphate to the aeration basin in activated sludge treatment of kraft pulp mill wastewaters. Ferrous sulphate has, also, a slight positive effect on the sludge properties e.g. sludge settleability.
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HART, PETER W. "Differences in bleaching responses from fungal- versus bacterial-derived enzymes". March 2012 11, n.º 3 (1 de abril de 2012): 21–27. http://dx.doi.org/10.32964/tj11.3.21.
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Several mills in North America have been successful in using xylanase enzymes expressed from Trichoderma reesei (a fungus) as part of their bleaching sequence for many years. These mills process hardwood and softwood species, with and without oxygen delignification. These mills also use three-, four-, and five-stage bleaching sequences. North American mills tend to report increased pulp brightness ceilings and decreased bleaching costs as benefits associated with the application of enzymes in the bleaching process. Laboratory testing suggests that eucalyptus pulp is highly susceptible to fungal- and bacterial-derived enzyme bleaching and should result in significant cost savings in South American mills. At least four different mills in South America have attempted to perform enzyme bleaching trials using bacterial-derived enzymes. Each of these mill trials resulted in significantly increased operating costs and/or unsustainable operating conditions. More recently, one of these South American mills performed a short trial using a commercially available, fungal-derived enzyme. This trial was technically successful. This report attempts to determine why the South American mill experiences with bacterial-derived enzymes have been poor, while North American mills and the one South American mill trial have had good results with fungal-derived enzymes. Operating conditions and trial goals for the North and South American mills also were examined.
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Junna, J., e J. Rintala. "Evaluation of Purification Efficiency of Activated Sludge Treatment Plants for Pulp and Paper Industry Wastewaters in Finland". Water Science and Technology 22, n.º 9 (1 de setembro de 1990): 199–206. http://dx.doi.org/10.2166/wst.1990.0083.
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Since 1984, when the first activated sludge treatment plant (ASTP) was built to treat pulp and paper industry wastewaters in Finland, twenty more plants have been introduced by 1989. An evaluation was undertaken to find out the actual performance of the ASTPs in BOD7, CODc r and phosphorus removal. The evaluation included all the 12 ASTPs in operation in the pulp and paper industry at the beginning of 1987. The highest average BOD7 removals were about 90 % at pulp mills as well as paper and board mills. CODc r removal was generally higher at paper and board mills (about 40-70 %) than at pulp mills (about 25-55 %). Phosphorus was added to wastewater in most plants. In some ASTPs, phosphorus concentrations were lowered by 20-40 % compared with wastewater from the mill. In some plants phosphorus load on the recipient was higher than the load coming from the mill. In treated wastewater, correlations between suspended solids and BOD7, CODc r, phosphorus and nitrogen were significant in most plants. This indicated that low removal efficiencies resulted from poor suspended solids removal in the secondary clarification. Volumetric and sludge CODc r loading rates could not explain removal efficiencies when all plants were included in the comparison. In plants treating chemical pulping effluents, higher removal efficiencies were normally achieved with lower loading rates. When the plants were studied separately, the influence of loading rate was generally significant.