Isoaho J.P.,University of Jyvaskyla |
Tarkkanen S.,University of Jyvaskyla |
Alen R.,University of Jyvaskyla |
Fiskari J.,Oy Metsa Botnia Ab |
Fiskari J.,University of Helsinki
Nordic Pulp and Paper Research Journal | Year: 2012
Softwood-based kraft mill bleaching effluents from the initial bleaching stages D0 and E1 (the bleaching sequence being D0E1D 1E2D2) were treated by the oxidative Fenton method (H2O2-FeSO4) to decompose organic pollutants containing adsorbable organic halogens (AOX). Experiments designed using the Taguchi method were applied to predict the process conditions that would result in a cost-effective and adequate removal of AOX. In addition to the composition and concentration of the reagents (H2O2 and Fe2+), the main process parameters selected were temperature and reaction time, while pH was adjusted to an approximate value of 4 (the volumetric ratio of the mixed effluents D0:E1 was 3:2). The results indicated that an AOX removal of about 70% for this mixture (corresponding to about 50% for the mill) was achieved when the effluent samples were treated for 60 min at 70°C with H2O2 and Fe 2+ at a concentration of 1600 mg/l and 28 mg/l, respectively.
Poykio R.,Valtakatu 26 |
Kivilinna V.-A.,Oy Metsa Botnia Ab |
Nurmesniemi H.,Stora Enso
Chemija | Year: 2010
Tis study presents the most recent data on Na and Ca concentrations in Scots pine (Pi-nus sylvestris L.) needles sampled in bioindicator surveys carried out in 2009 at Kemi (Northern Finland), as well as at Pietarsaari (Western Finland) in 2007, at Eno (Eastern Finland) in 1994-1996 and in the Jyväskylä region (Central Finland) in 2006, which are areas with operating pulp and paper mills. Na and Ca concentrations in Scots pine needles at Kemi varied within 7-280 mg/kg (d. w.) and 1 410-5 450 mg/kg (d. w.), respectively. Na concentrations in both C and C + 1 needles at Kemi in 2009 were in good agreement with the values of 31-105 mg/kg (d. w.) and 54-151 mg/kg (d. w.), respectively, observed at Eno. Ca concentrations in C + 1 needles at Kemi were in good agreement with the values of 2 432-5 598 mg/kg (d. w.) observed at Pietarsaari in 2007 and with the values of 2 700-7 900 mg/kg (d. w.) observed in the Jyväskylä region in 2006, although the highest Ca concentrations - 7 900 mg/kg (d. w.) - in the C + 1 needles in the latter area was obviously higher than the corresponding value of 5 450 mg/kg (d. w.) observed in our study at Kemi. © 2012 Lietuvos mokslu̧ akademija.
Antonsson S.,KTH Royal Institute of Technology |
Pulkkinen I.,Aalto University |
Fiskari J.,Oy Metsa Botnia Ab |
Karlstrom K.,KTH Royal Institute of Technology |
And 2 more authors.
Appita Journal | Year: 2010
Hygroexpansion coefficient and tensile stiffness are important parameters in many paper applications. This study compares several bleached industrial hardwood kraft pulps, comprising five eucalypt pulps from South America, Europe, and Africa as well as an acacia pulp from Asia and a birch pulp from Scandinavia. Refined and unrefined pulps are compared. The results indicate significant differences in hygroexpansion but smaller differences in tensile stiffness index at comparable densities. No single factor offering a reasonable explanation of these differences in hygroexpansion coefficient, such as carbohydrate composition, fibre dimensions, or fibre form, was found. However, correlation between hygroexpansion coefficient and the mechano-sorptive creep stiffness was observed. We suggest that the hygroexpansion coefficient at a given tensile stiffness level can be used to rank pulps in terms of their mechano-sorptive creep properties.
Long-term changes in the effluent loads from pulp and paper mills, the introduction of BAT technology, and their effects on extractable organic halogens concentrations in sediment in part of the Bothnian Bay
Poykio R.,City Hall |
Nurmesniemi H.,Stora Enso |
Kivilinna V.A.,Oy Metsa Botnia Ab |
Kuokkanen T.,University of Oulu
Water Science and Technology | Year: 2010
The Bothnian Bay at Kemi, which is the northernmost basin of the Gulf of Bothnia in the Baltic Sea, is affected by effluents from point sources such as pulp and paper mills and municipal sewage plant. During the period 1988-2008, the accumulated values of effluent volume, BOD7, CODCr, Tot-P, Tot-N, TSS and AOX from these point sources fell considerably as follows: 1) effluent volume by 24%, BOD7 by 92%, CODCr by 74%, Tot-P by 79%, Tot-N by 38%, TSS by 76% and AOX by 93%. The decrease in the effluent loadings is due to the introduction of Best Available Techniques (BAT) for the production processes and wastewater treatment at the pulp and paper mills. According to the long-term monitoring program that has been carried out every third year between 1997-2009, the decreasing trend in EOX - concentrations in the top 2 cm of the bottom sediment reflects the decrease in organochlorine discharges (AOX) from the mills. In 1997, the EOX concentrations in bottom sediment varied between 3-70 μg of Cl g-1 (dry weight), and in 2009 between 1.2-31 μg of Cl g-1 (dry weight). © IWA Publishing 2010.
Ruiz J.,Centro Tecnico do Papel |
Sacon V.M.,Votorantim Celulose e Papel |
Silva F.P.,Votorantim Celulose e Papel |
Eichhorn S.,SCA HYGIENE PRODUCTS GmbH |
And 6 more authors.
O Papel | Year: 2010
A method for producing specific handsheets to assess the pulp potential softness for tissue manufacture was developed. A panel of people was formed and trained to evaluate the softness of tissue products and the softness of these handsheets. A protocol was designed for pulp softness assessment. 13 market bleached pulps - 7 eucalyptus, 3 softwoods, 2 hardwoods and 1 deinked pulp -, were studied for their softness potential before and after refining, according to the developed pro tocol. Ranking these pulps was possible and their softness assessment revealed important differences between the pulp grades, and according to refining. Hardwood pulps - and more particularly eucalyptus pulps -, produced the softest papers, whereas softwood pulps presented the lowest softness potential. Furthermore, the hardwood pulps lost less in softness potential during conventional refining than the softwood pulps. Their softness rating remained positive, whereas that of the softwood pulps always presented a negative value. A statistical model was developed for predicting pulp softness from the fibre characteristics. This model was proven sufficiently reliable and used to determine pulp softness potential, and then follow the softness through tissue manufacture, especially during the stock preparation and pulp refining. Finally, a comparison between the CTP - Centre Technique du Papier, France - panel results and those of four other panels was made, demonstrating that the five panels could evaluate softness in the same manner, and that the new protocol for assessing softness on specific handsheets was relevant for such an application.