In the early 1990s polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) contamination of fish was widely associated with bleached kraft pulp mills. Regulations were put into place in Canada and elsewhere to reduce or eliminate the presence of these chemicals in pulp mill effluents. The industry quickly introduced treatment and process changes such as elemental (ECF) and total chlorine free (TCF) bleaching, which resulted in dramatically reduced PCDD/F concentrations in pulp mill effluents. However, PCDD/Fs may remain a concern for the receiving environment near bleached kraft pulp mills due to their tendency to persist in sediments and bioaccumulate in aquatic biota. Several studies conducted in the early 1990s reported significantly elevated levels of PCDD/Fs in white sucker (Catostomus commersoni) exposed to bleached kraft mill effluent (BKME). Particularly high concentrations were observed in the receiving environment of two mills in northern Ontario. The first mill, located in the town of Terrace Bay, discharges effluent into Jackfish Bay, Lake Superior. The second mill is located in Smooth Rock Falls, Ontario and discharges effluent into the Mattagami River where effects have been observed in fish collected downstream of the pulp mill. Over time, both mills have undergone a number of process upgrades, including a transition to 100% chlorine dioxide (ClO2) substitution. In 2006 the Tembec Smooth Rock Falls Pulp and Paper Mill closed permanently, while the mill in Terrace Bay has gone through a number of temporary shutdowns and is currently in the process of transitioning to a dissolving pulp process. Temporal changes in PCDD/F contamination was examined in white sucker historically exposed to BKME in Jackfish Bay and the Mattagami River, following mill process changes and closures. Historical data was summarized from studies conducted in the 1990s and analyzed along with liver tissue of male white sucker collected from each location in 2011 and 2012. The body burden of each fish was analysed using Toxic Equivalency (TEQ) calculations to account for concentration and relative toxicity of 2,3,7,8??? substituted PCDD/F congeners. At Jackfish Bay, concentrations of PCDD/Fs in surface sediment and dated sediment cores were used to document the spatial and temporal pattern of PCDD/F contamination in relation to historical process upgrades and operational changes at the mill. PCDD/Fs measured in white sucker liver samples collected from Jackfish Bay during gonadal recrudescence in the fall illustrate a decrease in mean TEQ from 74.2 ?? 20.9 pg???g-1 in 1991 to 3.34 ?? 2.05 pg???g-1 in 2012. These values were slightly elevated compared to the remote reference location at Mountain Bay, Lake Superior, which exhibited a mean TEQ of 1.88 ?? 0.45 pg???g-1 and 1.06 ?? 0.69 pg???g-1 in white sucker collected in fall 2011 and 2012, respectively. Although below consumption guidelines, trace levels of PCDD/Fs persist in fish collected from Jackfish Bay and these concentrations are suspected to reflect sediment contamination in Moberly Bay (part of Jackfish Bay). A unique PCDD/F contaminant profile, dominated by 2,3,7,8??? tetrachlorodibenzo???p???dioxin (TCDD) and dibenzofuran (TCDF), was observed in white sucker and sediment collected from Jackfish Bay. Analysis of surface sediment collected throughout Jackfish Bay revealed elevated PCDD/F concentrations, compared to reference areas in Lake Superior. TEQ values measured in surface sediment from the depositional areas of Moberly Bay exceeded the Canadian Council of Ministers of the Environment (CCME) guidelines. In 1991 PCDD/F contamination, reported as mean TEQ, of white sucker collected downstream of the pulp mill outfall in Smooth Rock Falls reached levels of 111 ?? 86.2 pg???g-1. At the time, the mill utilized molecular chlorine (Cl2) in the bleaching sequence and employed primary effluent treatment. A dramatic decline was observed in PCDD/F concentrations of fish collected in 1993 and 1995, corresponding to implementation of 100% ClO2 substitution in the bleaching process. PCDD/F contamination in white sucker collected from the Mattagami River in 2011 and 2012 were similar upstream (0.53???1.49 pg TEQ???g-1) and downstream (0.75???2.87 pg TEQ???g-1) of the historical pulp mill outfall at Smooth Rock Falls, suggesting a return to background condition following the 2006 mill closure. Levels of 2,3,7,8???TCDD and 2,3,7,8???TCDF in liver tissue of fish collected downstream declined drastically compared to concentrations measured in 1991. The PCDD/F congener profile observed in white sucker downstream in 2011 and 2012 was more similar to fish collected from the reference site upstream than exposed fish collected in 1991. No sediment depositional areas suitable for taking a core sample were found on the river downstream of Smooth Rock Falls due to the nature of the system. This study supports the conclusion that particulate (POM) and dissolved organic matter (DOM) from continuous inputs of effluent were likely the primary source of PCDD/Fs to fish in these receiving environments, with only a small contribution from surface sediment. Results indicate a decreasing trend in PCDD/F contamination of white sucker historically exposed to bleached kraft pulp mill effluent in the receiving environments of Jackfish Bay and the Mattagami River, consistent with mill process upgrades to eliminate the use of elemental chlorine from the bleaching sequence. Current levels of PCDD/Fs measured in white sucker collected from these locations suggest a return to background condition.

The pulp and paper industry in New Zealand annually produces over one hundred thousand dry tonnes of solid waste due to the treatment of pulp and paper mill effluents, the majority of which is currently landfilled. The New Zealand Waste Management Strategy (2002) has set a target for the diversion of commercial organic wastes from landfill to beneficial use to exceed 95% by 2010 . Effluents produced by softwood pulp mills, such as in New Zealand, contain high concentrations of naturally derived resin extractive compounds that are toxic to fish and other aquatic organisms. Improvements in waste water treatment technology has enabled the industry to meet rigorous discharge standards, however, this has resulted in an increase in the production of pulp mill effluent solids which require disposal. This has become an issue for the pulp and paper industry, especially as current landfill space is limited. Land application has been used for many years as a means of disposal of pulp mill wastes. While most studies investigating land application of pulp mill effluent solids have concluded that the risk posed to the environment is low, few have investigated the potential toxicity of these wastes to soil organisms, and these studies did not directly address the effects of resin extractive compounds. Resin extractives have been shown to be recalcitrant and to accumulate in anaerobic sediments. It is not known to what extent resin extractives are bioavailable or degradable in land applied Pulp mill effluent solids (PMES), or their potential to bioaccumulate in soil organisms. This PhD thesis research sought to extend the knowledge on the environmental fate and effects of pulp mill effluent wastes. It focused on terrestrial systems, which have not been well studied in this respect. Four chemically distinct softwood pulp mill effluent solids, a primary treatment solid and three secondary treatment biosolids, were used to investigate their effects on soil organisms and soil functions. An interdisciplinary approach was adopted, which incorporated three main areas of study, as follows: 1. A comprehensive resin extractives analysis of the pulp mill effluent solids undertaken so that effects on soil organisms and soil functions could be related to the resin extractives chemistry of the individual pulp mill effluent solids tested. 2. A battery of bioassays used to investigate the toxicity of the selected pulp mill effluent solids. 3. A field trial set-up to investigate how pulp mill effluent solids affected soil functions and also to investigate the decomposition of pulp mill effluent solids and of resin extractives in these solids. Three hypotheses tested were: I. Pulp mill effluent solids are toxic to soil organisms. II. Resin extractives in pulp mill effluent solids are recalcitrant in the terrestrial environment. III. Pulp mill effluent solids will cause significant measurable negative impacts on soil functional capacity. A wide range of resin extractives compounds were identified in pulp mill effluent solids, and concentrations of individual compounds varied widely between the different pulp mill effluent solids tested. During the two years after field application of the pulp mill effluent solids, resin extractives declined, however, decay rates of individual compounds were variable. The decay rate of compounds was influenced by the type of pulp mill effluent solids containing these compounds and not by the initial concentration of compounds. All compounds, including resin acids, degraded rapidly in the applied primary solid and in one of the applied biosolids, with average half-lives calculated ranging from three to twelve months. In the other biosolids, resin acids were recalcitrant with average half-lives calculated to be nearly ten years. Laboratory bioassays conducted on oats, earthworms and enchytraeid worms indicated that pulp mill effluent solids had low toxicity to these organisms. An aquatic bioassay organism, however, was acutely affected by aqueous extracts from pulp mill effluent solids. Earthworms were shown to bioaccumulate some resin extractive compounds to a limited extent, indicating that resin extractives were bioavailable in pulp mill effluent solids. Enchytraeid reproduction was reduced by exposure to some pulp mill effluent solids but this was not correlated to resin extractives concentration of the solids tested. Field applied pulp mill effluent solids significantly enhanced the fluxes of CO2 from the soil surface. When mass losses of pulp mill effluent solids carbon were taken into account, it was shown that these solids had little effect on soil respiration. Needle litterbags were placed above and below pulp mill effluent solids and in the litter horizon of a control treatment for 12 months. Needle litter decomposition was not significantly different between treatments, however, changes in enzyme activities were detected in litter beneath pulp mill effluent solids compared to control needle litter that had not been exposed to pulp mill effluent solids. The decomposition rate of field applied pulp mill effluent solids was slow, with half-lives extrapolated to be between five and twenty five years. The decomposition rate appeared to be influenced by the pools of carbon available for decomposition, with primary solids decaying significantly faster than biosolids due to a higher cellulose component. The conclusions of the PhD thesis research are, therefore, that generally, pulp mill effluent solids used in the study were demonstrated to be relatively benign and appear to pose a low risk to the terrestrial ecosystem when applied to soil. However, a cautious approach is still recommended to land application, based on the extensive evidence of disruption to aquatic ecosystems, and because pulp mill effluent solids will take many years to decompose and resin acids are recalcitrant in some pulp mill effluent solids. Further research is recommended to elucidate mechanisms of action by resin extractives in soil organisms and the ultimate fate of these compounds in the soil compartment.

Recent studies have shown that dehydroabietic acid (DHAA), a resin acid present in pulp and paper mills, may have anti-estrogenic effects in fish. A chronic-exposure toxicity experiment using immature rainbow trout (Oncorhynchus mykiss) was conducted in order to assess the endocrine disrupting and liver metabolic effects of the wood extractives DHAA and β- sitosterol (BS) regularly present in pulp and paper mills and the model estrogen 17β-estradiol (E2). It was found that exposure to 5 ppm of E2 significantly increased hepatosomatic index (HSI), vitellogenin (VTG) and plasma sorbitol dehydrogenase (SDH). This effect was reduced by mixing E2 with DHAA, indicating that DHAA does not cause its anti-estrogenic effects indirectly due to liver damage. Exposure to 5 ppm of DHAA caused a significant increase in liver citrate synthase (CS), and liver ethoxyresorufin-O-deethylase (EROD) activity after 7 days, however, the fish recovered by 28 days. This study also determined the effect of 14 different pulp and paper mill effluent extracts on liver enzyme metabolism through alterations in the activity of liver lactate dehydrogenase activity (LDH) and CS. This activity varied greatly between mills but most showed an induction of CS after 28 days exposure through i.p. injection. The results of the study indicate that DHAA may alter energy metabolism as well as cause anti-estrogenic effects in female juvenile rainbow trout. / UOIT

Os efluentes de fábricas de celulose são conhecidos por apresentarem uma ampla gama de compostos químicos naturais e antropogênicos, que possuem potencial inibidor e estimulador à biota. Muitos destes podem se agregar ao sedimento e causar efeitos agudos ou crônicos aos organismos. Diversos estudos têm sido realizados para se avaliar a qualidade ambiental do corpo receptor adjacente às fábricas de celulose, entretanto a maioria destes são avaliados de forma isolada, o que dificulta a identificação das áreas realmente afetadas pelo efluente. A abordagem TQS (Tríade de Qualidade dos Sedimentos) integra análises químicas do sedimento, testes de toxicidade e ecologia do bentos. O objetivo do presente trabalho foi avaliar a qualidade dos sedimentos no entorno do emissário de uma fábrica de celulose, através da abordagem TQS. Foram feitas 4 amostragens, em julho e dezembro de 2001 e 2002. O sedimento foi coletado em 9 estações de amostragem, sendo 6 ao redor do emissário da fábrica e 3 afastadas do mesmo (referência). Foram realizadas análises químicas (metais pesados, ácidos graxos, beta sitosterol, EOX, PCBs, N, C, etc.) do sedimento, testes de toxicidade da água intersticial (MICROTOX® e ouriço Echinometra lucunter) e sedimento (anfípodo Tiburonella viscana) e análise da estrutura da comunidade do zoobentos. A análise integrada dos dados da tríade mostrou uma baixa influência do efluente da fábrica na estação de coleta mais próxima do emissário (5) e em duas estações ao sul do mesmo (3 e 7A). A Estação 5 apresentou evidências químicas e toxicológicas de degradação, enquanto que as Estações 3 e 7A apresentaram evidências químicas. / Effluents from pulp mills are known to contain a large number of chemicals that have inhibitory and stimulatory effects on aquatic biota. Many contaminants may adsorb to sediment and cause acute or chronic effects to sediment-dwelling organisms. Several studies have been conducted to evaluate the environmental quality of the receiving body adjacent to a pulp mill (Brazil) outfall. However, most of them were conducted separately, making it difficult to identify the real affected area. The SQT (Sediment Quality Triad) approach integrates chemical analyses of the sediment, toxicity tests and benthic ecology. The purpose of the present study was to evaluate the sediment quality around the outfall of a pulp mill by use of the SQT approach. Samples were collected seasonally over two years, in July and December of 2001 and 2002. The sediment was collected at nine sampling stations, six of them around the outfall and three reference stations located far from the outfall. Several chemical analyses were made (heavy metals, fatty acids, beta sitosterol, EOX, PCBs, N, C) in the sediment, toxicity tests were done with pore water (MICROTOX® and the sea urchin Echinometra lucunter early life stage tests) and sediment (amphipod Tiburonella viscana), and analyses of the structure of the zoobenthic community were performed. The integrated analysis of the SQT data showed some influence, although low, of the effluent on the sampling station closest to the outfall (station 5) and on two stations to the south of the outfall (stations 3 and 7A). Station 5 exhibited evidence of toxicological effects, and stations 5, 3 and 7A exhibited slightly elevated concentrations of chemicals relative to the reference stations.

Mitigation of climate change and energy security are major driving forces for increased biomass utilization. The pulp and paper industry consumes a large proportion of the biomass worldwide including bark, wood residues, and black liquor. Due to the fact that modern mills have established infrastructure for handling and processing biomass, it is possible to lay foundation for future gasification based bio-refineries to poly-produce electricity, chemicals or bio-fuels together with pulp and paper products. There is a potential to export electricity or bio-fuels by improving energy systems of existing chemical pulp mills by integrating gasification technology. The present study investigates bio-fuel alternatives from the dry black liquor gasification (BLG) system with direct causticization and direct methane production from the catalytic hydrothermal gasification (CHG) system. The studied systems are compared with bio-fuel alternatives from the Chemrec BLG system and the improvements in the energy systems of the pulp mill are analyzed. The results are used to identify the efficient route based on system performance indicators e.g. material and energy balances to compare BLG systems and the conventional recovery boiler system, potential biofuel production together with biomass to biofuel conversion efficiency, energy ratios, potential CO2 mitigation combining on-site CO2 reduction using CO2 capture and potential CO2 offsets from biofuel use, and potential motor fuel replacement. The results showed that the dry BLG system for synthetic natural gas (SNG) production offers better integration opportunities with the chemical pulp mill in terms of overall material and energy balances. The biofuel production and conversion efficiency are higher in the CHG system than other studied configurations but at a cost of larger biomass import. The dry BLG system for SNG production achieved high biomass to biofuel efficiency and considerable biofuel production. The energy ratio is significant in the dry BLG (SNG) system with less biomass demand and considerable net steam production in the BLG island. The elimination of the lime kiln in the dry BLG systems resulted in reduced consequences of incremental biomass import and associated CO2 emissions. Hydrogen production in the dry BLG system showed the highest combined CO2 mitigation potential i.e. on-site CO2 capture potential and CO2 offset from biofuel replacing fossil fuel. The results also showed that the motor fuel replacement potential with SNG as compressed natural gas (CNG) replacing gasoline in the transport sector is significantly high in countries with large pulp industry. / QC 20120528

Anaerobic digestion of excess biological wastewater treatment sludge (WAS) from pulp mills has the potential to reduce disposal costs and to generate energy through biogas production. The organic matter in WAS is highly structured, which normally hinders biogas production. This study investigated three methods of pretreating WAS from two different pulp mills before anaerobic digestion to improve biogas yield and production rate. The three pretreatment methods tested were: i) thermal pretreatment at 170oC, ii) caustic pretreatment at 140oC and pH 12, and iii) sonication at 20 kHz and 1 W/mL. Thermal pretreatment proved to be the most effective, increasing biogas yield by 280% and 50% and increasing production rates 300-fold and 10-fold for the two samples, respectively. Caustic pretreatment showed similar results, but resulted in the formation of soluble non-biodegradable compounds. Sonication was the least effective pretreatment and did not substantially increase biogas yield, but increased biogas production rate.

Anaerobic digestion of excess biological wastewater treatment sludge (WAS) from pulp mills has the potential to reduce disposal costs and to generate energy through biogas production. The organic matter in WAS is highly structured, which normally hinders biogas production. This study investigated three methods of pretreating WAS from two different pulp mills before anaerobic digestion to improve biogas yield and production rate. The three pretreatment methods tested were: i) thermal pretreatment at 170oC, ii) caustic pretreatment at 140oC and pH 12, and iii) sonication at 20 kHz and 1 W/mL. Thermal pretreatment proved to be the most effective, increasing biogas yield by 280% and 50% and increasing production rates 300-fold and 10-fold for the two samples, respectively. Caustic pretreatment showed similar results, but resulted in the formation of soluble non-biodegradable compounds. Sonication was the least effective pretreatment and did not substantially increase biogas yield, but increased biogas production rate.

L’atelier de régénération d’une usine kraft permet d’extraire des liqueurs noires les élémentschimiques nécessaires à la cuisson du bois et de les régénérer sous leur forme active, ainsi quede valoriser la fraction organique dissoute sous forme de chaleur. Les opérations unitaires enoeuvre sont nombreuses, complexes, et souvent mal décrites. Ce travail vise à permettre unemeilleure compréhension de la régénération, par la réalisation de modèles fiables décrivant lesphénomènes et processus dans chaque opération unitaire, leur implémentation algorithmiqueet leur exploitation par la simulation du procédé global. / Chemical recovery at the kraft mill is the process whereby the valuable inorganic elements areextracted from spent kraft liquors and regenerated under their form effective to the cooking ofthe wood and energy is producted from the dissolved organic fraction. Many unit operations areinvolved, often poorly described. This work aims at a better understanding of the recovery processes.Reliable models describing the physical phenomena were proposed for each operation andimplemented as a computer algorithm. The whole chemical recovery unit was then simulated.

Syftet med det här examensarbetet är att undersöka möjligheter för energieffektivisering i form av ökad värmeåtervinning hos Ahlström-Munksjö Aspa Bruk AB med målet att föreslå åtgärder som minskar behovet av färskånga till uppvärmning i processerna. Detta har gjorts med hjälp av en pinchanalys där de externa behoven, pinchöverträdelser och effektiviseringsmöjligheter har identifierats och analyserats för att avgöra hur effektiv värmeväxlingen på Aspa Bruk är. Strömdata har samlats in på plats på bruket främst genom givare som loggar data kontinuerligt men även genom mätningar, miljöbesiktningsrapporter och antaganden.  Ur pinchanalysen framkom det att de externa värmebehoven potentiellt skulle kunna reduceras med ca 19,2 MW, vid ett så energieffektivt system som möjligt, jämfört med dagens behov av färskånga som ligger på 71,5 MW. I praktiken är det dock inte möjligt att genomföra åtgärder för att minska det externa värmebehovet fullständigt till följd av tekniska- och ekonomiska begränsningar. Pinchöverträdelser står för ca 7,7 MW av de ca 19,2 MW och återfinns i sekundärvärmesystemet då det råder överskott av värme i varmvatten- och hetvattenproduktionen.  De åtgärdsförslag som läggs fram bygger på att effektivisera energianvändningen och avlägsna pinchöverträdelser med åtgärder som anses genomförbara. Tre åtgärder presenteras:  Använda värmeenergin från rökgaserna från sodapannan för att förvärma förbränningsluften till sodapannan och därmed ersätta delar av färskångan som används till detta. Öka andelen flashånga från tank 2 till förbasningsfickan där flisen förvärms innan kokaren istället för terpentinkondensorn. Detta skulle medföra en reducering av färskånga till förvärmningen av flisen.  Eliminera 3 bars ångan till hetvattentanken och kompensera med ett ökat varmvattenflöde genom ett ökat intag av råvatten som ska bli varmvatten.  Totalt skulle dessa åtgärder potentiellt kunna minska förbrukningen av färskånga med ca 12,5 MW. Potentiellt skulle även mer ånga kunna sparas om rökgaserna från sodapannan tilläts kondensera. Åtgärdsförslag nummer 3 är den som bidrar mest till reduceringen av färskånga på Ahlstrom-Munksjö Aspa Bruk AB. / The purpose of this master’s thesis is to investigate opportunities for a higher energy efficiency in terms of increased heat recovery at Ahlstrom-Munksjö Aspa Bruk AB with the goal of suggesting actions that reduces the need for live steam in process heating. In order to do this a pinch analysis was conducted where the utility consumptions, pinch violations and opportunities for increased energy efficiency were identified and analyzed in order to determine how efficient the heat exchange at Aspa Bruk is. Stream data was gathered at the mill mainly through continuously logging sensor data but also through measurements, environmental inspection reports and assumptions.       From the pinch analysis it was discovered that the external hot utility potentially could be reduced by approximately 19,2 MW given that the system would be as energy efficient as possible, compared to the current need of live steam that is 71,5 MW. However, in reality it is not possible to accomplish this reduction due to technical and economic limitations. Pinch violations stand for about 7,7 MW of the 19,2 MW and are located in the secondary heat system since there is an excess of heat in the warm water- and hot water production.  The actions suggested are based on increasing the efficiency of the energy consumption and removing pinch violations and are also considered feasible. Three suggestions are presented:  Recover the heat in the fumes from the recovery boiler and use it to preheat the combustion air in to the recovery boiler and thereby replace some of the live steam used for this.  Increase the amount of flash steam from tank 2 to the preheating of the woodchips before the boiler by reducing flash steam to the turpentine condenser. This would lead to a reduction in live steam used to preheat the woodchips. Eliminate the 3-bar live steam to the hot water tank and compensate it by increasing the amount of cold water that is going to become warm water.  In total, these proposed arrangements will potentially lead to a reduction in the use of live steam of approximately 12,5 MW. Potentially even more live steam can be saved if the fumes from the recovery boiler are allowed to condense. Number 3 amongst the proposed actions is the one that has the biggest influence on the reduction of live steam at Ahlstrom-Munksjö Aspa Bruk AB.

Abstract This thesis aims to increase our knowledge about the characteristics of chemical pulp process and wastewaters and how problematic substances, e.g. wood extractives, could be removed effectively and selectively by coagulation–flocculation with either internal or external water treatment. Characterization was performed by investigating kraft pulp bleaching filtrates, as well as wastewater, before (influent) and after (effluent) the activated sludge treatment by means of a range of chemical analyses and by carrying out size fractionation studies. Cationic polyelectrolytes were used to purify oxygen stage bleaching filtrate, and charge analyses (zeta potential, charge quantity) were carried out in order to understand the coagulation phenomenon. In activated sludge treatment, the enhancement of particle removal, either by filtration or using a chemical in the primary clarifier, would lead to savings in aeration costs and result in a more stable process. Microfiltration already with a large pore size (8 µm) removed 30–50% of the wood extractives from the influent. Separate treatment stages for certain wastewater fractions, e.g. debarking plant effluent, would ensure cost-efficiency. After the activated sludge process, the wood extractives were present as particles (18%) and < 3 kDa fraction (82%). β-sitosterol occurred only in particles in the effluent. The release of harmful components into the environment could be decreased by microfiltration (e.g. 0.45 µm) of the final effluent or using a chemical in the secondary clarifier. Interestingly a huge increase in BOD was realized in the 3 kDa fraction of both influent and effluent, which indicated the presence of toxic substances in the larger fractions. After passing the effluent into the water system, there might be a similar jump in the BOD because the effluent is diluted many-fold. This would contribute to the formation of areas with an oxygen deficit. In the coagulation–flocculation studies, effective and selective removal of wood extractives (92%) from the oxygen stage filtrate was obtained with a cationic polyelectrolyte of medium molecular weight and medium charge density at 72 °C and pH 5–6. The multimodal zeta potential distribution gave more information than the average zeta potential. Aggregation of colloidal particles occurred when only one zeta potential was observed. The number of different zeta potentials diminished with decreasing pH and after exceeding a certain polyelectrolyte dosage level.