Hallsta paper mill uses large amounts of water during the pulp and paper making processes. The wastewater is treated in two separate activated sludge processes referred to as BIO 1 and BIO 2. The main aim is to reduce the organic substance content, measured as COD (Chemical Oxygen Demand) before the wastewater is released into the environment. Since the effluent produced is very rich in organic substances, the addition of nitrogen (N) and phosphorus (P) are necessary to give satisfactory treatment results. Problems with sludge bulking sometimes occur which lead to increased levels of suspended matter and nutrients in the effluent. Periods of high concentration of phosphorus is also of great concern. The aim of this study is to investigate the causality behind the sludge bulking, with the help of scientific literature and analysis of previously compiled data using multivariate data analysis. COD and nutrients present in the influent will also be surveyed to identify variations in concentration caused by the paper making process. The scientific literature points toward low nitrogen and phosphorus levels as the major causes of the bulking sludge, as this leads to increased growth of filamentous bacteria to the detriment of the preferred flocculating species. A full scale experiment was conducted in an attempt to evaluate sufficient dosage levels of N and P to reduce this problem. The experiment has produced stabile results with low percentages of suspended organic matter and nutrients. Evaluation of the previously collected data using Multivariate Data Analysis did not lead to any correlation between variables being found, other than the impact of sludge concentration on COD-reduction. No relevant explanation to periods of high phosphorus levels could be found neither in the scientific literature nor in the multivariate data analysis. Bleaching of the paper pulp, with hydrogen peroxide and lye, results in a subsequent increase in COD concentration in the wastewater. The study shows an increased COD in the water approximately 12 hours after the increased dosing of these bleaching agents. Also the amounts of easily degradable COD increases following increased dosage of hydrogen peroxide and lye. The content of easily accessible phosphorus in the influent represents a minimum of 25 % and 20 % of the amount theoretically required for BIO1 and BIO2 respectively. The influent levels of nitrogen represents 33 % and 100 % for BIO1 and BIO2 respectively. From this study it has been possible to deduce that a controlled dosage of nutrients in relation to the incoming level of COD, is of great importance to the efficient treatment of COD rich effluent in the systems under investigation at Hallsta Papermill. / Vid Hallsta Pappersbruk används stora mängder vatten vid tillverkningen av massa och papper. Det förorenade processvattnet renas i två separata anläggningar, BIO1 och BIO2, båda med biologisk rening av typen aktivt slam. Avloppsvattnets höga halter av kolföreningar, vilka analyseras som COD (Chemical Oxygen Demand), kräver extra tillsats av kväve och fosfor för att erhålla tillfredsställande reningsresultat. I den biologiska reningen uppstår periodvis problem med slamsvällning, något som resulterar i höga utsläpp av suspenderat material och organiskt bundna näringsämnen. Även perioder med höga fosforutsläpp förekommer. Syftet med examensarbetet är att genom litteraturstudier och analys av historiska data, med hjälp av multivariat dataanalys, utreda orsakerna till problemen. Även en kartläggning av variationerna i inkommande avloppsvatten med avseende på COD och lättillgängliga näringsämnen genomförs. Utifrån information från litteraturen tyder problemen med slamsvällning ofta på bristande tillgång på kväve och fosfor vilket bland annat kan resultera i kraftig tillväxt av filamentösa bakterier. För att komma till rätta med problemen startades ett styrt försök med beräknade optimala doseringskvoter. Försöket resulterade i stabil drift för båda anläggningarna med låga utsläppsnivåer av både suspenderat material och näringsämnen. Resultatet från utvärderingen av driftsdata med multivariat analys visar att slamhalten har betydelse för COD-reduktionen i BIO1. Någon förklaring till problemen med höga fosforutsläpp har inte framkommit vare sig ur litteraturstudie eller multivariat dataanalys. Vid alkalisk oxiderande blekning av termomekanisk pappersmassa ökar den totala COD-koncentrationen i avloppsvattnet i samband med höjd dosering av blekkemikalier. Studien visar att en ökad COD-koncentration kan observeras i vattnet in till BIO1 ca 12 timmar efter förhöjd dosering av blekkemikalier. Samtidigt ökar andelen lättnedbrytbart COD till följd av ökad blekningsgrad. Kartläggningen av inkommande vatten visar att mängden lättillgängligt kväve i avloppsvattnet in till biologierna motsvarar ca 33 % och 100 % av det teoretiskt beräknade behovet för BIO1 respektive BIO2. För fosfor uppgår motsvarande till minst 25 % respektive 20 % för BIO1 och BIO2. Under examensarbetets gång har det kunnat konstateras att dosering av närsalter i förhållande till inkommande mängd COD är av stor vikt för en väl fungerande rening av det COD-rika avloppsvattnet vid Hallsta Pappersbruk.

This thesis work was made for Södra Cell Mörrums bruk in Blekinge. The purpose of the work was to develop a computer model in the simulation program Extend for the removal and balance of organic oxygen consuming substances, measured as COD (Chemical Oxygen Demand), in the new biological treatment plant in the mill. The plant produces two different pulp products, TCF- (Totally Chlorine Free) pulp and ECF- (Elementary Chlorine Free) pulp, for sale. The different bleaching procedures affect the characteristic of the wastewater and thus the effectiveness of the biological treatment plant. In the model that was developed the COD in the wastewater was divided into five different COD-fractions: soluble easily degradable (SS), soluble hardly degradable (SR), soluble inert (SI), particulate inert (XI) and particulate biomass (XB). To create the model FlowMac™ was used as a base. FlowMac™ is a library module in Extend adapted for pulp and paper mills. Some of the blocks only needed a slight modification while others, for example the sedimentation basin and the bioblocks, had to be done from scratch. The calibration of the model was made from data from a period of eleven weeks and a validation was made from data that differed as much as possible from the calibration data. Then the model was used to find out in what way an increase in production to 480 000 annual tons should affect the discharge of organic oxygen consumption substances. Results from the model indicates that the goals for the total COD-discharge will be hard to achieve with an increase in production to 480 000 annual tons. Despite the fact that production of TCF-pulp generates more COD than ECF-production the total discharge of COD is lower at TCF-production. The reason is that easier degradable COD is generated in TCF-bleaching. One of the major problems is that the torrent of water that is bypassed the biological treatment plant contains a large amount of COD and the efficiency of the treatment plant must be very high if the goals for the total COD-discharge shouldn’t be exceeded. / Det här examensarbetet gjordes för Södra Cell på Mörrums Bruk i Blekinge. Arbetet bestod i att göra en modell i simuleringsprogrammet Extend över nedbrytningen och massbalansen av organiska syreförbrukande ämnen, mätt som COD (Chemical Oxygen Demand), i den nybyggda biologiska reningsanläggningen på bruket. Mörrums bruk är en sulfatmassafabrik som producerar både TCF- (Totally Chlorine Free) och ECF- (Elementary Chlorine Free) massa för avsalu. De olika blekningsmetoderna påverkar sammansättningen på avloppsvattnet och därmed också den biologiska reningsanläggningens reduktion av COD. I modellen som utvecklades delades inkommande COD i obehandlat vatten upp i fem olika COD-fraktioner: löst lättnedbrytbart (SS), löst svårnedbrytbart (SR), löst inert (SI), partikulärt inert (XI) och partikulärt nedbrytbart COD i form av biomassa (XB). För att bygga modellen användes FlowMac™ som utgångspunkt. FlowMac™ är en biblioteksmodul i Extend avpassad för pappersbruk. En del block behövde bara modifieras medan andra block, t.ex. sedimenteringen och bioblocken, fick byggas till. Modellen kalibrerades med medelvärden från en elvaveckorsperiod och en validering gjordes med data från några veckor med mer extrema värden på inkommande vatten. Med modellen gjordes en simulering för att undersöka vad en produktionsökning till 480 000 årston skulle innebära med avseende på utsläppen av organiska syreförbrukande ämnen. Resultat från modellen tyder på att det vid en ökning av produktionen till 480 000 årston blir svårt att nå de uppställda totala utsläppsmålen för COD. Vid produktion av TCF-massa bildas mer COD men utsläppsmängderna är lägre än vid ECF-produktion. Anledningen är att den COD som bildas ut vid TCF-blekning innehåller en större mängd lättnedbrytbart COD. En bidragande orsak till att det blir svårt att hålla utsläppsmålen för COD är att de flöden som leds förbi reningsanläggningen innehåller mycket COD vilket gör att verkningsgraden över reningsanläggningen måste vara hög för att klara målen för totala COD-utsläppet.

The authors of this paper will try to identify what different pressure factors have an influence over the Swedish mechanical pulp and paper industry. Moreover, the authors of this paper will try to identify whether different levels of environmental commitment can be identified within the organization. The results show that all of the pressure factors that were identified in the case study, except for regulations and social pressure, are influenced by economic benefits and, therefore, a reactive stance is almost always preferred by the firm when there is a negative correlation between economic performance and environmental performance. Results also indicate a gap in the internal communication of the organization. This is not related to the topic of this paper but might be useful information for the company used in the case study.

Freshwater availability, allocation and quality are increasingly becoming a concern in Canada. Canada’s apparent availability of abundant freshwater is not what it was thought to be. With increasing competition for water sources and inadequate management systems water use and management approaches are being re-examined. While urban and municipal water uses are highly studied, Canadian industrial water use is not. Despite that industrial water use is understudied, the Canadian pulp and paper industry is a major user of water and contributes to quality water issues where mills are located. This thesis is divided into two equally important parts. First, this research seeks to understand the influences and prevailing conditions on the decision-making framework of pulp and paper mills. Second, it seeks to understand how the prevailing conditions affect the applicability of the water soft-path concept in the pulp and paper industry. It will contribute to the literature of Canadian industrial water management. This research specifically examines the applicability of the water soft-path concept under the stresses and realities of the systems of influence identified as market forces, policy and regulation, and technology faced by the Canadian pulp and paper industry. Corporate culture was an implicitly common thread that ran through these systems of influence. A variety of methods were used in this study including, a literature review conducted by themes, surveys, interviews, analysis of archival data and backcasting were used as the methodological approaches. The literature review was conducted by themes of water management, technology, market forces, regulation and corporate culture. Surveys were conducted to gain water use data from specific mills but a low response rate required a widening of the research boundaries. Interviews were conducted with government officials, industry representatives, and environmental non-governmental organizations. The interviews contributed to the boundary setting and understanding of the influences that impact decision-making for industry. The analysis of archival data was to better understand how water use in pulp and paper mills has changed through the years. Understandably the systems of influence (market forces, policy and regulation, and technology) work independently and together to create a complex environment in which decisions on water use in pulp and paper mills are made. The complexity of the decision-making framework is great and the barriers to water soft-path application difficult. Market forces are less capable of addressing environmental externalities such as water. Regulation and policy has yet to address water use in industry. Technology does provide an important opportunity for efficient water use and application of the pulp and paper industry. Ultimately, the Canadian pulp and paper industry is in a redefining moment where opportunity exists to create a new direction and approach to water use in the Canadian pulp and paper industry.

The overall objective of the research conducted and described in this thesis was to develop an environmentally relevant bioassay to assess the effects of complex effluents on a sentinel fish species. A short-term fathead minnow (FHM) reproductive bioassay was utilized to assess the effects of industrial effluents on multiple levels of biological organization (sub-organismal to population endpoints). The FHM bioassay was tested in both lab and on-site investigations using an artificial stream system. The incorporation of trophic-transfer into the bioassay was also developed to quantify the importance of contaminated food as a source of exposure. This work was conducted in two key phases. Phase I focused on testing and developing the FHM bioassay, in the lab and on-site with pulp mill effluent (PME), to firstly document response patterns and, secondly, to conduct an investigation of cause study. Phase II focused on developing the trophic-transfer system to document responses to metal mine effluent (MME) in the lab and on-site in an artificial stream system. Development of the trophic-transfer system was also conducted during this phase to compare responses to standard water-only exposures. <p>In Phase I, exposure to PME in both the lab and field studies resulted in disruptions in egg production and spawning events. By focusing on identifying response patterns I was able to determine that the effects observed were indicative of an estrogenic response. I was also able to identify a process stream that was the potential cause of responses observed after exposure to final effluent. Isolation of this process stream will assist the mill in developing approaches for future mitigation. The results from this research will also provide additional data for the environmental effects monitoring (EEM) program for pulp and paper and investigation of cause studies on a national basis. <p> In Phase II, in both the field and laboratory investigations, significant decreases in reproductive output (egg production and spawning events) were observed in the water-only system exposures. Significant decreases in hatching success and increases in deformities were observed in the trophic-transfer system only, suggesting that the combination of both food and water was important in assessing the effects on the F1 generation. Overall, the responses in the trophic-transfer system were not comparable between the lab and field studies. In the lab study, significant decreases in reproductive output occurred, compared to the field study where significant increases in egg production and spawning events occurred. In addition, the effects on the F1 generation in the field study were not as severe as those observed in the lab investigation. It was concluded that the presence of reference water and the environment within the trophic-transfer system were responsible for this reduction in toxicity. <p> Phases I and II of this research have made significant contributions to artificial stream development within Canada for the assessment of industrial effluents and their effects on aquatic biota. The results from these studies have also demonstrated that environmentally relevant testing is essential if we are to accurately assess effects on aquatic biota. Future development and application of this bioassay should be towards developing a standardized approach for not only assessing the effects of industrial effluents in a comparative manner, but also in investigation of cause studies.

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