The pulp and paper mill requires a lot of water during the production. Stora Enso Skoghall requires about 33m3 of water for 2204 lb produced carbon or paper. Before the wastewater returns to the recipient, the water must be purified from organic material. Organic material is naturally found in wood, and if a high level of organic material is added to the recipient it will lead to deficiency of oxygen in lakes. In order to avoid deficiencies of oxygen in lakes, the wastewater must go through a biological treatment, Stora Ensos biological treatment is consisting a long-term aerated active sludge, LAS, which is similar to a large pond. During a period, Stora Enso Skoghall constructed a pre-treatment step fort their LAS which is a Moving Bed Biofilm Reactor, MBBR. Stora Enso has been struggling to aerate the wastewater in the LAS, which has affected the production of the industry badly. The purpose of building the MBBR is to facilitate the LAS, in order to deliver full production. The biological treatment requires a lot of energy to operate the aeration system, about 50 percent of the total energy demand for a treatment plant goes to the biological treatment.   The purpose of this study is to examine the impact on the LAS if a MBBR-process is connected as a pre-treatment step. The aim of this study is to examine how the new biological treatment effects the energy demand considering aeration, compared to before the MBBR was connected. Wastewater samples were collected at Stora Enso Skoghall and taken to a laboratory at Karlstads University for analysis and tests. The wastewater samples have been studied regarding its content of TOC and how it affects the possibility of aerating the water. The a- and b-values, and as well the theoretical oxygen demand, were experimentally determined in cylinder aerators that contains 30 liters. The energy use for aeration of the MBBR and the LAS has been estimated. In order to compare if the new biological treatment effects the ability of purification in the existing LAS and if the energy demand changes, wastewater samples were taken before and after the MBBR was connected.   The result of this study shows that the MBBR has a positive impact on the existing LAS at Stora Enso Skoghall. There is a higher reduction of COD and the oxygen uptake capacity is better in the LAS, compared to before the MBBR was connected as a pre-treatment step. The total energy demand has increased with 58 percent, compared to the results before the MBBR were connected. The wastewater from the CTMP production contains high levels of TOC. It contains high levels of surfactants and high ionic strength, which usually worsen the ability of aeration. The flow into the MBBR contains mainly wastewater from the CTMP and the aeration tests showed that only 1-6 percent of the oxygen dissolved in it. As a result, the estimated energy demand remains very high. In conclusion, with the new biological treatment system the industry can now deliver full production of pulp and cardboard, while the LAS gets enough oxygen to effectively purify the wastewater. The MBBR relives the LAS through reduce the right amount of COD so the LAS can aerate the wastewater more easily. Moreover, the total energy demand of the biological treatment has increased when it comes to aerate the wastewater due to the fact that the production of pulp and cardboard has increased with 46 percent.

Harmful algal blooms in surface water supply systems pose a threat to public health and are increasing in both frequency and geographical distribution. Cyanobacteria can contribute to taste and odor issues and potentially release harmful cyanotoxins into the water. Several treatment methods are currently employed to control these blooms, including physical separation and chemical pre-oxidation. However, existing oxidation options can be costly; increase the release of intracellular material causing the formation of disinfection byproducts; or disrupt coagulation and filtration processes. This study investigated ferrate (Fe(VI)) as an alternative to other oxidants by measuring its effect on algae cells. Fe(VI) has several advantages as an oxidant, including a high oxidation potential, a low potential for harmful disinfection byproduct production, and formation of Fe(III) - which can potentially be beneficial for downstream treatment processes. Bench scale studies were conducted with laboratory prepared waters containing the common cyanobacteria Microcystis aeruginosa to examine the interactions between Fe(VI) and algae. The effects of ferrate oxidation on algae were characterized by particle counts, UV254 absorbance, total organic carbon (TOC) and dissolved organic carbon (DOC), and total nitrogen. Ferrate decomposition was also monitored. Results showed that Fe(VI) lysed algal cells under some conditions, but further oxidation of released organic matter is possible at some doses. Additionally, some coagulation benefits were observed through an overall decrease in total particle counts and an increase in particle sizes. In general, the results indicate that Fe(VI) could be a possible alternative to other oxidants for water utilities during harmful algal blooms; however, the final fate of resulting organic matter and the potential for disinfection byproduct formation should be further studied.

No description available.

Graphene Oxide (GO) has emerged within the last decade as a next generation material for water treatment. Fabrication of graphene oxide membranes has been limited in scale and application due to repulsive hydration forces causing GO layers to electrostatically separate. In this study, chitosan is utilized to increase GO stability in the wet state through interactions with the negatively charged GO sheets (CSGO). This simple aqueous self-assembly allows scalable fabrication and enhanced stability for membrane applications in crosslow. The CSGO membrane’s performance was tested in a crosslow reactor and challenged with methylene blue at concentrations ranging from 1 to 100 ppm at 345 kPa with fluxes ranging from 1 to 4.5 L/(m2 hr) with 100% removal by physical rejection. This work demonstrates that the CSGO composite matrix is a potential alternative to traditional polymeric membranes for water treatment using a renewable biopolymer and minimal chemical input.

Detta självständiga arbete utfördes på kraftvärmeanläggningen Affärsverken AB i Karlskrona med syfte att minska stadens vattenförbrukning, minimera utsläpp i naturen och bidra till globala miljömål. Se bilagor (7–10) för mer information.Projektet omfattade flera perspektiv, inklusive tekniker för att rena rökgaskondensat och de ekonomiska aspekterna av ett sådant projekt. Sammanfattningsvis syftar projektet till att förbättra effektiviteten och hållbarheten i kraftvärmeverket. Studiebesöket på kraftvärmeverket i Karlskrona har gett information om flödet av kommunalt vatten och rökgaskondensat mängden som används för att bestämma återvinningen av vatten och mängden rökgaskondensat som behövs. Detta kommer att användas för att utvärdera teknikerna för att rena rökgaskondensatet och de ekonomiska aspekterna av projektet.Målet med projektet var att minska stadens vattenkonsumtion på kraftvärmeverket genom att använda rökgaskondensat istället för stadsvatten. Detta minskar kostnaden för råvatten och bidrar till att uppnå globala miljömål. Konstruktion och installation kan kombineras med befintliga anläggningar, utrustning och ekonomiska faktorer som tas i beaktning vid valet av lösning. En hållbar och kostnadseffektiv lösning bör väljas för att minska stadens vattenkonsumtion utan att påverka produktiviteten. / This independent project was conducted at the combined heat and powerplant (Affärsverken AB) in Karlskrona with the aim of reducing city waterconsumption, minimizing emissions into the environment, and contributingto global environmental goals, see appendix (7-10). The project included several perspectives, including technologies for cleaning flue gas condensateand the economic aspects of such a project. In summary, the project aimed toimprove the efficiency and sustainability of the combined heat and powerplant.The study visit to the combined heat and power plant in Karlskrona has provided information on the flow of municipal water and the amount of flue gascondensate used to determine the recovery of water and the amount of fluegas condensate needed. This will be used to evaluate the technologies forcleaning the flue gas condensate and the economic aspects of the project.The conclusion of the project was to be able to reduce city water consumption at cogeneration plants by using flue gas condensate instead of city water.This reduces the cost of city water and contributes to achieving environmental global goals. Construction and installation can be combined with existingfacilities and equipment, and economic factors should be taken into accountwhen choosing a solution. Sustainable and cost-effective solution should bechosen to reduce city water consumption without affecting productivity.

Access to clean water is essential for human health and dignity. The increasingly rapid population growth, combined with the emergence of resistant chemical compounds and more concentrated toxic residues in the effluent streams of treatment plants, point towards a decline in freshwater resources resulting in a global water crisis in the next decades. Current wastewater treatment plants rely on Advanced Oxidation Processes (AOPs) for the tertiary (or advanced) step of the treatment. Photocatalysis is one of such processes, by which semiconductors are exposed to radiation of specific wavelengths (traditionally UV) to generate Reactive Oxygen Species (ROS) that can degrade organic molecules through a chain of radical oxidation reactions. Anatase titania (TiO2) has been used for many decades as a photocatalyst. Its electronic band structure has a band gap of 3.2 eV, requiring radiation in the UV range to trigger its photocatalytic properties. One way to reduce the band gap energy and shift the absorption peak wavelength to the visible part of the spectrum (thus reducing operation costs) is by doping the photocatalyst particles with transition metal atoms. Iron (III) is a great candidate due to the placement of its conduction/valence bands within titania’s band gap, its atomic radius similar to titanium (IV) and its variety of oxidation states. However, iron-doped anatase titania synthesized by ordinary sol-gel methods shows a photodegradation efficiency that is much lower than undoped anatase. Previous studies have shown that this is caused by an inconspicuous iron oxide layer on the surface of the catalyst particle, forming a physical barrier to the mobility of charge carriers that trigger the formation of ROS radicals. Small changes to the synthesis protocol, namely slowing down the hydrolysis of the Ti precursor by lowering the solution’s pH and acid-washing the final product, have been shown to result in particles that are photoactive under visible radiation and boast an unobstructed reactive surface. In this work, the novel Fe-TiO2 photocatalyst is studied and characterized in terms of its particle size distribution, inner structure and composition using electron microscopy techniques. It is important to know the particle size profile arising from this novel synthetic method, as the presence of nanoparticles could pose a health risk whereas an abundance of oversized particles is undesirable from the perspective of chemical reaction engineering (low surface-to-volume ratio). Inner structure/composition analyses could reveal whether the iron content inside the photocatalyst segregates into iron oxides, which would hinder reaction rates by behaving as a recombination center for charge carriers. As well, gathering more information about the inner structure of the catalyst (such as degree of crystallinity) is desirable as that could help fine-tune the synthesis protocol in order to obtain optimal photocatalytic activity. The particle size distribution studies using scanning electron microscopy revealed that the catalyst samples contain a significant fraction of nanoparticles (31.55% smaller than 100 nm), even though those particles represent a very small fraction of total sample volume (0.00015%) and reactive area (0.03%). Moreover, oversized particles (bigger than 5 m) account for the biggest fraction of sample volume and reactive surface. It was suggested that the size distribution of the catalyst be shifted to intermediate particle sizes by introducing additional grinding and separation steps into the synthesis protocol. The inner structure studies were carried using a combination of scanning, transmission and scanning-transmission electron microscopy, as well as spectroscopy methods such as EDX and EELS to map composition. It was found that the original anatase lattice structure remained unchanged in terms of interplanar spacings and crystallographic orientations, indicating that the addition of iron impurities at the small concentrations used here (0.5at%) did not result in discernible changes to the lattice. The monocrystalline units of Fe-TiO2 (termed crystallites) often appear to be bound together by amorphous material. No segregation of Fe was observed inside the particles at this concentration, as shown by the apparent homogenous composition of the catalyst across crystalline and amorphous regions. The external iron oxide contamination layer observed in previous studies was theorized to form during the later steps of the sol-gel process due to the precipitation of the iron content in solution that failed to be incorporated into the TiO2 gel network. More in-depth studies must be carried to assess whether preferential segregation of iron within the catalyst could occur at higher dopant concentrations. / Graduate

<p> Although both steady state and dynamic simulation studies of the activated sludge process are available, the data bases employed have traditionally been: derived from bench scale studies, derived from historical monitoring data, synthetic based on mathematical functions. Actual plant operating data, if available, would reflect full scale operation and would provide a much better data base to judge existing or future process models. This study was designed to provide a more comprehensive data base than presently existed on a full scale municipal activated sludge system. Both flow and component concentrations were continuously measured on two hour intervals for two periods of 10 days and 5 days duration. Streams sampled included the plant influent, the primary clarifier effluent, the aeration tank effluent, the secondary clarifier effluent, the activated sludge recycle and the waste sludge line. Based on total nitrogen and total phosphorus, the data were examined for mass flow closure around the aeration tank. A time dependent mixing model based on two unequal volume stirred tank reactors in series was found to adequately describe the observed variation in aeration tank input-output data. The measured aeration tank inflow and outflow was corrected to give a hydraulic balance using a statistical procedure which generates flow corrections based on expected measurement error. The resulting total nitrogen and total phosphorus material balances were found to improve based on a reduction of the residual sum of squares.</p> / Thesis / Master of Engineering (MEngr)

En kartläggning av vattenåtgång för kraftvärmeverket Torsvik visar att en självförsörjning av råvatten inte är möjlig genom att endast nyttja återcirkulation av renat rökgaskondensat. Att helt utesluta användandet stadsvatten som råvatten för att säkerställa spädvattenbehovet till pannorna är därför ej möjligt, men med hjälp av utökad rening och återcirkulation kan en resurseffektivisering ske på anläggningen. Resultatet visar på att en nyinvestering av lämplig teknik så som UFRO eller likvärdigt för kondensatrening måste ersätta den befintliga flockteknikensom idag används för avfallspannan på KVVT1, för att återcirkulation av kondensat skall vara ett möjligt alternativ för detta block. Vidare finns kvarvarande problematik med otillräckligt flöde av rökgaskondensat hos detta block för att bli självförsörjande av spädvatten. Möjligheterna för KVVT2 att bli självförsörjande är dock desto bättre där ett högre flöde av rökgaskondensat uppnås. För detta block krävs då en uppskalning av den befintliga rökgaskondensatreningen (UF/RO), då det inte täcker hela flödet i dagsläget.Referensanläggningar runt om i Sverige visar att det är möjligt att genomföra ett sådant projekt. Vidare finns det direktiv från EU genom BAT slutsatserna samt nationella bidrag att söka för projekt inom området för att nå de mål som är uppsatta globalt i och med Agenda30 åtagandet. Tidigare studier inom området påvisar att den tekniska utrustning som finns för området är välfungerande och att det finns mer än en fungerande lösning. Dock visar de även på att en anläggningsspecifik analys måste göras då de olika parametrarna varierar hos de olika anläggningarna där det lyfts fram att en pilotanläggning kan vara ett sätt att skära ner tiden för att få parametrarna att fungera korrekt på där flera anläggningar tagit mer än två år att bli driftsatta efter installation. Även Miljötillstånden varierar för de olika anläggningarna och det finns därmed ingen universallösning. Denna rapport sammanställer kraftvärmeverket Torsviks förutsättningar samt ställer dessa mot befintliga metoder hos liknande kraftvärmeverk med en behovsanalys genom kartering av råvattenflöden. Genom att ha kartlagt befintliga flödesmätare på Torsvik och trend analyserat dess data i anläggningens styrsystem har vi kommit fram till dess behov av råvatten för de olika processerna. Med hjälp av intervjuer och interna utredningar har vi skapat en tydligare bild av anläggningens vattenflöden samt gett rekommendationer av lämpliga metoder för att rena rökgaskondensatet för att minska vatteninköpet från stadsnätet. / A survey of water usage for the Torsvik power cogeneration plant showsthat self-sufficiency in raw water is not possible through solely recycling purifiedflue gas condensate. Completely excluding the use of municipal water as raw waterto meet the make-up water demand for the boilers is therefore not possible, but withthe help of enhanced purification and recycling, resource efficiency can be achievedat the facility. The results indicate that a new investment in appropriate technologysuch as UF-RO or equivalent for condensate treatment must replace the existingflocculation technology used for the waste boiler at KVVT1, in order for condensaterecycling to be a feasible alternative for this block. Furthermore, there is aremaining issue of insufficient flow of flue gas condensate for this block to achieveself-sufficiency. However, the possibilities for KVVT2 to become self-sufficient arebetter, with a higher flow of flue gas condensate. For this block, an upscaling of theexisting flue gas condensate treatment on block 2 is required as it does not meet thedemand.Reference facilities across Sweden demonstrate the feasibility ofimplementation. Furthermore, there are directives from the EU through BATconclusions, as well as national grants available for projects in this field to achievethe goals set globally with the Agenda30 commitment. Previous studies in the fielddemonstrate that the technical equipment available for this area is functioning welland that there is more than one viable solution. However, they also highlight theneed for site-specific analysis as the different parameters vary among differentfacilities, where it is emphasized that a pilot plant can be a way to reduce the time ittakes for the parameters to function correctly, as several facilities have taken morethan two years to become operational after installation. Environmental permits alsovary for different facilities, thus there is no universal solution.Therefore, this report compiles the conditions of the Torsvik powercogeneration plant and compares them with existing methods at similar powercogeneration plants. By mapping the existing flow meters at Torsvik and trendingthe data in the facility's control system, we have determined its raw waterrequirements for the different processes. Interviews and internal investigations havehelped us create a clearer picture of the facility's water flow.

This master thesis explores the possibility to selectively detect sewage intrusion indrinking water with a chemical sensor, the so called electronic tongue. Previouswork in collaboration between Linköping University and Tekniska verken has showna possibility to detect contaminants using the sensors ability to measure currentchanges due to electrochemical properties of the contaminants. This report presentstwo developed algorithms that can detect and alarm if sewage enters the drinkingwater. The algorithms performance is analyzed based on reaction time, stability,detection limit and selectivity. The results indicate that the implementation of thesensor and the algorithm will contribute to real-time monitoring of drinking waterquality and, with it, increase safety for society’s health. Parts of the practical development of these algorithms will be kept confidential in this report for intellectualproperty reasons and the possibility of further development of the system.

Increasing concentrations of pharmaceutical compounds and their metabolites in aquatic environment threatens both aquatic species and human health. Many pharmaceuticals are persistent in the environment and resistant to conventional water treatment; hence, alternate treatment techniques are required to remove these compounds from water. Aqueous phase electrical discharge has been demonstrated to successfully remove a range of pharmaceutical compounds from water. This technique is characterized by the simultaneous generation of highly reactive species and physical effects within the aqueous solution to be treated. The present study investigates and optimizes the efficacy of pulsed corona discharges generated in water for the treatment of carbamazepine (CBZ) in a relatively clean water matrix by varying the solution pH, solution conductivity, gas type injected, and gas flow rate injected. A point-to-plane reactor configuration was employed to produce plasma channel- streamers. In this geometry, the electrical discharges were produced directly within the aqueous phase to be treated by charging a 1nF pulse forming capacitor using a high voltage (25 KV) DC power supply through 10 MΩ resistor to generate discharges within the water at a 30 HZ pulse repetition rate. Solution pH, solution conductivity, gas type, and gas flow rate were optimized to maximize the removal efficacy of CBZ removal by pulsed corona at the laboratory scale. The CBZ degradation rate (concentration decrease over time) was monitored using LC/MS/MS, with overall degradation ranging from 14-94% depending on the experimental conditions. The results demonstrate that higher CBZ removal efficiency is achieved under lower pH and conductivity conditions. Moreover, enhanced degradation efficiency is obtained when gas, and particularly oxygen, is bubbled through the high voltage hollow electrode, especially at higher flow rates. / Thesis / Master of Applied Science (MASc) / Pharmaceuticals are being released into the environment at an increasing rate due to population growth and a rising dependence on these compounds. Pharmaceuticals are resistant to many common water treatment methods; however, electrical discharge generated within the water to be treated (pulsed corona discharge) is an emerging water treatment technology that has been shown to successfully treat many pharmaceuticals. In the present work, pulsed corona discharge has been used to treat carbamazepine present in a relatively clean water matrix. Removal was maximized by optimizing the solution pH, solution conductivity, type of gas bubbled through the electrode, and gas flow rate. The best removal was achieved in solutions with lower pH and conductivities where oxygen was bubbled through the electrode at a relatively high rate.