Made available in DSpace on 2016-04-18T21:35:57Z (GMT). No. of bitstreams: 2 Graziella Ferecini Bueno Amaral1.pdf: 4073691 bytes, checksum: 8ff4dce433de3d6c54c6320e248c3e74 (MD5) Graziella Ferecini Bueno Amaral2.pdf: 2731324 bytes, checksum: 8a0dac7da8171451384cd27ab251102c (MD5) Previous issue date: 2011-03-17 / Fundo Mackenzie de Pesquisa / In this study it was studied the physical-mechanical properties of elastomers based on styrenebutadiene rubber (SBR) with the addition of barite, for application of these compounds in protecting in the shielding against radiation X, for the substitution of aprons form based on elastomer fillered with lead in ergonomic and economically advantageous conditions. Elastomeric compounds were studied with different barite concentrations [50, 75, 100, 125 and 150 phr (parts for hundred of rubber)]. The studied properties were: tensile strength, tensile modulus, tear strength, permanent deformation in compression, hardness, absorption of fluid, resilience, measure of rheology, morphological analysis and characterization of attenuating materials to radiation X. Results showed that all compositions exhibit good dispersion of the filler in the matrix. It was observed that with the increase barite concentration there is an increase in hardness beyond not causing significant alteration in the tensile strenght, in the elasticity, as well as in the resistance to the tearing of the material. / Neste trabalho foram estudadas as propriedades físico-mecânicas de elastômeros a base de borracha de estireno-butadieno (SBR) com a adição de barita, para aplicação destes compostos na proteção de blindagem contra a radiação X, para a substituição de aventais a base de elastômeros carregados com chumbo em condições ergonômicas e economicamente vantajosas. Foram estudados compostos elastoméricos com diferentes concentrações de barita [50, 75, 100, 125 e 150 phr (partes por cem de borracha)]. Entre as propriedades estudadas destacam-se: resistência à tração, módulo sob tração, resistência ao rasgo, deformação permanente à compressão, dureza, absorção de fluido, resiliência, medida de reologia, análise morfológica e caracterização de materiais atenuadores à radiação X. Os resultados mostraram que todas as composições apresentam uma boa dispersão da carga na matriz. Observou-se que com o aumento da concentração de barita há um aumento na dureza além de não causar alteração significativa na resistência à tração, na elasticidade, bem como na resistência ao rasgamento do material.

Avloppsreningsverket i Forsmark renar vattnet med aktivt slam i en satsvis biologisk rening (SBR) reaktor samt med våtmarker. Våtmarkerna består av fyra pulskärr och en damm. Pulskärren är utformade som bassänger fyllda med grus som filtermaterial där ytan är bevuxen. Pulskärren beskickas satsvis med 60 m^3 vatten när någon av SBR-reaktorerna töms, vattnet rinner då ut över ytan samtidigt som det perkolerar ner i bädden. När SBR-reaktorn har tömts är hela pulskärret mättat. Tömningen av pulskärret sker genom ett dränerande gruslager i botten och sedan flödar vattnet vidare ut genom ett ställbart dräneringsrör till slutdammen. Pulskärrens uppgift är att stoppa partiklar och att fungera som ett nitrifierande steg ifall verket i framtiden skulle få ökade reningskrav. I detta arbete har pulskärrens funktion som nitrifierare av ammonium undersökts. Detta genom att sammanställa befintliga driftdata från reningsverket, fältstudier samt en litteraturgenomgång. Målet med fältstudien var att mäta halten ammonium, nitrat och totalkväve i vattnet som gick in och ut ur pulskärret för att se hur halterna ändrades. Dessutom mättes temperatur, syrehalt, pH och konduktivitet. Provtagningen genomfördes på två pulskärr med tömningstiderna två respektive fyra timmar. Resultaten visade att ammoniumhalterna halveras i pulskärren. Inkommande ammonium till pulskärren var cirka 3 mg/l under studien men om ammoniumkoncentrationen skulle öka kommer nitrifikationen antagligen ske i liknande utsträckning. Detta då liknande system påvisat sådana resultat. Ökad tömningstid för pulskärren medför ökad nitrifikation, pulskärren bör därför ställas om så att tömning sker under cirka fyra timmar. För att hitta en optimal tömningstid bör vidare undersökningar göras. Forsmarks avloppsreningsverk möter de reningskrav som ställts med marginal. Trots att detta inte var syftet, avskiljs 80 % av inkommande kväve och det kunde konstateras att den största kväveavskiljningen sker i SBR-reaktorn. Kvävereduktionen har uppstått då verket haft låg belastning samtidigt som mycket syre tillsatts till processen. Då rening genom pulskärr sker efter att vattnet passerat genom SBR-reaktorerna borde luftningen kunna minskas för att istället utnyttja pulskärrens nitrifierande egenskaper. Svensk kärnbränslehantering AB har planer på att leda lakvatten till reningsverket för att avskilja kväverester, skulle detta ske kommer flödena över pulskärren att öka. Att den hydrauliska belastningen ökar borde inte utgöra några problem då flödena troligen inte kommer överstiga pulskärrens kapacitetsgränser. I extrema fall kan tömningstiden på pulskärren minskas. / Forsmark wastewater treatment plant treats wastewater using an active sludge process in sequencing batch reactors (SBR:s) and followed by constructed wetlands. The wetlands consist of four intermittent loaded soil filters (ILS:s) and a pond. The ILS:s is designed as pools filled with filter material and with a plant-grown surface. One of the ILS:s fills up with water when one of the SBR reactors is emptied. The water flows out over the surface as it percolates into the bed. When the SBR reactor is emptied, the entire ILS becomes saturated. The ILS then drains through a drainage gravel layer at the bottom and further through an adjustable drainage pipe into the dam. The purpose of the ILS:s is to work as extra filter for removal of the remaining particles and escaping sludge. They have also been thought to act as a nitrifying step if the plant would have tougher cleaning requirements in the future. In this report, the function of the ILS:s as nitrifying steps was investigated by compiling existing operating data from the treatment plant, with conducted field studies and through a literature review. The field study aimed at measuring ammonium, nitrate and total nitrogen in the water at the entering and the outlet in the ILS to see how the different nitrogen concentrations was affected. Temperature, oxygen, pH and electricalconductivity were also measured. The sampling was done on two ILS with different drainage time, two and four hours. The results showed that the ILS:s nitrifies the incoming water with an average efficiency of 50 % depending on the ammonium contentration in the incoming water. An increased drainage time for the ILS seamed to result in better nitrification. Therefore, the ILS:s should be changed to drain for at least four hours. Should the ammonium concentration increase above 3 mg/l the nitrification rate would probably be about the same. Similar systems such as have shown similar nitrification removal but with higher ammonia concentrations. Forsmarks wastewater treatment plant meets the purification requirements imposed on the plant with margin. It is remarkable that, without planning for any nitrogen removal, the removal is about 80 % of incoming nitrogen, most of which is removed in the SBR reactor. Svensk Kärnbränslehantering AB plans to lead leachate to the treatment plant for nitrogen removal. If this plan is fulfilled, the flows through the ILS will increase. This should not be a problem as the total flow trought the ILS will not exceed the capacity limits of the ILS. In case of high flows, the emptying time of the ILS:s can be reduced.

<p>If not purified leachate from landfills would cause damages on the environment. At most landfills in Sweden local treatment of leachate is achieved, at the rest the leachate is transported to sewertreatment. While no comprehensive legal provisions for discharge exist in Sweden there is a difference in discharges between the installations for landfill. If no comprehensive legal provisions is produced guidance must improve.</p><p>Treatment of leachate and self monitoring system at fifteen installations in Sweden has been studied and compared. A study of literature about different treatment solutions has also been performed. Practical information about the landfills has been gathered through visits. Processes of treatment described in literature correspond to measures. Variations exists between the self monitoring systems at the installations both between parameters for analyses, how often controls take place and were testpoints are situated.</p><p>Knowledge of reactions and techniques for treatment of compounds common in leachate exist. Further research about compounds whose effect we do not know for certain must be achieved.</p> / <p>Lakvattenrening och egenkontrollprogram vid femton deponier i Sverige har studerats och jämförts. En litteraturstudie angående olika reningstekniker har även utförts. Information om deponierna och reningsprocesserna har inhämtats via studiebesök och miljörapporter. Vid jämförelse av rening har olika processer studerats separat. Den beskrivning av processerna som finns i litteraturen stämmer väl med uppmätta resultat. Exempel på detta är ammoniumhalter som reduceras i luftad damm, halter totalkväve som minskar genom rening i Satsvis Biologisk Reaktorteknik och reducerad halt suspenderat material som inträffar vid rening genom markfilter. Egenkontrollprogrammen vid de olika deponierna varierar dels i avseende på vilka parametrar som kontrolleras och dels hur ofta kontroller utförs och var provpunkter är belägna.</p><p>För de vanligast förekommande ämnen som existerar i lakvatten finns kunskap om reaktioner och fungerande tekniker för rening. Problem uppstår för de ämnen vilkas reaktioner och förändringar man ej känner till. Farhågor finns dessutom att det i lakvatten finns föreningar vars existens och verkan vi ej känner till. På grund av detta krävs ytterligare forskning på lakvatten.</p>

<p>Sedan december 2003 har Kalmar läns slakteris (KLS) nya reningsverk varit i drift. Entreprenör för det nya reningsverket samt driftansvariga under det två första åren är Läckeby Water Group. Verket är av SBR-typ (Sekventiell Biologisk Rening) med biologisk kväverening och kemisk fällning av fosfor med hjälp av järnklorid. Från slakteriet leds avloppsvattnet genom en 2 km lång ledning ner till reningsanläggningen. Verket hade under 2004 problem med höga halter fosfor i utgående vatten, flertalet mekaniska haverier samt två perioder av slamsvällning. Slamsvällningen orsakades av filamentösa (trådformiga) bakterier, första gången av Thiothrix spp. och andra gången av Typ 021N. Syftet med examensarbetet var att finna orsaken till den senare slamsvällningen samt att söka förebyggande åtgärder mot Typ 021N. Examensarbetet utfördes genom litteraturstudier, laboratorieförsök, fullskaleförsök, genomgång av driftsdata samt mikroskopering av aktivt slam vid verket.</p><p>Utifrån litteraturstudier konstaterades att filamentösa bakterier kan gynnas under perioder av låga syrehalter samt av låg näringstillförsel eftersom dessa bakterier har en högre tillväxthastighet vid låga substratkoncentrationer än flockbildande bakterier. Specifikt för Typ 021N är att dessa har möjlighet att utnyttja reducerat svavel som energikälla samt gynnas vid tillgång på korta lättnedbrytbara kolföreningar. Laboratorieförsök visade inte entydigt att låga fosfor eller syrehalter gynnade de filamentösa bakterierna. Inverkan av FeCl3, Ecofloc, PAXXL60, NaOCl och H2O2 studerades under korttids laboratorieförsök och effekten utvärderades i mikroskop. I några fall hämmades filamenten men aldrig utan att även påverka övriga mikroorganismer negativt. PAX-XL60 hämmade filamentförkomsten mest och påverkade andra organismer förhållandevis lite. Tillsats av PAX i filamenthämmande och flockbildande syfte utfördes därefter i fullskala. Effekten av tidigare tillsatser av NaOCl och H2O2 i filamenthämmande syfte studerades och visade sig ha givit varierande resultat. NaOCl visade sig effektivt bekämpa filamentösa bakterier i processen då inblandning skedde under rätt förutsättningar.</p><p>Processdata för våren 2004 jämfördes med data från en period under hösten, vilken följdes av en slamsvällning. Perioderna visade stora skillnader m.a.p. syrehalt, temperatur, dosering av järnklorid och organisk belastning. En on-line mätning i inkommande vatten visade på mycket höga halter av svavelväte. Svavelväte bildas under anaeroba förhållanden t.ex. i stillastående avloppsvatten. Orsaker till slamsvällningen i september-oktober 2004 tros vara höga halter av svavelväte, perioder med låga syrehalter, höga vattentemperaturer samt tillgång på lättnedbrytbart organiskt material. Svavelvätet kan förslagsvis elimineras genom en tidsstyrd dosering av CaNO3 i inkommande ledning. Noggrann övervakning av syre samt tillgång på syre måste garanteras i processen. Det inkommande vattnets mikroflora kan förändras genom installation av en aerob selektor för att gynna de flockformande bakterierna. För att sänka fosforhalterna i utgående vatten samt att inte riskera fosforbrist i processen har en tillfällig efterfällning med extra tillsats av FeCl3 och polymer installerats.</p> / <p>In December 2003 the new plant treating slaughterhouse wastewater from KLS was taken into operation. Läckeby Water Group was entrepreneur and responsible for the maintenance during the following two years. The treatment plant is of SBR-type and has biological nitrate removal and chemical precipitation of phosphate with iron chloride. The wastewater from the slaughterhouse passes a 2 km long pipeline before entering the treatment plant. During 2004, the plant had problems with high levels of phosphorous in the effluent, several mechanical problems and two occasions of sludge bulking caused by filamentous bacteria. The first incident was caused by Thiothrix spp. and the second by Type 021N. The aim with the thesis was to find causes for the latest period of sludge bulking as well as investigate preparatory actions against Type 021N. The thesis included literature studies, laboratory and full-scale tests, evaluation of prior process data and continuous microscopic analysis of the activated sludge at the plant.</p><p>The literature study showed that filamentous bacteria are favoured by low oxygen and low nutrient concentrations due to their possibly higher growth rate during low substrate concentrations. Type 021N, specifically, can use reduced sulphides as energy source and benefits from an excess of low molecular substrates. Laboratory experiments did not verify that the filamentous bacteria were favoured by low oxygen concentration or low phosphate levels. The effect of FeCl3, Ecofloc, PAX-XL60, NaOCl and H2O2 added to a bulking sludge was evaluated by microscopic analysis. No chemical was found to suppress the filamentous bacteria without also affecting the floc-forming bacteria negatively. PAX-XL60 showed the largest negative effects on filamentous bacteria and only a minor impact on other microorganisms. Full-scale tests with PAX were thereafter performed in order to suppress filamentous bacteria as well as flocculate particulate solids. The effect of earlier additions of NaOCl and H2O2 into the process gave varied results. NaOCl was efficient against filamentous bacteria when addition was made during correct circumstances.</p><p>Process data from two separate periods during 2004 was compared. One period was followed by good effluent values and another period by a sludge bulking period. Large differences between the two periods were seen in oxygen conditions, temperature, FeCl3 dosage and organic load. Measurements on influent wastewater showed high levels of hydrogen sulphide, which can be produced during anaerobe conditions i.e. in stagnant sewage pipes. Likely causes for the sludge bulking in September-October 2004 were high levels of hydrogen sulphide in the influent, periods of insufficient oxygen concentrations, high water temperatures and access to easy degradable substrate. The hydrogen sulphide can be eliminated through time-controlled dosage of CaNO3 in influent pipeline. Sufficient oxygen levels must be guaranteed in the process. The microbiological fauna in influent can be changed by installation of an aerobe selector to benefit floc-forming bacteria. To lower the phosphorous levels in effluent water and not risk phosphorous deficiency in the process a post-precipitation have been installed. The post-precipitation include extra dosage of FeCl3 and polymer and a drum screen to minimize suspended solids.</p>

Typical rubber compounds used to manufacture industrial products such as tyres, hoses, conveyor belts, acoustics, shock pads, and engine mountings contain up to eight classes of chemical additives· including curing agents, accelerators, activators, processing aids, and antidegradants. The cure systems in these articles often consists of primary and secondary accelerators, primary and secondary activators, and elemental sulphur. Recent legislation impacting upon the working environment, safety and health has imposed a considerable burden on the manufacturers of rubber compounds to meet various obligations. The selection of raw materials and manufacturing processes that do not harm the environment is of great importance. A novel technique for preparing rubber formulations using crosslinking nanofillers such as silanised precipitated silica has been developed in this research. The silica surfaces were pre-treated with bis[3-triethoxysilylpropyl-] tetrasulphane coupling agent (TESPT).· TESPT is a sulphur containing bifunctional organosilane which chemically adheres silica to rubber and also prevents silica from interfering with the reaction mechanism of sulphur-cure systems. The tetrasulphane groups of the TESPT are rubber reactive and react in the presence of accelerator at elevated temperatures, i.e.140 -260°C, with or without elemental sulphur being present, to form crossIinks in rubbers containing chemically active double bonds for example styrene-butadiene rubber (SBR) and polybutadiene rubber (BR) .. SBR and BR rubber compounds containing 60 phr of TESPT pre-treated silica nanofiller were prepared. The silica particles were fully dispersed in the rubber, which was cured primarily by using sulphur in TESPT. The reaction between the tetrasulphane groups of TESPT and the rubbers was optimised by incorporating different accelerators and activators in the rubber. The mechanical properties of the rubber vulcanisates such as hardness, tear strength, tensile strength, elongation at break, stored' energy density at break, abrasion resistance, modulus and cyclic fatigue life were increased significantly when the treated silica filler was added. The need for the accelerator and activator was dependent on the composition of the rubber. Interestingly, the rubbers were fully cured without the use of elemental sulphur, secondary accelerator and secondary activator. As a result, a substantial reduction in the use of the curing chemicals was achieved without compromising the important properties of rubber compounds which are essential for maintaining long life and good performance of industrial rubber products in service. This approach has also helped to improve health and safety within the workplace and minimise harm to the enviromnent.Furthermore, a significant cost saving was achieved after reducing the number of curing chemicals in the rubber.

L’objectif de cette étude est l’élaboration de nanocomposite à base d’un élastomère de styrène et de butadiène (SBR) par l’ajout d’une dispersion aqueuse (slurry) de nanocharges lamellaires de phosphate de zirconium en phase α (α-ZrP ou ZrP). Les travaux s’attardent d’abord sur le mélange entre le SBR à l’état fondu et le slurry de ZrP en absence de traitement de surface. Différents stratégies d’élaboration sont ensuite envisagées afin d’améliorer la dispersion (intercalation exfoliation) des feuillets de ZrP dans le matériau en couplant le traitement de surface du ZrP et les paramètres de mise en œuvre. Différents traitements de surface sont abordés avec l’utilisation d’un agent intercalant métallique (Na+), de deux intercalants alkylamines (propylamine, octadécylamine) et d’un agent d’exfoliation (hydroxyde de tétrabutylammonium). En parallèle, plusieurs procédés de mise en œuvre générant des écoulements complexes sont utilisés. La complémentarité entre la diffraction des rayons X (DRX), la microscopie électronique en transmission (MET) et la spectroscopie mécanique (DTMA) permet d’obtenir une analyse multi-échelle de l’état de dispersion du ZrP et de proposer des scénarii décrivant les mécanismes de dispersion en fonction des paramètres étudiés. Un effort important est apporté pour la compréhension de la relation structure à l’échelle nanoscopique et les propriétés macroscopiques du matériau. Une étude comparative est ensuite proposée entre les valeurs expérimentales de l’effet de renforcement des matériaux et les prédictions des modèles Krieger-Dougherty et Halpi-Tsai / This work focuses on the melt processing of nanocomposite materials obtained from a synthetic lamellar filler, α-zirconium phosphate (α-ZrP), dispersed within a synthetic rubber of the SBR type. The first step is the melt compounding using aqueous slurry of α-ZrP without any treatment. Following, several kinds of surface modifiers such as sodium cation, alkylamines and tetrabutylammonium hydroxide and different melt processing conditions are investigated to improve the level of dispersion of ZrP platelets into the matrix. X-ray diffraction, transmission electron microscopy and dynamical mechanical method are used as a multi-scale analysis to quantify the state of dispersion of the filler within the nanocomposite. Several mechanisms of dispersion are described depend on the surface modifying treatment and the melt processing parameters and the structure-properties relationship are studied. A comparison between the material reinforcement and two models of predictions, Krieger-Dougherty and Halpin-Tsai are discussed

L'objectif de cette étude est l'élaboration de nanocomposite à base d'un élastomère de styrène et de butadiène (SBR) par l'ajout d'une dispersion aqueuse (slurry) de nanocharges lamellaires de phosphate de zirconium en phase α (α-ZrP ou ZrP). Les travaux s'attardent d'abord sur le mélange entre le SBR à l'état fondu et le slurry de ZrP en absence de traitement de surface. Différents stratégies d'élaboration sont ensuite envisagées afin d'améliorer la dispersion (intercalation exfoliation) des feuillets de ZrP dans le matériau en couplant le traitement de surface du ZrP et les paramètres de mise en œuvre. Différents traitements de surface sont abordés avec l'utilisation d'un agent intercalant métallique (Na+), de deux intercalants alkylamines (propylamine, octadécylamine) et d'un agent d'exfoliation (hydroxyde de tétrabutylammonium). En parallèle, plusieurs procédés de mise en œuvre générant des écoulements complexes sont utilisés. La complémentarité entre la diffraction des rayons X (DRX), la microscopie électronique en transmission (MET) et la spectroscopie mécanique (DTMA) permet d'obtenir une analyse multi-échelle de l'état de dispersion du ZrP et de proposer des scénarii décrivant les mécanismes de dispersion en fonction des paramètres étudiés. Un effort important est apporté pour la compréhension de la relation structure à l'échelle nanoscopique et les propriétés macroscopiques du matériau. Une étude comparative est ensuite proposée entre les valeurs expérimentales de l'effet de renforcement des matériaux et les prédictions des modèles Krieger-Dougherty et Halpi-Tsai

Biological nutrient removal is used as an indicator of SBR performance at nine different SBRplants operated for a long period at low water temperatures (5 – 10oC). Typically needed aeratedSRT (Solids Residence Time) for complete nitrification is found to be in the range of 6 – 10 days.Biological phosphorus removal has been found to take place at 5oC. The specific nitrification and denitrification rates (g N/kg VSS/h) have been found to besubstantially higher than those found in design recommendations. At temperatures &lt; 10 oC thenitrification rates have been found up to 4 g Nox/kg VSS/h. It has also been possible to establish a relation between the COD/N ratio and the nitrificationrate, showing that the rate increases to high rates when the ratio decreases. Enhanced biological phosphorus removal has been demonstrated at two different plants even atlow water temperatures 5 – 7 oC. Efficient biological nitrogen removal and phosphorus removal has been demonstrated at bothlow water temperatures and in presence of very high Chromium concentrations in inlet water, upto 20 mg Cr/l. The plants operated with a short fill time in comparison with the total cycle time for the SBRprocess have all demonstrated good sludge settling properties, suggesting that the SBR processmay incorporate a good sludge selection performance. Once a flexible operation strategy has been installed (in most cases through PLC systems) it hasbeen possible to meet load variations to maintain good treatment results. This has been found tobe true for most of the plants included in the thesis. Finally, a modified way to assess the energy efficiency for the system is analysed and suggested.Instead of using the traditional ratio kWh/kg BODremoved the use of kWh/kg OCPremoved as a basisfor energy efficiency is used as a far more relevant efficiency measurement. / QC 20100803

La eliminación biológica de nitrógeno amoniacal se ha llevado a cabo, habitualmente, a través del proceso convencional de nitrificación-desnitrificación. Sin embargo, los lixiviados generados en los depósitos controlados de residuos sólidos urbanos contienen elevadas cantidades de amonio y bajas concentraciones de materia orgánica biodegradable, así como una elevada salinidad. En este caso, para reducir el elevado coste económico que supone aplicar los procesos convencionales en este tipo de efluentes es conveniente desarrollar sistemas alternativos. Uno de estos nuevos procesos biológicos se basa en el proceso anammox (acrónimo en inglés de anaerobic ammonium oxidation) previa nitritación parcial de amonio a nitrito. El proceso anammox es un proceso autotrófico que realiza la conversión de amonio y nitrito a nitrógeno gas bajo condiciones anaerobias. El menor consumo de oxígeno durante el proceso de nitritación parcial y la no necesidad de adicionar materia orgánica para desnitrificar representan un importante ahorro económico respecto a los tratamientos convencionales / Biological nitrogen removal has traditionally been performed by the conventional nitrification-denitrification process. Leachates generated in urban solid waste landfills are characterized by high ammonia concentration and low biodegradable organic matter content, as well as high salinity. In order to reduce the economic costs associated with the conventional process currently used for this kind of effluents, it is necessary to develop alternative treatment procedures. One of these alternative biological systems is the anammox (anaerobic ammonium oxidation) process, previous partial nitritation from ammonia to nitrite. It is an autotrophic process that converts ammonia and nitrite to dinitrogen gas under anaerobic conditions. When compared to conventional treatments, the combined partial nitritation and anammox processes have lower dissolved oxygen consumption for partial nitritation and organic matter is no longer needed for autotrophic denitrification.

Sedan december 2003 har Kalmar läns slakteris (KLS) nya reningsverk varit i drift. Entreprenör för det nya reningsverket samt driftansvariga under det två första åren är Läckeby Water Group. Verket är av SBR-typ (Sekventiell Biologisk Rening) med biologisk kväverening och kemisk fällning av fosfor med hjälp av järnklorid. Från slakteriet leds avloppsvattnet genom en 2 km lång ledning ner till reningsanläggningen. Verket hade under 2004 problem med höga halter fosfor i utgående vatten, flertalet mekaniska haverier samt två perioder av slamsvällning. Slamsvällningen orsakades av filamentösa (trådformiga) bakterier, första gången av Thiothrix spp. och andra gången av Typ 021N. Syftet med examensarbetet var att finna orsaken till den senare slamsvällningen samt att söka förebyggande åtgärder mot Typ 021N. Examensarbetet utfördes genom litteraturstudier, laboratorieförsök, fullskaleförsök, genomgång av driftsdata samt mikroskopering av aktivt slam vid verket. Utifrån litteraturstudier konstaterades att filamentösa bakterier kan gynnas under perioder av låga syrehalter samt av låg näringstillförsel eftersom dessa bakterier har en högre tillväxthastighet vid låga substratkoncentrationer än flockbildande bakterier. Specifikt för Typ 021N är att dessa har möjlighet att utnyttja reducerat svavel som energikälla samt gynnas vid tillgång på korta lättnedbrytbara kolföreningar. Laboratorieförsök visade inte entydigt att låga fosfor eller syrehalter gynnade de filamentösa bakterierna. Inverkan av FeCl3, Ecofloc, PAXXL60, NaOCl och H2O2 studerades under korttids laboratorieförsök och effekten utvärderades i mikroskop. I några fall hämmades filamenten men aldrig utan att även påverka övriga mikroorganismer negativt. PAX-XL60 hämmade filamentförkomsten mest och påverkade andra organismer förhållandevis lite. Tillsats av PAX i filamenthämmande och flockbildande syfte utfördes därefter i fullskala. Effekten av tidigare tillsatser av NaOCl och H2O2 i filamenthämmande syfte studerades och visade sig ha givit varierande resultat. NaOCl visade sig effektivt bekämpa filamentösa bakterier i processen då inblandning skedde under rätt förutsättningar. Processdata för våren 2004 jämfördes med data från en period under hösten, vilken följdes av en slamsvällning. Perioderna visade stora skillnader m.a.p. syrehalt, temperatur, dosering av järnklorid och organisk belastning. En on-line mätning i inkommande vatten visade på mycket höga halter av svavelväte. Svavelväte bildas under anaeroba förhållanden t.ex. i stillastående avloppsvatten. Orsaker till slamsvällningen i september-oktober 2004 tros vara höga halter av svavelväte, perioder med låga syrehalter, höga vattentemperaturer samt tillgång på lättnedbrytbart organiskt material. Svavelvätet kan förslagsvis elimineras genom en tidsstyrd dosering av CaNO3 i inkommande ledning. Noggrann övervakning av syre samt tillgång på syre måste garanteras i processen. Det inkommande vattnets mikroflora kan förändras genom installation av en aerob selektor för att gynna de flockformande bakterierna. För att sänka fosforhalterna i utgående vatten samt att inte riskera fosforbrist i processen har en tillfällig efterfällning med extra tillsats av FeCl3 och polymer installerats. / In December 2003 the new plant treating slaughterhouse wastewater from KLS was taken into operation. Läckeby Water Group was entrepreneur and responsible for the maintenance during the following two years. The treatment plant is of SBR-type and has biological nitrate removal and chemical precipitation of phosphate with iron chloride. The wastewater from the slaughterhouse passes a 2 km long pipeline before entering the treatment plant. During 2004, the plant had problems with high levels of phosphorous in the effluent, several mechanical problems and two occasions of sludge bulking caused by filamentous bacteria. The first incident was caused by Thiothrix spp. and the second by Type 021N. The aim with the thesis was to find causes for the latest period of sludge bulking as well as investigate preparatory actions against Type 021N. The thesis included literature studies, laboratory and full-scale tests, evaluation of prior process data and continuous microscopic analysis of the activated sludge at the plant. The literature study showed that filamentous bacteria are favoured by low oxygen and low nutrient concentrations due to their possibly higher growth rate during low substrate concentrations. Type 021N, specifically, can use reduced sulphides as energy source and benefits from an excess of low molecular substrates. Laboratory experiments did not verify that the filamentous bacteria were favoured by low oxygen concentration or low phosphate levels. The effect of FeCl3, Ecofloc, PAX-XL60, NaOCl and H2O2 added to a bulking sludge was evaluated by microscopic analysis. No chemical was found to suppress the filamentous bacteria without also affecting the floc-forming bacteria negatively. PAX-XL60 showed the largest negative effects on filamentous bacteria and only a minor impact on other microorganisms. Full-scale tests with PAX were thereafter performed in order to suppress filamentous bacteria as well as flocculate particulate solids. The effect of earlier additions of NaOCl and H2O2 into the process gave varied results. NaOCl was efficient against filamentous bacteria when addition was made during correct circumstances. Process data from two separate periods during 2004 was compared. One period was followed by good effluent values and another period by a sludge bulking period. Large differences between the two periods were seen in oxygen conditions, temperature, FeCl3 dosage and organic load. Measurements on influent wastewater showed high levels of hydrogen sulphide, which can be produced during anaerobe conditions i.e. in stagnant sewage pipes. Likely causes for the sludge bulking in September-October 2004 were high levels of hydrogen sulphide in the influent, periods of insufficient oxygen concentrations, high water temperatures and access to easy degradable substrate. The hydrogen sulphide can be eliminated through time-controlled dosage of CaNO3 in influent pipeline. Sufficient oxygen levels must be guaranteed in the process. The microbiological fauna in influent can be changed by installation of an aerobe selector to benefit floc-forming bacteria. To lower the phosphorous levels in effluent water and not risk phosphorous deficiency in the process a post-precipitation have been installed. The post-precipitation include extra dosage of FeCl3 and polymer and a drum screen to minimize suspended solids.