The key tool for tissue engineering is the scaffold that supports cells for new tissue growth. Materials used for creating scaffolds are based on polymeric materials, carbon nanofibers, ceramics, and metals and their alloys. In my thesis, I describe the synthesis and characterization of new biodegradable hydrogels containing biodegradable crosslinks and biodegradable nanofibrous materials intended for scaffolds for tissue engineering. I also describe the preparation of macroporous hydrogels intended for neural tissue healing. In the first portion of this thesis, I examine a hydrogel based on a pH- responsive crosslinker. This hydrogel is stable at basic and neutral pHs but is degradable at pH < 7.4. The degradation rate of this hydrogel can be tailored. This hydrogel can be utilized as an esophageal stent or as a targeted drug release system in the stomach. The second portion of this thesis focuses on a biodegradable hydrogel designed for neural tissue repair. This hydrogel is composed of copolymers of N-(2- hydroxypropyl)methacrylamide and a newly synthesized biodegradable crosslinker based on 6,6'-dithiodinicotinic acid. This hydrogel can be stored in a neutral environment without degradation. Its long-term storage capability is another great advantage for clinical applications. During storage,...

Charles University, Faculty of Pharmacy in Hradci Králové Department of: Pharmaceutical technology Consultants: Jana Kubačková, Ondřej Holas Student: Jáchym Vencl Title of Thesis: Optimization of polymeric nanoparticles separation and purification protocol Poly(lactic-co-glycolic) acid (PLGA) is one of the most successful polymeric molecule invented for biomedical use. PLGA's biggest advantage lies in its biodegradability and nontoxicityChyba! Záložka není definována.. It has been approved by EMA for human use. Because of increasing number of protein or nucleic acid based drugs the need for sophisticated drug delivery systems grows. PLGA nanoparticles (NPs) present exactly such drug delivery system capable of encapsulating large variety of compoundsChyba! Záložka není definována.. Within this study we have researched optimization of separation and purification of drug loaded NPs. They were prepared by nanoprecipitation of PLGAChyba! Záložka není definována.. Separation and purification of NPs was done using multiple cycles of centrifugation. We evaluated purification of particles prepared from five different PLGA polymers. Different centrifugation times were applied to find the most effective way. Water and two types of stabilizers each one in two concentrations have been used as purification...

Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Candidate Mgr. Jana Kubačková Supervisor Assoc. Prof. Jarmila Zbytovská, Mgr., Dr. rer. nat. Co-supervisor PharmDr. Ondřej Holas, PhD. Title of Doctoral Thesis Preparation of pharmaceutical formulations based on polymeric and lipid carriers Nanomedicine allows application of nanoscaled drug delivery carriers to achieve a therapy that can be tailored in terms of e.g. controlled release, site-specific delivery and protection of an active substance. From multiple nanoplatforms available for drug delivery, advantage was taken of biocompatible and biodegradable polymers and lipids to enable targeted intracellular delivery, delivery of a poorly water-soluble drug and delivery of a sensitive macromolecule. In the study with biodegradable polymeric nanomaterial we worked with experimental poly(lactic-co-glycolic acid) (PLGA) polymers. The formulations were optimised for targeting to phagocytic macrophages - of size up to 300 nm and negative surface charge. For this purpose, two linear and one branched PLGA were screened in combination with one of four surfactants in low concentrations (0.1-1%). These PLGA polymers were formulated into nanoparticles and loaded with a hydrophilic fluorescent dye Rhodamine B...

It is fundamental to investigate the biodegradability of chemicals and their potential (eco)toxicological effects under near-environmental conditions in order to identify and thereby avoid potential risks to humans, animals and the environment in the event of their release. Established as a policy object at the European level, the risks, which are posed by anthropogenic pollution, ideally need to be reduced to a minimum, if not eliminated completely, in the near future. To achieve this goal, an assessment of chemicals, based on international consensus, is required, which builds on the results of standardized experiments and is constantly supplemented by computer-based approaches. Establishing structure-property relationships is one way to immediately classify organic trace substances as ‘degradable’, or ‘potentially persistent’, as well as as hormonally ‘active’ or ‘inactive’. The extent to which these relationships are applicable to the substance group of benzophenone-type UV filters was investigated in this work. Some derivatives, which only differ in the type and position of their substituents on the aromatic rings, are suspected of acting as endocrine disruptors. Despite the high probability of them being released into the environment, and the toxicologically relevant properties, there are no mechanistic degradation studies so far that take enough derivatives into consideration to discuss the substitution pattern as a possible influential factor. To close the identified gaps, experiments on primary as well as ultimate degradation were carried out with up to ten different benzophenones, changing various parameters and adapting the experimental setup. Studies on the complete mineralizability, compliant with the standardized OECD Guideline No. 301F, showed that the respective substitution pattern is a decisive factor, while the mere presence of certain functional groups plays a minor role. To yield additional information on the time-dependent formation of primary degradation products, an LC-MS/MS method was developed that served to quantify benzophenones in various environmental matrices during a monitoring campaign, in addition to tracking primary degradation at the laboratory scale. The detection of 4-hydroxybenzophenone, which meets the structural criteria for multi-hormonal effects and was identified as a microbial degradation product of benzophenone, confirmed that the formation of transformation products needs to be given greater consideration in relation to toxicological issues. On this evidence, the structure-dependent endocrine effects of benzophenone-type UV filters, the transformation product 4-hydroxybenzophenone, and three other degradation products were determined using recombinant yeast-based reporter gene assays. Hydroxyl groups are the prevalent substituents of benzophenone-type UV filters, and the ruling structural elements, which influence microbial biodegradation and endocrine activity. Their investigation revealed a new fundamental but unexpected relationship: Primary degradation can slow down further degradation through the incorporation of hydroxyl groups. This simultaneously increases the risk of a formation of estrogen-active transformation products. This aspect underlines the need to include the occurrence of transformation products, especially under realistic conditions, in the overall risk assessment of chemicals. In this context, the application of quantitative structure-activity relationships (QSAR) plays a crucial role and, the suitability thereof was verified in this work – focusing on benzophenones. The empirically proven relationship between substitution pattern and degradability helps to improve the reliability of QSAR models for benzophenones as well as for structurally similar compounds, and forms the basis for further studies of this specific relationship at the enzymatic level.:DECLARATION OF CONFORMITY DECLARATION OF INDEPENDENT WORK PREFACE ACKNOWLEDGMENT KURZFASSUNG ABSTRACT LIST OF ABBREVIATIONS AND ACRONYMS 1 CONTEXTUAL FRAMEWORK AND OBJECTIVES 2 STATE OF KNOWLEDGE ABOUT THE BIODEGRADATION OF BENZOPHENONES 2.1 INTRODUCTION 2.2 ENTRY PATHS INTO THE ENVIRONMENT AND HAZARDOUS EFFECTS 2.2.1 Environmental occurrence and possible routes of discharge 2.2.2 (Eco)toxicity and endocrine disrupting properties 2.3 BIODEGRADATION 2.3.1 Aerobic biotransformation 2.3.2 Anoxic/anaerobic biotransformation 2.3.3 Transformation mediated through fungi and higher organisms 2.4 PHOTOLYTIC TRANSFORMATION 2.5 CONCLUSIONS 3 TRACE ANALYSIS IN ENVIRONMENTAL SAMPLES AND THE ENDOCRINE EFFECTS 3.1 INTRODUCTION 3.2 MATERIAL AND METHODS 3.2.1 Chemicals and materials 3.2.2 LC-MS/MS method development 3.2.2.1 MS parameters 3.2.2.2 LC parameters 3.2.2.3 Sample preparation 3.2.2.4 Validation 3.2.2.5 Application of the method to environmental monitoring 3.2.3 Biodegradation 3.2.4 Yeast-based reporter gene assays 3.3 RESULTS AND DISCUSSION 3.3.1 LC-MS/MS method development 3.3.1.1 Sample preparation 3.3.1.2 Validation 3.3.1.3 Application of the method for environmental samples 3.3.2 Biodegradation 3.3.3 Endocrine activity 3.3.3.1 Estrogenic and antiestrogenic activities 3.3.3.2 Estrogenic activity during biotransformation 3.3.3.3 Androgenic and antiandrogenic activities 3.4 CONCLUSION 4 PRIMARY AND ULTIMATE DEGRADATION 4.1 INTRODUCTION 4.2 MATERIAL AND METHODS 4.2.1 Chemicals and materials 4.2.2 Primary degradation 4.2.2.1 Abiotic river water 4.2.2.2 Biotic river water 4.2.2.3 Suboxic river water 4.2.2.4 River water amended with mineral solution 4.2.3 Ready biodegradability 4.2.4 Column experiments 4.2.5 Docking studies 4.2.6 LC-MS/MS Analysis 4.3 RESULTS AND DISCUSSION 4.3.1 Primary degradation 4.3.1.1 Abiotic river water 4.3.1.2 Biotic river water 4.3.1.3 Suboxic river water 4.3.1.4 River water amended with mineral solution 4.3.2 Ready biodegradability 4.3.3 Column experiments 4.3.3.1 Breakthrough curves and pretests 4.3.3.2 Removal tests 4.3.4 Structure-biodegradability relationships 4.4 CONCLUSIONS 5 SYNTHESIS 5.1 SUMMARIZING DISCUSSION 5.2 COMPARISON TO IN SILICO RESULTS 5.2.1 Biodegradability 5.2.2 Estrogenicity 5.3 CONCLUSION 6 APPENDIX 6.1 APPENDIX A 6.2 APPENDIX B 6.3 APPENDIX C 6.4 APPENDIX D 7 REFERENCES

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Magnesium composites have the potential to be used within the medical setting as a material, particularly for bone implants. Their potential comes from their possession of biodegradability characteristics and material properties that resemble the cortical bone. The biodegradability of the magnesium biomaterials can reduce the need for a second surgery to remove implants when a level of bone regeneration is reached to be self-sufficient, therefore removing the dependency on the implant. However, magnesium in its naturally occurring state demonstrates high corrosivity and degradation when simulated in a biological context. We investigate a magnesium composite (magnesium-bioglass) by testing biodegradation and mechanical properties, evaluating the differences in properties when compared to the mechanical properties of pure magnesium, and analyzing scanning electron microscopy results applied to samples immersed in a solution to simulate the in vivo setting. Through the various modes of fabrication of the magnesium composites, increased bioactivity can be measured. The results support the potential of using the bioactive magnesium-bioglass composites for orthopedic implants.

<p dir="ltr">The first part of this work proposes a solution for the challenge discussed section 1.2.1 by designing and validating a radiative cooling paint that is durable when attached to a substrate, and biodegradable when dispersed into the environment. Said paint also features high solar spectrum reflectivity and high sky window (8-13 microns) emissivity which enables it to achieve sub-ambient surface temperature throughout the day, even under direct sunlight. Full-biodegradation is observed in lab-based biodegradability testing using a comparison test between a biodegradable sample and a non-biodegradable sample. </p><p dir="ltr">The second part of this work demonstrates an innovative dual-layer design featuring a thin layer of leuco dye based thermochromic paint applied on top of a thick layer of BaSO4-based ultra-white daytime radiative cooling paint. This design utilizes thermochromism, a temperature-activated reversible chemical reaction that drastically changes the absorptivity of the affected media. In this work, the leuco dye-based thermochromic top layer effectively works as an autonomous thermal switch that, when temperatures are high and cooling is required, it switches to a "colorless state," enabling the radiative cooling basecoat to reflect incoming sunlight and emit radiatively, effectively cooling the surface. Conversely, when temperatures are low and heating is needed, the thermochromic top layer activates and transforms into an absorbing surface. This activation blocks the reflective and emitting bottom layer from radiatively cooling the surface, and instead absorbs incoming radiation to heats up the surface.</p>

Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: World crude oil demand and production is set to increase in the long term and is projected to increase from 82 barrels per day in 2007 to an estimated 104 million barrels per day in 2030 according to the International Energy Agency. The environmental challenges posed by the current and projected increased future fuel use, with specific reference to air, aquatic and terrestrial impact, are driving producers and legislators to change fuel specifications and consequently fuel properties to be less harmful to the environment. Traditionally transportation fuels are produced through crude oil refining but in South Africa more than one third of the liquid fuels are produced synthetically through catalytic conversion of gassified coal via the Fischer-Tropsch process by Sasol. Diesel from syncrude is referred to as synthetic diesel and the refiner must blend various hydrocarbon streams, effectively tailoring the diesel to its final composition. Biodiesel from renewable sources like vegetable oils is considered environmentally more acceptable than petrodiesel because of its high biodegradability in the environment, lower sulphur and aromatic hydrocarbon content as well as lowered particulate content in the exhaust emissions. The present research was aimed at evaluating whether the composition of diesels derived from different feed stocks, that included coal, natural gas, crude oil and soybean oil, would influence its biodegradability and ecotoxicity. Acute aquatic tests that included freshwater fish, crustaceans, algae and marine bacteria were used to determine the acute toxicity of diesels. In addition, quantitative structure activity relationship models were used to estimate the biodegradation and ecotoxicity properties of the diesels in an attempt to develop a cost effective tool to determine those properties. The results indicated that the 2-D GC technique quantitatively and qualitatively identified the hydrocarbon constituents in the diesels. The relevance of using the 2-D GC technique was in identifying and quantifying the hydrocarbon breakdown products and being used in a mass balance to confirm the potential biological breakdown processes of the materials used in the present study. The differences in theoretical oxygen demand (ThOD) of the different experimental diesel blends using various blending materials and biodiesel, emphasised and confirmed the importance of calculating the ThOD for the respective blending materials when measuring the biodegradation rates. Furthermore, the biodegradation hierarchy of Pitter and Chudoba (1990) in order of decreasing biodegradability: alkanes > branched alkanes > cyclo-alkanes > aromatic hydrocarbons, could be expanded to include FAME: FAME > alkanes > branched alkanes > cyclo-alkanes > aromatic hydrocarbons. The biochemical pathways identified for the biodegradation of all the diesels was enzyme-enhanced β-oxidation. The present research also indicated that biodiesel addition to crude-derived diesels to increase the density to within the current required specifications for diesels cannot be a reality in SA because of the underdeveloped biodiesel industry. To increase the density by using biodiesel to within the specification for GTL diesel, more than 27% biodiesel would be required, which is currently is not achievable from an economic perspective as well as governmental national strategy perspective. The addition of biodiesel as lubricity enhancer seems more plausible, because less than 5% would be required for petrodiesels. The results on the ecotoxicity of the diesels and diesel blends demonstrated a general lack of acute toxic effect, especially for the fish and crustaceans used during the present study. Although algal and bacterial tests showed an effect at most of the WAF loading rates, none were high enough to enable the calculation of a median effect loading rate (EL50). QSAR‟s, like EPI Suite, together with prediction models, like the Fisk Ecotoxicity Estimation Model, can be used to screen for ecotoxicity and biodegradability of hydrocarbons found in Petrodiesels. It was less applicable for the prediction of biodiesel constituents. The use of different cut-off values for the constituents of biodiesel could be developed in future research. The use of this combination enabled the present research into the potential toxicity of hydrocarbon mixtures to be conducted, especially since tests on individual constituents are impractical. QSAR‟s may provide a relatively cost-effective way to screen for potential environmental acceptability of such mixtures. The contributors to the toxicity of mixtures of hydrocarbons found in diesels were evaluated and it appears that paraffins contribute more to the overall toxicity than previously thought and aromatics less. By putting well-defined policies and incentives in place, a robust biodiesel industry could be created that will enable SA to contribute to the mitigation of the threat of climate change, to become less dependent on foreign oil and to develop rural agriculture. The key to energy security is not one solution to South Africa‟s energy needs, but a multifaceted approach to the complex subject of sustainable energy security. The end of the hydrocarbon era of energy is not in sight, at least for the near future, but soon even hydrocarbon energy in the form of coal and crude oil will have to be re-evaluated as SA‟s major energy resource for economic and energy security. In SA the potential of developing natural gas resources through fracking, nuclear, solar, wind, biological and even wastes to energy processes as well as better energy efficiency, in a balanced and diverse energy portfolio, could pave the way toward energy security in the long run. / AFRIKAANSE OPSOMMING: Ru-olie aanvraag en produksie wêreldwyd is besig om toe te neem en die Internasionale Energie Agentskap projekteer dat wêreld ru-olie verbruik sal toeneem van 82 vate per dag in 2007 tot „n beraamde 104 vate per dag in 2030. Die omgewings uitdagings wat huidige en toekomstige toename in brandstof verbruik, spesifiek die impak op lug gehalte, water- en grond, mag hê, is dryfvere vir produseerders en reguleerders om brandstof spesifikasies te verander om minder omgewings impak te veroorsaak. Brandstof vir vervoer doeleindes word oor die algemeen van ru-olie gemaak, maar in Suid Afrika word ongeveer „n derde van die vloeibare brandtof gemaak deur middel van gekatiliseerde omskakeling van vergasde steenkool via die Fischer-Tropsch proses by Sasol. Diesel wat uit sintetiese ru-olie gemaak is, is sinteties en die raffineerder moet verskillende koolwaterstof strome meng om „n finale produk te lewer. Biodiesel wat uit hernubare hulpbronne soos plant-olies en diervet gemaak word, kan oorweeg word vir die vervaardiging van meer omgewings aanvaarbare brandstof met laer swael en aromatiese koolwaterstof inhoud en ook minder partikel inhoud in die uitlaatgas. Die huidige navorsing het beoog om te evalueer of die samestelling van diesels wat vervaardig is uit verskillende hulpbronne, wat steenkool, aardgas, ru-olie en sojaboon olie ingesluit het, die biodegradeerbaarheid en ekotoksisiteit kan beïnvloed. Akute akwatiese toetse wat varswater vis, krustaseë, alge en marine bakterieë ingesluit het, was aangewend om die akute toksisiteit van die diesels te bepaal. Kwantitatiewe struktuur aktiwiteit verwantskaps modelle is ook gebruik om die biodegradeerbaarheid en ekotoksisiteits eienskappe van die diesels te beraam om vas te stel of 'n bekostigbare alternatief beskikbaar is om daardie eienskappe te bepaal. Die resultate het aangedui dat die 2D GC tegniek kwantitatief en kwalitatief gebruik kan word om die koolwaterstowwe in die diesels te identifiseer. Die benutting van die 2D GC tegnieke is egter om die koolwaterstof afbraak produkte te identifiseer en ook om die massa balans gedurende die biodegradering te bevestig. Die verskil in teoretiese suurstof aanvraag van die verskillende diesels het die belangrikheid daarvan blemtoon en bevestig om die teoretiese suurstof aanvraag korrek te bereken en sodoende die biodegradasie korrek te bepaal. Verder kan die biodegradasie hierargie van Pitter en Chudoba (1990) volgens afnemende biodegradasie: alkane > vertakte alkane > siklo-alkane > aromatiese koolwaterstowwe, uitgebrei word om vetsuur-metielesters in te sluit: vetsuur-metielesters > alkane > vertakte alkane > siklo-alkane > aromatiese koolwaterstowwe. Die biochemiese roetes wat geïdentifiseer is vir die biodegradasie van die diesels, was ensiem-verbeterde β-oksidasie. Die huidige navorsing het ook aangedui dat biodiesel toevoeging tot ru-olie vervaardigde diesel om die digtheid te verhoog to binne huidige spesifikasies is nog nie lewensvatbaar in Suid Afrika nie as gevolg van die onderontwikkelde biodiesel industrie. Om die digtheid te verhoog met biodiesel tot binne spesifikasie verg meer as 27% biodiesel en is huidiglik nie haalbaar vanuit 'n ekonomiese persketief en ook nie vanuit 'n regerings nasionale strategie perspektief nie. Die toevoeging van biodiesel as lubrisiteits vervetering blyk meer van toepassing te wees aangesien minder as 5% biodiesel toevoeging benodig sou wees. Die resultate van die ekotoksisiteits toetse het 'n algemene gebrek aan akute toksisiteits effek aangedui, veral vir vis en skaaldiere wat in die huidige studie gebruik is. Howel alge en bakteriële toetse daarop gedui het dat 'n toksiese effek wel aanwesig was, was dit gering en kon die median effektiewe ladings koers (EL50) nie bepaal word nie. QSARs, soos Epi Suite, tesame met voospellings modelle, soos die Fisk Ecotoxicity Estimation Model, kan gebruik word om ekotoksisiteit en biodegradeerbaarheid van koolwaterstowwe in petrodiesels te beraam, alhoewel dit minder van toepassing was op biodiesel. Die gebruik van ander afsny waardes spesifiek vir biodiesel kan oorweeg word in toekomstige navorsing. Die molecules wat bygedra het tot die toksisiteit van die koolwaterstof mengsels was geëvalueeren daar is gevind dat die paraffiniese molekules meer begedra het tot die totale toksisiteit en die aromate minder. Deur goed gedefinieerde beleid en aansporings meganismes inplek te sit, kan 'n biodiesel industrie in SA geskep word wat SA sal help om by te dra tot die bekamping van klimaats vendering en sodoende minder afhanklik te wees van buitelandse olie en ook landbou in SA te bevorder. Die sluetel tot energie sekuriteit is nie een oplossing vir SA se energie aanvraag nie, maar eerder 'n veelsydige benadering tot die komplekse onderwerp van volhoubare energie sekuriteit. Die einde van koolwaterstof energie is nog nie in sig nie, ten miste nie in die nabye toekoms nie, maar binnekort sal selfs koolwaterstof energie in die vorm van steenkool en ru-olie heroorweeg moet word as SA se hoof energie hulpbronne vir ekonomiese en energie sekuriteit. In SA moet die potensiaal van natuurlike gas ontginning deur middel van hidrauliese breking, kernkrag, wind energie, biologiese energie en selfs afval tot energie prosesse bestudeer word, so-ook beter energie doeltreffendheid om sodoende 'n gebalansweerde energie portefuelje te skep wat die weg sal baan na energie sekuriteit op die lang termyn.

<p>During pulp and papermaking process a huge amount of water is used. The wastewater contains a large amount of pollutants and has to be treated before it reaches the recipient. In March 2004 a new bleaching plant was started up at SCA Graphic Sundsvall AB, Ortviken’s paper mill using peroxide. The production of bleached thermo mechanical pulp and thus the load to the wastewater plant increased. During bleaching substances dissolve from the pulp and the amount of COD in the wastewater increase. To keep the efficiency of chemical and biological oxygen demand (COD, BOD) removal, the aerated lagoon is supplied by liquid oxygen. In November the same year a new pre-step including a pre-aeration, carrier and selector step was added to the existing wastewater plant. The COD-loading to the lagoon decreased and the supply of liquid oxygen was reduced.</p><p>This master thesis has been carried out at SCA Graphic Research AB, Sundsvall. The aim was to chemically characterize the wastewater with focus on the composition of carbohydrates, lignin and extractives and its influence on the biodegradability. Measurements have been carried out on total samples, suspended solids, colloidal and dissolved substances using GF/A and ultra filtration. Measurements were performed on process water from the bleaching plant and on water during the wastewater treatment process. The results show that the chemical composition of dissolved substances has a larger impact on the biodegradability than the total amount of COD. A large amount of lignin will make the wastewater harder to degrade. Suspended solids have lower biodegradability compared to the dissolved fraction. Analyzes of suspended material from the bleaching plant show a relative composition of around 41 % lignin. Analyzes done before on the dissolved fraction show a composition of 29 %. It seems that a larger amount of lignin is represented in suspended solids compared to the dissolved fraction. This can explain the low biodegradability, combined with the theory that the suspended solids are less accessible for the microorganisms. To reduce the outgoing COD the incoming flow of dissolved lignin and suspended solids to the active sludge plant has to decrease. COD in the outgoing wastewater to the recipient consists of around 90 % lignin. Extractives as saturated fatty acids, palmitic and stearic acid plus lignans (which is interpreted as a byproduct from lignin degradation) do not degrade remarkable during wastewater treatment. Flocculation of COD is one way to reduce the discharge to the recipient. Addition of 2,6 g/l PAX-18 (a high charged aluminum complex) to the wastewater from the bleaching plant gives a reduction of 40 % COD and 50 % lignin in laboratory scale and it is recommended to study further. Time related studies of BOD show that the microorganisms need five days to degrade organic material and the hydraulic retention time in the aerated lagoon has to be guaranteed.</p> / <p>Vid massa- och pappersframställning åtgår stora mängder vatten. Det processberörda avloppsvattnet innehåller mycket föroreningar varför det måste renas innan det släpps ut till recipienten. I mars 2004 startades ett nytt väteperoxidblekeri vid SCA Graphic Sundsvall AB, Ortvikens pappersbruk varvid produktionen av blekt termomekanisk massa ökade och den biologiska reningen belastades hårdare. Blekning löser ut vedämnen från massan och bidrar således till ökad mängd syreförbrukande ämnen i avloppet. För att upprätthålla reduktionen av syreförbrukande ämnen (COD, BOD) tillförs ren syrgas till den luftade dammen. I november samma år utökades den externa reningsanläggningen med ett biologiskt försteg, en s.k. multibioanläggning bestående av ett frisimmarsteg, ett bärarsteg samt ett selektorsteg. COD-belastningen in till den luftade dammen minskade och tillförseln av ren syrgas kunde reduceras.</p><p>Examensarbetet har utförts vid SCA Graphic Research AB, Sundsvall med syftet att kemiskt karaktärisera avloppsvattnets sammansättning av kolhydrater, lignin och extraktivämnen och dess inverkan på vattnets grad av biologisk nedbrytbarhet. Analyser har gjorts på totalprov, suspenderande ämnen samt kolloidalt och löst material via fraktionering med hjälp av GF/A- och ultrafiltrering. Analyser gjordes dels på processvatten från blekerierna och dels på avloppsvatten under reningsprocessen. Resultaten visar att den kemiska sammansättningen hos löst material har större inverkan på avloppsvattnets grad av nedbrytbarhet än den absoluta halten av syreförbrukande ämnen. En hög andel lignin ger ett mer svårnedbrytbart vatten. Suspenderat material är vidare mer svårnedbrytbart än de lösta fraktionerna. Analys av suspenderande substans hos blekpressat visar att andelen lignin är omkring 41 % medan arkiverade analysresultat på den lösta fasen visar ett innehåll på omkring 29 %. Det tyder alltså på en betydligt högre andel lignin i den partikulära fasen jämfört med den lösta, vilket i kombination med att materialet inte är lika lättillgängligt för mikroorganismerna kan förklara den låga bionedbrytbarheten. Om COD-utsläppet ska minskas bör inkommande flöde av löst lignin och suspenderande substans till den biologiska reningen reduceras. COD-halten i utgående avloppsvatten till recipienten utgörs av omkring 90 % lignin. De extraktivämnen som inte bryts ned är mättade fettsyror, exempelvis palmitin- och stearinsyra samt lignan, vilket antas bildas som restprodukt vid degradering av lignin. Flockning av syreförbrukande ämnen är ett sätt att gå till väga för att minska utsläppet av dessa till recipienten. Genom tillsats av 2,6 g/l PAX-18 (ett högladdat aluminiumkomplex) till blekeriavloppet kunde 40 % COD och 50 % lignin reduceras. Flockningsförsöket är gjort i laboratorieskala vid rumstemperatur och ytterligare utvärdering rekommenderas. Tidsstudier av BOD visar att mikroorganismerna behöver fem dagars uppehållstid för att hinna bryta ned organiskt material i avloppsvattnet, varför omloppstiden i den luftade lagunen inte bör understiga denna tidsrymd.</p>

O presente trabalho teve como principal objetivo avaliar o desempenho de um reator anaeróbio híbrido (RAnH) em escala piloto no tratamento da fração líquida de estrume bovino, visando à remoção de matéria orgânica e à produção de biogás. O RAnH estudado apresentava volume total 6,2 m3 e foi composto por manta de lodo, na qual a biomassa encontrava-se suspensa, e leito fixo, no qual utilizou-se Biobob&#174; como material suporte para imobilização da biomassa. Para dar suporte a partida do RAnH, a água residuária em estudo foi submetida a teste de biodegradabilidade visando avaliar a influencia da inoculação do reator no potencial de biodegradabilidade e de produção de metano. No teste, a inoculação mostrou-se adequada, apresentando biodegradabilidade de 57 &#177; 4% e produção de metano de 344 &#177; 26 mL CH4. g SV-1. A operação do RAnH foi realizada por 260 dias e foi dividida em duas etapas: etapa inicial, na qual se procedeu a adequação da operação do reator, e etapa experimental, na qual se avaliou o desempenho do reator perante o aumento progressivo da carga orgânica aplicada. Durante a operação do reator foi alcançada a aplicação de COV bruta total de 25,50 &#177; 2,53 kg DQO.m-3.d-1 e a COV solúvel total de 7,69 &#177; 0,02 kg DQO.m-3.d-1, sendo atingido o TDH de 1,27 &#177; 0,004 d. O RAnH apresentou eficiência de remoção média de 65 &#177; 4 % durante a etapa experimental. A produção média de metano foi de 0,310 &#177; 0,095 m3 CH4. m-3.d-1 e 0,098 &#177; 0,018 m3 CH4. kg SVad, com 89 &#177; 3% de metano na composição do biogás. O potencial de produção de energia elétrica estimada com base no reaproveitamento metano produzido no RAnH foi de 0,89 kWh.m-3. O aproveitamento desta energia em sistema com vazão de 3.500 m3.d-1 geraria energia suficiente para abastecer 615 residências e uma economia mensal de R$ 11.835,09. / The main objective of this work was to evaluate the performance of a pilot-scale anaerobic hybrid reactor (RAnH) in the treatment of the liquid fraction of dairy manure, in order to remove organic matter and produce biogas. The applied RAnH had a total volume of 6.2 m3 and was composed of sludge blanket, in which the biomass was suspended, and fixed bed, in which Biobob&#174; was applied as a support material for biomass immobilization. In order to support RAnH startup, the wastewater under study was submitted to a biodegradability test to evaluate the influence of reactor inoculation on the biodegradability potential and methane production potential. In the test the inoculated condition presented appropriate biodegradability (57 &#177; 4%) and higher methane production potential (344 &#177; 26 mL CH4.gVS-1). The RAnH operation was performed for 260 days and was divided into two stages: initial stage, in which the reactor operation was adjusted, and the experimental stage, in which the reactor performance was evaluated with the progressive increase of the applied organic load. During the reactor operation was reachead total raw VOC application of 25.50 &#177; 2.53 kg COD m-3.d-1 and total soluble VOC of 7.69 &#177; 0.02 kg COD m-3.d-1, with the HRT of 1.27 &#177; 0.004 d. The RAnH presented average removal efficiency of 65 ± 4% during the experimental stage. The average methane production was 0.310 &#177; 0.095 m3 CH4.m-3.d-1 and 0.098 &#177; 0.018 m3 CH4. kg VSad, with 89 &#177; 3% of methane in the biogas composition. The potential of electric energy production estimated based on the reuse of the methane produced in the RAnH was 0,89 kWh.m-3. The use of this energy in a system with a flow of 3,500 m3.d-1 would generate sufficient energy to supply 615 homes and a monthly saving of R$ 11,835.09.