With electricity tariffs in South Africa escalating at a rapid pace the demand for alternative power sources has increased. One of these renewable energy sources includes the use of biogas. Biogas is not only one of the most efficient and effective renewable energy possibilities available but also requires less capital investment as compared to other renewable sources like hydro, solar and wind and are also more economical as it involves less per unit production cost. Biogas plants have been used around the globe for numerous years, but are a relative new technology in South Africa, predominantly in the red meat industry with the use of slaughter waste as a form of biomass. Slaughter waste offers a vital possible source of renewable energy. A variation of factors makes the production of renewable energy from slaughter waste particularly appealing. The continuous rise of energy prices, waste disposal prices, and incentives for renewable energy production have increased the value of outputs from slaughter waste-to-energy systems. The primary objective of the research is assessing the economic viability of biogas plants at abattoirs in South Africa and if such a biogas plant would be beneficial to an abattoir. The research aimed to determine the viability through various capital budgeting techniques and define what the most significant calculated variables are that should be addressed in such an economic viability model. For the purposes of this study a Class A abattoir with a slaughtering capacity of 400 cattle per day was used as a case study. Biogas will be generated through anaerobic digestion and the utilising of the gas for the generation of electricity and heat by means of a CHP generator. The economic viability study contains of a base case scenario and two other possible scenarios and provides recommendations and a concluding report, based on the scenario that is the most viable. The succeeding techniques which were recognised were used to analyse the economic viability of the biogas plant: Payback Period, Discounted payback period, Net present value, profitability index, and internal rate of return. Furthermore a sensitivity analysis was done in the study with a pessimistic and optimistic outcome on key variables. The study establish that in the base case scenario a positive net present value was realised, the internal rate of return was more than the required rate of return and the payback periods was shorter than required. In this study the concept of biogas plants in the red meat industry were researched with the purpose of determining the economic viability of these plants. In determining the viability of the biogas plant the key variables that will impact the viability was also identified and discussed. Based on the data gathered and assumptions that was made it was concluded that a biogas plant will be beneficial to an abattoir and was considered economically viable. / MBA, North-West University, Potchefstroom Campus, 2014

Made available in DSpace on 2014-06-11T19:32:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-31Bitstream added on 2014-06-13T19:22:44Z : No. of bitstreams: 1 maluta_rp_dr_jabo.pdf: 440520 bytes, checksum: 3c6ccf7fa3a09af508156250e6a377c0 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Canadian Bureau For International Education (Cbie) / Os ruminantes são reservatórios de cepas de Escherichia coli envolvidas na etiologia de doenças graves em humanos. Nesse estudo, a freqüência de E. coli Shigatoxigênica (STEC), E. coli enteropatogênica (EPEC) e E. coli enterotoxigênica (ETEC) foi determinada em fezes e carcaças de ovinos em três fazendas e um matadouro-frigorífico localizados no Estado de São Paulo e as cepas encontradas foram caracterizadas. A freqüência de STEC nas três fazendas foi similar, enquanto a freqüência de EPEC foi variável. Não foram encontradas amostras contendo ETEC. As cepas de STEC stx1- stx2+ revelaram-se geneticamente heterogêneos, possuindo freqüentemente as variantes Stx2a ou Stx2dact, as quais são relacionadas à doenças mais severas em humanos e ademais eles foram freqüentemente originados de amostras colhidas do matadouro-frigorífico. Adicionalmente, algumas cepas desse grupo possuíram novas variantes de Stx2 ou o subtipo Stx2e, que é relacionado à doença do edema em suínos. As cepas de STEC stx1+ stx2+ e stx1+ stx2- mostraram-se geneticamente mais homogêneas, a maioria possuindo os genes lpfAO113, iha e ehxA. As cepas de STEC stx1+ stx2- apresentaram comumente o gene relacionado à ExPEC tsh. As estirpes de EPEC foram heterogêneas, muitas possuíram os genes efa1, ehxA, lpfAO113 ou paa, que são associados à diarréia em humanos. As cepas de STEC e EPEC demonstraram-se geneticamente diversas quando analisadas por PFGE. Esses resultados demonstram que cepas de E. coli potencialmente patogênica para humanos estão presentes na microbiota intestinal de ovinos, com potencial de contaminar carcaças em abatedouro e conseqüentemente serem transmitidas por via alimentar / Ruminants are a reservoir of Escherichia coli which may cause severe disease in humans. Pathotypes related to intestinal disease include Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli (EPEC) and enterotoxigenic E. coli (ETEC). In this study, the prevalence of these pathotypes was examined in sheep feces and carcasses on three farms and at an abattoir. The strains were then characterized. The prevalence of STEC on the three farms was similar, whereas that of EPEC varied between farms. No ETEC were detected. STEC stx1- stx2+ strains were genetically heterogeneous, more frequently possessing Stx2 variant Stx2a or Stx2dact related to more severe disease in humans, and often originated from the abattoir rather than the farms. In addition, some strains of this group possessed new Stx2 variants or Stx2e, the subtype related to porcine edema disease. STEC stx1+ stx2+ and stx1+ stx2- strains were genetically more homogeneous, mostly possessed the genes lpfAO113, iha and ehxA. The STEC strains stx1+ stx2- commonly harbored ExPEC-related gene tsh. The EPEC strains were heterogeneous, several possessing efa1, ehxA, lpfAO113 or paa, genes associated with diarrhea in humans. STEC and EPEC strains were genotypically diverse by PFGE. These results demonstrate that E. coli potentially pathogenic for humans are present in the sheep intestinal microflora, particularly at the abattoir, underlining the potential for foodborne transmission

Orientador: Fernando Antônio de Ávila / Banca: Beatriz Ernestina Cabilio Guth / Banca: Ariel Eurides Stella / Banca: Hélio José Montassier / Banca: José Moacir Marin / Resumo: Os ruminantes são reservatórios de cepas de Escherichia coli envolvidas na etiologia de doenças graves em humanos. Nesse estudo, a freqüência de E. coli Shigatoxigênica (STEC), E. coli enteropatogênica (EPEC) e E. coli enterotoxigênica (ETEC) foi determinada em fezes e carcaças de ovinos em três fazendas e um matadouro-frigorífico localizados no Estado de São Paulo e as cepas encontradas foram caracterizadas. A freqüência de STEC nas três fazendas foi similar, enquanto a freqüência de EPEC foi variável. Não foram encontradas amostras contendo ETEC. As cepas de STEC stx1- stx2+ revelaram-se geneticamente heterogêneos, possuindo freqüentemente as variantes Stx2a ou Stx2dact, as quais são relacionadas à doenças mais severas em humanos e ademais eles foram freqüentemente originados de amostras colhidas do matadouro-frigorífico. Adicionalmente, algumas cepas desse grupo possuíram novas variantes de Stx2 ou o subtipo Stx2e, que é relacionado à doença do edema em suínos. As cepas de STEC stx1+ stx2+ e stx1+ stx2- mostraram-se geneticamente mais homogêneas, a maioria possuindo os genes lpfAO113, iha e ehxA. As cepas de STEC stx1+ stx2- apresentaram comumente o gene relacionado à ExPEC tsh. As estirpes de EPEC foram heterogêneas, muitas possuíram os genes efa1, ehxA, lpfAO113 ou paa, que são associados à diarréia em humanos. As cepas de STEC e EPEC demonstraram-se geneticamente diversas quando analisadas por PFGE. Esses resultados demonstram que cepas de E. coli potencialmente patogênica para humanos estão presentes na microbiota intestinal de ovinos, com potencial de contaminar carcaças em abatedouro e conseqüentemente serem transmitidas por via alimentar / Abstract: Ruminants are a reservoir of Escherichia coli which may cause severe disease in humans. Pathotypes related to intestinal disease include Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli (EPEC) and enterotoxigenic E. coli (ETEC). In this study, the prevalence of these pathotypes was examined in sheep feces and carcasses on three farms and at an abattoir. The strains were then characterized. The prevalence of STEC on the three farms was similar, whereas that of EPEC varied between farms. No ETEC were detected. STEC stx1- stx2+ strains were genetically heterogeneous, more frequently possessing Stx2 variant Stx2a or Stx2dact related to more severe disease in humans, and often originated from the abattoir rather than the farms. In addition, some strains of this group possessed new Stx2 variants or Stx2e, the subtype related to porcine edema disease. STEC stx1+ stx2+ and stx1+ stx2- strains were genetically more homogeneous, mostly possessed the genes lpfAO113, iha and ehxA. The STEC strains stx1+ stx2- commonly harbored ExPEC-related gene tsh. The EPEC strains were heterogeneous, several possessing efa1, ehxA, lpfAO113 or paa, genes associated with diarrhea in humans. STEC and EPEC strains were genotypically diverse by PFGE. These results demonstrate that E. coli potentially pathogenic for humans are present in the sheep intestinal microflora, particularly at the abattoir, underlining the potential for foodborne transmission / Doutor

The usage of antimicrobials either as performance enhancers or for prophylactic and therapeutic purposes in food animals, such as chickens, increases the prevalence of antimicrobial drug resistance among enteric bacteria of these animals. This may be transferred to people working with such animals, e.g. abattoir workers, or the products arising from these animals. In this study antimicrobial drug resistance was investigated for selected enteric bacteria from broilers raised on feed supplemented with antimicrobial growth enhancers, and the people who carry out evisceration, washing and packing of intestines in a high throughput poultry abattoir in Gauteng, South Africa. Poultry farms (n=6) were purposively selected on the basis of allowing for sampling of farms from more than one grow out cycle. Broiler carcases (n=100) were randomly selected per farm five minutes after slaughter and sampled by incising caecae from the rest of the gastro-intestinal tract (GIT). The ends of each caecae were tied off to prevent contamination and to enhance the culturing of anaerobic bacteria. In the laboratory, caecal contents were selectively cultured for Clostridium perfringens, Escherichia coli, Enterococcus faecium, E. faecalis, and vancomycin-resistant enterococci (VRE). Salmonella enterica was isolated using pre-enrichment followed by selective culture. The minimum inhibitory concentration (MIC) micro broth dilution test as prescribed by the Clinical and Laboratory Standards Institute USA (CLSI), previously known as National Committee of Clinical Laboratories (NCCL), was used to determine the susceptibility of the isolates to the following antimicrobials: vancomycin, virginiamycin, doxycycline, trimethoprim, sulphamethoxazole, ampicillin, bacitracin, enrofloxacin, erythromycin, fosfomycin, ceftriaxone and nalidixic acid. The same was done on the faeces of 29 abattoir workers exposed to potentially resistant micro-organisms from broilers and 28 persons used as controls, who had not been equally exposed to potentially resistant micro-organisms from broilers. Both of the human populations had not been treated with antimicrobials within three months prior to sampling. Statistical analysis was done by Fisher’s exact test. No salmonellae and VRE on VRE selective agar (Oxoid UK) were cultured. Two Clostridium perfringens, 168 E. coli, 20 E. faecalis and 96 E. faecium isolates from the broiler caecae were cultured. Fifty four (28 and 26) E. coli, 24 (21 and 3) E. faecalis and 12 (2 and 10) E. faeciumfrom humans were cultured. The figures in brackets represent the abattoir workers and human controls respectively. The majority of E. coli isolates from broilers had MIC’s above the cut off point for the antimicrobials tested. Low resistance was observed among broiler enterococci isolates to vancomycin, virginiamycin, trimethoprim and ampicillin. A comparison of the median MIC’s of isolates from abattoir workers (packers) and the control group revealed significant differences in the median MIC’s for the following antimicrobials; E. faecalis: enrofloxacin (p=0.019). E. faecium, trimethoprim (p=0.01), enrofloxacin (p=0.029) and erythromycin (p=0.03). E. coli: trimethoprim (p=0.012) and ampicillin (p=0.036). Use of antimicrobials as feed additives causes resistance among enteric bacteria from broilers. Significant differences between median MIC’s of abattoir workers (packers) and the control group were observed for therapeutics and not growth enhancers. There was a tendency for isolates from abattoir workers to have a higher median MIC and a higher number of resistant isolates as compared to the control group. In spite of the fact that there was a high level of resistance in the enteric commensal bacteria of broiler caecae, an association could not be shown with that of the human enteric bacteria. It could not be concluded that a significant AMR transfer to poultry abattoir workers existed. This notwithstanding, both the control and experimental group, carried levels of resistance among their enteric bacteria that could be described as being high. / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2007. / Paraclinical Sciences / unrestricted

Published Article / The Meat Safety Act, Act 40 of 2000 compels all registered abattoirs in South Africa to implement and maintain a Hygiene Management System (HMS) to ensure the safe processing of meat. The HMS is a basic food safety system that focuses on process standards that are designed to reduce the risk of contamination of meat and meat products during processing. Part of the Poultry regulations provide the requirements of HMS and were published by government on the 24th of February 2006. However, no guidelines were published or made available to poultry abattoir operators on how to interpret and implement the requirements of the HMS. The aim of this research was to determine the extent of HMS implementation at poultry abattoirs in Gauteng. The intention was to identify short comings, if any, within implemented HMSs with the intention of promoting compliance. This was achieved by developing common themes from research audit findings. These themes were then used to suggest critical areas that should be addressed during the development of an HMS implementation guideline document.

<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>

This dissertation is a contribution to the ethnography of contemporary indigenous reindeer pastoralism in Norway: specifically, to the study of the neglected fields of reindeer killing and slaughtering practice. Its central contention is that in recent decades, the proliferation of human powers vested in the conduct of reindeer slaughter has created new conditions for practice, placing the identities of reindeer and herders at stake in new and still only dimly conceptualized ways. By exploring these, the dissertation aims to broaden existing debates concerning the so-called modernization of pastoral practice in Norway, drawing attention to some of its neglected aspects and inscribing them in a new register. Two principal strands inform the theoretical framework: one, approaches to the social study of knowledge that emphasise its practical, non-verbal and material aspects; and two, Foucauldian concepts of biopower as these may or may not be applicable to the human management of animal life. Individual chapters examine, in turn: the local politics of space on the Varanger peninsula, focusing particularly on links between the spatial management and the killing of reindeer; the practices and social relations of slaughter as it is conducted at the round-up corral; the social effects of the introduction of slaughterhouses, and of the regime of which they form a part; controversies surrounding specific slaughtering techniques and instruments, particularly the curved knife; and the politics of animal welfare discourse and practices in their application to reindeer herding. Finally, using the figure of animal sacrifice as a guiding trope, the concluding chapter attempts to situate some key aspects of the modernization of reindeer slaughter in relation to the operation of broader sacrificial economies that regulate the destruction of life at aggregate or populational levels.

L'abattoir est un observatoire privilégié de la santé des bovins, permettant d'envisager une surveillance de la population bovine à partir des données d'inspection sanitaire qui y sont collectées. Mais la valorisation épidémiologique de ces données fait face à des difficultés (complexité des données, nombreux mouvements des bovins de leur naissance à l'abattoir). Afin de gérer cette complexité, une approche statistique (analyse multifactorielle et classification mixte) associée à des avis d'experts ont permis d'établir une typologie des lésions observées à l'abattoir. Une dizaine de groupes lésionnels ont été identifiés qui relèvent de divers domaines tels que la santé animale, la protection animale ou la santé publique. Les données d'abattoir peuvent être utilisées pour la surveillance de maladies ciblées telles que la cysticercose bovine. Des indicateurs de surveillance robustes ont été élaborés pour permettre la comparaison des prévalences de cette zoonose dans le temps et l'espace. Une méthode innovante de prise en compte de l'incertitude liée au lieu d'infestation des animaux a été mise en oeuvre pour identifier les zones à risque plus élevé d'infestation. Un tel outil sera mobilisable pour la mise en oeuvre ultérieure d'une inspection basée sur le risque visant à améliorer l'efficience de l'inspection en abattoir. L'utilisation des données d'abattoir pour la mise en place d'un dispositif de surveillance syndromique a par ailleurs été investiguée par modélisation de la proportion hebdomadaire de bovins ayant fait l'objet d'une saisie totale. Une évaluation des performances de plusieurs algorithmes de détection d'anomalies temporelles a été menée sur données simulées / The slaughterhouse is a unique dedicated vantage point from which to observe bovine health, making it possible to consider implementation of bovine surveillance based on meat inspection data. But the exploitation of these data for epidemiological purposes is not without difficulties (data complexity, large number of cattle movements from birth to slaughter). In order to deal with the data complexity issue, a statistical approach (multiple factor analysis in combination with clustering methods), in addition to the gathering of expert opinions, enables us to create a typology of the lesions detected at the slaughterhouse. Approximately ten lesion groups were identified which cover various areas including animal heath, animal welfare and public health. Meat inspection data can be used for the surveillance of targeted diseases such as bovine cysticercosis. Robust surveillance indicators have been created to enable prevalence comparisons of this zoonosis over time and space. An innovative approach that takes into account uncertainty regarding the location where the animal became infected was implemented to identify areas of higher risk of infection. A similar method could be used for the implementation of a future risk-based meat inspection initiative so as to improve meat inspection efficiency. The use of meat inspection data for the implementation of a syndromic surveillance system was investigated using a temporal analysis of the weekly proportion of whole carcass condemnations, and assessment of the performance of several algorithms for temporal aberration detection was conducted on simulated data

Cette thèse examine la question de la santé au travail des agents publics en abattoir dans sa multi-dimensionnalité. Elle livre une analyse du travail dans le secteur public non seulement à partir de son cadre institutionnel, mais aussi des multiples interactions, souvent interdépendantes, entre l’activité, les organisations et la trajectoire de la politique du contrôle en abattoir. Elle bat en brèche à la fois la présomption de qualité au travail dans le secteur public et la forte étanchéité de ce secteur. Elle montre comment les douleurs sont négociées, entre activité quotidienne et dispositifs de déclaration en maladie professionnelle et de reclassement. A partir des années 2000, une part croissante des agents de l’Etat en abattoir souffrent de troubles musculo-squelettiques. Les TMS sont l’occasion pour l’encadrement intermédiaire de négocier avec les abattoirs mais aussi d’énoncer le « vrai travail » des agents en abattoir. La mise sur l'agenda de la santé au travail des agents affectés dans les abattoirs surgit dans le contexte de redéfinition des missions de l'Etat et les évolutions de la politique du contrôle en abattoir contribuent tantôt à faire émerger la santé au travail, tantôt à l’occulter en laissant de côté la question du devenir des agents dont les missions évoluent et dont le métier est susceptible de disparaître. Au croisement de la sociologie des groupes professionnels, de la santé au travail et de la sociologie de l’action publique, le cadre d’analyse propose d’articuler les régulations liées à la santé et aux conditions de travail à celles de l’activité et du métier d’inspecteur lui-même. / This thesis considers the occupational health of public officials in slaughterhouses in its multi-dimensionality. It provides an analysis of work in the public sector, not only from its institutional framework, but also from the many interactions, often interdependent, between the activity, the organizations and the trajectory of food safety policy. It undermines both the presumption of quality at work in the public sector and the strong tightness of this sector. It shows how pain is negotiated, between daily activity and occupational disease reporting and reclassification schemes. From the 2000s, a growing proportion of officials in slaughterhouses suffered from musculoskeletal disorders. MSDs are an opportunity for middle management to negotiate with slaughterhouses, but also to state the "real work" of slaughterhouse agents. The agenda setting of the occupational health of the agents affected in the slaughterhouses arises in the context of redefining the missions of the State and the evolutions of the food safety policy contribute sometimes to make emerge health at work, to overshadow it by leaving aside the question of the future of those officials whose missions evolve and whose profession is liable to disappear. At the crossroads between the sociology of professions, occupational health and the sociology of public action, the analysis framework proposes to articulate the regulations related to health and working conditions to those of the activity and the profession of inspector himself.

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.