Bioreduction has been proposed as an on-farm storage facility for fallen stock prior to final disposal in accordance with the Animal By-Products Regulations, ABPR (EC 1069/2009). In order for bioreduction to be approved under the legislation it must be shown to be biosecure. Therefore, the main aim of this thesis was to assess the risk of pathogen proliferation in the liquor and bioaerosols generated under operational and simulated breakdown scenarios. Secondary objectives consisted of improving the technology and included: determining the efficacy of commercial accelerants in catalysing the bioreduction process; the use of the carbon footprint to identify potential environmental improvements in future vessel designs; and identifying the main physicochemical parameters and enzyme activity associated with bioreduction, in order to more fully understand the underlying biodegradation processes occurring within the vessels. A range of microbiological and molecular techniques were employed to analyse pathogen survival and assess microbial communities and included; traditional culturing, bioaerosol analysis, 16S rRNA sequencing and automated ribosomal intergenic spacer analysis (ARISA). Carbon footprints were analysed using ISO 14040 Life Cycle Assessment guidelines, greenhouse gas emissions using a portable gas meter and physicochemical and enzyme assays using standard techniques, often based on soil or compost protocols in the absence of specific bioreduction methods. Whilst there is always room for vessel design improvement such as using solar energy and determining loading capacity to reduce foaming, the technology has repeatedly shown to reduce the volume of waste to be ultimately disposed and has gained favour within the livestock industries. Bioreduction has also shown to be biosecure in both laboratory and field settings and under both optimal and sub-optimal conditions. The lack of pathogen proliferation and dispersal meets the requirements of the ABPR for the storage of fallen stock. Therefore, it is recommended that the regulations are updated to include bioreduction for both pig and sheep carcasses.

This thesis describes and assesses the impact of a participatory learning and experimentation process based on the livestock Farmer Field Schools (FFS) approach in Central America. Several organizations have devoted efforts to generating technological improvements for livestock production, such as the implementation of silvopastoral systems (SPS) and intensive livestock practices including silage and hay. However, despite material investments in research and extension for promoting their use, the adoption of those technologies remains limited. In consequence, the livelihoods of farmers and the environmental sustainability of cattle production are compromised, causing negative effects such as contamination of water, degradation of pastures and soils, and poverty. From 2003 to 2008 farmers, local organizations related to livestock production and CA TIE formed an alliance and participated in a regional Degraded Pastures Programme (DEPAPRO). The aim of DEPAPRO was to strengthen livestock stakeholders' capacities for implementing environmentally beneficial livestock production. Mixed methods (quantitative, qualitative and participatory) were combined in three main research stages during fieldwork: (i) FFS documentation; (ii) participatory technology analysis; and (iii) FFS impact assessment. Most of results were structured using the Sustainable Livelihood Approach (SLA); and Community Capitals Framework (CCF). The main effect of DEPAPRO for the stakeholders that participated in the FFS was the strengthening of human capital. Specifically, the stakeholders displayed greater technical knowledge about some intensive and silvopastoral technologies; and methodological skills for organizing FFS. Farmers preferred practices such as improved pastures and live fences because they provided several beneficial impacts, require simple management and were more adaptable to their livelihoods. Analyses showed that further efforts for facilitating the implementation of sustainable livestock production systems are needed. The latter should include the strengthening of assets that have not usually been addressed in agroforestry and rural development projects: namely social and political capitals. Moreover, a search of strategies for creating a supportive policy environment; and mechanisms for funding FFS and the establishment of better practices are also necessary.

Multi-medium pollution control has finally transcended the boundary from its roots in traditional manufacturing industry, and has entered the realm of intensive pig farming. This research has revealed the problems that face pig farmers when confronted by the Integrated Pollution Prevention & Control (IPPC) Directive (1996/61/EC). It has developed approaches that could assist intensive pig farmers in making important choices. A parallel study of the re-licensing of landfill facilities, an industry that is a veteran of licensing, has provided an ideal comparator. The literature on both industries was extensively searched for what was previously known. This has been supported by original research, including interviews with both landfill managers and pig farmers. These interviews were preceded by tours of landfill sites and pig farms - something that is seldom performed within the data collection stage of research where interviews are used. Differences between words and actions became apparent. These were analysed and their motivating factors considered. These discrepancies, evident through this verification process, serves to caution other researchers about the distortions that can arise when interviews alone are used. Identifying these discrepancies is also important because policy is often formulated using information collected though interview-based surveys. It may be the case that policy outcome deficit can result from the difference between words and actions. For decades farming has been moulded by society's desires in a similar vein to a nationalised industry. However, it is not a nationalised industry, but a collection of private individuals, family businesses, and larger companies. Multi-medium pollution control has been tried before. Integrated Pollution Control (IPC) was pioneered in England and Wales in 1991. Comparing the first years of that regime with the experiences that the Environment Agency are currently having reveals that many of the lessons have not been learnt. The funding available to the regulator, and the charges levied against the regulated are negotiated through compromises whereby environmental protection may be the loser. In this study, industry structures have been examined, revealing that the landfill industry is biased towards large operating companies. Re-licensing for the landfill industry is essentially a tightening of existing emission control, with relatively few additions. Landfill operators have the ability to pass costs on. Different experiences have been found between small and large landfill operators. Many small operators will go out of business. In this context it is noted that the structure of the intensive pig farming industry is biased towards smaller operators. Existing literature demonstrates that Small- and Medium-sized Enterprises (SMEs) have difficulty implementing environmental regulation. Through this study, this knowledge has been supplemented by close examination of two industries that have hitherto been omitted from the SME - environmental regulation debate. Industry characteristics are important factors that are here explored in detail, through inter-industry comparisons based upon size and through size comparisons within each industry. Within both industries large size is not just a scaled-up version of a small business. In fact the cultures and organisational structures are different. Essentially, intensive pig farmers have limited choices. Those at the small end of the scale may be able to de-stock and temporarily escape the threshold beyond which strict environmental controls come into play. Many at this scale may decide to retire and abandon pig farming. Alternatives for these farmers include pursuing niche or more specialised markets. Intermediate in size, Family Farming Businesses exhibit characteristics of both large and small businesses. Their future is a little more uncertain as there is a momentum to continue farming - a key characteristic which makes family businesses different. The largest businesses are better placed to implement the controls, or to challenge and to find the least cost compliance route. However, the competition from imports, and an inability to gain more for the meat they produce may force this category to increase the size of operation even further, so as to lower unit costs.

Acid whey is a by-product of the quarg production and arises in large volumes in dairies. A considerable disposal problem arises due to the lack of obtainable proceeds from acid whey utilisation. Additionally, sustainable and energy efficient treatment methods for high strength liquid wastes from dairies cleaning operation are needed to reduce the costs of wastewater treatment. Samples of acid whey and spent cleaning solutions from a quarg cheese production plant were collected. The composition and physical properties were analysed and evaluated against waste treatment process requirements. The occurrence of different waste streams, their volumes and frequencies were also investigated. A laboratory scale membrane nanofiltration plant was designed, and built for investigation of the volume reduction of cleaning process effluents with emphasis to treatment options for the filtration concentrates. The examination of the rheological properties of alkaline CIP wastewaters at different volume reduction ratios clearly shows that these effluents are Newtonian fluids even at high concentrations. The anaerobic biodegradability of acid whey and mixtures containing portions of alkaline CIP wastewaters at different volume reduction ratios was tested. Characteristic process kinetics for acid whey fermentation in batch mode was observed. The occurrence of a second lag-phase in mixtures containing larger portions of acid whey was identified as phase separation- due to rapid acidification of lactose. Anaerobic digestion (AD) was identified as a suitable treatment option for acid whey and alkaline CIP wastewaters. Four anaerobic digester types were designed with regard to their suitability for high strength waste treatment and were built and operated at laboratory scale. The reactors tested were: a) A Continuous Stirred Tank Reactor (CSTR); b) An Anaerobic Membrane Reactor (AMR); c) An Upflow Anaerobic Sludge Blanket (UASB) re- actor; and d) A novel two-stage process design consisting of a combined acidification and crystallization stage and a gaslift driven fluidised bed methanogenic stage. The operation of the AMR process and also of the UASB process with internal circulation and pH-control using alkaline CIP effluents was evaluated at high loading rates of 7.7 g•L-1•d-1 and 10.2 g•L-1•d-1 respective. However, in the experiments it was demonstrated that even with perfect biomass retention the operation of one stage anaerobic digestion at high loading rates caused process upsets. Precipitation and accumulation of milk minerals within the sludge was observed in all one stage experiments. The conclusions drawn from one stage studies led to the design of a novel high-rate diges- tion system to meet the demands of anaerobic digestion of acid whey and effluents from dairy plant cleaning. The design based on different high-rate industrial reactor designs and incorporate the ideas of staging, crystallisation of calcium salts prior to anaerobic di- gestion, fluidised bed and internal circulation reactors, and also jet-loop or gaslift reactors. The performance of the novel system when treating acid whey is comparable to the results of well designed, two-stage digesters treating cheese whey which is easier to digest.

Η Τέφρα Φλοιού Ρυζιού (ΤΦΡ) είναι ένα από τα κυριότερα γεωργικά απόβλητα και προέρχεται από την καύση του φλοιού ρυζιού (ΦΡ) στις ορυζοβιομηχανίες για παραγωγή ενέργειας ή και μείωσης του όγκου των αποβλήτων. Η τέφρα φλοιού ρυζιού αποτελεί περίπου το 18-20% του φλοιού του ρυζιού, ο οποίος αποτελεί περίπου το 20% του ακατέργαστου ρυζιού ενώ συνήθως είναι κρυσταλλική. Καθώς ο παγκόσμιος όγκος της ετήσιας παραγωγής σε ρύζι και κατ’ επέκταση σε τέφρα φλοιού ρυζιού αυξάνεται διαρκώς, εγείροντας περιβαλλοντικά και οικονομικά ζητήματα, η ανεύρεση ενός αποδοτικού και οικολογικού τρόπου εκμετάλλευσης της είναι θέμα μείζονος σημασίας. Παράλληλα, τα υψηλά ποσοστά της ΤΦΡ σε διοξείδιο του πυριτίου την καθιστούν πιθανή πηγή πυριτίου για πολλές εφαρμογές, μία από τις οποίες είναι και οι σύνθεση ζεόλιθων. Στην παρούσα εργασία μελετήθηκε η αξιοποίηση κρυσταλλικής ΤΦΡ στην σύνθεση τεσσάρων τύπων ζεόλιθων και συγκεκριμένα των MFI, FAU, BEA και LTA. Για τον σκοπό αυτό αρχικά χαρακτηρίστηκε η πρώτη ύλη, δηλαδή η ΤΦΡ, τόσο ως προς την χημική της σύσταση και περιεκτικότητα σε άκαυτο άνθρακα όσο και ως προς την κρυσταλλική δομή της. Στη συνέχεια εξακριβώθηκαν οι συνθήκες καύσης του ΦΡ οι οποίες οδηγούν στην μετατροπή από την άμορφη στην κρυσταλλική δομή του διοξειδίου του πυριτίου, η οποία ονομάζεται χριστοβαλίτης. Εφόσον αυτή η κρυσταλλική δομή είναι ακατάλληλη για την παραγωγή ζεόλιθων, μελετήθηκε η δυνατότητα διαλυτοποίησης της ΤΦΡ σε υδατικό διάλυμα καυστικού νατρίου ώστε να καταστραφούν οι κρύσταλλοι και να παραληφθεί άμορφο διοξείδιο του πυριτίου. Για το σκοπό αυτό, επιλέχθηκαν οι μοριακές αναλογίες των πρώτων υλών που οδηγούν στη σύνθεση καθενός από τους τέσσερεις τύπους ζεόλιθων και η ΤΦΡ επεξεργάστηκε με την κατάλληλη αναλογία καυστικού νατρίου σε υδατικό διάλυμα σε διάφορες θερμοκρασίες και συνθήκες. Παρατηρήθηκε κρυστάλλωση του επιθυμητού τύπου ζεόλιθου σε κάθε μία από τις περιπτώσεις που εξετάστηκαν, ενώ το ποσοστό της διάλυσης του χριστοβαλίτη βρέθηκε ότι είχε την σημαντικότερη επίδραση στην απόδοση της διεργασίας και την καθαρότητα του προϊόντος. Ταυτόχρονα διαπιστώθηκε ότι το ποσοστό της διάλυσης του χριστοβαλίτη εξαρτάται κυρίως από την αναλογία μαζών RHA/NaOH και βρέθηκαν οι κατάλληλες τιμές. Καθώς το μεγαλύτερο ποσοστό διαλυμένου χριστοβαλίτη παρατηρήθηκε στην περίπτωση της σύνθεσης του ζεόλιθου LTA, η οποία επιπλέον δεν χρειάζεται οργανικό παράγοντα δομής ούτε υψηλές θερμοκρασίες, επιλέχθηκε να χρησιμοποιηθεί για την μελέτη και την βελτιστοποίηση της διεργασίας. Συγκεκριμένα, εξετάστηκαν διαφορετικές μέθοδοι επεξεργασίας της ΤΦΡ με καυστικό νάτριο, σε μεγάλο θερμοκρασιακό και χρονικό εύρος, ώστε να μελετηθεί η κινητική της διάλυσης του χριστοβαλίτη και να βρεθεί η ενέργεια ενεργοποίησης της. Στη συνέχεια μελετήθηκε η επίδραση της θερμοκρασίας και της διάρκειας στην κρυστάλλωση του ζεόλιθου LTA ώστε να μελετηθεί η κινητική της αντίδρασης και να βρεθεί η ενέργεια ενεργοποίησης της καθώς και οι βέλτιστες συνθήκες απόδοσης της διεργασίας και καθαρότητας του τελικού προϊόντος. Τέλος, εξετάστηκε η επίδραση δύο σημαντικών παραμέτρων, της θερμοκρασίας σύνθεσης και της ταχύτητας ανάδευσης στην ποιότητα του τελικού προϊόντος και βρέθηκαν οι βέλτιστες τιμές τους. Τα αποτελέσματα και τα συμπεράσματα από την παρούσα εργασία, έχουν κατατεθεί στον Οργανισμό Βιομηχανικής Ιδιοκτησίας (Ο.Β.Ι.), για την χορήγηση Διπλώματος Ευρεσιτεχνίας (Δ.Ε.), με αριθμό αίτησης: 20120100391. / Rice husk ash (RHA) is one of the major agricultural wastes and results from the combustion of rice husk (RH) at rice in milling facilities for energy production or waste volumes reduction. Rice husk ash is about 18-20% of the cortex of the rice, which is approximately 20% of raw rice and is usually in its crystalline form. As the global volume of annual production in rice and hence rice husk ash is increasing, raising environmental and economic issues, finding an efficient and ecological way of RHA exploitation is a major issue. In addition, the high rates of RHA on silica render possible silicon source for many applications, one of which is the synthesis of zeolites. In this study, the use of crystalline RHA in the synthesis of four zeolite types, namely MFI, FAU, BEA and LTA was investigated. For this purpose, the raw material, i.e. RHA, was characterized both in terms of its chemical composition and unburned carbon content as well as its crystalline structure. Afterwards, the combustion conditions of RH which lead to the conversion from the amorphous to the crystalline structure of silica, called cristobalite, were determined. Since this crystalline structure is unsuitable for the production of zeolites, the possibility of solubilizing RHA in aqueous sodium hydroxide solution was investigated, in order to destroy the crystals and receive amorphous silica. For this purpose, the molar ratios of the raw materials which would result in the synthesis of each of the four types of zeolites were selected and RHA was treated with the appropriate amount of sodium hydroxide in aqueous solution at various temperatures and conditions. The crystallization of the desired zeolite type in each of the cases examined was verified, while the rate of dissolution of cristobalite was found to have the most significant effect on the process efficiency and the product purity. Simultaneously, it was found that the rate of dissolution of cristobalite mainly depends on the mass ratio of RHA / NaOH and the most suitable values were determined. As the majority of dissolved cristobalite was observed in the case of LTA synthesis, which moreover does not require organic structure directing agent nor high temperatures, it was chosen to be used for the study of design and optimization process. Specifically, several methods of RHA treatment with sodium hydroxide at high temperature and time range were examined, in order to study the kinetics of dissolution of cristobalite and to find the activation energy. Then, the influence of temperature and duration on the crystallization of LTA was examined in order to study the kinetics of the reaction and to determine the activation energy as well as the optimum conditions of the process in terms of efficiency and final product purity. Finally, the effect of two important parameters, the temperature of the synthesis and the stirring speed, on the final product quality was investigated and the optimal values were found. The results and the conclusions of this study, have been submitted to the Hellenic Industrial Property Organization for the grant of Patent with application number: 20120100391.