Does community scale composting produce a viable outcome? Some physical and chemical properties of green waste composts produced in the Faculty of Sciences campus

A compostagem pode ser definida como o processo de biodegradação de resíduos orgânicos realizado por comunidades microbianas em condições aeróbias, sendo uma forma sustentável de gerir estes resíduos no contexto de uma economia mais circular. Neste trabalho foi analisado um sistema de compostagem a uma escala comunitária. Para cada pilha, as matérias-primas e os compostos foram pesados e as temperaturas monitorizadas semanalmente. Os parâmetros físico-químicos foram analisados, bem como o teor de inertes, e foram realizados testes fitotóxicos. Os resultados mostraram que as amostras de composto cumpriam a maioria dos requisitos definidos pelas normas legais portuguesas em relação à qualidade dos mesmos, exceto no teor de humidade e de pedras. No entanto, os testes de maturação indicaram que todos os produtos finais estavam consistentemente maturados. Os resultados obtidos demonstraram que é possível gerir os resíduos orgânicos dos espaços verdes através da compostagem local, com benefícios ao nível ecológico e social; Composting is the biodegradation process of organic substrates carried out by microbial communities, under aerobic conditions. It is a sustainable way to manage biodegradable waste within a context of a more circular economy. In this work, a community-scale green waste composting system was under study. For each pile, feedstocks and composts were weighted and temperatures were monitored weekly. Physicochemical parameters were analysed, phytotoxic tests were performed and the inert material content was assessed. Results showed that the compost samples fulfilled the majority of the requirements set by the Portuguese statutory standards for compost quality, except for moisture and stone content. However, maturity tests indicated all final products as consistently mature. Additionally, the particle size dimensions of the final composts were suitable for both of the main uses. The results showed that is possible to manage organic waste from the green areas through local composting with ecological and social benefits associated

An Overview of Dairy Cattle Models for Predicting Milk Production: Their Evolution, Evaluation, and Application for the Agricultural Model Intercomparison and Improvement Project (AgMIP) for Livestock.

The contemporary concern about anthropogenic release of greenhouse gas (GHG) into the environment and the contribution of livestock to this phenomenon have sparked animal scientists’ interest in predicting methane (CH4) emissions by ruminants. Focusing on milk production, we address six basic nutrition models or feeding standards (mostly empirical systems) and five complex nutrition models (mostly mechanistic systems), describe their key characteristics, and highlight their similarities and differences. Four models were selected to predict milk production in lactating dairy cows, and the adequacy of their predictions was measured against the observed milk production from a database that was compiled from 37 published studies from six regions of the world, totalling 173 data points. We concluded that not all models were suitable for predicting predict milk production and that simpler systems might be more resilient to variations in studies and production conditions around the world. Improving the predictability of milk production by mathematical nutrition models is a prerequisite to further development of systems that can effectively and correctly estimate the contribution of ruminants to GHG emissions and their true share of the global warming even

A decision support system for integrated semi-centralised urban wastewater treatment systems

The importance of adequate water supply and sanitation infrastructure as cornerstones for the development of civilizations is undeniable. Although a strategy based on centralised infrastructure has proven to be successful in the past, in some circumstances such conventional systems are inappropriate for future needs. A Semi-centralised Urban Wastewater Treatment System (SUWWTS) may be considered a viable sustainable urban water management solution to promote water security. A SUWWTS merges regulations of traditional centralised systems with the concepts of close-loop and resource recovery of decentralised systems. However, research on the design and feasibility of implementing semi-centralised systems is in its infancy. This Thesis is a first attempt to articulate the complexity, to systematize and to automatize the design of a SUWWTS. Here we show a novel method, referred to as framework, for the development of SUWWTS with allowance for the socio-economic and geographic context of any urban area. To demonstrate the proposed framework a Decision Support System (DSS) was developed; its output is a recommended design comprised of several wastewater treatment plants, their respective technology, and their associated sewerage and reclaimed water distribution networks. The results demonstrate the capabilities and the usefulness of the DSS; it applies the design engineers’ subjective preferences, such as regional technological inclinations and implementation strategies. The results from a feasibility study on the city of Rio de Janeiro validated and demonstrated how the DSS can be used to assist decision-makers. This Thesis discusses the framework, the DSS and the demonstration case. Overall, it will hopefully help both other researchers and practitioners by contributing to the discussion on how to promote urban water security, to decrease urban areas’ dependency on ecosystem services whilst delivering better social welfare

Strategic Research Agenda for organic food and farming

The TP Organics Strategic Research Agenda (SRA) was finalised in December 2009. The purpose of the Strategic Research Agenda (SRA) is to enable research, development and knowledge transfer that will deliver relevant outcomes – results that will contribute to the improvement of the organic sector and other low external input systems. The document has been developed through a dynamic consultative process that ran from 2008 to 2009. It involved a wide range of stakeholders who enthusiastically joined the effort to define organic research priorities. From December 2008 to February; the expert groups elaborated the first draft. The consultative process involved the active participation of many different countries. Consultation involved researchers, advisors, members of inspection/certification bodies, as well as different users/beneficiaries of the research such as farmers, processors, market actors and members of civil society organisations throughout Europe and further afield in order to gather the research needs of the whole organic sector

The Austrian Carbon Database (ACDb) Study - Overview [Revised 28 October 2003]

This is the final overview report of the Austrian Carbon Database (ACDb) Study, which pursues three main objectives: (1) to support the Austrian Carbon Balance Model (ACBM) II; (2) to internationalize the Austrian carbon analysis and to place Austrias carbon accounting within an international science and policy context focusing on the UN Framework Convention on Climate Change (FCCC); and (3) to provide good practice guidance in consideration of Full Carbon Accounting (FCA) rather than Partial Carbon Accounting (PCA). The Study is divided into two phases, a deductive and an inductive research phase. The deductive research phase builds upon the theoretical insights gained during the ACDb Study and addresses Objective 2 (Internationalization). The inductive research phase builds upon the generalized experiences from working with uncertainties in building the ACDb and addresses Objectives 1 (ACBM II Support) and 3 (Good Practice Guidance). The ACDb is a carbon consistent database for Austria that acknowledges FCA. It focuses on publicly available, including measured, data around 1990 and attributes special importance to the direct and transparent understanding of both first (mean values) and second statistical moments (uncertainties). The ACDb does not replace existing, officially agreed and widely accepted, Austrian databases but provides a thematically less detailed, however, carbon consistent standard that allows to quantify the uncertainties underlying these databases when using them in a wider (Austrian-integrated) context than traditionally done. The focus of the Study is on conclusions that are generally valid and are not only specific for Austria. Based on our deductive and inductive research, we conclude that the Kyoto Protocol and the way national emissions are inventoried urgently need fundamental as well as methodological improvements, more than ever before

Modelling dairy grazing systems: an integrated approach

This thesis describes a management décision-support system for dairy grazing systems based on simulation and multiple criteria decision-making (MCDM) models.Appropriate selection of holistic management strategies for livestock farming systems requires: 1) understanding of the behaviour of, and interrelations between, the different parts of the system, 2) knowledge of the basic objectives of the decision-maker managing such enterprise, and 3) understanding of the system as a whole in its agro-ecoregional context.Increasing economic and environmental pressures on livestock production systems have created the need to re-evaluate current management practices and to study new alternatives to ensure their sustainability. As a consequence, the demand for décision-support systems based on mathematical models has increased in the past years. Validated simulation models provide cost-effective means to represent the dynamics of the system and its components, while MCDM models allow for appropriate selection of resource allocation strategies depending on the different objectives and management 'styles' of particular individuals. Integration of both mechanisms provides the necessary elements for efficient décision- support at farm or ecoregional level.A décision-support system based on these techniques has been built to represent pastoral dairy production systems. The biological aspects (grass growth; grazing; digestion and metabolism; animal performance, and herd dynamics) are represented by simulation studies under a variety of management regimes. The outputs from the simulation runs (such as pasture utilisation, stocking rates, milk yields, fertilizer use, etc.) are used as data input to the MCDM models, and the latter have been used to select the management strategies which make the most efficient use of the farm's resources (i.e. land, animals, pastures).Examples are given with reference to highland dairy farming in Costa Rica. Nevertheless, the model frameworks are generic and can be adapted to different farming systems or ruminant species. The effect of model formulation and sensitivity, different decision-maker objectives, and/or activity or constraint definitions on management strategy selection are analysed. Future areas of research to expand this work to other livestock farming systems and to integrate other related disciplines into this décision-support framework are also discussed

Techno-economic and environmental assessment of gas turbines utilizing biofuels

The continued global reliance on fossil fuels with impact on resource depletion, human health, atmospheric pollution and environmental degradation has necessitated a global drive to integrate renewable fuels such as biodiesels. Biodiesels are described as “fuels composed of fatty acid methyl or ethyl esters and obtained from vegetable oils or animal fats”. Their use in energy generation could diversify the world’s energy mix, reduce fossil fuel dependence, reduce emissions and energy cost to bring about other economic benefits, especially for developing economies and rural communities with lack of adequate access to modern energy. A techno-economic and environmental life cycle assessment is however required to ensure that these fuels are fit for use in engines and meet any regulatory standard and sustainability criteria. This thesis has evaluated the use of Jatropha- and microalgae-biodiesel for power generation in two industrial gas turbines with open and combined cycle configuration. This was achieved using a techno-economic and environmental life cycle impact assessment framework. Comparative fuel assessments have been carried out between biodiesels and fossil fuels. Furthermore, the concept of microbial fuel degradation was examined in gas turbines. The thesis have identified Jatropha biodiesel as a worthwhile substitute for conventional diesel fuel, because it has close performance and emission characteristics to conventional diesel fuel with added advantage of being renewable. The consequent displacement of conventional diesel fuel with Jatropha biodiesel has significant environmental benefits. For economic viability and sustainability of gas turbine operated power plants, energy producers require a minimum monetary amount to recover the added cost of operating 100% Jatropha biodiesel. Other integration mechanisms are also available for utilizing the fuel in engines without compromising on plant’s economic performance. In worst case scenarios, where there are no government incentives, local conditions such as high life cycle cost of electricity, open opportunities for distributed and independent power generation from renewable fuels like Jatropha-biodiesel. Furthermore, this thesis has identified salient energy conversion processes that occur in gas turbine fuels, especially with biodiesels and developed a bio-mathematical model, Bio-fAEG to simulate these processes in gas turbines. This platform is a first step in quantifiable assessment and could enable a better understanding of microbial initiated processes