Modelling of Temperature in Full-scale Systems: a Review of the Biological Heat Generation Within Windrow Composting

Windrow composting is the most common method for organic solid waste treatment. Temperature is an important state variable in modelling, which could be simulated by estimating the change of heat balance components at any moment. Biological heat energy is the most significant term in the heat balance. In this paper biological heat generation of the composting process are examined and their applicability for a full-scale windrow system is evaluated. It is found that, to date, the accuracy of predicting the rate of substrate degradation has been a major challenge. The use of an inductive approach based on either first-order kinetic expression or empirical kinetics relation was found to be more feasible for practical purposes. However a scale-up correction factor for particular processes and types of substrate may need to be further investigated to narrow the discrepancies of kinetic performances between laboratory and full-scale systems

Selective harvest methods and chemical treatment of baled corn residue for utilization in growing calf and dry cow diets

Three studies were conducted to evaluate baled corn residue using selective harvest method and anhydrous ammonia treatments to assess utility in growing calf and dry cow diets. Baled corn residue was harvested using conventional rake-and-bale (CONV) method, or harvested using the New Holland Cornrower in which either eight rows (8ROW), or two rows (2ROW) of corn stalks were chopped into the windrow with tailings. Bales were either not treated or ammoniated at 5.5% DM. When fed to wether lambs in a mixed ration (65% residue, 30% wet corn gluten feed) to determine digestibility, the 2ROW residue had greater apparent DM, NDF, ADF digestibility, as well as in vitro DM and OM digestibility than either CONV and 8ROW, which were not different. Ammoniation resulted in a 20 to 26% increase in apparent DM, OM, NDF, and ADF digestibility and digestible energy content of the residue. When corn residue was baled as CONV, 2ROW, or using the EZ-Bale system (EZB) with a disengaged combine spreader (treated or ammoniated at 3.7% DM) and fed to growing cattle (65% with 30% wet distillers grains), only the 2ROW method increased (P \u3c 0.01) ADG (1.06 kg/d) compared to CONV (0.96 kg/d) and EZB (0.99 kg/d). Ammoniation increased (P \u3c 0.01) ADG from 0.75 to 1.26 kg/d and increased (P \u3c 0.01) G:F from 0.158 to 0.179. Selective harvest methods altered (P ≤ 0.01) plant part proportions, and ammoniation differentially increased the digestibility among the various plant parts. A third study used the same treatments fed as whole bales to dry cows and measured intake, waste, and refusals. Ammoniation increased (P \u3c 0.01) DM intake by 18% and waste including refusals ranged between 29.3 and 42.3% of offered DM. Ammoniated residues had sufficient CP to meet cow protein requirements throughout gestation, but only the ammoniated 2ROW and EZB residue had enough DOM to meet gestation energy requirements. Ammoniated corn residue increases digestibility and improves animal performance, and these effects can be enhanced when combined with some selective harvest methods due to changes in plant part proportion and increased susceptibility of cob to ammoniation. Advisor: Mary E. Drewnosk

Selective harvest methods and chemical treatment of baled corn residue for utilization in growing calf and dry cow diets

Three studies were conducted to evaluate baled corn residue using selective harvest method and anhydrous ammonia treatments to assess utility in growing calf and dry cow diets. Baled corn residue was harvested using conventional rake-and-bale (CONV) method, or harvested using the New Holland Cornrower in which either eight rows (8ROW), or two rows (2ROW) of corn stalks were chopped into the windrow with tailings. Bales were either not treated or ammoniated at 5.5% DM. When fed to wether lambs in a mixed ration (65% residue, 30% wet corn gluten feed) to determine digestibility, the 2ROW residue had greater apparent DM, NDF, ADF digestibility, as well as in vitro DM and OM digestibility than either CONV and 8ROW, which were not different. Ammoniation resulted in a 20 to 26% increase in apparent DM, OM, NDF, and ADF digestibility and digestible energy content of the residue. When corn residue was baled as CONV, 2ROW, or using the EZ-Bale system (EZB) with a disengaged combine spreader (treated or ammoniated at 3.7% DM) and fed to growing cattle (65% with 30% wet distillers grains), only the 2ROW method increased (P \u3c 0.01) ADG (1.06 kg/d) compared to CONV (0.96 kg/d) and EZB (0.99 kg/d). Ammoniation increased (P \u3c 0.01) ADG from 0.75 to 1.26 kg/d and increased (P \u3c 0.01) G:F from 0.158 to 0.179. Selective harvest methods altered (P ≤ 0.01) plant part proportions, and ammoniation differentially increased the digestibility among the various plant parts. A third study used the same treatments fed as whole bales to dry cows and measured intake, waste, and refusals. Ammoniation increased (P \u3c 0.01) DM intake by 18% and waste including refusals ranged between 29.3 and 42.3% of offered DM. Ammoniated residues had sufficient CP to meet cow protein requirements throughout gestation, but only the ammoniated 2ROW and EZB residue had enough DOM to meet gestation energy requirements. Ammoniated corn residue increases digestibility and improves animal performance, and these effects can be enhanced when combined with some selective harvest methods due to changes in plant part proportion and increased susceptibility of cob to ammoniation. Advisor: Mary E. Drewnosk

Climate Change and Environmental Sustainability- Volume 5

This volume of Climate Change and Environmental Sustainability covers topics on greenhouse gas emissions, climatic impacts, climate models and prediction, and analytical methods. Issues related to two major greenhouse gas emissions, namely of carbon dioxide and methane, particularly in wetlands and agriculture sector, and radiative energy flux variations along with cloudiness are explored in this volume. Further, climate change impacts such as rainfall, heavy lake-effect snowfall, extreme temperature, impacts on grassland phenology, impacts on wind and wave energy, and heat island effects are explored. A major focus of this volume is on climate models that are of significance to projection and to visualise future climate pathways and possible impacts and vulnerabilities. Such models are widely used by scientists and for the generation of mitigation and adaptation scenarios. However, dealing with uncertainties has always been a critical issue in climate modelling. Therefore, methods are explored for improving climate projection accuracy through addressing the stochastic properties of the distributions of climate variables, addressing variational problems with unknown weights, and improving grid resolution in climatic models. Results reported in this book are conducive to a better understanding of global warming mechanisms, climate-induced impacts, and forecasting models. We expect the book to benefit decision makers, practitioners, and researchers in different fields and contribute to climate change adaptation and mitigation

A new control strategy for composting process based on the oxygen uptake rate

Up to now different control strategies to supply the oxygen requirements to the composting process have been studied. All of them seek for the biological activity optimization. In general, temperature and oxygen content are identified as the key parameters to assess the microbial activity. For this reason, the most favorable range of temperature and oxygen content for composting has frequently been studied and used as controllers' set points. On contrast, no previous works have studied the feasibility of oxygen supply according to the biological activity during the process, measured as oxygen uptake rate. In this field, a new automatic composting controller has been developed using the oxygen uptake rate measure as the measured variable. After setting up and to start-up this new technique, two pilot composting trials were undertaken with municipal solid waste. Oxygen, temperature and cyclic controllers were also implemented and tested in the composting of the same waste, in order to compare the results and to determine what the optimum system is. The four systems studied had similar temperature profiles, whereas except for the new controller, the oxygen content was constantly oscillating during most part of the process due to severe airflow changes. Through all the most relevant parameters determined, it can be observed that the new controller offers the most optimum system performance, since with low energy consumption a higher total oxygen uptake is achieved and, in consequence, the most stable end-product is obtained. Hence, the oxygen uptake rate controller is recommended for the airflow regulation in composting systems with automatic control

Composting modelling : towards a better understanding of the fundamentals, applications for enhanced nutrient recycling, greenhouse gas reduction, and improved decision-making

Cette thèse de doctorat vise à consolider, développer et appliquer nos connaissances sur la modélisation du compostage, dans le but de fournir des informations, des outils et des perspectives accessibles et utilisables pour les chercheurs et les décideurs. L'espoir est que les travaux développés tout au long de cette thèse puissent aider à optimiser les procédés de compostage, notamment en réduisant les émissions de gaz à effet de serre (GES) et en améliorant le recyclage des nutriments. A ce titre, la thèse est divisée en trois phases : (1) la phase 1 est une consolidation et un développement des notions fondamentales de la modélisation du compostage, (2) suivie de la phase 2, où la modélisation de la perte de nutriments et des émissions de GES est étudiée, (3) avec la phase 3 qui est axée sur la manière d'assurer que ce travail puisse être utilisé par les décideurs et acteurs dans le milieu de compostage. Dans la première phase, une revue complète et systématique de l'ensemble de la littérature sur la modélisation du compostage a été entreprise (chapitre 2), cherchant à fournir une meilleure compréhension du travail qui a été fait et sur la direction des travaux futurs. Ceci a été suivi d'une étudie détaillée des approches de modélisation cinétique actuelles, notamment par rapport aux facteurs de corrections cinétiques appliqués à travers le domaine (chapitre 3). La phase 2 s'est ensuite focalisée sur les notions spécifiques relatives aux émissions de GES et aux pertes de nutriments lors du compostage, et à la modélisation de ces phénomènes. Cette thèse présente les réacteurs expérimentaux et le plan conçu pour suivre et évaluer le processus de compostage (chapitre 4), ainsi que le modèle de compostage compréhensif développé pour prédire avec précision les émissions et la transformation des nutriments pendant le compostage (chapitre 5). Enfin, la phase 3 visait à rendre ces informations facilement et largement utilisables. Cela a commencé par une évaluation des meilleures pratiques pour développer des modèles et des systèmes d'aide à la décision pour la prise de décision environnementale (chapitre 6), suivi par le développement de nouvelles approches de modélisation cinétique simples (chapitre 7), culminant avec le développement, l'ajustement paramétrique et la validation d'un modèle de compostage parcimonieux (chapitre 8). Grâce à ce travail, une base consolidée de l'état actuel de la modélisation du compostage a été développée, suivie par l'exploration et le développement de connaissances et d'outils à la fois fondamentaux et applicables.This PhD thesis aims consolidating, developing, and applying our knowledge on composting modelling, with the goal of providing accessible and usable information, tools, and perspectives for researchers and decision-makers alike. The hope is that the work developed throughout this dissertation can help in optimizing composting, notably by reducing greenhouse gas (GHG) emissions and improving nutrient recycling. As such, the thesis is divided into three phases: (1) phase 1 is a consolidation and development of the fundamentals of composting modelling, (2) followed by phase 2, where the modelling of nutrient loss and GHG emissions is investigated, (3) with phase 3 focusing on how to ensure that this work can be used by decision-makers. In the first phase, a comprehensive and systematic review of the entirety of the literature on composting modelling was undertaken (chapter 2), seeking to provide a better understanding on the work that has been done and guidance on where future work should focus and how it should be approached. This review then raised some interesting questions regarding modelling approaches, notably regarding modelling of composting kinetics, which was studied in detail through the evaluation of current modelling approaches (chapter 3). Phase 2 then focused on the specific notions relating to GHG emissions and nutrient loss during composting, and how to model these phenomena. This section starts with a presentation of the experimental reactors and plan designed to monitor and evaluate the composting process (chapter 4), followed by the comprehensive composting model developed to accurately predict emissions and nutrient transformation during composting (chapter 5). Finally, phase 3 aimed to make this information easily and widely usable, especially for decision-makers. This started with a review on the best practices to develop models and decision support systems for environmental decision-making (chapter 6), followed by the development of novel simple kinetic modelling approaches (chapter 7), culminating with the development, calibration, and validation of a parsimonious composting model (chapter 8). Through this work, a consolidated basis of the current state on composting modelling has been developed, followed-up by the exploration and development of both fundamental and applicable knowledge and tools

Life Cycle Assessment (LCA) of Light-weight Eco-composites

The environmental profiles of novel wheat based foam materials were investigated in this thesis using Life Cycle Assessment (LCA) methods. The LCAs were developed using primary data collected from industrial sources combined with new laboratory experiments supplemented with secondary data from publicly available sources. Laboratory research was conducted to obtain important missing data on WBFs for the LCA modelling, including physico-chemical parameters, biodegradability and energy recovery under anaerobic digestion conditions. Contribution analysis suggested that the emissions evolved from the wheat agro-ecosystem and PVOH production, together with the energy and infrastructure involved in WBF production were the major contributors to the environmental burdens of the WBF life cycle in most impact categories. The atmospheric emissions resulting from WBF degradation at the end-of-life also emerged as another important contributor to environmental impact. Amongst the diverse 'end-of-life‘ scenarios examined, AD and home composting were suggested to be the optimum choices for WBF waste treatment. To address the question 'is there a general environmental advantage for WBFs over petrochemical polymers', case studies were applied to compare the performance of WBFs with HDPE/LDPE/EPS in various applications. Further exploration of potential biopolymer foam materials was undertaken by study of two additional foams derived from potato and maize starches. The results suggested that this group of starch-PVOH blended biopolymers offer environmentally superior options to LDPE in thermal packaging applications. However, this is not the case for other applications, where the outcome of comparisons between starch-PVOH biopolymers and HDPE/EPS varied with the specific application examined. A hierarchy of critical parameters for LCA-based decision-making on WBFs is suggested as a general outcome of this research. This research discusses two N2O modelling approaches and presents a method to expand the system boundary by integrating the process-oriented model DNDC for field emissions into the LCA. Sensitivity analysis suggests that the environmental profiles of agricultural products are influenced substantially by the system boundary definition. Furthermore, it suggests that the 'general rule‘ in LCA practice by applying an empirical model or a default emission factor (EF) could deliver unreliable LCA findings. This study also evaluated the sensitivity of the LCA results to methodology and data variations and quantified the uncertainties in the LCA outcomes arising from uncertainty in the inventory and data variability. This has led to an increase in confidence in the LCA findings. At the same time it indicates the areas where improvements in data or methods are needed in order for robust conclusions to be drawn and unbiased information to be delivered e.g. the methodological rigidity of characterization models, the IPCC Tier 1 EF uncertainty range