The entire comparative estimation comprises four sections: 1. Embodied environmental implications of different structural systems of wooden buildings; 2. Embodied ecological efficiency of diverse constructions composed of various materials; 3. LCA of building models comprising equivalent thermal performance; 4. LCA of building models exhibiting similar seismic behaviour. First, the LCA results for thirty realised buildings are analysed based on the inventory of each project. This evaluation is intended to quantify and compare the embodied environmental burdens caused by different structural systems of timber houses. The second section is a comparative evaluation of the embodied ecological impacts caused by different materials, when used in the same construction. This study aims to investigate the ecological efficiency of various materials in the form of whole structures. With regard to making a compatible and reasonable LCA comparison, however, the appraisal needs a more scientific framework. In order to address this insufficiency, the third and fourth LCA studies are carried out. The third section involves various buildings made of different materials but providing equivalent thermal performance. Within this estimation, the thermal performance of a building is simply represented by the thermal inertia of its outer walls. Constructions composed of alternative envelopes are established and LCA based on the inventories of these structures are carried out. The fourth section examines three structures composed of three building materials but exhibiting similar seismic behaviour. In this study, the horizontal stiffness of the entire building against earthquakes indicates its seismic performance. The simulation develops alternative multi-storey buildings according to the seismic performance. The environmental impacts of the three buildings are quantified and compared. Both the third and fourth sections take the recycling scenarios into account. The impact of disposal after the end-of-life and the contribution from reuse and recovery are integrated into the overall impact assessment. Defining the system boundary and scope is essential for LCA studies. Normally, LCA framework refers to a ‘from-cradle-to-grave’ scenario, including the manufacturing, utilisation and dismantling phases. In the studies here, however, the estimation is focused on the production and recycling stages, without the results for utilisation and maintenance. This appraisal is the so-called ‘from-cradle-to-gate’ plus ‘from-gate-to-grave’ system. Compared to former research, this dissertation raises a couple of innovative contributions to the sustainability appraisals of constructions: 1. The scopes are focused on the structural part of buildings, considering the congruent system boundary for LCA. 2. A series of LCAs compare various building materials in the form of construction, integrating diverse aspects about buildings like thermal and seismic performance. 3. These LCAs are based on consistent prerequisites and make it possible to compare the results comprehensively. 4. In addition to embodied implications, these LCA quantify the contribution from material recycling. 5. This study divides the timber buildings according to their structural systems and estimates them individually. / Die vergleichende Bewertung der Umweltleistung mehrgeschossiger Wohnbauten umfasst vier Abschnitte: 1. Ökologische Auswirkungen der Bereitstellung und Bearbeitung von Holz für verschiedene Tragsysteme; 2. Material- und herstellungsinduzierte (graue) Umwelteffizienz von verschiedenen Materialien und Bauweisen; 3. Ökobilanzierung von Gebäuden mit gleichen thermischen Eigenschaften; 4. Ökobilanzierung von Gebäuden mit ähnlichem seismischen Verhalten. Zunächst werden die Ergebnisse der Ökobilanz für dreißig realisierte Bauten auf der Grundlage der Sachbilanzen analysiert. Diese Auswertung vergleicht und quantifiziert die materialbezogene Umweltbelastung für verschiedene Tragsysteme mehrgeschossiger Wohnbauten aus Holz. Der zweite Abschnitt vergleicht die ökologischen Auswirkungen verschiedener Baustoffe, wobei jeweils der gleiche Konstruktionstyp zugrunde gelegt wird. Das Ziel dieser Studie ist die Untersuchung der Umwelteffizienz unterschiedlicher Materialien auf der Ebene der Gebäudeteile. In Hinblick auf die Kompatibilität und Plausibilität der Ökobilanz wird mit der dritten und vierten LCA ein einheitlicher Bewertungsansatz geschaffen. Der dritte Abschnitt handelt von verschiedenen Gebäudetypen mit gleichem Wärmestandard aber unterschiedlichen Baustoffen, wobei die Wärmeeffizienz vereinfachend durch den Wärmedurchgangswiderstand der Außenwände erfasst wird. Es werden Baukonstruktionen mit alternativen Gebäudehüllen entwickelt und auf der Grundlage der Sachbilanzen ökologisch bewertet. Der vierte Abschnitt untersucht drei Strukturen aus verschiedenen Baustoffen mit ähnlichem seismischen Verhalten. Diese Studie verwendet die horizontale Steifigkeit des Gebäudes gegen Erdbebenerschütterungen als Indikator für die seismische Leistungsfähigkeit. Auf der Basis dieses Indikators werden konstruktive Alternativen für mehrgeschossige Gebäuden entwickelt und deren Umweltwirkungen quantitativ ermittelt. Sowohl im dritten als auch im vierten Abschnitt werden unterschiedliche Recyclingszenarien berücksichtigt. Die Auswirkungen auf die Umwelt, die nach der Nutzungsdauer infolge der Abfallbeseitigung, des Materialrecycling oder die Wiederverwendung entstehen, werden in die gesamte Umweltwirkungsabschätzung integriert. Die Festlegung der Systemgrenzen und der Umfang der Betrachtung ist für die Ökobilanz unerlässlich. Normalerweise betrachten diese alle Lebenszyklusphasen eines Produkts, einschließlich Herstellung, Nutzung und Recyclings („from-cradle-to-grave“). Die hier betrachteten Untersuchungen beschränken sich jedoch auf die Phasen der Produktion und des Recyclings. Umweltauswirkungen infolge der Nutzung und Wartung des Gebäudes werden nicht berücksichtigt ( „from-cradle-to-gate“ und „from-gate-to-grave“). Im Vergleich mit früheren Forschungsergebnissen arbeitet diese Dissertation innovative Beiträge zur Umweltbewertung von Baukonstruktionen heraus: 1. Der Rahmen der Untersuchung erstreckt sich auf die Bauteile der Gebäudestruktur, was zu einer einheitlichen Systemgrenze für die Ökobilanzen führt. 2. Die Datenreihen der Ökobilanzen vergleichen verschiedenartige Baumaterialien auf der Ebene von Gebäudeteilen unter verschiedenen Aspekten. 3. Diesen Ökobilanzen liegen einheitliche Voraussetzungen zugrunde. Dadurch ist es möglich, die Ergebnisse umfassend zu vergleichen. 4. Neben den material- und herstellungsinduzierten Umweltauswirkungen quantifizieren diese Ökobilanzen direkt den Beitrag des Materialrecyclings. 5. Die Arbeit klassifiziert die mehrgeschossigen Holzbauten nach Tragsystemen und bewertet diese individuell.

Poly butylene succinate (PBS) is a biodegradable plastic polymer that has physical and mechanical properties similar to common petroleum plastics like polypropylene (PP) and polyethylene (PE). PBS may be produced from petroleum or bio-based feedstocks, or by a hybrid combination of petroleum and bio-based resources. Producers are reducing content of petroleum components used for the production of PBS, and by doing so are seeking potential environmental performance improvements. In this study, ???hybrid??? PBS refers to the production of PBS polymer from bio-based succinic acid (SAC) sourced from sorghum and petroleum-based 1, 4-butanediol (BDO). Given its biodegradability, PBS is commercially used for compostable bags and agricultural mulching film applications. A recent study in Ontario identified composite materials made with PBS blended with natural fibres like switchgrass (SG) as promising for applications in automotive products. Such novel composite materials are touted as potential bio-based alternatives to conventional petroleum-based plastics. Of the few studies that have considered the environmental performance of PBS materials, none have assessed the potential environmental impacts of a hybrid PBS composite. Therefore, this study undertook a life cycle assessment (LCA) of SG reinforced hybrid PBS composite (hybrid composite). LCA is an environmental management technique that is used to assess environmental aspects (inputs and outputs) and potential environmental impacts of a product or service throughout its life cycle. The analysis considered a cradle-to-gate system boundary and evaluated eleven environmental performance indicators. The environmental performance of the hybrid composite was compared to a conventional glass fibre (GF) reinforced polypropylene (PP) composite (baseline composite), a material that is widely used in automotive components. Results showed that the production of the hybrid composite in comparison to the baseline composite decreased potential impact for most of the assessed indicators: cumulative energy demand by 40%, waste heat by 23%, global warming potential by 35%, smog by 2%, carcinogens by 54%, non-carcinogens by 172%, respiratory effects by 22% and ecotoxicity by 45%. Increases in the values of impact indicators were apparent for ozone depletion, acidification, and eutrophication by 43%, 16%, and 322%, respectively. Analysis revealed that dominant influences on results were not related directly to the bio-based make-up. Rather, the biggest influence on the environmental performance of composite production were the sources of heat used in petroleum-based materials, the energy mix in electricity for bio-based materials, the type of reinforcing fibre and the co-product treatment methodology used. The study helps fill a gap in knowledge regarding bio-based chemicals and hybrid biodegradable plastic composites, and points to opportunities for future research on feedstocks for industrial composite materials. The importance of this study is that it helps to identify the environmental strengths and weaknesses associated with the production of the hybrid composite specifically, and bio-based materials more generally. It points to alternative material substitution options for use in the automotive industry. In this study, life cycle assessment exemplifies multidisciplinary methodologies, which seek to traverse the boundaries between the social and natural sciences and disciplines to support more sustainable policy decisions for a bio-economy. The systematic nature and the widely applicable consequences of this LCA study have the potential to contribute to industrial and business management, and reach the public policy arena in an effort to drive environmental and social change.

The four papers of this dissertation explore themes related to waste prevention, the system boundaries, functional units and scale of life cycle assessments (LCAs) of municipal solid waste (MSW) management, as well as the transparency and consistency of the application of LCA methods. The first paper is a comparative analysis of the methodological choices and transparency of 20 LCAs of MSW that were recently published in peer-reviewed journals, and includes a comparison of their midpoint level impact values using statistical indicators. The second paper proposes a conceptual model, designated WasteMAP (Waste Management And Prevention), for evaluating LCAs of MSW which incorporate waste prevention. In WasteMAP, waste prevention through dematerialization is viewed as analogous to waste treatments so long as it does not affect the functional output (product services) of MSW-generating product systems. Papers 3 and 4 comprise the WasteMAP LCA case study. Paper 3 depicts product LCAs of wine and spirit packaging (conventional, lightweight and refillable, each type generating different quantities of waste) at the scale of the individual package and the municipality. At the municipal scale, the LCAs address impacts from the wine and spirit packaging supplied in the City of Toronto, Canada in 2008, and a waste prevention scenario which substitutes lighter weight and reusable containers. The lowest endpoint level impacts out of the five container types studied were associated with refillable containers and aseptic cartons. Paper 4 addresses the Toronto MSW management system and applies the WasteMAP model to allow for the comparison, on a functionally equivalent basis, of the LCA results of a reference scenario, based on 2008 data, with a scenario incorporating six types of waste prevention activities (prevention of unaddressed advertising mail, disposable plastic bags, newspapers, lightweight and refillable wine and spirit packaging, and yard waste). The findings highlight the benefits of waste prevention, and the relative significance of the decision to account for recycled content when modelling waste prevention. The endpoint level impact assessment results using the ReCiPe and Impact 2002+ evaluation methods are in keeping with the assumption in the waste hierarchy that waste prevention has a superior environmental performance.

The four papers of this dissertation explore themes related to waste prevention, the system boundaries, functional units and scale of life cycle assessments (LCAs) of municipal solid waste (MSW) management, as well as the transparency and consistency of the application of LCA methods. The first paper is a comparative analysis of the methodological choices and transparency of 20 LCAs of MSW that were recently published in peer-reviewed journals, and includes a comparison of their midpoint level impact values using statistical indicators. The second paper proposes a conceptual model, designated WasteMAP (Waste Management And Prevention), for evaluating LCAs of MSW which incorporate waste prevention. In WasteMAP, waste prevention through dematerialization is viewed as analogous to waste treatments so long as it does not affect the functional output (product services) of MSW-generating product systems. Papers 3 and 4 comprise the WasteMAP LCA case study. Paper 3 depicts product LCAs of wine and spirit packaging (conventional, lightweight and refillable, each type generating different quantities of waste) at the scale of the individual package and the municipality. At the municipal scale, the LCAs address impacts from the wine and spirit packaging supplied in the City of Toronto, Canada in 2008, and a waste prevention scenario which substitutes lighter weight and reusable containers. The lowest endpoint level impacts out of the five container types studied were associated with refillable containers and aseptic cartons. Paper 4 addresses the Toronto MSW management system and applies the WasteMAP model to allow for the comparison, on a functionally equivalent basis, of the LCA results of a reference scenario, based on 2008 data, with a scenario incorporating six types of waste prevention activities (prevention of unaddressed advertising mail, disposable plastic bags, newspapers, lightweight and refillable wine and spirit packaging, and yard waste). The findings highlight the benefits of waste prevention, and the relative significance of the decision to account for recycled content when modelling waste prevention. The endpoint level impact assessment results using the ReCiPe and Impact 2002+ evaluation methods are in keeping with the assumption in the waste hierarchy that waste prevention has a superior environmental performance.

Environmental metrics play a significant role in behavioural change, policy formation, education, and industrial decision-making. Life Cycle Assessment (LCA) is a powerful framework for providing information on environmental impacts, but LCA data is under-utilized, difficult to access, and difficult to understand. Some of the issues that are required to be resolved to increase relevancy and use of LCA are accessibility, validation, reporting and publication, and transparency. This thesis proposes that many of these issues can be resolved through the application of open frameworks for LCA software and data. The open source software (OSS), open data, open access, and semantic web movements advocate the transparent development of software and data, inviting all interested parties to contribute. A survey was presented to the LCA community to gauge the community’s interest and receptivity to working within open frameworks, as well as their existing concerns with LCA data. Responses indicated dissatisfaction with existing tools and some interest in open frameworks, though interest in contributing was weak. The responses also pointed out transparency, the expansion of LCA information, and feedback to be desirable areas for improvement. Software for providing online LCA databases was developed according to open source, open data, and linked data principles and practices. The produced software incorporates features that attempt to resolve issues identified in previous literature in addition to needs defined from the survey responses. The developed software offers improvements over other databases in areas of transparency, data structure flexibility, and ability to facilitate user feedback. The software was implemented as a proof of concept, as a test-bed for attracting data contributions from LCA practitioners, and as a tool for interested users. The implementation allows users to add LCA data, to search through LCA data, and to use data from the software in separate independent tools.. The research contributes to the LCA field by addressing barriers to improving LCA data and access, and providing a platform on which LCA database tools and data can develop efficiently, collectively, and iteratively.

Over recent decades, environmental regulations on wastewater treatment plants (WWTP) have trended towards increasingly stringent nutrient removal requirements for the protection of local waterways. However, such regulations ignore the other environmental impacts that might accompany the apparent improvements to the WWTP. This PhD thesis used Life Cycle Assessment (LCA) to quantify these environmental trade-offs, and so better inform policy makers on the wider benefits and burdens associated with wastewater treatment. A particular focus was also given to the generation of methane and nitrous oxide in wastewater systems, since the quantification of greenhouse gas (GHG) emissions from WWTPs is presently a substantial area of uncertainty. Rapid changes to the GHG regulatory landscape mean that this level of uncertainty, now represents an unacceptable business risk for many water utilities. Specifically, there were three research objectives of this thesis: Research Objective No.1 – Environmental optimisation of wastewater treatment systems – For typical receiving environments, the optimum wastewater treatment system configuration is not necessarily at the limit of best practice for nutrient removal. The LCA approach to this research objective was divided into two stages. In stage I, a comprehensive desk-top life cycle inventory of ten different wastewater treatment scenarios was completed. The scenarios covered six process configurations and treatment standards ranging from raw sewage to advanced nutrient removal. It was shown that physical infrastructure, chemical usage and operational energy all increased with the level of nutrient removal. These trends represented a trade-off of negative environmental impacts against improved local receiving water quality. In stage II of the LCA, a quantitative life cycle impact assessment of the ten scenarios, referenced against Australian normalisation data, was completed. From a normalised perspective against Australian society, the contribution of WWTPs to headline issues such as global warming and energy consumption was found to be very small. The more prominent environmental impact categories were eutrophication due to nutrient discharge and toxicity issues, due to heavy metals in biosolids. There existed a broader environmental trade-off for nutrient removal, that could only be justified by society and regulators implicitly placing higher value on local water quality, than on other global environmental pressures. In light of this quantitative LCA, regulatory agencies should consider the broader environmental consequences of their policies such as the Queensland Water Quality Guidelines. It is suggested that the scope of WWTP licensing considerations should be widened from a singular focus on water quality objectives, to a more comprehensive LCA-based approach. Research Objective No. 2 – Quantification of nitrous oxide emissions from biological nutrient removal (BNR) wastewater treatment plants – Current GHG assessment methods for wastewater treatment plants are grossly inaccurate because of significant unaccounted N2O emissions. The research for objectives two and three was funded by the Water Services Association of Australia (WSAA), which is the peak body of the Australian urban water industry. Thus, whilst the earlier LCA results suggested that GHG emissions from WWTPs were insignificant from a national perspective, the industry is actually very engaged on this issue from an environmental responsibility and business risk perspective. This PhD study adopted a rigorous mass balance approach to determine N2O-N generation at seven full-scale WWTPs. The results varied considerably in the range 0.006 – 0.253 kgN2O-N generated per kgNdenitrified (average: 0.035 +/- 0.027). These results were generally larger than the current default value assumed in the National Greenhouse and Energy Reporting (Measurement) Technical Guidelines (i.e. 0.01 kg N2O-N.kgN-1denitrified). High N2O-N generation was shown to correspond with elevated bulk NO2--N concentrations in the bioreactor. The results also suggested that WWTPs designed for low effluent TN have lower and less variable N2O generation than plants that only achieve partial denitrification. Research Objective No.3 – Quantification of methane emissions from low-strength wastewater collection systems – Current default GHG assessment methods for sewerage systems are grossly inaccurate because of significant unaccounted CH4 emissions from rising mains. Presently, international GHG guidelines state that “wastewater in closed underground sewers is not believed to be a significant source of methane” (IPCC, 2006). However, the results of this PhD research demonstrated that methane generation in rising main sewers is substantial. It was shown that dissolved methane concentrations were dependent upon pipeline geometry and sewage residence time. Consequently, it was possible to develop a simple, yet robust, theoretical model that predicted methane generation from these two independent parameters. This model provides a practical means for water authorities globally to make an estimate of the currently unaccounted methane emissions from pressurised sewerage systems.

Over recent decades, environmental regulations on wastewater treatment plants (WWTP) have trended towards increasingly stringent nutrient removal requirements for the protection of local waterways. However, such regulations ignore the other environmental impacts that might accompany the apparent improvements to the WWTP. This PhD thesis used Life Cycle Assessment (LCA) to quantify these environmental trade-offs, and so better inform policy makers on the wider benefits and burdens associated with wastewater treatment. A particular focus was also given to the generation of methane and nitrous oxide in wastewater systems, since the quantification of greenhouse gas (GHG) emissions from WWTPs is presently a substantial area of uncertainty. Rapid changes to the GHG regulatory landscape mean that this level of uncertainty, now represents an unacceptable business risk for many water utilities. Specifically, there were three research objectives of this thesis: Research Objective No.1 – Environmental optimisation of wastewater treatment systems – For typical receiving environments, the optimum wastewater treatment system configuration is not necessarily at the limit of best practice for nutrient removal. The LCA approach to this research objective was divided into two stages. In stage I, a comprehensive desk-top life cycle inventory of ten different wastewater treatment scenarios was completed. The scenarios covered six process configurations and treatment standards ranging from raw sewage to advanced nutrient removal. It was shown that physical infrastructure, chemical usage and operational energy all increased with the level of nutrient removal. These trends represented a trade-off of negative environmental impacts against improved local receiving water quality. In stage II of the LCA, a quantitative life cycle impact assessment of the ten scenarios, referenced against Australian normalisation data, was completed. From a normalised perspective against Australian society, the contribution of WWTPs to headline issues such as global warming and energy consumption was found to be very small. The more prominent environmental impact categories were eutrophication due to nutrient discharge and toxicity issues, due to heavy metals in biosolids. There existed a broader environmental trade-off for nutrient removal, that could only be justified by society and regulators implicitly placing higher value on local water quality, than on other global environmental pressures. In light of this quantitative LCA, regulatory agencies should consider the broader environmental consequences of their policies such as the Queensland Water Quality Guidelines. It is suggested that the scope of WWTP licensing considerations should be widened from a singular focus on water quality objectives, to a more comprehensive LCA-based approach. Research Objective No. 2 – Quantification of nitrous oxide emissions from biological nutrient removal (BNR) wastewater treatment plants – Current GHG assessment methods for wastewater treatment plants are grossly inaccurate because of significant unaccounted N2O emissions. The research for objectives two and three was funded by the Water Services Association of Australia (WSAA), which is the peak body of the Australian urban water industry. Thus, whilst the earlier LCA results suggested that GHG emissions from WWTPs were insignificant from a national perspective, the industry is actually very engaged on this issue from an environmental responsibility and business risk perspective. This PhD study adopted a rigorous mass balance approach to determine N2O-N generation at seven full-scale WWTPs. The results varied considerably in the range 0.006 – 0.253 kgN2O-N generated per kgNdenitrified (average: 0.035 +/- 0.027). These results were generally larger than the current default value assumed in the National Greenhouse and Energy Reporting (Measurement) Technical Guidelines (i.e. 0.01 kg N2O-N.kgN-1denitrified). High N2O-N generation was shown to correspond with elevated bulk NO2--N concentrations in the bioreactor. The results also suggested that WWTPs designed for low effluent TN have lower and less variable N2O generation than plants that only achieve partial denitrification. Research Objective No.3 – Quantification of methane emissions from low-strength wastewater collection systems – Current default GHG assessment methods for sewerage systems are grossly inaccurate because of significant unaccounted CH4 emissions from rising mains. Presently, international GHG guidelines state that “wastewater in closed underground sewers is not believed to be a significant source of methane” (IPCC, 2006). However, the results of this PhD research demonstrated that methane generation in rising main sewers is substantial. It was shown that dissolved methane concentrations were dependent upon pipeline geometry and sewage residence time. Consequently, it was possible to develop a simple, yet robust, theoretical model that predicted methane generation from these two independent parameters. This model provides a practical means for water authorities globally to make an estimate of the currently unaccounted methane emissions from pressurised sewerage systems.

This study begins with a review of the concept of sustainability and sustainability indicators in the context of the pig and poultry industries in Santa Catarina State (SC), in Southern Brazil, and proposes an approach to the development of sustainability indicators for these industries. A review of the background and current situation of the pig and poultry industries in SC revealed that they are well organised into vertically integrated production systems and are regarded as being very competitive in world markets from technical and economic points of view. In 2002, SC produced 24% of total pork and 20% of total chicken production in Brazil in 2002, but this State has an area of only 95,000 km2, which amounts to just 1.1% of the country. SC also contributed 66% of pork exports and 54% of poultry exports from Brazil in 2002. So far the pig and poultry industries in SC have developed successfully, but recent changes towards more intensive production methods have resulted in much concern being expressed by the community, as the environmental impact of waste produced in the region has increased. The review of literature showed that in order to be sustainable, the pig and poultry industries in SC should acknowledge the concept of the “triple bottom line” and the principles of ecologically sustainable development. These include (i) biophysical or environmental sustainability, (ii) economic viability and (iii) social sustainability as criteria to guide industry development. The sustainability of the pig and poultry industries is influenced by local, regional, national and global factors which operate on several scales, and which in turn, indicate the need to use a multi-dimensional approach, combining environmental, economic, and social attributes. This study used a combination of qualitative and quantitative methods and was completed in four phases. In the first phase, an electronic survey of 205 stakeholders (complemented by 60 interviews with farmers) was undertaken to identify their views and perceptions of what sustainability meant to them. The survey was also designed to obtain stakeholders’ views on a suggested list of sustainability indicators. In Phase 2, the findings of the e-survey were discussed with panels of key industry stakeholders in 4 focus group discussions with of 47 participants to develop the list of indicators. In the third phase, a streamlined Life Cycle Assessment (LCA) study was conducted, to quantify the flows of materials, energy and of natural resource uses and to assess environmental impact. Finally, in Phase 4, stakeholder feedback was sought in 9 meetings to discuss and refine preliminary results and conclusions from the previous three phases of work. In the LCA the environmental burdens produced by typical intensive pig and poultry production systems were quantified and the contribution to each of nine selected environmental effects was estimated. The functional units (FU) were 1 tonne of live weight (LW) of pigs and 1 tonne of LW of chickens delivered to the gate of the abattoir. The boundaries of the systems analysed included the processes of producing fertilisers, feed products (maize and soybeans), energy, fuel, pesticides, production of rations, production of pigs and chickens and transportation required during all stages until the pigs and chickens are delivered to the abattoir. Data were collected from a variety of sources, including pig and poultry industry operators, research institutions, and agribusiness analysts from SC, as well as publicly available databases. Identified environmental hotspots in pig production were greenhouse gas emissions, acidification, and eutrophication, particularly from ration production and waste management. Environmental hotspots for poultry production reflect the high use of energy and pesticides, particularly associated with ration production from soybeans. The study concluded that although economic performance is competitive in world markets, most producers were operating outside the boundaries of sustainability because of inadequate waste management and excessive waste produced in a small geographical area, beyond the assimilation capacity of the local environment. This also causes other environmental effects (such as offensive odours, and increased numbers of blackflies, and houseflies), which were not quantified in the LCA study, but which were regarded as very important issues by stakeholders in the survey and focus group discussions. While comparing the overall environmental impact of producing 1 FU of pigs and poultry, this study concluded that under current production systems, pigs cause 68% greater impact than chickens. The key indicators proposed to assess the sustainability of the pig and poultry industries in SC were grouped into physical or environmental, economic, and social indicators. For physical and environmental indicators, monitoring the natural resource condition is the key indicator and requires measurement of attributes such as manure load per area of land and nutrient balance (P and K), soil condition, water use and water quality, agricultural plant species diversity, impact on native vegetation, and chemical residues in products. Among the economic indicators, long-term real net farm income and the industries’ overall competitiveness in national and international markets are key indicators. Attributes to measure these indicators are real net farm income, cost of production, farmer’s terms of trade, total factor productivity, and disposable income per farm household. Other farm level technical indicators which influence the economic outcome, such as feed conversion and productivity indices for pigs and poultry, also need to be monitored. For social indicators, the age structure and gender balance of the agricultural workforce, farmers’ managerial skills and level of training, as well as access to basic services, such as health, education, communications, and electricity in rural communities, are the key sustainability indicators. This study made four main contributions to knowledge: (a) the views and perceptions about sustainability among pig and poultry stakeholders were identified; (b) the environmental impacts of pig and poultry production were quantified and compared; (c) a set of key sustainability indicators for the pig and poultry industries was developed and validated; and (d) a framework for change towards sustainability and policy guidelines were suggested. The overall conclusion of the study is that, to be sustainable, the pig and poultry industries need to adjust their management practices, policies, and development strategies to incorporate the principles of ecologically sustainable development. Feeding strategies and methods of grain production have much influence on the key points of environmental impact, such as global warming, pesticides, and energy consumption. Waste management, however, has the greatest local impact, because of water and soil pollution and reduction in the quality of life due to offensive odours, blackflies, and houseflies. Sustainability indicators can thus assist to drive the industries to adopt improvements in the production systems to achieve better environmental performance. Although the findings of this study are confined to SC, the principles are generally applicable to other similar livestock industries in other places. The main justification for conducting this study rests on the increasing demands by the government, community and industry stakeholders for initiatives to reduce the impact of the pig and poultry production on the environment, while maintaining and enhancing its economic competitiveness in global markets and continuing to deliver important social benefits.

Coal-fired electricity production is the major emitter of CO2 and other greenhouse gases including NOx and SOx. Microalgae-based CO2 mitigation systems have been proposed to reduce the net CO2 emission from coal-fired power plants. This study focused on developing an optimum culture media and exploring the possibilities for recycling nutrients, which were added as commercial mineralized chemicals at the beginning of cultivation. In order to release the nutrients embedded in the cells so that they can be used as a nutrient source for new cells, Scenedesmus biomass was digested by anaerobic bacteria. Results showed that thermal pretreatment enhanced the methane production rate for the first 7 days of digestion. Three operational factors were tested: heating temperature, heating duration and NaOH dosage. The combination of 10 min heating with 3~6% NaOH at 50 °C gave the highest cell wall destruction for all samples except oven-dried algae. The anaerobic digestate, rich in mineralized nutrients including ammonium and phosphate, potassium and magnesium ions, was tested as a possible nutrient source for the algae cultivation. To cope with the high solid content of the digestates, the dosage of the digestates was reduced or the solid particles were removed prior to addition to the microalgae. Both approaches worked well in terms of providing nutrients with minimal effect on light penetration. Using digestates without any sterilization did not cause contamination or other deleterious effects on the Scenedesmus growth rate. Harvesting microalgae cells was critical to ensure a continuous and robust growth rate. The used media could be recycled at least four times without altering the algae growth. Nutrient replenishment was the key for a healthy culture when used media was incorporated. The combination of used media and digestates can sustain a normal algae growth. Life cycle assessment was conducted on the system including the photobioreactor, the anaerobic digester, the biomass settling and dewatering and used media and nutrient recycling. Considering methane as the energy source, the overall energy return of the system was 2.4. CO2 mitigation rate was about 39% under current mitigation system.

Understanding the energy input and emissions resulting from the development of biofuels is important to quantify the overall benefit of the biofuel. As part of the On-Farm Biomass Processing project, a life cycle assessment (LCA) was conducted on the process to harvest and transport agricultural crop residues ready for processing into biofuel. A Microsoft Excel model was developed that inventories the entire life cycle of the process, including incorporation of stochastic analysis within the model. The LCA results of the agricultural equipment manufacture are presented, along with the results of each step of the process, including fertilizer addition, single pass harvest, double pass harvest, and transport from the field to processing facility. Various methods of analyzing co-products are also presented for the single pass harvesting step, in which comparisons between market based, mass based and process-purpose based allocation methods are reviewed. The process-purpose based method of fuel consumption difference between combine operation in conventional harvest versus single pass harvest is determined to be the most realistic of the process. A detailed comparison of the energy and emission differences between single pass and double pass harvesting is given, along with the total LCA results of harvesting and transporting the biomass.