Enda Crossin

Anaerobic co-digestion of municipal food waste and sewage sludge: A comparative life cycle assessment in the context of a waste service provision

This study used life cycle assessment to evaluate the environmental impact of anaerobic co-digestion (AcoD) and compared it against the current waste management system in two case study areas. Results indicated AcoD to have less environmental impact for all categories modelled excluding human toxicity, despite the need to collect and pre-treat food waste separately. Uncertainty modelling confirmed that AcoD has a 100% likelihood of a smaller global warming potential, and for acidification, eutrophication and fossil fuel depletion AcoD carried a greater than 85% confidence of inducing a lesser impact than the current waste service.

Energy and time modelling of kerbside waste collection: Changes incurred when adding source separated food waste

The collection of source separated kerbside municipal FW (SSFW) is being incentivised in Australia, however such a collection is likely to increase the fuel and time a collection truck fleet requires. Therefore, waste managers need to determine whether the incentives outweigh the cost. With literature scarcely describing the magnitude of increase, and local parameters playing a crucial role in accurately modelling kerbside collection; this paper develops a new general mathematical model that predicts the energy and time requirements of a collection regime whilst incorporating the unique variables of different jurisdictions. The model, Municipal solid waste collect (MSW-Collect), is validated and shown to be more accurate at predicting fuel consumption and trucks required than other common collection models. When predicting changes incurred for five different SSFW collection scenarios, results show that SSFW scenarios require an increase in fuel ranging from 1.38% to 57.59%. There is also a need for additional trucks across most SSFW scenarios tested. All SSFW scenarios are ranked and analysed in regards to fuel consumption; sensitivity analysis is conducted to test key assumptions.

Life cycle assessment to compare the environmental impact of seven contemporary food waste management systems

Municipal food waste (FW) represents 35-45% of household residual waste in Australia, with the nation generating 1.6Tg annually. It is estimated that 91% of this FW ends up in landfill. This study used life cycle assessment to determine and compare the environmental impact of seven contemporary FW management systems for two real-life jurisdictions; incorporating the complete waste service and expanding the system to include inert and garden waste. Although, no system exhibited a best ranking across all impact categories, FW digestion based systems were all revealed to have a lower global warming potential than composting and landfilling systems. Mechanical biological treatment, anaerobic co-digestion, and home composting all demonstrated the lowest environmental impacts for two or more of the environmental impact categories assessed. The assessment included market and technological specific variables and uncertainties providing a framework for robust decision making at a municipality level.

A greenhouse gas assessment of a stadium in Australia

A greenhouse gas (GHG) life cycle assessment (LCA) was performed on a stadium used for sporting events in a subtropical region in Australia. Inventories for the construction and operation of a stadium are presented and the GHG emissions from construction, operations and end-of-life waste management are assessed against the attendance of one person at one event. The inclusion of additional economic activities, patron travel, LCA methodology, attendance and stadium life-time assumptions are likely to affect the overall magnitude of the GHG emissions of one persons attendance. The assessment shows that the stadium operation accounted for 72.5% of GHG emissions, with the operation of baseload heating, ventilation and cooling, lighting and refrigeration systems dominating. The best opportunity to reduce GHG emissions is to reduce the need for the continual operation of these systems. Construction impacts account for 24.7% of impacts, while replacement materials, end-of-life management of materials are relatively insignificant, contributing to less than 3% of life cycle GHG emissions.

Assessing environmental impact of textile supply chain using life cycle assessment methodology

Abstract The environmental impact of textile supply chain of selected cotton, wool and polyester apparels consumed in Australia was accessed in this study using life cycle assessment methodology. The environmental impact category, climate change was used for this assessment. Climate change is related to the emissions of greenhouse gases to the atmosphere and the reference unit of climate change impact category is kg CO2 equivalent. The environmental impact of these apparels was then scaled up based on their total consumption in Australia in 2015. The results highlight the differences in environmental impact between the three apparels. This study demonstrates that the main contributor to climate change is the consumer use stage for cotton and polyester apparel whereas wool apparel production process contributes more impact than consumer use stage. Energy use is the main factor of environmental impact. Sensitivity analysis was carried out based on the different parameters used to develop baseline model, such as change of transport from airfreight to sea freight; change of transport distance, change of consumer laundering behaviour. Around 10% CO2 equivalent emission can be reduced from base case by reducing washing machine energy up to 40%. A high efficient washing machine and full load machine wash can save energy and reduce carbon emission.