Comparative life cycle assessment of system solution scenarios for residual municipal solid waste management in NSW, Australia.

Life cycle assessment (LCA) is a promising tool to evaluate the environmental impacts of different technologies for sustainable waste management. This study employs LCA to assess environmental impacts of alternative scenarios for residual municipal solid waste (MSW) management in New South Wales (NSW) based on current conditions and policies. Six different scenarios including a baseline scenario (landfilling) were applied for NSW waste management for energy production and their impacts on environment. The initial results showed that the scenario 3 that employed anaerobic digestion for food waste, incineration for combustible waste and plastic waste, and landfilling for non-combustible waste produced electricity of 625 kWh/t, which was maximum compared to the other scenarios. LCA results further suggested that among all scenarios, scenario 5 (similar to scenario 3 except combustible waste was treated through gasification and plastic waste was recycled) has the lowest level of environmental burdens in global warming, freshwater and marine ecotoxicity, and human non-carcinogenic toxicity. The sensitivity analysis for energy conversion rates (23-30%) for incineration and plastic recycling rate (66-91.3%) for MSW was further conducted and the results showed that energy conversion rate of 30% makes scenario 3 more valuable for electricity generation and less impactful for ecosystems damage category compared to scenario 5. On the other hand, plastic recycling rate of 91.3% has the lowest environmental burdens and by decreasing recycling rate to 66% the environmental impacts increase; however, it was noticed that reduction in recycling rate does not make any change in the order of scenarios. Overall, the study suggests that each waste type in NSW should be treated with a specific technology to achieve the highest resource recovery and lowest environmental impacts where energy conversion and plastic recycling rates have significant impacts.

Interrelationship of microplastic pollution in sediments and oysters in a seaport environment of the eastern coast of Australia.

Since the middle of the twentieth century, microplastics have emerged as a pollutant of concern. Sea ports are recipients of large amount of discharges through ballast water, ship traffic and other commercial activities, which may additionally add to the overall marine microplastic pollution. The aim of this study was to determine the interrelationship of microplastic pollution in the sediments and oysters at six major seaports (Port Jackson, Botany, Kembla, Newcastle, Yamba and Eden) of New South Wales (NSW). The results revealed the significant abundance of microplastic particles both in sediments and oysters in all the studied seaports which were estimated to be around 83-350 particles/kg dry weight in the sediments and 0.15-0.83 particles/g wet weight in the oysters. Although, the abundance of microplastics showed similar pattern in the sediments and oysters of the studied seaports, oysters had higher number of microplastics than sediments in all sea ports. Moreover, the results showed that the shapes, size and colours in the oysters did not necessarily match the main components in the sediments, although the polymer types matched well between each other. Black fibres between 0.1mm-0.5mm in size were the most abundant microplastics in oysters, whereas white spherules between 0.5mm-1mm in size were dominant in the sediments of NSW seaports. Moreover, the analysis of variance between microplastic abundance in sediment and oysters showed a non-significant positive linear relationship. Fourier Transform Infrared analysis further indicated that both sediments and oysters contained microplastics with two main polymers, polyethylene terephthalate and nylon, which suggests that the abundance of microplastics in the study ports was highly influenced by the port activities, mainly the intensive commercial fishing and fish processing activities along with intensive anthropogenic and industrial activities inside and surroundings the port environments.

Bio-oil upgrading with catalytic pyrolysis of biomass using Copper/zeolite-Nickel/zeolite and Copper-Nickel/zeolite catalysts.

The bio-oil obtained from a general pyrolysis process contains a higher concentration of oxygenated compounds and the resultant physical and chemical properties make it an unsuitable drop-in fuel. The oxygenated compounds in the bio-oil can be converted into hydrocarbons or less oxygenated compounds with the application of catalysts. This study demonstrated the bio-oil upgrading with the application of catalysts, comparing the catalytic effect of combined mono-metallic catalysts (Cu/zeolite and Ni/zeolite) and sole bi-metallic catalyst (CuNi/zeolite) on the composition of bio-oil and pyrolytic gases. The results demonstrated that in comparison to the combined mono-metallic catalysts, the sole bi-metallic catalyst showed better deoxygenation for all the oxygenated compounds and favoured the production of aliphatic hydrocarbons, whereas the combination of mono-metallic catalysts generated higher proportion of aromatic hydrocarbons in the bio-oil. In both cases, the catalysts equally favoured decarboxylation and decarbonylation reactions, as CO2/CO of approximately 1 was obtained during the pyrolysis process.