ABSTRACT
Inappropriate waste management is a considerable ecological risk, leading to detrimental effects on the soil, air, and water quality. It is imperative to address these concerns promptly to minimize the repercussions of solid waste on public health and the ecosystem. It is evident that the level of economic growth directly impacts waste generation. This study intends to use the life cycle assessment (LCA) technique to evaluate the environmental impacts of four alternative municipal solid waste (MSW) management scenarios in Peshawar City, Pakistan. The goal is to discover an option that is both sustainable and minimizes environmental damage. The study examined the system boundaries encompassing the collection and transportation of MSW, along with its processing and final disposal, employing composting, anaerobic digestion (AD), material recovery facilities (MRF), and landfill methods. Comprehensive field studies and an in-depth literature review provided the data regarding Peshawar's existing MSW management system and the proposed scenarios, all of which was inventoried in the OpenLCA 1.10.3 database. Following data collection, the CML-IA technique was employed to analyze the data, measuring the environmental footprint in terms of climate change potential, human toxicity, acidification potential, photochemical oxidation, and eutrophication. A sensitivity analysis was also performed to identify the influence of varying recycling rates on the environmental strain correlated with the proposed scenarios. The analysis results indicated that scenario S2, which combined composting, landfilling, and MRF, exhibited the least environmental impact compared to the other considered scenarios. Furthermore, the sensitivity analysis reflected an inverse correlation between alterations in the recycling rate and the total environmental impact. To counter the environmental problems arising from waste generation, it is essential to incorporate principles of the circular economy into the MSW management approach.
ABSTRACT
The iron-based biomass-supported catalyst has been used for Fischer-Tropsch synthesis (FTS). However, there is no study regarding the life cycle assessment (LCA) of biomass-supported iron catalysts published in the literature. This study discusses a biomass-supported iron catalyst's LCA for the conversion of syngas into a liquid fuel product. The waste biomass is one of the source of activated carbon (AC), and it has been used as a support for the catalyst. The FTS reactions are carried out in the fixed-bed reactor at low or high temperatures. The use of promoters in the preparation of catalysts usually enhances C5+ production. In this study, the collection of precise data from on-site laboratory conditions is of utmost importance to ensure the credibility and validity of the study's outcomes. The environmental impact assessment modeling was carried out using the OpenLCA 1.10.3 software. The LCA results reveals that the synthesis process of iron-based biomass supported catalyst yields a total impact score in terms of global warming potential (GWP) of 1.235E + 01 kg CO2 equivalent. Within this process, the AC stage contributes 52% to the overall GWP, while the preparation stage for the catalyst precursor contributes 48%. The comprehensive evaluation of the iron-based biomass supported catalyst's impact score in terms of human toxicity reveals a total score of 1.98E-02 kg 1,4-dichlorobenzene (1,4-DB) equivalent.
ABSTRACT
In adsorptive water treatment applications, the exploration of waste-derived activated carbon (AC) has gained substantial attention in scientific research. The use of waste materials as precursors for AC has gained attention due to its economic viability and potential to reduce the consumption of non-renewable resources. However, there is a lack of comprehensive literature regarding the costs and environmental impacts associated with the waste-based AC production and application. As sustainability practices gain importance, there has been an increase in research dedicated to estimating costs and conducting life cycle assessment (LCA) of AC production from waste sources. However, there is a need for thorough literature reviews that cover various methodologies and conclusions. The primary objective of this study is to provide a comprehensive overview and analysis of the economic and environmental factors related to the use of waste-derived AC in water treatment. LCA studies indicate that utilizing waste materials for AC production can lead to significant resource and energy savings compared to conventional methods relying on fossil resources. The cost of AC is influenced by factors such as precursor material cost, energy requirements during production (optimizable on an industrial scale), and properties of the resulting material. Additionally, the review emphasizes the significance of waste-based AC regeneration for sustainable viability. Evaluating the environmental and economic costs is crucial to support sustainability claims and avoid unsupported assertions. Overall, this study contributes to understanding the potential of waste-derived AC in water treatment and highlights the need for further research in this area.
ABSTRACT
Gasification and pyrolysis are thermal processes for converting carbonaceous substances into tar, ash, coke, char, and gas. Pyrolysis produces products such as char, tar, and gas, while gasification transforms carbon-containing products (e.g., the products from pyrolysis) into a primarily gaseous product. The composition of the products and their relative quantities are highly dependent on the configuration of the overall process and on the input fuel. Although in gasification, pyrolysis processes also occur in many cases (yet prior to the gasification processes), gasification is a common description for the overall technology. Pyrolysis, on the other hand, can be used without going through the gasification process. The current study evaluates the most common waste plastics valorization routes for producing gaseous and liquid products, as well as the key process specifications that affected the end final products. The reactor type, temperatures, residence time, pressure, the fluidizing gas type, the flow rate, and catalysts were all investigated in this study. Pyrolysis and waste gasification, on the other hand, are expected to become more common in the future. One explanation for this is that public opinion on the incineration of waste in some countries is a main impediment to the development of new incineration capacity. However, an exceptional capability of gasification and pyrolysis over incineration to conserve waste chemical energy is also essential.
