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Material flow analysis is used to quantify the material turnover of a defined system, relying on data about flows and stocks from different sources with varying quality. In this study, the belief that the available data are representative for the value of interest is expressed via fuzzy sets, specifying the possible range of values of the data. A possibilistic framework for data reconciliation in MFA was developed and applied to a case study on wood flows in Austria. The framework consists of a data characterisation and a reconciliation step. Membership functions are defined based on the collected data and data quality assessment. Possible ranges and consistency levels (quantifying the agreement between input data and balance constraints) are determined. The framework allows problematic data and model weaknesses to be identified and can be used to illustrate the trade-off between confidence in the data and the consistency levels of resulting material flows.

Material flow analysis is used to quantify the material turnover of a defined system, relying on data about flows and stocks from different sources with varying quality. In this study, the belief that the available data are representative for the value of interest is expressed via fuzzy sets, specifying the possible range of values of the data. A possibilistic framework for data reconciliation in MFA was developed and applied to a case study on wood flows in Austria. The framework consists of a data characterisation and a reconciliation step. Membership functions are defined based on the collected data and data quality assessment. Possible ranges and consistency levels (quantifying the agreement between input data and balance constraints) are determined. The framework allows problematic data and model weaknesses to be identified and can be used to illustrate the trade-off between confidence in the data and the consistency levels of resulting material flows.

Several studies evaluated the feasibility of using residues to compose asphalt mixtures. However, the demand for treatments are often neglected in determining the environmental impacts. This study ...

Several studies evaluated the feasibility of using residues to compose asphalt mixtures. However, the demand for treatments are often neglected in determining the environmental impacts. This study ...

Abstract A mixing strategy capable of handling a suitable agitation within digester tanks is a necessity in order to assure continuous contact of substrates and degraders inside bioreactors. As mixing is an energy demanding process, the energy needed for a proper mixing contributes to overall efficiency of digesters. In the current study, the aim is to assess the incorporation of biogas bubble creation into the mixing of anaerobic digesters of wastewater treatment plants (WWTP) tanks with and without an external vertical mixer, in order to analyze the possibility of considering bubble creation as an imperative factor in the mixing scenario. Computational fluid dynamics (CFD) prepares the opportunity to simulate the creation biogas bubbles within a stirred tank of anaerobic digester, in a combination of an Eulerian and Lagrangian platform. The amount of dead volume, average velocity, velocity gradient and bubble particle trajectories are analyzed and discussed. Our key findings are as follows: biogas bubble creation contributes to the reduction of dead volume inside the digester tank, once there is no external rotating mixing, or once the amount of mixer rotation speed is low. However, either in low or in high mixer rotation speed the biogas bubble creation does not have a considerable effect of velocity gradient.