Integrating data reconciliation into material flow cost accounting: The case of a petrochemical wastewater treatment plant

Material flow cost accounting analyzes input/output relations of material flows in the production process based on mass balance principles. However, the measured data of a process contains errors representing a mass imbalance in the system such as that of a wastewater treatment plant. Therefore, measured data should be verified before establishing mass balance and, subsequently, material flow cost accounting. Hence, in this work, a novel practical stepwise methodology using data reconciliation technique is introduced to improve the accuracy and certainty of measurements before material flow cost accounting. A full-scale petrochemical wastewater treatment plant was selected to establish this methodology. The presented results of this case study show an error of -3.22% (-35244 t/year) between total input and output streams of wastewater treatment plant demonstrating mass imbalance in the system. However, the overall mass balance could be closed by simultaneously solving the incidence matrix (system of balances). The results revealed that by including data reconciliation into material flow cost accounting, an accurate mass balance can be performed, which is a key element in material flow cost accounting calculations. The comparison results showed a relatively significant difference between material flow cost accounting for reconciled and measured data (unreconciled). The developed approach provides a reliable set of data for implementing material flow cost accounting in the system. Therefore, using this novel stepwise approach will help decision-makers to enhance both financial and environmental performances more confidently and to define appropriate improvement plans. (C) 2019 Elsevier Ltd. All rights reserved.