RESUMEN
This study aims to identify the role of design and operational parameters in energy costs for a wastewater treatment plant in a meat processing industry regarding water-energy nexus. In the study, the energy cost index has been calculated using a derived numerical approach. This study recommends a new comprehensive methodology for energy cost estimation for an industrial wastewater treatment plant. The model is developed based on organic load, amount of wastewater, and energy consumption required to treat wastewater. Particularly, the impact of design and operational organic load parameters on energy costs has been investigated in this study. Biological oxygen demand (BOD) and chemical oxygen demand (COD) have been regarded as organic load indicators. The results show that the energy cost index of operational organic load is higher than that of the design for two parameters. Energy costs of COD removal are higher than BOD removal. The costs of COD removal are 726.6 and 65,520 /m3 wastewater for design and operational conditions, respectively, whereas the energy costs related to BOD removal are 90.9 and 7224 /m3 wastewater for design and operational conditions, respectively. Operational COD removal leads to maximum energy costs for the plant. The lowest energy cost is related to BOD removal of design conditions. In terms of water-energy nexus, wastewater reuse could be considered to reduce energy costs. The possibility of wastewater reuse as boiler feed water has been reported as 50.38%. According to the simulated results, energy costs could be minimized at approximately 49% if wastewater reuse were applied in the plant.
Asunto(s)
Eliminación de Residuos Líquidos , Purificación del Agua , Análisis de la Demanda Biológica de Oxígeno , Residuos Industriales/análisis , Carne , Aguas Residuales , AguaRESUMEN
Water and energy are closely interlinked during their production and consumption processes. The limited and temporary distribution of energy and water resources poses a significant environmental challenge. Industrial wastewater treatment plants are essential elements of water production and also significant energy consumers. This study proposes a methodology for energy management of a wastewater treatment plant. Specifically, it examines the impact of optimum operating conditions on energy costs for a dairy wastewater treatment plant using a dissolved air flotation process. Monte Carlo simulation was used to optimize the parameters and to determine the reuse potential of dairy effluent. Firstly, the optimum operating conditions were determined. The results revealed a maximum fat, oil, and grease removal efficiency of 97% and a chemical oxygen demand removal efficiency of 70%. The optimum conditions were pH of 8, a saturation pressure of 5 bars, and a recirculation ratio of 33%. The optimum concentrations of coagulant and flocculant that contain polyaluminum chloride and cationic polymer were 20 mg/L and 25 mg/L, respectively. The results of the simulation study gave a recirculation ratio of 26.31%, a polyaluminum chloride concentration of 42.5 mg/L, a cationic polymer concentration of 36.31 mg/L, and a saturation pressure of 4.61 bars. Finally, energy cost assessment was performed using a newly developed model which showed that the energy cost indicator of the existing process was lower than optimum operating conditions. The reuse potential of dairy effluent as cooling water was found to be 52%.