Joint Environmental and Economical Analysis of Wastewater Treatment Plants Control Strategies: A Benchmark Scenario Analysis

Abstract

Abstract:In this paper, a joint environmental and economic analysis of different Wastewater Treatment Plant (WWTP) control strategies is carried out. The assessment is based on the application of the Life Cycle Assessment (LCA) as a method to evaluate the environmental impact and the Benchmark Simulation Model No. 1 (BSM1). The BSM1 is taken as the benchmark scenario used to implement the control strategies. The Effluent Quality Index (EQI) and the Overall Cost Index (OCI) are two indicators provided by BSM1 and used to evaluate the plant's performance from the effluent quality and the economic points of view, respectively. This work conducts a combined analysis and assessment of ten different control strategies defined to operate a wastewater treatment plant. This analysis includes the usual economic and performance indexes provided by BSM1 joined with the LCA analysis that determines the environmental impact linked to each one of the considered control strategies. It is shown how to get an overall evaluation of the environmental effects by using a normalized graphical representation that can be easily used to compare control strategies from the environmental impact point of view. The use of only the BSM1 indexes provides an assessment that leads to a clustering of control strategies according to the cost/quality tradeoff they show. Therefore, regarding the cost/quality tradeoff, all strategies in the same group are almost equal and do not provide an indication on how to proceed in order to select the appropriate one. It is therefore shown how the fact of adding a new, complementary, evaluation (LCA based) allows either to reinforce a decision that could be taken solely on the basis of the EQI/OCI tradeoff or to select one control strategy among the others.

Wastewater Treatment Plant Operation: Simple Control Schemes with a Holistic Perspective

“…Removing pollutants from wastewater entails consumption of energy, use of chemicals, and treatment of sludge in excess, which are operating expenses that cannot be compensated with economic profitable products. In addition, the operation of a WWTP involves environmental impacts such as direct emissions of greenhouse gases (GHG) from biological processes, indirect emissions of GHG from energy use (electricity and heating), and sludge disposed to land and toxicity of chemicals [1,2]. Such environmental costs affect process sustainability, which plays an important role in process management in the actual context.…”

“…A number of performance indicators have been defined to address the cost-effective operation and sustainability of WWTPs [4,[6][7][8]. The impact of greenhouse (GHG) emissions associated with wastewater treatment has been introduced as an important factor in the evaluation of plant performance in [3,9], and Life Cycle Assessment (LCA) has been used to evaluate sustainable operation of WWTPs in [1,2,10] and integrated water systems in [8,11], providing a wider perspective for the evaluation of economic performance and sustainability in the operation of these processes. The available quantitative indicators of performance provide an instrument to carry out a comprehensive analysis of the impact of operating conditions on the efficiency of the plant.…”

“…Few works are found in the literature ( [5,19]) dealing with the implementation of control strategies to improve the overall performance of WWTPs introducing plantwide considerations. Moreover, few works [1,2] evaluate the effect of the control system performance considering its impact on the whole plant behavior in terms of economic and environmental costs. In this work, a control approach is proposed that uses a measure of global efficiency of the plant as the controlled variable with the aim of introducing some sense of optimization in the control actions addressing effluent quality goals and energy consumption in the whole plant.…”

Control en Estaciones Depuradoras de Aguas Residuales: Estado actual y perspectivas

“…Generalmente, la metodología LCA sirve como complemento dentro de un escenario de decisión multicriterio. Así por ejemplo, en Meneses et al (2015) y Meneses et al (2016) se aplica LCA para analizar los impactos generados por un conjunto de estrategias de operación de EDAR centradas en el benchmark BSM1. Se plantea LCA como una herramienta de ayuda a la evaluación de estrategias de operación mostrando como puede complementar a loś ındices de calidad y coste establecidos en las plataformas BSM.…”

Computerized control strategy to prevent wastewater plants pollution

“…Combined sewer systems are designed to carry both raw sewage and storm water runoff to sewage treatment plants. New control methods are implemented in wastewater treatment plants [1][2] [3], and effects of environmental factors have been also studied [4]. But even with the proposed methodologies, during heavy rainstorms these systems can become hydraulically overloaded and discharge a mixture of raw sewage and polluted runoff from streets into local waterways.…”