Browsing by Author "Sala-Garrido, Ramon"

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    Assessing changes in eco-productivity of wastewater treatment plants: The role of costs, pollutant removal efficiency, and greenhouse gas emissions
    (2018) Gemar, German; Gomez, Trinidad; Molinos Senante, María; Caballero, Rafael; Sala-Garrido, Ramon; CEDEUS (Chile)
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    Assessing eco-efficiency of wastewater treatment plants: A cross-evaluation strategy
    (2023) Sala-Garrido, Ramon; Maziotis, Alexandros; Mocholi-Arce, Manuel; Molinos-Senante, Maria
    Evaluating the eco-efficiency of wastewater treatment plants (WWTPs) is crucial for enhancing environmental and economic performance in the water utility sector. Previous studies in this area estimated WWTP eco-efficiency through self-evaluation, which might have led to overestimation and biased policy recommenda-tions. To address these issues, this study applies a cross-evaluation strategy, combining self-evaluation and peer -evaluation, to assess the eco-efficiency of WWTPs. The empirical application focuses on a sample of Spanish WWTPs, yielding the following key findings. Average eco-efficiency scores were 0.353 and 0.230, for self -evaluation and global peer-evaluation approaches, respectively, confirming the overestimation of eco-efficiency scores based on self-evaluation. If WWTPs were eco-efficient, they could potentially reduce green-house gas (GHG) emissions by up to 0.39 kg CO2eq/year. The application of reliable methods, such as peer -evaluation, for eco-efficiency assessment of WWTPs provides water regulators with a comprehensive under-standing of the environmental and economic performance of WWTPs. This knowledge guides decision-making, policy development, and resource allocation, facilitating sustainable and efficient wastewater management practices.
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    Eco-Efficiency of the English and Welsh Water Companies: A Cross Performance Assessment
    (2021) Sala-Garrido, Ramon; Mocholi-Arce, Manuel; Molinos-Senante, Maria; Smyrnakis, Michail; Maziotis, Alexandros
    Analyzing costs and greenhouse gas (GHG) emissions could be of great importance for the water utilities to supply water services in a healthy and sustainable manner. In this study, we measured the eco-efficiency of several water utilities in England and Wales by incorporating GHG as an undesirable output. For the first time, we evaluated the eco-efficiency of the water production process using robust cross-efficiency data envelopment analysis (DEA) techniques. The further use of clustering and regression techniques allowed us to better understand the drivers of eco-efficiency. The results showed that the mean eco-efficiency of the water sector was 0.748, which indicates that costs and GHG emissions could be reduced by 25.2% to generate the same level of output. Large water companies with high energy costs and levels of GHG emissions belonged to the less eco-efficient group. Environmental factors related to density, topography, and treatment complexity further impacted eco-efficiency. Finally, we linked our results to the regulatory cycle and discuss some policy implications.
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    Estimating the impact of carbon inefficiency and overuse of energy on the economics of water companies: A case study for England and Wales
    (2024) Maziotis, Alexandros; Sala-Garrido, Ramon; Mocholi-Arce, Manuel; Molinos-Senante, Maria
    In the face of climate change, it becomes crucial to motivate action and policies within water companies towards achieving carbon neutrality. Estimating the economic consequences of inaction can be a compelling catalyst for change. In this study, the carbon inefficiency and overuse of energy among a selection of English and Welsh water companies were assessed, along with their impact on the operational costs of producing and delivering drinking water over the period from 2010 to 2019. In doing so, a stochastic frontier analysis primal system was employed. The findings revealed that, on average, water companies exhibited a carbon inefficiency of 0.699. The overuse of energy relative to other inputs was estimated to be 71.4%. Consequently, water companies incurred a production cost increase of 0.089 pound/m3. This research demonstrates that transitioning towards a low-carbon urban water cycle is not merely an environmental beneficial endeavor; it also involves significant economic advantages.
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    How much does it cost to collect recyclable and residual waste in medium-income countries? A case study in the Chilean waste sector
    (2022) Molinos-Senante, Maria; Maziotis, Alexandros; Sala-Garrido, Ramon; Mocholi-Arce, Manuel
    Improper municipal solid waste (MSW) management leads to contamination of water, soil and air with negative impacts on human health. Moreover, not dealing with residual waste has huge implications for meeting circular economy targets. Understanding how much it costs could lead to a better quality of service and boost environmental sustainability. This study estimates an input distance function using econometric techniques to measure the technical efficiency of the MSW sector in Chile. This approach further allows us to estimate the shadow price of residual waste in terms of total costs. The results indicated that the average technical efficiency of the waste sector was 0.592. This means that the potential savings in costs and residual waste among municipalities could be at the level of 40.8%. Large divergences among municipalities were found since efficiency scores ranged between 0.029 and 0.863. It is found that for 53% of the municipalities evaluated, efficiency scores varied between 0.61 and 0.80. On average, the cost of reducing residual waste was 81.10 US $ per kilogram. This means that on average the cost of preventing one more kilogram of residual waste not being collected and recycled was 81.10 US $. It was also found that on average as population density increased, the shadow price of residual waste increased as well.Implications: The study provides a methodology that allows the policy makers to estimate the efficiency of the solid waste sector where limited available statistical data usually exists in developing and medium-income countries. They have the opportunity to understand what drives costs and identify the best and worst performers. This information is essential to develop local initiatives to enhance waste recycling and therefore, achieving the targets established at national level. Managers can also see if there are other operating factors that could influence performance such as population density. The proposed methodology allows integrating other exogenous variables that might be interesting to policy makers. For instance, a tourism index could be included in the assessment to evaluate whether tourism impacts on the efficiency of municipalities in the provision of municipal solid waste services and therefore, to analyze the implementation of an eco-tax for tourists.