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Maziotis A, Molinos-Senante M. A COMPRENHESIVE ECO-EFFICIENCY ANALYSIS OF WASTEWATER TREATMENT PLANTS: ESTIMATION OF OPTIMAL OPERATIONAL COSTS AND GREENHOUSE GAS EMISSIONS. WATER RESEARCH 2023; 243:120354. [PMID: 37517147 DOI: 10.1016/j.watres.2023.120354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/11/2023] [Accepted: 07/13/2023] [Indexed: 08/01/2023]
Abstract
The transition to a neutral carbon and sustainable urban water cycle requires improving eco-efficiency in wastewater treatment processes. To support decision-making based on eco-efficiency evaluations, reliable estimations are fundamental. In this study, the eco-efficiency of a sample of 109 WWTPs was evaluated using efficiency analysis tree method. It combines machine learning and linear programming techniques and therefore, overcomes overfitting limitations of non-parametric methods used by past research on this topic. Results from the case study revealed that optimal costs and greenhouse gas emissions depend on the quantity of organic matter and suspended solids removed from wastewater. The estimated average eco-efficiency is 0.373 which involves that the assessed WWTPs could save 0.32 €/m3 and 0.11 kg of CO2 equivalent/m3. Moreover, only 4 out of 109 WWTPs are identified as eco-efficient which implies that the majority of the evaluated facilities can achieve substantial savings in operational costs and greenhouse gas emissions.
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Affiliation(s)
- Alexandros Maziotis
- Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna, Santiago, Chile
| | - Maria Molinos-Senante
- Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna, Santiago, Chile; Instituto de Procesos Sostenibles, Universidad de Valladolid, C/ Mergelina 4, Valladolid, Spain.
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Maziotis A, Sala-Garrido R, Mocholi-Arce M, Molinos-Senante M. A comprehensive assessment of energy efficiency of wastewater treatment plants: An efficiency analysis tree approach. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 885:163539. [PMID: 37146822 DOI: 10.1016/j.scitotenv.2023.163539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/12/2023] [Accepted: 04/12/2023] [Indexed: 05/07/2023]
Abstract
Wastewater treatment plants (WWTPs) are energy intensive facilities. Controlling energy use in WWTPs could bring substantial benefits to people and environment. Understanding how energy efficient the wastewater treatment process is and what drives efficiency would allow treating wastewater in a more sustainable way. In this study, we employed the efficiency analysis trees approach, that combines machine learning and linear programming techniques, to estimate energy efficiency of wastewater treatment process. The findings indicated that considerable energy inefficiency among WWTPs in Chile existed. The mean energy efficiency was 0.287 suggesting that energy use should cut reduce by 71.3 % to treat the same volume of wastewater. This was equivalent to a reduction in energy use by 0.40 kWh/m3 on average. Moreover, only 4 out of 203 assessed WWTPs (1.97 %) were identified as energy efficient. It was also found that the age of treatment plant and type of secondary technology played an important role in explaining energy efficiency variations among WWTPs.
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Affiliation(s)
- Alexandros Maziotis
- Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna, 4860 Santiago, Chile
| | - Ramon Sala-Garrido
- Department of Mathematics for Economics, University of Valencia, Avd. Tarongers S/N, Valencia, Spain
| | - Manuel Mocholi-Arce
- Department of Mathematics for Economics, University of Valencia, Avd. Tarongers S/N, Valencia, Spain
| | - Maria Molinos-Senante
- Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna, 4860 Santiago, Chile; Institute of Sustainable Processes, University of Valladolid, C/ Dr. Mergelina, S/N, Valladolid, Spain; Centro de Desarrollo Urbano Sustentable ANID/FONDAP/15110020, Av. Vicuña Mackenna, 4860 Santiago, Chile.
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Feng Z, Xu C, Zuo Y, Luo X, Wang L, Chen H, Xie X, Yan D, Liang T. Analysis of water quality indexes and their relationships with vegetation using self-organizing map and geographically and temporally weighted regression. ENVIRONMENTAL RESEARCH 2023; 216:114587. [PMID: 36270529 DOI: 10.1016/j.envres.2022.114587] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/29/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
Natural vegetation has been proved to promote water purification in previous studies, while the relevant laws has not been excavated systematically. This research explored the relationships between vegetation cover and water quality indexes in Liaohe River Basin in China combined with self-organizing map (SOM) and geographically and temporally weighted regression (GTWR) innovatively and systematically based on the distributing heterogeneity of water quality conditions. Results showed that the central and northeast regions of the study area had serious organic and nutrient pollution, which needed targeted treatment. And SOM verified that high vegetation coverage with retention potential of organic and inorganic pollutants as well as nutrients improved water quality to some degree, while the excessive discharges of pollutants still had serious threats to nearby water environment despite the purification function of vegetation. GTWR indicated that the waterside vegetation was beneficial for dissolved oxygen increasing and contributed to the decreasing of organic pollutants and inorganic pollutants with reducibility. Natural vegetation also obsorbed nutrients like TN and TP to some degree. However, the retential potential of nitrogen and organic pollutants became not obvious when there were heavy pollution, which demonstrated that pollution sources should be controlled despite the purification function of vegetation. This study implied that natural vegetation purified water quality to some degree, while this function could not be revealed when there was too heavy pollution. These findings underscore that the pollutant discharge should be controlled though the natural vegetation in ecosystem promoted the purification of water bodies.
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Affiliation(s)
- Zhaohui Feng
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chengjian Xu
- Changjiang Institute of Survey, Planning, Design and Research Co., Ltd, Wuhan 430010, China; Hubei Provincial Engineering Research Center for Comprehensive Water Environment Treatment in the Yangtze River Basin, Wuhan, 430010, China
| | - Yiping Zuo
- Foreign Environmental Cooperation Center, Ministry of Ecology and Environment, Beijing 100035, China
| | - Xi Luo
- Changjiang Institute of Survey, Planning, Design and Research Co., Ltd, Wuhan 430010, China; Hubei Key Laboratory of Basin Water Security, Wuhan 430010, China
| | - Lingqing Wang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Hao Chen
- Changjiang Institute of Survey, Planning, Design and Research Co., Ltd, Wuhan 430010, China; Key Laboratory of Changjiang Regulation and Protection of Ministry of Water Resources, Beijing 100053, China
| | - Xiaojing Xie
- Changjiang Institute of Survey, Planning, Design and Research Co., Ltd, Wuhan 430010, China; Hubei Provincial Engineering Research Center for Comprehensive Water Environment Treatment in the Yangtze River Basin, Wuhan, 430010, China
| | - Dan Yan
- Changjiang Institute of Survey, Planning, Design and Research Co., Ltd, Wuhan 430010, China; Hubei Provincial Engineering Research Center for Comprehensive Water Environment Treatment in the Yangtze River Basin, Wuhan, 430010, China
| | - Tao Liang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
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