Rehabilitation in Intermittent Water Distribution Networks for Optimal Operation
Round 1
Reviewer 1 Report
- In the past, several hydraulic models for the optimization operation of pipe network were proposed. Please add these models and introduce them briefly.
- Please describe the novelty and innovation of this paper.
- Please describe the applicability.
- Please discuss the limitations of practical application.
- Please describe how to apply the results in water management.
Author Response
Reviewer#1 Comments and Responses
Comment: 1. In the past, several hydraulic models for the optimization operation of pipe network were proposed. Please add these models and introduce them briefly.
Response: First, we would like to thank the reviewer for the time and effort spent reviewing our manuscript. We would like to highlight that considering the suggestion of the reviewer this discussion has been added to the paper in section “1. Introduction” and to improve the discussion we have added news references such as:
- Palod, N.; Prasad, V.; Khare, R. Redefining the application of an evolutionary algorithm for the optimal pipe sizing problem. Journal of Water and Climate Change, 2021, 12 (6): 2299–2313. https://doi.org/10.2166/wcc.2021.288.
- Bianchotti, J.D.; Denardi, M.; Castro-Gama, M.; Puccini, G.D. Sectorization for Water Distribution Systems with Multiple Sources: A Performance Indices Comparison. Water, 2021, 13, 131. https://doi.org/10.3390/w13020131.
- Świętochowska, M.; Bartkowska, I.; Gwoździej-Mazur, J. Energy Optimization of the Pumping Station. Sci. Proc., 2021, 9, 37. https://doi.org/10.3390/environsciproc2021009037.
- Capelo, M.; Brentan, B.; Monteiro, L.; Covas, D. Near–Real Time Burst Location and Sizing in Water Distribution Systems Using Artificial Neural Networks. Water, 2021, 13, 1841. https://doi.org/10.3390/w13131841.
- Hu, S.; Gao, J.; Zhong, D.; Deng, L.; Ou, C.; Xin, P. An Innovative Hourly Water Demand Forecasting Preprocessing Framework with Local Outlier Correction and Adaptive Decomposition Techniques. Water, 2021, 13, 582. https://doi.org/10.3390/w13050582.
- Sambito, M.; Piazza, S.; Freni, G. Stochastic Approach for Optimal Positioning of Pumps As Turbines (PATs). Sustainability, 2021, 13, 12318. https://doi.org/10.3390/su132112318.
- Creaco, E.; Galuppini, G.; Campisano, A.; Ciaponi, C.; Pezzinga, G. A Bi-Objective Approach for Optimizing the Installation of PATs in Systems of Transmission Mains. Water, 2020, 12, 330. https://doi.org/10.3390/w12020330.
Comment: 2. Please describe the novelty and innovation of this paper.
Response: The intermittent operation of water distribution networks is poorly studied, despite its common approach in developing countries and all the problems known associated to its application. The subject has very few published papers, as far as we know, what highlights the need to study it as discussed in the paper. The proposed optimized operation is a differential for the intermittent system to operate efficiently with rational energy use and supplying all consumers with the minimum pressure required, even if they are located at unfavorable points (end of network and/or high elevation zones). The proposed procedure shows that resizing can be an alternative to avoid increase in energy consumption in intermittent systems. The study shows that considering only the main network to improve the WDS capacity can lead to great benefits, at a reduced computational effort. We claim that this approach will allowin the decision makers to better plan the investments to improve the system. In addition, joint pump selection and scheduling can achieve a more efficient operation, both in terms of energy consumption and leakage reduction, even better than in continuous operations. Thus, we believe that this endows our manuscript with a reasonable level of novelty and innovation.
Comment: 3. Please describe the applicability. // 5. Please describe how to apply the results in water management.
Response: We believe that the methodology adopted can be used to assist decision-making system managers, especially in extreme situations (e.g. water scarcity), to ensure equitable supply to consumers with lower energy consumption. As much as the continuous operation is desired, still many regions suffer from intermittency, and with the climate changes and the population growth in urban areas, this problem can become more frequent. Thus, this study can support decision-making and select, for example, which pipes should be resized and the operation rules (e.g., pump start and stop) to supply the demand by an optimized operational cost. This could be applied not only to IWS operation, as the resizing of pipes that has the best cost-benefit ratio, to improve the system capacity, but could also be used as a planning tool in CWS and, therefore, meet the increasing demand with lower operational costs. Also quoted, for countries with the same reality as Brazil, wherein the energy matrix is mainly based on energy production by hydroelectric power plants, the smaller daily distribution by smaller daily energy consumption, as observed in the paper, can become an alternative to reduce the overload in the reservoirs of this system, which has multiple uses, also in water supply.
Comment: 4. Please discuss the limitations of practical application.
Response: We believe that the IWS operation should be implemented as a temporary solution to overcome extreme events until the system is able to operate continuously again. As we have highlighted in the “Conclusions”, there are some limitations to address about the associated operational risks and it is necessary to define strategies for entrapped air management, quality control and firefighting that would increase the savings and make the operational risks acceptable in that operation.
Reviewer 2 Report
Dear authors,
the article is extremely interesting and well structured. In order to be able to proceed with the publication, I suggest some changes:
- Separate the results section from the section containing the description of the case study.
- Figures 8 and 9 increase the size of the text and correct in figure 8 the figure letter in the center with (b).
- With reference to the reduction of water losses within the distribution networks as well as using intermittent operation which, as pointed out by you, determines a significant increase in energy consumption and the power required to meet consumer demand (in terms of daily volume) in a shorter period, PATs (Pump as Turbines) can be inserted in order to limit water consumption, acting on pressures and at the same time to recover electricity. To this end, I suggest two recently published articles that refer to the use of PATs (https://doi.org/10.3390/su132112318, https://doi.org/10.3390/w12020330)
Author Response
Reviewer#2 Comments and Responses
Comment: Separate the results section from the section containing the description of the case study.
Response: First, we would like to thank the reviewer for the time and effort spent reviewing our manuscript. The suggestions have been added to the text and now there are different sections for description and results.
Comment: Figures 8 and 9 increase the size of the text and correct in figure 8 the figure letter in the center with (b).
Response: The suggestions have fully been considered.
Comment: With reference to the reduction of water losses within the distribution networks as well as using intermittent operation which, as pointed out by you, determines a significant increase in energy consumption and the power required to meet consumer demand (in terms of daily volume) in a shorter period, PATs (Pump as Turbines) can be inserted in order to limit water consumption, acting on pressures and at the same time to recover electricity. To this end, I suggest two recently published articles that refer to the use of PATs (https://doi.org/10.3390/su132112318, https://doi.org/10.3390/w12020330).
Response: The suggested references have been added to the text in the sections “1. Introduction” and “3.2 ZJ Network results” and we believe that this action has significantly improved the analysis of results and, in a future paper, will help to broaden the results herein obtained.
Round 2
Reviewer 2 Report
Dear authors,
in my opinion the article is almost ready for publication. I only suggest minor revisions to be made:
- Insert the results section 3.1.1. and 3.1.2. in a separate section called results.
- Move to section 3.2. Case study 2: OBCL-1 network immediately after section 3.1. Case study 1: ZJ network
Author Response
Thank you for the observation, which provide a better structure to the paper.
Author Response File: 
Author Response.docx
