Combining Process Modelling and LCA to Assess the Environmental Impacts of Wastewater Treatment Innovations
Round 1
Reviewer 1 Report
Dear Authors,
thanks for your contribution firstly. The paper proposes a life-cycle assessment (LCA) on material and energy flows of different wastewater treatment scenario.
I believe that the paper includes solid content and is well structured, however I suggest revising the manuscript as there are some typos.
The conclusions can be expanded, I like that they are short but not extremely concise. A suggestion may be to include some recommendations in your conclusions.
Finally, the number of references should be increased, please use some new references related to this study. To this end, I suggest you include the following reference which deals with the same topic, but on the entire integrated water system.
LCA methodology for the quantification of the carbon footprint of the integrated urban water system.Sambito, M., Freni, G. Water (Switzerland), 2017, 9 (6), 395.
In total, with these tips it can be a good publication.
Author Response
Dear reviewer,
Thank you for your valuable comments. Here is my point-by-point response:
Point 1: The conclusions can be expanded, I like that they are short but not extremely concise. A suggestion may be to include some recommendations in your conclusions.
Response 1: I have expanded the conclusions with additional new sentences starting on lines 451, 461 and 467 in the manuscript.
Point 2: Finally, the number of references should be increased, please use some new references related to this study. To this end, I suggest you include the following reference which deals with the same topic, but on the entire integrated water system.
LCA methodology for the quantification of the carbon footprint of the integrated urban water system.Sambito, M., Freni, G. Water (Switzerland), 2017, 9 (6), 395.
Response 2: I have included the suggested reference on line 191 in the manuscript in terms of methodology comparison. I could not use this particular study for result comparison, as it deals solely with carbon footprint and does not specify the detailed parameters of the studied wastewater treatment plant (i.e., CH4, N2O emissions).
Sincerely,
Ing. Aleš Paulu
Corresponding author
University of Chemistry and Technology Prague
Technická 5, 160 00 Prague, Czech Republic
+420 721 421 155
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Dear Authors,
I have no substantive comments to the submitted manuscript. However, please review the text again carefully, as it contains minor errors (e.g. in the unit format). In addition, please read the editorial requirements again and correct the references.
Yours faithfully,
Author Response
Dear reviewer,
Thank you for your valuable comment. Here is my response:
Point: I have no substantive comments to the submitted manuscript. However, please review the text again carefully, as it contains minor errors (e.g. in the unit format). In addition, please read the editorial requirements again and correct the references.
Response :
I have corrected these errors in the manuscript:
Line 390:
- “ecluded” to “excluded” in Figure 8
Additionally, I have corrected these errors in the Supplementary material:
Table S1:
- “Centrifuges” to “Centrifuge’s”
- “odour” to “odor”
- “PEa” to “PE”
Finally, I have reviewed and corrected the references in both the manuscript and the Supplementary material according to the 'Instructions for Authors' guidelines.
Sincerely,
Ing. Aleš Paulu
Corresponding author
University of Chemistry and Technology Prague
Technická 5, 160 00 Prague, Czech Republic
+420 721 421 155
Author Response File: Author Response.pdf
Reviewer 3 Report
This paper modeled different wastewater treatment scenarios, including conventional WWT, CEPT, and CEPT with PN/A. LCA was performed on those scenarios, and several important environmental indicators, including GWP, EP, MAETP, etc. were reported. The author found both CEPT and CEPT with PN/A appear to have higher environmental burdens than the conventional WWT. The author did a good job providing mass and energy modeling and detailed data input for 3 scenarios and intercept the results. Also, the comprehensive LCA of different WWTP in the same context would be beneficial to researcher in this field. However, I have the following suggestions for author to consider incorporating into the manuscript.
1. In the abstract, “19.5% and 16.4% higher sum of normalized and weighed environmental indicators”, does the values represented here include the biogenic CO2 or not? This should be clarified.
2. It is suggested to include more quantitative results in the abstract.
3. In supporting information, some of parameters (e.g., electricity consumption) in Table S1 were given in a unit of kwh/yr. In the mass and energy model, the unit of electricity was given in kwh/day. However, the operating day was not specified in the manuscript. What’s the assumption for operating day?
4. For fig 8, it is suggested to represent the weighted results using stacked bars (legends are environmental indicators such as GWP, EP, etc) such that readers could have a better understanding of the contribution of impact categories to the total impact.
5. It is suggested to address the contributions of this study to the existing literature.
Author Response
Dear reviewer,
Thank you for your valuable comments. Here is my point-by-point response:
Point 1+2: In the abstract, “19.5% and 16.4% higher sum of normalized and weighed environmental indicators”, does the values represented here include the biogenic CO2 or not? This should be clarified.
It is suggested to include more quantitative results in the abstract.
Response 1+2: I have included more quantitative results and at the same time clarified the inclusion of biogenic CO2 starting on line 19 in the abstract. Unfortunately, I could not have included a higher amount of quantitative results due to the journal´s 200-word limit in the abstract.
Point 3: In supporting information, some of parameters (e.g., electricity consumption) in Table S1 were given in a unit of kwh/yr. In the mass and energy model, the unit of electricity was given in kwh/day. However, the operating day was not specified in the manuscript. What’s the assumption for operating day?
Response 3: I have included a clarification for operating day referencing these parameters, starting on line 48 in the Supplementary material.
Point 4: For fig 8, it is suggested to represent the weighted results using stacked bars (legends are environmental indicators such as GWP, EP, etc) such that readers could have a better understanding of the contribution of impact categories to the total impact.
Response 4: I have changed the graph type in Figure 8 (line 390) in the manuscript to stacked bars as suggested.
Point 5: It is suggested to address the contributions of this study to the existing literature.
Response 5: I have added a new paragraph (starting on line 467) at the end of the conclusions in the manuscript highlighting the approach of the study and its contribution to current literature.
Sincerely,
Ing. Aleš Paulu
Corresponding author
University of Chemistry and Technology Prague
Technická 5, 160 00 Prague, Czech Republic
+420 721 421 155
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Dear Authors,
the suggested changes have been made therefore now, in my opinion, the paper is ready for publication.
Reviewer 3 Report
All my concerns have been addressed and I'd recommend this manuscript for publication.
