Potential Benefits and Disbenefits of the Application of Water Treatment Residuals from Drinking Water Treatment Processes to Land in Scotland: Development of a Decision Support Tool

Round 1

Reviewer 1 Report

The manuscript entitled ‘‘Potential benefits and disbenefits of the application of Water Treatment Residuals to land: Development of a Decision Support Tool” by Minto et al. is reviewed. The authors systematic reviewed the already available literature and attempted to develop a DST to assist decision making, which is of significant importance. The manuscript, however, has some critical problems, that need to be addressed for a possible publication in this journal. Potential suggestions for improving the manuscript are provided below.

 

Comments

1. Although this manuscript is submitted as a research article, I strongly believe that this work should be rather considered as a review article.
2. Since the proposed application of this work is limited to Scotland, a more specific name would be much better.
3. Except the quality of language used for the presentation, I personally feel like the manuscript is prepared too irresponsibly with countless mistakes everywhere, which is unacceptable for a quality journal. The above-mentioned mistakes includes, but not limited to

1. Lack of references for several statements throughout the manuscript (e.g., lines 68-69, 182, 199, 310-314, and many more).

2.    I didn’t see tables 5 and 6 anywhere in the manuscript (not even a mention). Rather, the authors directly jumped from Table 4 to Table 7.

3.    Further, I personally don’t agree with the authors using tables to discuss other published reports (in a same way they did in the rest of the manuscript). The use of footnotes throughout the tables are also terrible.

4. Countless typos are found throughout the manuscript, which includes lack of spaces between words (e.g., lines - 329, sludgederived, 338 - wellestablished, table 13 - containhigh), values (e.g., line 190 - >7.5, 191 - >6.3), superscript/subscripts (e.g., Table 8, m3 ha-1 & 2.5 g kg-1), and many more. There is even an occasion in which the authors wrongly used zero (0), instead of the alphabet “O” in table 7 (i.e., KMnO₄ is wrongly written as KMn0₄).

5.    Please be consistent on units. For example, do not use “kg^-1” and “/kg”. Either use one style, ideally the former.

4. Lines 54-63; I wonder if the bullet points provided is really relevant which demands a mention in this report, especially by considering the limited to almost no discussion of them in the rest of the manuscript?
5. Line 63; “(exemptions – paragraph 9, 7).”: This is really confusing. Is the author’s means paragraphs 7 and 9 of the "Waste Management Licensing (Scotland) Regulations 2011"? Further there is a spelling mistake in the beginning of the same sentence.
6. Table 2: last entry – What is WWTRs stands for? Please specify it, or other abbreviations, on the first use.
7. Line 70; “aluminium (Al) salts” – please specify the Al salts, if they are not too many.
8. Line 111: The sentence has serious problems.
9. Line 118: “12.0 ± 18.7 g/kg” - Is this true that the error bars (i.e., 18.7) in this case is larger than the actual value (i.e., 12.0)?
10. Table 3: Why P₂O₅, K₂O, SO₃. And MgO are in brackets?
11. Lines 345-347: It may not appropriate to rank/promote a specific review over others.
12. Both figures need to be improved for a better visibility of data, especially on the white text on golden background.
13. The use of headings throughout the manuscript shall be better organized for clarity.
14. Using headings on the conclusion section is highly discouraged. Further, the conclusion section itself is too long.

Author Response

Thank you for your comments, please see response to your comments attached as a word document. 

Author Response File: Author Response.pdf

Reviewer 2 Report

The article assesses the possibility of using Residues from Water Treatment (WTR) into the soil for the purposes of the circular economy. The publication is of a review nature and is an analysis of the results of empirical research previously published in the world literature. Due to the multiplicity of environmental conditions for the application of WTR to the ground, the authors developed a decision support tool (DST). DST is dedicated to decision-makers and stakeholders to help them in the decision-making process regarding the applicability of WTR in a specific location. The DST was developed on the basis of conclusions drawn from the presented literature review.

 

Some corrections should be made in the article according to the points below.

1. The article does not discuss the legal conditions of the European Union and possibly other countries that allow the use of WTR on land. Only certain conditions related to Scotland are listed (verses 55-63) without their in-depth analysis, e.g. whether there are legal regulations or other guidelines that specify physico-chemical parameters that limit the possibility of using WTR on land,

2. In Table 1, the authors provide a summary of the production and reuse/disposal of WTR in Scotland. It would be interesting to present such data for other countries,

3. The presentation of units should be unified. In most cases there is e.g. g∙kg-1, but g/kg also occurs (e.g. lines 117-118),

4. Incorrect table numbering (tables 5,6 are missing),

5. Table 11 referenced in the text is missing (line 397)

6. Inconsistency in the text (lines 401-404). What are Potentially Toxic Elements (PTEs)? Which table are the authors referring to? Are the legal provisions regulating the possibility of using WTR and sewage sludge on the land the same?

7. Should microbiological analyzes be performed when performing qualitative characterization of WTR? If so, which indicator species? In what water treatment processes can Giardia parasites appear in WTR (line 426). How to calculate the probability of infection risk? (line 429)

Author Response

Thank you for your comments, please see responses to your comments attached as a word file. 

Author Response File: Author Response.pdf

Reviewer 3 Report

Manuscript ID: 2313148

Title: Potential benefits and disbenefits of the application of Water Treatment Residuals to land: Development of a Decision Sup-3 port Tool

Sustainability

 

This work provides an overview on different aspects related to the application of WTRs to land by means of an exhaustive review. In addition, according to the data found in literature, the authors develop a user-friendly Decision Support Tool. The manuscript deals about a current topic and include many interesting data; however, in my opinion, the manuscript could be improved.

 

-      Since the origin of the sludge is not obvious, I suggest modifying the title as follows: “Application of Water Treatment Residuals from drinking water treatment processes to land: Development of a Decision Sup-3 port Tool”.

-      For the same reason commented above, modify Line 8 as follows: “Water Treatment Residuals (WTRs) are obtained from the drinking water treatment processes, and are a mixture…”

-      My major concern is about the extrapolation of the conclusions obtained, i.e., there is a lot of information about Scottish policy (Lines 54-63), but the EU policy (and also UN regulations and global regulations) is also of great interest regarding water treatment residuals. Therefore, the introduction should include more information on this topic, instead of being focused specifically on Scotland.

-      There are many mistakes of format. The manuscript is not adapted to the journal requirements (tables, paragraphs, references…). There are also many typos, for example: subscripts (line 103, line 114, line 116, line 362…), the species must be written in cursive (line 354, line 426), the acronym PTE is not explained, the tables are not correctly numbered, the titles of the sections are not numbered so it is very difficult to undertint the manuscript organization…

-      Line 246 is not clear, “author”, who?

-      Line 430, “under paragraph 7…”, this is not clear.

-      Line 11 is incomplete, “resulting in…” ?

-      Table 10: include the references in this table

-      The text in tables 2, 7, 8 and 9 have to be shortened, since they are very cumbersome.

-      Lines 426-428: “found that levels of the parasite Giardia in WTR, produced under certain treatment processes, could be high enough to generate a health risk if the WTR contaminated water supplies”. I do not understand what treatment processes could favour the increase of this parasitic microorganism, is that referred to Giardia cysts? Please clarify this sentence.

Author Response

Thank you for your comments, please see responses to your comments attached as a word file.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

I consider that the manuscript can be acepted in the present form