Experience of Application of Natural Treatment Systems for Wastewater (NTSW) in Livestock Farms in Canary Islands

Round 1

Reviewer 1 Report

The content of your submitted paper is timely and the valuable results were obtained. Your obtained information will contribute the application of NTSW in livestock farms. But, there are some unclear points in your paper. I have judged minor revision is required before accepting your paper. The followings are weak and unclear points of your paper.

1.      You must use Figure and Table instead of figure and table in the text.

2.      You must write the operational condition of rotary screen including rotating speed. How is the final treatment methods for screen residue?

3.      Fig. 9  Please pay attention to the flow of waste through rotary screen. Farm wastewater is send to the rotary screen and the wastewater passing rotary screen is then to send to reception tank. Please change the flow of waste shown in Fig.9.

4.      It is better to use “holding tank” instead of reception tank.

5.      Table 1  Unit of COD must be mg/L, not ppm.

6.      Did you use the water impermeable sheet for the construction of pond and SSFCW? If so, you must describe this sheet in M&M. If you did not use this sheet, a lot of wastewater was lost through underground infiltration. Did you consider this infiltration in your mass balance.

7.      Vegetation in the SSFCW will play an important role for COD and nitrogen removal. You must mention the species grown in SSFCW and its function in detail.

8.      Fig. 10-27  It is better to use time base instead of samples. You have only showed the obtained results in Figures. It is necessary to show your results in reasonable ways.

9.      Discussion is poor. It is required for you to show your superiority of your research work by comparing your results with other results. I strongly advise you to make clear your new findings through the comparison of your obtained results and the results reported by other researchers.

10.  In developing countries, effluent regulation on N and P is becoming strict. You did not touch the nutrient removal in your test plants.　Please describe the effluent regulation on N and P in Spain

11.    Please check the following English.

ü  Line 7, 9  The usage of “when” is inadequate.

ü  Line 20  in where??

ü  Line 92  complete mixer digester →　complete mixing digester

ü  Line 148  it is made mention  ???

ü  Line 188, 210  It is better not to use “we” in the academic paper.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

1) Provide a new table that compares the different technologies (natural and artificial) used for treating wastewater from real pig livestock farms, in small communities, and compare their performances, conditions, advantages and limitations.

2) State the objectives of this work in 5 sentences.

3) The novelty of this work is missing - state that in 5-6 nice sentences.

4) Compare the performance of the AD system with other ADs in the form of a new table and state all the conditions.

5) Write the mechanism of pollutant removal in constructed wetlands with the subsurface flow.

6) How can Table 2. Relations between variables of Plants, be used by other researchers and what are the constraints. Write the practical applications in 4-5 sentences.

7) Discuss the real role and mechanism of the amount of salts present in a slurry and how did it affect the results?

8) Compare the COD removal efficiency with other systems in the form of a table and show all the reactions for C conversion to other end products.

9) Under what conditions can we use Cascade flow digesters? Why - explain in detail.

10) Check REF formatting manually. A lot of mistakes can be seen. 

11) The comments from the reviewers and the editors of WATER should be INCORPORATED in the revised manuscript. Therefore, please read the decision letter till the very end. Do not leave any comment unanswered. Also, the author's response file should be DETAILED with the author's response, i.e. it has to show all the new text added, the new changes made to the graphs, tables, etc. Please don't write - DONE, OK, Thanks, Modified, See page XX, we answered it, we implemented it, etc.  

11) Conclusions should be after the Figures.

12) Show only a max of 12 figures and move the remaining to the supplementary info. A lot of graphs and the MS looks like a Master thesis or a report to a funding agency.

Too many figures, showing the same info. Moderate revision is required.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf