Comparison of Organic Matter Properties and Disinfection By-Product Formation between the Typical Groundwater and Surface Water

Round 1

Reviewer 1 Report

Rationality for the study requires a comparison to the work of the others in the same field. I suggest a Table in the introduction or in the results and discussion include such kind of comparison.

English revision is advised 

Author Response

Response to Reviewers’ comments

 

Reviewer#1

Rationality for the study requires a comparison to the work of the others in the same field. I suggest a Table in the introduction or in the results and discussion include such kind of comparison.

• Response: Thanks for your constructive suggestion. The comparison of this study with others in the similar field has been provided as follows. This table has also been supplemented into the Introduction section, and the following description has also been enclosed.

“Here, similar studies which also focused on the relationships between source water and DBP formation are summarized and concluded their difference with our study. However, there is limited study focused on their different DOM characteristics and DBPFP, especially for the 3D-EEM charter and DBP toxicity.”

Table 1 The comparison of this work with other similar studies

Source water	Similar Results	Difference	Reference
SW and GW using Yellow River water and	SW achieved much higher DBP concentrated in the finished water	Lack of tap water data and toxicity evaluation and did not compare the DBPs with the source water NOM characteristics.	(Hou et al., 2012)
Sea (SWR), river (RWR) and reservoir(RVR) water	The THMFP：RSR > SWR > RVR for chlorination； SWR > RSR > RVR for ClO2 treatment.	Lack of tap water data and toxicity data and did not compare the DBPs with the source water NOM characteristics.	(Padhi et al., 2019)
Taihu Lake water	19 possible precursors of the discovered DBPs were detected, with the aromatic compounds being a major group	Mainly focused on the unknown DBPs detection and only one surface source water.	(Zhai et al., 2017)
Reservoir water	The source, types and humification degree of DOM affect the formation of DBPs.	Only the surface source water and lack of the toxicity evaluation.	(Xu et al., 2021)

References

Hou, Y., Chu, W., Ma, M., 2012. Carbonaceous and nitrogenous disinfection by-product formation in the surface and ground water treatment plants using Yellow River as water source. J. Environ. Sci. 24, 1204–1209. https://doi.org/https://doi.org/10.1016/S1001-0742(11)61006-1

Padhi, R.K., Subramanian, S., Satpathy, K.K., 2019. Formation, distribution, and speciation of DBPs (THMs, HAAs, ClO2−,andClO3−) during treatment of different source water with chlorine and chlorine dioxide. Chemosphere 218, 540–550. https://doi.org/https://doi.org/10.1016/j.chemosphere.2018.11.100

Xu, X., Kang, J., Shen, J., Zhao, S., Wang, B., Zhang, X., Chen, Z., 2021. EEM–PARAFAC characterization of dissolved organic matter and its relationship with disinfection by-products formation potential in drinking water sources of northeastern China. Sci. Total Environ. 774, 145297. https://doi.org/https://doi.org/10.1016/j.scitotenv.2021.145297

Zhai, H., He, X., Zhang, Y., Du, T., Adeleye, A.S., Li, Y., 2017. Disinfection byproduct formation in drinking water sources: A case study of Yuqiao reservoir. Chemosphere 181, 224–231. https://doi.org/https://doi.org/10.1016/j.chemosphere.2017.04.028

 

English revision is advised

• Response: Thanks for your kind suggestion. The English throughout this manuscript has been carefully checked and updated.

Author Response File: Author Response.pdf

Reviewer 2 Report

This study aimed to investigate the formation of DBP for 2 water sources used in the treatment plants, respectively GW and SW. An interesting technique, namely the three-dimensional excitation emission matrix (3D-EEM), was used to characterize the treated effluent from the water treatment plants. In addition, the cytotoxicity of the formed DBPs was also calculated.

Overall, the paper is well written and interesting, but there are still some issues that need to be addressed.

1. Introduction section. The novelty of the paper should be specified here.
2.  Materials and methods section.  It should be supplemented with the inffluent characteristics of the treatment plant in order to make subsequent correlations.
   
3. Why it was necessary to filter the tap water?
4. Conclusions section. It needs to be improved, it needs to reflect the content of the whole work.

Author Response

Reviwer#2

This study aimed to investigate the formation of DBP for 2 water sources used in the treatment plants, respectively GW and SW. An interesting technique, namely the three-dimensional excitation emission matrix (3D-EEM), was used to characterize the treated effluent from the water treatment plants. In addition, the cytotoxicity of the formed DBPs was also calculated.

Overall, the paper is well written and interesting, but there are still some issues that need to be addressed.

1. Introduction section. The novelty of the paper should be specified here.

• Response: Thanks for your suggestion. To specify the novelty of this study, in the Introduction section, this study was compared with similar studies which also focused on the relationships between source water and DBP formation are summarized and concluded their difference with our study as shown in Table1. However, there is limited study focused on their different DOM characteristics and DBPFP, especially for the 3D-EEM charter and DBP toxicity.

Table 1 The comparison of this work with other similar studies

Source water	Similar Results	Difference	Reference
SW and GW using Yellow River water and	SW achieved much higher DBP concentrated in the finished water	Lack of tap water data and toxicity evaluation and did not compare the DBPs with the source water NOM characteristics.	(Hou et al., 2012)
Sea (SWR), river (RWR) and reservoir(RVR) water	The THMFP：RSR > SWR > RVR for chlorination； SWR > RSR > RVR for ClO2 treatment.	Lack of tap water data and toxicity data and did not compare the DBPs with the source water NOM characteristics.	(Padhi et al., 2019)
Taihu Lake water	19 possible precursors of the discovered DBPs were detected, with the aromatic compounds being a major group	Mainly focused on the unknown DBPs detection and only one surface source water.	(Zhai et al., 2017)
Reservoir water	The source, types and humification degree of DOM affect the formation of DBPs.	Only the surface source water and lack of the toxicity evaluation.	(Xu et al., 2021)

References

Hou, Y., Chu, W., Ma, M., 2012. Carbonaceous and nitrogenous disinfection by-product formation in the surface and ground water treatment plants using Yellow River as water source. J. Environ. Sci. 24, 1204–1209. https://doi.org/https://doi.org/10.1016/S1001-0742(11)61006-1

Padhi, R.K., Subramanian, S., Satpathy, K.K., 2019. Formation, distribution, and speciation of DBPs (THMs, HAAs, ClO2−,andClO3−) during treatment of different source water with chlorine and chlorine dioxide. Chemosphere 218, 540–550. https://doi.org/https://doi.org/10.1016/j.chemosphere.2018.11.100

Xu, X., Kang, J., Shen, J., Zhao, S., Wang, B., Zhang, X., Chen, Z., 2021. EEM–PARAFAC characterization of dissolved organic matter and its relationship with disinfection by-products formation potential in drinking water sources of northeastern China. Sci. Total Environ. 774, 145297. https://doi.org/https://doi.org/10.1016/j.scitotenv.2021.145297

Zhai, H., He, X., Zhang, Y., Du, T., Adeleye, A.S., Li, Y., 2017. Disinfection byproduct formation in drinking water sources: A case study of Yuqiao reservoir. Chemosphere 181, 224–231. https://doi.org/https://doi.org/10.1016/j.chemosphere.2017.04.028

 

2. Materials and methods section.  It should be supplemented with the influent characteristics of the treatment plant in order to make subsequent correlations.

• Response: Thanks for your constructive suggestion. The influent characteristics of these two treatment plants has been provide.

 

3. Why it was necessary to filter the tap water?

• Response: The filtration process was mainly due to the requirement of the GC-MS instruments.

 

4. Conclusions section. It needs to be improved, it needs to reflect the content of the whole work.

• Response: Thanks for your kind suggestion. The conclusion has been improved.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The authors made the suggested additions. From my point of view the paper can be accepted for publication in revised form.

Author Response

Response: Thanks for your kind suggestion to improve the quality of our manuscript.

Author Response File: Author Response.docx