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  • Sedolfo Carrasquero-Ferrer 1,*,
  • Jean Pino-Rodríguez 1 and
  • Altamira Díaz-Montiel 2

Reviewer 1: Fethi Kooli Reviewer 2: Anonymous Reviewer 3: Anonymous

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

One concern is the use of the kinetic equation.

Author Response

Comment 1:One concern is the use of the kinetic equation

 The procedure used to determine the constant and kinetic equation is widely applied in wastewater treatment. Recently, Koundle et al. (2024) used this procedure to determine the degradation kinetics of tetracycline. These authors describe the procedure as analyzing the correlations of zero-order, first-order, and second-order reactions; the best-fitting correlation coefficient determines the reaction order. In the case of their research, it was first-order.

 Koundle, P., Nirmalkar, N., Momotko, M., Makowiec, S., & Boczkaj, G. (2024). Tetracycline degradation for wastewater treatment based on ozone nanobubbles advanced oxidation processes (AOPs) – Focus on nanobubbles formation, degradation kinetics, mechanism and effects of water composition. Chemical Engineering Journal, 501, 156236. https://doi.org/10.1016/j.cej.2024.156236

Reviewer 2 Report

Comments and Suggestions for Authors

This research focused on treating wastewater from a canned soup processing plant using 11 sequencing batch reactors. However, what's the main contribution or innovation of this paper? After careful consideration, it is not suggested that the paper be considered for publication in its current form. 

Specific suggestions:

1. The logical relationship and key points in the introduction section are not clear, and should be reduced to 4-5 paragraphs. It is recommended to summarize the advantages and disadvantages of the SBR process in comparison with other commonly used processes, as well as the drawbacks of traditional treatment processes in treating food processing wastewater, highlighting the advantages of SBR in the author's country.

2. The characteristics of food processing wastewater are only mentioned in a simple sentence in the introduction section, and the differences between food processing wastewater and other wastewater should be highlighted in terms of water quality and quantity.

3. Lack of basic data for the start-up phase of the unit, such as MLSS, MLVSS, SV30, SVI30, biological phase pictures, etc.

4. Please explain the reasons and significance of the classification of COD into many categories, as well as the wastewater discharge pathways and resource utilization pathways.

5. The authors chose actual food processing wastewater as the influent, however section 3.4 adjusted the C/N with urea and monopotassium phosphate, what is the significance of this? The object of the study should focus on the characteristics of the wastewater itself.

6. There are many obvious errors in the details of the article, and the authors should strengthen the revision of the details of the paper. For example, "TCO" in "3.5 Performance of the SBR at different TCO and SRT" and "CDOo" and "CDOf" in Figure 3.

7. The parameter regulation stage is all about describing the occurrence of the experimental phenomenon, and does not explain the mechanism by which this phenomenon occurs. It is suggested that the author strengthen the supplement in terms of mechanism.

8. In addition to summarizing the research findings and results, the "Conclusion" section should also demonstrate the theoretical and practical significance of the entire paper.

Author Response

Dear Editorial Team,

 

Below are the responses to the revisions made by Reviewer No. 2.

 

Dr. Sedolfo Carrasquero Ferrer

 

Response to the Observations Made by the reviewers

 

Reviewer No. 2

 

  1. The logical relationship and key points in the introduction section are not clear, and should be reduced to 4-5 paragraphs. It is recommended to summarize the advantages and disadvantages of the SBR process in comparison with other commonly used processes, as well as the drawbacks of traditional treatment processes in treating food processing wastewater, highlighting the advantages of SBR in the author's country.

 

The introduction was adjusted according to the referee's suggestions. It is worth noting that it was reduced to 5 paragraphs.

 

  1. The characteristics of food processing wastewater are only mentioned in a simple sentence in the introduction section, and the differences between food processing wastewater and other wastewater should be highlighted in terms of water quality and quantity.

 

 

The suggested corrections were incorporated into the paragraph, which now reads as follows:

 

Wastewater from the food processing industry exhibits unique characteristics that distinguish it from other types of wastewaters in terms of both quality and quantity. In terms of quality, it often high concentrations of soluble organic compounds that must be treated to reduce pollution before discharge, especially given increasing regulations on effluent control and disposal [7,8]. Common characteristics of effluents from food industries include chemical oxygen demand (COD), biological oxygen demand (BOD), dissolved solids, phosphates, nitrates, surfactants, fats, oils, and intense color with a fluctuating pH [4,9]. (Pešević, Haddaji et al., 2023, Yasin et al., 2020, Preethi et al., 2019). Regarding quantity, the generation of wastewater in this industry is highly dependent on production volumes and processing methods, often resulting in intermittent discharges with high flows during specific times of the day. These features make food processing wastewater require specialized treatment methods that may not be applicable or necessary for other types of industrial or domestic wastewater (Sanghamitra et al. 2021; Rai y Sinha , 2023)

 

Sanghamitra, P., Mazumder, D., & Mukherjee, S. (2021b). Treatment of wastewater containing oil and grease by biological method- a review. Journal Of Environmental Science And Health Part A, 56(4), 394-412. https://doi.org/10.1080/10934529.2021.1884468

 

Rai, D., & Sinha, S. (2023). Impact of different anode materials on electro-Fenton process and tannery wastewater treatment using sequential electro-Fenton and electrocoagulation. Chemosphere, 336, 139225. https://doi.org/10.1016/j.chemosphere.2023.139225

 

Pešević, D., Knežević, N., & Marković, M. (2019). QUALITY ASSESSMENT OF VEGETABLE OIL EFFLUENT DISCHARGED INTO SAVA RIVER. Archives For Technical Sciences, 2(21), 85-93. https://doi.org/10.7251/afts.2019.1121.085p

 

Haddaji, C., Chatoui, M., Rifi, S. K., Ettaloui, Z., Digua, K., Pala, A., Anouzla, A., & Souabi, S. (2023). Performance of simultaneous carbon, nitrogen, and phosphorus removal from vegetable oil refining wastewater in an aerobic-anoxic sequencing batch reactor (OA-SBR) system by alternating the cycle times. Environmental Nanotechnology Monitoring & Management, 20, 100827. https://doi.org/10.1016/j.enmm.2023.100827

 

Yasin, N. M. F. M., Hossain, M. S., HPS, A. K., Zulkifli, M., Al-Gheethi, A., Asis, A. J., & Yahaya, A. N. A. (2020). Treatment of Palm Oil Refinery Effluent Using Tannin as a Polymeric Coagulant: Isotherm, Kinetics, and Thermodynamics Analyses. Polymers, 12(10), 2353. https://doi.org/10.3390/polym12102353

 

Preethi, V., Ramesh, S. T., Gandhimathi, R., & Nidheesh, P. V. (2019d). Optimization of batch electrocoagulation process using Box-Behnken experimental design for the treatment of crude vegetable oil refinery wastewater. Journal Of Dispersion Science And Technology, 41(4), 592-599. https://doi.org/10.1080/01932691.2019.1595640

 

  1. Lack of basic data from the initial phase of the unit: Basic data for the startup phase, such as MLSS, MLVSS, SV30, SVI30, images of the biological phases, etc., are missing.

 

During the acclimatization phase, operational parameters were measured to monitor the behavior of the sludge during this period. The values corresponding to the end of the acclimatization process are provided for the reader's reference in the following paragraph:

 

At the end of the acclimation period, the reactor operated under stable and controlled conditions, demonstrating its efficiency in wastewater treatment. The operational parameters were as follows: SV30 of 370 ± 20 mL/L, indicating an adequate sludge settling capacity, and an SVI30 of 107 ± 3 mL/g, confirming good sludge compaction and quality with a low risk of bulking. The concentration of total suspended solids in the mixed liquor (SSTML) was 3502 ± 128 mg/L, while the volatile suspended solids (VSSML) reached 2515 ± 185 mg/L, representing a robust biomass with a predominant organic fraction. These results highlight the system's ability to maintain an optimal balance between sludge settleability and biological activity, ensuring an efficient biodegradation process of the organic matter in the influent

 

It is worth noting that no images of the biological phases were taken during this process.

 

  1. COD Classification: Please explain the reasons and relevance of classifying COD into various categories, as well as the wastewater discharge pathways and the potential routes for its utilization as a resource.

 

The fractionation of COD (Chemical Oxygen Demand) involves classifying it into different categories based on the nature and biodegradability of the organic matter present in wastewater. This classification includes fractions such as soluble COD (CODs) and particulate COD (CODp), as well as subcategories of biodegradable COD (CODb) and non-biodegradable COD (CODnb). The relevance of performing this fractionation lies in its ability to provide detailed information about the composition of the organic load, enabling the design and optimization of biological treatment processes. For instance, identifying the biodegradable fraction helps evaluate the efficiency of aerobic or anaerobic degradation processes, while the non-biodegradable fraction allows for estimating the accumulation of matter in the system. Additionally, differentiating between soluble and particulate COD is crucial for understanding the requirements of physical-chemical and biological treatments, as well as the time needed for the efficient removal of each fraction. Overall, this analysis is essential for developing precise strategies to control and improve wastewater treatment systems. A paragraph was added to this section to clarify the reader's doubts.

 

 

The Venezuelan regulations establish specific parameters for the discharge of wastewater, distinguishing between discharges into natural water bodies (such as rivers, lakes, and seas) and discharges into public sewer systems (sewers). For discharges into natural water bodies, the permissible limits are stricter as they aim to protect water quality and minimize environmental impacts. These parameters include maximum concentrations of pollutants such as Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), total suspended solids (TSS), fats and oils, heavy metals, and other toxic compounds.

In the case of discharges into sewer systems, the limits are generally less stringent since the wastewater will subsequently be treated in centralized treatment plants. However, the regulations also establish clear restrictions to prevent damage to the sewer infrastructure and ensure the efficiency of treatment plants. These include limits for settleable solids, fats and oils, pH, and concentrations of corrosive or toxic substances that could interfere with biological treatment processes.

 

The discharge pathways in the effluent's country of origin were explained in the text for the reader's understanding.

 

The reuse of treated water for irrigation is of great importance, particularly after a polishing treatment that effectively reduces color and turbidity. This final treatment stage enhances the aesthetic and physical quality of the water, ensuring that it meets the necessary standards for agricultural use. Reducing color eliminates any visual contamination that might affect the perception of water quality, while lowering turbidity minimizes the presence of suspended particles that can clog irrigation systems and negatively impact soil aeration and plant growth. Furthermore, the reuse of treated water for irrigation promotes sustainable water management, alleviating pressure on freshwater resources, especially in regions prone to water scarcity. This practice not only supports agricultural productivity but also contributes to the circular economy by transforming wastewater into a valuable resource for irrigation, fostering environmental protection and long-term water resource conservation.

 

A paragraph was included indicating that the water could be used for irrigation after a polishing treatment.

 

 

  1. Significance of Adjusting the C/N Ratio: The authors used real wastewater from food processing as influent. However, in section 3.4, the C/N ratio was adjusted using urea and monopotassium phosphate. What is the significance of this adjustment? The focus of the study should be on the intrinsic characteristics of the wastewater.

 

Indeed, real wastewater was used throughout the study. However, in the initial phase, the decision was made to improve the C/N/P ratio due to a nutrient deficit in the industrial effluent. This first stage of the experiment aimed to determine whether the addition of macronutrients from an external source would improve the removal of the evaluated physicochemical parameters. The results indicated that the addition of these external compounds was unnecessary, so in the subsequent phase, the experimental evaluation was conducted using the wastewater's original characteristics.

The authors believe it is important for readers to know that a preliminary stage with macronutrient addition was performed to demonstrate that microorganisms can adapt to effluents with nitrogen and phosphorus deficits.

 

  1. Obvious Errors in Article Details: There are numerous evident errors in the article's details. The authors should strengthen the review of these details. For example, "TCO" in the section "3.5 Performance of the SBR at different TCO and SRT" and "CDOo" and "CDOf" in Figure 3.

 

All abbreviations and acronyms in the document were reviewed to address the errors indicated by the reviewer. It is worth noting that every Table and Figure now includes a legend explaining the meaning of the acronyms.

 

  1. Lack of Explanation of Mechanisms in the Parameter Regulation Phase: The parameter regulation phase is limited to describing the experimental phenomena but does not explain the mechanism behind these phenomena. It is suggested that the authors strengthen this aspect with explanations of the mechanisms.

 

Paragraphs were added to explain the mechanisms behind the removal of organic matter, nitrogen, phosphorus, and color throughout the study, detailing the principles of these mechanisms.

 

 

Vázquez, C. M. L., Méndez, G. B., García, H. A., & Carrillo, F. J. C. (2017). Tratamiento biológico de aguas residuales: Principios, modelación y diseño. Water Intelligence Online, 16, 9781780409146. https://doi.org/10.2166/9781780409146

 

  1. Expand the "Conclusion" Section: In addition to summarizing the findings and results of the research, the "Conclusion" section should also demonstrate the theoretical and practical relevance of the entire study.

The conclusions were enhanced to address this recommendation.

 

Reviewer 3 Report

Comments and Suggestions for Authors

Report

Manuscript Number: sustainability-3372854

Title: Sequence batch reactor: a sustainable wastewater treatment option for the canned vegetables industry

The manuscript focused on treating wastewater from a canned soup processing plant using sequencing batch reactors (SBR). The main problem was the high load of organic matter and nutrients, especially chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN). Additionally, the objective was to evaluate the efficiency of SBR under different operational cycle times (OCT) and sludge retention times (SRT). The experiment tested combinations of 6, 8, and 10-hour OCT and 15 and 25-day SRT, with and without adding macronutrients However, there are revision requirements before possible acceptance, and the author is asked to revise them.

1.     The abstract should come in with a background to the objective, methodology, results, contribution, and novelty. The current abstract is an explanation of data and results, but not appropriate for the academic journal paper. In the abstract, the authors should clearly state why this study is necessary and new to the field.

2.     The novelty of the work should be clearly emphasized in the last paragraph of the introduction.

3.     What is the evidence (citation) for equation (1), and also the values ​​used in Table 2?

4.     English needs to be improved. There are typos and grammatical errors within the manuscript that need to be addressed.

5.     The highlights should be a list of major, specific accomplishments, not a list of tasks performed.

6.     The presentation and also the depth of the analysis need to be improved.

 

7.     All abbreviations mentioned within the manuscript should be carefully reviewed.

Comments on the Quality of English Language

No comment.

Author Response

Comment 1: The abstract should include a context leading to the objective, methodology, results, contribution, and novelty. The current abstract is an explanation of data and results, but it is not appropriate for a journal article. In the abstract, the authors should clearly indicate why this study is necessary and what new contributions it brings to the field.

Response: The suggested changes by the reviewer were made to the abstract.

Comment 2: The novelty of the work must be clearly highlighted in the last paragraph of the introduction.

Response: The paragraph on the novelty of the work was added at the end of the introduction.

Comment 3: What is the evidence (citation) for Equation (1) and the values used in Table 2?

Response: The references were added.

Comment 4: The English needs improvement. The manuscript contains typographical and grammatical errors that must be corrected.

Response: The English was improved.

Comment 5: The highlights should be a list of specific and relevant achievements, not a list of tasks performed.

Response: The conclusions and highlights of the article were improved.

Comment 6: Both the presentation and the depth of the analysis need improvement.

Response: Paragraphs explaining the obtained removal mechanisms were added.

Comment: 7: All abbreviations mentioned in the manuscript should be carefully reviewed.

Response: The abbreviations were carefully reviewed.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I have read the manuscript after revision, the authors have addressed the concerns of the reviewer

Reviewer 2 Report

Comments and Suggestions for Authors

I have found that all my comments and suggestions for improvement have been adequately addressed. I consider this paper can be accepted as is now.