Feasibility Study of Applying Anaerobic Step-Feeding Mode for the Treatment of High-Strength Wastewater in Granular Sequencing Batch Reactors (GSBRs)
Round 1
Reviewer 1 Report
Dear Authors,the manuscript is very interesting, however it is necessary to clarify some aspects: 1- We speak generically of COD reduction, however it would be better to also identify some specific pollutants that can be more precise "markers" for water treatment (eg PAHs, etc.); 2- It is not clear what the microbial population is (if there is a consortium of bacteria, etc.) which allows the reduction of COD, NH4 and PO4 or if it is a simple physical adsorption; 3- Some physical parameters must be clarified in order to also determine the effective application of granular sequencing batch reactors (GSBRs) such as pH, operating temperature, any back-pressure, etc.
Best wishes
Author Response
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Author Response File: Author Response.docx
Reviewer 2 Report
Comments to the manuscript “Feasibility study of applying anaerobic step-feeding mode for the treatment of high-strength wastewater in granular sequencing batch reactors (GSBRs)” (processes-2100808)
Some specific comments are following
1. The title mainly focused on the operation of R2 in stage 3 which was a partial results of your work. I recommend to modify the title to cover all key finding such as granular stability, comparison of conventional GSBR and anaerobic step feeding GSBR, etc.
2. The pain point of conventional GSBR for COD and nutrients removal should be clearly stated. How the anaerobic step-feeding SBR can improve the biological removal mechanisms (i.e., P uptake, P release, nitrification, denitrification) should be explained.
3. The SBR cycle configuration with (step) feed strategy of R1 and R2 should be included in Figure 1 for easy understanding.
4. The effluent NO2-N and NO3-N should be presented in Table 2 to clarify the performance of nitrification and denitrification of the systems. In addition, the values were average data during steady state or all operation in each stage?
5. Why the anaerobic step-feeding mode effected on decreasing SRT (as in Table 3) which caused the loss of nitrifying bacteria, PAO and finally the decrease in N and P removals efficiencies. The scientific reason should be explained.
6. There are some mistakes in spelling and figure number (Line 66, 299, 334, 561)
Author Response
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Author Response File: Author Response.docx