Significance of Pretreatment in Enhancing the Performance of Dry Anaerobic Digestion of Food Waste: An Insight on Full Scale Implementation Strategy with Theoretical Analogy
Round 1
Reviewer 1 Report
In the reviewed article, the impact of pretreatment under different operating conditions on the physico-chemical characteristics and the morphological changes in the food waste is explained. A comparative assessment of biogas production profile and organic matter removal rates achieved from pre-treated food waste was compared to that of untreated food waste to investigate the effect of pre-treatment on the input energy required and the net energy generation.
The experiments were carefully planned and their description does not raise any objections.
In rich European countries, increased pressure hygienisation is sometimes recommended and, as shown in the reviewed article, such a process is beneficial. However, it cannot be denied that it is highly energy-intensive.
Unfortunately, all drawings require attention and corrections
The authors should correct kg / cm2 to kg / cm2 and CH4 to CH4
Fig 9. X axis description too long, illegible
Fig. 11 -Please analyze carefully. The best result is for Untreated FW (dark blue colour). Duplicate data were entered for the Pre-treated food waste at the pressure of 0.5 kg / cm2 (yellow colour). I suggest using other expressive colours.
Author Response
Reviewer #1:
In the reviewed article, the impact of pretreatment under different operating conditions on the physico-chemical characteristics and the morphological changes in the food waste is explained. A comparative assessment of biogas production profile and organic matter removal rates achieved from pre-treated food waste was compared to that of untreated food waste to investigate the effect of pre-treatment on the input energy required and the net energy generation.
The experiments were carefully planned and their description does not raise any objections. In rich European countries, increased pressure hygienisation is sometimes recommended and, as shown in the reviewed article, such a process is beneficial. However, it cannot be denied that it is highly energy-intensive.
- Unfortunately, all drawings require attention and corrections
The authors should correct kg / cm2 to kg / cm2 and CH4 to CH4
Response: The suggested changed has been incorporated in the revised manuscript (Fig.6-line 417; Fig.5-line 376; Fig.4-line 352; Fig.3-line 326; Fig.2-line 305; Fig.1-line 273; Fig.9-line 488; Fig.10-line 531; Fig.11-line 584).
- Fig 9. X axis description too long, illegible
Response: The X-axis in Fig.9 has been changed to make it clearly visible (line 488).
- 11 -Please analyze carefully. The best result is for Untreated FW (dark blue colour). Duplicate data were entered for the Pre-treated food waste at the pressure of 0.5 kg / cm2(yellow colour). I suggest using other expressive colours.
Response: Duplication has been deleted. The suggested change by the reviewer has been incorporated in the revised manuscript (line 584).
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The pre-treatment process in the dry Dry-AD is thoroughly investigated, and the paper is considered to be of high value.
I would like to comment on the following points
1) In Figure 9, the horizontal axis "after at" is not visible. Please revise it.
2) The vertical axis in Figure 10 should be in the form of "kWh/unit".Please enter the appropriate unit.This comment is not a request for modification of the figure, but only a recommendation for modification of the unit.
3) What do you mean by "Implications at full scale"? In such a process, it is not always possible to apply the experimental results to the full scale as they are due to variations in the entry conditions and scale up factors. In the case of a full-scale plant, information on the scale of processing is also required. If you have difficulty in addressing these points, I recommend changing the wording to "Implications at full scale".
Author Response
Reviewer #2:
The pretreatment process in the dry Dry-AD is thoroughly investigated, and the paper is considered to be of high value.
I would like to comment on the following points
- In Figure 9, the horizontal axis "after at" is not visible. Please revise it.
Response: The change has been made in Fig.9 (line 488) as per the reviewer’s suggestion.
- The vertical axis in Figure 10 should be in the form of "kWh/unit". Please enter the appropriate unit. This comment is not a request for modification of the figure, but only a recommendation for modification of the unit.
Response: Appropriate unit in kWh/(m3 of methane) in Fig. 10 (line 531) is added as per the suggestion given by the reviewer.
- What do you mean by "Implications at full scale"? In such a process, it is not always possible to apply the experimental results to the full scale as they are due to variations in the entry conditions and scale up factors. In the case of a full-scale plant, information on the scale of processing is also required. If you have difficulty in addressing these points, I recommend changing the wording to "Implications at full scale".
Response: The subheading has been changed from “Implications at full scale” to “Insights on implications at full scale based on laboratory investigations” in Line 561.
Author Response File: Author Response.pdf
