Effect of Alfalfa-Derived Biochar on Anaerobic Digestion of Dairy Manure

Round 1

Reviewer 1 Report

The present study investigated the effects of alfalfa-derived biochar addition on anaerobic digestion of dairy manure. Manuscript was well organized and written. I think it needs some revisions.

-L111: '.' was missing in the manuscript.

-L128: AF-BC

-L140: 0-10 g/L

-L174-176: Maybe a table that presents the results of previous study was better for comparison?

-Fig. 2 was blurred to the readers.

-The pyrolysis temperature was 350°C in this study, why did you choose this temperature? As you stated in the manuscript, the toxicity of BCs was higher at low pyrolysis temperature (300-400°C).

-Pay attention to the tense in the 'Results and discussion' section.

Author Response

I attach my response as a file.

Author Response File: Author Response.docx

Reviewer 2 Report

General comments

-This manuscript, by authors, studied “Effect of alfalfa-derived biochar on anaerobic digestion of dairy manure”.

Overall, the topic is of interest to Agronomy, readers. However, the following are the specific comments on the article concerns.

Specific Comments and Suggestions

-Abstract

-The first methodology, needs to be clear or improved in a better way for treatments, then, show the results of your study.

- “COD removal”. Please mention the full form first, then its abbreviation.  

-And check again for the overall manuscript again.

-Introduction

-Please mention full form first, then its abbreviation “soluble COD (SCOD)”.

- “volatile fatty acids (VFAs)”, Already mentioned in the introduction section, is better to use just an abbreviation.

-Better to explain more importance of grass alfalfa (AF), worldwide.

-Materials and Methods

-Please add pictures of your experimental setup.

-What is your baseline for comparison?

- Please clear your experimental duration. About a month? 40 days?

Add details for comparison.

• Analysis based on ALPHA standard? No other analysis or significant differences as mentioned in results?

 -Results and Discussion

-“3.1. Effects of AF-BC addition on methane and biogas production

3.1. Potential roles of AF-BC in AD 247

3.2.1. COD, ammonia, and phosphate”.

-Please check again sub-sections numbering again.

-Figure 2 need to revise and make it more clear or increase its resolution.

-“It was found that addition of the BC at high loading rates caused the significant accumulation of propionic acid which could inhibit methane production.” Reference, please?

-In figure 3, statistical analysis is not mentioned. Check for other figures as well.

- Figure 4 also needs to revise and make it more clear or increase its resolution.

-Conclusions

- “The AD of dairy manure with the addition of AF-BC at 1-5 g/L showed the significant 376 enhancement of biogas and methane production compared to the control.”

-Significant differences on which basis? Not specific analysis or just on model-based?

-Please add a little about the significance of your study about its application and specific approach.

Author Response

I attach my response as a file.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors did good efforts to revise the manuscript.