Evaluation of a Wet Acid Scrubber and Dry Filter Abatement Technologies in Pig Barns by Dynamic Olfactometry
Round 1
Reviewer 1 Report
The publication may be a very valuable research material, but it is difficult to evaluate the presented test results due to the lack of details regarding the method, preparation (e.g. dilution) of sampling, repeatability and parameters of the collected gases, which in the case of odorogenic gases is very important and constitutes o the final result in terms of the odor concentration values. In addition, there are no details on the selection of probants, determination of the test time in relation to the performed odour concetrations measurements. These comments were marked in the text in the commentary mode and their completion determines the further evaluation of the work.
Comments for author File: 
Comments.pdf
Author Response
Dear Reviewer,
in attach the file "Reviewer 1_response.docx" with the point-by-point response.
Author Response File: Author Response.pdf
Reviewer 2 Report
The article touches important issue on odours reduction options and technologies from farms.
The introduction of article clearly describes the aim of study and possible measures for the reduction and mitigation of odours emissions.
The materials and methods part of the article must be improved.
Line 86 - 97
To compare the odours abatement efficiency of two different systems (DF and WAS) in the buildings with natural ventilation, following data are missing:
- Characteristics of animal housing (e.g. inner volume of the barns, number of windows, doors, were they closed or how many of them were opened during the sample collection, etc.);
- Environmental conditions inside the barns and outdoors during the sample collection sessions (temperature, humidity and air velocity (drafts));
- Position of all three barn buildings regarding to prevailing wind direction and each other;
- Wind direction during sampling sessions;
Line 98 – 114
More details must be given about the application of abatement technologies!
- What type of sorbent is contained inside the dry filter (charcoal, silicagel, other materials)? Is it suitable for amines, sulphuric and ammonia compounds, which were mentioned as dominant odorants on swine farms (line 41)?
- It is necessary to describe how air circulation is ensured through filtering material (for DF and for WAS), aspirating mechanically or by some other method? If a mechanical pump is used, what is the pumping capacity and is the same amount of air cleared through the two comparable systems over the same period?
- What is the exact location of dry filter in the room? Is it in the middle of the room, or next to the walls, is it at the floor level or elevated above it?
There is no any doubt about the suitability of odometry to assess the intensity of odors, however, in order to evaluate and compare the effectiveness of the two different filtering systems, it is necessary to provide the best standardized conditions possible. If the experiment is carried out outside a standardized laboratory environment, the possible causes of errors in the results should be evaluated and the methodology of the experiment described in the most precise and detailed way. In this particular experiment, due to the small number of air samples taken, we should account for different properties of farm buildings (area, orientation, etc.).
Line 155
How many results (with all replicates) of one sample were used for calculation of standard deviation?
Line 157
Number of samples taken for each session is missing in the columns “Wet acid scrubber”, “Dry filter” and “Control”. Especially, if you have written (line 153), that only 84 from 100 samples were valid.
Line 170
The Figure 1 represents the same data that already are presented in the Table 1. It is not necessary in this case. It will be more useful if error bars and analysis of statistical significance are added. There is a large difference in the odour concentration levels between sessions, therefore other scaling should be used.
Author Response
Dear Reviewer,
in attach the file "Reviewer 2_response.docx" with the point-by-point response.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors of the publication responded to the indicated issues and supplemented the text. I advise you to proceed with the publication of the article.
