Waste Ochre for Control of Phosphates and Sulfides in Digesters at Wastewater Treatment Plants with Enhanced Biological Phosphorus Removal
, Salar Haghighatafshar 2, Hamse Kjerstadius 3 and Jes la Cour Jansen 2,*Round 1
Reviewer 1 Report
In this manuscript authors have introduced waste ochre to reduce hydrogen sulfide in biogas production and to reduce phosphate release into sludge liquor at WWTPs with enhanced biological phosphorus removal.
The idea is novel and interesting. However, some parts of the discussion is poor and should be improved by concerning the following points.
Authors mentioned that amount of released phosphate reduce with the addition of ochre. Describe the reason for the reduction of released phosphate using suitable literatures. Use of higher of ochre cause to produce higher sludge. Give some recommendations to prevent higher sludge production. Quality of the figures are little low. If authors can improve the quality of the figures, manuscript will be more attractive.Author Response
Please see the attachment
Author Response File: 
Author Response.docx
Reviewer 2 Report
The subject of manuscript with title "Waste ochre for control of phosphates and sulfides in digesters at wastewater treatment plants with enhanced biological phoshorus removal" is very interesting.
The abstract should clearly indicates the relevance of the work and provides background knowledge focused on the topic.
Introduction
There are some references that must be updated.
What is the main aim of the study? It should be clear defined to close the section of introductory concepts.
Material and methods
The methodological design is clear.
Results and discussion
The results are presented clear, figures used to show them are adequate.
It is important to start the discussion with a paragraph that emphasizes the relevance of the study. The same concerns to conclusions.
Some detail editorial remarks:
For example in the line 30 should be 0.75mole Fe3+/mole P released;the same in line 113, 130, 148, 245, 246. In line 189 should be 320 NmLC CH4/gVS in the in the end of....., the same in line 200, 201?
Author Response
Please see the attachment
Author Response File: Author Response.docx
