Modelling Phosphorus Sorption Kinetics and the Longevity of Reactive Filter Materials Used for On-Site Wastewater Treatment

Round 1

Reviewer 1 Report

The present paper concerns the development of a mechanistic model to simulate phosphorus sorption kinetics and to predict the longevity of three reactive filter media.

The paper reveals that a good amount of numerical work was undertaken. Additionally, the simulations were compared with previously obtained experimental data and are consistent with the conclusions. The manuscript is well written and organized.

However, the authors ought to comment on the feasibility and sustainability of using such reactive man-made materials as filter media for wastewater treatment concerning two main issues: (i) the production of these materials is associated with a high energy consumption; (ii) the use of these materials cause the increase in the water pH, which can be higher than the legal discharge limits (line 272).

The residence times presented in the line 108 should be checked as they do not seem to be in the correct order according to the porosities referred in line 88.

Please verify the porosity of Filtralite P in lines 87 and 194.

Author Response

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Reviewer 2 Report

The article gives interesting information on the longevity of three different reactive filter materials for improving phosphorous removal from wastewater and indicated best performance of Polonite. Overall, this article is of practical importance for onsite wastewater treatment system. I recommend its publication after some minor revisions.

1)       Line 88-89! Why different pH was selected for characterizing different RFM materials.

2)      Conclusion should be precise and give brief information of the main findings.

Author Response

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Author Response File: Author Response.docx