Articles | Volume 26, issue 6
© Author(s) 2022. This work is distributed underthe Creative Commons Attribution 4.0 License.
Continuous monitoring of a soil aquifer treatment system's physico-chemical conditions to optimize operational performance
- Final revised paper (published on 23 Mar 2022)
- Supplement to the final revised paper
- Preprint (discussion started on 07 Oct 2021)
- Supplement to the preprint
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor |
: Report abuse
RC1: 'Comment on hess-2021-455', Anonymous Referee #1, 04 Nov 2021
- AC1: 'Reply on RC1', Tuvia Turkeltaub, 24 Dec 2021
RC2: 'Comment on hess-2021-455', Anonymous Referee #2, 12 Nov 2021
- AC2: 'Reply on RC2', Tuvia Turkeltaub, 24 Dec 2021
Peer review completion
AR: Author's response | RR: Referee report | ED: Editor decision
ED: Publish subject to revisions (further review by editor and referees) (27 Dec 2021) by Gerrit H. de Rooij
AR by Tuvia Turkeltaub on behalf of the Authors (28 Dec 2021)  Author's response Author's tracked changes Manuscript
ED: Referee Nomination & Report Request started (04 Jan 2022) by Gerrit H. de Rooij
RR by Anonymous Referee #2 (21 Jan 2022)
RR by Ofer Dahan (08 Feb 2022)
ED: Publish as is (08 Feb 2022) by Gerrit H. de Rooij
The manuscript "Continuous Monitoring of a Soil Aquifer Treatment System’s Physico-Chemical Conditions to Optimize Operational Performance" presents a study on the impact of duration of wetting and drying cycles on the treatment efficiency in a soil aquifer treatment (SAT) facility. The study includes extensive high-resolution measurements of water content, gaseous oxygen (O2), and redox (Eh) in multiple depths across the upper part of the vadose zone (<1.5) under the flooding area of a ~20 m deep unsaturated zone. Information on the variations in hydraulic, physical and oxidation conditions in the soil, combined with flow model during the wetting and drying cycles in both winter and summer were used to define optimal operation condition of the infiltration ponds. The manuscript is well written and definitely merit publication in HESS. Yet there are few issues that should be addressed prior to publication.
Description of the wetting process that follows the flooding events, as measured by the water content sensors, is described and further analyzed as development of saturation conditions in the vadose zone. Yet the data, as presented in figure 2, which is well in line with many other publications on infiltration under flooding conditions, shows that saturation is achieved only in the very shallow part of the vadose zone, in between 25 to 50 cm. Under that shallow layer the conditions are unsaturated, even though percolation continues further down, and the wetting front keeps flowing under that layers. Infiltration that is limited by shallow layer has been observed regardless the potential clogging by organic matter effluents characteristics. It has been observed even for infiltration of fresh water in uniform sandy formations.
Obviously, prevailing of unsaturated conditions immediately below the shallow saturated layer would impact dramatically the oxidation conditions as well as the analysis of the percolation conditions. The impact of the gas phase in the unsaturated layer very close to the surface, is well reflected through the O2 and Eh sensors at 50-100 cm, as can be observed in figures 4 and 6. Obviously these are the most important parameter for efficient water treatment. However in the is manuscript, most of the analysis that refers to the treatment efficiency refers mainly to 25 cm which is in the very shallow saturated part (e.g. information presented in figure 7 8 and 9), ignoring the hydraulic and oxidizing conditions under that layer. Accordingly, I believe that the authored should elaborate on the potential impact of the unsaturated conditions that prevail vary close to the shallow saturated part, on both the infiltration and treatment conditions.
One more aspect which is rather technical refers to the structure of figure 9. It is a very strange presentation where O2 concentration is presented Vs depth in multiple times, while the depth is constant and the time is variable. The data should be presented as O2 concentration Vs time in single or multiple depths.