This comment is identical to that submitted earlier as "community comment"

This is an interesting study that examines a geophysical (ERT) investigation of soil aquifer treatment (SAT). It is well-written, and most of the discussion, especially that related to the core data (electrical), is well-supported and thoroughly discussed. Surprisingly, very little research followed the pioneering work of Haaken et al. Perhaps even more surprising is that the authors also almost ignore it (and even cite it in the wrong context). This is actually my main criticism of this work - it ignores much of the relevant SAT literature, especially the content from the SHAFDAN site in Israel, which is by far the world's largest and has been in operation for over three decades. This criticism by no means suggests that this work is not of value, but it certainly lacks - not only in the introduction part of the manuscript, but perhaps mostly in the discussion

Below are several specific comments

1. While not the core of this study, it is about time that researchers stop claiming that adsorption is a key element in SAT. A simple mass balance would show that all the adsorption capacity is used at a relatively early stage of the SAT facility life, and additional adsorption is possible only if there exists a degradation process that ‘empties’ adsorption sites
2. L68: Biofilms are not the critical element. Microbes are. Biofilms are the environment that helps microbes perform their functions
3. Apparently, the authors did not read Haaken et al. thoroughly…
4. Interestingly, the authors practically ignore the vast body of literature that comes from the Israeli SAT experience – the largest of its kind that has operated for about 30 years, and is documented quite well in the literature
5. Pulse (it is fine to use a short version, but be consistent and use short or full versions synchronized)
6. ~L145. Isn’t the difference in environmental conditions (temperature) a concern?
7. Section 2.4. Any petrophysical model to relate resistivity with water content?
8. Is a quarter of a second enough to get charge stability for the reactive layer?
9. 2-3. These plots are helpful, but zooming in to show a single representative day or two at different periods would be much more interesting
10. Figures 5-7 are nice, but difficult to analyze. The authors are encouraged to use some integrative type of analysis that would smooth the noise
11. 5through 7.
12. L423-426. This is not much more than speculation. Any evidence?
13. This is an interesting idea, but it requires much better support. Resistivity ‘hot-spots’ indicate water content. From here to biochemical hot-spots, the distance is quite far. At best, it indicates the formation of biofilm, but there are so many things that can trigger biofilm formation (some of which are related to microbial stress, not to microbial prosperity
14. L456 and on. Well, understanding that oxygen monitoring is useful is interesting, but given that this is the only thing that was monitored, it puts it in a different light. What about ORP (just an example) – won’t that be equally supportive? While I do not argue, it isn't easy to conclude here
15. The use of biological materials to enhance biochemical activity is not new, but interesting in the context of ERT. Nevertheless, this practice needs to be discussed in terms of long-term activity. It is not trivial to refresh such a layer after its functionality diminishes

This paper applies a comprehensive set of techniques to monitor the performance of a pilot‑scale sustainable water‑treatment system, characterised by low energy demand and reduced chemical consumption compared with conventional alternatives. It provides a clear, detailed, and concise description of the methodology and pilot‑plant setup, along with a thorough analysis of the results, effectively leveraging the information obtained from each monitored variable. Moreover, I consider that the study represents a clearly written step forward in understanding how the choice of infiltration media and the recharge strategy—pulsed versus continuous—affect system behaviour, water content, and biofilm development within the unsaturated zone. The work also offers a solid and well‑framed discussion of the results, integrating recent and relevant literature to contextualise the findings and highlight their contribution to current knowledge.

Please find below minor comments to improve the reading and understanding of your manuscript:

Line 202: Please consider changing “Supporting Information” to "Supplementary Material”

Line 228: Please remove “..” at the end of the line.

Line 241: I would recommend reorganising the figures in the Supplementary Material so that their numbering follows the order in which they are quoted in the manuscript. Currently, Figures SI.10 and SI.11 appear before SI.8 and SI.9 in the text.

Line 298: Please double-check “ER”. It seems this should be “ERT”.

Line 364: Change “Figure 5(“ by “Figure 5 (“

Line 378: Please consider adding the method for determining the permeability value of 10 m/day. I consider it would be beneficial for the readers to have this information.

Supplementary material:

SI.1. Consider moving the explanation of Figure SI. 3 before its first mention in the text.

SI 2.1. Double checked the use of “v” in “Aquacheck prove. The Aquacheck probe