Sustainability in Aquatic Ecosystem Restoration: Combining Classical and Remote Sensing Methods for Effective Water Quality Management

Round 1

Reviewer 1 Report

The authors analyzed the impact of satellite remote sensing on reservoirs and calculuated the distribution of water quality parameters such as chlorophyll, as evidence of two acts of remediation by adding microbial agents to improve water quality. The research scope has lasted for nearly 10 years. However, there are some problems in the data analysis and conclusion.

1) The composition of microbial agents and the mechanism of action in balancing biological systems are not provided. It is impossible to determine whether EM may produce an effect from theoretical thinking.

2) Location and representativeness of sampling points for water quality testing data in 2013 are missing. Why the in-situ water quality data had not covered the time-range of the study? It's the direct evidence for water quality improving.

3) How 5 m3 microbial agents can have long-term effects on 548000 m3 of water? There is a lack of necessary calculation and literature support. 

4) The lack of correlation between water quality data and satellite data, making it difficult to verify the calculation and support the conclusion.

5) There are many reasons for the improvement of water quality in a reservoir. In the paper, there is a lack of solid evidence for the effectiveness of microbial agents, which raises my doubts on the conclusion.

Author Response

Dear Reviewer,

Thank you very much for your constructive feedback on our manuscript on the research on effect of microbiological restoration of the Siemiatycze Lakes. The manuscript has been supplemented and restructured in accordance with the reviewers' suggestions. The article was supplemented with a clearly formulated research purpose. The title has also been changed to more accurately reflect the aim and scope of our research.

• The composition of microbial agents and the mechanism of action in balancing biological systems are not provided. It is impossible to determine whether EM may produce an effect from theoretical thinking.

As suggested, based on literature data, the manuscript was supplemented with a description of the mechanisms of action and composition of biopreparations. However, the mechanisms of EM action have not been the subject of performed studies. The objective of this study was to evaluate the alterations in the water quality of the Siemiatycze Lakes following two bioremediation treatment cycles utilizing biopreparations enriched with Effective Microorganisms. This research analyzed a set of water quality parameters—including dissolved oxygen, transparency, chlorophyll-a, pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total phosphorus, total nitrogen, and suspended matter (SM)—across eleven designated sampling locations. Additionally, the study employed remote sensing techniques, leveraging Sentinel-2 satellite imagery and the Maximum Chlorophyll Index (MCI), to detect and quantify algal blooms, with a particular focus on elevated chlorophyll-a concentrations.

• Location and representativeness of sampling points for water quality testing data in 2013 are missing. Why the in-situ water quality data had not covered the time-range of the study? It's the direct evidence for water quality improving.

Thank you for your comment. The location of the sampling points is shown in the modified Figure 1. During the first series of bioremediation treatments in 2013-2014, water parameter measurements were performed 4 times (07.2013; 08.2013; 11.2013; 05.2014). Water parameter analyses were conducted four times each year during the second series of bioremediation treatments in 2016-2017 (05.2016; 07.2016; 10.2016; 11.2016; 04.2017; 05.2017; 07.2017; 10.2017; 11.2017; 04.2018). We have updated the "Methodology" section with the above information.

• How 5 m3 microbial agents can have long-term effects on 548000 m3 of water? There is a lack of necessary calculation and literature support. 

The doses were selected by the company contracted by the city to carry out the reclamation work. The exact composition and volume were determined on the basis of laboratory tests carried out individually for the water in the reclaimed reservoir. Nevertheless, neither the selection of doses nor the performance of reclamation was performed by the authors of the manuscript. The method of carrying out the reclamation process was also not the subject and aim of the conducted research. The article was supplemented with a clearly formulated research purpose. The title has also been changed to more accurately reflect the aim and scope of our research.

• The lack of correlation between water quality data and satellite data, making it difficult to verify the calculation and support the conclusion.

The results obtained from the water and satellite image analyses are described in separate subsections. The reduction in chlorophyll a concentrations observed in 2016 (Fig. 16) and 2017 (fig.17) (compared to 2015) corresponds with the results of the water test where reductions in total phosphorus and total nitrogen concentrations were shown (Fig. 7). The key issues from both parts of studies are brought together in a rewritten Conclusions chapter.

• There are many reasons for the improvement of water quality in a reservoir. In the paper, there is a lack of solid evidence for the effectiveness of microbial agents, which raises my doubts on the conclusion.

For years before the restoration treatments, the water in the reservoirs was in poor quality. Blooms were regularly observed. After the first series of reclamation treatments (2013-2014), analyses of water parameters and the visual observations of the effects were made. Till 2016, a renewed deterioration of the water quality in the reservoir was observed. Therefore, the reclamation process with biopreparations was performed again. In our study we indicated that improvement in the water quality parameters was observed after microbiological remediation processes were carried out. We agree that this is not clear evidence for the effectiveness of microbial agents in the Siemiatycze Lakes. In the revised manuscript, we also indicated the purpose of our research: evaluation of the changes in the water quality of the Siemiatycze Lakes following two bioremediation treatment cycles utilizing biopreparations enriched with Effective Microorganisms. Therefore, we have reworded also the conclusions.

We are committed to addressing these points and believe that these modifications will significantly enhance the clarity of our manuscript. Your feedback is invaluable in helping us improve the quality of our work, and we thank you once again for your thorough review and constructive suggestions.

Reviewer 2 Report

This manuscript is “The application of microbiological methods in re degradation of polluted water reservoir: Lake Siemiatczyce case study”. Some detailed comments are as follows:

(1) The title is about microorganisms, but there is no analysis or discussion on the changes in microorganisms in the manuscript. Therefore, I suggest modifying the title.

(2) Abstract: The problem that needs to be addressed in this manuscript is unclear.

(3) Abstract: The abstract of the manuscript lacks disclosure of relevant new mechanisms.

(4) Introduction: This manuscript lacks a clear research objective.

(5) Materials and Methods: The importance of the research area was not clearly explained by the author.

(6) Discussion: This is only a limited discussion.

(7) Conclusions: The conclusions are only the research result, and the important innovative value of this manuscript needs to be reflected.

(8) The format of Table 1-11 needs to meet the requirements of the journal, and Table 2, 4 and 11 should avoid being distributed on page 2.

(9) A proof reading by a native English speaker should be carefully conducted to improve both language and organization quality.

The English language of this manuscript needs improvement.

Author Response

Dear Reviewer,

Thank you very much for your constructive feedback on our manuscript on the research on effect of microbiological restoration of the Siemiatycze Lakes. The manuscript has been supplemented and restructured in accordance with the reviewers' suggestions.

(1) The title is about microorganisms, but there is no analysis or discussion on the changes in microorganisms in the manuscript. Therefore, I suggest modifying the title.

Thank you for that important comment. The title has been changed to more accurately reflect the aim and scope of our research: “Sustainability in Aquatic Ecosystem Restoration: Combining Classical and Remote Sensing Methods for Effective Water Quality Management”

(2) Abstract: The problem that needs to be addressed in this manuscript is unclear. (3) Abstract: The abstract of the manuscript lacks disclosure of relevant new mechanisms.

The abstract has been rewritten and includes the purpose and scope of the research conducted as well as summary conclusions of the study.

(4) Introduction: This manuscript lacks a clear research objective.

The article was supplemented with a clearly formulated research purpose. The objective of this study was to evaluate the alterations in the water quality of the Siemiatycze Lakes following two bioremediation treatment cycles utilizing biopreparations enriched with Effective Microorganisms. This research analyzed a set of water quality parameters—including dissolved oxygen, transparency, chlorophyll-a, pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total phosphorus, total nitrogen, and suspended matter (SM)—across eleven designated sampling locations. Additionally, the study employed remote sensing techniques, leveraging Sentinel-2 satellite imagery and the Maximum Chlorophyll Index (MCI), to detect and quantify algal blooms, with a particular focus on elevated chlorophyll-a concentrations.

(5) Materials and Methods: The importance of the research area was not clearly explained by the author.

The chapter has been restructured and supplemented in accordance with the defined research objective and the revised title of the manuscript.

(6) Discussion: This is only a limited discussion.

The chapter has been restructured and supplemented. Based on literature data we have completed the manuscript.

(7) Conclusions: The conclusions are only the research result, and the important innovative value of this manuscript needs to be reflected.

The conclusions have been revised and numbered with bullet points. The key conclusions from water analyses and satellite image studies are brought together in a rewritten Conclusions chapter.

(8) The format of Table 1-11 needs to meet the requirements of the journal, and Table 2, 4 and 11 should avoid being distributed on page 2.

The tables have been adjusted to the requirements of the journal.

(9) A proof reading by a native English speaker should be carefully conducted to improve both language and organization quality.

A proof reading by a native English speaker was performed.

We are committed to addressing these points and believe that these modifications will significantly enhance the clarity and effectiveness of our visual representations in the manuscript. Your feedback is invaluable in helping us improve the quality of our work, and we thank you once again for your thorough review and constructive suggestions.

Reviewer 3 Report

The research presented in the article contributes to the development of a promising method for improving the water quality of lakes and reservoirs using microbiological restoration of ecosystems and proves the effectiveness of the described methodology on specific water bodies. All stages of the work were completed quite correctly; there are comments only on the figures. The names of the states on the left side of Figure 1 must be given in English. It is advisable to replace the right part of Figure 1 with Figure 2a with captions of the studied reservoirs in Siemiatycze, and remove Figure 2 as redundant. In Figure 7, leave % on the Y axis only at the top value (100%) and add a label to the X axis.

English is good.

Author Response

Dear Reviewer,

Thank you very much for your constructive feedback on our manuscript and the positive appraisal of our work on the microbiological restoration of aquatic ecosystems. We are grateful for your recognition of the significance of our research and its contribution to advancing methodologies for improving water quality in lakes and reservoirs.

Author Response File: Author Response.docx

Reviewer 4 Report

This paper has the potential to be accepted. There are only a few minor revisions that need to be done before the paper can be published. The following are the comments to be considered:

1. Include a detailed discussion on how and why you were able to achieve better results in comparison to state-of-the-art techniques or already reported in the literature.

2. "Two bioremediation treatments were conducted in 2013 and 2014,  commencing from the start of June". The study was conducted a long time ago, so why is it being sent too late for publication?

3. Cite the following article related to the removal of various micropollutants present in dam water and wastewater: "Synthesis of PAN-nanofibers for the separation of aqueous pollutants and performance of the net-zero energy water treatment plant" (doi: 10.5004/dwt.2020.26064).

4. The conclusion should be numbered with bullet points.

Author Response

Dear Reviewer,

We sincerely appreciate your comprehensive and constructive review of our manuscript. Your recognition of the potential of our research is greatly encouraging.

1. Include a detailed discussion on how and why you were able to achieve better results in comparison to state-of-the-art techniques or already reported in the literature.

Based on literature data we have completed the manuscript. Additionally, the operation of EM was described in the paper.

2. "Two bioremediation treatments were conducted in 2013 and 2014,  commencing from the start of June". The study was conducted a long time ago, so why is it being sent too late for publication?

The revitalisation of Siemiatycze Lakes was carried out twice. The first series of bioremediation treatments were performed in 2013 and 2014, starting in early June. Further revitalisation treatments were undertaken in 2016 and 2017. The analysis of satellite data from the Sentinel-2 mission for the Siemiatycze Lakes includes the time period up to 2019.

3. Cite the following article related to the removal of various micropollutants present in dam water and wastewater: "Synthesis of PAN-nanofibers for the separation of aqueous pollutants and performance of the net-zero energy water treatment plant" (doi: 10.5004/dwt.2020.26064).

Thank you for suggesting an interesting article. We have used it in our paper.

4. The conclusion should be numbered with bullet points.

The conclusions have been revised and numbered.

We are committed to addressing these points and believe that these modifications will significantly enhance the clarity and effectiveness of our visual representations in the manuscript. Your feedback is invaluable in helping us improve the quality of our work, and we thank you once again for your thorough review and constructive suggestions.

Reviewer 5 Report

Dear Authors, 

The manuscript submitted for review addresses essential issues related to the non-invasive method of microbiological treatment of water bodies. The Authors show, based on satellite imagery telemetry studies, a significant improvement in selected water parameters. The applied methodology gives very promising results regarding the return to the proper trophic status of water bodies. The manuscript submitted for review is well read. The test is understandable, despite the use of sometimes overly sophisticated words. The substantive background of the study is adequately presented with appropriate annotations of the literature. My comments relate to several issues.

1. Throughout the text, there is unfortunately no chronology of events. In general, there are many inaccuracies about the dates on which the measurements were taken. In one place, one reads that the revitalisation occurred in 2016 and 2017 in several other places, while in a few others, one reads that there were actually two microbiological cleaning sessions, once in 2013 and 2014 and then again around 2018. Furthermore, in Section 2.1.3 we have a clear reference that the data refer only to years 2013 and 2014. In summary, we have a message about bioremediation twice. Hence, it would be worthwhile for the authors to carefully follow their own text in order to catch inconsistencies.

2. In the abstract, there is a clear mention that the proposed method of treating water bodies had a positive impact on fish populations. In the rest of the manuscript, there is no direct research to support this claim. This does not mean that this was not the case, it is just a matter of writing about what was studied and shown in graphs or figures.

3. In many places, it is not precisely stated what type of chlorophyll is meant. Most often the manuscript mentions chlorophyll-a. I think it is necessary to review the text and check whether the type of chlorophyll should be specified everywhere (because it is rather chlorophyll-a everywhere).

4. What is the abbreviation SM? In the text, the authors often use their own abbreviation EM for Effective Microorganism, but I do not find an explanation for SM (I guess more about it is than actually knowing).

5. In formula (1), there is no description of why specific numbers like 705, 665, 740 appear.

I hope that my comments will further improve an already good text. 

Yours sincerely,

Reviewer

Dear Authors, 

The article submitted for review reads rather well. There are no obvious grammatical or stylistic errors. Sentences are of appropriate length. There is no tendency to create multiple subordinate sentences. There is also hardly any problem with the use or lack of proper articles before nouns. The few inaccuracies (due to various reasons, e.g. grammatical or stylistic) do not result in an unreadable manuscript. Consideration could be given to replacing certain words or larger sequences of words with other words (in my opinion better fitting): 'outcomes'>'results', 'subsequent'>'following', 'conducted'>'carried out', 'involving'>'which involves', 'enhancement'>'improvement', 'across'>'in', 'which'>'that', 'like'>'such as', 'elevate'>'increase', 'fostering'>'promoting', 'aids in improving'>'helsp to improve', 'process of restoring'>'restoration of lakes', 'it's'>'it is', 'employing'>'using', 'can'>'may', 'maintainging'>'and maintain', 'Over'>'During', 'diminished'>'decreased', 'alongside'>'along with', 'fell short'>'were inadequate', 'tailored'>'customised', 'consortia'>'consortiums', 'commenced'>'began', 'zones'>'areas', 'stands'>'is', 'commencing from the start of'>'beginning in', 'assessment'>'evaluation', ''focusing'>'that focused', 'datasets'>'datasets are', 'for calculating'>'to calculate', 'encompassed'>'included', 'pollution'>'contamination',  'allowing for'>'allowing', 'Fig.'>'Figs.', ' Similar dependencies were observed by Jóżwiakowski'>'Jóżwiakowski observed similar dependencies', 'commonly'>'widely', 'catcgments'>'basins', 'sosurces'>'systems', 'enabling'>'that allow', 'prove'>'have proven'. Lines: 18, 24, 18, 19, 24, 24, 52, 55, 55, 57, 56, 59, 63, 67, 68, 73, 79, 80, 87, 105, 110, 111, 117, 119, 124, 143, 151, 170, 174, 194, 224, 236, 268, 280, 318, 340, 368, 373, 403, 441, 512.

Yours sincerely,

Reviewer

Author Response

Dear Reviewer,

We sincerely appreciate your comprehensive and constructive review of our manuscript. Your recognition of the significance of our research and the promising results it presents regarding the improvement of water body trophic statuses is greatly encouraging.

We acknowledge your comment on the readability of the manuscript and the use of sophisticated terminology. We aim to strike a balance between academic rigor and accessibility to ensure our findings are understandable to a broad audience, including those outside the immediate field of study. In light of your feedback, we undertook a careful review of the manuscript to simplify overly complex language where possible, without compromising the scientific accuracy or integrity of our work.

Your insights into the substantive background and the literature annotations are particularly valued, confirming that our research is well-grounded and contributes meaningfully to the existing body of knowledge.

We addressed the specific issues you have raised and will provide detailed responses to each point in subsequent comments.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors had responded to most of the questions and made some modifications. But there are still many problems and issues in the revied version, which need major revision:

1. The authors only provided a track version of revision. A clean version is also necessary, and important, to make the paper readable.

2. The author insists or assumes that EM is the main reason for the improvement of lake water quality. However, as I mentioned before, this conclusion lacks logical validity and data evidence. It is not allowed in scientific documents to accept statement without validation. Given that description of EM effectiveness goes against common sense and is difficult to accept.

3. The figures and tables are nightmare to readers.  Only 3 figures and 1 table are necessary for this paper. The other contents should be explained in text or included in supporting materials.E.g.,

(1) Figures 2-4 are not important and should be removed from main text,

(2) Figures 6-12 can be compiled into a large image to save space, and

(3) Figures 15-18 can be compiled into a single image.

(4) Except for Table 2 (It is better to be shown by a figure), all other tables are unnecessary in the main text.

Author Response

Dear Reviewer,

Thank you very much for your feedback. Below are responses to the review comments:

1. The authors only provided a track version of revision. A clean version is also necessary, and important, to make the paper readable.

The authors provided to the MDPI systems only a clear version, without tracking changes (both doc and pdf files). The publisher's system automatically marks changes between versions of the manuscript.

Tracking of changes in a doc file created by the publisher's system can be easily turned off in MS Word by: “Review > Track Changes. In the Track Changes drop-down list, select Off”.

2. The author insists or assumes that EM is the main reason for the improvement of lake water quality. However, as I mentioned before, this conclusion lacks logical validity and data evidence. It is not allowed in scientific documents to accept statement without validation. Given that description of EM effectiveness goes against common sense and is difficult to accept.

European Union policy emphasizes the increasing use of biological methods in restoring the environmental natural balance. The use of microorganisms for wastewater treatment and the revitalization of polluted, degraded reservoirs has become a popular method used on an increasingly large scale. Traditional chemical and mechanical remediation methods unfortunately interfere significantly with the natural environment, destroying many plant and animal communities. The scientific references cited in the manuscript (referring to both laboratory and field studies) indicate that the use of EM is an effective alternative to traditional remediation methods. As requested in a previous review, we have included in the manuscript an extensive explanation, based on scientific publications, of the composition and mechanisms of action of EM in wastewater/water treatment processes.

Since the EM method is well known to improve water quality parameters the use of EM biopreparations in the revitalization of water bodies has become an applied technology in industrial applications. ACS Holding, a biotechnological company, annually conducts the purification of 10-30 degraded water reservoirs using this method. ACS Holding has successfully conducted over 400 large and small water reservoir recultivations in Poland using EM biological method. After the application of selected biopreparations, both water and organic sediment components in the degraded reservoirs underwent positive changes, garnering recommendations from local authorities. Furthermore, scientific literature contains numerous articles highlighting the success of various forms of EM in lake and river purification projects. Scientific sources suggest that EM technology offers a holistic and sustainable solution for water quality enhancement. By harnessing the synergistic interactions among beneficial microorganisms present in EM formulations, this method can effectively degrade organic pollutants, mitigate the accumulation of harmful substances, and restore ecological balance within aquatic ecosystems. Based on the cited scientific literature and the results of the study, the authors come to the conclusion that the improvement in the parameters of the studied aquatic environment may have been the result of the carried out revitalization procedures.

3. The figures and tables are nightmare to readers.  Only 3 figures and 1 table are necessary for this paper. The other contents should be explained in text or included in supporting materials.E.g.,

Thank you for your comment. We have made modifications to the figures and tables. The text of the manuscript has become clearer. Figures showing changes in water parameters in Siemiatycze reservoirs in 2013-2014 (Figures 6, 8-14) have been compiled into two figures. Figures showing comparison of spatial distribution of chlorophyll-a concentration in the Siemiatycze reservoir (Figures 15-18) have been compiled into two figures (each per one side). Tables 3 and 5-11 have been moved to the appendix section. However, Table 1 containing main morphometric characteristics of Siemiatycze reservoirs is still included in the main text as relevant to the description of the study area. Table 4. is also left in the main text because it provides an essential overview of the methods and tools used in water quality research

Reviewer 2 Report

Although the author has made modifications to the entire content, there are still issues that need to be addressed.

(1) The format of the table needs to be modified according to the requirements of the journal.

(2) L747-749: Some reference formats were not modified as required, and the journal name was not abbreviated as required.

(3) The author needs to revise the English language throughout the entire text.

The English language of this manuscript needs improvement.

Author Response

Dear Reviewer,

Thank you very much for your time and constructive feedback on our manuscript. The manuscript has been supplemented and restructured following the reviewers' suggestions.

(1) The format of the table needs to be modified according to the requirements of the journal.

Thank you for your comment. The tables were made on the Sustainability template. Table 3 has been revised and moved to the appendix sections. In addition, tables 5-11 also have been moved to the appendix sections.

(2) L747-749: Some reference formats were not modified as required, and the journal name was not abbreviated as required.

Thank you for your comment. The title has been changed to an abbreviation as required by the journal.

(3) The author needs to revise the English language throughout the entire text.

Thank you for your comment. The English language was revised throughout the entire text.

Your feedback is invaluable in helping us improve the quality of our work, and we thank you once again for your thorough review and constructive suggestions.

Round 3

Reviewer 1 Report

1. Please contact the editor to provide a clean PDF file for reviewing.

2. The doubt about EM in this paper is about the parameters and not the principle, which the authors had not understood and explained.  As mentioned at the 1st review, the EM has too small amount of dosage (also the too small density of microbe in natural system), and the effects for once dosage lasted for too long time (several years). According to the information provided, there must be some other reasons for the water quality reclaim.  

Author Response

Dear Reviewer,

Below are the answers to your request and concerns:

1. Please contact the editor to provide a clean PDF file for reviewing.

As the review process is blind, authors are unable to directly address reviewers. Therefore, we regret but we cannot comply with your request, even if we wished to.

As a reviewer, you are probably familiar with the MDPI system - when loading a review, there is also a box where the reviewer can address the editor directly. In this field you can probably enter your request to the editor for a pdf document. However, we suggest using the function to disable the preview of changes in the MSWord file provided to reviewers by MDPI editors. This is really the simplest solution.

2. The doubt about EM in this paper is about the parameters and not the principle, which the authors had not understood and explained.  As mentioned at the 1st review, the EM has too small amount of dosage (also the too small density of microbe in natural system), and the effects for once dosage lasted for too long time (several years). According to the information provided, there must be some other reasons for the water quality reclaim.

We fully agree with the reviewer's comment. The application of EM biopreparations to water reservoirs is unable to maintain the proper concentration of microorganisms capable of actively biodegrading organic pollutants in real time. This is not a process involving activated sludge or microbiological biofilm as seen in municipal or industrial wastewater treatment plants, and water reservoirs are not recipients of extreme loads of organic pollutants. The loads present in these reservoirs are relatively stable and significantly smaller, after the elimination of major emitters, biodegradation processes involving microbial consortia can accelerate the purification process over the course of 1 - 2 years.

Moreover, the question here is not only about dosage, as we are not dealing with chemical treatment. Rather, we are monitoring reservoirs after using a biological approach with living microorganisms that have an exponential replication rate under the right conditions. In this context, we are dealing with a biological tipping point, where the cocktail of beneficial microorganisms applied promotes the rearrangement of naturally occurring beneficial microorganisms, thus promoting the natural ecosystem rehabilitation process.

Our team also specialize in municipal wastewater treatment processes, conducting research in areas such as ASM, SBR, MBBR modification processes, and publishing our findings in international journals. We understand why the reviewer disagrees with the real-time purification model with assumed EM doses (as it is not feasible and was not mentioned in our article as a biodegradation pathway).

Bioremediation with EM certainly stimulates autochthonous microorganisms, as we have demonstrated in our laboratory studies (not yet published) using aquaculture sediments, as well as in experimental systems. However, complete system purification at BOD5 loads (200 - 400) and COD (400 - 600) takes several months (2 - 3) in a 1m3 reactor with applied biopreparation doses of 1 L/m3. Preliminary microbiological studies confirm the increase in the overall number of bacteria (mainly autochthonous) and improvement in quality parameters (O2 concentrations). EM contribute to accelerating the improvement of the pollutants studied, but the introduced consortia are unable to fully eliminate pollutants without the involvement of other microbial groups. During the season, we also observe an increase in the number of EM microorganisms introduced into the reservoir water; nevertheless, the development of other autochthonous microorganisms with their participation is greater.

Perhaps the presence of nutrients and stimulants in the biomass mixtures additionally stimulates autochthonous microorganisms present in sediments and reservoir water, and their growth accelerates self-purification processes. To confirm this hypothesis, we need to conduct experiments, which we are currently planning.