Constructed Wetlands Using Treated Membrane Concentrate for Coastal Wetland Restoration and the Renewal of Multiple Ecosystem Services

Round 1

Reviewer 1 Report

 

This paper intends to present the performance of CWs treating ROC and the impact of treated water for restoration of a natural wetland in two pilot studies. This study is a practical topic with potential. It, however, had three major drawbacks. First, this study does not provide any data for coastal wetland restoration and renewal of multiple ecosystem services as described in its title. Second, the research design and methods, such as test periods, sampling frequency, water chemistry analyses, and toxicity tests, are not adequately described. Third, the result section provides an incomplete presentation of data. 

The method and result sections need to be completely revised because of lacking details. The differences between this MS and 'Natural Treatment of High-Strength Reverse Osmosis Concentrate by Constructed Wetlands for Reclaimed Water Use'(NTH) need to be addressed. The authors can follow the descriptions and presentations in the NTH paper to describe methods and results in the current MS.

 

Author Response

Thanks for commenting on our manuscript. After addressing comments in the revised manuscript, we feel that it helped quality of our paper.

A brief description on the restoration and renewal of multiple ecosystem services using the reclaimed water generated from the constructed wetland treatment has been added in the revised text.

The research design and methods have been revised as commented. Thanks.

The result section has been revised.

The differences between two studies have also been described.

Reviewer 2 Report

Dear Authors,

I am positive about the overall manuscript, but I do have a few questions about the methodology. Perhaps they will inspire you to expand your work

1 could you elaborate on the characterization of raw water? - characteristics of basic parameters, depth of the shot.

2 I don't think it sounded good at work - how many samples were taken? at what intervals? are the values shown, for example, in Figure 10, the values from one independent measurement?

3 The research was carried out on a pilot scale, in a fairly wide temperature range due to local conditions. Taking into account the influence of temperatures on the purification effect obtained, were the samples for analysis taken at fixed times?

4 It would also be worth expanding the information on the membrane itself and its properties, retention capacity, cut-off, characteristics of retained compounds.

Author Response

Thanks for commenting on our manuscript. Please see our responses to the comments below.

1. Characteristics of basic parameters of the influent water to CW based on the field data and lab data have been provided in the revised manuscript.
2. The number of samples and the frequency of sampling have been provided in the revised manuscript.
3. In general, it is yes the sampling was done between certain time of the day during sampling over the time. The temperature profile at the pilot study location has been provided in the revised manuscript.
4. A new section on the reverse osmosis method in the pilot study has been provided in the revised manuscript. This discussion is more aligned towards the influent water quality for CWs related to the focus of this study.

Reviewer 3 Report

The manuscript is within the topic of interest of the readers of land Journal. The need of treating concentrates is real and many studies are being carried out on the topic. However the state of the art do not show clearly the research need based on previous  constructed wetlands studies for compleax wastewaters. It seems like one more study which represents a marginal novelty.

Data should be further comment on the potential accumulation of metals and emerging contaminnats at long term even if the treated water is at the moment below the limits.

Conclussions should be more elaborate to show the progress beyond the state of the art.

A better description of the pilots is needed to assure the replication of the study for a different researcher.

Author Response

Thanks for commenting on our manuscript. Please see our responses to the comments below.

This study is particularly important since this study focuses on the CW’s removal efficiency of high strength RO concentrate for reclaimed water use which is not a common topic in the literature. Most of the studies in the literature are on the CW treatment of secondary effluent from a wastewater treatment plant. The difference between ROC and secondary effluent of a wastewater treatment plant has been presented in Figure 12 and Table 2 of the revised manuscript. It was a challenge and very much unknown to treat ROCs using CW.

The issue of accumulation of contaminants has been provided in the discussion section.

Conclusions have been revised.

Details of the pilot study components, methods and results have been added in the revised manuscript so that a researcher can follow this study and replicate, if needed.

Round 2

Reviewer 3 Report

Authors have improved the manucript following the recomendations.

However the experiments have been carried out in the period 2003 -2006, what is the reason for such a delay in the publication of the results?

There are some further data? It will be very strange to publish data more than 10 years old.

Author Response

This study, design and construction of the Oxnard constructed wetland projects spanned a period from 2004 through 2012, with an additional decade for operation. In our experience, this is not unusual for a constructed wetland project to require a decade of design and construction and another decade of operation before results are considered suitable for publication. The process of learning from pilot projects and applying those results to the ultimate design is iterative and lengthy. This paper primarily discusses the pilot wetland aspects of the project but includes the application of the results toward the design of the demonstration project (Figures 10 and 11).

Our previous paper (Chakraborti, R.K.; Bays, J., Natural Treatment of High- Strength Reverse Osmosis Concentrate by Constructed Wetlands for Reclaimed Water Use, Water, 2020. 12(1), 158. doi.org/10.3390/w12010158) was published three years ago. Our current paper (this submittal to Land) has been prepared with an expanded focus on the use of constructed wetlands for multiple ecosystem services and includes previously unpublished data.

We believe we don’t need to make any changes to the manuscript.

Author Response File: Author Response.docx