Realizing the Circular Economy for Sanitation: Assessing Enabling Conditions and Barriers to the Commercialization of Human Excreta Derived Fertilizer in Haiti and Kenya

Round 1

Reviewer 1 Report

The topic of this manuscript is highly relevant in the frame of recycling urban waste for the use in agricultural production systems. The case study aims to identify the enabling conditions for the success and challenges of the two companies from Haiti and Kenya. The main challenges identified by the study are a lack of fertilizer regulations and the profitability of selling human waste derived fertilizers. The two case studies provide valuable information on current limitations for the use of recycled fertilizers by farmers in low- to mid-income countries.

The study demonstrates very clearly the missing awareness for the need and the potential of recycling urban/human waste which is a major hurdle for integrating human waste derived fertilizers into agriculture crop production systems. However, the main limitation of the manuscript is that the information provided is limited and that the conclusions reflect largely the view of the companies by focusing mainly on the financial challenges but not on the missing opportunities. It is therefore not convincing that the lack of regulations and subsidies are the only/main barriers to the commercialization of the products. The study should provide more information on the market environment and add some comments on the enabling conditions for the success of the two companies as well. For example, it remains unclear whether the companies are able to sell all the waste they collect. The target customers of the companies should be critically discussed as well as the selection of the stakeholders for the survey. It is doubtful to consider vegetable growers as primary customers for human waste derived fertilizers considering the high risk associated with food safety and current fertilizer regulations in Europe or elsewhere. Further, the study does not address clearly the missing opportunities and potentials of the companies such as other market areas than vegetables or organic certified producers, type and form of products being sold and the efficiency of product transportation. ‘Green tax’, subsidies and regulations represents only one aspect of the current low use of humane waste derived fertilizers in the agricultural sector. In general, the authors should better explain which information they obtained from the survey and critically discuss their findings in order to be more convincing.

I come to the conclusion, that the paper requires revision. The attached comments might be helpful when revising the manuscript.

Comments for author File: Comments.pdf

Author Response

Many thanks to the reviewer for their detailed comments which have enabled us to improve the manuscript.   Our response is found in the attached document.

Author Response File: Author Response.docx

Reviewer 2 Report

Research on this topic is needed and it will encourage other researchers to conduct research on this topic. 

Author Response

We are glad that the reviewer enjoyed the paper.

Reviewer 3 Report

Thank you for the chance to read this paper. I think this is a nicely straight-forward paper, and gives some good insight into these barriers you describe. 

There are only some issues with the manuscript as written, largely, be sure to take another pass through the document and be consistent with feces vs faeces usage, as well as a typo in line 135. 

Author Response

The paper has been rechecked to ensure that the word "feces" is used throughout, and thr typos on line 135 has been corrected.

Round 2

Reviewer 1 Report

The authors have revised the manuscript and considered most of the comments.