Pathogen removal options: emphasizing SOLDIS for the filtrate of a GSAP Microflush toilet

Mecca, Stephen J.; Pellock, Brett J.; Bretz, R.

doi:10.2495/ws130171

Cited by 4 publications

(6 citation statements)

References 6 publications

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“…The ability of the GSAP Microflush toilet to process waste is supported by previous studies investigating temperature distribution within the digester (Mecca et al, 2017) and the use of SODIS for pathogen reduction in liquid effluent (Mecca et al, 2013b). In addition, studies of vermicomposting as a waste treatment method have demonstrated the effectiveness of this approach for mass reduction and pathogen removal (Hill and Baldwin, 2012;Soobhany et al, 2017).…”

Section: Manuscript To Be Reviewedmentioning

confidence: 80%

“…The genera and unclassified OTUs that were abundant in the untreated liquid effluent were greatly reduced or not detected in the SSF-treated effluent; however, these taxa increased in abundance in the SODIS-treated effluent. A previous study of SODIS for application with the GSAP Microflush toilet system showed significant reduction of viable E. coli over eight hours of exposure to sunlight (Mecca et al, 2013b). Given this and other studies showing the capacity of SODIS to sanitize contaminated water (Boyle et al, 2008;Caslake et al, 2004), it is possible that PeerJ reviewing PDF | (2018:09:31004:1:0:NEW 31 Oct 2018)…”

Section: Discussionmentioning

confidence: 94%

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Peer Review #1 of "Bacterial communities in the digester bed and liquid effluent of a microflush composting toilet system (v0.1)"

Murcott¹

2018

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Sustainable Aid Project developed a microflush composting toilet system to isolate and treat human waste. Solid waste is composted within a filter-digester bed via an aerobic process involving microbes and invertebrates. Liquid waste may be sanitized by solar disinfection (SODIS) or slow sand filtration (SSF). Here, we used 16S rRNA amplicon sequencing of samples from a scaled-down test version of the system to better understand the bacterial component of the toilet system. Immediately after fecal matter was deposited in the test system, the bacterial community of the filter-digester bed at the site of deposition resembled that of the human gut at both the phylum and genus level, which was expected. Genus-level analysis of filter-digester bed samples collected over the next 30 days from the site of deposition showed reduced or undetectable levels of fecalassociated taxa, with the exception of Clostridium XI, which persisted at low abundance throughout the sampling period. Starting with the sample collected on day 4, the bacterial community of the filter-digester bed at the site of deposition was dominated by bacterial taxa commonly associated with environmental sources, reflecting a major shift in bacterial community composition. These data support the toilet system's capacity for processing solid human waste. We also analyzed how SODIS and SSF sanitization methods affected the bacterial community composition of liquid effluent collected on day 15 from the test system. Untreated and treated liquid effluent samples were dominated by Proteobacteria. At the genus level, the bacterial community of the untreated effluent included taxa commonly associated with environmental sources. In the SODIS-treated effluent, these genera increased in abundance, whereas in the SSF-treated effluent, they were greatly reduced or undetectable. By analyzing OTUs that were unclassified at the genus level, we observed that SSF appears to introduce new taxa into the treated effluent, likely from the biological film of microbes and small animals that constitutes the key element of slow sand

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Section: Manuscript To Be Reviewedmentioning

confidence: 80%

Section: Discussionmentioning

confidence: 94%

Peer Review #1 of "Bacterial communities in the digester bed and liquid effluent of a microflush composting toilet system (v0.1)"

Murcott¹

2018

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“…The ability of the GSAP Microflush toilet to process waste is supported by previous studies investigating temperature distribution within the digester (Mecca, Stifler & Beley, 2017) and the use of SODIS for pathogen reduction in liquid effluent (Mecca, Pellock & Bretz, 2013b). In addition, studies of vermicomposting as a waste treatment method have demonstrated the effectiveness of this approach for mass reduction and pathogen removal (Hill & Baldwin, 2012; Soobhany, Mohee & Garg, 2017).…”

Section: Introductionmentioning

confidence: 76%

Bacterial communities in the digester bed and liquid effluent of a microflush composting toilet system

Williams

Kleinschmidt

Mecca

2018

PeerJ

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Lack of access to clean water and sanitation is a major factor impacting public health in communities worldwide. To address this, the S-Lab at Providence College and the Global Sustainable Aid Project developed a microflush composting toilet system to isolate and treat human waste. Solid waste is composted within a filter-digester bed via an aerobic process involving microbes and invertebrates. Liquid waste may be sanitized by solar disinfection (SODIS) or slow sand filtration (SSF). Here, we used 16S rRNA amplicon sequencing of samples from a scaled-down test version of the system to better understand the bacterial component of the toilet system. Immediately after fecal matter was deposited in the test system, the bacterial community of the filter-digester bed at the site of deposition resembled that of the human gut at both the phylum and genus level, which was expected. Genus-level analysis of filter-digester bed samples collected over the next 30 days from the site of deposition showed reduced or undetectable levels of fecal-associated taxa, with the exception of Clostridium XI, which persisted at low abundance throughout the sampling period. Starting with the sample collected on day 4, the bacterial community of the filter-digester bed at the site of deposition was dominated by bacterial taxa commonly associated with environmental sources, reflecting a major shift in bacterial community composition. These data support the toilet system’s capacity for processing solid human waste. We also analyzed how SODIS and SSF sanitization methods affected the bacterial community composition of liquid effluent collected on day 15 from the test system. Untreated and treated liquid effluent samples were dominated by Proteobacteria. At the genus level, the bacterial community of the untreated effluent included taxa commonly associated with environmental sources. In the SODIS-treated effluent, these genera increased in abundance, whereas in the SSF-treated effluent, they were greatly reduced or undetectable. By analyzing operational taxonomic units that were unclassified at the genus level, we observed that SSF appears to introduce new taxa into the treated effluent, likely from the biological film of microbes and small animals that constitutes the key element of SSF. These data will inform continued development of liquid waste handling strategies for the toilet system. Using the test system as an indicator of the performance of the full-scale version, we have shown the effectiveness of the microflush composting toilet system for containing and eliminating gut-associated bacteria, thereby improving sanitation and contributing to better public health in rural and peri-urban communities.

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“…Water purification in the WASH+E system is accomplished with a combination of slow sand filtering (SSF) and SODIS. The effectiveness of the latter has been modeled, measured and reported [4]. In all of the WASH+E interventions the emphasis is on effectiveness and cost.…”

Section: A Potable Water Purification Systemmentioning

confidence: 99%

The S-Lab’s Wash+e System: Ten Sustainable Interventions for Vernacular Rural Households in Developing Communities

Mecca¹,

Reilly²,

Kleinschmidt³

et al. 2017

WIT Transactions on Ecology and the Environment

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The GSAP Microflush toilet system, a locally sourced fabricated toilet that features a macro-organismenhanced aerobic filter-digester and an innovative valve that flushes on just 150 cc of water has proven to be an effective sustainable sanitation solution for developing world tropical communities. When coupled with 9 low-cost WASH and energy interventions, the resulting WASH+E system can add health, wellness and other value to a basic rural household. This paper describes each of the interventions including the components, options and costs. Lab prototypes are shown with early results from application deployments in Ghana, Haiti and Nicaragua. GSAP expects the technology to go to scale in multiple models including an extension of its toilet MAKER model, DIY contributions from recipient households and community cooperatives, especially coops involving women.

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Pathogen removal options: emphasizing SOLDIS for the filtrate of a GSAP Microflush toilet

Cited by 4 publications

References 6 publications

Peer Review #1 of "Bacterial communities in the digester bed and liquid effluent of a microflush composting toilet system (v0.1)"

Peer Review #1 of "Bacterial communities in the digester bed and liquid effluent of a microflush composting toilet system (v0.1)"

Bacterial communities in the digester bed and liquid effluent of a microflush composting toilet system

The S-Lab’s Wash+e System: Ten Sustainable Interventions for Vernacular Rural Households in Developing Communities

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