Effect of anaerobic digestate fuel pellet production on Enterobacteriaceae and Salmonella persistence
Abstract Production of digestate pellets for fuel has been identified as a promising circular economy approach to provide renewable energy and additional income to farms, while at the same time presenting the potential to divert raw digestate from nutrient‐saturated land and reduce the risk to water...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2022-09-01
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| Series: | GCB Bioenergy |
| Subjects: | |
| Online Access: | https://doi.org/10.1111/gcbb.12986 |
| _version_ | 1811322749157638144 |
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| author | Ashley Cathcart Beatrice M. Smyth Christina Forbes Gary Lyons Simon T. Murray David Rooney Christopher R. Johnston |
| author_facet | Ashley Cathcart Beatrice M. Smyth Christina Forbes Gary Lyons Simon T. Murray David Rooney Christopher R. Johnston |
| author_sort | Ashley Cathcart |
| collection | DOAJ |
| description | Abstract Production of digestate pellets for fuel has been identified as a promising circular economy approach to provide renewable energy and additional income to farms, while at the same time presenting the potential to divert raw digestate from nutrient‐saturated land and reduce the risk to water quality. Although previous research has investigated the feasibility of pellet production, there has been little focus on the bio‐safety aspects of the system. Little is currently known about the persistence of bacteria present in the digestate and the potential impacts on human health for those handling this product. The aim of the present research was to determine the effect that each step in the pellet production process has on bacteria numbers: anaerobic digestion, mechanical separation, solid drying, and pelletisation. Enterobacteriaceae enumeration by colony count method was used to quantify bacteria, and the presence of Salmonella at each stage was determined. The Enterobacteriaceae count reduced with each stage, and the final pelletisation step reduced bacteria numbers to below detectable levels (<10 colony forming units/g). Salmonella was only detected in the starting slurry and absent from digestate onwards. Storage of the pellets under winter and simulated summer conditions showed no reactivation of Enterobacteriaceae over time. The pelletisation process produces a digestate product with Enterobacteriaceae counts below the maximum threshold (PAS110 specification) for transport off the source farm, but care must still be taken when handling digestate pellets as complete sterilisation has not been confirmed. |
| first_indexed | 2024-04-13T13:41:35Z |
| format | Article |
| id | doaj.art-b9aa4d0c84b64779afcb083742872681 |
| institution | Directory Open Access Journal |
| issn | 1757-1693 1757-1707 |
| language | English |
| last_indexed | 2024-04-13T13:41:35Z |
| publishDate | 2022-09-01 |
| publisher | Wiley |
| record_format | Article |
| series | GCB Bioenergy |
| spelling | doaj.art-b9aa4d0c84b64779afcb0837428726812022-12-22T02:44:38ZengWileyGCB Bioenergy1757-16931757-17072022-09-011491055106410.1111/gcbb.12986Effect of anaerobic digestate fuel pellet production on Enterobacteriaceae and Salmonella persistenceAshley Cathcart0Beatrice M. Smyth1Christina Forbes2Gary Lyons3Simon T. Murray4David Rooney5Christopher R. Johnston6School of Mechanical and Aerospace Engineering Queen's University Belfast Belfast UKSchool of Mechanical and Aerospace Engineering Queen's University Belfast Belfast UKFaculty of Science Atlantic Technological University Letterkenny Republic of IrelandAgri‐Food and Biosciences Institute Hillsborough UKCASE (Centre for Advanced Sustainable Energy) Queen's University Belfast Belfast UKSchool of Chemistry and Chemical Engineering Queen's University Belfast Belfast UKAgri‐Food and Biosciences Institute Hillsborough UKAbstract Production of digestate pellets for fuel has been identified as a promising circular economy approach to provide renewable energy and additional income to farms, while at the same time presenting the potential to divert raw digestate from nutrient‐saturated land and reduce the risk to water quality. Although previous research has investigated the feasibility of pellet production, there has been little focus on the bio‐safety aspects of the system. Little is currently known about the persistence of bacteria present in the digestate and the potential impacts on human health for those handling this product. The aim of the present research was to determine the effect that each step in the pellet production process has on bacteria numbers: anaerobic digestion, mechanical separation, solid drying, and pelletisation. Enterobacteriaceae enumeration by colony count method was used to quantify bacteria, and the presence of Salmonella at each stage was determined. The Enterobacteriaceae count reduced with each stage, and the final pelletisation step reduced bacteria numbers to below detectable levels (<10 colony forming units/g). Salmonella was only detected in the starting slurry and absent from digestate onwards. Storage of the pellets under winter and simulated summer conditions showed no reactivation of Enterobacteriaceae over time. The pelletisation process produces a digestate product with Enterobacteriaceae counts below the maximum threshold (PAS110 specification) for transport off the source farm, but care must still be taken when handling digestate pellets as complete sterilisation has not been confirmed.https://doi.org/10.1111/gcbb.12986anaerobic digestionanimal by‐productsdigestateEnterobacteriaceaefuel pelletmechanical separation |
| spellingShingle | Ashley Cathcart Beatrice M. Smyth Christina Forbes Gary Lyons Simon T. Murray David Rooney Christopher R. Johnston Effect of anaerobic digestate fuel pellet production on Enterobacteriaceae and Salmonella persistence GCB Bioenergy anaerobic digestion animal by‐products digestate Enterobacteriaceae fuel pellet mechanical separation |
| title | Effect of anaerobic digestate fuel pellet production on Enterobacteriaceae and Salmonella persistence |
| title_full | Effect of anaerobic digestate fuel pellet production on Enterobacteriaceae and Salmonella persistence |
| title_fullStr | Effect of anaerobic digestate fuel pellet production on Enterobacteriaceae and Salmonella persistence |
| title_full_unstemmed | Effect of anaerobic digestate fuel pellet production on Enterobacteriaceae and Salmonella persistence |
| title_short | Effect of anaerobic digestate fuel pellet production on Enterobacteriaceae and Salmonella persistence |
| title_sort | effect of anaerobic digestate fuel pellet production on enterobacteriaceae and salmonella persistence |
| topic | anaerobic digestion animal by‐products digestate Enterobacteriaceae fuel pellet mechanical separation |
| url | https://doi.org/10.1111/gcbb.12986 |
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