Journal article 1416 views 269 downloads
Valorising nutrient-rich digestate: Dilution, settlement and membrane filtration processing for optimisation as a waste-based media for microalgal cultivation
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Claudio Fuentes Grunewald ,
Ellie Wood,
Vanessa Ndovela,
Darren Oatley-Radcliffe ,
Robert Lovitt,
Carole Llewellyn
Waste Management, Volume: 118, Pages: 197 - 208
Swansea University Authors:
Fleuriane Fernandes, Alla Silkina , Claudio Fuentes Grunewald , Ellie Wood, Vanessa Ndovela, Darren Oatley-Radcliffe , Robert Lovitt, Carole Llewellyn
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DOI (Published version): 10.1016/j.wasman.2020.08.037
Abstract
Digestate produced from the anaerobic digestion of food and farm waste is primarily returned to land as a biofertiliser for crops, with its potential to generate value through alternative processing methods at present under explored. In this work, valorisation of a digestate resulting from the treat...
| Published in: | Waste Management |
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| ISSN: | 0956-053X |
| Published: |
Elsevier BV
2020
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa55157 |
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| Abstract: |
Digestate produced from the anaerobic digestion of food and farm waste is primarily returned to land as a biofertiliser for crops, with its potential to generate value through alternative processing methods at present under explored. In this work, valorisation of a digestate resulting from the treatment of kitchen and food waste was investigated, using dilution, settlement and membrane processing technology. Processed digestate was subsequently tested as a nutrient source for the cultivation of Chlorella vulgaris, up to pilot-scale (800L). Dilution of digestate down to 2.5% increased settlement rate and induced release of valuable compounds for fertiliser usage such as nitrogen and phosphorus. Settlement, as a partial processing of digestate offered a physical separation of liquid and solid fractions at a low cost. Membrane filtration demonstrated efficient segregation of nutrients, with micro-filtration recovering 92.38% of phosphorus and the combination of micro-filtration, ultra-filtration, and nano-filtration recovering a total of 94.35% of nitrogen from digestate. Nano-filtered and micro-filtered digestates at low concentrations were suitable substrates to support growth of Chlorella vulgaris. At pilot-scale, the microalgae grew successfully for 28 days with a maximum growth rate of 0.62 day−1 and dry weight of 0.86 g⋅L−1. Decline in culture growth beyond 28 days was presumably linked to ammonium and heavy metal accumulation in the cultivation medium. Processed digestate provided a suitable nutrient source for successful microalgal cultivation at pilot-scale, evidencing potential to convert excess nutrients into biomass, generating value from excess digestate and providing additional markets to the anaerobic digestion sector. |
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| Keywords: |
Digestate, Membrane filtration, Settlement and dilution, Microalgae, Chlorella vulgaris, Pilot-scale |
| College: |
Faculty of Science and Engineering |
| Funders: |
College paid. |
| Start Page: |
197 |
| End Page: |
208 |