No Cover Image

Journal article 208 views 40 downloads

Valorising nutrient-rich digestate: Dilution, settlement and membrane filtration processing for optimisation as a waste-based media for microalgal cultivation / Fleuriane Fernandes, Alla Silkina, 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

  • 55157.pdf

    PDF | Version of Record

    © 2020 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 4.0 (CC BY) License.

    Download (1.28MB)

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...

Full description

Published in: Waste Management
ISSN: 0956-053X
Published: Elsevier BV 2020
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa55157
Tags: Add Tag
No Tags, Be the first to tag this record!
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.
Keywords: Digestate, Membrane filtration, Settlement and dilution, Microalgae, Chlorella vulgaris, Pilot-scale
College: College of Science
Start Page: 197
End Page: 208