Algal bioproducts derived from suspended solids in intensive land-based aquaculture

► We investigate the properties of suspended solids produced in land-based aquaculture systems. ► Harvested suspended solids were rich in valuable ω-3 and ω-6 fatty acids. ► Suspended solids offer potential as a bioresource for the production of biochar. ► Utilising suspended solids has potential to provide economic and environmental benefits. Land-based aquaculture produces suspended solids in culture pond and settlement pond waters that could be harvested as a bioresource. Suspended solids were quantified, characterised and harvested from these two sources to assess their suitability for conversion to bioproducts. The suspended solids of settlement ponds were less concentrated (87.6±24.7mgL−1) than those of culture ponds (131.8±8.8mgL−1), but had a higher concentration of microalgae (27.5±4.0%) and consequently higher particulate organic carbon (24.8±4.7%) and particulate nitrogen (4.0±0.8%). The microalgal community also differed between sources with a higher concentration of fatty acids in the biomass from settlement ponds. Consequently, biochar produced from biomass harvested from settlement ponds was higher in organic carbon and nitrogen, with a lower cation exchange capacity. In conclusion, we characterised a renewable and potentially valuable bioresource for algal bioproducts derived from suspended solids in intensive land-based aquaculture.