The effect of interstitial surface spacing on algal biomass accumulation

It has been shown that increased control over the cultivation process of benthic algae augments yields and efficiencies in pollution recovery and biofuel production. Algal Turf Scrubber (ATS) technology allows for cultivation of benthic algae for water remediation. Additive Manufacturing (3D Printing) has shown to be a versatile tool that allows for design and fabrication of complex surfaces for algal cultivation. The objective of this study was to investigate the effect of different interstitial surface area distribution on the early onset colonization of benthic algae by measurement of biomass in a laboratory-based Algal Turf Scrubber (ATS) apparatus. Three replicates using twenty-one 3D-printed plates with randomized sections and layout were deployed inside an ATS under controlled conditions for eleven days. Each 4-section plate (192 mm × 48 mm) was fabricated using Fused Deposition Modeling (FDM) technology-extruding PLA (Polylactic Acid) printed with a 100 μm layer thickness. The results show that the greater biomass density was carried on treatments with interstitial regions (pockets). The presence of pockets significantly increased the biomass density (biomass per unit area) compared to the smooth (0 pocket) control. Based upon measurements over multiple days of algal cultivation, biomass accumulation rate in the interstitial spaces could be described by a logistic model and can find explanation through analysis by computational fluid dynamic (CFD) modeling.