Comparison between coagulation-flocculation and ozone-flotation for Scenedesmus microalgal biomolecule recovery and nutrient removal from wastewater in a high-rate algal pond

Abstract

The removal of nutrients by Scenedesmus sp. in a high-rate algal pond, and subsequent algal separation by coagulation-flocculation or flotation with ozone to recover biomolecules, were evaluated. Cultivation of Scenedesmus sp. in wastewater resulted in complete NH-H removal, plus 93% total nitrogen and 61% orthophosphate removals. Ozone-flotation obtained better water quality results than coagulation-flocculation for most parameters (NH-N, NTK, nitrate and nitrite) except orthophosphate. Ozone-flotation, also produced the highest recovery of lipids, carbohydrates and proteins which were 0.32 ± 0.03, 0.33 ± 0.025 and 0.58 ± 0.014 mg/mg of biomass, respectively. In contrast, there was a low lipid extraction of 0.21 mg of lipids/mg of biomass and 0.12-0.23 mg of protein/mg of biomass in the coagulation-flocculation process. In terms of biomolecule recovery and water quality, ozone showed better results than coagulation-flocculation.

A multidisciplinary review ofTetradesmus obliquus: a microalga suitable for large‐scale biomass production and emerging environmental applications

“…processes, these processes still represent a limiting step to the microalgae biomass production chain (Oliveira et al . 2018; De Melo Aguiar et al . 2019; Xue et al .…”

Flotation in Water and Wastewater Treatment

“…The removal of nutrients by Scenedesmus sp. in a high-rate algal pond and subsequent algal separation by coagulation-flocculation or flotation with ozone to recover biomolecules, was elsewhere evaluated [43].…”

Characterization of a Microalgal UV Mutant for CO2 Biofixation and Biomass Production

“…As shown in Figure 2(a), whether under air or 15 % CO 2 , the protein contents in PS were significantly higher than their lipid and carbohydrate contents, which agreed with recent reports, representing 32-58% of protein contents in Scenedesmus sp. [5, 23, 26, 39, 40]. However, in mutant SDEC-1M, the contents of lipid and carbohydrate were significantly higher than in PS, while the protein contents were just the opposite.…”