Phenol and nitrogen removal in microalgal–bacterial granular sequential batch reactors

BUCCI, PAULA; GARCÍA?DEPRAECT, OCTAVIO; MONTERO, ENRIQUE JOSÉ MARCOS; ZARITZKY, NOEMÍ; CARAVELLI, ALEJANDRO; MUÑOZ, RAÚL

JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY

JOHN WILEY & SONS LTD

Año: 2023

0268-2575

BACKGROUND: Microalgal–bacterial systems work on the principle of the symbiotic relationship between algae and bacteria.The ability of algal–bacterial photobioreactors for the treatment of wastewater containing ammonia and phenol has beenpoorly addressed. In this work a self-sustaining synergetic microalgal–bacterial granular sludge process was thus developedto treatment of industrial wastewater based upon the low cost of photosynthetic oxygenation and the simultaneous phenoland nitrogen removal. The performance of a conventional sequential batch reactor (SBR) based on aerobic bacterial communities(SBRB) and a microalgal–bacterial granular SBR (SBRMB) were comparatively assessed. The major challenges associated withmicroalgal–bacterial systems were discussed.RESULTS: A complete removal of phenol (100 mg L−1) was achieved in both reactors. The reactors SBRB and SBRMB showed similarperformance in term of removal of inorganic nitrogen. Nitrogen mass balances estimated nitrogen assimilation, nitrificationand denitrification. Higher simultaneous nitrification and denitrification (70% SND) occurred in SBRB as determined by massbalances. The higher nitrogen assimilation (17.9%) by the microalgal–bacterial biomass compensated the lower denitrifyingactivity in SBRMB (54% SND), resulting in a removal of inorganic nitrogen (61%) similar to that obtained in SBRB (66%). N2Owas not detected in the headspace of any system.CONCLUSION: Granular microalgal–bacterial consortia implemented in SBR constitute an efficient method for industrial wastewatertreatment achieving complete removal of ammonia and phenol. The application of SBRMB would be more cost effectivethan SBRB mainly due to the significant energy savings in SBRMB resulting in a sustainable system that contributes to the circularbioeconomy.