Microalgae-mediated bioremediation and valorization of cattle wastewater previously digested in a hybrid anaerobic reactor using a photobioreactor: Comparison between batch and continuous operation

• Published in: The Science of the total environment 2018-08, Vol.633, p.1-11
• Main Authors: de Mendonça, Henrique Vieira, Ometto, Jean Pierre Henry Balbaud, Otenio, Marcelo Henrique, Marques, Isabel Paula Ramos, dos Reis, Alberto José Delgado
• Format: Article
• Language: English
• Subjects: Cattle wastewater; CO2 fixation; Flat panel photobioreactor; Microalga; Nutrient removal
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.03.157

Scenedesmus obliquus (ACOI 204/07) microalgae were cultivated in cattle wastewater in vertical alveolar flat panel photobioreactors, operated in batch and continuous mode, after previous digestion in a hybrid anaerobic reactor. In batch operation, removal efficiencies ranges of 65 to 70% of COD, 98 to 99% of NH4+ and 69 to 77.5% of PO4−3 after 12days were recorded. The corresponding figures for continuous flow were from 57 to 61% of COD, 94 to 96% of NH4+ and 65 to 70% of PO4−3 with mean hidraulic retention time of 12days. Higher rates of CO2 fixation (327–547mgL−1d−1) and higher biomass volumetric productivity (213–358mgL−1d−1) were obtained in batch mode. This microalgae-mediated process can be considered promising for bioremediation and valorization of effluents produced by cattle breeding yielding a protein-rich microalgal biomass that could be eventually used as cattle feed. [Display omitted] •Cultivation of microalgae Scenedesmus obliquus with anaerobic cattle wastewater was investigated.•Maximum CODs removal in Batch was 70% and continuous 61%.•Removals above 96% (NH4+) and 70% (PO4−3) were recorded.•Better biomass productivity (358mgL−1d−1) was obtained in batch.•Productivity values for proteins, carbohydrates and lipids of 150, 110 and 64mgL−1d−1 were achieved.