Simultaneous nutrient removal and lipid production with Chlorella vulgaris on sterilized and non-sterilized anaerobically pretreated piggery wastewater

• Published in: Biochemical engineering journal Vol. 103; pp. 177 - 184
• Main Authors: Marjakangas, Jatta M., Chen, Chun-Yen, Lakaniemi, Aino-Maija, Puhakka, Jaakko A., Whang, Liang-Ming, Chang, Jo-Shu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2015
• Subjects: Aerobic process; Lipid production; Microalgae; Piggery wastewater; Sterilization; Wastewater treatment; Aerobic process; Lipid production; Microalgae; Piggery wastewater; Wastewater treatment; Sterilization
• ISSN: 1369-703X; 1873-295X
• DOI: 10.1016/j.bej.2015.07.011

[Display omitted] •C. vulgaris grew on sterilized and non-sterilized wastewater.•Higher lipid productivity (117g/L/d) was obtained with the sterilized wastewater.•Lipid productivity was quite promising with non-sterilized wastewater (70.5g/L/d).•C. vulgaris grew mainly photoautotrophically, which resulted in excretion of DOC. Piggery wastewater is a potent nutrient source for microalgal lipid production. Wastewater has been usually sterilized when used for microalgal cultivation. This is uneconomical in large-scale applications. Therefore, lipid productivity of Chlorella vulgaris CY5 using sterilized and non-sterilized diluted anaerobically pretreated piggery wastewater was studied in batch reactors. The maximum average lipid productivity was obtained after 12 days of incubation and it was higher with the sterilized wastewater than with the non-sterilized one (117g/L/d vs. 91.3g/L/d), due to the higher biomass concentration. Because of the unexpected increase of dissolved organic carbon (DOC) in the cultures, second experiment was conducted to characterize the composition of produced DOC in non-sterilized wastewater. Carbohydrate content increased in the liquid phase but decreased in the biomass after nitrogen had been exhausted. After 12 days of incubation, soluble chemical oxygen demand (CODs) was 414±56mg/L, biomass production was 2.8±0.15g/L, and lipid content was 30.3±1.2wt%. Average lipid productivity from day zero to day 12 was 70.5±1.1g/L/d. C. vulgaris removed nutrients from the non-sterilized wastewater and produced oleaginous biomass, although the lipid productivity was higher with sterilized wastewater.