Wastewater remediation andupcycling of their nutrients in microalgae can be optimized to obtain biomass of greater value, thanks to the innovative method developed by a group of Chinese and American researchers (Wang et al., 2021). (1)
Wastewater and microalgae
The growth of microalgae in wastewater is possible thanks to the presence of nutrients – nitrogen, phosphorus, organic carbon – in the wastewater. However, the resulting algal biomass can be contaminated by bacteria which reduce the possibilities of use. In addition to having 'often low in lipids and carbohydrates, reducing its value as livestock feed or as a precursor to higher-value chemical production'.
I ricercators they have therefore experienced a reversal of the process. Instead of putting the microalgae into the wastewater, they extracted the nutrients from the food service wastewater of the Washington University with a bio-electrochemical system and then administered them to microalgae grown separately in a photobioreactor.
The quality comparison of the algal biomass obtained with this method of upcycling it's clean. 'The results of this study demonstrated an effective approach to extract nutrients from wastewater for enhanced microalgae growth and improved biomass quality', explain the authors.
The harvest thus obtained, in comparison with that derived from the immersion of the algae in the same food wastewater, shows
- a biomass density of 8,3 times higher,
- a 1,4-fold higher lipid content (18,5 to 26,2%),
- a concentration of microalgae equal to 90% of the biomass, against about 30% of that obtained from cultivation in food wastewater.
Footnotes to the story
(1) Zixuan Wang, Christopher J. Hartline, Fuzhong Zhang, Zhen He (2021). Enhanced microalgae cultivation using wastewater nutrients extracted by a microbial electrochemical system, water research, Volume 206, 2021, 117722, ISSN 0043-1354, https://doi.org/10.1016/j.watres.2021.117722.
Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".