Microalgae are photosynthetic microorganisms and are considered excellent candidates for biotechnological applications, including the removal of nutrients (N and P) from urban wastewaters. Microalgae, in fact, can recover and convert wastewater pollutants into biomass, which can be valorised through the production of molecules useful for energy, agricultural or feed sectors (Abeysiriwardana-Arachchige et al., 2020; Tang et al., 2020). Microalgae-based systems can be integrated into conventional urban wastewater treatment plants to improve the water depuration process. Nowadays technologies used for nutrients removal are usually complex and expensive, so, the employment of microalgae represents a more sustainable approach (Abeysiriwardana-Arachchige et al., 2020). An effective microalgal strain selection represents a crucial step for suitable phytoremediation. Since the isolation and maintenance of individual microalgal strains is often difficult, the use of microalgae consortia in the wastewater treatment process appears to be advantageous. Gonçalves et al. (2017) reported that nutrient uptake is improved through positive interactions between co-cultivated microalgal strains, and this system tends to be more responsive to environmental conditions variations. This study is part of an ongoing research project POR-FERS 2014-2020 granted by Emilia Romagna region (Italy). The research aims to investigate the potential of co-cultivation of three autochthonous microalgae for N and P removal using effluents deriving from the thickening stage of the urban wastewater treatment plant managed by HERA SpA (Ferrara). Growth and nutrients removal ability of the microalgal consortium were assessed both in the thickening effluent and in synthetic medium, with same N and P concentrations, used as control. Nutrients removal was also measured in the effluent without microalgae. Morphological aspects, protein content, photosynthetic pigments, and photosynthetic efficiency of PSII were also evaluated. Interestingly, cells cultivated in the effluent showed higher growth rate and a better capability to remove nutrients than those grown in synthetic modified medium. In fact, NH4+-N was reduced by 63% and PO43--P by around 70% in 14 days of cultivation. On the contrary, nutrients removal did not take place in synthetic medium cultures. The nitrification process occurred in all sample, but it was higher where microalgae were not present. Moreover, since the algal biomass after nutrients removal was enriched in proteins and photosynthetic pigments, it can be proposed as a feed supplement or agricultural fertilizer. This work was granted by a POR-FESR 2014-2020 Project - Emilia Romagna, Italy (VALUE CE-IN "VALorizzazione di acque reflUE e fanghi in ottica di economia CircolarE e simbiosi INdustriale").
Removal of nitrogen and phosphorous from urban wastewater streams by a consortium of three autochthonous microalgae.
Demaria S.;Baldisserotto C.;Marchesini R.;Ferroni L.;Pancaldi S.
2021
Abstract
Microalgae are photosynthetic microorganisms and are considered excellent candidates for biotechnological applications, including the removal of nutrients (N and P) from urban wastewaters. Microalgae, in fact, can recover and convert wastewater pollutants into biomass, which can be valorised through the production of molecules useful for energy, agricultural or feed sectors (Abeysiriwardana-Arachchige et al., 2020; Tang et al., 2020). Microalgae-based systems can be integrated into conventional urban wastewater treatment plants to improve the water depuration process. Nowadays technologies used for nutrients removal are usually complex and expensive, so, the employment of microalgae represents a more sustainable approach (Abeysiriwardana-Arachchige et al., 2020). An effective microalgal strain selection represents a crucial step for suitable phytoremediation. Since the isolation and maintenance of individual microalgal strains is often difficult, the use of microalgae consortia in the wastewater treatment process appears to be advantageous. Gonçalves et al. (2017) reported that nutrient uptake is improved through positive interactions between co-cultivated microalgal strains, and this system tends to be more responsive to environmental conditions variations. This study is part of an ongoing research project POR-FERS 2014-2020 granted by Emilia Romagna region (Italy). The research aims to investigate the potential of co-cultivation of three autochthonous microalgae for N and P removal using effluents deriving from the thickening stage of the urban wastewater treatment plant managed by HERA SpA (Ferrara). Growth and nutrients removal ability of the microalgal consortium were assessed both in the thickening effluent and in synthetic medium, with same N and P concentrations, used as control. Nutrients removal was also measured in the effluent without microalgae. Morphological aspects, protein content, photosynthetic pigments, and photosynthetic efficiency of PSII were also evaluated. Interestingly, cells cultivated in the effluent showed higher growth rate and a better capability to remove nutrients than those grown in synthetic modified medium. In fact, NH4+-N was reduced by 63% and PO43--P by around 70% in 14 days of cultivation. On the contrary, nutrients removal did not take place in synthetic medium cultures. The nitrification process occurred in all sample, but it was higher where microalgae were not present. Moreover, since the algal biomass after nutrients removal was enriched in proteins and photosynthetic pigments, it can be proposed as a feed supplement or agricultural fertilizer. This work was granted by a POR-FESR 2014-2020 Project - Emilia Romagna, Italy (VALUE CE-IN "VALorizzazione di acque reflUE e fanghi in ottica di economia CircolarE e simbiosi INdustriale").I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
