The role of P content on the treatment and valorization of the liquid fraction of digestate, namely centrate, through microalgae-based technologies was evaluated in this study. The performance of four column photobioreactors, which were fed on diluted centrate with corrected (10 mg N/ mg P) and not modified (129 mg N/ mg P) N:P ratio, were monitored and compared. The results demonstrated that P shortage in the centrate affected neither the total nitrogen and COD removal rate nor the volumetric biomass productivity, suggesting that expensive addition of P salts is not necessary to maximize the efficiency of the process. On the contrary, the addition of P to the centrate promoted the ammonia oxidation process as higher nitrite production was observed in the photobioreactors with adjusted N:P ratio than in the ones fed with the non-adjusted N:P ratio. These findings were confirmed by fluorescence in-situ hybridization and quantitative PCR assays, which revealed a higher number of ammonia-oxidizing bacteria in the microalgal suspensions cultivated on centrate with P addition. In conclusion, the N:P ratio in the centrate seems to have a role in controlling the nitrification process rather than in the overall nutrient removal rate and biomass productivity of the microalgae-based system.
Bellucci, M., Marazzi, F., Ficara, E., Mezzanotte, V. (2020). Effect of N:P ratio on microalgae/nitrifying bacteria community in agro-digestate treatment. ENVIRONMENTAL AND CLIMATE TECHNOLOGIES, 24(2), 136-148 [10.2478/rtuect-2020-0061].
Effect of N:P ratio on microalgae/nitrifying bacteria community in agro-digestate treatment
Marazzi F.;Mezzanotte V.
2020
Abstract
The role of P content on the treatment and valorization of the liquid fraction of digestate, namely centrate, through microalgae-based technologies was evaluated in this study. The performance of four column photobioreactors, which were fed on diluted centrate with corrected (10 mg N/ mg P) and not modified (129 mg N/ mg P) N:P ratio, were monitored and compared. The results demonstrated that P shortage in the centrate affected neither the total nitrogen and COD removal rate nor the volumetric biomass productivity, suggesting that expensive addition of P salts is not necessary to maximize the efficiency of the process. On the contrary, the addition of P to the centrate promoted the ammonia oxidation process as higher nitrite production was observed in the photobioreactors with adjusted N:P ratio than in the ones fed with the non-adjusted N:P ratio. These findings were confirmed by fluorescence in-situ hybridization and quantitative PCR assays, which revealed a higher number of ammonia-oxidizing bacteria in the microalgal suspensions cultivated on centrate with P addition. In conclusion, the N:P ratio in the centrate seems to have a role in controlling the nitrification process rather than in the overall nutrient removal rate and biomass productivity of the microalgae-based system.File | Dimensione | Formato | |
---|---|---|---|
N P ratio.pdf
accesso aperto
Tipologia di allegato:
Publisher’s Version (Version of Record, VoR)
Dimensione
496.17 kB
Formato
Adobe PDF
|
496.17 kB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.