RT info:eu-repo/semantics/article T1 Assessing the influence of the hydraulic retention time and carbon/nitrogen ratio on urban wastewater treatment in a new anoxic-aerobic algal-bacterial photobioreactor configuration A1 Toledo Cervantes, Alma A1 Posadas, Esther A1 Bertol, Isabel A1 Turiel Santos, Sara A1 Alcoceba, Ana A1 Muñoz Torre, Raúl K1 Algal-bacterial processes K1 Procesos alga-bacteria K1 Anoxic-aerobic photobioreactor K1 Fotobiorreactor anóxico-aerobio K1 Carbon-to-nitrogen ratio K1 Relación carbono/nitrógeno AB The influence of the hydraulic retention time (HRT) (2 and 4 days) and the carbon/nitrogen ratio (C/N) (7, 8 and 9) of the wastewater on the treatment of synthetic domestic wastewater was evaluated in a new anoxic-aerobic algal-bacterial photobioreactor configuration operated at solids retention time of 10 d by biomass recycling and withdrawal. The removal of chemical oxygen demand remained between 84% and 89% regardless of the operational conditions. However, the decrease in the HRT from 4 to 2 d entailed reductions in the removal of total nitrogen (TN) and P-PO43− from 87 ± 2% to 62 ± 2% and from 22 ± 5% to 11 ± 1%, respectively. On the other hand, the decrease in the C/N ratio of the wastewater from 9 to 8 and 7 at a HRT of 2 d induced TN removals of 62 ± 4% and 48 ± 4%, respectively. In contrast, P-PO43- removals unexpectedly increased from 11 ± 1% at a C/N ratio of 9 to 53 ± 3% and 47 ± 5% at C/N ratios of 8 and 7, respectively. Finally, biomass settling and recycling supported the enrichment of an algal-bacterial population with good settleability characteristics (suspended solids removals in the settler ∼98%), being Chlorella vulgaris the dominant microalga specie at a C/N ratio of 9 which was gradually replaced by Phormidium sp., as a result of the reduction in the C/N ratio of the wastewater. PB Elsevier SN 2211-9264 YR 2019 FD 2019 LK http://uvadoc.uva.es/handle/10324/46466 UL http://uvadoc.uva.es/handle/10324/46466 LA eng NO Algal Research, 2019, vol. 44. 8 p. NO Producción Científica DS UVaDOC RD 26-abr-2024