Recirculating packed¿bed biofilm photobioreactor combined with membrane ultrafiltration as advanced wastewater treatment
Date
2023Abstract
Packed-bed bioflm photobioreactor combined with ultrafltration membrane was investigated for intensifying the process for secondary wastewater efuent treatment. Cylindrical glass carriers were used as supporting material for the microalgal-bacterial
bioflm, which developed from indigenous microbial consortium. Glass carriers allowed adequate growth of the bioflm with limited suspended biomass. Stable operation was achieved after a start-up period of 1000 h, where supernatant biopolymer clusters
were minimized and complete nitrifcation was observed. After that time, biomass productivity was 54±18 mg·L−1·day−1. Green microalgae Tetradesmus obliquus and several strains of heterotrophic nitrifcation–aerobic denitrifcation bacteria and fungi were identifed. Combined process exhibited COD, nitrogen and phosphorus removal rates of 56±5%, 12±2% and 20±6%,
respectively. Membrane fouling was mainly caused by bioflm formation, which was not efectively mitigated by air-scouring aided backwashing