Accumulation of TiO2 nanoparticles in the anammox bioreactor: Their effects on treatment performance and microbial dynamics

• Published in: Biochemical engineering journal 2022-11, Vol.187, p.108595, Article 108595
• Main Authors: Sari, Tugba, Akgul, Deniz, Mertoglu, Bulent
• Format: Article
• Language: English
• Subjects: Long-term inhibition; Microbial structure analysis; Nanoparticle accumulation; Novel nitrogen removal; Toxicity; Wastewater treatment
• ISSN: 1369-703X; 1873-295X
• DOI: 10.1016/j.bej.2022.108595

Nanotechnology applications have significant beneficial impacts on society however, the possible adverse effects of nanoparticles (NPs) lead to great concern from the environmental perspective because of their overproduction, overconsumption, and unintentional release to the wastewater. The main goal of the study was to investigate the long-term effects of titanium dioxide (TiO2) NPs on the Anammox process, considering the accumulation of NPs on biological systems over time, in terms of nitrogen treatment capacity, extracellular polymeric substances content, and microbial dynamics. Anammox population was found to be vulnerable to the elevated TiO2 NPs concentration. Persistent deterioration on nitrogen removal was observed at 200 mg/L NPs dose upon following 585 days of exposure. NH4+-N and NO2--N removal efficiencies decreased from 97.65 % ± 1.63 to 15.84 % and 98.7 % ± 1.84 to 8.69 %, respectively. At the inhibition dose, total Ti content was found to be 1.9 g/L Ti and 65.24 % of which was associated to the biomass. It reveals that, most of the accumulated Ti within the bioreactor deposited on the microorganisms, which may decrease substrate utilization. During the exposure period, relative abundance of Candidatus Brocadiaceae was almost stable up to 200 mg/L NPs dose and at this dose, its abundance decreased by 9.75 %. [Display omitted] •Assessment of long-term nanoparticle exposure in wastewater treatment is crucial.•TiO2 NPs were found to deposit in the reactor and on the surface of microorganisms.•Accumulated Ti concentration in the reactor at the inhibition dose was 1.9 g/L.•High TiO2 NPs concentration decreases the relative abundance of anammox bacteria.