Influence of hydraulic retention time on municipal wastewater treatment using microalgae-bacteria flocs in sequencing batch reactors

Publikationstyp
Journal Article
Date Issued
2022-02
Sprache
English
Author(s)
Soroosh, Hadi  
Otterpohl, Ralf  
Hanelt, Dieter  
Institut
Abwasserwirtschaft und Gewässerschutz B-2  
TORE-URI
http://hdl.handle.net/11420/11295
Journal
Bioresource technology reports  
Volume
17
Article Number
100884
Citation
Bioresource Technology Reports 17: 100884 (2022-02)
Publisher DOI
10.1016/j.biteb.2021.100884
Scopus ID
2-s2.0-85119991370
Real wastewater was treated with a consortium of indigenous microalgae and bacteria (MaB) in sequencing batch reactors (SBR) while the hydraulic retention time (HRT) reduced from of 3 days (5 batches) to 2 days (6 batches). Biomass uptake and nitrification were the main ammonium removal pathways (about 96% for both HRTs) and phosphate levels stayed within the European limit of 1 mg P L−1. The alkalization due to lack of inorganic carbon triggered free ammonia inhibition and partial nitrification. Consequently, the total nitrogen removal could not satisfy the EU standard. Extreme pH levels (pH > 9.5) occurred more frequently in the SBR with HRT of 3 days, leading to culture collapse and biomass washout. Maintaining the pH below 8.0 seems crucial for an efficient treatment. The pH of the SBR with HRT of 2 days was more moderate, making this HRT advantageous for the single-step MaB treatment of weak wastewaters.
Subjects
ammonia inhibition
Inorganic carbon
Nitrification
Nitrite accumulation
Nitrogen removal
pH inhibition