Highly efficient carbon assimilation and nitrogen/phosphorus removal facilitated by photosynthetic O₂ from algal-bacterial aerobic granular sludge under controlled DO/pH operation

Highly efficient carbon assimilation and nitrogen/phosphorus removal facilitated by photosynthetic O₂ from algal-bacterial aerobic granular sludge under controlled DO/pH operation

Li, Zejiao (University of Tsukuba)
Wang, Jixiang (University of Tsukuba)
Liu, Jialin (University of Tsukuba)
Chen, Xingyu (University of Tsukuba)
Lei, Zhongfang (University of Tsukuba)
Yuan, Tian (University of Tsukuba)
Lee, Duu Jong (City University of Hong Kong; Yuan Ze University, Chung-Li)
Lin, Y. (TU Delft Environmental Fluid Mechanics)
van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology)

2023

Reducing CO₂ emission and energy consumption is crucial for the sustainable management of wastewater treatment plants (WWTPs). In this study, an algal-bacterial aerobic granular sludge (AGS) system was developed for efficient carbon (C) assimilation and nitrogen (N)/phosphorus (P) removal without the need for mechanical aeration. The photosynthetic O₂ production by phototrophic organisms maintained the dissolved oxygen (DO) level at 3-4 mg/L in the bulk liquid, and an LED light control system reduced 10–30% of light energy consumption. Results showed that the biomass assimilated 52% of input dissolved total carbon (DTC), and the produced O₂ simultaneously facilitated aerobic nitrification and P uptake with the coexisting phototrophs serving as a C fixer and O₂ supplier. This resulted in a stably high total N removal of 81 ± 7% and an N assimilation rate of 7.55 mg/(g-MLVSS∙d) with enhanced microbial assimilation and simultaneous nitrification/denitrification. Good P removal of 92–98% was maintained during the test period at a molar ∆P/∆C ratio of 0.36 ± 0.03 and high P release and uptake rates of 10.84 ± 0.41 and 7.18 ± 0.24 mg/(g- MLVSS∙h), respectively. Photosynthetic O₂ was more advantageous for N and P removal than mechanical aeration. This proposed system can contribute to a better design and sustainable operation of WWTPs using algal-bacterial AGS.

Algal-bacterial aerobic granular sludge
Carbon fixation
Nitrogen assimilation
Photosynthetic oxygen
Simultaneous nitrogen and phosphorus removal

http://resolver.tudelft.nl/uuid:1a997c5a-df01-48f8-b5ad-aea533d854ea

https://doi.org/10.1016/j.watres.2023.120025

2023-12-30

0043-1354

Water Research, 238

Institutional Repository

journal article

© 2023 Zejiao Li, Jixiang Wang, Jialin Liu, Xingyu Chen, Zhongfang Lei, Tian Yuan, Duu Jong Lee, Y. Lin, Mark C.M. van Loosdrecht, More Authors