Algal control by two-stage nanobubble technology in Taihu Lake

https://www.sciencedirect.com/science/article/abs/pii/S0013935124019844?utm_source=chatgpt.com

Highlights

• Two-stage nanobubble technology removes more than 90% of the algae.
• 2-MIB concentration less than 10 ng/L after two-stage nanobubble treatment.
• Decrease in ammonia nitrogen concentration after using two-stage nanobubbles.
• Increased abundance of functional nitrogen cycle genes when experiment finished.

Hydrodynamic cavitation and ozone nanobubble-coupled hydrodynamic cavitation 

have demonstrated effective algae control in laboratories, but their in-situ potential,

 especially impact on nutrient salt degradation and microbial communities remain 

unclear. This study applied two-stage nanobubble technology, combining hydrodynamic

 cavitation and ozone nanobubbles, in a 3300 m² semi-enclosed area of Taihu Lake to

 address these gaps. Results show that the technology efficiently controls algae, reduces

 odors, improves anaerobic conditions, and lowers ammonia nitrogen. Over 20 days, 

chlorophyll-a concentration reduced by 77.46% and cyanobacterial phycocyanin by 

89.47%. Additionally, the concentrations of 2-MIB, GSM, and DMTS fell below threshold 

values. Notably, the relative abundance of Cyanobacteria in sediment dropped from 

8.53% in the control area to only 1.59%–3.65% in the experimental area. The technology 

also achieved a significant reduction in ammonia nitrogen, with removal efficiencies of 

78.53% in the water column and 39.17% in sediments, though the removal of total phosphorus 

was limited. Furthermore, the two-stage nanobubble system enhanced the abundance of 

nitrogen-cycling microorganisms and genes in the water, while promoting nitrogen- and 

phosphorus-related microbial communities in sediments and inhibiting the 

cyanobacteria-associated genus Cyanobium PCC-6307. Thus, Two-stage nanobubble

 technology can be employed for in-situ algal control in aquatic ecosystems.