Microbial community response to ciprofloxacin toxicity in sponge membrane bioreactor
Bao-Trong Dang1, Xuan-Thanh Bui2, Tomoaki Itayama3
1Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan; Ho Chi Minh City University of Technology (HUTECH) 475A, Dien Bien Phu, Ward 25, Binh Thanh District, Ho Chi Minh City, Viet Nam.
Abstract:
This study aims to offer insights into how ciprofloxacin (CIP) impact bacterial community structures in the Sponge-MBR process when CIP is spiked into hospital wastewater. We found that the CIP toxicity decreased richness critical phylotypes such as phylum class ẟ-, β-, ɣ-proteobacteria, and Flavobacteria that co-respond to suppress denitrification and cake fouling to 37% and 28% respectively. Cluster analysis shows that the different community structures were formed under the influence of CIP toxicity. CIP decreased attached growth biomass by 2.3 times while increasing the concentration of permeate nitrate by 3.8 times, greatly affecting TN removal by up to 26%. Ammonia removal was kept stable by inflating the ammonia removal rate (p < 0.003), with the wealthy Nitrospira genus guaranteeing the nitrification activity. In addition, we observed an increasing richness of Chloroflexi and Planctomycetes, which may play a role in fouling reduction in the Sponge-MBR. Therefore, if the amount of antibiotics in hospital wastewater continues to increase, it is so important to extend biomass retention for denitrification recovery.
Insights
Ciprofloxacin in hospital wastewater disrupts bacterial communities in Sponge-MBRs, reducing key microbes for denitrification and fouling control. Extended biomass retention is crucial for recovery.
Area of Science:
- Environmental Microbiology
- Wastewater Treatment Engineering
- Biotechnology
Background:
- Hospital wastewater often contains antibiotics like ciprofloxacin (CIP).
- Membrane Bioreactors (MBRs) are vital for wastewater treatment.
- The impact of CIP on Sponge-MBR microbial communities is not fully understood.
Purpose of the Study:
- To investigate the effects of ciprofloxacin (CIP) on bacterial community structures within the Sponge-MBR process.
- To understand how CIP influences key microbial functions like denitrification and fouling.
- To assess the implications for overall wastewater treatment efficiency.
Main Methods:
- Spiking hospital wastewater with ciprofloxacin (CIP) in a lab-scale Sponge-MBR.
- Analyzing bacterial community structures using microbial analysis techniques.
- Monitoring key performance indicators such as nutrient removal and biomass characteristics.
Main Results:
- CIP significantly decreased the richness of critical phylotypes (e.g., ẟ-, β-, ɣ-proteobacteria, Flavobacteria), impacting denitrification and cake fouling.
- Attached growth biomass was reduced by 2.3 times, while permeate nitrate increased by 3.8 times, affecting total nitrogen (TN) removal by 26%.
- Ammonia removal remained stable due to increased rates, supported by the Nitrospira genus; Chloroflexi and Planctomycetes richness increased, potentially aiding fouling reduction.
Conclusions:
- Ciprofloxacin significantly alters microbial communities in Sponge-MBRs, compromising denitrification and increasing nitrate levels.
- While nitrification is maintained, overall nitrogen removal is negatively impacted.
- Increased antibiotic concentrations necessitate extended biomass retention times for effective denitrification recovery in Sponge-MBRs.
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