Residual veterinary antibiotics have been detected in livestock wastewater treatment plants. Despite the long retention time, antibiotic treatment efficiency has shown clear limitations. In this study, we evaluated submerged membrane photobioreactors (SMPBR) during sulfonamide antibiotic-containing livestock wastewater treatment under mixotrophic and photoautotrophic conditions. The results showed that microalgal sulfur degradation and consumption under mixotrophic conditions accelerated the biomass concentration increase to 2800 mg VSS/L compared to the 1800 mg VSS/L measured under photoautotrophic conditions. Although microalgal metabolites, such as soluble microbial products and extracellular polymeric substances, might cause membrane fouling in the SMPBR, we proved that microalgae could remove sulfonamide and release degradation-associated sulfur, along with nitrogen and phosphorus. Moreover, this study confirms the statistical correlation between metabolites and sulfonamides. In summary, the results of this study provide promising insights into antibiotic-containing livestock wastewater treatment. (C) 2020 Elsevier Ltd. All rights reserved.

Background: Contact with livestock wastewater on farms and in communities can pose a risk to human and animal health. Methods: This cross-sectional study was conducted in 180 households and 24 pig farms (96 wastewater samples) to explore information about pig production, livestock waste management, antibiotic use, and to analyze antibiotic residues and microbial contamination, respectively. Results: Of the 120 households raising pigs, biogas systems were the most commonly used to treat animal waste (70%), followed by compositing (19%), and the remaining respondents discharged waste directly into drains or ponds (11%). The majority of respondents (78%) used antibiotics to treat and prevent disease in pigs, but 32% of them did not know of any disadvantages of antibiotic abuse. ELISA assays were performed on half of the wastewater samples (n = 48), demonstrating that residues of flouroquinolones and sulfonamides were present in 6.3% (3/48) and 22.9% (11/48) of tested samples, respectively. The average residual level of sulfamethazine was 27.8 ug/l. Further,E. coliconcentrations exceeding regulatory levels in Vietnam were found in nearly all samples.Salmonellaspp. was also found in 57.3% of samples, though prevalence rates varied across the different sites. Finally,G. lambliawas found in 8.4% of samples, andC. parvumwas found in 5.2% of samples. Conclusions: This study suggests that livestock wastewater carried potential harmful pathogens and antibiotic residues that could come into contact with humans in the community. Thus, appropriate operation and application of livestock wastewater treatment (such as biogas or composting) and management should be a continued focused.