Long-term effects of heavy metals and antibiotics on granule-based anammox process: granule property and performance evolution
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The feasibility of the anaerobic ammonium oxidation (anammox) process to treat synthetic swine wastewater containing antibiotics and heavy metals was studied in this work. Nitrogen removal performance and granule characteristics were tracked by continuous-flow monitoring to evaluate the long-term joint effects of Cu and Zn and of Cu and oxytetracycline (OTC). Cu and Zn with a joint loading rate (JLR) of 0.04 kg m−3 day−1 did not affect the performance, while a JLR of 0.12 kg m−3 day−1 caused a rapid collapse in performance. Cu and OTC addition with a JLR of 0.04 kg m−3 day−1 for approximately 2 weeks induced significant nitrite accumulation. Granule characteristic analysis elucidated the disparate inhibition mechanisms of heavy metals and antibiotics: the internalization of heavy metals caused metabolic disorders, whereas OTC functioned as a growth retarder. However, anammox reactors could adapt to a JLR of 0.04 kg m−3 day−1 via self-regulation during the acclimatization to subinhibitory concentrations, which had a stable nitrogen removal rate (>8.5 kg m−3 day−1) and removal rate efficiency (>75 %) for reactors with Cu-OTC addition. Therefore, this study supports the great potential of using anammox granules to treat swine wastewater.
KeywordsAnammox Swine wastewater Heavy metal inhibition Antibiotic inhibition Sludge characteristics
The authors wish to thank the National Key Technologies R&D Program of China (No. 2012BAC13B02), the Public Welfare Project of Science Technology Department of Zhejiang Province, the Xinmiao Talent Program of Zhejiang Province (No. 2015R423074), and the Xingguang Program of Hangzhou Normal University for their partial support of this study.
Compliance with ethical standards
This study was funded by the National Key Technologies R&D Program of China (No. 2012BAC13B02), the Public Welfare Project of Science Technology Department of Zhejiang Province, the Xinmiao Talent Program of Zhejiang Province (No. 2015R423074), and the Xingguang Program of Hangzhou Normal University.
Conflict of interest
The corresponding author on behalf of all authors of the paper declares no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
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