Removal of concentrated sulfamethazine by acclimatized aerobic sludge and possible metabolic products

Na Yang; Junfeng Wan; Shiju Zhao; Yan Wang

doi:10.7717/peerj.1359

Removal of concentrated sulfamethazine by acclimatized aerobic sludge and possible metabolic products

PeerJ. 2015 Nov 3:3:e1359. doi: 10.7717/peerj.1359. eCollection 2015.

Authors

Na Yang¹, Junfeng Wan², Shiju Zhao¹, Yan Wang¹

Affiliations

¹ School of Chemical Engineering and Energy, Zhengzhou University , Zhengzhou , China.
² School of Chemical Engineering and Energy, Zhengzhou University , Zhengzhou , China ; School of Civil and Environmental Engineering, Nanyang Technological University , Singapore , Singapore ; Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University , Singapore , Singapore.

Abstract

This article examined the biological removal of high concentrated sulfamethazine (SMZ) antibiotics by the acclimatized activated sludge in lab-scale SBRs system. The removal of SMZ was characterized by a quick adsorption and a slow process of biodegradation. The adsorption capacity of activated sludge for SMZ was 44 and 47 µg SMZ/g SS, respectively, with the initial SMZ concentrations of 1 and 2 mg/L. The adsorption process fitted pseudo-second-order kinetic model. In a series of batch studies, with the increase of initial SMZ concentration that were 1, 2, 3, 5, 7 and 9 mg/L, 56.0%, 51.3%, 42.2%, 29.5%, 25.0% and 20.8% of influent SMZ were biodegraded within 24 h of biological reaction, respectively. The Monod equation applied to simulate SMZ biodegradation had a good coefficient of determination (R2 > 0.99). Furthermore, the results of HPLC demonstrated that the SMZ was not completely removed by the acclimatized activated sludge. From the analysis of LC-MS, 4 intermediates of SMZ biodegradation were identified: Sulfanilic Acid, 4-amino-N-(4,6-dimethyl-2 pyrimidin) benzene sulfonamide, N-(4,6-dimethyl-2-pyrimidin)-4-N-(benzene sulfonamide) benzene sulfonamide, N-(4,6-dimethyl-2-pyrimidin)-4-N-(4,6-dimethyl pyrimidine) benzene sulfonamide, and N-(4,6-dimethyl-2-pyrimidin)-4-N-(3-dimethyl-4-N sodium benzene sulfonamide) benzene sulfonamide.

Keywords: Acclimatized activated sludge; Adsorption; Biodegradation; Metabolites; Sulfamethazine (SMZ).

Grants and funding

This work was supported by the National Natural Science Foundation of China (No. 21107100), the International Cooperation Project of Zhengzhou City (No. 121PPTGG360-9, 141PGJHZ535) and the Natural Science Fund for Excellent Young Scholars of Zhengzhou University (No. 1421324067). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.