Understanding the algal contribution in combined UV-algae treatment to remove antibiotic cefradine

Abstract

The aim of this study is to investigate the algal contribution in a combined UV-algae treatment to remove the commonly used antibiotic cefradine. We evaluated the removal capacity of the individual alga (Chlorella pyrenoidosa), UV activated and combined UV-algae treatments. The toxic effect of the effluents treated by the above process on the standard test organism rotifer (Brachionus calyciflorus) was also investigated. Our results showed that the individual algae treatment was inefficient at removing the antibiotic. Although the UV treatment decreased the antibiotic concentration efficiently (26.93% residue), it also increased the toxicity of the effluent (1.04 times of the parent compound). However, the relatively high removal efficiency (22.01% residue) and the reduced toxicity of the effluent (nearly half of that by the individual UV treatment) were obtained synchronously after the UV-algae combined treatment. The contribution of the algae was also confirmed by investigating the corresponding properties of the combined UV-activated sludge treatment and the combined UV-activated sludge-algae treatment. Our present study supported our hypothesis that (1) the performance of the individual algae treatment was inferior to the individual UV irradiation; (2) the algae treatment was necessary in a UV-algae combined treatment system to control the toxicity of the effluent after the UV treatment process.