Pretreatment of saline antibiotic wastewater using marine microalga.

A green microalga Chlorella sp. isolated from marine environment was investigated for its potential to pretreat saline antibiotic wastewater containing amoxicillin (AMX). Through Biolog EcoPlate assay, the Chlorella sp. showed its unique carbon source metabolic patterns under autotrophic condition. In addition, the microalga could effectively remove AMX (>99%) under initial AMX concentrations ranging from 10 to 150 mg/L through a treatability test. In the continuous AMX treatment using a lab-scale membrane photobioreactor (MPBR), a stable AMX removal efficiency of 85.6 ± 3.8% was observed. Moreover, with the aid of a subsequent bacterial treatment, the microalgal-bacterial process (the Chlorella sp. pretreatment followed by either intertidal wetland sediment or activated sludge) can achieve simultaneous AMX removal of >99% and total organic carbon (TOC) removal of ∼80%. In general, the microalgal pretreatment showed its great potential in effective removal of antibiotic residues, which could greatly enhance the overall treatment efficiency of saline antibiotic wastewater.