Removal Characteristics of Effluent Organic Matter (EfOM) in Pharmaceutical Tailwater by a Combined Coagulation and UV/O3 Process

Jian Wang,Cong Du,Huibin Yu,Liancheng Xiang,Yonghui Song,Feng Qian

doi:10.3390/w12102773

Abstract

A novel coagulation combined with UV/O3 process was employed to remove the effluent organic matter (EfOM) from a biotreated pharmaceutical wastewater for harmlessness. The removal behavior of EfOM by UV/O3 process was characterized by synchronous fluorescence spectroscopy (SFS) integrating two-dimensional correlation (2D-COS) and principal component analysis (PCA) technology. The highest dissolved organic carbon (DOC) and ratio of UV254 and DOC (SUVA) removal efficiency reached 55.8% and 68.7% by coagulation-UV/O3 process after 60 min oxidation, respectively. Five main components of pharmaceutical tail wastewater (PTW) were identified by SFS. Spectral analysis revealed that UV/O3 was selective for the removal of different fluorescent components, especially fulvic acid-like fluorescent (FLF) component and humus-like fluorescent (HLF) component. Synchronous fluorescence/UV-visible two-dimensional correlation spectra analysis showed that the degradation of organic matter occurred sequentially in the order of HLF, FLF, microbial humus-like fluorescence component (MHLF), tryptophan-like fluorescent component (TRLF), tyrosine-like fluorescent component (TYLF). The UV/O3 process removed 95.6% of HLF, 80.0% of FLF, 56.0% of TRLF, 50.8% of MHLF and 44.4% of TYLF. Therefore, the coagulation-UV/O3 process was proven to be an attractive way to reduce the environmental risks of PTW.

Highlights

Pharmaceutical wastewater is one of the important sources for emerging pollutants such as hormones, antibiotics and non-biodegradable organic intermediates [1,2,3]
The dissolved organic carbon (DOC) concentration slightly changed during individual O3 oxidation, indicating that the O3 treatment mainly changed the structure of the organic matter by direct oxidation to form intermediate products instead of mineralizing organics into CO2 and H2 O
The 30.5% of SUVA was reduced by O3 oxidation but only 5% of DOC was removed at the same time

Summary

Introduction

Pharmaceutical wastewater is one of the important sources for emerging pollutants such as hormones, antibiotics and non-biodegradable organic intermediates [1,2,3]. The pharmaceutical residue usually entered the aquatic environment via sewage, and even low concentration can impact the drinking water and human health [4]. The pharmaceutical residue cannot be completely metabolized [2,5,6]. Some nonbiodegradable and toxic substances still exist in biologically treated effluent (pharmaceutical tail wastewater, PTW). Intensive treatment must be carried out to realize harmlessness and reduce environmental risks [7]. The biodegradability of PTW was low and not suitable for continued biological treatment [3,7,8]. The BOD5 /COD (B/C) of PTW was only close to 0.1, meaning that the

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