Insight into the characteristics, removal, and toxicity of effluent organic matter from a pharmaceutical wastewater treatment plant during catalytic ozonation

Shuhan Wen,Weiqi Li,Bing Wu,Kan Li,Ke Xu,Haidong Hu,Lin Chen,Hongqiang Ren

doi:10.1038/s41598-018-27921-0

Abstract

Changes in the characteristics, removal efficiency, and toxicity of pharmaceutical effluent organic matter (EfOM) after catalytic ozonation were investigated in this study. After a 90-min treatment with a catalytic ozonation process (COP) in the presence of MnO2 ceramsite, the total organic carbon (TOC), UV254, colority, protein, and humic acid removal rates were 13.24%, 60.83%, 85.42%, 29.36% and 74.19%, respectively. The polysaccharide content increased by 12.73 mg/L during the COP for reaction times between 0 and ~50 min and decreased by 6.97 mg/L between 50 and ~90 min. Furthermore, 64.44% of the total colority was detected in the hydrophobic organic matter (HOM) fraction, and after the COP, and 88.69% of the colority in the HOM was eliminated. Meanwhile, only 59.18% of the colority in the hydrophilic organic matter (HIM) fraction was removed. GC-MS analysis showed that 38 organic pollutant species were completely removed, 8 were partially removed, and 7 were generated. After 90 min of COP treatment, the pharmaceutical EfOM toxicity was effectively reduced based on the higher incubation and lower mortality rates.

Highlights

With the rapid growth of pharmaceutical needs, large quantities of wastewater containing products, raw materials, solvents and detergents from complex manufacturing processes are generated[1]
The results indicate that the sole ozonation process (SOP) is almost ineffective for total organic carbon (TOC) removal, but it is quite effective in the destruction of aromatic compounds and double-bond systems
There is a strong correlation between the reduction of UV254 and the production of ·OH during ozonation[21], which indicates that more ·OH is generated during the catalytic ozonation process (COP)

Summary

Introduction

With the rapid growth of pharmaceutical needs, large quantities of wastewater containing products, raw materials, solvents and detergents from complex manufacturing processes are generated[1]. Advanced chemical oxidation processes (AOPs) have attracted much attention for the advanced treatment of industrial wastewater, such as the base process of O3, H2O2, Peroxone, sulfate radical and photocatalytic[5,6,7,8,9] Among these AOPs, the catalytic ozonation process (COP) has a strong ability to degrade refractory organic pollutants and effectively decolor water via hydroxyl radicals (·OH)[10,11] and broad application potential for wastewater treatment. Porous materials with large surface areas and abundant porous structures have been widely used as metal oxide carriers because of their good performance for increasing the active surface area and adsorption capacity[15,16] Among these carriers, attapulgite (ATP) is a type of natural, hydrated magnesium silicate mineral with unique pore channels, a large surface area, a high adsorption capacity, and water-insolubility[17,18,19]. The toxicity of the pharmaceutical EfOM after the COP treatment was assessed to determine its potential risks, as mentioned earlier

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Conclusion