Removal of diclofenac from surface water by electron beam irradiation combined with a biological aerated filter

• DCF cannot be removed from surface water by biological aerated filter.
• Electron beam (EB) can effectively decompose DCF in surface water.
• Both EB and biological treatment can reduce the toxicity of treated water.
• The combined EB and BAF can eliminate DCF from surface water.

The degradation of DCF was investigated in aqueous solution by using electron beam (EB) technology. When the initial concentration was between 10 and 40 mg/L, almost 100% of the DCF was degraded at a dose of 0.5 kGy. However, only about 6.5% of DCF was mineralized even at 2 kGy according to total organic carbon (TOC) measurements. A combined process of EB and biological aerated filter (BAF) was therefore developed to enhance the treatment of DCF contaminated surface water. The effluent quality of combined process was substantially improved by EB pretreatment due to the degradation of DCF and related intermediates. Both irradiation and biological treatment reduced the toxicity of the treated water. The experimental results showed that EB is effective for removing DCF from artificial aqueous solution and real surface water.