Treatment of organic peroxide containing wastewater and water recovery by fenton-adsorption and fenton-nanofiltration processes

Abstract

Treatment of organic peroxide-containing chemical industry wastewater by oxidation methods and recovery of water by the adsorption and nanofiltration (NP010) methods were investigated in this study. The COD and TOC removal rates were obtained as 72.8% and 58.0% in Fenton oxidation and were improved to 78.8% and 59.2% using photo-Fenton oxidation in the same conditions after 5 h of oxidation, respectively. The Fenton-treated wastewater was passed through nanofiltration to remove the organics and recover of the wastewater. The maximum COD removal efficiency of the NP010 membrane varied between 25% and 30% at all pH values. At low and high pH values (pH: 2.5 and pH: 11), as the filtration time increased, the COD removal efficiencies increased, and the highest COD removal efficiencies were obtained in the 180th and 210th minutes. The increase in the COD removal over time at low and high pH was related to the thickness of the filter layer and surface load balance accumulated on the filter surface. By Fenton oxidation coupling with adsorption, 81% of COD (decreased from 10,055 mg/L to 1906 mg/L) and 75.2% of TOC (decreased from 2597 mg/L to 645.4 mg/L) removal could be obtained, while 83.3% of COD (decreased from 9978 mg/L to 1664 mg/L) and 71.1% of TOC (decreased from 2597 mg/L to 750 mg/L) removal could be achieved using Fenton oxidation coupling with nanofiltration (P: 4 bar, pH: 11). In nanofiltration, the filtrate amounts were measured as 41.11 L/m2.h and 38.33 L/m2.h, respectively, at 4 bar and 6 bar of filter pressure and 30 min of filtration time. The increase in filtration time and filter pressure caused a decrease in the amount of the filtrate due to the rapid clogging of the filter pores.