Inactivation of Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli present in treated urban wastewater by coagulation-flocculation and photo-Fenton processes

The purpose of the current study is to evaluate the inactivation of three different kinds of bacteria usually present in municipal wastewater treatment effluents ( Enterococcus faecalis , Pseudomonas aeruginosa and Escherichia coli ) using a coagulation-flocculation-decantation (CFD) process combined with photo-Fenton treatment at pH 5. Different concentrations of Fe 3+ -H 2 O 2 (0.4/25, 5/25 and 15/25 mg L −1 ), and H 2 O 2 (25 mg L −1 ) were evaluated for 210 minutes under artificial solar irradiation in a solar chamber ATLAS SUNTEST CPS+. The results were compared applying the CFD process before or after the disinfection treatment. The results of the bacteria inactivation show that the highest rate was observed using CFD-photo-Fenton treatment with 15 mg L −1 of Fe 3+ and 25 mg L −1 of H 2 O 2 , obtaining the total inactivation of Pseudomonas sp., a 5.64-log inactivation of Enterococcus sp. and a 4.61-log inactivation of E. coli . In addition, turbidity and suspended solids decreased more than 90% with the combined treatments. The treated wastewater samples could be reused in urban, agricultural, industrial, recreational and environmental uses according to current Spanish legislation (RD 1620/2007). This work presents a proposal for wastewater reclamation combining a coagulation-flocculation process and a photo-Fenton reaction at pH 5 for the inactivation of faecal indicator bacteria.