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Disinfection of an Advanced Primary Effluent with Peracetic Acid and Ultraviolet Combined Treatment: A Continuous‐Flow Pilot Plant Study
Author(s) -
González Abelardo,
Gehr Ronald,
Vaca Mabel,
López Raymundo
Publication year - 2012
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143012x13347678384765
Subject(s) - peracetic acid , effluent , pilot plant , continuous flow , primary (astronomy) , waste management , pulp and paper industry , water treatment , chemistry , environmental science , ultraviolet radiation , environmental engineering , engineering , radiochemistry , hydrogen peroxide , organic chemistry , biochemical engineering , physics , astronomy
Disinfection of an advanced primary effluent using a continuous‐flow combined peracetic acid/ultraviolet (PAA/UV) radiation system was evaluated. The purpose was to determine whether the maximum microbial content, established under Mexican standards for treated wastewaters meant for reuse—less than 240 most probable number fecal coliforms (FC)/100 mL—could be feasibly accomplished using either disinfectant individually, or the combined PAA/UV system. This meant achieving reduction of up to 5 logs, considering initial concentrations of 6.4·10 +6 to 5.8·10 +7 colony forming units/100 mL. During the tests performed under these experiments, total coliforms (TC) were counted because FC, at the most, will be equal to TC. Peracetic acid disinfection achieved less than 1.5 logs TC reduction when the C t ·t product was less than 2.26 mg·minimum (min)/L; 3.8 logs for C t ·t 4.40 mg·min/L; and 5.9 logs for C t ·t 24.2 mg·min/L. In continuous‐flow UV irradiation tests, at a low‐operating flow (21 L/min; conditions which produced an average UV fluence of 13.0 mJ/cm 2 ), the highest TC reduction was close to 2.5 logs. The only condition that produced a disinfection efficiency of approximately 5 logs, when both disinfection agents were used together, was the combined process dosing 30 mg PAA/L at a pilot plant flow of 21 L/min and contact time of 10 minutes to attain an average C t ·t product of 24.2 mg·min/L and an average UV fluence of 13 mJ/cm 2 . There was no conclusive evidence of a synergistic effect when both disinfectants were employed in combination as compared to the individual effects achieved when used separately, but this does not take into account the nonlinearity (tailing‐off) of the dose‐response curve.