Evaluation of disinfection techniques in the treatment of advanced primary treated wastewater for Ciudad Juárez, México.
The purpose of this study was to develop and evaluate the effectiveness of alternative disinfection techniques at the bench-scale level using wastewater from Ciudad Juarez, Mexico, as model feed. This paper presents findings on the effectiveness of UV radiation, peracetic acid (PAA), chlorine dioxide (ClO2), and hypochlorous acid (HOCl) as disinfectants for advanced primary treatment (APT) plant effluent. Wastewater samples for bench-scale testing were collected from an agua negra ("black water") ditch that is part of the combined sewer system in Ciudad Juarez. Bench-scale simulations of the APT process used in Ciudad Juarez were run using a jar test apparatus and aluminum sulfate [Al2(SO4)3] as the coagulant. Jar test effluent from the bench system was used for disinfection testing. The Mexican discharge quality standard for total coliforms is 10 000/100 mL. Ultraviolet radiation met this standard at a dose of 47.5 mW-s/cm2. Ultraviolet disinfection proved reliable and effective despite the presence of suspended solids, and UV dose effectiveness expressed as a total coliforms survival ratio was best explained by a linear regression model. The ClO2 dose ranged from 10 to 20 mg/L and was only effective under ambient temperature conditions found during the winter months; PAA disinfection never met Mexican standards. Chlorine disinfection was effective at a dose range of 8 to 10 mg/L on samples collected at low temperature conditions. Since the completion of this research, Ciudad Juarez has discontinued the use of chlorine disinfection because of its high cost and ineffectiveness.
Carrasco
Leirad
L
University of Texas at El Paso, 79968, USA.
Turner
Charles D
CD
D017606:Chlorine Compounds / Q000494:pharmacology; D004202:Disinfectants / Q000737:chemistry*; D004203:Disinfection / Q000379:methods*; D004755:Enterobacteriaceae / Q000254:growth & development; D004926:Escherichia coli / Q000254:growth & development; D006801:Humans; D008800:Mexico; D010087:Oxides / Q000494:pharmacology; D010463:Peracetic Acid / Q000494:pharmacology; D012973:Sodium Hypochlorite / Q000494:pharmacology; D013997:Time Factors; D014466:Ultraviolet Rays; D018508:Water Purification / Q000379:methods* / Q000592:standards
D017606:Chlorine Compounds; D004202:Disinfectants; D010087:Oxides; C025109:chlorine dioxide; D012973:Sodium Hypochlorite; D010463:Peracetic Acid