Resistance and inactivation kinetics of bacterial strains isolated from the non-chlorinated and chlorinated effluents of a WWTP.
The microbiological quality of water from a wastewater treatment plant that uses sodium hypochlorite as a disinfectant was assessed. Mesophilic aerobic bacteria were not removed efficiently. This fact allowed for the isolation of several bacterial strains from the effluents. Molecular identification indicated that the strains were related to Aeromonas hydrophila, Escherichia coli (three strains), Enterobacter cloacae, Kluyvera cryocrescens (three strains), Kluyvera intermedia, Citrobacter freundii (two strains), Bacillus sp. and Enterobacter sp. The first five strains, which were isolated from the non-chlorinated effluent, were used to test resistance to chlorine disinfection using three sets of variables: disinfectant concentration (8, 20 and 30 mg·L(-1)), contact time (0, 15 and 30 min) and water temperature (20, 25 and 30 °C). The results demonstrated that the strains have independent responses to experimental conditions and that the most efficient treatment was an 8 mg·L(-1) dose of disinfectant at a temperature of 20 °C for 30 min. The other eight strains, which were isolated from the chlorinated effluent, were used to analyze inactivation kinetics using the disinfectant at a dose of 15 mg·L(-1) with various retention times (0, 10, 20, 30, 60 and 90 min). The results indicated that during the inactivation process, there was no relationship between removal percentage and retention time and that the strains have no common response to the treatments.
Instituto de Ciencias Básicas e Ingeniería, Área Académica de Química, Universidad Autónoma del Estado de Hidalgo, Carr, Pachuca-Tulancingo km. 4.5 s/n, Ciudad del Conocimiento, Mineral de la Reforma, Hidalgo, C.P. 42184, Mexico. smhjunio@gmail.com
Sylvia
S
Martínez-Hernández
Gabriela A
GA
Vázquez-Rodríguez
Rosa I
RI
Beltrán-Hernández
Francisco
F
Prieto-García
José M
JM
Miranda-López
Carlos M
CM
Franco-Abuín
Alejandro
A
Álvarez-Hernández
Ulises
U
Iturbe
Claudia
C
Coronel-Olivares
D016980:Aeromonas hydrophila / Q000187:drug effects / Q000302:isolation & purification; D002713:Chlorine / Q000737:chemistry / Q000494:pharmacology*; D004202:Disinfectants / Q000494:pharmacology; D004203:Disinfection; D016972:Enterobacter cloacae / Q000187:drug effects / Q000302:isolation & purification; D004926:Escherichia coli / Q000187:drug effects / Q000302:isolation & purification; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification*; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000302:isolation & purification*; D054879:Halogenation; D044086:Kluyvera / Q000187:drug effects / Q000302:isolation & purification; D012973:Sodium Hypochlorite; D062065:Wastewater / Q000382:microbiology*; D014871:Water Microbiology
D002713:Chlorine; D004202:Disinfectants; D012973:Sodium Hypochlorite; D062065:Wastewater