Avaliação de métodos para desinfecção de água, empregando cloro, ácido peracético, ozônio e o processo de desinfecção combinado ozônio/cloro / Methods evaluation for water disinfection using chlorine, peracetic acid, ozone and the ozone/chlorine combined disinfection process

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

This is the result of a comparative disinfection study, performed in similar experimental conditions, among hypochlorite of sodium, peracetic acid, ozone and the ozone/chlorine sequential disinfection process for waters of study with low color (<5 uH) and high color (>100 uH) features. The disinfectants performance was evaluated according to the inactivation of three indicators microorganisms: Escherichia coli ATCC 11229, coliphages and Clostridium perfringens ATCC 13124. The applied concentrations of chlorine (CL IND.2), peracetic acid and ozone (O IND.3) were of 2,0; 3,0; 4,0 and 5,0 mg/L. The sequential disinfection consisted of the following concentrations combinations in mg/L: 2,0 O IND.3/ 2,0 CL IND.2; 3,0 O IND.3/ 2,0 CL IND.2; 5,0 O IND.3/ 2,0 CL IND.2and 2,0 O IND.3/ 5,0 CL IND.2. The different times of contact employed were of 5, 10, 15 and 20 minutes, as for the single test, as for the sequential stage. The free chlorine applied was quickly transformed into combined chlorine forms, in the first 5 minutes of contact, for all the dosages applied, reducing its disinfectant action. The disinfection tests results with peracetic acid indicated an effective reduction of the indicators microorganisms employed, even in the presence of a high concentration of organic matters, deriving from the culture medium. The ozone was considered effective for the inactivation of all the three indicators microorganisms, presenting better results than the other disinfectants for the phages inactivation. In the stage of the sequential disinfection, the inactivations of E. coli, coliphages and C. perfringens were remarkably superior to the inactivations obtained with just ozone and chlorine. It occurred synergism to E. coli and phages for all dosages and times of contact employed. Such a phenomenon was not observed in relation to the sporulated bacteria C. perfringens, for all the combinations of ozone and chlorine tested

ASSUNTO(S)

indicators microorganisms ácido peracético ozônio ozone combined disinfection desinfecção combinada peracetic acid chlorine microrganismos indicadores cloro

ACESSO AO ARTIGO

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