Algal toxicity of the alternative disinfectants performic acid (PFA), peracetic acid (PAA), chlorine dioxide (ClO 2 ) and their by-products hydrogen peroxide (H 2 O 2 ) and chlorite (ClO 2 − )

Ecotoxicity Evaluation of Pure Peracetic Acid (PAA) after Eliminating Hydrogen Peroxide from Commercial PAA

“…The toxicity (EC 50 ) of pPAA towards V. fischeri was 0.84 mg/L, whilst the toxicity from cPAA towards V. fischeri was 0.42 mg/L [ 26 ]. Moreover, the toxicity (EC 50 ) of pPAA towards P. subcapitata was 2.46 mg/L, which was twice that of cPAA (1.38 mg/L) [ 27 ]. The toxicity data of pPAA obtained in this study were different than the toxicity data of cPAA reported in the literature.…”

“… Concentration profiles of pPAA in the Daphnia test medium and the algal test medium. Concentration profiles of commercial PA (cPAA) and hydrogen peroxide in a Daphnia test medium and an algal test medium were derived from Chhetri et al [ 26 , 27 ]. The fitted curve was based on the first-order degradation kinetics model presented in Equation (3).…”

Acute toxicity and risk evaluation of the CSO disinfectants performic acid, peracetic acid, chlorine dioxide and their by-products hydrogen peroxide and chlorite

“…In equation 4 t is the residual disinfectant concentration at time , 0 is the applied disinfectant dose, is the rate constant and is time. The disinfectants PFA and ClO2 are known to be unstable in an aqueous solution (Chhetri et al, 2017a), and the fast degradation of these compounds has also been observed in Daphnia testing media (Figure 3). The complete degradation of PFA in all tested concentrations was observed after 12 h, whereas for ClO2 complete degradation was not observed at the highest tested concentration (6 mg/L) after 48 h. No chlorite degradation occurred in the test media during the 48 h incubation, and only slow PAA and H2O2 degradation was observed.…”

“…The data generated in this study complement the datasets already existing in the literature for PFA, PAA and ClO2. In the following section, an environmental risk evaluation of PFA, PAA , ClO2, H2O2 and chlorite for CSO disinfection is performed based on the ecotoxicity data from this study and our previous study (Chhetri et al, 2017a) (Table 1), in which the concentrations of disinfectants and their degradation products were measured throughout the test period. In general, static ecotoxicity tests must be carried out under stable exposure conditions, i.e.…”

“…At present, only a few studies have reported data on the ecotoxicity of PFA, PAA, hydrogen peroxide, ClO2 and chlorite, and there is no consistent information regarding the toxic effect of disinfected effluents. We have recently studied the ecotoxicity of alternative disinfectants on microalgae, P. subcapitata (Chhetri et al, 2017a), but for aquatic environmental risk assessment, it is important to obtain data for organisms representing different trophic levels in the ecosystem. Thus, in order to ensure the environmental safety of disinfectants, ecotoxicity data from other organism groups is needed urgently.…”