Assessment of Bacillus subtilis spores as a possible bioindicator for evaluation of the microbicidal efficacy of radiation processing of water.

Gamma and electron-beam irradiation of Bacillus subtilis spores suspended in different types of water was studied to evaluate the inactivation of the spores and assess their possible use as a bioindicator for radiation processing. We found that the inactivation proceeded endogenously, being dose-rate-dependent and affected by oxygen. The radiation resistance of the suspended spores was found to be rather high; therefore, B.

Radiolytic decomposition of multi-class surfactants and their biotransformation products in sewage treatment plant effluents.

Electron beam irradiation (EBI), as one of the most efficient advanced oxidation processes, was applied to the treatment of sewage treatment plant (STP) effluent, with the objective of evaluating the effectiveness of radiolytic decomposition of multi-class surfactants. Target compounds, included several high-volume surfactant groups, such as alkylphenol ethoxylates (APEOs) and their biotransformation products, linear alkylbenzene sulfonates (LAS), alkyl sulfates (AS), alkylether sulfates (AES), coconut diethanol amides (CDEA), alcohol ethoxylates (AEO) and polyethylene glycols (PEGs). EBI treatment of STP effluent (total concentration of APEO-derived compounds 265mugl(-1), being APE(2)C the most abundant by-degradation products) resulted in efficient decomposition of all alkylphenolic compounds; elimination of 94% longer ethoxy chain nonylphenol ethoxylates (NPEO, n(EO)=3-15) was obtained when 3kGy were applied.

LC-MS-(MS) determination of oxidative degradation products of nonylphenol ethoxylates, carboxylates and nonylphenols in water.

A commercial blend of nonylphenol ethoxylates (NPEOs) was chosen as representative for non-ionic polyethoxylated surfactants to study the oxidative degradation of this class of surfactants in water using ozonation as well as electron beam irradiation with and without the addition of ozone as treatment processes. The electron beam irradiation processes applied represent so-called Advanced Oxidation Processes (AOPs); the combined ozone/electron beam irradiation is, moreover, the most powerful AOP which can be applied in aqueous systems. It was found that both ozonation and the two AOPs applied were able to decompose not only the NPEOs but also the polyethyleneglycoles (PEGs) formed as by-products from NPEO degradation to residual concentrations below the limit of detection.

Bacteriophages as viral indicators for radiation processing of water: a chemical approach.

Inactivation of the bacteriophages PHI X 174 (somatic coliphage), MS2 (F-specific coliphage) and B40-8 (phage infecting Bacteroides fragilis) suspended in tap water was studied applying gamma and electron beam irradiation as well. PHI X 174 phage was found to be a suitable viral indicator for water disinfection by means of ionizing radiation. The nutrient broths introduced simultaneously with the bacteriophages into the water when it is spiked with the phages for the experiments did not significantly change the scavenging capacity of the water matrix.

Inactivation of bacteriophages in water by means of non-ionizing (UV-253.7 nm) and ionizing (gamma) radiation: a comparative approach.

Thc inactivation behaviour of the bacteriophages PHI X 174 (ssDNA virus). MS2 (ssRNA virus) and B40-8 (dsDNA) toward non-ionizing (UV-253.7 nm) as well as to ionizing radiation (gamma radiation) was studied in order to evaluate their potential as viral indicators for water disinfection by irradiation.