[en] A radiation method of disinfection of sewage sludge and excessive active silt with the use of electron accelerator is developed to produce agricultural fertilizers. The method includes the following stages: the raw material preparation (sludge and silt) in any ratios, irradiation at the electron accelerator, filtration of disinfected and sterilized sludge, thermal drying and packaging of ready products

[en] The ionizing radiation treatment of sewage and redundant activated sludges at doses ranging from 5 to 10 kGy was shown to decrease the specific resistance to filtration, the zeta-potential of colloidal particles, the bound water content of sewage sludge and to increase the amount of highly molecular substances of filtrate. The dependence of viscosity on concentration and temperature obtained in the radiolysis of gelatin solutions acting as model system allow us to suggest that the straightening out of the dissolved protein molecules and their flocculating properties may be one of the reasons of the improved filtrability of irradiated sludges. (author)

[en] Short note

No abstract available

[en] Quantitative data on the ⁶⁰Co-radiation and accelerated electrons action are obtained at doses ranging from 1 to 40 j/g. The ionizing radiation treatment decreases the specific resistance to filtration (SRF), the xi-potential (xi- p) values of raw and activated sludges and increases free water content of raw sludge almost by a factor of 2. The plots of xi- p and SRF values vs radiation doses have a similar trend. The data obtained show that the sludges dewatering improvement is due to a decrease in the stability of colloid systems. Low doses are more effective in this respect than higher ones. Besides, partial dissolving of solid phase was observed (increase in COD and in the weight of filtrate dry residue) and an enhancement of colloid content. The latter was due mainly to high molecular compound formation. The results presented confirm experimentally the dewatering improvement mechanism of sludges which suggests colloid stability decrease effected by high molecular flocculants formed in the radiation induced oxidation of organic polllutants. At higher doses the polymeric flocculants are formed in excess, this aggravates sludge dewatering and consequently lowers the radiation efficiency at higher doses. (author)

No abstract available

[en] The mechanism of γ-radiolysis of aqueous solutions of substituted naphthalene NphX, where X-α-CH₃, α-NH₂, α-NO₂, β-OCH₃, β-CH₃, β-Cl has been investigated. The concentration of substituted naphthalene before and after irradiation as well as concentration of formed mononaphthols has been determined chromatographically. Preliminarily by means of mass-spectrometry the process of naphthalene oxidation by Fenton reagent (H₂O₂+Fe⁺⁺) in H₂¹⁸O is studied. It is shown that naphthalene oxidation by hydroxyl radicals generated by the H₂O₂+Fe⁺⁺ system occurs according to the mechanism comprising acid fragmentation with transition into dihydroxynaphthalene only of oxygen from water as well as entering into the formed compound of the second light hydroxyl group from the oxidizer. It has been found that radiation chemical yields of substituted napthalene consumption are considerably higher than the yields of α and β mononaphthols formation and the yields of α naphthols are higher than those of β-naphthols. Low mononaphthol yields are due to their fast oxidation up to trihydroxynaphthalenes and other radiolysis products