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The main aim of this paper is to present a method for risk analysis using Bayesian process. The proposed method made it possible to estimate risk associated with the possibility of partial or total loss of the ability of water supply system operation. The paper proposes to consider two types of risk: the first type, associated with the possibility of interruptions in water supply and the second type, associated with the possibility of tap water contamination. 

In this work, three samples of nitrogen-doped TiO₂ prepared at different calcination temperatures (400, 450 and 500 °C) were applied for the adsorption of Direct Black 38. Kinetic studies about the adsorption of Direct Black 38 on nitrogen-doped TiO₂ were performed under different initial dye concentrations
(75-175 mg l^-1). Pseudo-first and pseudo-second order models were fitted with the experimental data. The results revealed that nitrogen-doped TiO₂ synthesized at 400 °C presented the more adequate characteristics for adsorption purposes, such as specific surface area of 151 m² g^-1. The adsorption kinetics agreed with the pseudo-second order model, at initial dye concentrations from 75 to 175 mg l^-1. The maximum adsorption capacity predicted by the pseudo-second order model was 138.3 mg g^-1, and was obtained using nitrogen-doped TiO₂ synthesized at 400 °C. In summary, these results revealed that nitrogen-doped TiO₂ is a good material for the removal Direct Black 38 from aqueous solutions by adsorption. 

Several adsorbents have been tried out by researchers to remove different pollutants from wastewater. However, the adverse effect of these biosorbents on the treated water and the possibility of leaching new pollutants to the treated water have not been investigated.  A batch technique was employed to study this phenomenon. Three agricultural wastes namely sawdust, dates stones and palm fibers were investigated. The possible leaching of total dissolved solids (TDS) and organic compounds in the form of chemical oxygen demand (COD) from these substances to water were investigated. The effect of water pH and particle size of these biosorbents on the extent of the leaching process was studied. The results indicate high release of both TDS and COD for the three biosorbents. A COD value as high as 230 mg l^-1 was obtained, while the highest TDS leached was 29 mg l^-1. DS was found to have the highest leaching ability, followed by SD and PF. The highest leaching was obtained at high pH and small particle size of the adsorbent.

The natural regeneration of Scots pine stands at the Sarakatsana location in the Pieria Mountains improved considerably after the removal of the dense ground vegetation followed mechanical soil scarification. The experimental design consisted of replications on scarified and non-scarified soil. The results four years after the experiment was set up showed that regeneration reached 59 seedlings m-2 in scarified and 7 seedlings m-2 in non-scarified soil. Soil scarification seems to have had a positive effect on the emergence and survival of naturally regenerated Scots pine. The negligible number of dead seedlings in the first two measurements could be due to the favourable site and/or good climatic conditions. Although the mother stand appears to be in a critical condition due to age and increased necrosis as a result of fungal attacks, there is still considerable potential for regeneration in terms of fructification and seed production. The study findings indicate that there can be new growth of Scots pine forest with the shelterwood method of natural regeneration in combination with soil scarification.