Climate changes and effects on river flow in the Romanian Carpathians

The paper highlights some relevant changes detected in Romania, namely in the Carpathian area, and related impacts on streamflow. It focuses on Valea Cerbului River catchment, a small mountainous watershed (extended over 26 km2, in the eastern extremity of the Southern Carpathians), where observed and projected changes of the river flow were presented based on frequency and trend analysis of recorded discharges and on hydrological modeling. As observed changes (between 1950-2010), general upward significant trends in the variability of the average discharge were detected, for both annual and monthly discharges (mostly in October, January and July). The projected changes were estimated by the WaSiM-Eth hydrological model for 2035-2065 period, compared to the reference period 1961-1991 (using climatic data on the A1B scenario obtained within the project ENSEMBLE). The results showed the increase of high flows in the cold season (December − April) and a significant decrease in discharges during the warm season (June − November, mainly in August − September)

Modelling and automation of the process of phosphate ion removal from waste waters

Phosphate removal from waste waters has become an environmental necessity, since these phosphates stimulate the growth of aquatic plants and planktons and contribute to the eutrophication process in general. The physicochemical methods of phosphate ion removal are the most effective and reliable. This paper presents studies on the process of phosphate ion removal from waste waters resulting from the fertiliser industry’s use of the method of co-precipitation with iron salts and with calcium hydroxide as the neutralizing agent. The optimal process conditions were established as those that allow achievement of a maximum degree of separation of the phosphate ions. The precipitate resulting from the co-precipitation process was analysed for chemical composition and establishment of thermal and structural stability, and the aim was also to establish in which form the phosphate ions in the formed precipitate can be found. Based on these considerations, the experimental data obtained in the process of phosphate ion removal from waste waters were analysed mathematically and the equations for the dependence of the degree of phosphate separation and residual concentration versus the main parameters of the process were formulated. In this paper an automated scheme for the phosphate ion removal from waste waters by co-precipitation is presented