Assessment of Corrosion and Scaling Potential of Thermal Water in the Northern Algerian Sahara Using Hydrogeochemical Analysis and Stability Indices

Abstract

In the Algerian Sahara, the management of thermal water quality is confronted with substantial challenges associated with corrosion and scaling issues which directly affect the durability of infrastructure, incur high economic costs, and can compromise the sanitary quality of water supplies. This research investigates thermal waters' corrosive and scaling tendencies in the Hassi Messaoud region, a vital area in the Northern Algerian Sahara. The investigation relies on the analysis of samples obtained in 2022 from thirty-one (31) thermal water boreholes, exhibiting an average temperature of 50.17°C. The approach involves evaluating four key reference indices: Langelier Saturation Index (LSI), Ryznar Stability Index (RI), Larson-Skold Index (LS), and Puckorius Index (PI). The results reveal that the total samples lie in the category indicating the supersaturated state with scaling forming tendency for both LSI and PI indices. In addition, 48.4 % of the samples point toward scaling water and their RI lies between the limit of 5.56–6,2 while the RI value of the 51.6% of samples is found to have no effect, neither corrosive nor scale behavior. With regard to the chloride sulfate effect, it has been observed that whole samples exhibit an LS value greater than 1.2, thus approving the corrosiveness of water towards the distribution system. The majority of the indices reveal significant scale potential trends in thermal water samples toward carbonates calcium and the corrosive effect concerning sulfate and chloride, suggesting that future water quality and distribution systems may become even worse. Therefore, it is crucial to consistently monitor the stability of this water at various locations within water distribution systems.