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The formation of scale on surfaces in contact with water is due to many reasons as the hardness of water and its temperature. Therefore, this phenomenon of scale in water pipelines is a common and inevitable problem in the regions that exploit or use groundwater with high rigidity. The circuits fed by hot water are easily reached by hard water scaling. The deposition of encrusting curst at the level of walls in touch with water is due to many technical, economic and environmental problems. It causes a reduction in water flow and a decrease in the efficiency of heating systems.In this study, we are particularly interested in studying the phenomenon of hard water scaling caused by sanitary hot water in a tourist unit situated in the north of the seaside in the city of Agadir. First, we have evaluated the physico-chemical quality of water in use in this tourist unit. Secondly, we conducted a qualitative and quantitative analysis of the scale found in the circuits that transport sanitary hot water. Several analytical techniques were used to reach this goal namely: X-ray fluorescence (XRF) which shows that 85.50% of scale is represented by Calcium Carbonate. Whereas infrared spectrometry (IR) demonstrates the existence of the Carbonate anion CO32-. In addition, due to thermogravimetric analysis (TGA) and differential thermal analysis (DTA) we found that the endothermic event shows the decomposition of Calcium Carbonate of CaO and CO2 in the temperature range of 660 C° to 820 C°. For scanning electron microscopy (SEM), it indicates that the scale takes the form of needle-like aragonite crystals. At last, the X-ray diffraction (XRD) shows that the scale is composed essentially of Calcium Carbonate of the type aragonite.The results of the different techniques of characterisation are in concordance in the scaling of the circuits of sanitary hot water in the tourist unit under study.

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The scaling of hot water transport pipes has become one of the major problems encountered in Agadir's region, which exploits water of underground origin with very high hardness (40 F). Several methods can be used to prevent this phenomenon. Among these methods, the use of chemical inhibitors remains one of the processes to stop or retard the formation of scale deposits. In this study, we tested the inhibitor with the trade name "Aquatreat601" at different temperatures such as 30, 40 and 60 C. This inhibitor was tested at different concentrations for each temperature in order to find the efficiency concentration to prevent the precipitation of scale, which consists mainly of calcium carbonate CaCO 3 of the aragonite variety with a percentage of 88 %, and also the Mg-calcite Mg 0.06 Ca 0.94 (CO 3) with a percentage of 12 %. These results obtained by method X-ray diffraction (XRD) analysis. We carried out this study on pure calco-carbonic water, of hardness equal to 40 F, using the "LCGE" method. The quantity of inhibitor is added before the research gas is introduced. In all cases, the presence of chemical inhibitors does not alter the initial pH of the solution or the concentration of calcium (TCa) value measured before the experiment begins. The results obtained show that the ''Aquatreat 601 00 contents of 100, 180 and 300 ppm allowed total inhibition of calcium carbonate precipitation at temperatures of 30, 40 and 60 C respectively.