Optimization of Descaling Conditions of Therapy Pools in Tourist Health Center “Banja Kulaši”

Abstract

One of the problems in spa centres with thermal water is the deposition of scale on the overflow of therapeutic pools. In practice, scale is removed by washing with a solution of technical hydrochloric acid at a concentration of 10–16 w/w%. However, this process causes damage to the grout and adhesive, resulting in tile detachment. This study aimed to investigate the possibility of removing scale without significant damage, based on the chemical composition of thermal water, scale, and grout samples taken from the Health and Tourism Centre "Banja Kulaši."

Chemical analysis of the scale confirmed that it is of carbonate type (94.32% CaCO₃). The solubility of the scale and grout was tested in two ways – by immersion and by spraying with HCl solutions of varying concentrations. The immersion method showed a total solubility of the examined scale (>98%), while the spraying method aimed to simulate real cleaning conditions of therapeutic pools with different contact times. The solubility of the scale using the spraying method was also high (>92%) for contact times of 5, 10, and 15 minutes. The solubility of the grout depends on both the concentration of HCl and the contact time.