Comparison of the options of systems for adjusting the salt composition of water from underground sources

Summary

Underground water sources with a high content of hardness salts are often used for drinking water supply. To achieve drinking water quality reducing its hardness is required. Known methods of softening result in the formation of a significant amount of liquid and solid wastes, i. e. mineralized wastewater or sludge that cannot be disposed of. Chemical water softening in clarifiers is used quite rarely owing to the difficulty of preparing chemicals, maintaining the constant required water temperature, and the complexity and maintenance of the equipment. In the 1990s, the technology of chemical softening in intensified reactors (vortex and blanket) was developed that gained widespread use in drinking water supply. Such units are quite frequently used in Europe and USA. At present Mediana-Filter Research and Production Company JSC is taking on the task of designing and testing reactors of this type. They have a high specific output of 50–100 m³/(m²·h), and their maintenance is much easier compared to clarifiers. The capacity of such plants reaches thousands of cubic meters per hour. Their main advantage is the elimination of liquid discharges and generation of solid wastes that can subject to utilization, while the yield of clean water is about 100%.

Key words

potable water , reverse osmosis , suspended layer , pilot plant , chemical softening , water softening , contact media , calcic pellets , fluidized bed , intensified reactor , dynamic softening system , sodium cycle