Evaluation of groundwater hardness removal using activated clinoptilolite.

Current study aimed to investigate modified natural clinoptilolite for removal of calcium and magnesium from the groundwater. Feasibility of clinoptilolite for groundwater hardness removal in production and operation was verified by static adsorption experiment and the experiment of fixed bed and degasification column. Subsequently, the main parameters for groundwater treatment using clinoptilolite were also explored. Results show that in the process of clinoptilolite in adsorption is dominant reaction process. The adsorption equilibrium time was unchanged when the hardness of raw water changes from 450 to 550 mg/L. With respect to comparative analysis of price and performance, NaCl found to be the most suitable clinoptilolite regenerated agent. The adsorption efficiency was high when the residence time was 20-25 min in the pilot experiments. The reaction mechanism was mainly substitution reaction according to ion equilibrium, and the treatment capacity of the degasifier combined with the fixed bed was 20% higher than that of with only fixed bed.