To best answer your ...
Published by Allan McElroy, Chartered Process Engineer
To best answer your question, more information is need.
What else is in the water. What is the water to be used for. What are the constraints on the product and waste water streams. What is the desired product flow rate and water quality. Are there other constraints. Such as discharge limits, supply/access issues for the site (availability/reliability of power supply, access to site).
Depending on the scale of your problem and the existing/ available infrastructure, then ion exchange (chemical, electrochemical), cold Lime softening, warm lime softening, EDR or other process could be your best available solution.