What are the two main classes of water and how

What are the two main classes of water and how is water from a surface source, for example, from a lake, made safe to drink?

http://nursingmodules.com/wp-content/uploads/2020/02/logo-300x60.png 0 0 prince http://nursingmodules.com/wp-content/uploads/2020/02/logo-300x60.png prince2021-01-31 07:22:062021-01-31 07:22:06What are the two main classes of water and how