Erich, I agree with Bruce`s ...
Published by Owen Stevens, Fiber Technology Corporation - VP Sales & Marketing
Erich, I agree with Bruce`s answer below, to many variables for a definitive answer. Depending on the quantity required, one of the most effective basic solutions is an SSF (slow sand filter) which is easy to construct and maintain. It combines many elements of more advanced methods such as biological treatment and can render water safe to drink.