Dear Peter, water ...

Dear Peter,

water reclamation for reuse is just driven by water scarcity, nobody is reclaiming water for fun or for profit.

Regarding your question, treatment methods differ according to the intended use. Water quality requirements for agricultural use are less stringent than for indirect potable use (aquifer recharge). Reclamation for direct potable use is not a common practice, and in such a case the treatment would be the same that for drinking water.

You will find pretty interesting reference documents here:

http://ec.europa.eu/environment/water/reuse.htm

or refer to the experience in California.