Almost 70% of the earth's surface is water, but most of that is ocean. By volume, only 3% of all water on this earth is fresh-water, and most of this is largely unavailable.

Water treatment processes have been upgraded and enhanced with time. In this section we discuss the contemporary (integrated) and conventional approaches towards water treatment.

Wastewater in the simplest terms is used water that may come out of homes (water from sinks, showers, bathtubs etc.), industries, businesses, public utilities and many other sources.

There are two approaches to wastewater treatment; the conventional approach and the new integrated approach.