The process of clean sewage water is that removes the majority of the contaminants from wastewater
 or sewage and produces both a liquid effluent suitable for disposal to the natural environment and a
 sludge. To be effective, sewage water must be conveyed to a treatment plant by appropriate pipes
and infrastructure, the process must be subject to regulation and controls. Some wastewaters require
different and specialized treatment methods. At the simplest level, treatment of sewage and most
wastewaters is carried out through separation of solids from liquids, usually by settlement. By
progressively converting dissolved material into solids, usually a biological floc which is then settled
out, an effluent stream of increasing purity is produced.
In developing countries,from 2006, waterborne diseases are estimated to cause 1.8 million deaths each
year. These deaths are attributable to inadequate public sanitation systems and it is clear that proper
sewerage (or other options as small-scale wastewater treatment) need to be installed.[1]
Appropriate technology options in water treatment include both community-scale and household-scale
point-of-use (POU) designs.[2] Military surplus water treatment units like the ERDLator are still seen in
developing countries. Newer military style Reverse Osmosis Water Purification Units (ROWPU) are portable,
self-contained water treatment plants are becoming more available for public use. [3]
In order for the decrease of waterborne diseases to have long term effects, water treatment programs
implemented by research and development groups in developing countries must be sustainable by its
own residents. This can ensure the efficiency of such programs after the departure of the research team
as monitoring is difficult because of the remoteness of many locations.