Water may be treated differently in different regions. Drinking water supplies in Asia are among the least safe in the world. The drinking water is contaminated and causing sickness and disease from waterborne germs. 

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Appropriate treatment to remove the disease-causing agents is crucial. Today, most households have the water filter system installed. However, not all people in Sulu is affording to have the filter system. 

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A sewage system or wastewater collection system is a network of pipes, pumping stations and equipment that convey sewage from its points of origin to a point of treatment and disposal. 

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There are three levels of wastewater treatment :

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Primary Treatment 

Removes about 60% of total suspended solids and about 35% of biochemical oxygen demand (BOD) 

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Secondary Treatment

Removes more than 85% of total solids and BOD must be removed/when dissolved nitrate and phosphate levels must be reduced

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Tertiary Treatment

Removes more than 99% of all impurities from sewage, producing drinking water quality 

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