Using treated wastewater can help conserve water since currently 66% of human usage of water is being wasted. Wastewater treatment is a way to solve water pollution problems and increase cleaner usage of water.

In 2014, in an intent to save money the city of Flint, Michigan switched from purchasing treated Lake Huron water from Detroit to treating water from the Flint River. However, since the treatment of the Flint water was inefficient many of Flint’s residents were exposed to high intakes of lead consumption. In this case, intensive and appropriate water treatment is extremely important to protect humans from consuming harmful chemicals.One of the earliest water pollution policies, the U.S. Clean Water Act (1972) set up regulations to control pollutant levels. As a result of the U.S. Clean Water Act, the wastewater treatment increased from 1992-2009 with percents of 33% to 75% which also helped safe streams increase from 33% to 60%.

The sewage treatment system consists of a primary, secondary, and tertiary process. The primary process starts off with the raw sewage from sewers going through a bar screen and then a primary setting tank where primary solids are transferred to a sludge digester. Next, the remaining wastewater is transferred to an aeration tank with an air pump. Then the water travels to the final settling tank where the rest of the solids are disposed of and advances to the tertiary process. Here, the water arrives at the gravity filters. And finally, the water gets to the Chlorine disinfection tank where the water is cleaned from bacteria and then returned to the river/lake/ocean or the now clean water can be recycled for human use. In the end, the sludge is also put in landfills, put in the ocean, or applied to croplands.

Extra outside information that is more specific on the process:

• Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface. The settled and floating materials are removed and the remaining liquid may be discharged or subjected to secondary treatment. Some sewage treatment plants that are connected to a combined sewer system have a bypass arrangement after the primary treatment unit. This means that during very heavy rainfall events, the secondary and tertiary treatment systems can be bypassed to protect them from hydraulic overloading, and the mixture of sewage and stormwater only receives primary treatment.
• Secondary treatment removes dissolved and suspended biological matter. Secondary treatment is typically performed by indigenous, water-borne micro-organisms in a managed habitat. Secondary treatment may require a separation process to remove the micro-organisms from the treated water prior to discharge or tertiary treatment.
• Tertiary treatment is sometimes defined as anything more than primary and secondary treatment in order to allow ejection into a highly sensitive or fragile ecosystem (estuaries, low-flow rivers, coral reefs,…). Treated water is disinfected chemically or physically and then returned to the ocean or recycled.

Source: https://en.wikipedia.org/wiki/Sewage_treatment

Research by: Leslie Andrade