wastewater treatment: Quick Facts

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Facts

Also Known As	sewage treatment

Photos and Videos

Diagram illustrating sewage treatment using the activated sludge process. Raw sewage passes through screens and grit chambers in primary treatment, then flows to a primary clarifier. The primary effluent enters an aeration tank for secondary treatment, where air is added and activated sludge helps break down waste. The mixture moves to a secondary clarifier, with some sludge returned to the aeration tank and excess sent for disposal. Disinfected secondary effluent is released to surface water or

aeration treatment

Diagram illustrating tertiary wastewater treatment, showing two tanks: one for filtering, where water passes through filter media to produce treated water, and one for backwashing, where air and water clean the filter using sand, gravel, and anthracite layers. Key components and flow directions are labeled.

A black plastic septic tank partially buried in an excavated pit, with surrounding dirt and exposed pipes, during installation.

A detailed diagram shows the process of sludge treatment and disposal in wastewater treatment, with labeled tanks, pipes, and equipment illustrating steps like flotation, pulping, hydrolysis, digestion, dewatering, and biogas production.

Aerial view of a wastewater treatment plant with large circular settling tanks and rectangular aeration basins surrounded by greenery and small buildings.

sedimentation tank

Aerial view of wastewater treatment basins with circular clarifiers; overlaid toilet graphic and arrow with text reading: “Where does it go?”

Does global warming affect the ocean's oxygen levels?

How is sewage and industrial wastewater reclaimed for use?

A large pile of plastic trash collected from the ocean.

How is sewage transformed into drinkable water?

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Topics

floc primary treatment plain sedimentation shallow-depth sedimentation secondary treatment tertiary treatment sedimentation tank trickling filter activated-sludge method sludge solid-waste management air pollution control hazardous-waste management Emissions trading Carbon offset sewer septic tank