The design of the wastewater treatment plants falls into another area of civil engineering called water resources engineering.

The actual treatment of the wastewater is part of environmental engineering.

When the wastewater first enters the plant rags, sticks, cans, toys and other similar objects are removed by mechanical rakes. From here the wastewater flows to the aerated grit chamber where smaller inorganic objects such as sand and gravel are removed.

The inorganic materials removed are disposed of in a sanitary landfill.

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The primary clarifier is a large, open-air tank where heavier solids settle out by gravity. The settled solids are called primary sludge. The sludge is scraped into a pit and then pumped into the gravity thickener and eventually to the anaerobic digesters. The floating scum and grease on the surface of the clarifier is pumped into the anaerobic digesters. Remaining wastewater flows to the aeration tanks and bioreators for secondary treatment.

Want to know more about the wastewater treatment process?

Primary Treatment, Secondary Treatment, Sludge Handling