Water School

How is wastewater cleaned?

How is wastewater cleaned?

While exact methods can vary, here’s a general breakdown of the municipal wastewater treatment process:

  • When wastewater leaves a home or business, it is transported through municipal collector pipelines usually by the force of gravity, to a wastewater treatment plant. If gravity flow is not available all the way, then a lift station may pump the wastewater up to a level where gravity flow can again take place.
  • As wastewater enters the treatment plant, it is screened to remove non-sewage items such as rags, clothing, toothbrushes, or any other solids that might damage or clog the equipment. This material is sent to landfills.
  • The sewage then moves into grit settling tanks where grit is removed to a landfill.
  • Next, the wastewater is sent to aeration tanks, which move the sewage to expose it to oxygen and naturally occurring bacteria.  The bacteria break organics down into carbon dioxide and water and form “floc” which helps settle the remaining inorganic materials.
  • The wastewater then enters another settling tank. Here, the “floc” settles to the bottom and is pumped out as “biosolids”. The biosolids enter either the large “digester” tanks or are returned to the treatment process to reseed the aeration.
  • In the digester, bacteria further break down or “digest” the organic material. This part of the process takes 20 to 30 days. This digested material, its volume and odor reduced and harmful microorganisms gone, is taken either to a landfill or sometimes further processed for use as a soil conditioner.
  • From the settling tanks, the wastewater is typically disinfected by chlorine (gas or liquid) or by the ultraviolet light before being discharged to the receiving stream.

The Authority owns and operates one treatment system, the Temple-Belton Regional Sewerage System. The Authority also operates wastewater systems for the cities of Hutto, Clute/ Ridgewood, Georgetown, Sugar Land, Liberty Hill, Lee County Fresh Water Supply District No. 1, and the Brushy Creek Regional wastewater system which serves the City’s of Round Rock, Cedar Park, Austin and the Fern Bluff and Brushy Creek MUDs.




The information provided on this site is intended as background on water within the Brazos River basin. There should be no expectation that this information is all encompassing, complete or in any way examines every aspect of this very complex natural resource.

If you have questions about a post or would like additional information, please contact us or call 888-922-6272.