To view pictures of the bar screens before installation, click on the image of the Raw Wastewater Pump Building on the right. Two Primary Settling Basins allow smaller particles to settle from wastewater by gravity. This primary wastewater flows out to the next stage of treatment. A surface skimmer collects scum or grease floating on top of the basins. 1 Two Aeration Basins supply large amounts of air to the mixture of primary wastewater and helpful bacteria and the other microorganisms that consume the harmful organic matter.
Adequate oxygen is supplied to support the biological process at a very active level.
The wastewater passes through two more WTU's before treatment is completed. For more information about the City of Columbia's constructed wetlands treatment system , click on the image of cattails on the right. The final effluent is monitored daily. The grit is disposed of in the City landfill. The primary sludge continues on to the gravity Sludge Thickener where the solids are concentrated and pumped to the anaerobic digesters.