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Biological Wastewater Treatment

Wastewater treatemnt processes remove contaminants from the water before it is discharged into rivers, lakes and streams.  The first step, primary or mechanical treatment, removes large, suspended and floating solids from raw sewage. 

​The next step is called secondary or biological treatement.  Biological wastewater treatment confines high concentrations of naturally occuring bacteria in treatment tanks.  These bacteria, along with protozoa and other microbes, form activated sludge.  When the activated sludge bacteria "eat" small organic carbon molecules, the wastewater is cleansed.  Biological treatment is widely used because it is more cost effective than other types of treatment processes, such as chemical oxidation or thermal oxidation.  

Evoqua offers a wide range of industry-leading biological processes.  The Orbal​​® system​ is the most energy efficient, lowest maintenance and safest oxidation ditch available.  BioMag®​ ballasted clarification systems​ use the world's fastest proven settling clarification technology for biological floc.  The Captivator® system​ is the only treatment technology that enables net-zero energy demand without chemicals or microscreens.

Read a recent Elkton, Md., case study​ to learn how the Orbal system achieved total nitrogen removal greater than 95 percent while reducing energy consumption by 40 percent.  

Click on the tiles below to explore Evoqua's biological treatment solutions.