Wastewater Treatment Process
At our two wastewater treatment plants, raw sewage undergoes a transformation using physical, biological, and chemical treatment processes. This transformation allows treated wastewater (aka, effluent) to be returned safely to the environment, safeguarding public health and protecting fish and wildlife.
Step Number 1: Physical Treatment
Physical treatment, like bar screens, remove large debris from sewage, including "flushable" wipes (please don't flush these, by the way) and the toys your two-year-old puts in the garbage disposal. We also remove grit and grease, like those coffee grinds or bacon grease you should have thrown in the trash.
Keep in mind, the less you put down the drain, the easier it is for us to treat the wastewater. The only thing that should enter the sewer system is human waste and toilet paper. Don't use your toilet as a trash can or pour harmful chemicals down the sink. For information about how to safely dispose of trash and household hazardous waste, visit our Solid Waste District.
Step Number 2: Biological Treatment
Biological treatment is where we use helpful bacteria to break down organic matter. These bacteria reproduce and consume the solids (e.g., food particles, human waste) in wastewater. We call them our "bugs."
Step Number 3: Chemical Treatment
Chemical treatment, or disinfection, is where we add chlorine to kill pathogens and harmful microorganisms in wastewater. Disinfection helps to safeguard public health and prevent the spread of waterborne diseases and illnesses, which are still very common around the world. About 1,800 children under the age of five die every day from diarrhoeal diseases, because they lack access to clean water and adequate sanitation, according to UNICEF.
Step Number 4: Safe Discharge
Chlorine can harm fish or wildlife, so we add sodium bisulfite to neutralize it before the treated wastewater is discharged into local waterways. Treated wastewater is called "effluent." The effluent that we discharge from our wastewater treatment plants is safe for fish and wildlife, and also helps to maintain adequate water levels in local waterways, especially during the hot summer months