What Happens After the Flush?
“Outta sight, outta mind” is the attitude most of us have when flushing a toilet. We don’t want to think about it or ask about it, but someone has to answer it. So what really happens after you flush?
For starters, all the dirty water leaving your residence is called “wastewater”, which eventually ends up somewhere, right? Well, that “somewhere” is through a pipe that leads out of your residence and ties into the local sewer system. That pipe connects to another pipe where it connects to an even larger pipe that serves the neighborhood - that’s a lot of pipes!
All pipes are most commonly made of concrete, clay tile, and plastic. All sewage systems are designed so that gravity does most of the work of getting wastewater from your residence to your local treatment plant.
Once it reaches the wastewater treatment plant, the water passes through fairly coarse metal screens that filter out various debris, such as paper, branches, and rags. The water then passes into a grit chamber where dirt, sand, and inorganic solids have a chance to just settle. And don’t worry - the bigger chunks of stuff collected are normally shipped off to the local landfill.
Wastewater then moves out of the grit chamber very slowly through primary clarification tanks. Now this is where gravity steps its game up: some of the heavier junk sinks to the bottom, creating what’s called ‘sludge’. The stuff that floats to the top, that’s called scum.
Water spends a couple of hours in the clarification tank where 50-70% of suspended toxic materials and solids will separate. Machines skim these results, and the sludge and scum is sent to digestor tanks where microorganisms feed on it. Eventually breaking down to methane gas, water, and carbon dioxide.
Once the water is out of the primary clarification tanks, wastewater goes through its second round of treatment. This method is most commonly known as “activated” sludge process.
Here, the water flows into tanks where oxygen is added. This promotes the growth of the bacteria that feeds on the organic waste that’s still in the water. Over about eight hours, masses called “floc” are generated.
The water then passes through other clarification tanks where the floc is removed. By the time a secondary clarification treatment is complete, about 90% of pollutants in water has been removed.
The last step of the process is called, “tertiary treatment;” which includes addition of certain chemicals that helps settle some remaining floc and kill harmful bacteria. The water then passes through filters where all remaining organic and inorganic matter is moved.
After the third step, the water has passed through all clarification and treatment processes.
Water that’s good enough to drink!
More questions about how the sewer system works? Contact the experts at JETT Pump & Valve today!