After you press the flushing lever or button on the toilet, what happens to what was in the bowl?
When the toilet is flushed, the entire contents are sent into a drain pipe. That pipe is connected to a sewer line or a septic system outside of the home. This outside pipe will collect lots of other waste too, like shower water, stuff from the kitchen sink, and anything else that is connected to a drain.
This waste is referred to as sewage. It will travel to either the home’s septic system to be liquefied by beneficial bacteria or sent to a wastewater treatment facility. In a city, all the pipes from all the homes connect to central pipes that lead to the treatment facility. The largest pipes can be so large that a school bus could be driven inside of them.
Why Is Sewage Treated?
Sewage must be treated because it contains lots of germs. Many of the diseases that have been so destructive to humans throughout history are directly tied to waste exposure. Even today, in places where sewage treatment is not available, the transmission of many diseases is known to occur.
Typhoid, polio, hepatitis A, hepatitis E, cholera, and even certain parasites can all be transmitted with sewage contact.
Once the sewage arrives at the treatment plant, it goes through a multi-stage process to remove the most harmful components of the waste. Chemicals are added to the “sludge” and it may be stored in large tanks for several days at a time to ensure it is safe.
Continued processing helps to remove the waste products from the sewage as well. That creates a separation. The treatment facility will have the waste, which can be dried and then used as fertilizer, and they will have clean water.
In some instances, the treated water can be repackaged and sold because it is safe to drink. The water can also be sent to farms or factories to be used again.
What About the Big Stuff that Gets Flushed?
You never know what might get flushed down the toilet. You might flush tissues when you run out of toilet paper. Maybe baby wipes or personal wipes are flushed. The products say they are safe to flush, but are they really safe?
That depends on the product. Toilet paper breaks down easily, which is why it is safe to flush. Some wipes are thicker and don’t break down as quickly. That means they become a “waste” product within the sewage line. These items must be removed from the liquid sewage so it can be processed properly.
Many sewage lines have grills and filters in place that catch the largest items that may get flushed down the toilet. These screens are then periodically cleaned so they don’t cause a backup in the sewer pipe.
Some screens are dumped into machines that grind up the waste so it can be treated with the other sewage. Other grinders just reduce the waste into something that is manageable and can be taken to the local landfill.
How Does a Septic Tank Work?
If a home is connected to a septic system, then a toilet flushes the waste into an underground treatment structure on that home’s property. The tank will lead to a drain field or an absorption field after helpful bacteria have processed the waste so it is broken down properly.
Within the septic tank, the solids will settle to the bottom to begin forming a sludge. Oils, grease, and other materials remain at the top. The liquids leave the tank and go into the drainage or absorption area.
Eventually, the sludge within the tank builds up enough that it must be serviced as there is no longer any place for the liquid waste to go. A professional servicing agency then comes out, removes the sludge from the tank, and the system continues to operate as normal.
Most septic systems need to be serviced once every 3-5 years under normal use.
Why Is This Important to Know?
By knowing what happens to the water and waste in a toilet after it is flushed, it becomes easier to take care of our environment. Certain things, like kitty litter, coffee grounds, and prescription medicine, should never be flushed down the toilet – even if the product recommends this.
That is because the treatment process is not always 100% effective. Some items can survive and be recycled into the environment. By understanding what can be flushed, we can recycle much of what we currently flush away.