What Happens When You Flush

What Happens When You Flush

Introduction SWOOSH! You hear this sound every time you flush a toilet. But did you ever stop to wonder where everything that you flush down winds up? Getting rid of waste is often a complex process. That process can stretch over (or under) many miles in your city or town.

Where Does Waste Come From? Where Does It Go? Human waste is called sewage. In most homes, it is created by using the toilet, sink, or anything that makes water dirty. If all this sewage reached our drinking water, it would make it unsafe. For more than two billion people around the globe, waste either piles up on the land or runs into lakes and rivers. Millions of people die each year, sick from drinking water that sewage has made unsafe. Sewage treatment experts are working hard to solve this problem, but it is a huge task.

Lucky for us, the sewer pipes in our homes don't just empty into our drinking water. Instead, in many cities and towns, all of this dirty water ends up in the local sewer.

Inside the Treatment Plant Small sewer pipes join up to form bigger and bigger pipes. The sewage moves through this large group of pipes to a sewage treatment plant. Here, the water is cleaned. Things in the water that can make people sick are removed.

Not all sewage treatment systems are alike. One common type cleans sewage in the following way: STEP 1 A big screen (think of a giant kitchen strainer) removes large items such as rocks, sticks, and garbage. That way, they don't jam up the treatment plant's machines. STEP 2 What is left over after this process is called sludge, which is thick, dirty water. The treatment plant helps bacteria grow in the sludge. These bacteria eat the sludge to break it down.