It may be surprising to you that each time you flush your toilet, the water in your bowl is sent on a miles long journey to a treatment facility and then it is cycled back into environment. In fact, at some point in the future, you will be pumping that same water back through your pipes, but not any time soon.
Treatment facilities are designed to gather all the raw sewage from a city’s drain pipe system, which can be quite extensive, and cycle this water through a series of high-tech filtration systems that remove debris, deposits of fecal matter, and bacteria. Most systems operate in several stages; at least four stages.
In pretreatment all the big stuff is removed. That might include garbage waste, leaves, other such things. The water flow is controlled so that rocks and glass will settle to the bottom. Grease is sometimes skimmed from the surface in this stage as well.
In the next phase, sometimes called the ‘primary phase,’ the water is skimmed for other particulates and a second rough of skimming is done that will remove final grease and oils. Finer particulates can settle so they can be filtered out. Some plants will create soaps from the fats that are skimmed in this process.
During sludge treatment, which is the next phase, larger amounts of sludge are siphoned off using a centrifuge. These sludge tanks have anaerobic bacteria in them and will digest the bad microbes in the sludge. What happens to the sludge that is left depends on the facility, but it is sometimes turned into fertilizer factories where it is used in fertilizers and filtered back into the soil that way. It is during this phase that nitrogen and phosphorus are removed. Chlorination is done to disinfect the water in this part of the treatment.
The primary job of the sewage system plants around the world is to remove as much of the toxins and garbage from the water so that it can be returned to the soil. The earth itself is an amazing filtration system. As the water makes its way back down through the levels of soil, sand, rock and plant roots it is filtered naturally. Eventually, this water finds the way back to the water table that is deep below the earth’s surface. This is the water that gets pumped back to the surface by private wells and city wells.
The water is filtered a dozen times or more, from the time it leaves your toilet or shower drain. It is very important that we try to not inadvertently add things to our water supply that may not be filtered out completely. It is not advisable to not flush medications down the toilet anymore. Water treatment facilities are unable to remove one-hundred percent of the things that find their way into the supply. Once introduced to the water table, these sorts of things can stay in the municipal water supplies that you are using daily. Think about the things you are running down your drains.