Waste water treatment refers to sewage treatment. Sewage is a combination of waste from our toilets, sinks, showers, and bathtubs. It doesn’t take much to figure out how disgusting and unhealthy it is. Without the plants to operate and treat it, we would probably still be using things like outhouses, chamber pots, and wash basins. Typically, sewage is treated in stages.
The First Stage
First the sewage runs through a screen, which filters out solids, such as kleenexes, rags, plastic tampon applicators to prevent the main pipes from being clogged. Then a chamber called a grit chamber allows sediments such as sand, small stones, etc. to settle at the bottom. The sediments usually come from storm drains.
Next is the removal and breakdown of the biohazard waste. These end up in the sedimentation tank. As soon as it’s full and its flow is reduced, the waste is then allowed to turn into sludge and settle at the bottom. The biohazardous waste is then turned into fertilizer, incinerated, or dumped into landfills.
This used to be the only stage of treatment. However, the demand for higher quality water has called for a secondary stage of treatment.
The Second Stage
This stage allows for the biohazardous waste to break down and make good use of its bacteria. In this case, the waste in the sedimentation tank is pumped forward to another facility with a trickling filter or activated sludge process. The former is a bed of stones three to six feet deep in which sewage passes. Though plastic and other synthetic mediums are now being used for it as well. The sewage then flows to a second sedimentation tank to remove the excess bacteria.
However, the sludge process is becoming more of the trend now. This is due to the fact that it speeds up the breakdown process by allowing more air to come into contact with the sewage. The tank that provides that is the aeration tank.
After that, chlorine is then fed into the now fairly clean water to kill 99% of the bad bacteria before it is given to the receiving waters.
Some Environmental Issues
Unfortunately, some people also flush hazardous chemicals, such as motor oil and antifreeze. These are difficult to remove and have been causing health issues to sewage workers, disrupt pH balances and kill wildlife. Fortunately, many of those chemicals can actually be recycled and safely disposed of at community recycling centers.
Water is perhaps our most precious resource. It is very important that we keep figuring out ways to safely use it and protect it. Especially with the human population as our of control as it is, it is becoming more imperative than ever to keep more sources of drinking water available.