Sewage and wastewater is a leading cause of water pollution. Historically a problem solved by piping it away from cities, it nonetheless has caused other problems in terms of contamination of clean water sources and turned major river systems into giant sewers, unusable for wildlife and humans. Today, many cities have opted for municipal water treatment that cleans out sewage and other pollutants before water is discharged back to the environment.
Sewage treatment was originally devised in Britain in the 19th
Century, where it spread to the rest of Europe and then to North
America. Sewage treatment was developed as a reaction to the “Great
Stink” that resulted from a drought that lowered the water level of the
polluted River Thames in London. Sewage treatment first focused on
incinerating the sewage and, much later, dumping it out in the sea.
Modern sewage treatment facilities gradually remove
impurities from water, usually through large filters, sedimentation
tanks, and digestive tanks, leaving out clean water. The remaining
sludge is processed further. Some of the sludge is sold as fertilizer
to farmers, while others are incinerated or dumped at sea.
Other, newer water treatment systems include ecological filtration
systems that use plants, animals, and microorganisms to remove organic
waste from water. Though smaller than municipal systems, they are
usually more energy efficient and can satisfactorily serve the needs of
factories.
Treatment facilities reduce pollution and make the
world a cleaner place. Through sewage treatment, water sources can
remain clean and free from contamination.
Stephen Salony’s interests include water quality management. Get related updates from his Twitter and Facebook.
