Why does steam rise from sewers

Then the answer might be that the steam is being pumped alongside the sewers. This is a way of creating and delivering energy throughout the city. In some areas, utility companies supply steam to a few blocks at a time.

Sudden bursts of steam may be leaks in the pipes delivering steam to these areas. Rainwater falling onto the hot steam pipes may turn into steam itself and rise up to the street level. This can happen even when temperatures above ground are very hot. As previously mentioned, it may contain dangerous substances. Some arid states in the US allow greywater use for irrigation, but even then, it has to be treated before reuse. The other reason city sewers get so hot is condensation. Condensation is the part of the water cycle where vapor converts back to liquid again.

To specify, what happens is that the surrounding warm air turns vapor into water when it meets a cool surface. Heated water vapor can also turn back into liquid when it encounters cool air. In the sewers, condensation occurs when cooler water like rain or melting snow flows into maintenance holes and comes into contact with the hot pipes.

I mentioned New York and its billowing plumes of steam earlier, but where does it come from — or rather, why do some sewers cough steam out? Detroit uses steam pipes too. Steam comes from certain city sewers because some places use steam to power their homes and businesses. Piping delivers steam through the city under the streets, which contributes to the heat.

It also comes from naturally occurring condensation. They help manage the steam by directing it with large orange and white stacks to keep it from blinding traffic and burning people. What do people put down there?

Please, tell the world! We don't have a straight dope over here, not even a crooked one. Yup, here in the U. All that a truly progressive civilization requires. As for what people put down there that causes steam to rise … why, they put steam, of course. Large steam plants tended to be more efficient than small ones, and some industries have waste heat, so, where the density is high enough to support it, you may find centralized steam plants selling heating steam to their neighbors, distributing it in underground insulated pipes.

This page from the website for Con Edison, the energy utility in New York City, explains how it works:. Steam power is as much a part of Manhattan as subways and Times Square.

The first steam generation plant began operating in — six months before the first electric service. Detroit Thermal operates a district energy network in the city, including almost 40 miles of underground steam pipes that provide service to many of Detroit's best known buildings, including Cobo Hall, the DMC and the Renaissance Center.

The steam provides cost-effective heating, hot water production, and absorption cooling services, and it supports additional manufacturing processes, according to Detroit Thermal. Steam is entirely contained underground in the extensive network; however, water vapor is sometimes visible at the street level for two reasons. It most commonly occurs as a result of other water sources, such as groundwater, coming in contact with the steam pipes.

This is similar to putting water on a hot pan at home. On rare occasions, plumes can be visible due to failed steam traps or leaks in the network. When maintenance and repairs are required, steam service to the line is temporarily shut off to ensure safety for workers and the public.