Featured Video: The Science Behind Exploding Manhole Covers

Every season has its challenges for public works departments, and now that spring is just around the corner, it is pretty obvious that this past winter came with more than its fair share. Yet we are not in the clear quite yet, as this news story about two manhole explosions just a few weeks ago demonstrates. In fact, as winter winds down, accumulated road salt compounds corrode through underground electrical cables, causing sparks to ignite gases that can build up in confined spaces. With over 2,000 annual incidents in New York City alone, exploding manholes are not a joke: they can be dangerous, destructive and downright difficult to predict.

And while large cities like New York City are especially prone to these incidents due to aging infrastructure and the sheer amount of underground electrical cables present, small towns are definitely not immune. For example, in 2014 the tiny town of Sauget, Illinois (pop. 150) experienced an explosion so powerful manhold covers damaged overhead power lines.  

 Find out more about how road salt compounds contribute to this problem in this week's featured video.  

While explosions are the most dramatic hazard associated with manholes, research suggests that manholes are in general one of the most dangerous work locations for water system staff. In fact, according to AFSCME, fully one-third of all injuries/deaths of workers occur in or around manholes. Check out this safety presentation hosted by Michigan WEA for more information on the types of hazards presented by manholes and how to protect yourself from them. 

And if you have any lingering doubts about the force, and destructive power, of an expoding manhole, take a look at this video. 

It's Alive! Spooky Sewer Creatures and Things That Go Bump at the Treatment Plant

Every water system has its stories — whether a particularly forceful water main break or sewage overflow, an unwelcome water tower visitor, or a “worse day ever” inside the treatment plant.

This Halloween season, we thought we would share some of the spookiest water operator videos and news stories we have come across, all with one thing in common: they really happened! (Because we all know that truth is scarier than fiction.)

Let’s start with a quick video and resource about a rare, but certainly not unprecedented, hazard. Hopefully, you will never encounter this slow-moving fleshy blob in your wastewater treatment plant or collection system, but just in case you do, you can thank this blog for warning you!  

No, it isn't an alien from another planet. This nightmare blockage is nothing but a nest of tubifex worms. Along with red worms, blood worms and midge flies, these worms are a normal and occasional nuisance to waterwaster operators, as they can clog filters and eat good bacteria. Although it isn't easy to get rid of them, this website offers hope. 

Speaking of blobs, earlier this year a water utility worker fell off a water main and found himself stuck in a blobby, muddy trench. The more he moved, the more stuck he got. Luckily for him, his nightmare didn't last long — fellow workers quickly came to the rescue, using their knowledge of trenching and excavation safety principles.

One thing is for sure: strange encounters are never far away when you work in the water business. In fact, sometimes spooky creatures are as close as the microscope slides in your lab.

Wastewater plants in particular house microbiological zoos of the strangest kind. But don't worry about what you can't see, because these creepy-crawly microorganisms are really the good guys at treatment plants. The predatory suctoria, for example, uses its spines to suck out the nutrient-rich cytoplasm of organisms it has speared, aiding in breaking down and removing nutrients and organic matter. Or the mysterious Tardigrade (aka water bear) seen below in this video whose appearance usually indicates good BOD degradation. Water bears can survive in outer space, extreme radioactive environments and high temperatures, making them one of the "toughest animals on earth".

In addition to strange creatures, strange happenings can also be part of the day-to-day life of a water operator. This Wessler Engineering blog post entitled "Is Your Wastewater Treatment Plant Haunted? describes an acoustic phenomenon known as "water hammer" that can occur inside the walls of a home as pipe fluids suddenly stop or change direction. This same thing can occur at the treatment plant when automated solenoid valves abruptly open or close, causing a sudden loud boom or knocking. It would be enough to make any night-shift operator jump! 

Finally, we leave you with a story that is sure to give you the shivers. Recent hurricane flooding in Houston has jarred many manhole covers out of place (more than 65, in fact), and somehow a man fell into a pit that feeds underground sewer lines carrying residential wastewater. After over a week underground, the man was finally discovered by utility workers who were nearby making repairs and heard a disembodied voice crying, "I am here, I am here!". After tossing the man snacks from their lunches, rescuers were able to haul the man to the surface. Thankfully this story has a happy ending, but be sure to watch where you are walking this Halloween.