Featured Video: What is Water Hammer?

Any water or wastewater operator should possess a strong understanding of water hammer and the implications it can have on piping systems. Water hammer, also referred to as hydraulic shock, occurs when there is a sudden change in flow velocity or direction that results in a momentary increase in pressure. If high enough, the pressure can cause damage to pipes, fittings, and valves. An example where water hammer can occur is when an operator rapidly closes a valve halting flow and sending a shockwave through the system. In Jefferson City, MO, operators responding to a ruptured water main created a second break during repairs as a result of water hammer. Pressure surges can also occur through unexpected power outages or equipment failures.

Engineers consider several variables when designing piping systems to limit potential for water hammer. Whenever a major change is made to the distribution or collection system, implications for water hammer should be evaluated.

This week’s featured video demonstrates how water hammer occurs and what it looks like using 100 feet of clear PVC pipe with an analog and digital pressure gauge. The host explains how engineers can modify the potential for water hammer in piping systems by manipulating the variables that make up the mathematic equation for the pressure profile of a water hammer pulse. Such design parameters include pipe size, recommended operating procures for closing valves, and more. Watch the video to understand how the design considerations for your piping system impact water hammer.

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.