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. 

The Unique Challenges of Wildfires for Water Systems

Recent wildfires in California’s Sonoma and Napa Counties have caused loss of life and significant damage not only to over 5,700 homes and businesses, but also to critical water infrastructure in the region.

In Santa Rosa, residents have been instructed to use only bottled or boiled water for drinking and cooking. According to the city's water engineer, the system is currently experiencing unusually low water pressure, due either to high volumes being used by firefighters or damage to infrastructure. She explains that when water pressure drops below a certain level, backflow prevention devices – particularly in the higher elevations of the system – many not work properly.

Loss of pressure is only one of the many unique and harmful effects wildfire can have on water systems. This 2013 Water Research Foundation report on the effects of wildfire on drinking utilities lists many more, especially the dramatic physical and chemical effects on soils, source water streams and water quality that would necessitate changes to treatment operations and infrastructure. In fact, according to the US EPA, long-lasting post-fire impacts (especially flooding, erosion and sedimentation) can be more detrimental to water systems than the fire itself. 

The WRF report also suggests mitigation and preparedness strategies for utilities, including using fire behavior simulators to identify areas to target for fuel reduction activities, such as this goat grazing program in California. The idea behind such collaborative programs is that the less vegetation fuel available for fires to consume, the better. 

The increase in wildfire incidents such as these across the country make it all the more important for water systems of all sizes to be prepared for the unique challenges of wildfires. A good way to start your preparation is by checking out WaterOperator.org’s listing of free wildfire resources by typing in the word “wildfire” in the search box.

No time to lose? The US EPA has a page of "rip & run" resources including this Wildfire Incident Action Checklist.

Disaster Management and Black Sky Events

Coming this October, AWWA will host a webinar entitled Water Sector Black Sky Resilience. A Black Sky event is a long-duration, widespread power outage that could, in turn, cause a whole host of additional catastrophes. 

According to The Electric Infrastructure Security Council, A Black Sky event can have many causes: high magnitude earthquakes, severe space weather, electromagnetic pulses or interferences in the upper atmosphere (the kind that a nuclear detonation might cause), hurricanes, cyber-terrorism, coordinated power grid assaults and more.

Hurricane Harvey has offered a glimpse of the impact a Black Sky event would have on water and wastewater systems and the communities they serve. Black Sky events would cause much longer-term outages than the typical hazard event, and help might not come as quickly, or as easily. Back-up generators might be able to provide a certain amount of power, as long as they are in working order, but what if the treatment chemicals you depend on run out and can't be delivered to you?

Last year, the National Infrastructure Advisory Council issued a 212-page report analyzing water sector disaster scenarios and these types of cascading failures - power losses that lead to water losses and the consequences of those losses. The report concluded that this was an area that needed more analysis and planning. The report also recommends that smaller systems be provided with training as well as assistance in partnering with larger utilities that have more resources. 

Clearly, the effects of a long-term water outage on public health could be devasting, and this is why it is important to incorporate Black Sky response and recovery considerations into disaster management plans. The good news is that if you have a disaster management plan in place, you are already heading in the right direction. Using tools such as this 2016 E-Pro Handbook II (Water), you can expand your plan to include even the most severe emergencies. And this resource form the U.S. Energy Information Administration can keep you updated with live energy disruption reports across the nation. 

The USEPA also has a whole host of tools to help your utility prepare for a Black Sky event including a Power Resilience Guide for Water and Wastewater Utilities, a Drinking Water and Wastewater Utility Generator Preparedness guide, and a video entitled "Power to Keep Water Moving" (click below to view). Finally, be sure to check out the U.S. Army Corps of Engineers' EPFAT tool, a secure web-based tool to input and store emergency power assessment data. Using this tool can help USACE provide temporary power faster, getting you the right generator at the right time.