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WaterOperator.org Blog

Articles in support of small community water and wastewater operators.

Managing Sanitary Sewer Overflows (SSOs)

Managing Sanitary Sewer Overflows (SSOs)

The U.S. EPA estimates that approximately 23,000 to 75,000 sanitary sewer overflows (SSOs) occur in the United States each year. An SSO is defined by the release of untreated sewage into the environment through an overflow, spill, basement backup, or unpermitted discharge before completed treatment at the sewage plant. These overflows can degrade water quality, cause property damage, and pose serious threats to public and environmental health due to the release of harmful pollutants, disease causing microorganisms, metals, and nutrients into the environment. 

Section 301 of the Clean Water Act prohibits the discharge of pollutants to any Water of the United States from a point source without a National Pollutant Discharge Elimination System (NPDES) permit. To address compliance challenges associated with SSOs, the EPA recently completed a National Compliance Initiative that first began in 2000 to reduce the discharge of raw sewage in national water ways.

SSOs occur through debris or grease blockages, root intrusion, vandalism, inflow and infiltration, improper design, aging infrastructure, operational mistakes, and structural, mechanical, or electrical failures. Typically, the most frequent culprit takes the form of blockages. After an overflow, clean up and response is not only expensive, but traumatic for the impacted communities.

In Queens, NY a sewage backup on the Thanksgiving holiday weekend of 2019 flooded the basements of approximately 100 homeowners creating a putrid odor and exposing the community to harmful pathogens. Liability for residential damages and repairs to the pipe was projected to reach millions of dollars.  The culprit for the backup? While operators initially theorized a grease induced fatberg was to blame, investigation later revealed a collapsed sewer pipe instigated the SSO.

In New England and around the country, many communities maintain collection systems of 100 years old or more. Aging infrastructure exacerbates SSO prevention challenges. As years of wear on system equipment increases, the likelihood of mechanical or electrical failures as well as the opportunity for inflow and infiltration increases. Pipe deterioration due to natural freeze-thaw cycles, environmental conditions, water flow, and water chemistry can also increase the likelihood of structural failures. When this deterioration is not routinely inspected and maintained, resulting failures will only add further hydraulic stress to the system.

The frequency of SSOs can be reduced significantly through preventative maintenance and the implementation of an appropriate asset management program. To upgrade your preventative maintenance program, an article from the March 2017 Kansas Lifeline discusses the basics of lift station maintenance. The Georgia Association of Water Professionals provides a more comprehensive guide of collection system maintenance practices in its 2016 guide Wastewater Collection System Best Management Practices.

Developing an asset management program will allow systems to plan for the replacement or rehabilitation of aging pipes, pumps stations, valves, manholes, and collection system infrastructure. During program development systems can predict and plan for population changes, capacity objectives, equipment deterioration, and more. To encourage proper asset management of collection systems, the EPA developed the CMOM program. CMOM stands for Capacity, Management, Operations, and Maintenance.  The information-based management approach encourages dynamic collection system management through the prioritization of activities and investments. Utilities can access how well their current practices meet the CMOM framework using this Self Assessment Checklist and the EPA Evaluation Guide for CMOM at Sanitary Sewer Collection Systems. Follow up this evaluation by integrating CMOM best practices into a new or updated asset management program using this blog post.

Even with the implementation of these programs, systems should still prepare for the event of an unexpected overflow. As in Queens, NY, preventative maintenance and asset management did not stop the SSO on the Thanksgiving weekend. Systems must be prepared to respond swiftly with a Sanitary Sewer Overflow Response Plan. These emergency response plans will limit potential damages and reduce community distress. By combining preventative maintenance, asset management, and emergency response planning, systems can ensure that their community and its environment have the best protection from SSOs.

Spooky Sewers and Things That Go Bump at the Treatment Plant: 2018 Edition

Spooky Sewers and Things That Go Bump at the Treatment Plant: 2018 Edition
An October chill is in the air and darkness is falling earlier and earlier. It must be time to share our annual bone-chilling list of some of the wierdest, wackiest and downright most frightening water operator stories we came across this year (check out last year's list here)!
 

First, can you imagine what it would be like to get sucked through a sewer for over a mile? Well, it happened to this man when his safety harness came undone back in 2010. And although he survives, the crappy experience is surely something he will never forget. 

While we are talking collections O&M, here's a video describing one characteristic of a successful wastewater operator: a strong stomach. Another characteristic? Knowing not to "fling this on your partner."  And believe me, you don't want to know what "this" is!

Sometimes, though, what flows into a sewer simply doesn't come out, no matter how much you work on it. That is when you call in the professionals: sewer divers.

This is exactly what the water system in Charleston, SC did when they could not clear an obstruction earlier this month. They sent specialized sewer divers 80-90 feet deep into raw sewage in complete darkness to search for the obstruction with their hands..

What did they find? You guessed it: a large mass of "flushable" wipes. Lucky for us, the water system documented the whole episode on social media, but respectfully shot the pictures in low-res for our benefit.

If you want to dive deeper into the topic of sewer exploration, we double dare you to watch this video about a man who swims through Mexico City's wastewater system on a regular basis to keep it working. 

Other types of obstructions have to be dealt with in other ways. This past summer, utility workers spotted an alligator swimming in the Mineral Springs, PA wastewater treatment plant. A private contractor hired by the state Fish and Boat Commission had to use dead animals as bait to try and snag the gator with a fishing hook. 

You have to admit, wastewater often gets a bad wrap. To prove this, just ask any operator from Baltimore's wastewater treatment plant what happened there back in 2009. That was the year they had to call in experts to deal with a 4-acre spider web that had coated the plant. According to a scientific paper that appeared in American Entomologist, the “silk lay piled on the floor in rope-like clumps as thick as a fire hose” where plant employees had swept aside the webbing to access equipment. Scientists estimate the megaweb contained about 107 million spiders

Finally, it wouldn't be Halloween without ghosts, or ghost water, to be more precise. What is ghost water you ask? Well, pervasive leaks and long repair delays are causing water to disappear in Kansas City, Missouri (a kind of haunting experienced by water systems all across the country it seems). According to this 2017 article, nobody knows exactly where the water is going, but the water department points to faulty meters, theft, aging pipes and abandoned houses. Spooky!


Featured Video: The Science Behind Exploding Manhole Covers

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