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Municipalities can cost-effectively reduce sanitary sewer overflows with upgraded equipment and cleaning practices.

Aggressive Maintenance Can Tame Sanitary Sewer Overflows

Dec. 6, 2022
CASE STUDY: Cash-strapped municipalities can cost effectively reduce SSO's to virtually zero with proper equipment and proactive cleaning technologies.

Case Study by KEG Technologies

Most municipalities are fully aware that preventing sewer overflows is a national enforcement priority for the U.S. Environmental Protection Agency (EPA). Yet many still struggle to stay compliant.

Too often, when municipalities are short-staffed and must maintain miles of sewer line, they end up simply responding to emergencies. But a growing number of proactive municipalities are now choosing to utilize more effective tools and techniques to help them to properly maintain their lines and to stay EPA-compliant.

According to the federal website:

EPA’s compliance goal is to eliminate sanitary sewer overflows (SSOs) from municipal collection systems and to ensure that wastewater is being conveyed to treatment plants in accordance with the requirements of the Clean Water Act. To eliminate SSOs, EPA uses a mix of compliance and enforcement tools.

SSOs are overflows, or releases from sanitary sewer systems, and are illegal under the Clean Water Act. SSOs have a variety of causes, including but not limited to severe weather, improper system operation and maintenance, as well as vandalism. EPA estimates that there are at least 40,000 SSOs across the U.S. each year. The untreated sewage from these overflows can contaminate the nation’s waters, causing serious water quality problems. It can also back up into basements, causing property damage and threatening public health.

“Today, one of the greatest underlying causes of SSOs is sewer pipe blockages due to growing tree roots that enter through line defects or openings, combined with inappropriate materials sent to sewers," says Dan Story, operations manager at KEG Technologies. "This includes fats, oils, and grease along with products like baby or facial wipes, sanitary pads, and tampons. Non-degradable wipes are a particular problem when flushed because they get hung up in roots and start catching all the grease and debris. Everything builds until the line is stopped, which leads to an SSO."

Based in Spartanburg SC, KEG Technologies is a manufacturer of sewer and storm line products including nozzles, chain cutters, and camera-nozzle systems. Of note, the company is a member the National Association of Sewer Service Companies (NASSCO).

Proactively preventing blockages and removing those in progress is critical because failing to do so can lead to devastating consequences. “Sewer pipes fill up from any blockage and can back up into homes or run down the street, so the federal government mandates that a certain amount of sewer line must be properly maintained annually, or fines are levied,” adds Story. 

Fortunately for municipalities, using the industry’s most effective tools and techniques can virtually eliminate SSOs, and in some instances, have already done so for decades. This is first achieved by preventing most sewer line blockages with powerful nozzles and efficient cleaning.

Next, camera nozzles can quickly identify developing blockages during routine cleaning without deploying a separate camera crew. When the blockages must be removed, utilizing various cutters including robust chain cutters can do so quickly and efficiently. Finally, learning the most effective cleaning techniques from experts in the industry can further facilitate proper sewer line maintenance.

Preventing SSOs

Properly designed, operated, and maintained sanitary sewer systems are meant to collect and transport all the sewage that flows into them to a publicly owned treatment works (POTW). However, occasional unintentional discharges of raw sewage from municipal sanitary sewers occur in almost every system.

The first line of defense against such SSOs is to use effective tools, specifically powerful nozzles, to sufficiently clean sewer lines and remove any debris so it does not accumulate to become a blockage. In this effort, using high-performance Tier 3 nozzles instead of lower performing Tier 1 or 2 nozzles can be an important advantage.

Although rated for water efficiency (Tier 1: about 30% efficient; Tier 2: 50-60% efficient; and Tier 3: 75-98% efficient), top Tier 3 nozzles can also more reliably direct the most force with less water, at lower pressure, to remove debris. The most efficient Tier 3 nozzles, such as KEG’s Torpedo and OMG models, are designed with fluid mechanics engineering on a par with the aerodynamics of race cars.

After exiting the jetter hose, water travels into the body of the nozzle before moving through smooth, curved channels. This design enables the water to maintain its power and speed before entering the nozzle’s replaceable titanium ceramic inserts, which help to straighten the water stream. The water is further funneled to enable an even tighter water pattern to emerge.

The power and reliability of a superior Tier 3 nozzle can help operators clean more line, more effectively, before the sewer truck crew needs to stop work and drive to a hydrant to refill the water tank before resuming work. According to Story, a Tier-1, 30-degree drilled nozzle running 72 gallons a minute at 2,200 PSI will only exert 13 pounds of force to move debris nine feet away from the nozzle. In contrast, a high-efficiency Tier-3 nozzle running 60 gallons a minute at 2,000 PSI will exert 98 pounds of force nine feet away.

Identifying Obstructions

The EPA can hold municipalities accountable for preventing SSOs in hundreds or thousands of miles of sewer line annually. In addition, proper cleaning and maintenance must be accomplished.

KleenSight camera-nozzle system provides the ability to clean sewer and storm lines and view roots in a pipe while recording upright high-definition video.

“Chain cutter nozzles that utilize water pressure are more efficient and can deliver the required torque to cut through thick masses,” advises Story. “The high-pressure water enters the chain cutter nozzle chamber and is directed to spin the cutting chains at high velocity."

As an example, he points to a powerful chain cutter that has a high-speed, high-torque, water-driven design. The chain cutter can eliminate heavy root blockages, as well as scale, rust, mineral deposits, hardened grease, and accumulated debris.

“When you remove the roots and debris from the lines, it becomes easy for future debris to pass through on its own," add Story. "This eliminates the problem of backing up and sanitary sewer overflow."

Proactive, Not Reactive

When SSOs occur and municipalities are out of EPA compliance, it can be difficult to do more than react. However, proactively maintaining sewer line with the most effective tools and tactics is vital to prevent SSOs and quickly resolve them if they occur. For this reason, KEG offers customized training programs to municipalities that specifically target the challenge of SSOs.

With the goal of eliminating SSOs, the training program corrects common cleaning errors, such as excessive operator speed going up the sewer line, which ends up wasting water, labor, and time when multiple passes are required. Proper line assessment and cleaning speed are taught, which allow operators to adjust to circumstances as needed while minimizing water use.

When operators complete the training, most will understand how to “chop up the debris and let the flow of water work like a conveyor belt, carrying the debris out.” They will be trained to “go from manhole to manhole and clean in a single pass.” It takes a fraction of the time and resources to make one pass versus making several passes to remove the same material.

The results of being proactive with equipment and training to minimize SSOs have been more successful than might be expected.

“One city in Arizona that we have worked with has not had an SSO in 30 years," noted Story. "So, it’s all about staying on top of your game."

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