Avoid Cross Bore Disasters

Directional drilling is a fast and efficient way to install underground pipe and conduit, but when a gas line is bored through a sewer line, disaster can ensue.

Cross Bores – when a line bores through a sewer line – have been the cause of catastrophic events in the past. To combat this issue, municipalities, utilities, contractors, and the trenchless industry must join forces to ensure proper pre- and post-inspections are conducted and avoid disaster.

There are almost always more connections than what surface observation suggests. The reality is that subsurface most likely there are more connections than marked after an 811 call. Municipal utilities must learn to spatially map out subsurface infrastructure during routine maintenance to improve accuracy for 811 locator requests.

Auditory systems with GPS capabilities (SL-Rat) and CCTV Camera systems have made an incredible positive impact on finding the missing conditions. By using an auditory inspection system like the SL-Rat (OMAG has several to loan to municipalities) a municipality can map their sewer system.  Then they can use a CCTV camera (OMAG has grants available for these) through sewer mains.  In this way, line taps can be identified and recorded to inform utilities or system owners, and potential hazards can be addressed prior to drilling. Equally important is to make post-drill inspections to confirm lines have not been breached during installation of a utility.

While gas or communication lines are typically what we think of when we hear the term cross bore, directional drilling of other utilities can negatively impact the integrity of our sewer systems as well.

Developing a partnership between utility owners and municipalities is critical if cross boring events are to be identified and addressed to keep communities safe. Developing a comprehensive prevention program between the municipality and utility owners where they share the costs and get cross bore inspection work done economically and responsibly is a win-win for the municipality, utility, and the customers.

NASSCO, whose mission it is to set standards for the assessment, maintenance, and rehabilitation of underground infrastructure, identified the need to set standards for proper cross bore prevention and detection. The worst thing that can happen is if an operator finds a cross bore and does nothing about it. Standard assessment and cleaning of mainlines could also potentially uncover cross bores masked by roots. If a cross bore is hiding behind roots that have infiltrated a pipe and the roots are cut, disaster could occur. A significant benefit of a regular chemical root control maintenance program is the ability to kill the roots without cutting or damaging pipes (OMAG has a root control grant with Duke’s Roots).

In addition to municipalities and utilities working closely together, the relationship between utilities and contractors is extremely important for the implementation of a successful cross bore program. Developing a relationship with contractors laying pipe or conduits and working with them to identify hazards or challenges and working to develop unique solutions, provides better quality data and a higher level of confidence that we are keeping our communities, homes and businesses protected.

The most common question pertaining to cross bore inspection and remediation is always “Who is responsible?”  The answer: “When is comes to keeping our community safe, we all are.”

For more information about the SL-Rat, CCTV camera, or Duke’s Roots grants contact William Sheppard, OMAG Risk Management Specialist at wsheppard@omag.org.


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Using OMAG's SL-RAT - Feedback From 2 Cities That Have Used It

Last Fall, OMAG purchased 3 Sewer Line Rapid Assessment Tools (SL-RATs). The reason for the purchase of this equipment was to loan them to our member municipalities to update and develop sanitary sewer maintenance programs. Following are some questions OMAG’s Risk Management Department asked these cities, with their responses. We thought the rest of our member municipalities might like to see what was said about participating in the SL-RAT program. Here are the responses from Jay Neal, City of Durant and Matt Duke, City of Muldrow.

Question: Why did you choose to participate in the OMAG SL-RAT programs

  • Durant: We have an aging wastewater distribution system. We are seeing an increase in the amount of sewer related issues. Having been in my position only 2 years, at that point, I felt it was incumbent upon us to do a “fitness” report on our sewer system. The SL-RAT tool provided the means to do that.

  • Muldrow: We knew we had problems in our collection system and wanted to isolate the problems. We also have inaccurate and outdated prints that do not show all of our manholes, or the manholes were not in the correct location on the prints.

Question: Did the SL-RAT meet your expectations as to its usefulness? If so, how?

  • Durant: It exceeded our expectations. As with all newer technologies, it’s easy to be reluctant to accept its usefulness. However, the SL-RAT proved up to the challenge. Once we figured out its limitations and the best time of day to put it to use, it gave us an accurate picture of our sewer infrastructure and provided the data necessary to analyze it.

  • Muldrow: Yes, we have a great idea on where our problems are and we now have a good working print (map).

Question: What will you do with the information you acquired from using the SL-RAT?

  • Durant: When possible, we are keying in on the lines that were substandard to determine which, if any, need replaced or repaired. If we are able to use it again after we have serviced those lines, we will be able to start trending problem areas and creating work-arounds.

  • Muldrow: We will now be able to jet our problem areas and use the camera we obtained through an OMAG grant to find out why the lines are having problems. We will also be able to make prints of our collections system and have accurate locations of our manholes.

Question: What are some of the positive aspects of using the SL-RAT for improving your sanitary sewer inspection and maintenance program?

  • Durant: The biggest advantage the SL-RAT provides is to afford our department a proactive way to deal with sewer problems instead of putting us in a more reactive posture.

  • Muldrow: We have isolated problem areas that were unknown and eliminated other areas we suspected had blockages. We found that just physically opening all or our manholes was also a great benefit, because we were able to find some that were in need of rehabilitation and sources of I & I.

Question: What, if any were some of the complications you encountered while using the SL-RAT?

  • Durant: There are some variables that you have to contend with when using the SL-RAT. However, these issues are systemic to the environment and less to do with the equipment itself. Satellite hindrances, such as cloud and tree cover, inclement weather, and undulations in the sewer lines that lead to improper or inaccurate ratings did occur. There were a few instances where the two components would not synchronize. Some of those were user error and the others were undetermined in origin.

  • Muldrow: None, it was a very efficient system.

Question: Would you recommend that other Oklahoma municipalities  take advantage of OMAG’s SL-RAT program? What advice would you give them to take full advantage of their time using the SL-RAT?

  • Durant: I would highly recommend that other municipalities take advantage of what the SL-RAT can provide, in regard to their wastewater distribution system. The integration into Google Earth and the ability to export to Microsoft Excel for in depth analysis is worth the price of admission in and of itself. Furthermore, it provides an excellent form of accountability for the department and a quantifiable way of determining problem areas and justifying repairs. As far as advice to other municipalities, I would say, “know the general pulse of your town; meaning, know your off-peak times of the towns sewer usage. The tool will provide a more accurate read during low usage times on your respective lines. Have a dedicated team assigned to this project with little or no distractions to take them away from the project. Have a plan that provides the most coverage possible for the time you will be using the SL-RAT. Lastly, work with your upper management to ascertain their goals for the usage of this product.”

  • Muldrow: Absolutely. This tool gives you a chance to quickly assess what areas of your collection system are needing maintenance and makes you locate manholes that could have been lost over time. I found that having a three-man team made the process move along as quickly as possible. By having two guys working the machines and one in front of them locating manholes and popping lids, we were able to move through town at a quick pace. This tool gave us the same information we had previously paid for, at a fraction of the price.

For more information about the SL-RAT or to schedule having one brought to your municipality to assess your sewer system, contact William Sheppard at (800) 234-9461 ext. 138 or wsheppard@omag.org.


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6 Things to Consider Before You Jet a Pipe

High-pressure water cleaning systems have become the tool of choice for maintaining sanitary sewer systems, because of their effectiveness in dealing with grease and sludge, along with their ability to partner with pipe inspection cameras. However, before you fire up your jetter and go off to battle underground monsters, there are six things to keep in mind.

1.    What the heck is down there?

  •  Jetters do a great job on soft stoppages like grease, sand sludge, and even ice. However, when it comes to roots, they are not the preferred tool for the job. If you’re not sure what is happening in the line, you can try to send an inspection camera down to take a look, but if the line is blocked you won’t be able to see much. Remember, cameras can’t see underwater any better than you can. So how can you tell what the blockage is?

  •  First, if the line in question has anything to do with food service, there is a better than even chance that grease is the problem. Using your powers of deduction, you can conclude that blockages in lines leading from restaurants, multi-family dwellings, and any kind of institution involving food service (schools, nursing homes) are likely to be made by grease and maybe rags. The same is true if the pipe in question originates in a factory or industrial facility that flushes lubricants, solvents, or any type of organic material down the drain. Also depending on where you are, sand can be a persistent problem.

 2.    Shake, Rattle, and Roll

  •  Does your jetter unit have a way to vibrate the hose while it is in the pipe? The vibration function is used to break up the surface friction between the hose and the pipe, so you don’t get the hose stuck. One of the first things contractors noticed when they invented jetting some 40 years ago, was that when you connect a hydraulic hose and rear facing nozzle to a pressure washer and shove it down a pipe, there is a chance of getting the hose stuck. And anytime that happens it’s the beginning of a long day, because you’re going to need to get the excavator out. That is why every legitimate manufacturer of high-pressure jetters today has a feature that allows you to vibrate the hose while in use.

 3.    Yes, size matters

  •  Are you using the correct size of hose for the pipe, you are trying to clear? Another excellent way to get your hose stuck in a pipe is by using the wrong size hose, which is surprisingly easy to do. When working with high-pressure water, the philosophy is to use the largest hose that will fit into the pipe. This is because hoses with a larger inside diameter don’t have as much pressure loss due to water friction. All things being equal, the larger the hose, the more pressure at the nozzle. The more pressure at the nozzle the easier it is to do the job.

 4.    Check your water

  •  Since high-pressure water is doing the work down the line, it makes sense that you have enough of it. If you happen to be using a large device with a holding tank, such as a trailer jetter, your only challenge is to make sure the tank doesn’t run dry. Most of these units have an automatic shut-off that keeps this you from making this mistake. However, if you are using a jetter that draws water from a garden hose, a little more attention is required. Most municipal and well water systems in North America deliver approximately 5-6 gallons a minute in flow, but it is recommended that you make no assumptions. Get a 2-gallon bucket and measure how much time it takes to fill it. If you’re close, don’t take the chance, because you could accidentally starve the pump of water and cause cavitation. Cavitation is the second most popular way to kill your pump, so pay attention to details.

 5.    It don’t mean a thing if you don’t have that swing

  •  Keep your hose moving. The preferred technique for jetting a line is to work the hose back and forth: push the hose 2 feet forward, then pull it back a foot, then push forward 2 feet and back a foot. The maximum cleaning action comes when you pull back the hose, not pushing it. As you pull back, the angle of water flow exiting the nozzle scours the sides of the pipe, magnifying your cleaning efforts. If you keep the hose moving, you’ll do a better job and do it in less time.

  •  There is another reason to keep it moving. Because of the fluid dynamics of high-pressure water flow, turbulence can cause vortices to form just behind the nozzle when you are doing the job. These vortices, if stationary for any length of time, can suck sand, loose dirt, grease, or sludge in behind the nozzle, causing it to plug up and trap the hose down in the pipe. Getting your hose stuck in the pipe, no matter what the cause, is a bad thing. Digging it up is usually the only viable option. Again, very time consuming.

 6.    Don’t freeze up

  •  Statistically, freezing is the number one way to kill your pump. If you live in a place with four seasons, you’ll find it surprisingly difficult to keep your pump from freezing when you are doing work on a frigid day. The damage can take place before, during, or after the job, and can affect your hose as well as your pump. If your unit has an antifreeze tank, please get in the habit of using it whenever temperatures are close to freezing. If your unit does not have this feature, introduce antifreeze to keep it from freezing when you are driving to and from the job. Just disconnect the hose that runs from the output valve to the hose reel swivel. Then pour antifreeze into the inlet as you start the motor on the unit, which will draw the fluid through the pump. When you notice antifreeze exiting the output valve, turn off the motor. Then, using an air compressor to blow the water out of the hose (remove the nozzle). Make sure this has been done before you drive to the job, and again before going back to the shop. During the job, limit the amount of time the units sits without water flowing through the pump. Turn the unit on frequently, running water through the bypass system to keep it warm. If you make it someone’s job to pay attention to the pump, then you’ll improve the odds of it surviving till spring.

  •  You probably noticed that most of the points can be summarized by “paying attention to what you are doing” and “do your homework”. Jetters are fantastic tools for our industry, able to address most modern sewer line problems better than other tools at our disposal. But, like everything else in life, greater power comes hand in hand with greater responsibility. If you sweat the details, a jetter is an incredibly versatile and profitable tool that can transform your sewer maintenance program.

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Sewage Lagoon Basics

sewage lagoon is a large pond into which the sewage or effluent from the sewage system flows. Sewage lagoons are also called effluent ponds.

The sewage and effluent are broken down by germs in the lagoon. The sun and wind play an important role in the working of the lagoon. They provide light, warmth and oxygen to the water. This is necessary for the growth of the bacteria in the water.

The light, warmth and oxygen also aid the growth of algae in the water. Algae give the lagoon its greenish color. Algae helps the bacteria break down the sewage and effluent.

The wind helps with the evaporation of the water and serves to get oxygen into the water. It also creates waves which help stop insects from breeding and living in the water. Disease-causing mosquitoes, for example, need still water to breed.

For a lagoon to be able to break down the sewage or effluent properly and to be a healthy place it must meet the following requirements:

  • It must not be more than 1 meter deep

  • The banks need to be sloped at approximately 15 to 20 degrees and made of concrete, gravel or rock. This stops the wave action from eroding (breaking down) the banks

  • There must be no grass, trees or other vegetation on the banks or surrounding area which would stop the sun and wind action needed by the lagoon

  • The water must be free of vegetation or objects which stop the lagoon's surface wave action or create still patches

  • It must be surrounded by a high fence with a lockable gate to keep children and animals out

Lagoon overflows

Where there is only one lagoon in the sewage disposal system, it will have an overflow situated directly opposite where the pipe carrying the sewage or effluent enters the lagoon. If there is more than one lagoon in the system, the overflow will be in the last lagoon.

The overflow releases water from the lagoon system which has not been removed by evaporation. New lagoon systems are required to be designed so disposal occurs by evaporation only. They should not rely on overflow, except during very heavy rainfall periods. However, where an existing lagoon system uses an overflow method, the overflow should not create a flooded or swampy area suitable for mosquito breeding, or where it may contaminate drinking water or the environment.

Lagoon maintenance

Lagoons which are not working properly or are poorly maintained or damaged may be dangerous to health.  Signs of a lagoon which is not working properly are heavy overflow, mosquito breeding or a bad smell.

Signs of a lagoon which is poorly maintained or damaged include broken fences and gates, trees, shrubs or grass on the banks, grass growing and other objects in the water causing still patches.

Unsafe sewage lagoon
To be properly maintained the lagoon should be checked frequently and any problems reported to the authority responsible for providing maintenance. It is important to report any of the following:

  • eroded or broken lagoon banks

  • lagoon banks which are not angled at 15-20 degrees

  • trees and/or other vegetation growing in the lagoon, on its banks or in the area around the lagoon

  • bad smells given off by the lagoon

  • water which is not a light, flecked green color

  • still areas on the surface of the lagoon

  • signs of mosquitoes breeding in the water

  • damaged fences or gates that cannot be locked properly to keep out animals and children

  • rubbish in the water

  • a swampy situation near the lagoon (possibly caused by the overflow) which could provide mosquito breeding areas

  • grass on the banks of lagoons, particularly growing at the edge of water, which can provide ideal mosquito breeding areas

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Responding to a Sanitary Sewer Overflow Call - What Do I Do?

Responding to a Sanitary Sewer Overflow Call - What Do I Do?

Scenario: You are the “on-call” person for after-hours responses to sewage calls. It’s Sunday afternoon during a four-day holiday weekend when many people have overnight guests and of course they’ve enjoyed a large traditional meal.  You are dispatched to a call across town where a slow draining and gurgling toilet complaint has been called in to your municipality. You respond immediately and drive directly to the address. When you arrive, the resident tells you that for the past few days the toilet has been making gurgling sounds when it was flushed, except for the last time, when there was no gurgle and the water didn’t go down.

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Sewer Solutions - Know Your Nozzles

Sewer Solutions - Know Your Nozzles

For pipeline cleaning professionals, fast and efficient water jetting is essential to maximizing profitability and the return on investment for the jetter. Yet many contractors fail to optimize jetting performance because they don’t understand the basics of two critical components: nozzles and tips.

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Does Your Municipality Have a Fog Problem? - What IS FOG?

Does Your Municipality Have a Fog Problem? - What IS FOG?

FOG is a widely-used acronym for “fats, oil and grease”, the substance that most commercial kitchens produce as a byproduct of cooking and food preparation. Fats, oil and grease typically make their way into the wastewater when dishes are being washed or kitchen equipment is being cleaned.

Grease that accumulates in pipes and plumbing fixtures, in sewer lines and in sewage treatment plants creates numerous, expensive problems. As a result, most wastewater systems in North America and in many countries around the world require fats, oil and grease to be removed from wastewater before that effluent enters the sewer system.

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Sanitary Sewer Backflow Prevention

Sanitary Sewer Backflow Prevention

Every year, OMAG receives 1,000 (+/-) tort claims that are filed against municipalities that participate in the Municipal Liability Protection Plan (MLPP). Sanitary Sewer Overflows (SSOs) are one of the most frequently filed claims we receive. In the past 10 years OMAG has paid over 6 million dollars in damages due to SSOs. In a recent interview with Todd Lansdown, Wastewater Maintenance Supervisor with the City of Bartlesville since 1981, Todd recommended these “BEST PRACTICES” to assist in SSO prevention and dealing with customers who have had one of these  unfortunate events. He noted that these policies and procedures are not all his own ideas—they’ve been passed down and refined over the years.

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Sewer Maintenance - Clean-Outs and Back-Water Valves

Sewer Maintenance - Clean-Outs and Back-Water Valves

Clean-outs and back-water valves are the resident’s key to keeping the private sewer service in good working condition and protecting the home from sewer back-up problems.

A clean-out is a vertical pipe that provides access to a property’s sewer service, allowing homeowners or plumbers to clear blockages that disrupt service. A clean-out cap is typically white PVC or metal, about 4 inches in diameter, and located near buildings.

Both homeowners and tenants should locate and inspect their clean-out cap before a plumbing emergency occurs. Keeping the caps screwed onto the clean-out helps prevent possible sewer backups caused by yard debris, dirt, and other items entering the sewer system. Capping also stops excessive inflow and infiltration, which can overload the system and cause overflows. 

A back-water valve is the resident’s protection against sewer back-up into the structure. If water tries to back up from the sewer mainline, the valve prevents sewage from backing up into the building. Back-water valves are typically located either outside near the building or in a floor drain in a basement. Those outside have a cap similar to a clean-out cap and a vertical pipe down to the valve. Size and maintenance needed depend upon the manufacturer of the back-water valve. 

You can protect yourself from sewer problems by making sure you have an accessible clean-out, keeping your sewer line in good condition, and by making sure you have a functional back-water valve.       

The photo below shows a back-water valve with 2 clean-outs. The caps have been removed to show how the back-water valve allows fluid to flow in only one direction. 

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