Siphon Cleaning

While sewers are a conduit that convey water, no two cleaning projects are ever the same. Challenges may be due to the shapes and sizes of a sewer or because of the levels of debris. The debris may be light and will convey very easily or the debris could be extremely hard and compact and will require much effort to displace.

Adding to the challenge is the possibility that the lengths of reach may be very long and the access may be difficult. The sum of these challenges often makes the task seem nearly impossible.

Topping the list for difficult cleaning tasks would be siphon cleaning. Typically, these structures are taken out of service and cleaned. Bypass of a siphon is often costly and not always a viable option because they are often located under busy roadways or river crossings. If a structure was located under an interstate and bypass was not an option, the siphon would need to be cleaned live.

Recently, a state of Michigan owned-siphon that is maintained and operated by the Office of the Oakland County (Mich.) Water Resource Commissioner needed attention. Jim Nash is the Oakland County Water Resources Commissioner and is responsible for planning, developing and maintaining designated surface water drainage systems in Oakland County, located in southeastern Michigan. Based on previous inspection work, the county was able to conclude that maintenance was required. This siphon was built in the 1970s as part of a new crosstown interstate, a roadway that is a crucial route for east and west traveling suburban traffic.

As is the case with many structures such as these, the years of debris buildup had reached a significant level that would require attention. This particular siphon was a massive five barrel 5-ft x 10-ft box. Each barrel was 200 ft long. Some of the barrels were completely blocked and the entire siphon was in need of cleaning.

Without a viable option to bypass flow around the siphon, a creative solution was needed to clean this. Using Doetsch Environmental Services’ proprietary equipment — including but not limited to custom built machinery known as the Grand Volumetric Recycler and the Hyjector, which is specifically built for live cleaning coupled with the ability to recycle sewer water for cleaning — was vital for this operation to be successful. The specialized equipment extracts water and debris, separates the debris in a hopper and pumps the water through the Grand Volumetric Recycler, where it is systematically coarse filtered and then pumped on demand through the Hyjector for final filtration. This final filtration allows the water to be conditioned for reuse. Finally, the water is pressurized and conveyed through the high-pressure hose to the cleaning nozzle to suspend the debris in the siphon. Not only is the high-pressure water used for debris suspension, but it is also used to provide propulsion to the cleaning nozzle. The cycle of extracting water and debris, filtering and pressurizing through the cleaning nozzle continually repeats during the duration of the cleaning activity.

Debris Obstacles

In addition to the normal debris (sand, grit and gravel), there was also a large amount of trash that had flowed in from upstream creeks and drainage ditches. This ranged from bottles, balls, shoes and anything else that would float. This trash was mixed with a sanitary grease mat that had to be removed before cleaning could begin. There were also several logs that had washed in through the various large diameter inlet pipes at the influent chamber. These logs still had their limbs attached and would eventually need to be cut out of the pipe using chain saws. The trash and green waste was so plentiful that additional filtering devices had to be coupled together in order to filter these objects and not discharge them back into the system.

The debris was loosened, suspended and retracted to the access point using high-pressure water. At each access point, all material was vacuumed, unless it was too big to fit in the vacuum tube (as was the case with the logs). Large debris may be removed by a clamshell or a winch. The debris hoppers were hauled to the landfill when full. Construction tools were also found in one of the barrels (evidently they were forgotten before the siphon was put into service).

Another unique obstacle of the project was the need for traffic flow to be maintained at this busy intersection. With not much of an easement, the equipment would stage a single turn lane while not impeding the second turn lane so that traffic impact was minimized. This aided the motorists’ travel at the intersection and also provided safety for the cleaning crew.

After cleaning, the barrels were inspected using sonar and/or CCTV to provide a condition assessment as well as cleaning verification. It is important for the system owner to have this data to ensure that cleaning was performed in accordance with NASSCO standards and document tangible proof that all debris was removed from the siphon.
The Hyjector and Grand Volumeteric Recycler enable Doetsch Environmental Services to clean in varying conditions and in all types of pipe. The specialized equipment ensures that water is continually reclaimed and debris is continually extracted to prevent downstream migration. Effective debris removal in each segment(s) is very important for a successful cleaning project. This process has been used to clean sewers up to 4,600 ft in length and has capability up to 6,000 ft. This equipment is also extremely adaptable in difficult access situations.

Doetsch Environmental Services is a fifth-generation 116-year-old family business with two generations actively engaged in the day to day business. The exciting aspect of family business is a generational exchange of ideas throughout the years. Doetsch Environmental Services has been constantly challenged to reinvent itself in both services provided and changing customer base. Many of the services that were once performed are no longer needed and Doetsch Environmental Services is in the relentless pursuit of cutting edge technology and techniques that we bring to the marketplace. We do not forget the simple principles of sewer cleaning upon which this company was founded or the business values set forth by the preceding generations of family, while simultaneously integrating best in class service and techniques, including custom building machinery and equipment to most efficiently and effectively serve our valued customers. It is clear to see the steadfast link with the equipment processes and techniques that remain constant. As more challenges are presented, Doetsch Environmental Services will continue to innovate and overcome these obstacles.

Historical company photos show methods of cleaning that we consider archaic by today’s standards, perhaps it was a worker on a small leather scooter propelling himself up the pipe with a bucket to remove the debris or trying to clean a mainline with snap together wooden rods. As time progresses, we are much more technologically advanced with high pressure water and vacuum systems. As Doetsch Environmental Services continues to provide environmental solutions for projects such as this Oakland County siphon, we continue to conquer challenges while never losing track of our roots.

Joe Schotthoefer is operations manager at Doetsch Environmental Services, based in Warren, Mich.