Sewer Cleaning Hawaiian Style

The Island of Oahu Provided the Backdrop for an Challenging Cleaning Project
By Joshua Nezat — Apr 12, 2013

JigawonDuring summer 2011, work commenced on a project to clean what Jigawon Inc. contracting considered the “Mother of all Siphons,” which crossed Kipapa Gulch in Hawaii, located on the Island of Oahu.

Jigawon entered into a working relationship as a subcontractor to Eckerd Brandes Inc. (EBD) to perform the project. EBD is a premier sewer rehabilitation company serving the Hawaiian Islands. It is owned and operated by the Higbee brothers, Jeff and Chuck Higbee.

There were many challenges to clean the Kipapa Gulch siphon. This siphon was unique in its design due to the geographical layout of the Gulch. The siphon was approximately 1,695 ft in length and consisted of three barrels — two were 18 in. in diameter and the third was 20 in. The sewer lines coming from the upstream structure were laid stair-stepped as the line descended down the sloping side of the gulch toward the bottom to reach a depth of 300 ft. Once the line reached the bottom of the gulch another siphon was needed to go under the creek bed. At this point, the sewer line made a 90-degree bend and continued up the sheer face of the gulch. Then, the sewer line went vertical for more than 300 ft then another 90-degree bend turned it back to a horizontal position and into the downstream structure.

The owner of the siphon had concerns of possible buildup of material within the lines. The siphons had not been successfully cleaned since the system had been installed many years ago. The owners had attempted to clean the lines using high-pressure jetting equipment, but felt that their attempts had not been satisfactory. This was due in part to the fact that they had been unsuccessful in moving a sewer tool completely through the line using conventional sewer cleaning equipment. The difficulty in part was due to the high velocity of the water and the 300-ft vertical aspect of the line.

The patented Jigawon sewer cleaning system uses the existing flow of a sewer to remove material and does not require bypass pumping. The system restricts the existing flow inside the line, increasing turbulence within the pipe consequently suspending the material causing it to move downstream. The system uses low-pressure water at high volumes in order to achieve material suspension during the process. Whereas high-pressure pumping systems use 2,000 psi at 80 gals per minute (gpm), the Jigawon uses 15 psi at 2,000 gpm. The debris is removed from a selected downstream manhole and the fluid and solid waste is moved into a watertight container. The fluid waste is then drained from the container and deposited back into the downstream sewer line, while the solid waste is captured and dumped at a site suitable for sewer grit and debris. There are two types of Jigawon: Jigawon I and Jigawon II, which operate in the same fashion.

Jigawon I is for pipe diameters from 8 to 60 in.,and the Jigawon II is for diameters of 60 in. and larger.

Prior to setting up the cleaning system, Jigawon crews observed that the structure appeared to be surcharged. This was a bad sign. But after a closer inspection, it was determined that the removable bar screens (which cover each out going lines) had become impacted with floatable materials such as rags and toilet paper. This caused the water level to rise several feet until the water flowed over the top of the screens. The bar screens had to be removed and cleaned prior to the installation of our roller apparatus. The owners were prompt to respond to our cry for help. The bar screens were cleaned the next day.

But to the crews’ disappointment, the bar screens had to be cleaned every day to lower the water level in the structure in order for work to proceed. Crewmembers had to take it upon themselves to perform this smelly, nasty and unpleasant task every morning. This may have been the worst part of the project.

The Jigawon winching system was installed on the west side upstream structure, but had to be removed nightly due to past issues with vandalism in the area. The authorities made it known to the Jigawon crews that vehicles and other equipment had been pushed over the edge of the property and into the gulch. The only access to the west side junction box required crews to drive through the historical Kipapa Gulch military storage facility. This section of the gulch is home to 128 concrete bunkers built into the walls of the gulch. Each bunker contains more than 4,000 sq ft of floor space. During World War II, these bunkers stored ammunition and it is rumored that nuclear devices may also have been secured there.

Each of the three sewer lines connecting the two structures were systematically cleaned using the Jigawon. The cleaning device had no problem making the shift from a sloping horizontal line to traveling up the 300-ft vertical incline straight up, pulling behind it more than 1,300 lf of cable. It was an encouraging moment when the crews’ Jig came into the downstream structure as it completed its trek, pushing all waste material ahead of itself. The process was repeated until all three lines were cleaned.

Using Jigawon’s patented extraction system, all material and debris were captured and transported to the landfill for proper disposal. The downstream structure where the extraction was taking place was situated in between homes and apartment complexes. But using state-of-the-art silenced pumps, the contractor received no complaints from the residents. And due to the air tight extraction system, the odor of the sewer was never an issue.

After about three weeks, the cleaning was completed. Each line was then to be inspected, but due to a constant full pipe of water, state-of-the-art sonar equipment was employed instead of televising equipment. This portion of the project was completed by EBD. As you can imagine, it was not possible for a tracked inspection tool to make the journey through so many bends and then make the vertical climb into the downstream structure. Each line was required to be strung with a small cable and the sonar tool was then pulled through each line until all three lines had been completely inspected. The sonar gives you an amazing visual of the interior of the pipe. It can detect any type of anomaly, such as debris, cracked pipe, missing pipe and so on. The inspection confirmed that the pipe was free of all debris. This is good because we do not get paid unless it’s clean.

It was a challenging project, but at the end of every day we made our way back to our condo in Ko Olina located near the beach. It was there the next day’s job plan was drawn up in the sand as we sat on the beach drinking Mai Tai’s or hanging out at the luau eating tasty roasted pig.

Joshua Nezat is media director for Nezat Training and Consulting, which is based in Splendora, Texas.

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