In the years to come and even now, the EPA is and will be mandating the cleaning of large diameter sewers across the United States. These sewers have primarily been constructed along creeks, rivers and wetlands. Access to these sewer lines by means of conventional cleaning methods is becoming more difficult due to wetland restrictions and costs involved in building roads into these areas where permitted. In 1998, Montgomery Watson had approximately 15,000 linear feet of large diameter pipe in Fulton County, Georgia along the Chattahoochee River in the Chattahoochee River National Recreation Area. Montgomery Watson had long suspected that there were severe I&I problems in this stretch of pipe. They contacted AMTEC to perform a CCTV of the system, but were unable to do so due to the large amount of debris and sediments in the pipe. Montgomery Watson contacted local contractors to try and clean the system but after looking at the job, none of them were able to perform the cleaning task due to several environmental factors: 1. Extremely rough terrain; 2. No tree removal allowed; 3. Roads could not be put in (No gravel could be laid.) There was only access to a manhole every 2,000 to 3,000 linear feet. This ruled out conventional cleaning whereby you must have access to every manhole. So, NT&C was contacted by Montgomery Watson and asked to take on the project using our patent-pending Jigawon Cleaning method. This method of cleaning utilizes a flow restricting device that used the existing sewer flow to create turbulence within the pipe, causing the material to be put into suspension and moved downstream where it is removed and taken to the appointed debris disposal site. Using this method, we were able to clean the system with access to only several manholes throughout the system.

Cleaning Device Called a "Jigawon", this patent-pending device restricts the existing flow inside the sewer and creates turbulence within the pipe, causing the material to be put into suspension and moved downstream. Extraction Device Debris is removed from a selected downstream manhole. The fluid and solid waste is moved into watertight containers. The fluid waste is then removed from the container and deposited back into the downstream sewer line. The solid waste is captured and dumped at a site suitable for sewer grit and debris. It is advised that the retention containers employed be covered and airtight in order to keep the aroma of the debris to a minimum. Site Set-Up The length of sewer line to be cleaned before debris extraction is dictated by the amount of debris in the line. Obstruction of the flow activity will determine the amount of line debris and the necessity to shorten or lengthen the cleaning operation before extraction is necessary. At the upstream end, the Jigawon (attached to the winch cable) is positioned and secured above the manhole. The Jigawon is inserted into the line and allowed to "inflate," thus creating the turbulence and head pressure required to move the debris downstream. The winch is a powered device with any chosen length of steel cable installed. With 5,000 linear feet of 3/8" cable on the reel, the weight of the apparatus will be approximately 6,000 pounds. The Jigawon is fed downstream at a rate and pace determined by the amount of debris encountered. At the downstream end a weir is installed and the extraction device placed at the manhole. The containers should be stationed as close to the downstream manhole as possible however, it is not uncommon to locate the containers up to 100 yards away should site circumstances dictate.

The following summarizes the cleaning effort in the Johns Creek Basin (Fulton County) from MH JC21182.0 through MH JC19004.0. The cleaning was performed using the Jigawon process on 14,760 feet of sewer trunk line. NT&C arrived at River Pines Golf Course on September 10, 1999 to commence work on the trunk line from MH JC21182.0. The following day NT&C commenced jigging from MH82. Jigging continued for about 1,222 feet of trunk line when the Jigawon would go no farther. The Jigawon was retrieved and the entire 1,222 feet of trunk line was re-jigged with similar end result. As such, it became a matter of concern as to the reason(s) for the Jigawon stopping at the same location. A structural defect was assumed which triggered a dye test of the pipeline. The test was done in close proximity of a void in the ground above the trunk line. The dye test revealed no structural flaws in that part of the line. NT&C succeeded in getting the Jigawon passed the problematic area by plugging the immediate upstream manhole, which created sufficient head to move it past the aforementioned locale. On September 20, 1999, NT&C moved the set-up point from MH82 to MH77 and continued the jigging. NT&C moved the Jigawon past MH76 before moving the winch and setting up at that location. The set-up was done concurrently with extraction boxes being placed adjacent to MH35 for the initial extraction. NT&C extracted a total of 46.38 tons from MH35 with the debris (sand) transported to a landfill. The winch was moved to MH33 on October 19, 1999. After a few days of jigging, 15.72 tons of debris was removed from MH31 and disposed of appropriately. The extraction set-up was next moved to MH21 while the winch was being placed over MH31. On November 1, 1999, the winch was moved and set-up at MH23, which happened to be on the property of the Country Club of the South. The jigging process continued from the latter manhole. The next few days saw 16.29 tons of debris extracted from MH21 and transported to the contracted landfill. It should be noted that permission was obtained from the Homeowners Association of the Country Club of the South before work was performed on the property. On November 4, 1999, the winch was moved to MH22, which still happened to be on the Country Club's property. At about the same time the Jigawon set-up point was being changed MH15 was also being prepared for extraction. Extraction at MH15 commenced on about November 15, 1999. By November 22, 31.61 tons of debris had been removed from the manhole. On November 17, 1999 about 12:15 PM, a leak in the sewer trunk line was detected 50 feet upstream of MH15 and adjacent to a waterway that led to the Chattahoochee River. Mr. Woody Bidwell of Fulton County Big Creek Operations was contacted and a crew was immediately sent out to stop the leak. However, this was easier said than done for some heavy-duty equipment had to be mobilized to gain access to the actual leak, which was several feet underground. After working several hours into the night, the leak was finally repaired. About November 29, 1999, NT&C moved the winch back to MH33 for some re-jigging. This action was triggered by the large amount of silt/sand that was observed in the sewer line between MH33 and MH31 while reviewing the Sonar/Tiscit tapes provided by AMTEC. On November 30, 1999, preparation of the extraction point at MH04 commenced. By December 6, 1999 jigging had already commenced from MH12. The following day, the winch was moved back to MH15. After a few days off, jigging continued from MH15. A couple of days later, NT&C moved the winch to MH12 and continued jigging. Extraction commenced at MH04 on or about December 18, 1999. By this time, the winch had already been moved over MH08. Jigging and extraction continued through December 22, 1999. On December 23, 1999 with the job completed, NT&C packed up the equipment and prepared to return to Texas. Due to inclement weather, the extraction containers were not taken to the landfill until January 3, 2000. A total of 37.78 tons of sand transported to the landfill was extracted from MH04.

The Johns Creek Trunk Line Cleaning Project confronted sensitive environmental issues. Most of the lines cleaned were located in the Chattahoochee River National Recreation Area in Atlanta, GA. The sewer cleaning methodology used to complete this project met all the stringent requirements of the National Park Service, a division of the United States Department of the Interior and left the park in its original condition. This cleaning project could not have been completed using conventional cleaning methods. Altogether, a total of 147.78 tons of debris (sand) was removed from the 14,740 ft. of sewer trunk line cleaned. Upon completion of the cleaning, AMTEC was able to complete the CCTV of the lines cleaned. Using Sonar/Tiscit video, AMTEC confirmed that the lines were clean to less than 1% of material remaining within the pipe.