City navigates emergency repair of fragile storm drain 

Problem: When city of Huntington Beach, California, officials investigated reports of sewage odors, they discovered a storm drain was infiltrating groundwater heavily laden with hydrogen sulfide gas, fostering colonies of Thiobacillus bacteria that consume the gas and excrete sulfuric acid. The resulting acid had attacked the concrete storm drain, turning much of it into crumbly calcium sulfate (gypsum).

Solution: The city’s repair objectives were twofold: making cost-effective, emergency repairs on 515 feet of very fragile storm drain under 16 feet of soil and 5 feet of groundwater, and preventing further destruction from microbiologically induced corrosion, or MIC. The city selected the CentriPipe system from AP/M Permaform, which uses a precisely controlled spincaster to spray thin layers of high-strength, fine-aggregate composite concrete that adheres tightly to most substrates, casting a new concrete pipe within the failing pipe that is completely structurally sound, with no seams or joints. To prevent further damage and groundwater infiltration, two additional mixtures from ConShield Technologies were used in the centrifugally cast concrete: ConShield, which prevents MIC by making concrete permanently antimicrobial, and Crystal-X, which makes concrete watertight by filling voids in the cured product.

Result: The newly rehabilitated storm drain is completely structurally sound, and it’s also permanently and intrinsically watertight, antimicrobial, and MIC-resistant. 800-662-6465; www.centripipe.com.

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Coating used to repair 214-foot storm culvert

Problem: In northwest Ohio, an 11-foot-7-inch-by-7-foot-5-inch structural plate storm culvert was in need of repair and rehabilitation. The corrugated pipe arch structure ran under Interstate 70, so replacement was not a viable option. The selected repair system or lining had to be applied in situ, and it needed to eliminate corrosion, maintain the culvert’s hydraulics, and preserve its structural integrity.

Solution: The Ohio Department of Transportation decided to repair the storm culvert using a spray-applied resin system. The scope required the rehabilitation of approximately 214 feet of pipe arch. HydraTech Engineered Products’ PolySpray SS-100 was included in the project specifications. It offers a high-build, nonbrittle coating without sacrificing physical properties. It withstands mechanical shock, and a snap cure allows for immediate return to service. This high-build, seamless coating is perfect for waterproofing and encapsulation applications where rapid return to service is required. Before spraying the pipe arch, the contractor first removed all debris and then prepared the surface with an abrasive blast.

Result: The rapid-setting, semistructural, monolithic coating provided structural support as well as resistance to incidental chemical exposure. This lining system will extend the life of the pipe arch without impeding highway traffic or hindering hydraulic performance. 513-827-9169; www.hydratechllc.com.

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Speedy repairs solve sinkhole damage in days 

Problem: A 50-foot-wide sinkhole developed in the South of Market neighborhood in San Francisco. Surrounding debris fell into the hole and damaged 100-year-old cast-iron pipe, which caused water loss to the area. The hole also needed to be filled in order to restore street-level traffic. 

Solution: The superintendent for maintenance and operations at San Francisco Water Power Sewer and his engineers decided to use 12-inch HYMAX couplings from Krausz USA to repair the pipes in sections, rather than replacing all the pipes. This product was chosen due to its strength, ability to provide a strong seal while allowing surrounding pipe to move with the earth, as well as ease and speed of installation.  

Result: San Francisco Water Power Sewer was able to complete the repairs in a matter of days by replacing only damaged pipes, instead of weeks if entire lengths of pipe had been replaced. 855-457-2879; www.krauszusa.com.

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Internal joint seal used to stop potable water leak

Problem: Due to a leaky pipe, a city was losing 12,000 gallons of treated, drinkable water every single day. A fix was needed, and fast.

Solution: Miller Pipeline was called in by the city to rectify the problem using its WEKO-SEAL internal joint seal. “Dewatering the pipe to make repairs was not an option. The demand was too high,” says Ryan Cooper, WEKO-SEAL specialist. Whatever the fix was, it had to be installed underwater and under pressure. Cooper spent time training divers on how to properly install the seal, and monitored the divers’ activity via CCTV on land. Over the hole in the pipe, divers layered 6-inch, 18-gauge stainless steel backing plates to provide strength underneath where the WEKO-SEAL would be applied. Then, they took two double-wide seals and staggered them over the hole, providing maximum protection against future leaks.

Result: The fix was made in a fraction of the time that shutting services down would have taken and with immediate results. “It was beautiful: you could watch the geyser go down in a matter of minutes,” Cooper says. 800-428-3742; www.wekoseal.com.

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Combo and easement machines used for root intrusion

Problem: The city of Statesville, North Carolina, needed equipment capable of removing heavy root growth to keep sewer lines flowing.

Solution: To tackle its root problem, General Supervisor Clyde Fox combined the advantages of the city’s Vacall - Gradall Industries AllJetVac combination sewer cleaner along with an easement machine and chain cutter. The easement machine with a rubber track undercarriage effectively extends the Vacall’s power to remote off-road locations that are not readily accessible by the truck. “With an easement machine, the jetting hose can reach beyond 600 feet, giving you another 600,” says Pat Barrett, salesman for Rodders and Jets Supply, which provided the city with the Vacall.

Result: “I had a big root cleanout problem, and I found out the Vacall delivered a higher level of performance to power the chain cutter down in the 24-inch mainline,” Fox says. “The Vacall delivers 87 gpm at 2,000 psi, so it does a good job chopping up heavy root networks and washing them away.” 330-339-2211; www.vacall.com.