Steam vs. UV: There may be an alternative to the pipe-lining methods DC Water plans for Soapstone sewers | Forest Hills Connection |

by Marlene Berlin

At Wednesday’s public meeting on the Soapstone Valley sewer rehabilitation project, at least one member of the community will ask the National Park Service and DC Water whether the work needs to be so invasive.

As described on page 6 of Appendix E, Statement of Results:


Approximately 6,100 [linear feet] of sanitary sewer pipe infrastructure within Soapstone Valley sewer system would be rehabilitated using trenchless technology…. Cured-in-Place Pipe (CIPP) is a trenchless rehabilitation technology that involves inserting a resin-impregnated felt liner into the existing pipe or main pipe. This liner is then cured in place with water or steam…. With this technology, most of the construction work takes place on existing shafts. Given the site limitations in the study area, construction of access routes to certain wells would be required.

The statement of results went on to say that access to heavy equipment will require trails. They will be 16 feet wide, but in some places the trails will be wider than 20 feet to allow for maneuvering of equipment.

Marjorie Share, a member of the ANC 3F Parks & Trails Committee, is particularly concerned about the heavy equipment trails and the resulting loss of up to 371 trees. (See page 26 of the Environmental Impact Assessment, “Impacts of Alternative 2”)

It’s a little hard to see, but the trees to be removed are marked with pink x’s. The project would be limited to the area within the black lines. The purple lines are the existing paths. To view the original image and other maps of the project area, download Appendix B here.

She knew there had to be a better way. She started digging and came across Ultraviolet Cured-in-Place Piping (UV CIPP) or UV curing. This technology does not require heavy equipment like the steam and hot water curing method and therefore has a much smaller footprint in hard-to-reach areas like Soapstone Valley. It can also be a cheaper technology. It is more expensive to clean the heavy equipment that the steam and hot water process requires.

UV curing was the process used to reline a sewer line in Medicine Lake, Minnesota. The project was led by SEH, an employee-owned engineering, architecture, environmental and planning firm in Minnesota working on infrastructure projects.


Share contacted SEH’s Dave Hutton for more information. I was invited to an interview.

Hutton informed us that the UV curing technology has been used in the States for about 10 years and in Europe about 20 years after it was developed in Germany. It took the US much longer to adopt this technology as trenchless technology (meaning no pipes have to be dug up to replace them).

Hutton said the Medicine Lake project included sewers that run between the lake and people’s homes, “so getting the steam/hot water equipment back to the manholes would have been quite impossible,” Hutton said. “The UV curing method and equipment was a great solution to line the sewers in these very difficult conditions. It was the first UV curable liner used for a Minnesota city and I was very impressed with the technology and process and would definitely consider using it again given the right project and circumstances.”

JC Dillon of Peoria, Illinois was the contractor SEH used for the Medicine Lake project. Hutton told us there about 10 companies across the country doing this work.

The soapstone project public meeting will be held Wednesday, June 26 from 6-8 p.m. at the Forest Hills of DC Assembly Hall (4901 Connecticut Avenue). Marjorie Share and others will be curious to see if UV curing or other new technologies could be used in Soapstone Valley.

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