Infiltration Reduction Pilot
The goal of this pilot project is to test a new method of sealing the sewer pipes and to reduce or eliminate the amount of groundwater that enters the sewer lines through cracks, separated connections, etc., a process called “infiltration.”
This project involves 88 Broadview homes in the area from NW 130th to NW 132nd Streets, from 8th to 12th Avenues NW (see map). The area has approximately 15000 linear feet of sewer lines; 5000 feet of main sewer lines under the streets and 10000 feet of side sewers - pipes that connect each home to the main sewer line.
Dec. 22 - Early actions underway for Broadview Sewer and Stormwater Improvements
Bravo, a contractor for Seattle Public Utilities, will be working in the Broadview neighborhood during January and February 2012 sealing sewer maintenance holes (MHs) to reduce both leakage out of and stormwater seeping into the MHs.
Bravo will be working on 4th Avenue and in the area from 12th Avenue to 8th Avenue between 130th and 125th Streets. They will be using the Sanipor flood grouting technology to seal the MHs. At least 70 MHs will be sealed through this process. Prior to initiating the work Bravo will inspect the MHs and note if any structural repairs will be required, such as bringing them to grade, replacing covers, or installing standard MHs. This work will be completed for the MHs that need it prior to grouting.
We do not anticipate that any of this work will cause an interruption of sewer service. Please contact Jim Johnson, Lead Project Engineer, at 684-5829 if you have any questions regarding this work. More information on the Broadview Sewer and Stormwater Improvements Project will be announced in first quarter of 2012 and will be posted here as it becomes available.
How it was done
SPU hired a consultant, Bravo Environmental, to perform a camera inspection of the sewer pipes from the inside, both main sewer lines and residential side sewers. They installed cleanouts in those side sewer lines that didn’t already have them. If side sewer lines needed to be repaired, SPU is doing that at no cost to the homeowner. Once those repairs are completed, the new grouting method will be tested to seal cracks in the lines.
The grouting was implemented with a two-part, non-toxic chemical process and was completed in sections, from one manhole to another. At each manhole, the lines were temporarily blocked (for no more than one day) and then the chemicals applied. Afterwards, the system will be monitored to see how effective the resealing has been. If successful, the process may be repeated elsewhere in the Broadview area.