North Shore Gravity Sewer Rehabilitation Project for Triunfo Sanitation District

The District has identified the North Shore Gravity Sewer (NSGS) System rehabilitation project as a priority to reduce potential for spills and address maintenance challenges. The existing NSGS is located along the northern shore of Lake Sherwood. KEH & Associates, Inc. (KEH) prepared and submitted an initial study, which identified four options to upgrade the North Shore gravity system. Based on that initial study, District has selected rehabilitation of the North shore sewer using the vacuum system.
KEH staff performed site visits with District staff to identify the extent and feasibility of rehabilitation required to accommodate the vacuum valves at each property, modifications to the existing 4-inch gravity sewer, and installation of the new central tank.


The scope of work involves the preparation of design plans and technNorthical specifications for the construction of the vacuum system, including demolition, civil, mechanical, structural, electrical, and instrumentation improvements.


Preparation of design plans and specifications for upgrades to the gravity system at 13 Lots (Lot # 176 to Lot # 203), and conversion to grinder pumps at 3 Lots (Lot 3 204, 206, and 208), are as described below:

Design of gravity system upgrades will include:


  • Upgrades of approximately 500 linear feet of 4-inch sewer main to install 1-foot lifts
  • Demolition of existing sewer collection tanks and 2-inch laterals at 13 Lots
  • New 4-inch laterals from existing 4-inch house laterals to existing 4-inch sewer main at 13 Lots
  • New vacuum valves for each of the 13 Lots along existing 4-inch sewer main
  • New skid mounted central vacuum tank system with building enclosure
  • New 500-feet of parallel 4-inch sewer for vacuum system extension to central vacuum tank.


Design of conversion to grinder pumps will include:


  • Separation of existing 4-inch sewer main between Lots 203 and 204
  • New grinder pumps at Lots 204, 206, and 208
  • Electrical service to new pumps
  • New 8-inch PVC to connect to existing 8-inch PVC gravity sewer along Trentham Road