The City of Coos Bay does municipal construction projects to maintain and improve the city and better serve residents.

In December 2016, the City broke ground for an expansion and upgrade to the existing Wastewater Treatment Plant No. 2, located in Empire at S Empire Boulevard and Fulton Avenue. This project will replace and upgrade the current treatment plant, provide better water quality and be able to meet future needs of the community.


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Construction impacts, including detours and expected delays

No traffic impacts are expected at this time. 

The limits of the WWTP2 project will include 490 Fulton Avenue, Fulton Avenue west of S. Empire Blvd, and Fulton Avenue between S. Empire Blvd and Marple Street.

Trucks and equipment will enter the plant site from S. Empire Blvd and from Marple Street. They will exit onto Fulton Avenue and Marple Street. The roads adjacent to the plant site will be open to traffic at all times, but there may be brief delays with flaggers while equipment enters or leaves the site. Pedestrian access will be closed or limited on the east side of S. Empire Blvd.

Fulton Avenue west of S. Empire Blvd will be heavily traveled by equipment and trucks. City staff will be requesting the closure of this section of Fulton during construction hours at the February 7, 2017 Council meeting at 7:00 pm.


Wastewater Treatment Plant No. 2 Expansion and Upgrade

WWTP2 Panorama

The City of Coos Bay is constructing an expansion and upgrade to the existing Wastewater Treatment Plant No. 2. Plant 2 treats sewage for western Coos Bay, including Empire, Barview, and Charleston. The existing plant is over 50 years old and will be upgraded with current technology, new Sequencing Batch Reactor treatment basins, and UV disinfection. The plant will provide better water quality and the ability to meet current and anticipated DEQ standards for the future needs of the community. The new facility will be built at 490 Fulton Avenue, just north of the Lighthouse Market. The plant is designed with capacity for population growth for a minimum of 20 years. It will be built so that modules may be added as needed for future expansion.

M.A. Mortenson Construction and their local construction partners, Billeter Marine and Kyle Electric, will build the upgrades. CH2M in partnership with the local engineering firm SHN Engineers & Geologists Inc. designed the new plant.

A 1% interest DEQ State Revolving Fund wastewater loan with a $500,000 grant is funding the project. The total cost of the construction improvements is budgeted at $24,531,820.

The project started in September 2016 and is expected to be finished in late summer 2018. Piping connecting the outfall to the new plant site was installed in the fall of 2016 during the road project to reduce traffic delays for residents. Excavation will begin January 10, 2017 for the main basins.


Project Schedule and Current Status


Photos showing progress of the construction

1/2/18: Overview of site

1/2/18: Stairs will provide access for Operators

Miles of electrical conduit are installed throughout the project site

12/26/17: Trusses in place for the Operations Building

12/20/17: Overview of Site

12/5/17: Installation of air diffusers along bottom of SBR Tanks

12/4/17: Operations Building

12/1/17: Headworks

11/30/17: Overview of Site

11/30/17: Plant Piping

11/30/17: Installation of Grit Removal System in Headworks

11/13/17: Overview of Site

10/31/17: Headworks & SBR Tanks

10/24/17: Overview of Site

10/6/17: Top view of SBR Tanks

10/3/17: Overview of Site

7/28/17: Overview of site

7/27/17: Watertight testing for the East Tank

7/12/17: Overview of site

6/30/17: A wall divides the East & West SBR Tanks

6/30/17: Filling Equalization Basin with clean water for Watertight Testing

6/29/17: Overview of site

6/27/17: Looking into the East tank

6/17/17: The headworks starting to take shape

6/15/17: The West tank is halfway complete

6/1/17: Setting the rebar for the concrete tanks

6/1/17: Overview of site

5/23/17: Overview of site

5/17/17: Headworks Wall

5/15/17: Headworks going vertical

5/5/17: Overview of the site

4/17/17: Slab foundation for the headworks.

4/7/17: Wall installation and concrete work.

3/30/17: Pouring concrete and installing rebar for the walls.

3/23/17: Installing more rebar for the walls.

3/17/17: Installing reinforcement rebar for the walls

3/14/17: Beginning to tie rebar

3/9/17: Over excavating and replacing with rock and fabric

3/1/17: Both SBR basins excavated. Both SBR basins have been excavated. The geotechnical report had indicated that there was prior fill covering an un-named creek that once crossed the site. Once the fill was removed, the contour of the old water way was visible. The backfill is stabilization rock with geotextile wrapped around it, then layers of crushed rock with geogrid between the layers. The large rock is on the left side of the photo and the crushed rock on the right.  A roll of geogrid is at the bottom of the photo. With all components in place, the basins will have a firm foundation to rest on.

East SBR Basin Rock 2-22-17

2/22/17: East SBR basin. The east SBR basin has been excavated. The backfill with rock has started to provide support under the concrete basin.

Baker Tank

2/15/17: Baker Tank. The excavations are kept dry by pumping the water to a “Baker Tank”. Baffles in the tank settle out solids so that the water discharged to the storm drains is clean.

SBR Excavation

2/6/17: SBR Excavation.  Excavation continues on the east SBR basin

2-8-17 Sequencing Batch Reactor basin

2/8/17: Sequencing Batch Reactor basin.  View to the west from Marple Street up above the construction. This is the big basin dug for the Sequencing Batch Reactor. The brown object is a tree trunk that was dug up during excavation. Most of the basin has been dug down to undisturbed soils, but there is some old fill on the site that still needs to be removed.



2-8-17 Sequencing Batch Reactor basin with filter

2/8/17: Sequencing Batch Reactor basin. View to the east from Empire Blvd. This shows how deep the basins are. The white is filter fabric to help hold the bank during construction. There has been a lot of rain this week and the site is pretty muddy, but the contractor has begun to put rock into the excavated basins to form the foundation support. The rock will reduce the mud and make it easier to work.

SBR Soils

1/31/17: SBR Basin Soils. The Engineer, Geologist, and Contractors examine the bottom soils of the east SBR basin.


Staff leading the WWTP2 project.

The City has invested considerable effort into securing a team of engineers and contractors with extensive experience in wastewater projects. There are quality control procedures and levels of inspections to check at every step of the way. As with all construction projects, there are a lot of moving parts and pieces to make the job site function properly. Our team is there to ensure that each part is done correctly and safely for the plant to be constructed properly. While their experience is in different fields of construction, together they have formed a great team. They are passionate about their work and the successful completion of this project.

Jan Kerbo

Jan Kerbo, PE, Resident Project Representative

Jan is the representative for the City for the WWTP2 project.

541-269-1181 ext. 2206

Bob_Sanguinetti Bob Sanguinetti, Project Manager for Mortenson Construction

Bob serves as Mortenson’s onsite representative in managing the construction of the project from all levels (safety, schedule, budget, and quality) and acts in the interest of the City of Coos Bay as their Construction Manager.


Current city projects

Wastewater Treatment Plant No. 2 Expansion and Upgrade

Empire Boulevard

Pump Station One Upgrade construction photos

7/10/17: Setting Rebar for the concrete slab

6/19/17: Overview of Site

6/2/17: Setting up site to form the concrete pad

12/27/16: New generator that will serve Pump Station 1

12/1/16: New Pump Station building

10/10/16: Foundation for Pump Station Building


Summer 2017 Projects

Sanitary Sewer Project at N 2nd Street between Commercial Avenue and Market Street

Sanitary and Storm Sewer Project at Golden Avenue between S 4th and 7th Street

Sanitary Sewer Replacement West of Plant 1 (680 Ivy Avenue)

Sanitary Sewer Replacement at N 4th Street/Highland Avenue

6th Avenue Storm Culvert Replacement

Birch and Front Street Storm Sewer Replacement

4th, 5th & 6th Ave Sewer Replacement

Pump Station 1 Upgrade at Birch and Front