Booster Chlorination System
Project Status
Click here to see status updates
Project Details/Neighborhood
Various locations around Mercer Island
Background
The City obtains its water supply from Seattle Public Utilities (SPU). Chlorine is added at SPU’s treatment facilities before it is distributed to Mercer Island and other cities through SPU’s transmission and distribution system. In 2014, due to E. coli-positive sample test results, the City issued multiple Boil Water Advisory notices. Subsequently, a Coliform Response Action Plan was developed, and approved by the Washington State Department of Health (DOH). The Action Plan identified solutions to reduce the contamination risks in the City’s water system. One major item identified in the Action Plan is the construction of a new booster chlorination system. A well-designed booster chlorination system will ensure the chlorine level is maintained at, or boosted to, an acceptable range from the receiving point from SPU’s supply line to the end of distribution lines throughout the entire Island.
Description
The Booster Chlorination System project will create the ability to:
- Increase chlorine levels in the water supply from SPU.
- Increase chlorine levels at the main pump station and reservoir to ensure residual chlorine remains at the appropriate levels throughout the City’s water system.
- Circulate the water in the reservoirs to provide uniform mixing with chlorine.
Project Timeline (Target Completion Date)
Q4 2022
Estimated Budget
2021 $995,000
2022 $2,510,000
Contact
www.mercerisland.gov/water21-28
Rona Lin, P.E., City of Mercer Island Utilities Engineer: (206) 275-7806 or rona.lin@mercerisland.gov
Status Updates
January 2024
In November and December, consultants and contractors completed the remaining Startup Testing at the Reservoir site and successfully performed the Startup Testing at the SPU68 PRV Station on SE 40th Street. On December 21, 2023, Harbor Pacific Contractors officially reached substantial completion. Currently, there are only a few remaining punch list items which are anticipated to be fully completed by end of March 2024.
Week of October 30th Update
Photo 1: Reservoir East Yard Paving – during paving
Photo 2 and 3: First Booster Chlorination Training Session 10.19.2023
In late August, several issues were identified during the first I/O testing of the Booster Chlorination System at the reservoir site. The I/O testing verified nearly 200 different system functions between the control programs and various system components. Results of the I/O tests identified several work items for the consultants and contractors to modify and improve. The majority of the physical work items were electrical modifications which the contractors have been working on in September and October. The programming consultant conducted troubleshooting and installed updates to the control system programming during these two months. Final I/O testing should wrap up by the end of 2023. Contractors also completed several punch list items at the Reservoir site this month, including pavement restoration in the East Yard.
The first training session for the water crew was held in mid-October regarding the metering pumps and hypochlorite generators. The training session was conducted by the equipment vendor, TMG Services. The next training session is scheduled for mid-November and several more may occur in the coming months.
Update 8/29/2023
Partial street closures on August 30th between 8am and 5pm. will affect the neighborhoods of 89th Ave SE, 44th St, 4400 block of East Mercer Way and 9700 Block of SE 40th. The City contractors are performing roadway pavement restoration. Vehicle access will be restricted on your street during paving. Please plan early to park your vehicle away from work zones to avoid delays getting in and out of your property. The streets will be re-opened to regular traffic at the end of the workday.
8.30.23 Postcard
8.30.23 Door Hanger
Update 7/12/2023
Photo 1: Newly painted 24-inch inlet pipe inside reservoir pump station
Photo 2: Rockery wall construction restarted in late June 2023
Photo 3: PLC panel and cabinet installed at SE 40th PRV site on July 10, 2023
Photo 4: Sodium Hypochlorite Generation System room near completion – taken on June 29, 2023
Rockery wall reconstruction in the East Yard took place in late May and is anticipated to be completed in July.
In early June, HPC completed tank mixer installation in the south reservoir. They also worked on preliminary punchlist items.
Control system programming is in progress to integrate automatic control of the Booster Chlorination System into the new Water SCADA System. A tremendous amount of coordination and collaboration among the City team, design team, control programming consultant, and contractors will continue until the entire Booster Chlorination System is commissioned in early September.
The long-awaited PLC panel for SE 40th St PRV station was delivered and installed on July 10th.
Three milestone tests are required to put the Booster Chlorination System into operation. They are 1) Installation Test, 2) I/O Test, and 3) Functional Test (also known as the Startup). The Installation Test was conducted on June 29th. A second I/O Test will be scheduled for late July or early August. Currently, the Startup is scheduled for the end of August.
Update May 5th, 2023
This week, contractor crews assembled the reservoir tank mixers. They are still waiting for some parts, so the installation of the mixers will not be completed until next week. The process of control system integration continues, with a workshop set for next week with the City’s design engineers (Brown & Caldwell) and City’s water team to identify elements that need to be included in the software programming to integrate control of the Booster Chlorination System into City’s new Water SCADA System.
April 14, 2023 Update
Photo: new valve actuators
This week, contractors completed the installation of thrust blocks, valve stems, and valve actuators on underground piping outside of the reservoir building. Electricians will be on site next Monday 4/17 to install wires and connect power from the pump station out to the newly installed actuators. This project is expected to complete in Q3 2023.
Update 3/1/2023
Previously rescheduled construction activities will be occurring this week in the 4300 block of 89th Avenue SE. City contractors will be excavating the road to install new fittings on existing 24- and 30-inch diameter water mains. These mains will be shut down for the work, but no homes will be without water. Due to the size of the excavation needed for these water main connections, 89th Avenue between SE 43rd and SE 44th Street will be closed to through traffic from 7:30 AM to 5:00 PM on March 1, 2nd and 3rd (Wednesday—Friday).
Update 2/22/23
The scheduled road closure for this week (2/22-2/24) has been postponed due to poor weather conditions. The work will be rescheduled. For residents who received a door hanger notification of the closure, a new hanger will be placed when the work is rescheduled.
Update 2/21/23
Road work will be occurring this week in the 4300 block of 89th Avenue SE. City contractors will be excavating the road to install new fittings onto existing 24- and 30-inch diameter water mains. These mains will be shut down for the work, but no homes will be without water. Due to the size of the excavation needed for these water main connections, 89th Avenue between SE 43rd and SE 44th Street will be closed to through traffic from 7:30 AM to 5:00 PM on February 22, 23, and 24 (Wednesday—Friday).
Update 2/2/2023
During the week of January 17, Harbor Pacific Contractors (HPC) restarted construction work at the Reservoir site. This is considered a critical phase of the project because it involves major piping work near the “heart” of the City’s water system where the water supply is stored and distributed throughout the entire Island.
During this phase of construction, pipe modifications will be done by removing pipes and structures and installing new pipes, fittings, and equipment at the reservoir site and on 89th Ave SE, east of Reservoir.
Water main shutdowns are required for most of this work. Notifications will be provided to affected residents when water services and fire hydrants are temporarily shut off for the planned shutdowns.
HPC is planning to complete the piping work before the start of the high water-demand season, generally around May.
With the last of the long lead-time equipment anticipated to be delivered to the job site in July/August, the project completion is estimated to be in Q4 2023.
Update 10/25/2022
Photo 1: SE 40th PRV site – Concrete Pad for Davit System
Photo 2: Hypochlorite Tank Room with on-site Hypochlorite Generation System installed
Photo 3: Chemical tubing & electrical conduits feeds to north reservoir tank
SE 40th Street site
In September, Harbor Pacific Contractors (HPC) completed concrete equipment pads at the SE 40th PRV site. One is for the SCADA PLC panel and two are for the Davit system bases for the two new PRV vaults. The Davit system is a fall protection system for people working inside a confined space.
Reservoir site
During September, the hypochlorite generator system was delivered and installed at the reservoir site. Currently, most of the hypochlorite related system components have been installed and the contractor has completed most of the chemical tubing and conduit installations within the building and out to both north and south reservoirs.
In addition, approximately 60% of the electrical work has been completed. Most of the new conduits from the hypochlorite tank room to the reservoir pump room (where the main SCADA control panel is located) have been installed and are waiting for wire to be pulled.
HPC is on a temporary hold on the underground piping work at the reservoir site and on 89th Ave SE until the high water-demand season is over and their temporary bypass pumping system’s components/layout is approved by the City.
This project is anticipated to be completed in Q1 2023.
Update 7/28/22
Photo 1: SE 40th PRV site – new PRV station and new Flow Meter Station
Photo 2: Completed containment coating – sodium hypochlorite tank room
Photo 3: Electrical conduits and cabinets installed in reservoir pump station room (adjacent to sodium hypochlorite tank room)
Photo 4: Different angle for Electrical conduits and cabinets installed in reservoir pump station room
SE 40th Street site
Most of the work is complete. A new Pressure Reducing Valve (PRV) station and flow meter station replaces the old PRV stations.
Reservoir site
A few major work items have been the focus of construction including containment coatings, electrical conduit and chemical tubing installation, water heater installation, and west yard pipe restraints. On July 27th, factory acceptance testing for the sodium hypochlorite generation system was completed at the supplier’s shop. The system will be delivered to the reservoir site in August.
A significant amount of piping work remains at the reservoir site and on 89th Ave SE east of the reservoir. This work is temporarily on hold during the current high water demand season. This work will resume by mid-October.
This project will be completed at the end of 2022 or early 2023.
May 2022 Update
Photo 1: Finished Equipment Pad – Sodium Hypochlorite Tank Room
Photo 2: Finished Containment Floor – Sodium Hypochlorite Tank Room
Photo 3: PRV (Pressure Reducing Valve) Station Demolition – 9700 Block SE 40th Street
HPC completed placement of concrete for the equipment pad and the containment floor in the Sodium Hypochlorite Tank room in April. They completed the first of three water main abandonment locations during the first week of May. This work is to abandon an aging, 12-in water main between reservoir and 4400 block of E Mercer Way. It is anticipated this work will be completed by the end of May.
HPC has also started the PRV (Pressure Reducing Valve) station demolition at the 9700 block of SE 40th Street. The demolition of two existing vaults will continue into the second week of May.
May 5th, 2022 Update
A water main shutdown is scheduled for today, 5/5/2022 (Thursday), at 9700 Block of SE 40th Street. Our contractor will start preparing to demolish two (2) concrete vaults and replace the PRV (pressure reducing valve) stations in the coming days.
The shutdown will take place between 8AM and 4PM . No water services or fire hydrants are expected to be affected by this work.
May 4th, 2022 Update
A water main shutdown is scheduled for today between 9 am and 4 pm near SE 43rd St and 89th Ave SE Intersection. There will be no impact to the water services or fire hydrants of nearby residents. The shutdown is needed for the contractor to disconnect an old water main. This is the first of several piping modifications planned as part of this project.
April 2022 Update
Photo 1: Finished containment wall and new rebar for the equipment pads in the sodium hypochlorite tank room.
Photo 2: Wet tap on 16-inch main for the new hydrant installation (no water main shutdown needed).
Photo 3: New fire hydrant installed on 4400 block of 92nd Ave SE.
Photo 4: New fire hydrant installed on 4400 block of E Mercer Way.
In March, HPC completed concrete placement for the containment walls in the Sodium Hypochlorite Tank room. The concrete truck drivers’ strike within our region was ongoing until April 11th (Note 1). There will be two more concrete placements in the tank room - for the equipment pads and the containment floor.
HPC has completed two fire hydrant replacements - the 4400 block of E Mercer Way and the 4400 block of 92nd Ave SE. The crew also completed several preliminary and miscellaneous tasks for larger work items that are to take place later.
A combination of factors has hindered HPC’s progress since the beginning of the construction. These include 1) Long lead time/delays on materials such as ductile iron pipes, valves, fittings, flow meters, and other water parts, 2) Concrete truck drivers’ strike, and 3) SPU’s two pending water main shutdowns to re-configure their water supply line to Mercer Island. Prior to the completion of SPU’s work, HPC was not allowed to conduct work items that would impact SPU’s work.
Note 1: The strike began in King County in November 2021 and broadened in scope in December. Though the drivers returned to work on April 11, the union continues working on negotiations.
February 2022 Update
Photo 1: Installing # 4 rebar with epoxy in drill holes in hypochlorite tank room
Photo 2: Forms and rebar set in hypochlorite tank room
Harbor Pacific Contractors (HPC) started construction in the sodium hypochlorite tank room at the reservoir site in mid-January. This work will continue into March.
Concrete truck drivers in the region are currently on strike and may delay HPC’s planned schedule for pouring concrete slabs and equipment pads.
Staff continues working with consultant team on material submittals review and RFI (request for information) responses. Due to long lead times on a few critical items, schedule modification from HPC remains a work in progress.
November 2021 Update
City Council awarded a construction contract to Harbor Pacific Contractors (HPC) on July 20, 2021, and executed the Public Works contract in August.
Currently, the City and its consultants are reviewing material submittals from HPC. It is anticipated that some critical items may have longer lead times due to Covid related delays on manufacturing and delivery. The project starting date is undetermined at this time.
Construction is anticipated to start in February of 2022.
Update 7/7/2021
Bids were opened on 7/6/21 at 1 pm. see link below for more information
https://www.mercerisland.gov/publicworks/page/21-28-bid-booster-chlorination-system-project
Project Location (449 KB) Bid Award (1 MB) Door Hanger 5.24.22 (195 KB) Door Hanger 2.22.23 (249 KB) Door Hanger 3.01.23 (196 KB) Postcard 8.30.23 (965 KB) Doorhanger 8.30.23 (751 KB)