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Active Projects
- WWTP Rehabilitation Project (Phase 2) Update
- Digester #2 Rehabilitation Project
- Miller-Sycamore Manhole Rehabilitation
- Miller-Sycamore Sewer Trunk Lines Rehabilitation
Location
450 Sycamore Avenue
Mill Valley, CA 94941
Phase Information & Update
The Waste Water Treatment Plant (WWTP) Rehabilitation Project (Phases 1 and 2) is 98% complete. The first phase of the WWTP Master Plan implementation began in April 2018 and was completed in 2020. Phase 2 started in 2020 and will be completed by the end of 2023 The primary goal in this $20+ million dollar program is to help ensure reliable treatment of wastewater, as well as compliance with regional, State, and Federal regulations. Numerous upgrades of major equipment and rehabilitation of existing infrastructure are key components of these two phases of this SASM construction program.
Completed Project Elements and Ongoing Work Activities
The following is a list of completed project elements and ongoing work activities that are progressing well and remain on schedule to be completed by November 2023:
• Headwork Building Belt-press Room Ventilation Modifications:100% complete.
• Rehabilitation of Secondary Clarifier Number 1: 100% Complete
• Rehabilitation of Secondary Clarifier Number 2: 100% Complete
• Hypochlorite Storage and Transfer System:100% Complete
• Rest Area Improvements: 100% Complete
• Digester Tank Number 1 Floating Cover Replacement: 100% Complete
• Cathodic Protection System (CP-1) Replacement: 100% Complete
• Trickling Filter #1 & #2 Media Replacement: 100% Complete
• Main Plant Switchgear Replacement:100% Complete
• Digester Tank #2 Floating Cover Replacement: 85% Complete
Notice of Construction & Parking Restrictions
450 Miller, 457 Miller, & Sycamore Park
October 2 – October 16
Maggiora & Ghilotti has contracted with the City of Mill Valley to perform sewer system improvements work under the Frontage Road Force Main Improvements Project. Upcoming work as part of this project consists of rehabilitating the sewer main from Miller Ave to and through Sycamore Park.
The rehabilitation work includes lining the existing sewer main with Cured in Place Pipe (CIPP) and rebuilding two (2) manholes on Miller Ave to accommodate the lining work. One manhole is on Miller in front of 450 Miller; the other manhole is at the back of the parking lot for 447 Miller. This project is an important health and safety improvement and will reduce the risk of a sewer spill and potential environmental impact.
The following is the work scheduled:
Mon 10/2 7AM – 5PM
Excavate and Demo Manhole 1A in 447 Miller parking lot.
Four Parking Spaces at the back of the parking lot will be closed to complete this work.
Tues 10/3 thru Thurs 10/5 7AM – 5PM
Excavate, Demo, and partially Rebuild Manhole 1 in front of 450 Miller.
The right lane in the eastbound direction on Miller Ave will be closed to complete this work.
Mon 10/9 7AM – 6PM (SYCAMORE PARK WILL BE CLOSED)
CIPP Line existing Sewer Main from 447 parking lot through Sycamore Park.
Also, parking nine spaces at the back of the 447 Miller parking lot will be closed to complete this work.
Wed 10/11 (NIGHT WORK) 8PM - 6AM
CIPP Line existing Sewer Main from 450 Miller to 447 Miller parking lot
The right lane in the eastbound direction on Miller Ave, curbside parallel on-street parking, bike lane and the back of 447 parking lot will be closed to complete this work.
Thur 10/12 thru Fri 10/13 7AM – 5PM
Complete the rebuild and backfill of Manhole 1 in front of 450 Miller.
The right lane in the eastbound direction on Miller Ave will be closed to complete this work.
Mon 10/16 7AM – 5PM
Complete the rebuild and backfill of Manhole 1A in 447 Miller parking lot.
Parking Spaces at the back of the parking lot will be closed to complete this work. About Cured in Place Pipe: CIPP is a common and cost-effective method to rehabilitate the existing sewer main with little to no excavation or street removal. This method provides a seamless lining of the existing main. During the rehabilitation pipe lining process, you may smell a chemical-like odor coming from your private drains. You may mitigate odors by pouring 1 gallon of water down all floor drains or any rarely used sinks/tubs/toilets to ensure that a water barrier is maintained in the traps.
Restricted Parking: Some spaces on the south shoulder of Miller Ave during the lane closure on Miller; and several 447 Miller Ave parking lot spaces during work in the parking lot as indicated in above schedule.
We apologize for any inconvenience caused by these construction activities, and we will be working as quickly as possible.
Project Updates are available at: www.cityofmillvalley.org/2023/2023-Sewer-Rehabilitation MVConnect is the City of Mill Valley eNewsletter sent twice a month directly to your inbox with project updates. You can subscribe at www.cityofmillvalley.org/675/MVConnect
If you have any questions or issues our field personal cannot resolve, please contact:
Maggiora & Ghilotti at 415-459-8640
or
City of Mill Valley Construction Manager, David Stier at 415-717-3496
Digester #2 Rehabilitation Project Update
The new cover will be constructed of Stainless-Steel (Grade 316) due to its high corrosive resistance material, similar in design of Digester #1 new cover. Material deliveries for Digester tank sludge piping, center diffuser, and floating cover have been received and inventoried. Overaa’s crew has remobilized and completed the piping installation in. The welding and assembling of the new floating cover started on June 13th . The new floating cover is expected to be commissioned and operational by mid-October 2023.
Photo of New Digester Gas Cover Being Lifted into Place.
Photo of Digester Tank #2 Interior Improvements
Photo of Digester Gas Cover installation at 85% Completion.
New Sewer Manhole in Sycamore Park ( 99% Completed)
A new manhole installation over a 30-inch diameter vitrified clay pipe (VCP) gravity sewer trunk line in Sycamore Park in support of SASM’s 2023-2024 Miller-Sycamore Line Rehabilitation Project was completed on August 25, 2023. This improvement will allow better access for staff during routine maintenance, cleaning, and inspection.
Exposed existing sewer trunk line
Newly installed manhole
Miller-Sycamore Sewer Trunk Lines Rehabilitation (Phase 1) (In Progress)
On August 21st, a contract amount of $389,376.00 was awarded to Maggiora and Ghilotti, inc., to perform Cured-In-Place-Pipe (CIPP) rehabilitation of 936 LF vitrified clay pipe (VCP) line through Sycamore Park and across Miller Avenue. This sewer trunk line is a critical component in the SASM’s collection system which transports over 70% of City of Mill Valley’s sewage flow to the SASM’s Wastewater Treatment Plant (WWTP) for processing. This 30-inch diameter gravity sewer trunk line built in the 1950’s era extends from Miller Avenue through Sycamore Park to Sycamore Avenue under the Arroyo Corte Madera del Presidio creek. This improvement will minimize the risk of failure and potential environmental impact. The CIPP installation schedule for the Sycamore sewer trunk line is October 9th and the Miller sewer trunk line is October 11th.