Completion of the Main Plant Rehabilitation Project:
The District, in 2010, conducted a condition assessment that found the main wastewater treatment plant well maintained, although considerable signs of aging were apparent. Due, in part, to the close proximity to the San Francisco Bay, which creates a very harsh and corrosive environment for the treatment plant’s machinery and electrical components, the main plant’s equipment was at or beyond its expected useful life and below efficient energy, environmental, and safety standards.
The main plant was last rehabilitated in the early 1980s, with the original primary plant dating back to the 1960s. It was anticipated that routine maintenance costs would rise to significant annual expenditures. The Board of Directors of Sanitary District No. 5 of Marin County, therefore, authorized a report for the Preliminary Design of the Main Plant Capital Rehabilitation and Replacement Project that was completed in 2011. Upon receipt of that report the District then deemed the Main Plant Rehabilitation (MPR) Project appropriate for the District's needs, and construction began in June, 2012, and was completed in October, 2014.
Update as of November, 2015
On October 22, 2014, the District filed a notice of completion on the MPR Project completed by low bidder Auburn Constructors, Inc. (ACI), of Sacramento, CA. ACI began construction on June 11, 2012. The total bid amount for the construction of the project was $8,922,300. The total paid to Auburn Constructors was $9,636,402 which amounts to an 8% increase due to change orders encountered during construction. Major change orders included: removal and replacement of the primary and secondary clarifier sludge skimming equipment, solids dewatering automation, replacement of 2 check valves on the critical wet weather pumps, replacement of the main switch board receiving PG&E power, and radio communications from remote pump stations to the Main Plant.
Overall, the project was a huge success for the District. The District remained well within permit limits for the duration of construction in spite of the multiple shutdowns and pump-arounds required throughout the project. SD5 and Auburn Constructors staff worked closely together on the project, producing positive results and with no accidents. In the end, Sanitary District No. 5 of Marin County was left with an up-to-date, reliable and efficient treatment plant, which will serve the community for many years to come.