A $9.5 million upgrade to the San Luis Obispo wastewater treatment plant is underway to make the plant more energy efficient and ultimately reduce its carbon footprint.
The plant on Prado Road, now named the Water Resource Recovery Facility, treats 1.7 billion gallons of sewage from the city, Cal Poly and the county airport annually.
The city unveiled the new plans at a groundbreaking ceremony on Thursday.
The electricity needed to power the plant costs approximately $450,000 a year. The city will reduce that cost by about $157,000 in energy efficiency savings.
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The upgrade will also save $168,000 in maintenance costs.
The sprawling facility, which operates on 37 acres, is an intricate network of concrete pools and treatment areas that transform sewage into water safe enough to be released into the city’s creeks.
Many of the mechanisms used date to the plant’s last upgrade in 1994, but others have been in place for more than 60 years.
The city partnered with PG&E to facilitate the upgrades through a program that uses projected operational savings to finance the upgrades.
The project will eliminate the release of methane gas, a byproduct of treating solid sewage, by installing a cogeneration system to convert the gas back into electricity.
Several other areas of aged infrastructure, some as many as 40 years old, will also be replaced or upgraded. One such upgrade, to the plant’s headworks where raw sewage first enters the system, will significantly reduce the odor offset from the process.
The plant’s control system will also be upgraded to allow for treatment operators to more efficiently track and operate the various treatment processes.
The City Council approved the financing for the project in May 2013.
“The city is making the statement to everyone else to power down,” said Mayor Jan Marx.
The improvements are expected to reduce carbon dioxide emissions by one million pounds annually — the equivalent of planting 378 acres of forest, according to the city.
The public-private partnership between PG&E and the city is the first of its kind to improve energy efficiency at a city facility.
PG&E assisted with project development, design and implementation.
In the past, the utility company has partnered with several federal agencies, such as the Internal Revenue Service and the Federal Aviation Administration, but San Luis Obispo is the first non-federal project partnership.
“It helps the city in sustainability and ultimately helps our customers,” said Pat Mullen, PG&E regional director. “We are thrilled to be a part of this unique and progressive approach.”