Walnut Grove Project: Background

In Walnut Grove, the Sacramento Area Sewer District (SASD) owns and maintains the sewer pipes that collect wastewater from this community and currently convey it to the Walnut Grove wastewater treatment plant. This plant was built in the 1970s for the previous sanitation district that served this community.

In the past few years, the challenges facing the Walnut Grove wastewater system have reached a critical point, as the outdated treatment plant has not been able to keep up with new rules governing its operations.

To comply with these regulations, SASD undertook both short-term treatment plant improvements and long-term master planning efforts. The short-term measures were quickly implemented to address specific concerns raised by regional water quality authorities. The long-term master plan, meanwhile, required more serious study to identify and assess alternatives to the current treatment facilities.

In late 2003 and early 2004, SASD held public meetings in Walnut Grove to explain all the issues, discuss what had already been done to comply with regulatory requirements, and present future treatment alternatives. The treatment alternatives presented for public input included:

• Upgrading the existing treatment facility
• Piping the community's wastewater flows to the Sacramento Regional Wastewater Treatment Plant (SRWTP) in Elk Grove

Weighing the Benefits

During feasibility analysis of the options, it became clear that regulatory requirements would necessitate upgrading the existing treatment plant to a high (and expensive) level of treatment, called "tertiary" treatment, if discharging of treated wastewater was to continue at the current location. This meant that the first option would simply not be cost effective.

Piping the community wastewater flows to SRWTP, on the other hand, offered significant cost and community benefits:

• High treatment level: The regional treatment facility uses leading-edge technology, ensuring that treated wastewater meets strict regulatory standards.
• Less expensive: Of the treatment options considered, connecting to SRWTP was the most cost effective. While constructing new pipelines will require a significant initial investment by SASD, maintaining the Walnut Grove plant would require even more substantial outlays, both for the initial upgrades and continual operating costs.