Michelson Water Recycling Plant Biosolids Lift Station and Sewer Pipeline Project
Summary
SCH Number
2025080488
Public Agency
Irvine Ranch Water District
Document Title
Michelson Water Recycling Plant Biosolids Lift Station and Sewer Pipeline Project
Document Type
NOE - Notice of Exemption
Received
Posted
8/12/2025
Document Description
The project involves upsizing an existing segment of IRWD’s sewer pipeline, installing new sewer laterals, retrofitting IRWD’s existing Stormwater Pump Station 3, upgrading IRWD’s existing Biosolids Lift Station, and completing site improvements for Stormwater Pump Station 3. All work would be conducted entirely within the boundaries of IRWD’s Michelson Water Recycling Plant (MWRP). The purpose of the project is to separate waste flows produced by the Biosolids and Energy Recovery Facility from stormwater flows to allow stormwater flows to continue being pumped to Pond C of the San Joaquin Marsh. The waste flows would continue to be pumped to MWRP’s primary treatment. The combined volume of stormwater and waste flows proceeding from the Biosolids and Energy Recovery Facility would not be increased as part of the project; rather, existing waste flows would be re-routed so they can undergo appropriate treatment. No expansion of the existing or former use of the Biosolids and Energy Recovery Facility is proposed, and the MWRP would continue to have the same treatment capacity upon project completion.
Sewer Pipelines and Laterals: An approximately 600-foot segment of an existing 8-inch sewer pipeline would be removed and replaced with a new 16-inch sewer pipeline, and an approximately 260-linear-foot segment of existing 6-inch sewer pipeline would be removed and replaced with a new 12-inch sewer pipeline. The new sewer pipeline would connect to existing sewer laterals that convey waste flows from the solids handling building, microturbine area, dewatering feed pump station, fats/oils/grease receiving station, and digester control building. In addition, a new 6-inch sewer lateral would be installed to convey waste flows from the odor control system (approximately 80 linear feet) to the new sewer pipeline. Portions of the existing sidewalk, curb, and gutter would be removed and replaced along the pipeline alignments. During construction activities, wastewater flows would be temporarily conveyed from upstream sewer cleanouts to the storm drain lateral or temporary storage tank.
Stormwater Pump Station 3: A portion of Stormwater Pump Station 3 would be modified to bifurcate the existing wet well, isolating the nuisance (sewer) wet well. During construction activities, stormwater flows would be temporarily bypassed to MWRP’s primary treatment. Work would occur during the dry season to minimize the need for bypassing.
Biosolids Lift Station: The existing nuisance pumps, piping, instruments, and controls in the Biosolids Lift Station would be replaced and upgraded. A new aluminum cover would be installed over the nuisance (sewer) wet well, and site improvements would be completed around the Biosolids Lift Station and Stormwater Pump Station 3. During construction activities, stormwater flows would be temporarily bypassed to MWRP’s primary treatment. Work would occur during the dry season to minimize the need for bypassing.
Contact Information
Name
Emily Le
Agency Name
Irvine Ranch Water District
Job Title
Environmental Compliance Analyst
Contact Types
Lead/Public Agency / Parties Undertaking Project
Phone
Email
Location
Coordinates
Cities
Irvine
Counties
Orange
Regions
Southern California
Cross Streets
Michelson Dr and Riparian View
Zip
92612
State Highways
I-405, SR 73
Airports
John Wayne Airport
Schools
University Park Elementary School, University High School
Waterways
San Diego Creek
Notice of Exemption
Exempt Status
Categorical Exemption
Type, Section or Code
Class 1, CEQA Guidelines Section 15301
Reasons for Exemption
The proposed project is exempt from the California Environmental Quality Act (CEQA) because the action involves the following: The minor alteration of the existing Stormwater Pump Station 3 and on-site sewer conveyance system involving negligible expansion of the existing use of these facilities and no expansion of the existing use of the Biosolids Energy Recovery Facility or MWRP. Class 1 exempts from CEQA review any project involving the operation, repair, maintenance, permitting, leasing, licensing, or minor alteration of existing public or private structures, facilities, mechanical equipment, or topographical features, involving negligible or no expansion of existing or former use, such as existing facilities of publicly owned utilities used to provide sewerage services. In addition, pursuant to Section 15300.2 of Title 14 of the California Code of Regulations, none of the exceptions to the use of a categorical exemption under CEQA are applicable.
Exempt Status
Categorical Exemption
Type, Section or Code
Class 2, CEQA Guidelines Section 15302
Reasons for Exemption
The proposed project is exempt from the California Environmental Quality Act (CEQA) because the action involves the following: The installation of replacement facilities, equipment, and appurtenances on the same sites as the existing infrastructure where the replacement infrastructure will have substantially the same purpose and capacity as the existing Stormwater Pump Station 3 and on-site sewer conveyance system with no increase in the production capacity of the Biosolids Energy Recovery Facility or the treatment capacity of the MWRP. Class 2 exempts from CEQA review any project involving replacement or reconstruction of existing structures and facilities where the new structure will be located on the same site as the structure replaced and will have substantially the same purpose and capacity as the structure replaced, such as the replacement or reconstruction of existing utility systems and/or facilities involving negligible or no expansion of capacity. In addition, pursuant to Section 15300.2 of Title 14 of the California Code of Regulations, none of the exceptions to the use of a categorical exemption under CEQA are applicable.
Exempt Status
Categorical Exemption
Type, Section or Code
Class 3, CEQA Guidelines Section 15303
Reasons for Exemption
The proposed project is exempt from the California Environmental Quality Act (CEQA) because the action involves the following: The construction and location of limited numbers of new, small facilities or structures and the installation of small new equipment and facilities in small structures within the existing Stormwater Pump Station 3 and along the existing on-site sewer and stormwater conveyance alignments. Class 3 exempts from CEQA review any project involving the construction and location of limited numbers of new, small facilities or structures; installation of small new equipment and facilities in small structures; and the conversion of existing small structures from one use to another where only minor modifications are made in the exterior of the structure. In addition, pursuant to Section 15300.2 of Title 14 of the California Code of Regulations, none of the exceptions to the use of a categorical exemption under CEQA are applicable.
County Clerk
Orange
Attachments
Notice of Exemption
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