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San Diego County - Otay Composting Facility

Composting Food And Yard Waste Atop A Landfill

Republic Services, under contract with San Diego County, explored solutions for the County to accept food waste feedstock from the greater San Diego region, including Chula Vista and Carlsbad. The facility needed to meet regulations set forth in SB1383, AB1826, and local air pollution regulations for VOC and odor controls given the location of the landfill, which was under a mile away from a residential development. Another requirement was for the selected technology to be portable since the facility would be located on top of an active landfill.


  • Ownership: Republic Services

  • Location: Otay Landfill, San Diego County, CA

  • Pilot: 2018 (4 heaps, 3 covered)

  • Facility Commissioning: 2022

  • Product: SG MOBILE® System with GORE® Cover

  • Input quantity: 60,000 TPY

  • No. of Heaps: 32 Heaps, 24 covered, 100 ft. x 26 ft. x 12 ft. each

  • Treatment Time: 8 weeks in 3 Phases

  • Aeration: Above ground

  • Control Parameters: Proprietary California Compliant Control mode

  • Input material: Source Separated Organics (residential food waste) / Yard Waste (tree, grass and leaves)

  • Equipment: Pre-Treatment (Grinders) / Front-End-Loader(s) / Electric Powered Winder / Mobile Screen

  • End Product: High Quality Finished Compost


Pilot Scale Demonstration Project

Republic Services evaluated various composting solutions and decided to initiate a pilot program with a four pile SG MOBILE® System with GORE® Cover utilizing SG SOLARTM Power Units in 2018. The pilot project confirmed the following for Republic Services:

  1. The SG MOBILE® System is scalable for food waste composting and capable of handling up to 50% food waste feedstock without compromising process control.

  2. The off-grid solution using SG SOLARTM Power Units is a great solution to maintain portability while reducing the overall carbon footprint of the facility.

  3. The SG/GORE system consistently meets or exceeds local, county, and state regulations for VOC, GHG, and odor emissions.

  4. The operating capability and simplicity of the SG Compost Control System is unmatched in the industry.

The IoT enabled SG Compost Control System is a secure plug and play solution that can be operated from any smart device, anywhere in the world, thus reducing the cost and complexity of installation and operation. Of additional note, Sustainable Generation delivered an all-electric cover winder machine for this project, further reducing the carbon footprint of the facility.


The SG MOBILE® Systems on the Otay Landfill


SG MOBILE® System Proves Efficacy, Scalability, & Wins Awards

The Otay Composting Facility by Republic Services was expanded to 16 piles, commissioned in April 2022, with a second expansion of 16 more piles (for a total of 32) in late 2022. The SG MOBILE® System with GORE® Covers proved that it meets, or exceeds, existing environmental regulations while processing the growing volume of feedstock from the greater San Diego region.

The SG SOLAR Power Units provide enough power for the entire facility - everything from blowers and temperature probes used in the composting process to air conditioning in the facility's office – saving costs by eliminating the need to provide additional infrastructure.

The facility accomplished each of the goals set out by Republic Services and, as a result, was recognized in the industry by being awarded the NWRA 2022 Organics Management Facility of the Year Award.

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