Composting Food And Yard Waste Atop A Landfill
The City of San Diego (CSD) was composting up to 100,000 tons of green waste material per year using turned windrow technology. As food waste was being added as a new feedstock, and because of the contamination from their automated curbside collection process, the City wanted to evaluate in-vessel technology for the purposes of composting mixed green waste and food waste.
Ownership: City of San Diego
Location: Miramar Greenery, CA
Product: SG MOBILE® System with GORE® Cover
Input quantity: 45,000 TPY
No. of Heaps: 24 Heaps, 18 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 and Oxygen Control mode
Input material: Source Separated Organics (commercial, institutional, 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
THE SG SOLUTION
Pilot Scale Demonstration Project
Since food waste was added as a new feedstock, and because of the contamination from their automated curbside collection process, the City wanted to evaluate in-vessel technology for the purposes of composting mixed green waste and food waste. After several alternative methods were evaluated, the City chose to implement a SG MOBILE® System with GORE® Cover (covered aerated static pile) Pilot-Scale Demonstration Project in 2009.
Food Waste Composting; Compost a new feedstock – commercial, institutional and residential food waste.
Evaluate the ability to produce a high quality finished compost while controlling Odors, GHG Emissions, Leachate, Moisture, and Vectors.
Meet or exceed local, county, and state regulations.
Evaluate the operating capability and simplicity of the technology.
Develop model for the total cost to build and operate the composting technology.
The SG MOBILE® Systems on the San Diego Miramar Greenery Landfill
SG MOBILE® Outperforms Existing Windrow Turning Process
Of significant importance to the Pilot-Scale Demonstration Project was that the SG MOBILE® System with GORE® Covers process outperformed the existing windrow turning process for quality, time to manufacture and performance. In addition, the demonstration project validated the following:
Waterproof, breathable cover suitable for all SoCal climate conditions
Clear separation of stormwater from leachate
Small footprint (45K TPY on <3 acres)
Low energy costs (<2kw per ton processed)
Oxygen controlled treatment process
Conserve moisture during the composting process
Meet or exceed all government emissions standards
8-week treatment time
The IoT enabled Compost Control System is a secure plug and play solution that can be operated from any smart device from anywhere in the world, reducing the cost and complexity of installation and operation. Of additional note is the fact that Sustainable Generation delivered an all-electric cover winder machine for this project for the first time. Previous generation winders were diesel or gas powered.
This Pilot-Scale Demonstration Project, along with other positive results of the GORE® Cover’s performance at existing facilities in California, helped CSD to earn a $3 million grant from CalRecycle for this project in 2017.