Anaerobic Digestion & Composting Collocation

Ownership: Santa Barbara County, California, USA
Location: Goleta, California, USA
Product: SG MOBILE® System with GORE® Cover
Input Quantity: 300 tons per day of digestate residuals
No. of SG MOBILE® Systems: 4 heaps, 3 covers, 25 ft. x 20 ft. x 8 ft. each
Treatment Time: Primary Phase for 21-28 days
Aeration: On-grade pipe
Control Parameters: Programmable Sequence Mode
Input Material: Anaerobic Digestate Residuals
Equipment: Conveyance System, Front End Loader, Mobile & Stationary Screening
End Product: High-Quality Finished Compost

Project Overview

In 2022, the Anaerobic Digester Facility (ADF) owned by Santa Barbara County commenced operations to produce renewable energy from the organics fraction of Municipal Solid Waste (MSW), which has been processed and recovered at their MRF located at the County’s Tijiguas Landfill. In the ADF, these organics underwent a 28-day digestion process, during which 50% were cycled back to the beginning of the process. The remaining 50% were directed to an open windrow process for supplementary composting. The ultimate goal was to refine the digestate residuals into premium-quality, salable compost. Due to site constraints concerning odor containment, stormwater management, and litter control linked with open windrow composting methods, management needed to retrofit the open windrow operation with technology that would eliminate odors and increase process control. With odor reduction being the most pressing issue, our solution, SG ADVANCED COMPOSTING™ Technology featuring the SG MOBILE® System with GORE® Cover, known to reduce odors by greater than 95%, was selected for a pilot study.

During a side-by-side technology evaluation, SBC compared the SG MOBILE® System with GORE® Covers against the existing open windrow technology. Additionally, a separate composting vendor set up a pilot system adjacent to the SG pilot, but could not perform and meet the demonstration requirements. Ultimately, SBC selected SG’s solution to meet the performance objectives. In addition to solving the odor issue, our system is part of the solution to the site’s stormwater issue, providing clear separation of stormwater from leachate. During the cost analysis portion of the study, any competing technology would require a roofed solution over the entire compost operation at a tremendous cost. This comparison highlights the cost-effectiveness and superior environmental control of our technology.

Pilot Study

In February 2023, Sustainable Generation, LLC delivered an SG MOBILE® System demonstration unit. Within days of the delivery, the unit was powered up and began composting digestate. Multiple batches were run as part of the overall study to prove the objectives for:

Within 90 days from setup to tear down, SG performed multiple batch tests to determine the proper mix recipe and prove that the SG MOBILE ®System would eliminate odors, which included a third-party independent test for odors and VOC emission reduction compared to the existing open windrow process.

• 97.5% Odor Reduction
• 98% VOC Emission Control
• Clear separation of stormwater from leachate during adverse weather events, including atmospheric rivers from the Pacific Ocean
• PRFP temperatures were easily met (3 days at 131°F)
• Stable and mature final compost

These outcomes validated the SG MOBILE® System’s capabilities, proving its efficiency in transforming organic waste into high-quality compost while mitigating environmental impacts.

Full-Scale Implementation

In less than a year after initially engaging with SG, SBC had its new full-scale 20-windrow SG MOBILE® System designed, constructed, commissioned, and operational. The site demonstrates a significantly improved environment, with effective litter control measures and reduced waste accumulation. Additionally, this system has dramatically reduced the ecological footprint while increasing productivity. Notable achievements include successfully resolving site challenges, reducing odor, and improving stormwater runoff control.

This project marks SG’s quickest Public Project implementation, transitioning from a pilot to full-scale deployment in just ten months. Santa Barbara County officials played a crucial role in this success by swiftly removing roadblocks and making timely decisions. This rapid progress highlights the power of the SG MOBILE® System and our dedicated service team, demonstrating the impact of effective collaboration with a proactive project owner.