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Converting Onion Waste

Gill Onions, LLC and Rio Farms, LLC

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Founded in 1983, Gills Onions is a family-owned and operated grower and food processor with the most innovative fresh-cut onion operation in the world. We process up to a million pounds of onions daily, generating on average 250,000 pounds of onion waste at our Oxnard plant. Gills Onions maintains an aggressive strategy to minimize its environmental footprint while ensuring the safety and highest quality of our products. As part of this strategy, in 2009 we adopted an ambitious zero waste goal. To move closer to this objective we implemented a comprehensive recycling program and expanded waste reduction initiatives through green procurement and employee engagement. Additionally, since 2009 we use onion waste (peels, tops and tails) to produce ultra-clean electricity onsite that provides 100 percent of the plant’s base load electricity. These efforts allowed Gills Onions to achieve 99.6 percent diversion rate as of January 2013.

Expanding our initiatives to the growing operation (Rio Farms) provides a tremendous opportunity for the Gill Family of companies to reach internal waste reduction goals. At the field level, onions are harvested mechanically. Throughout the years, we have made critical adjustments to our machinery, reducing the amount of onions accidentally left unharvested. Through our sorting and grading process our machinery and staff carefully separate out culled onions that do not meet market standards and are waste. The previous solution was to sling the onion waste out to the surrounding fields we farmed, however this solution created a host of problems for us; soil acidification, offensive odors from the fields, growth impairments of our commodities just to name a few.  

Starting in the year 2000, Rio Farms discontinued spreading the culled onions on our fields and started a composting program. The compost consists of all regionally-sourced ingredients including: culled onions from our own operations spent mushroom mulch, grape pomace from wineries, green waste and gypsum.  In addition to serving as a sink for other companies’ waste product and our own, creating compost helps up improve soil quality by increasing organic matter, feeding and restoring soil microbial populations, increasing water and nutrient holding capacity, slowly releasing an organic source of nutrients, and suppressing plant pathogens.

Our objective is to convert 100% of our culled onion waste in the King City region to valuable compost, used as a soil amendment.  We also have an objective to educate others about the innovative programs developed by Gills Onions and Rio Farms.  We feel our example provide a viable pathway for others to follow- helping to shift the perception of waste from a nuisance to a valuable resource.

Activity 1

Divert Onion Culls to Valuable Soil Amendment – Rio Farms, LLC

In 2013 we plan to:

  • Continue windrow composting operations on 7 acres we have taken out of production
  • Divert 100% of our culled onion waste at the field level – approximately 5,000 tons
  • Create approximately 40,000,000 pounds (20,000 tons) of compost
  •  Spread compost on farming fields to improve soil health
  • Consider other ingredients that may help reduce waste elsewhere and further improve soil quality.
  • Analyze soil tests to assess how compost program is benefiting soil organic matter
  • Adjust harvesting machinery to reduce onions left in field
  • Adjust sorting and grading machinery to reduce damage to onions

Start and delivery dates:

  • August 2013 – start harvesting and sorting onions
  • September – December 2013 – culled onions brought to pile and mixed with green waste to reduce moisture content and start composting process
  • November 2013 – March 2014 – spread created compost onto fields
  • Ongoing – educate others about the benefits of composting at regional and state-level conferences
  • Ongoing – advocate for food safety regulations that approve of reasonable use of composted materials

Activity 2

Disseminate information about our innovative waste management programs
Gills Onions Advanced Energy Recovery System (AERS)  and Rio Farms composting programs are two great examples that prove it is possible to use large amounts of agricultural and food waste to produce clean energy and valuable soil amendments. Gills Onions’ AERS can be used as a model for managing agricultural/food waste and distributed renewable industrial energy in California and the world. In California, nearly 430 million tons of food processing waste is produced each year. A significant amount of this waste stream could be converted into bioenergy using the technological innovations of the AERS waste-to-energy system. Processing waste onsite to generate renewable, emissions-free electricity reduces greenhouse gas emissions and disposal costs.

We feel our examples provide a viable pathway for others to follow- helping to shift the perception of waste from a nuisance to a valuable resource.  By educating and sharing our stories we can help the industry stay ahead of regulatory mandates, we may reduce duplicate work, find efficiencies, and potentially create larger partnerships or programs shared between companies. 

Rio Farms and Gills Onions is committed to sharing the knowledge and helping lead the industry in sustainability solutions by allowing staff to participate in speaking engagements and to sit on various boards in 2013. Moreover, we will participate in public events and speaking engagements when asked. Additionally we plan to host tours of our Oxnard Facility and King City compositing sites to showcase these examples of successful ways to dealing with our waste stream in a cost efficient and environmentally responsible way.

Start and delivery dates:

  • January - June 2013: Advocate for waste reduction strategies as member of California Department of Food & Agriculture Climate Change Adaptation Consortium for Specialty Crop Growers
  • August - November 2013: Help plan topics and line up speakers including topics on waste and recycling for the Sustainable Ag Expo held in Monterey County
  • Bi-monthly - Coordinate and attend meetings for the Monterey County Sustainability Working Group.  This group brings together sustainability professionals working in the growing and shipping industries in the Salinas Valley.
  • Monthly - Serve on the board of Directors  for the Grower-Shipper Association of Central Coast
  • Quarterly – Attend the California League of Food Processors meetings to discuss environmental compliance and new regulations
  • Ongoing – Attend trainings hosted by local agencies such as the UC Cooperative Extension, Monterey County Department of Public Health etc.