An Integrated System of Organic Food Production and Urban Food Waste Recycling Using On-Farm Anaerobic Digestion and Fertigation

1998 Annual Report for LS98-090

Project Type: Research and Education
Funds awarded in 1998: $142,623.00
Projected End Date: 12/31/2002
Matching Non-Federal Funds: $138,978.00
Region: Southern
State: Florida
Principal Investigator:
Anne Barkdoll
Full Circle Solutions, Inc.

An Integrated System of Organic Food Production and Urban Food Waste Recycling Using On-Farm Anaerobic Digestion and Fertigation


Organic farms are concerned with procuring organic soil amendments while communities need to expand recycling. Food wastes are a rich source of plant nutrients and energy. Generally these wastes are disposed of in landfills where they produce leachates and volatile emissions. Anaerobic digestion of food wastes eliminates these problems and provides an inexpensive source of fertilizer and energy. This is important to organic farmers who pay five to ten times more per pound of nitrogen compared to conventional farmers and have few sources of organic, liquid fertilizer. This three-year project will use anaerobic digestion to recycle urban food waste on-farm.

1) Implement an integrated system to recycle nutrients and organic matter through on-farm anaerobic digestion of urban foodwaste;
2) Evaluate liquid fraction fertigation methods with regard to biofouling;
3) Test the agronomic response to the liquid fraction;
4) Determine the economic feasibility and logistics of this concept from waste collection to nutrient reuse;
5)Educate farmers, waste haulers, environmental regulators, restaurant owners and extension personnel about this concept.

Possum Hollow Farm is currently receiving food waste and recycling it using anaerobic digestion, fertigation of the liquid fraction and land application of the solid fraction. Field trials comparing growth responses to the digester liquid fraction and other organic fertilizers are being conducted at two additional farms and one research farm.

The system has been producing a fertilizer with a nitrogen content of approximately 20 pounds nitrogen per 1,000 gallons of digester liquid. The fertilizer has proven effective but can “burn” transplants if overapplied. Additional field trials will be done in the coming year. Irrigation evaluations will still need to be conducted. The financial analyses are underway. A field day will be conducted next spring.

The project results have been presented at three conferences in the past year. Several hundred people were given a demonstration of the recycling system last spring during a farm tour. The project was featured in the local paper (The Gainesville Sun), the AP wire service, The Wall Street Journal, Biocycle, and Waste News.

This practice can provide a new source of liquid, organic fertilizer, create a new revenue source for farmers in the form of on-farm tipping fees, and divert a significant proportion of food waste from landfills.


Gina Hawkins

City of Gainesville, Solid Waste Division
Lois Milton

Bellevue Organic Farms, Inc.
Bill Edwards

Cherry Tree Recycling
Rosie Koenig

Rosie's Organic Farm
Mickey Swisher

Univ. of Fl. Family, Youth, Community Sciences
Sally Palmi

Alachua County Public Works, Waste Management
Dorota Haman

University Of Florida, Agricultural Engineering
Marty Mesh

Florida Certified Organic Growers and Consumers
Joe Durando

Possum Hollow Farm
Jerry Kidder

University of Florida, Soil Science
Alan Hodges

University Of Florida, Food and Resource Economics
David O'Keefe
Full Circle Solutions, Inc
Gainesville, FL 32641
Office Phone: 3523739313
Cassel Gardner

Florida A&M University
O.S. Mbuya

Florida A&M University
Gary Brinen

Univ. of FL., Alachua County Extension Service