The total U.S. agricultural plastics generation is estimated to be 816 million pounds. The options for farmers to recycle these used plastics have been neither robust nor sustainable because of the soil contamination level. However, one viable and economic opportunity is for the recovery of irrigation drip tape.
By Gene Jones
Plastic products and packaging have become an integral part to all aspects of farming. Plastic films are used to wrap forage, to cover greenhouses, and to mulch fields of vegetables and fruits like tomatoes and strawberries (see Figure 1). Most nursery containers are made of plastic, as are the containers used for pesticides and dairy sanitizers. Irrigation and maple tubing are plastic. The list goes on. Much of it has been burned in the field, generating dioxins and other pollutants, or dumped in some out of the way place on the farm. In addition, plastics are buried in landfills. The options for farmers to recycle these used plastics have been neither robust nor sustainable.
I have been working on the subject of agricultural plastics management since 1999 when the Southern Waste Information eXchange, Inc., a 501(c)(3) non-profit organization, was asked by the Florida Department of Environmental Protection to conduct a Technical Advisory Group or TAG on the subject of dealing with the large volumes of agricultural film mulch being generated in Florida on an annual basis. The following summarizes some of the background information on agricultural plastic use/generation as presented by Arthur Amidon of Amidon Recycling at that TAG in 1999.
The total U.S. agricultural plastics generation is estimated to be 816 million pounds or 408,000 tons. This includes horticultural film, irrigation tubing, livestock plastics, miscellaneous row covers, nursery containers and pesticide containers. Of the total 816 million pounds, 126 million pounds is estimated to be horticultural film plastic. Nursery containers are estimated to make up over half of all U.S. agricultural plastic—422 million pounds.
The various management methods for this waste stream includes:
• Burning or burial onsite (legally and illegally)
• Waste-to-Energy Incineration
Florida waste plastic film mulch is estimated to be 25 million pounds per year of mulch and as much as 10 million pounds per year of drip tape. This mulch film is approximately 1/3 of all mulch film used in the U.S. Additionally, Florida uses 6 to 8 million pounds (1/4 of U.S. use) of greenhouse and nursery film annually. Add up these figures and you are in the neighborhood of 40 million pounds/year in Florida alone.
Very little, if any, of this material is recovered for recycling. It is either burned in small piles in the field (after the used mulch is gathered by hand laborers who pile it at the end of each crop row) or buried in Class I and III area landfills (see Figure 2).
As stated from Amodon’s presentation, the bulk of agricultural film mulch in Florida is reported to be managed via open burning at the end of the growing season. This is allowed through Florida Administrative Code 403.707 (2)(e):
(e) Disposal of solid waste resulting from normal farming operations as defined by department rule. Polyethylene agricultural plastic, damaged, non-salvageable, untreated wood pallets and packing material that cannot be feasibly recycled, which are used in connection with agricultural operations related to the growing, harvesting, or maintenance of crops, may be disposed of by open burning if a public nuisance or any condition adversely affecting the environment or the public health is not created by the open burning and state or federal ambient air quality standards are not violated.
The allowance of open burning of the material in the field, though it may save farmers disposal fees, has led to a disincentive of the recycling of this material. It should also be noted that health and environmental implications to the burning of the material in a non-controlled environment might lead to potential negative environmental and human health impacts.
Trying to Solve the Problem
So what is the issue with the recycling of agricultural plastics? Why has the recycling of agricultural film mulch been so unsustainable? The answer comes down to contamination level—mainly soil. Take a look at the bales of Ag film in Figure 3. These are bales that are generated by a tomato farmer that is having his film recovered for recycling overseas. These types of bales are produced from a Bacca Baler or Big Foot Baler that are on the market to bale Ag film in the field. The bales weigh in the neighborhood of 1,250 pounds. What looks like all recovered film is actually on average about 60 to 70 percent soil and moisture.
Most agricultural film mulches are manufactured with a micro pattern for rigidity purposes (see Figure 4). The micro pattern acts like a suction cup causing moisture and associated soil to adhere to the film. Figure 5 is a view under a microscope of a sample of Ag film collected from the field. Notice the square pattern on the film and the crystal particle. The crystal particle is a grain of sand. That is how small the micro pattern is.
The soil contained in the recovered film causes havoc with shredding equipment. During a trial with Suwannee American Cement (SAC), 3,500 tons of baled Ag film were sent for an alternative fuels trial. The film was shredded in a primary dual shaft shredder, then fed into a single shaft secondary shredder with a 2 inch screen to be pneumatically injected into the kiln. Ag film has great BTU value but not with the amount of soil contamination that was discovered to remain on the film. The film burned at such a high temperature (> 2,500F ) and it burned much cleaner than coal, which is traditionally used by most cement kilns. The amount of soil contained on the film forced SAC to change out its shredder blades at the end of every week at the cost of $16,000. After the trial was over, the SAC said “Thanks but No Thanks” to any more Ag film. Lesson learned the hard way.
More Obstacles for Ag Plastics Markets
For those materials being recovered from the field, the majority was being sent overseas to China, Vietnam and Malaysia. All three of these countries have put a stop to taking agricultural plastics recently. As a result, the U.S. has an over-supply of Ag plastics with no viable market. Most of the material is now ending up in the landfill, or even worse, being burnt in the field.
On the Bright Side
One viable and economic opportunity is for the recovery of irrigation drip tape. I have been working with some large growers in Florida and an equipment developer to figure out the economics of recovering irrigation drip tape. I am putting together a cooperative to get farmers to pool their efforts to collect irrigation drip tape and pull the tape from the fields by rolling the fill up. Once it is rolled up, we can arrange for transportation to collect the film, which then would be cleaned and sold. The farmers would benefit from the sale of the film either by direct financial support from the sale or a credit back to offset the purchase of new film. The material is typically LDPE and can be recovered with significantly reduced amounts of soil contamination (see Figure 6).
The economics from what we have learned led us to make an effort to recover more irrigation drip tape from farmers. It is just a matter of convincing them to pull the drip tape separately from agricultural mulch film. Hopefully we will be successful in our efforts. Stay tuned.
Gene Jones, the Executive Director of the Southern Waste Information eXchange, Inc. (SWIX) (Talahassee, FL), the organizer of the Agricultural Plastics Recycling Conference & Trade Show, which is tentatively being planned for 2020 in San Diego, CA (http://AgPlasticsConference.com). The event is designed as a networking forum bringing Farmers, Nurseries, Agricultural Plastic Manufacturers, Recyclers and Government Officials together to discuss the solutions to the landfilling and open burning of waste agricultural plastics. Gene can be contacted at (800) 441-7949 or via e-mail at firstname.lastname@example.org.
Agricultural Films Market By Applications & Polymers – Global Trends 7 Forecasts to 2017 Prepared by Markets and Markets: www.marketsandmarkets.com/Market-Reports/agricultural-mulch-films-market-741.html.