Final Report: Recycling Process for Poultry Litter

EPA Contract Number: 68D99017
Title: Recycling Process for Poultry Litter
Investigators: Allred, Ronald E.
Small Business: Adherent Technologies Inc.
EPA Contact:
Phase: I
Project Period: September 1, 1999 through March 1, 2000
Project Amount: $69,988
RFA: Small Business Innovation Research (SBIR) - Phase I (1999) RFA Text |  Recipients Lists
Research Category: Hazardous Waste/Remediation , SBIR - Waste , Small Business Innovation Research (SBIR)


Generation of manure in the US in 1997 is estimated at 1.37 billion tons. Modern poultry production methods use wood chips, sawdust, peanut hulls, and other bedding materials, creating vast quantities of spent litter, feathers, and feces that require disposal, typically through land application within cropping systems. Nutrients contained in poultry litter include nitrogen (N), phosphorous (P), and trace minerals and metals (e.g. Cu, Zn).

Regulations restrict litter application rates to limit soil nutrients to at or below expected nutrient demands of particular crops. This prevents in-soil nutrient accumulations and subsequent environmental contamination due to runoff. Nitrogen and phosphorous are well-known contributors to eutrophication. Accumulation of these elements in waterways and estuaries results in overgrowth of plant species (e.g., algae blooms) and accompanying fish kills. Nitrate leaching into ground water poses a direct threat to human health. Because of pending new regulations, it is questionable whether land application of poultry waste as well as other types of animal wastes will continue to be an acceptable disposal solution in the long term.

Several potential technologies and solutions for the poultry litter and odor problem are being pursued including improved feeds, refeeding, odor control additives, anaerobic fermentation, biogas, composting, and catalytic conversion. Each of these approaches offers different benefits to greater or lesser extents. An extensive discussion of all issues related to poultry waste management can be found in the recent review by Williams et al. [1].

An innovative solution to the animal waste problem using recycling technology developed for complex mixtures of waste plastics was investigated in the Phase I program. This approach minimizes the amount of waste generated by recycling the bedding back to the turkey growers. When the recycled litter is no longer suitable for reuse as bedding, the recycled bedding is processed into valuable nutrient containing products. The core technology is a highly efficient tertiary recycling reactor using a closed system, which ensures full capture of environmental contaminants.

The long-term goal of Adherent Technologies is to develop a profitable commercial business capable of recycling poultry litter, through reuse or conversion into marketable secondary products, and thus eliminate or significantly reduce a severe waste management problem impacting the environment. The primary objective of the Phase I program was to develop the technical and preliminary economic data necessary to establish the feasibility of tertiary recycling for poultry litter and to identify design issues for a larger scale recycling system. The Phase I program was conducted with the North Carolina State University (NCSU) Animal and Poultry Waste Management Center (APWMC).

The approach taken in Phase I was to conduct large-scale pen studies of raising birds on recycled material and monitoring their performance (growth rate, mortality, bedding performance, etc.) and compare these values against a control group. The pen study provided a unique opportunity to acquire a large sample of well managed and documented material to validate the approach. The study also included an application to real world production regimes that is unusual for a six-month Phase I SBIR program.

Numerous secondary goals were also addressed during the Phase I program. Those goals included evaluating the conversion products from recycling turkey waste feedstocks; evaluating product resale markets; determining design requirements for a larger scale demonstration system including material preparation, feed and transport, product containment, and safety issues; and evaluating overall economics.

Experimental Procedures

Turkey litter from a previous growth study was used as the recycling feedstock for the Phase I study. Large white male turkeys had been reared on the bedding for 20 weeks at the NCSU APWMC. The litter was removed from the pens and stock piled for approximately 2 weeks before recycling for reuse as bedding material. Twelve thousand pounds of the turkey litter was processed in Adherent Technologies? mobile reactor and placed into turkey pens as bedding material for the turkey growth study. Four litters were used in the growth study:

  • Treatment No. 1 -- new pine shavings (same as previous growth study)
  • Treatment No. 2 -- turkey litter heat treated at low temperature
  • Treatment No. 3 -- 70:30 mixture of turkey litter processed at low and high temperature, respectively
  • Treatment No. 4 -- 95:5 mixture of turkey litter processed at low and high temperature, respectively

The litter treatments were placed in 36 floor pens in a randomized block design to provide 9 replicate pens per treatment. Each pen was approximately 60 ft3. There was one tube feeder and one bell-type waterer in each pen. Additional temporary feeders and waterers were used during the first two weeks.

Thirty Nicholas Large White turkey hen poults were placed in each pen on day of hatch. Typical rearing techniques were used to rear the birds for a 14-week growth period. During this period, standard industry type rations were provided. Monensin was used for coccidiosis prevention up to six weeks of age. No other growth promotants, antibiotics, or ?feed additives? were used. Feed consumption, by pen, and mortality were monitored. Birds were weighed individually at 6, 10, and 14 weeks of age. Period and cumulative feed conversion ratios were calculated.

Litter was sampled for nutrient content (N, P, Cu, and Zn) for the treatment litters at the beginning of the study and at 6 and 14 weeks of age. Litter was sampled for total hetertrophs and coliform bacteria at the beginning of the study and at Weeks 6 and 14. The litter treatments were also sampled for Salmonella sp and Campylabacter sp at the beginning of the study and at Week 14. Ammonia levels were determined in 3 pens per treatment at the beginning of the study and at Weeks 6 and 14.

Summary/Accomplishments (Outputs/Outcomes):

The characteristics that are important for the bedding material include ?fluffability,? odor absorption capabilities, moisture retention properties, sterility, lack of odor after processing, and effect on bird growth/performance. The recycled bedding did not have the pungent odor of the feed material. The turkey growth study showed no differences in body weights, cumulative or period feed conversions, or mortality for the different litter types.

There were no coliforms, Salmonella sp. or Campylobacter sp. detected in the new pine shavings or heat-treated litter at the beginning of the study. At the end of the study, there were no differences in total hetertrophs for any treatment. However, Treatment 1, the new pine shavings, had significantly higher levels of coliforms than any of the heat-treated litter. There were also no differences among treatments for levels of Campylobacter sp. One composite sample for Treatment 3 had detectable levels of Salmonella sp. None of the other samples for Treatment 3 or any other treatment had detectable Salmonella sp. levels.

It was concluded by NCSU personnel that recycling of previously used turkey litter produces a bedding equal to new pine shavings as a litter material for the rearing of commercial market turkeys.

Economic Analysis
Three types of products (e.g., solids, liquids, and gases) are produced by recycling turkey litter with the Adherent Technologies? tertiary recycling reactors. The solid product has three identified potential uses: as a bedding material, as an organic fertilizer, and as an activated carbon source. The liquid and gaseous products may be suitable for use as a liquid fertilizer.

A preliminary economic evaluation was performed to potentially gain equity investment and financing for a poultry litter tertiary processing operation specific to the NC region. The analysis was performed for designing, building, and operating a poultry litter processing plant over a 10-year period. All aspects of the operating process were included, which provides a foundation for a preliminary business plan. Sensitivity analyses to evaluate the effects of model inputs against the output parameters of profit, return on investment, present and future worth, etc., have also been performed. Results show that a plant processing 10 tons/hr, located in NC, within a 50-mile radius of the projected feedstock, would be a profitable facility with a rate of return exceeding 46% ($14/ton profit), and an annual before depreciation cash flow of $1.12 million.

The preliminary model analysis is considered to be very conservative because no business growth was included and the minimum value for the reclaimed products was used. Even with these conservative numbers, the economic analysis indicates that the proposed business will be a profitable operation provided a quality organic-based bagged fertilizer product can be developed. In addition, the proposed process has the potential to save valuable natural resources (eliminating environmental contamination) by reducing land application of poultry litter. Based upon our preliminary economic analysis additional studies into maximizing the value of the products generated by the process reaction are warranted.


Results of this feasibility study for using recycled poultry litter as bedding material for raising new chicks show that the recycled litter is equivalent to the new pine shavings currently used. An economic analysis of a recycling business based in North Carolina shows that this approach is profitable providing a high-quality organic-based bagged fertilizer can be produced after three uses as bedding material.

Technologies and services that capture nutrients from poultry and other animal wastestreams for profitable utilization will encounter significant demand in the marketplace. Effective use of these resources will satisfy public demands for clean soil and water resources, and satisfy the producers? need for efficient removal and reclamation of biological waste streams.

The recycling technology proposed by Adherent Technologies, combined with a strong commitment to site-specific, economically viable and environmentally beneficial solutions, provides a means for reducing poultry producer reliance on application fields. Reliance on these systems has resulted in increased operating, environmental, and financial risks for producers. With stronger regulation of odor containment, nutrient application, and mortality disposal pending, these risks and the costs of waste handling will continue to increase. In addition, the success of the pen study should lead to rapid industry acceptance and commercialization of the poultry litter recycling technology.

Future Work
Results of the Phase I program show that tertiary recycling technology is an effective means for processing poultry litter for reuse as bedding material. Commercialization of this technology depends on acceptance by the growers and formulating a high-quality organic-based fertilizer or other valuable product for resale after the litter has been recycled several times. Future research will focus on addressing these issues along with designing a commercial facility and development of a business plan.

Supplemental Keywords:

Poultry litter, recycling, waste management, animal waste, organic fertilizer., RFA, Scientific Discipline, Waste, Sustainable Industry/Business, cleaner production/pollution prevention, Sustainable Environment, Environmental Chemistry, Technology for Sustainable Environment, Engineering, Hazardous, hazardous waste management, recyclable design, animal waste, catalysts, hazardous waste, hazardous organic contaminants, recycling, organic chemicals, catalytic tertiary conversion process, agriculture