Producing biomass: Biomass types: Animal waste: Poultry litter
Spent poultry litter—a mix of excreted manure, water, spilled feed, feathers and bedding material—can be converted into biogas (a renewable energy source consisting mostly of methane and carbon dioxide). Biogas can be burnt to generate electricity and heat, upgraded into a transport fuel (biomethane) and can yield other useful products.

Benefits of using poultry litter for bioenergy

Poultry litter has traditionally been disposed of by spreading it on the land as fertiliser or by sending it to landfill. It is also used as potting mix, and is occasionally fed to cattle.

With more stringent legislation controlling the spreading of litter on land, and the rising cost of energy, more attention is being paid to extracting more value from litter (and other by-products from the chicken meat industry, such as hatchery waste and processing waste) in the form of energy.

Methane can be captured from the decomposing manure and converted to electricity or heat, or the waste can be used to produce liquid fuel.

Using poultry litter to create bioenergy has many benefits, such as:
  • reducing the amount of waste that needs to be disposed of
  • recovering energy from waste
  • reducing odour problems
  • reducing potential for groundwater contamination
  • giving a use to waste that previously had little or no market or environmental value
  • reducing water use by reusing washing water for the plant/lagoon
  • generating income from waste/diversifying income sources
  • moderating the impacts of commodity prices
  • killing harmful bacteria, flies and weed seeds normally in and around manure
  • converting organic nitrogen into a form available to be used by plants.
Some of these benefits are described in the 2008 US Government paper Livestock waste-to-bioenergy generation opportunities [PDF 322 KB, page 7941–2].

Evaluating the economics

To work out whether producing bioenergy from poultry litter is appropriate for your business, it’s important to know:
  • how much waste your poultry operation produces
  • the nutrient content of the litter
  • how much energy could be produced from the litter.


The economics of the following plants are analysed in the 2013 RIRDC report: Conversion of waste to energy in the chicken meat industry
  • farm-scale anaerobic digestion plant
  • farm-scale combustion plant
  • centralised large-scale plant-waste to energy plant
  • centralised large-scale anaerobic digestion plant
  • centralised large-scale combustion plant with electrical generation.


The characteristics of spent litter, including the nutrient content, are also analysed in the report, and case studies, regulation, legislative constraints and technologies are described.



The nutrient and fuel value of poultry litter, and its limitations as a fuel source, are also described in The uses and management of poultry litter (2010, not free).



RIRDC’s 2008 Assessment of methane capture and use from the intensive livestock industry:
  • explores the viability of methane capture and use systems for the Australian intensive livestock industry
  • reviews existing manure methane systems from intensive livestock industries operating within Australia and overseas
  • presents technologies that are best suited for capturing methane in the Australian context.
Some projects will only be viable if they also sell the dewatered, digested solids produced as a by-product.

Large, intensive livestock operations may be able to partner with nearby coal-fired power stations or cement works for co-combustion (where the waste would be burned with coal).

How much poultry waste is produced?

National production is estimated at 1.2 million tonnes a year, plus or minus 20%, according to the 2013 RIRDC report, Conversion of waste to energy in the chicken meat industry.

At the farm scale, the amount of waste depends on factors such as litter depth and frequency of disposal. Chandala Poultry in Gingin, Western Australia, is designing a system to convert chicken litter (manure and bedding) to biogas, and then to heat and electricity. The 1.7 million birds supplied for meat each year produce 3000 tonnes of waste a year.

Converting poultry litter to bioenergy

Poultry litter can be turned into bioenergy through two processes.
  • Biological processes:
  • Thermochemical processes:
    • use heat or chemicals to carry out pyrolysis or gasification
    • produce biogas, hydrocarbon fuel (bio-oil) and charcoal.
These processes are described in more detail by the Victorian Government, and in great detail in the 2013 RIRDC report: Conversion of waste to energy in the chicken meat industry and in the 2008 US Government paper, Livestock waste-to-bioenergy generation opportunities [PDF 322 KB].

Contacts

Geoff Sondergeld

Darling Downs Fresh Eggs

24 Tummaville Road, Pittsworth, QLD 4356,
Phone: 07 4693 5173

geoff@fresheggs.com.au