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Bioreduction: developing an alternative method to store fallen stock prior to disposal

Title of Experiment: Bioreduction: developing an alternative method to store fallen stock prior to disposal

Date planted: February 2007

Contact: Dr Prysor Williams

Funding sources:Welsh Government, Hybu Cig Cymru – Meat Promotion Wales, British Pig Executive, National Farmers Union Cymru, National Fallen Stock Company

Location: Henfaes Research Centre (lowland site)

Experimental Aims:

  • To evaluate the efficacy of  bioreduction as a system for the storage of fallen stock (dead livestock) prior to disposal in terms of
    a. Biosecurity
    b. Practicality / ease of use
    c. Capacity and how to improve rates of carcass degradation  
    d. Costs

Google Maps, 2013

Brief description

Since the EU Animal By-Products Regulations were implemented in 2003, farmers are forbidden from burying livestock carcasses. This has caused considerable animosity within the industry due to biosecurity concerns (carcasses are now collected by a centralised transport system, with vehicles visiting numerous farms), practicality issues (especially during times of heavy losses, e.g. during periods of bad weather), and costs. Hence there has been growing calls for an alternative system.

Bioreduction has been developed at Bangor University as such an alternative. The process involves placing livestock carcasses in a fibreglass vessel which contains water heated to mesophilic temperatures and is subject to active aeration. The moist, warm conditions mean the environment is conducive to bacterial breakdown of carcasses and hence there is a rapid reduction in the volume of waste that is ultimately sent away for disposal off-site. Any system that handles animal by-products must not lead to risk to the operator, livestock or the wider environment (e.g. in terms of disease or pollution). We have therefore monitored the fate of a number of bacterial and viral pathogens within a Bioreduction system, in aerosols generated and within the liquid waste. We have also monitored the system for odour, running costs, identifying practical improvements, etc. Our results indicate that Bioreduction is a safe and effective form of storing livestock carcasses prior to ultimate disposal.

We have collated the evidence gathered and have submitted a dossier to the European Food Safety Authority (EFSA) on the system via Defra. EFSA are the panel that validate the application of new technologies and if it is approved, then Bioreduction can be incorporated into amended EU regulations, and subsequently be available for industry use. The system has received interest from across the EU, North America, and the Far East. 


In addition to the funders, we have collaborated with the following:
Dr John McKillen and Irene McNair, Agri-Food and Biosciences Institute, Belfast
Dr Amie Adkin, Animal Health and Veterinary Laboratories Agency, Surrey
Dr Andrew Norton, Renuables, Gwynedd

Publications arising from this experiment

Gwyther CL, Jones DL, Golyshin PN, Edwards-Jones G, McKillen J, McNair I, McDonald J, Williams AP (2013) Bioreduction of sheep carcasses effectively contains and reduces pathogen levels under operational and simulated breakdown conditions. Environmental Science & Technology 47, 5627-5275.

Gwyther CL, Jones DL, Golyshin PN, Edwards-Jones G, Williams AP (2012) Fate of pathogens in a simulated bioreduction system for livestock carcasses. Waste Management 32, 933-938.

Gwyther CL, Williams AP, Golyshin PN, Edwards-Jones G, Jones DL (2011) The environmental and biosecurity characteristics of livestock carcass disposal methods: A review. Waste Management 31, 767-778.

Williams AP, Edwards-Jones G, Jones DL (2009) In-vessel bioreduction provides an effective storage and pre-treatment method for livestock carcasses prior to final disposal. Bioresource Technology 100, 4032-4040.

Photographs of the trial

Figure 1. The field site at Henfaes Research Centre with five Bioreduction vessels, its own metered electricity supply, and biofiltration system.

Figure 2. Close-up of a horizontal Bioreduction vessel

Figure 3. Laboratory-scale Bioreduction experiment to assess the effectiveness of enzyme inoculants