Feedlot waste management project

Summary

General

1. So that industry expands in harmony with public expectations and so that guidelines and by-laws for the establishment and operation of feedlots can be better formulated, research into feedlot waste management should continue. This would result in a smoother licensing and regulation process.

2. There should be continued community input into feedlot waste management research so that a standard of operation acceptable to the community can be met.

3. QDPI should continue to consult with local authorities, industry and regulatory authorities so all parties can agree on the revised feedlot guidelines.

4. To aid consultants and designers in making the best design decisions for a given case, there is a need to develop large integrated computer models incorporating sub-models of each of the major processes within the overall feedlot waste management system.

5. Research should be undertaken into the value adding of feedlot wastes to obtain the best economic return from its byproducts and facilitate export of excess nutrients from the generating property.

6. An acceptable Australian standard for odour sampling and measurement techniques needs to be finalised. This standard should include forced choice dynamic dilution olfactometry and the standardisation of the result to a panel with a butanol detection threshold of 50 ppb.

7. Research needs to be undertaken into the development of an objective design standard for odour concentrations at receptors. This research will need to be jointly sponsored by the Commonwealth and State Environment Protection agencies. Current odour design objectives have little relevance in the real world and have not recognised the changes in odour measurement technology and the changing nature of the odour standard. There is a clear difference between the odour concentration number which is predicted by a modelling approach and the odour concentration number which would be determined for a receptor. Currently these two numbers are assumed to be the same in regulation.

8. The Australian inter-laboratory olfactometer testing program should continue so that the performance of all Australian olfactometers can be assessed and compared.

9. Further work on enhancing the feedlot emission model is required. Tray (simulated pad) experiments should be undertaken in a controlled environment to isolate the effect of the different factors that impact on odour generation from the feedlot pad. This will require the construction of a controlled environment, recirculating wind tunnel facility.

10. Research should be undertaken to confirm the assumption of the conservative nature of odours in dispersion modelling.

11. Research should be undertaken to define the additive properties of odours where odours from two or more dissimilar sources are being modelled.

12. The effect of background odour levels on emission rate requires further research. This is of particular significance for large feedlot developments.

13. Verification of the use of Gaussian models for large area ground level sources is needed. Feedlots, manure spreading, sewage treatment plants and land fills are virtually the only examples of large areal odour emitting sources.

14. Odour modelling efforts for new or expanded large feedlots are likely to require the collection of long term site specific wind speed and direction data. Historical records of wind direction and wind speed are only available for a limited number of sites in Australia. Very few of these sites are located in rural Australia. The record available from the weather stations currently operated by a number of larger feedlots is often not of sufficient quality to be used for modelling or research purposes. The siting and maintenance of these weather stations on feedlots does not meet the required standards. The development of a procedure for use at sites where this information is not available is required.

15. Further odour impact surveys to refine the methodology and improve knowledge of the odour intensity that is objectionable to the general populace should be carried out at feedlot sites where population density and distribution, terrain, and density of meteorologic data recording stations are suitable

16. The feedlot hydrology model developed during this project should be integrated with the feedlot odour emission model also developed during this project. This would allow the investigation of the effects of feedlot management and design options on the level and duration of odour emission from the pen area.

17. Research is needed into the best design and management practices for retention facilities at feedlots. This research should include the role of bacterial and enzymatic products in assisting the lot feeder to minimise odour generation from these facilities.

18. The type and mass of gaseous and volatile products generated on the feedlot pad is controlled in part by the bacterial population present. The potential for changing the dominant bacterial species present from those that produce highly odourous compounds to those producing less odourous products should be investigated. By selecting/genetically engineering a better behaved bacterial population over those naturally present, it may be possible to establish a bacterial population that out-competes the native population, produces faster breakdown of organic matter with less odour generation. Hydrology

19. The project has defined the hydrologic performance of feedlots to the extent that is required for design and operation at this point in time. The feedlot hydrology model produced is able to accurately represent the hydrology of a conventional feedlot for design and investigation purposes.

20. Relevant state departments and national committees should utilise the findings and outcomes of this research project in the formulation of design recommendations and guidelines for operation of feedlots within their state constraints (climate, social, economic) and bearing in mind the National Guidelines.