Prediction of feedlot effluent pond odour emission after significant inflow

Heinrich, Nathan (2004) Prediction of feedlot effluent pond odour emission after significant inflow. [USQ Project] (Unpublished)


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Feedlots in Australia have long been associated with odour, and as such, in the early
1990's research was carried out in order to better understand the processes driving the
odour generation. Since that time, many practices have been identified as contributing
to the odour problem, and feedlot management has changed to minimise the odour
emissions. This has resulted in a distinct lack of odour emissions data relating to
'modern' feedlots.
Feedlot pad surfaces represent the largest odour emitting source, however, after a rain-
fall event, the odour emissions from the effluent ponds increase to a point where it may
exceed that of the feedlot pad surface. Despite this, there has been little Australian
research carried out to determine and predict the odour emissions from feedlot ponds
after an inflow event.
This project set out to develop a model to predict the odour emission rate from the
effluent ponds at a feedlot after a significant inflow. Odour samples were collected every
few days for a period of time after an inflow at two commercial feedlots in Southern
Queensland and Northern New South Wales, and assessed to determine the odour
emission rate. The collected data displayed a similar pattern of odour emission to that
measured in the early 1990's, reported by Casey et al (1997). At both feedlots, the
odour emission rate from the primary holding pond rose quickly to a peak (454 and 578
ou/s.m2) within 5 - 8 days, and then declined steadily back to 'normal' levels within
25 - 30 days.
A model was developed to reproduce the pattern of odour emissions from the primary
holding pond at each feedlot. The model is a two-stage empirical algorithm, and is dependent on the inflow ratio, the 24 hour average ambient temperature experienced
during the days of the rainfall event and the number of days since the first day of the
rain event. A parameter named 'Peak Day' defines the two stages of the model, and
is read from a table developed from the measured temperature data. It is known that
the pond condition does impact the odour emission rate (Hobbs et al, 1999); however
the current body of research is not conclusive, and not enough pond condition data
was collected during the course of the project to permit this model to include pond
condition parameters as input.
The model was tested with a number of hypothetical scenarios, and was also validated
using the data collected by Casey et al (1997). The model was shown to be reasonably
robust to moderate changes in parameter values, but failed to accurately reproduce
the odour emission patterns measured in the earlier work. This was attributed to the
different management practices of feedlots between the two data sets, and the simplistic
nature of the model developed.
The limited number of odour emissions data sets and supporting data meant that a
comprehensive model could not be developed.

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Item Type: USQ Project
Refereed: No
Item Status: Live Archive
Depositing User: epEditor USQ
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering
Date Deposited: 11 Oct 2007 00:14
Last Modified: 02 Jul 2013 22:30
Uncontrolled Keywords: feedlots, feedlot pad surfaces, odour emissions
Fields of Research (FoR): 07 Agricultural and Veterinary Sciences > 0702 Animal Production > 070203 Animal Management
09 Engineering > 0999 Other Engineering > 099901 Agricultural Engineering

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