Odour emissions from anaerobic piggery ponds. 2: improving estimates of emission rate through recognition of spatial variability

Odour emission rates were measured for seven different anaerobic ponds treating piggery wastes at six to nine discrete locations across the surface of each pond on each sampling occasion over a thirteen month period. Significant variability in emission rates were observed for each pond. Measurement of a number of water quality variables in pond liquor samples collected at the same time and from the same locations as the odour samples indicated that the composition of the pond liquor was also variable. The results indicated that spatial variability was a real phenomenon and could have a significant impact on odour assessment practices. Considerably more odour samples would be required to characterise pond emissions than currently recommended by most practitioners, or regulatory agencies.

Odour emissions from anaerobic piggery ponds. 1. Results of a three season, 14-month survey

Odour emission rates were measured for seven different anaerobic ponds treating piggery wastes at six to nine discrete locations across the surface of each pond on each sampling occasion over a 14-month period. Emission rate values varied between ponds, between seasons for the same pond and even for the same pond on different days of a sampling week. Average seasonal emission rates ranged from 7.9 to 46.5OU/m(2)s, while average emission rates ranged from 16.0 to 29.0OU/m(2)s. Factors potentially responsible for the variability in emission rates were investigated, including air and pond liquor temperatures, time of day of sample collection, season and the impact of a prolonged drought.

Microbiological status of piggery effluent from 13 piggeries in the south east Queensland region of Australia

AIMS

To assist in the development of safe piggery effluent re-use guidelines by determining the level of selected pathogens and indicator organisms in the effluent ponds of 13 south-east Queensland piggeries.

METHODS AND RESULTS

The numbers of thermotolerant coliforms, Campylobacter jejuni/coli, Erysipelothrix rhusiopathiae, Escherichia coli, Salmonella and rotavirus were determined in 29 samples derived from the 13 piggeries. The study demonstrated that the 13 final effluent ponds contained an average of 1.2 x 10(5) colony-forming units (CFU) 100 ml(-1) of thermotolerant coliforms and 1.03 x 10(5) CFU 100 ml(-1) of E. coli. The Campylobacter level varied from none detectable (two of 13 piggeries) to a maximum of 930 most probable number (MPN) 100 ml(-1) (two of 13 piggeries). Salmonella was detected in the final ponds of only four of the 13 piggeries and then only at a low level (highest level being 51 MPN 100 ml(-1)). No rotavirus and no Erysip. rhusiopathiae were detected. The average log10 reductions across the ponding systems to the final irrigation pond were 1.77 for thermotolerant coliforms, 1.71 for E. coli and 1.04 for Campylobacter.

CONCLUSIONS

This study has provided a baseline knowledge on the levels of indicator organisms and selected pathogens in piggery effluent.

SIGNIFICANCE AND IMPACT OF THE STUDY

The knowledge gained in this study will assist in the development of guidelines to ensure the safe and sustainable re-use of piggery effluent.