Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/3/2006
Publication Date: N/A
Technical Abstract: Background and Aims: Modern high intensity dairy farms generate large amounts of waste (manure and urine) that is stored in lagoons until it is disposed of by land application on crop fields. This practice has resulted in nutrients leaching into ground and surface waters, poor air quality from volatile compound emissions, and the contamination of crops with pathogenic bacteria. Pretreatment of waste by aerobic or anaerobic digestion before storage and subsequent land application may alleviate these problems; however, little is known about the effect these treatments have on the bacterial propulation structure of waste. Methods: Lab-scale aerobic and anaerobic digesters were continually fed fresh dairy waste and their effluent stored in simulated waste lagoons for 6 months. Samples were taken from the waste material, the aerobic and anaerobic digester effluents, and the simulated lagoons at regular intervals. 16S rDNA sequence libraries were constructed from these samples and the types of bacteria present were determined. Results: The bacterial population structure of dairy waste was altered the greatest by aerobic digestion with significant differences in 8 out of 9 phyla identified, while those from the anaerobic digester showed significant differences in 5 of 9 phyla. Untreated waste that was only held in simulated waste lagoons revealed little change with only the phylum. Spirochetes showing a slight but significant increase. Conclusion: Aerobic and anaerobic digestion of dairy waste alters the bacterial population structure and chemical composition of dairy waste, producing stable populations with unique characteristics.