Submitted to: Water Research
Publication Type: Abstract Only
Publication Acceptance Date: 10/21/2012
Publication Date: 1/16/2013
Citation: Cook, K.L., Loughrin, J.H., Sistani, K.R. 2013. Microbial populations associated with agricultural wastewaters and wastewater treatment. Water Research. Abstract. Interpretive Summary:
Technical Abstract: Over the last 30 years animal production has become increasingly intensive with fewer operations producing larger numbers of animals. As a consequence, the animal waste is produced and maintained in fewer facilities and in greater concentrations. The manure is a valuable resource for crop fertilization and soil conditioning. However, there are also significant concerns associated with the handling of increasing volumes of animal wastes. Microorganisms are central to both the beneficial (nutrient cycling, biogas production) and detrimental (i.e., pathogens , eutrophication of waterways) aspects of animal manures. Therefore, characterization of microbial ecosystems associated with livestock manure and storage systems should aid in developing better means for management and usage of waste materials. We have used a combination of molecular microbiological approaches including quantitative, real-time PCR, cloning and sequence analysis and denaturing gradient gel electrophoresis to describe microbial communities associated with agricultural waste and waste treatment systems. Findings suggest that important functional (e.g. sulfate reducers, denitrifiers and methanogens) and indicator (Clostridium/Eubacterium, enterococci and Bacteroides spp.) bacterial communities in waste treatment systems vary with both environment (season, depth) and treatment system. For example, in swine slurry the concentration and diversity of Bacteroides sp. was found to be seasonal (up to 90% decrease between March and June) while Hespellia sp. and other clostridial species were endemic (concentrations up to 1.0 X 107 cells mL-1 slurry) regardless of time of the year or lagoon depth. The microbial population in swine slurry from an anaerobic digester which was re-circulated through silicone membrane in an external aeration chamber caused changes in biogas (control digesters produced 803 L of biogas and 483 L of CH4 while treated digesters produced 884 L of biogas and 539 L of CH4) which are being explored as a means to improve biogas quantity and quality.