ASABE Technical Library - Abstract

Abstract. Concentrated swine farming operations produce sizeable amounts of manure, which is commonly treated using anaerobic lagoons that have been associated with a number of adverse environmental and health problems. The benefits of anaerobic digestion (AD) of manure – methane capture, renewable energy, and pathogen inactivation — have been well documented; however, an important barrier to adoption of this technology for many swine producers is the high water content of manure from water-wash systems that use lagoon treatment lagoons. The recent introduction of a separation system allows for the collection of manure without added water either as separate scraped solids and liquids or as whole slurry. Experimentally determining the reaction rate of methane production of manure solids will help define new opportunities for this technology and will illustrate the potential of utilizing AD for high manure solids. A biochemical methane potential (BMP) assay of feedstock collected with the scraper system was conducted at mesophilic temperature (35°C) to determine methane production potential. Unexpected results included continuous drop of the methane production readings, and negative volume readings for the control replicates, which indicate a negative pressure inside batch reactors. While the research team was unable to explain observed results, possible explanations include inadequate inoculum sourcing, high operating temperature, and incomplete factors consideration for final gas measures. Existing literature does not offer comparable results to the results obtained during the BMP assay. Future research should focus on understanding the various factors that must be considered when conducting a BMP assay, as no official protocol is available.

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