Using broiler and swine manure lagoon effluent in sawdust-based swine mortality composts: effects of nutrients, bacteria, and gaseous emissions

Authors: McLaughlin, Michael; Brooks, John; Adeli, Ardeshir; Miles, Dana

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/26/2015
Publication Date: 6/1/2015
Publication URL: http://handle.nal.usda.gov/10113/60978
Citation: McLaughlin, M.R., Brooks, J.P., Adeli, A., Miles, D.M. 2015. Using broiler and swine manure lagoon effluent in sawdust-based swine mortality composts: Effects of nutrients, bacteria, and gaseous emissions. Science of the Total Environment. 532:265-280.

Interpretive Summary: Results from repeated experiments using small outdoor experimental bins to test effects of broiler litter and swine lagoon effluent in swine mortality composts varied with seasonal temperatures. Mixing litter 1:1 with the farm standard sawdust bulking agent increased composting temperatures initially and after aeration events; increased levels of all nutrients, except C, in start mixes; increased all nutrients, except C and N, in finish mixes; increased levels of Gram+, Salmonella, and E. coli bacteria in start mixes, but only G+ bacteria were higher in finish mixes; and increased emissions of ammonia and greenhouse gases. Mixing swine lagoon effluent instead of water in starting compost mixes: increased composting temperatures during the early stages of composting; had no effect on nutrient levels; had no effect on Gram+, Gram-, Salmonella, Listeria, or E. coli bacteria; increased Clostridium perfringens counts in start, but not in finish mixes; and had no effect on ammonia and greenhouse gas emissions. Levels of primary fertilizer nutrients in finish composts did not differ for N (average 3.3%), but composts from litter mixes contained more P and K than composts without litter. Increased P in composts changed N:P ratios, which impact decisions on uses of composts as crop fertilizers and soil amendments in nutrient management plans.

Technical Abstract: Disposition of mortalities challenges confined animal feeding operations (CAFOs) especially sow (farrowing) farms, which experience mortalities daily. Environmental regulations and high transportation costs may preclude incineration, landfill burial, and rendering; therefore, swine CAFOs in Mississippi in the Mid-South US often compost mortalities. In the present study, the farm-standard composting mix of sawdust (S) and water (W) was compared with others where additional N was supplied by broiler litter (L) and water was replaced with swine lagoon effluent (E). The objective was to assess effects of these manure byproducts: 1) on nutrients and bacteria in composts destined for land application, and; 2) on emissions of NH3 and greenhouse gases (GHG). Three replications of four mixes (SW, SLW, SE, SLE) were compared in microcosms comprising modified plastic recycling bins. The experiment was repeated three times in different seasons in one year. Mixes were compared for differences in temperature, water content, nutrients (C, N, P, K, Ca, Mg, Na, Mn, Fe, Cu, Zn), bacteria (Gram-, Gram+, Clostridium perfringens, Salmonella, Listeria, E. coli), and emissions (NH3, CO2, CH4, N2O). Litter increased composting temperatures initially and after aerations; increased nutrients, except C, in start mixes and all except C and N, in finish mixes; increased Gram+ bacteria, Salmonella, and E. coli in start mixes, but only Gram+s in finish mixes; and increased emissions. Effluent increased early composting temperatures; had no effect on nutrients; had no effect on bacteria, except increased C. perfringens in start, but not finish mixes; and had no effect on emissions. Primary fertilizer nutrients in finish composts did not differ among mixes for N (average 3.3%), but litter composts had more P and K, and lower N:P ratios.