Date Full Report Received10/02/2016
Date Abstract Report Received10/02/2016
Funded ByNational Pork Board
Pork production is one of the most important agricultural activities in the United States, and 75% of the swine operations are geographically located in the Upper-Midwest. The environmental effects of swine manure storage systems and land application are raising significant concerns, for instance, the threats to surface water and groundwater quality by phosphorus overloading. Meanwhile, swine manure contains a significant portion of small particles with poor settling capability, challenging the solid/liquid separation process via either sedimentation, filtration, or drum screen. Land application of manure is based on crops’ nitrogen requirement, which overloads phosphorus on cropland over the years because of the unbalance nutrient composition in swine manure. A cost effective relocation of excess phosphorus would allow existing animal feeding operations to successfully implement phosphorus-based nutrient management plans on their current land base, increase the valorization of the so-called swine manure waste stream, decrease the environmental impacts from swine operations and increase the national food and resources security. The electrocoagulation process developed in this project effectively assisted natural sedimentation as a separation method. After electrocoagulation and sedimentation, between 70% and 90% of phosphorus can be concentrated in sludge with a volume of only 5% to 10% of the untreated manure volume. The resulting supernatant is more nitrogen concentrated with a nitrogen:phosphorus ratio between 10 and 40, compared with initial ratio of around 2. The sludge has a phosphorus contents of between 5% and 10%. This nutrient composition change provides an opportunity of producing more nutrient balanced manure as fertilizer with less contaminating tendency and of economical long-distance transportation. Based on our pilot scale demonstration results, the techno-economic analysis revealed the capital and operational costs and we also used the present value and annualized cost to show the financial outcomes of installation of the EC into current pig operations. For instance, in a typical barn with 2400-head of pigs, installing and operating an EC in deep-pit manure management system will add $1.03 per grown-finish pig.