Improvements in Environmental Quality and Animal Productivity with Advanced Manure Treatment

Abstract

To be permitted, new swine waste management systems in North Carolina need to meet the strict performance standards of an environmentally superior technology (EST). These technologies must be able to substantially remove nutrients, heavy metals, emissions of ammonia, odors, and pathogens. Our objective was to demonstrate, at full-scale, a second generation treatment system for swine waste that can achieve the high treatment performance standards of an EST, yet it is four times more economical than earlier versions. The system combines solid-liquid separation, biological ammonia treatment, and phosphorus removal and produces a deodorized and disinfected liquid effluent. The second generation system was installed full-scale in a 5,150-head finishing swine operation and demonstrated under steady-state conditions and cold and warm weather. The system removed 98% of the suspended solids, 100% of biological oxygen demand, 97% of the ammonia, 94% of the phosphorus, 99% of the copper and zinc, 99.9% of the odor compounds, and reduced pathogens 4-logs (99.99%). Ammonia concentration in the air of the barns was significantly reduced, and animal health and productivity were enhanced. Compared to the traditional lagoon management, the animal mortality decreased 57%, the rate of daily weight gain increased 11%, and the rate of feed conversion into meat improved 5.4% with the new manure management system. These findings showed that two or more simple processes can be combined into a practical system to achieve the strict EST performance standards and that these cleaner technologies can have significantly positive impacts on animal productivity and the environment.