Traditionally, swine production and crop production were tightly integrated. Swine were raised on crop residues, and their manure was a valuable fertilizer. Over the past 40 years, however, both crop producers and swine producers have moved away from this integration in an effort to reduce production costs. Crop producers prefer ‘pure’ fertilizers that are easy and accurate to spread, while swine producers prefer to hold animals in large groups in close proximity to feed mills and slaughter plants. Feed ingredients are often imported from distant regions making it financially prohibitive to return the highly dilute manure to the crop-growing areas. Thus, manure ends up being used locally, sometimes at application rates that exceed crop requirements.

This type of swine production has raised environmental concerns and some environmentalists push for a reintegration of crop and swine production through a return to much smaller, diversified family farms. Although components of the RE-Cycle system can facilitate such a movement, the RE-Cycle system is really meant as a solution for the environmental concerns of very large, integrated swine facilities.

The RE-Cycle system is designed to convert waste into value added products (Figure 1). Fecal material is converted into energy and ash. The energy can be captured in the form of electricity or a liquid fuel such as diesel or ethanol. The sterile ash has been successfully used as a mineral supplement in swine feed, eliminating phosphorus as an environmental concern. Nitrogen is recovered and processed into commercial grade nitrogen fertilizer, eliminating nitrogen as an environmental concern.