Authors: Chip Simmons, Ph.D., Assistant Research Professor, University of North Carolina at Chapel Hill, School of Public Health, osimmons@email.unc.edu; Mark Rice, Extension Specialist, North Carolina State University, jmrice@eos.ncsu.edu
Pits and other slurry-based systems are not designed as "treatment" systems but are actually intended to conserve nutrients that may then be utilized for crops during the growing season. These systems are anaerobic, much like those anaerobic lagoons used for waste management in warmer climates, so there are similar biological processes occurring within these storages. There should be some minimal amount of natural pathogen removal (settling) or die-off over time, as these storage structures are typically designed to contain the wastes for several months. Time that manure is stored may be as important as the conditions of the holding structure. Some of the common parameters that adversely affect pathogens during storage are ultraviolet (UV) inactivation at the surface of an outdoor holding structure, settling, particle attachment (may aid with settling), natural predation by other microbes, freezing (depending on the class of microbe, this may also have some protective effects), and other natural losses.
