Author: Sheridan Kidd Haack, Research Hydrologist/Microbiologist, U.S. Geological Survey
We would be unwilling to state that a specific measure should be used. It is clear that we have had outbreaks of human illness that involve manure-associated pathogens. These usually involve several things.
First, there may be a deficiency in the manure application process (such as applying in excessive amounts, too close to a water body without a buffer of some kind, just before a heavy rain, or on frozen ground) that allows manure to get into drinking or recreational water.
There may also a deficiency (in relation to drinking water) of siting and/or maintenance of wells such as in the case studies mentioned in the Web cast (archived Web presentation by Dr. Haack) (not factors under control of the livestock producer). As we become better educated about pathogens—their numbers, presence, and persistence in the environment, fields, or water, we may find that relying on fecal coliform numbers (indicator organism) is not sufficiently protective, and we may find that we need to implement some types of treatment measures.
Author: Rick Koelsch, Livestock Environmental Engineer, University of Nebraska, rkoelsch1@unl.edu
The U.S. Environmental Protection Agency (EPA) has reviewed the need to establish specific best management practices (BMP) requirements for pathogens in response to a 2nd Circuit Court decision specific to the federal Concentrated Animal Feeding Operation (CAFO) regulations. In their proposed changes to the CAFO regulations in response to this court decision, EPA has determined that it will not add specific BMP expectations targeting pathogens.
It is assumed that EPA recognizes that many of the existing BMP requirements for nutrients are also appropriate for reducing pathogen risk. Currently required practices on CAFOs that target reduced erosion, runoff, and nutrient transport from land application sites are generally the same BMPs that would be recommended for reducing pathogen transport to surface water. In addition, collection and containment of runoff from open lot animal housing is required of all CAFOs to eliminate a primary potential direct pathway for nutrients and pathogens to surface water. These practices are generally required on livestock operations greater than 1,000 beef cattle or a rough equivalent manure production level in other species.
Several treatment technologies can reduce the risk of pathogens prior to land application, none of which are currently required. Compost is a good option for livestock operations with a drier manure product (70% moisture content or less). A number of other technologies have shown promise for reducing pathogen risk for slurries and liquids but have not been widely applied due to economic or technical considerations. Dr. Chip Simmons of North Carolina University summarizes several of these technologies in his archived Web presentation found at http://lpe.unl.edu/archive2.html#dec06 ram.
It is my opinion that the greatest opportunity for reducing pathogen risk is among the unregulated smaller animal feeding operations. While many have implemented BMPs, runoff from open lots and outdoor feeding areas on smaller operations continues to present a concern.
Additional reading:
Manure Composting as a Pathogen Reduction Strategy
