Impact/Purpose:

Regulators and the regulated community who process animal wastes from feedlots

Description:

The purpose of the paper is to present technical guidance to which EPA Region 5 will refer as we work together with those states that intend to allow concentrated animal feeding operations to apply manure to land in the winter. For this purpose, Region 5 assumes that the risk of runoff will be minimized if a state requires injection or timely incorporation of manure in the winter, provided that the CAFO owner or operator adheres to the setback requirements in 40 CFR section 412.4(c)(5). Further, we assume that the risk of runoff will be minimized if surface waters and conduits to surface waters are upslope from land on which manure would be surface applied. Thus, the balance of this guidance is intended to serve as a basis for evaluating, under 40 CFR section 123.36, the adequacy of draft standards that would allow surface application without timely incorporation where surface waters and conduits to surface waters are downslope from the land on which the manure would be applied. When manure is surface applied without timely incorporation, we assume that nutrients and manure pollutants will dissolve or become suspended in water which comes into contact with the manure. This assumption is consistent with the findings reported in the literature. The guidance includes equations that combine the principles of gravity settling and biochemical oxygen demand (BOD) exertion in wastewater engineering with the principles of precipitation runoff in hydrology to predict, in general, the quality of runoff as it enters surface waters or conduits to surface waters. As is shown in the guidance, all the equations include units of time either as a solution or a variable. Thus, the essence of the guidance is to compare for each field the time it takes manure-laden runoff to travel over the land against the degree of treatment that the forces of gravity or the land will provide in that time.

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