EMC Adopts Temporary Animal Odor Control Rules
RALEIGH -- North Carolina soon will begin enforcing one of the nation’s first comprehensive programs for controlling odors from livestock operations, under new rules that the state Environmental Management Commission (EMC) adopted today.
The rules establish required management practices that all animal operations must follow, if they meet certain size thresholds and use lagoons and sprayfields to dispose their wastes. Hog farms account for most of the facilities that must comply with the new rules, but some dairy and poultry farms also will be affected.
The rules, which take effect March 1, are considered temporary measures. Before adopting permanent rules, the EMC plans to hold a series of public hearings this summer across the state to gather public input.
“Hopefully, these rules will help reduce some of the odors from hog farms and other livestock operations,” said Bill Holman, assistant secretary for the N.C. Department of Environment and Natural Resources (DENR), which will enforce the rules. “Ultimately, however, the solution is to convert farm lagoon and sprayfield operations to waste treatment systems that do not produce objectionable odors.”
The odor-control rules apply only to animal operations using liquid waste-treatment systems, such as lagoons and sprayfields. Regulated facilities also must contain at least 250 hogs, 100 cattle, 75 horses, 1,000 sheep, or 30,000 chickens or turkeys. The rules will not apply to smaller facilities or those with dry litter operations, which include most poultry farms.
The odor rules are aimed at reducing objectionable odors beyond the boundaries of animal operations, phased-in by increasing levels of control. As a first step, all animal operations that meet the size thresholds and use liquid waste-treatment systems must comply with a list of required management practices for controlling odors. For example, farm operators are not allowed to use sprayfields when winds could cause wastewater to drift offsite, except during emergencies when waste lagoons are in danger of spilling.
As a second level of control, DENR will require farms to prepare detailed best management plans for controlling odors at all new or modified animal operations and existing facilities that cause objectionable odors. These best management plans will contain a list of low-cost actions for reducing odors. If objectionable odors persist, facilities will have to submit modified plans and eventually could be required to install odor-control equipment, such as lagoon covers or “wash walls” that filter odors from barn ventilation systems.
DENR inspectors will determine whether animal operations have objectionable odors based on a combination of factors, include personal observations, complaints from nearby residents, and health studies. Other factors to be considered include the nature, intensity, frequency, pervasiveness and duration of odors.
The 1997 session of the General Assembly directed the EMC to develop temporary rules for controlling odors from animal operations by March 1, 1999, “if economically feasible odor control technology for animal operations is available.” The legislature instructed the commission to base these rules on a University of North Carolina system study on the technologies available for controlling odors from animal operations, including hogs, poultry and other livestock.
The legislature called for the odor controls in response to increasing complaints about animal operations, largely due to the expansion of the hog industry in Eastern North Carolina. The number of hogs in the state has increased by four-fold since 1990, mostly in the Coastal Plain. Odor problems also can be associated with other kinds of animal operations that are widespread in the state, including chickens, turkeys, and cattle.
Most objectionable livestock odors are caused by animal wastes and waste-disposal systems, but problems can be aggravated by improper handling of dust, feed storage areas, and dead animals. Weather conditions also contribute to problems, with odors more prevalent when it is not raining and the air is still -- such as during the evening and early morning hours. Other factors that can contribute to odors include the size of the facility; type of animals; proximity to residential areas; and management practices at a facility.
Reliable methods for measuring odors precisely are not available currently. Objectionable odors may be caused by thousands of different compounds, some of which can be smelled at extremely low concentrations that cannot be measured with available instruments. In addition, people vary widely in their sensitivity and reactions to odors. Smells that bother one person might be acceptable or even pleasant to another.
These factors led the Environmental Management Commission to conclude that the best initial strategy for controlling odors is to require and promote livestock practices that reduce or prevent odor problems. North Carolina is among the first states to develop comprehensive rules for controlling odors from animal operations.
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Tom Mather, (919) 715-7408
Date released: 02/11/99
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