Department of
Environmental Quality

A permit by rule (PBR) is a process by which a facility that emits air pollutant(s) may register with DEQ in lieu of obtaining a site-specific air quality operating permit. A PBR is a simple and efficient alternative to an individual permit. In a PBR, requirements are spelled out in the rule and apply to all members of a particular industry.

In April 2005, in response to a request by the Independent Dairy Environmental Action League (IDEAL) and the Idaho Conservation League (ICL), a negotiated rulemaking was initiated to consider air quality permit rules to control ammonia from dairy farms. Participants in the negotiated rulemaking included representatives of the Idaho Dairymen's Association, Milk Producers of Idaho, ICL, Idaho State Department of Agriculture (ISDA), and DEQ. The negotiated rulemaking culminated in development of a PBR for dairy farms. The rule was approved by the Idaho Board of Environmental Quality in February 2006 and took effect July 1, 2006.

It requires dairy farms above specified threshold numbers of cows or animal units to register with DEQ and to implement industry best management practices (BMPs) to control ammonia emissions. A list of BMPs is contained in the rule. Each BMP is assigned a point value. Dairy farms must employ BMPs totaling 27 points.

Why control ammonia emissions?

Ammonia is a common by-product of animal waste. The volume of ammonia emissions depends on manure characteristics and how the manure is managed.

Ammonia emissions are an environmental concern because they can adversely impact water and air quality. Ammonia emissions can contribute to eutrophication of surface waters and nitrate contamination of ground water. In addition, when emitted ammonia is combined with acidic compounds in the upper atmosphere, fine dust particles (particulates) capable of being inhaled are formed. These particulates have been related to atmospheric haze, and also have been attributed to a variety of adverse human health effects, including premature mortality, chronic bronchitis, asthma, and other respiratory ailments.

Who does the PBR apply to?

The PBR applies to dairy farms with a capacity to produce 100 or more tons of ammonia emissions per year. (Dairy farms with fewer than the specified number of animal units or mature cows may opt into the PBR program as well.) The capacity to produce is based on the number of animal units or mature cows and the type of manure collection system. The tables below shows the applicable thresholds prescribed in the rule:

1  Assumes expected level of N->NH3 volatilization for drop-hose or ground level liquid manure application.

2  Assumes expected level of N->NH3 volatilization for center pivot or other conventional sprinkler irrigation liquid manure application

What types of BMPs can dairies employ?

The rules prescribe various BMPs to control ammonia emissions, ranging from installing certain types of waste storage and treatment systems to implementing composting practices to exporting manure. A point value is assigned to each BMP. Dairy farms must employ BMPs totaling 27 points.

• List of Ammonia Control Practices (IDAPA 58.01.01)

The use of Zeolite applications has been added to the list of Ammonia Control Practices. Refer to the following for supporting documentation:

• Zeolite - Request for Addition to Rule
• Effect of Adding Alum or Zeolite to Dairy Slurry on Ammonia Volatilization and   Chemical Composition
• Peat Zeolite Basalt as Adsorbents of Ammoniacal Nitrogen During Manure   Decomposition
• Performance of Natural Zeolite as a Feed Additive in Reducing Aerial Ammonia   and Slurry Ammonium Ion Concentration in the Pig Farm Nursery

How do dairy farms comply with the PBR?

To comply with the PBR, dairy farms subject to the rule must register with DEQ and ISDA by providing the following information:

• name, address, location of dairy farm, and telephone number
• information on the size and type of the dairy farm
• information on the type of BMPs that the dairy farm is employing to total 27 points

• Permit by Rule Registration Form

How will the state ensure compliance?

Within 30 days of receiving a dairy farm's registration information, ISDA will conduct an inspection to ensure that the required number of BMPs are employed. ISDA will also provide compliance assistance if needed. If ISDA finds that BMPs are lacking, it may issue a warning letter.

• ISDA's 2008 Ammonia Emissions Program Update
• DEQ's Response to ISDA's 2008 Ammonia Emissions Program Update

Enforcement of the rule is DEQ's responsibility. Enforcement methods include filing a notice of violation or refering the case to the Attorney General's office for civil enforcement. In the event of unforseen equipment upsets and breakdowns, DEQ will exercise enforcement discretion. So long as corrective action is taken within a reasonable time, which would depend on specific circumstances, the event will not reduce the BMP point value. In the event of an emergency, the farm could apply for and be granted an exemption for up to one year.