# Presentation: 138334

## Air Quality Issues Related to Manure Management in Oregon2008 Animal Waste Management WorkshopAlbany, ORFebruary 13, 2008

- United States Department of AgricultureNatural Resources Conservation Service

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## What Are Nutrients?

- Chemical elements/compounds
- Have value as an input to biological systems
- This value can be either positive or negative
- If all nutrients are utilized, there is no potential for loss

## More on Nutrients

- The reality is that living systems are not perfect
- Nutrients are not always applied according to proper:
- Location
- Timing
- Rate
- Methodology

## Playing by the Rules

- Law of Conservation of Mass
- Matter cannot be created nor destroyed
- But, it can change form
- Each element (carbon, nitrogen, oxygen, etc.) does not just disappear or go away

## Where Can Nutrients Go?

- To the plant
- Stay in the soil
- Leach into the water system
- Volatilize into the air
- Fixing a water problem, usually leads to a soil, air, etc., problem

## What Are the Nutrients that Affect Air Quality?

- Manure management for water quality is typically focused on N, P, and K
- P and K are not usually volatilized
- The main air quality emissions from manure management arise from C, N, and S

## NRCS and Air Resources

- 12 of 79 current NRCS resource concerns are related to air quality and atmospheric change (AQAC)
- Effort to consolidate to one main AQAC resource concern with various components

## Proposed AQAC Resource Concern Components

- Particulate Matter
- Ozone Precursors
- Greenhouse Gases
- Odors

## Foundation Agricultural Air Emissions

- Direct PM emissions  (PM)
- Ammonia  (PM, Odors)
- VOCs (O3, Odors, PM)
- Odorous sulfur compounds  (Odors)
- NOx  (O3, PM)
- CO2  (GHGs)
- N2O  (GHGs)
- CH4  (GHGs)

## Carbon-Based Air Emissions

- Manure and other biological matter contain long-chain carbon compounds
- Long-chain carbon compounds are broken down through decomposition to shorter-chain carbon compounds
- Shorter-chain carbon compounds are broken down eventually to CO2 or CH4 or released as volatile organic compounds (VOCs)

## Slide 11

## Nitrogen-Based Air Emissions

- Nitrogen in organic matter (proteins, amino acids, urea) generally converts to ammonium-N (NH4+ or NH3)
- Ammonium-N can be converted through a variety of nitrogen oxidation and reduction reactions
- Nitrogen can be volatilized as NH3, N2O, NOx, or N2

## Slide 13

## Other Manure-Based Air Emissions

- Sulfur in feed, water, and manure can undergo conversion to odorous sulfur compounds
- H2S
- Mercaptans
- Dimethyl Disulfide, etc.
- Solid manure particles and animal dander can be emitted as particulate matter
- Liquid and gaseous pollutants can react or condense to form particulate matter

## Slide 15

## Location, Location, Location

- Dealing with air quality is a function of location
- If you are in an area with bad air quality, you will have more requirements
- If you are near a Federally-protected airshed, you will have more requirements
- If you are in an area that has an urban/rural interface, you will likely have more pressure

## Oregon Air Quality

- It’s pretty good (right now)
- Only 3 counties don’t meet federal air quality standards
- EPA has changed/will change several standards that may impact other counties
- There are 11 federally-protected airsheds

**Notes:**
Lane Co. (top 25% of U.S. ag production) is NA for PM10

## Managing Manure for Air Quality

- Use a nutrient management approach
- Inputs will affect outputs
- Be efficient
- Understand the variables in air emissions formation

## Nutrient Management Approach

- Overall goal (of a CMNP) is to incorporate practices for utilizing animal manure and organic by-products as a beneficial resource while minimizing negative effects on resources
- Air is one of those resources
- If the nutrients in the manure are not available for utilization, we haven’t accomplished the goal

## Managing Manure Inputs

- Elements/compounds in the animal production inputs will impact what is in the animal outputs
- Feed
- Water
- Additives
- Feed management is an important tool

## Be Efficient

- Efficiency (or lack thereof) has a big influence on air emissions
- If nutrients are efficiently utilized for agricultural production, there is less left to be emitted
- Utilization in the animal, as well as utilization of manure

## Air Emissions Formation

- Recall the C and N diagrams
- Think in terms of the type of manure management system
- Solid vs. liquid/slurry
- Aerobic vs. anaerobic

## Solid Systems

- Typically aerobic
- May have anaerobic pockets, if moisture content is too high
- Carbon volatilizes mainly to CO2 or stays solid
- Some VOCs and CH4
- Some carbon PM

## Solid Systems (cont.)

- Nitrogen volatilizes mainly to N2 or stays as NO3-
- Can have high NH3
- Can have high N2O
- Can have some NOx
- Sulfur will typically not volatilize
- Some odorous sulfur formation in anaerobic pockets

## Liquid/Slurry Systems

- Can be aerobic or anaerobic
- Aerobic liquid/slurry systems usually require large energy input
- Carbon volatilizes mainly to CO2 (aerobic) or CH4 (anaerobic) or stays solid
- Some VOCs

## Liquid/Slurry Systems (cont.)

- Nitrogen volatilizes mainly to N2 or stays as NO3-
- Can have some NH3, but high moisture content keeps much of it in solution
- Can have some N2O
- Can have some NOx
- Sulfur will volatilize to odorous sulfur compounds in anaerobic systems or in anaerobic pockets

## Emissions Generation and Release Parameters

- Nutrient/carbonaceous matter content
- Nutrient/carbonaceous matter bioavailability
- Oxygen availability
- Moisture content
- Temperature
- pH
- Time
- Compound reactivity
- Gas concentrations

## Summary

- Nutrients have to go somewhere, and there are limited options
- Air emissions are closely tied to specific elements/compounds
- Managing manure for air quality is similar to the process for water quality
- Look for the “weak links” in the emissions formation and release chains

## Questions?

- Greg Zwicke
- greg.zwicke@por.usda.gov
- (503) 273-2434
- www.airquality.nrcs.usda.gov