Particulate matter adjacent to cattle deep-bedded

monoslope facilities

Mindy J. SpiehsApril 4, 2013

Waste to WorthDenver, CO

Project Overview• Project is part of USDA AFRI Air Quality Grant

– South Dakota State University– Iowa State University– Livestock Poultry and Environmental Learning

Center– USDA ARS

• Meat Animal Research Center, Clay Center, NE• Cotton Production and Processing Research Unit,

Lubbock, TX

Bedding and manure management• Producers manage

bedding/manure two ways:– Allow a bedded pack to

accumulate in center or pen

– Scrape and haul all bedding and manure weekly

• Manure may be stored under roof in manure bay or in outdoor pile until land applied

• Fresh bedding added to pack 1 – 2 times per week

Purpose of Air Quality Grant• Gather baseline emission data from beef

confinement barns

• Evaluate 2 manure handling systems

Weekly Scrape and HaulSouth Dakota Sites

BedpackIowa Sites

Monitoring Weather

• On-site weather station measured– Wind direction– Wind speed– Ambient air

temperature– Relative humidity

Monitoring the Barns• Two barns in South Dakota and

two barns in Iowa were monitored

– Two mobile instrument trailers were rotated between the barns

– Continuous gas measurements were taken from each barn for one month each season for two years

• Two air inlets on the south side of the barn and six air inlets on the north side of the barn continuously collected air samples to analyze for

– Ammonia– Hydrogen sulfide– Methane– Carbon dioxide– Nitrous oxide

• Particulate matter was monitored periodically

Monitoring Particulate Matter• South Dakota Sites

– Measured using Minivols– Collected baseline

emission data

• Iowa Site – Measured using Lo-Vol

Particulate Air Samplers

– Collected baseline emission data

– Evaluated particulate matter concentration relative to management events

Objective• Compare particulate matter concentration

adjacent to a deep-bedded monoslope facility during normal operation and a bedding event.

Sampling procedure• Lo-Vol Particulate

Samplers – Three placed 4.6 m (15 ft)

from the north side of the building

– Three placed 4.6 m (15 ft) from the south side of the building

– 36.6 m (120 ft) between the samplers on each side

• Average sampler flow rate was 16.7 L/min.

Sampling procedure• Each sampler contained pre-weighed filters

• At the end of the sampling period, filters were collected and sent to USDA ARS Cotton Production and Processing Research Unit, Lubbock, TX to determine total suspended particles (TSP).

• Samples were collected over two five-day periods– April 28 – May 5, 2011– June 24 – July 1, 2011

• Each sample period included three 24-hr collections during normal operation and two 3-hr collections during a bedding event

Statistical Analysis• Data were analyzed using SAS PROC MIXED to

determine differences between sampling events (Bedding vs. Normal Operation) and sampling periods (April – May vs. June – July)

• No event by sampling period interaction was detected (P = 0.1794)

• No significant difference between sampling periods was detected (P = 0.1807)

Results

Bedding EventPrevailing South wind

Bedding EventPrevailing North wind

Bedding EventSlight south wind

Bedding EventWind changed direction during

sampling

Average Concentrations• Average 24-hr TSP concentration on days of

normal operation was 58.6 ± 3.9 µg/m3

• Average 3-hr particulate matter concentration during a bedding event was 702.2 ± 266.1 µg/m3

• TSP significantly higher during bedding events compared to normal operations (P = 0.0040)

Conclusions• In general, particulate matter concentrations

adjacent to the deep-bedded monoslope facility were lower than previously reported for open lot feedlots.

• Concentrations of TSP were higher during the 3-hr bedding event than during normal operation but quickly return to baseline levels following bedding event.

Thank You!