2002 Annual Report
Research
Effective Use of Solid-Liquid Separation and Aeration to Control Swine
Manure Odor
Jun Zhu, Assistant Professor, Southern
Research and Outreach Center, Waseca, MN
Gene Tinker, Extension Educator, Southern Research and Outreach Center,
Waseca, MN
Robert Koehler, Extension Educator, Southwest Research and Outreach Center,
Lamberton, MN
Funding Source
Minnesota Legislature Rapid Agricultural Response Fund
Objective
The objectives of the project include 1) evaluate the feasibility and
effectiveness of combining solid-liquid separation and aeration to treat
liquid pig manure for odor control, 2) determine the optimal combination
of these two techniques based on solids level in the manure vs. aeration
time, and 3) determine the economics of the treatment system based on
full-scale experiments at farm level.
Project Description
Liquid manure from finishing pigs was categorized into four solids levels,
i.e., 0.5%, 1.0%, 2.0%, and 4.0% by diluting the freshly collected feces
using tap water. The prepared liquid manure were stored in PVC columns
and treated by three aeration times, i.e., 5, 15, and 30 days. Liquid
samples were collected based on protocols and analyzed for biochemical
oxygen demand (BOD), volatile fatty acids (VFAs), total solids (TS), total
suspended solids (TSS), total volatile solids (TVS), total volatile suspended
solids (TVSS), total Kjeldahl nitrogen (TKN), and pH. Air samples were
also collected from the headspace of some columns for olfactometry analysis
to examine possible odor reduction caused by the treatment.
Results
A third of the project has been completed to date. Data obtained thus far shows that the original solids content in manure has a profound influence on the odor generation potential during the anaerobic storage period after aeration treatment. In this study, air samples were collected from those columns aerated for 15 days and the results indicated that the odor threshold for manure with solids content of 4% was the highest in the 90-day storage period after aeration treatment. Unsurprisingly, the manure having solids content of 0.5% had the lowest odor threshold in the same storage period. The odor threshold values for manure with 1% and 2% solids content didn’t differ much from each other, and were located between the highest and lowest values. Although data are limited, the effect of solids level in the manure on odor generation is clearly seen. With more data from the analysis of air and liquid samples underway, a good understanding will be obtained of the relationship between manure solids content and the potential for odor production during storage after aeration treatment.