For this study, composite samples of raw/mixed/uncomposted manure from the Experiment Station feedlot at Bushland have been sent for testing at several labs. The manure samples were harvested May 17-June 2 from two types of pens.
One set of pens were paved with fly-ash, a byproduct of the coal-fired power generating industry, and the other manure was from unpaved pens. The manure was composted and test results from the two showed a large difference for several constituents measured, especially ash content, Sweeten said.
Ash, an unusable material as far as energy is concerned, was lower in the composted manure samples from the paved pens than the dirt pens ?20.2 percent compared to 58.7 percent. As a result, the low-ash manure had about twice the organic matter and heating value, he said.
"The low-ash feedlot biomass would be much better fuel than high-ash feedlot biomass," Sweeten said. "The problem is, there is not that much of it in the commercial feedlots."
Large bulk samples from the compost pile that came from the paved pens will be tested further in a small-scale combustion testing project in College Station.
These test results will focus on using pulverized manure samples as reburn fuel in a secondary combustion chamber to lower the nitrogen oxides and specific metal emissions from coal-firing in the primary combustion chamber, Sweeten said.
Re-sampling will begin next week upon completion of 50 days of composting of the two windrows. The analysis will be repeated on the partially-composted manure to determine changes in fuel quality produced by more than six weeks of composting, he said.
Another research project involves using the byproduct combustion ash as a fertilizer or construction material, Sweeten said.
"By assuring year-round uses of manure, the cattle feed yards in this area could not only stay current on manure harvesting, but the fuel quality
Source:Texas A&M University - Agricultural Communications