An update on litter amendments and ammonia scrubbers for reducing ammonia emissions and phosphorus runoff from poultry litter

Authors: Moore Jr, Philip

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/14/2022
Publication Date: 4/18/2022
Citation: Moore Jr, P.A. 2022. An update on litter amendments and ammonia scrubbers for reducing ammonia emissions and phosphorus runoff from poultry litter. Meeting Abstract. a.

Interpretive Summary:

Technical Abstract: Phosphorus (P) runoff and ammonia (NH3) emissions are two of the biggest environmental problems associated with poultry production. Additions of alum to poultry litter is a best management practice (BMP) that greatly reduces NH3 volatilization from litter, as well as P runoff and leaching. Due to the economic benefits from improved poultry performance alum is currently used to grow 40% of the broilers in the USA. However, in recent years, alum additions to poultry litter have not always resulted in the same reduction in soluble P as in the past. The objectives of this research were: (1) to determine why alum occasionally fails to reduce soluble P in poultry litter, and (2) to determine if aluminum (Al), calcium (Ca), or iron (Fe) nanoparticles when applied alone or in combination with conventional litter treatments for NH3 control, such as alum or sodium bisulfate, would reduce soluble P. The first study conducted utilized poultry litter from a chicken house that had been treated with sodium bisulfate ten times over the past two years. Sodium bisulfate is an acid marketed by Jones-Hamilton as the product PLT (Poultry Litter Treatment) for NH3 control. The results showed that alum additions to PLT-treated litter increased soluble P by 53%, rather than decreasing it. In order to determine if the addition of PLT actually caused this failure a second study was conducted with litter that had never been treated with PLT. When alum was applied alone the soluble P was reduced by 43%, however, when alum was applied in combination with PLT the soluble P increased by 38%, probably due to the formation of sodium alunite [NaAl3(OH)6(SO4)2], a mineral often found in acid soils where sulfate applications have occurred. The formation of this mineral likely inactivates the Al with respect to P adsorption or precipitation reactions. Applications of PLT alone also increased soluble P in litter. Subsequent experiments showed that the Ca- based nanoparticle product TPX produced by N-Clear Inc. was very effective in reducing soluble P in litter, either when applied in combination with alum or PLT. Surprisingly, when TPX was applied with PLT at these very low levels of TPX the SRP levels of PLT-treated litter decreased from 3,410 mg P/kg (PLT alone) to 1,220, 541, and 233 mg P/kg litter, respectively, when 0.25, 0.5, and 1% TPX was added with PLT. These rates of TPX would be equivalent to adding 100, 200, and 400 lbs per 16,000 square ft poultry house with 20,000 broilers. This research indicates that the most important poultry litter treatments used in the USA (alum and PLT) could be significantly improved by the addition of TPX, which would greatly reduce non-point source P pollution from fields fertilized with poultry litter. Another technology used to control NH3 emissions from animal rearing facilities is the use of NH3 scrubbers. These scrubbers, which are widely used in Europe, purify the air as it is exhausted from facilities (i.e. – end of pipe technology) using sulfuric acid to capture NH3. Since the air inside these facilities is not being purified, the only economic benefit to farmers is the capture of nitrogen (N), which can be used as fertilizer. However, N fertilizer is relatively inexpensive and has about the same value as the acid used to scrub the N from the air, hence, scrubbers are only widely used in Europe where emissions are regulated. Obviously, what is needed is an NH3 scrubber for purifying the air inside chicken houses, which would result in the type of production benefits found with litter amendments (i.e. lower NH3 leads to better weight gains, feed conversion, lower susceptibility to disease, lower mortality and reductions in propane use). The biggest hurdle for the development of NH3 scrubbers for poultry houses is the tremendous amount of dust present in the air, which quickly causes clogging of nozzles used for spr