Reprinted, with permission, from the proceedings of: Mitigating Air Emissions From Animal Feeding Operations Conference.
This Technology is Applicable To:
The effectiveness of aluminum sulfate (alum, Al2(SO4)3) as a litter amendment in poultry houses has been recognized in several studies. Emission rates of ammonia (NH3) were measured at two 169,000-hen high-rise layer barns in Ohio, for six months. The tests were conducted to evaluate baseline and mitigated emission rates. An alum and aluminum chloride (AlCl3) spraying system was installed in the treated Barn 2. Concentrations of NH3 were measured at the barn exhaust fans and in incoming air, using real-time NH3 analyzers. Temperatures, relative humidity, barn static pressure, and fan operation were also measured.
The average daily mean untreated net NH3 emission rate was 480 g/d-AU (1.35 g/d-hen), where AU is an animal unit or 500 kg (1100 lb) of bird weight. The alum and AlCl3 applications reduced NH3 emission by 23% based on the overall cross-barn comparison of paired emission differences between barns. The NH3 mitigation efficiency of the Al2(SO4)3 application was compromised by clogged nozzles, manure turning, and introduction of a new flock of hens. Higher reductions of 33, 23 and 40% were achieved during later test periods. The application of AlCl3 in the last test was expected to further reduce NH3 emission, but the reduction was only 27%. The lower NH3 emission reduction efficiency of AlCl3 was probably due to higher moisture content of manure in Barn 2.
Applicability and Mitigating Mechanism
- Aluminum sulfate and aluminum chloride can lower manure pH and reduce ammonia emission
- A 3000-gal tank stored the chemicals, and spray tubes and sprinkling nozzles were installed along the barn length
- Solutions were automatically sprayed every hour, for a total of 24 times per day
- The nozzles were easily clogged when spraying aluminum sulfate
- The additional chemical solution increased manure moisture content, especially in cold weather, thus reducing its effectiveness
- The spraying system requires training to operate and maintain
- The chemicals were acidic and corrosive
- Manure on second floor was untreated.
The costs of the alum and AlCl3 were $0.13/L and $0.14/L, respectively, without delivery charges. At each delivery, 5678 L (1500 gal) of alum or AlCl3 was first added into the holding tank, and an equal volume of water was added to produce a 50% solution. The field records showed that five deliveries worth $3700 of alum were used in 85 days, or $44 per barn per day. The automatic spray controller cost about $3000, and the doubled-wall holding tank was $6500. A single wall tank would be less expensive. The labor to maintain the controller, air and water pumps is estimated at 3 hours per week per barn. The air pump provided the pressure for spraying, and the water pump filled the spray pipe with the solution.
Teng Teeh Lim1, Chaoyuan Wang2, Ji-Qin Ni1, Albert J. Heber1, and Lingying Zhao31Purdue University, 2 China Agricultural University, 3
Ohio State University Point of Contact:
Teng Teeh Lim, email@example.com
The information provided here was developed for the conference Mitigating Air Emissions From Animal Feeding Operations Conference held in May 2008. To obtain updates, readers are encouraged to contact the author.