ammonia mitigation and capture as a liquid fertilizer from manure using gas-permeable membrane
DESCRIPTION
Proceedings available at: http://www.extension.org/67655 Excessive emissions of ammonia (NH3 ) from animal manure negatively impact the environment with potential to pollute air, soil and water, and produce malodors. The objective of this study was to assess NH3 mitigation from liquid dairy manure (LM) using tubular acid-filled gas-permeable membranes (GPM) in laboratory experiments; and, to evaluate the possibility of scaling up the NH3 mitigation system for use on AFOs.TRANSCRIPT
Ammonia Mitigation and Capture as a Liquid Fertilizer from Manure Using Gas-Permeable
Membrane
Saqib MukhtarProfessor and Extension Ag. Engineer
Amir M. Samani MajdPhD Candidate,
Biological & Agricultural Engineering Department, Texas A & M University System
Waste to Worth Conference, Hyatt Hotel, Denver, CO. April 1-5, 2013
IntroductionAnimal Manure NH3 Loss into the air
• Loss of a Valuable Nutrient for Plants
• Environmental Issue
• Capturing and Recovery???????
2NH3 + H2SO4 (NH4)2SO2
NH3 and NH4+
• NH3
• NH+4
pH Influences Forms of Ammoniacal N
Ammonium (NH4)
Ammonia (NH3)
Ammonia Mitigation Approaches & Technologies
• Acidic solution-sprayed scrubbers Studies underway in our laboratory
• Bio-filters (compost, straw etc.)• Chemicals like acidified clays and
sodium hydrogen sulfate• Gas-permeable membrane (GPM)
Gas-permeable Membrane
• ePTFE: expanded Polytetrafluoroethylene
(AKA Dental Floss)
Methods and MaterialsGPM Properties
Type of membrane Used ePTFE
Inside Diameter (cm) 0.672Outside Diameter (cm) 0.80Flat Width (cm) 1.25Wall Thickness (cm) 0.066Porosity (%) 83
Mean Pore Diameter(μm) 2.401±0.142Pore size 100X magnification
TAN
Mechanism
NH3 (Gas)
(NH4)2SO4
Capture
Acid-filled GPM
Liquid manure
Ammonia
(NH4)2SO4
Experimental Set-upGlass wool filled Orifice
Sampling Orifice
Acidic Solution (Jar)
Acidic Solution (Jar)
PeristalticPump
LM Chamber
GPM
Sampling Orifice
LM Chambers
Liquid Manure Chambers
Experiment
Chamber Inside Dimensions Depth of LM in chamber
(cm)
Manure volume (L)
Headspace volume(L)Length
(cm)Width (cm)
Height (cm)
Surface area(cm2)
1X - 7.7* 23 186 16.2 3 1.3
2 X 19.1 19.1 29 365 16.2 5.9 4.7
4 X 29.2 25.4 29 742 16.2 12 9.5
8X 40.6 35.6 30 1445 16.2 23.4 19.9
* This entry is radius (cm) of the 1X cylindrical jar.
Raw Manure, Collection, Sampling & Measurements
Experimental Set-up
Treatment chamberControl chamber
Acidic flasks
Peristaltic pump
Results and Discussion: Feasibility
Concentration of NH3-N in acid and LM
4X Control Chamber
1X Chamber
2X Chamber
pH of LM
pH of LM
NH3-N in
Acid
NH3-N in LM
pH of acid
pH of LM
NH3-N in
Acid NH3-N in LM
pH of acid
Results and Discussion : Feasibility
Concentration of NH3–N in acid and LM
4X Control Chamber
4X Chamber
8X Chamber
pH of LM
NH3-N in
Acid NH3-N in LMpH of acid
pH of LM
NH3-N in
Acid NH3-N in LM
pH of acid
pH of LM
NH3-N in LM
Part 2: Diluted H2SO4 solutions
• It is safer for handling and operation
• Lesser contamination of LM if the tube is ruptured
• Acid solution pH rises faster-Closer to the pH of common Ammonium Sulfate fertilizer (between 5.5 and 6)
• Diluted acid means less cost
Experiments (All 4X chambers)
Nominal pH Time (days)
Initial pH of the acids (H2SO4 )
Submerged GPM Suspended GPM
Low pH* 18 0.32 0.36pH 2 7 2.12 2.14pH 3 7 3.08 3.07pH4 7 4.11 4.14pH 5 7 5.42 5.36
*Previous experiment
Quick pH increasepH 5 Experiment
NH3 concentrations in different diluted acidic solutions
• Feasibility: The tubular GPM system filled with acidic solution did extract NH3 from LM.
• Efficiency: The 4X experiment was the most effective, with greatest removal and capture efficiency.
• Practical Finding: One cm2 surface area of GPM was needed to treat nearly three cm2 surface area of liquid dairy manure.
Conclusions
Conclusions
• As compared to low pH acidic solution, NH3
removal efficiency was reduced considerably due to a quick increase in pH of all diluted acids.
• Should maintain acid solution at pH 2 or less during experiments for an efficient and higher rate of ammonia removal.
Submerged GPM system
pH controller and dosing system
Circulation pump
Pressure gauge and pressure controller
Solar panels for power supply to pump and acid dosing system
Acidic solution circulating through the GPM system
Scaled-Up GPM System
Ammonia Concentration in Acidic Solution after 24 Hours of Extraction
Average Hourly NH3 Conc. (mg/l) in acidic solution
40 85 190 280 Flow Rate (ml/min)
Acknowledgement
Funding for this study was provided through a grant 2009-34466-20025 by the United States Department of Agriculture: National Institute for Food and Agriculture (UDSA- NIFA)
Thanks for your attention.
Questions