Steven A. Nyanzi Department of Chemistry Makerere University 29 th November 2013 Seminar Room, Department of Chemistry, College of Natural Sciences, Makerere University STRATEGIES FOR REDUCING GREENHOUSE GAS EMISSIONS FROM LIVESTOCK WASTES

OVERVIEW Background Livestock and GHG Emissions Approaches for reduction of NH 3 Emissions Emission reduction via urea recovery? Harvesting & stabilizing urea in urine Effect of Temp and pH on urea in urine Pre-concentration with an urease inhibitor Extraction of urea as clathrate Characterization Conclusion

Background on Climate Change Over 180 Countries are signatory to United Nations Framework Convention on Climate Change (UNFCC) by early 1990s UNFCC aims at stabilizing the conc’n of GHG in the atmosphere and reduce –ve impacts of climate change Green House Gases (GHG) include: CO 2, CH 4, N 2 O, Global Warming Potential (GWP): I kg CH 4 = 23 times CO 2 ; I kg N 2 O = 310 times CO 2

IPCC on NITROUS OXIDE IPCC Guidelines for estimating N 2 O emissions from agricultural systems 1) Direct emissions of N 2 O from agric fields 2) Direct emissions of N 2 O in animal production systems 3) Indirect emissions of N 2 O derived N used in agriculture IPCC Guidelines for National Greenhouse Gas Inventories (IPCC, 1997) excludes 2 and 3 !

Estimates of nitrous oxide emissions from agricultural systems worldwide, directly from agricultural fields (direct) from animal waste management systems (AWMS) and from indirect sources (indirect).

Livestock and GHG Emissions Uganda has one of the fastest growing population growth rate (3.3% per annum) Livestock = cattle, goats, sheep, pigs, chicken Cattle pop. in Uganda is about 11.4 million Cattle belching and fatting produce about 100 – 200 L of CH 4 per cow per day 90% of urea + other urea derivatives ((i.e., allantoin, uric acid) are excreted in animal urine Urea, Allantoin and Uric acid break down to produce CH 4, CO 2 and N 2 O

APPROACHES FOR REDUCTION OF NH 3 EMISSIONS A) Land application of animal manure B) Dietary manipulation of crude protein C) Use of animal feed diets containing tannins and polyphenols D) Use of additives to livestock wastes – a variety of additives including urease inhibitors

Emissions Reduction via Urea Recovery ? Urea 16 th most highly produced substance World production ~ 2.0 x10 8 tonnes/ year Applications :  Fertilizer (> 90%), Liu et al (2003)  Resins (melanine-formaldehyde, etc)  Supplementary protein source  Pharmaceutical, fermenting & brewing, petroleum industry, soap production  Hydrogen carrier (Renewable Energy) ! !

Harvesting & Stabilizing Urea in Urine Challenges in urine collection Enzymatic degradation of urea Production and control of stench Local materials as urease inhibitors Indigenous practices Environmental benefits –Less NH 3 emissions NH 3 emissions responsible FPM (d<2.5 μm) Improved Agricultural productivity - Fertilizers

Determination of Urea in Urine Colorimetric methods most widely used Indirect Methods: Determine products of urea e.g., NH 3 Berthelot reaction ( λ max 640 nm) Macro-method but NH 3 interferes Direct Methods : Determine urea directly i.e., Fearon’s method ( λ max 525 nm) Modified Fearon’s method (Nyanzi et al, 2010)

Pre-concentration Filter to remove solids Stabilization of urine extract at pH 9 Pass through bleaching material Heating extract at 96 O C for max 20 min Heating at < 96 O C for longer Conversion of allantoin to urea Use of a solar drier to reduce moisture

Urea-Hydrocarbon Clathrates Previous Applications: –Purify fatty acids from fats and vegetables –Separate straight chain from branched chain or cyclic compounds –Separate different petroleum fuel fractions Current Application –Use urea to extract FAs from plant oils ? –Use these FAs to extract urea from urine

Extraction of Urea as Clathrate Moles of HydrocarbonMolar proportion of urea in Complex Heptane (n-C 7 H 16 )6 Decane (n-C 10 H 22 )8.3 Hexadecane (n-C 16 H 34 )12 Octacosane (n-C 28 H 58 )21

n-Alkane-Urea complex: (a) cross section; (b) Hydrogen bonding (Courtesy of A. E. Smith)

Infrared spectra of: (a) extracted urea (b) pure urea

Urea from indigenous and Friesian cattle urine

Conclusion Reduction of GHG Emissions from livestock wastes is possible Urea stabilization, enrichment and extraction have lots of potential in odour control and urea production from livestock wastes! 3.08x103 tonnes urea could be recovered everyday! Production of urea from livestock wastes can create wealth, protect the environment & reduce ammonia emissions Sustainability through the process (Fertilizer - Animal feeds- Animal wastes-Urea)

A cow excreting liquid gold

Acknowledgement Organizers of this Interface Mr. G. Wamala Mr. Lubwama Mr. Magada Dr. J. Hawumba Dr. Emmanuel Tebandeke Mr. Hassan Kigozi Wasswa Mr. Christopher Biteinensha (FTIR spectra)

I THANK YOU