Climate Friendly Farming

Transcription

1 METU Climate Friendly Farming WSU-Biological Systems Engineering WSU-Center for Sustaining Agriculture and Natural Resources WSU-Cooperative Extension WSU-Crop and Soil Sciences WSU-Agricultural Economics WSU-Economic Sciences WSU-Renewables and Engineering Division USDA-Land Management and Conservation Unit METU-Environmental Engineering Dr. Göksel N. Demirer Department of Environmental Engineering

2 Background Ankara Climate Change Conference OVERVIEW Agriculture affects the condition of the environment in many ways, including nutrient enrichment of surface and ground waters, contamination of drinking water supplies, and odors, oxygen depletion, and impacts on global warming through the production of greenhouse gases. In 24, the US EPA estimated that agriculture contributed approximately 7% of the U.S. greenhouse gas emissions (in carbon equivalents, or CE), primarily as methane (CH4) and nitrous oxide (N2O). The agricultural sector is a relatively minor contributor to CO2 emissions. Nonetheless, agriculture constitutes 4 percent of anthropogenic sources of methane (GWP 21) primarily from rice and cattle production, and 68 percent of N2O (GWP 31) mainly from nitrogen fertilizer.

3 Carbon Sequestration Agriculture also has the potential, with new practices, to also act as a sink, tying up or sequestering CO2 from the atmosphere in the form of soil carbon Therefore, agriculture is both a receptor of possible climate changes arising from greenhouse gas emissions and a source of greenhouse gases. Climate Friendly Farms Moving from Source to Sink CH 4 CO 2 N 2 O REDUCE EMISSIONS CO 2 CO 2 INCREASE C SEQUESTRATION

4 Soil carbon is part of the global C pool Pool Amount of carbon (Gigatons) Atmosphere 75 Soil (organic) 14 Soil (inorganic) 93 Living vegetation 76 The amount of carbon in the soils of the earth is about 3 times the amount in the atmosphere Scientists believe increasing the amount of carbon sequestered into the soil can impact the global atmospheric CO 2 levels

5 What is carbon sequestration? Carbon sequestration can be defined as the net removal of CO 2 from the atmosphere into long-lived pools of carbon. In terrestrial ecosystems this would include... Soil organic C trees Governing Mechanisms: roots CO 2 removed from atmosphere by plants via photosynthesis Inorganic C deep in soils Plant material converted to organic matter through microbial biochemical reactions and stored in soil

6 Biofuels Combining Carbon sequestration with biofuel production: Ankara Climate Change Conference One of the ways of offsetting GHG emissions from agriculture is to increase production of commodities (fast growing trees and plants), which can serve as feedstocks (for electrical power plants or liquid fuel production) for the production of biofuels. Biofuel production contributes to reduction in net GHG emissions because: - As plant grows photosynthesis absorbs CO2 from atmosphere concentrating it in the feedstock - When burned this is released Thus biofuel use not only involves recycled carbon but also produces sustainable and renewable energy. Moreover, agricultural waste and residues also constitutes a significant source of biomass for biofuel production.

7 Nitrous oxide Agriculture alters the terrestrial nitrogen cycle as well. Through nitrogen fertilization, monocropping, and improper water management, nitrogen is more prone to being lost both to ground or surface water and the atmosphere. Nitrous oxide (N2O), a common emission from agricultural soils through fertilizer and manure application, is a potent greenhouse gas (GWP 31) that has increased its atmospheric concentration by 15% during the past two centuries. Methane Methane is derived from the decay of matter in the absence of oxygen. Primary sources of methane include animal digestive processes, wetlands, as well as manure storage and handling. About 65% of the methane in the atmosphere is attributable to agriculture, with a significant portion arising from dairy cows. Methane is about 21 times more potent as a greenhouse gas than CO2.

8 The Project Ankara Climate Change Conference Climate Friendly Farming To better understand agricultural sustainability within the context of climate change, Washington State University (WSU) the Center for Sustaining Agriculture and Natural Resources (CSANR) carries out the Climate Friendly Farms research and demonstration project. The goal of Climate Friendly Farms is to develop and implement systems and practices that maximize the potential for agriculture to mitigate global climate change. The Climate Friendly Farms primary focus will be to mitigate the global climate change by shifting agriculture from a net source (contributor) to a net sink (tie-up or sequestration) for greenhouse gas emissions.

9 The 5-year project will focus on dairy production, irrigated crop farming, and dryland grain farming, three farming systems of importance for Washington State and the world. The project goals are as follows: (1) assess the current situation regarding the global warming contribution of different farm systems; (2) develop strategies for changing the systems to maximize global warming mitigation; (3) evaluate the actual and potential mitigation through demonstration sites and computer modeling. The project approaches will include technology research and development socioeconomic analysis and systems modeling, on-farm implementation of demonstrations, and educational outreach.

10 Expected impacts of the project include the documentation of new technology, farm practices, and systems that can mitigate multiple environmental problems and lead to measurable improvements in greenhouse gas storage, water use, and nutrient cycling on farms. Key project tasks will include: development of an improved or enhanced anaerobic digester for treating dairy waste, development of farm nutrient management strategies and an associated decision support system for dairy farms, integration of reduced tillage and residue management to increase soil carbon storage, irrigation water management to improve N cycling, and outreach and education.

11 Dairy Farm Component Dairy farms are becoming more intensive (more animals per unit of land) in an effort to lower costs. This leads to more animal confinement, less land on which to spread an increasing nutrient load, and environmental problems with manure management. Most dairies now use some sort of manure lagoon for storage, a system that leads to emissions of methane, ammonia, and nitrous oxide. Anaerobic digesters are being explored as one promising alternative technology to manage manure. Digesters can capture methane for power generation and also produce a fiber by-product that can economically export nutrients. Barriers to this technology include capital costs, markets for the fiber, handling of the nutrient rich water by-product, and optimizing the biological processes.

12 The specific objectives for the dairy component of the project are: Utilize state-of-the-art anaerobic digestion to reduce greenhouse gas emissions, produce renewable energy, conserve nitrogen and carbon, and protect water quality. Evaluate the socioeconomic performance of a farm-scale digester, including capital costs, operational costs, revenues, regulatory compliance, farm management challenges, and potential economic impacts on the local community. Demonstrate the potential for a digester to improve farm performance through educational tours, presentations, publications, and the collection of actual operational data. Develop a new animal waste management model that features anaerobic digestion, nutrient recovery and decision optimization.

13 Climate Friendly Farm Enhanced Anaerobic Digester Team Dr. Chris Feise: Director, WSU CSANR Dr. Shulin Chen: Professor of Biological Systems Engineering Ankara Climate Change Conference Dr. Göksel Demirer: Professor of Env. Engineering at METU, Turkey Dr. Zhiyou Wen: Post-Doc Researcher in Biological Systems Engineering David Granatstein: Sustainable Agriculture Specialist, WSU CSANR Craig MacConnell: Extension Agent and Chair, WSU Cooperative Extension Chad Kruger: Director of Outreach and Communications, CFF CSANR Cary Swanson: Research Associate, Biological Systems Engineering Wei Liao: PhD student within Biological Systems Engineering Craig Frear: PhD student within Biological Systems Engineering

14 Facts Ankara Climate Change Conference Anaerobic Digestion (AD) is an established bioconversion technology for high strength wastewater treatment such as animal manure. It has several advantages such as eliminating pathogens and weed seeds, controlling odor, improving fertilizer value, and producing value added products such as energy rich methane. Extensive research has been conducted and well documented on the feasibility of anaerobic treatment of farm animal manure and its advantages, reactor types used, performance, etc. Conventional high-rate anaerobic reactors such as anaerobic filters, upflow anaerobic sludge blanket reactors, etc. cannot effectively process wastes containing more than 2-3% solids and are thus inappropriate for use with animal manures which have much higher solids content.

15 Role of AD on GHG Mitigation Ankara Climate Change Conference A Case Study for the Langerwerf (CA, USA) Dairy Waste Management System A 5-year full life cycle analysis (LCA) of GHG emissions was conducted on the AD System operated by the Langerwerf family of Durham, California. The GHG emissions from the AD System were compared with those that would have been released without the use of that system on the dairy farm. The livestock waste management system prior to installation of the AD System was considered the Reference System. The Langerwerf family currently operates a 4-cow dairy farm with a plug-flow AD System that produces electricity and hot water through the use of a biogas enginegenerator equipped with a heat recovery unit. The effluent from the digester is separated into solids and liquid fractions. The solids are used as bedding in freestalls and calf barns and as a soil conditioner. The wastewater is applied as fertilizer to a field of corn. The hot water from the engine is used for maintaining a temperature of 95 to 1 degrees F.in the anaerobic digester and for farm and domestic applications. Key components of the AD System are given in the following figure.

16 Operation of the System Ankara Climate Change Conference

17 GHG Emissions from AD and Reference Systems Comparison of GWP by type of Greenhouse Gas Total reduction achieved

18 Digester Type Batch CSTR CSTR PF CSTR Two stage ASBR** Batch CSTR TPAD*** PF Ankara Climate Change Conference Current Practice? Performance data for different anaerobic reactors treating dairy and cattle manure Substrate Type Dairy Manure Dairy manure Cattle manure Dairy manure Cattle waste Dairy manure Cattle manure Cattle manure Dairy manure Dairy manure HRT (days) Operating Temperature ( C) Loading Rate (g VS/L.day) Methane Content (%) Operation Methane Production (L/g VS added) VS Reducti on (%) Reference Batch.71* 4.8 Hills, Semicontinuous On alternate days Hills, * Hills, 1983 Hills and Mehlschau, Meso Daily fed Singh et al., Thermo- Meso 6 - Batch.1 22 Dugba et al., Batch Sánchez et al., Continuous Ahring et al., Thermoc- Meso * L/g VS destroyed ** ASBR: Anaerobic Sequencing Batch Reactor *** TPAD: Temperature-phased anaerobic digestion Semicontinuous Sung and Santha, Meso Continuous.77* 29.7 Martin et al., 23

19 There are several key areas of research that must be pursued if AD technology is to be made more economically advantageous. These include investigating AD s relatively low digestion rates (or high retention time requirements) and difficulties with biodegradation of lignocellulosic material. In other words, demonstrating innovative anaerobic process configurations that can process high solid animal waste at relatively short retention times will be an innovative step towards achieving effective exploitation of AD for animal manure, thus reduction in GHG emissions from farmlands. Some of the strategies adopted to this purpose: - Enzymatic pretreatment - Chemical pretreatment - Application of cellulose degrading pure cultures - Innovative reactor configurations (AHR, ABR, ALBR, high-rate liquid reactor, etc.) - Phase separation

20 Some of the strategies adopted to this purpose: - Enzymatic pretreatment -Chemical pretreatment -Application of cellulose degrading pure cultures -Innovative reactor configurations -(AHR, ABR, ALBR, high-rate liquid reactor, etc.) - Phase separation Inlet Flow Distributor Manure Biogas Collection QR1+Q R2 QR2 QR1 Outlet Biogas collection QR2 Leaching Bed Leachate UASB Reactor Recirculation Reactor Research in Improvements to Anaerobic Digestion Microbial Support Medium Gas Solid Separator Liquid level Gas deflector Granular Sludge Bed P Sampling Port Gas Meter Liquid Level Effluent Removal Port Support Media Influent Port Cross Shaped Gas Distributor Effective Volume=14.5 Liters

21 Average Daily Gas Production (L) Normalized Gas Production in R2 Average Daily Gas Production (L) Ankara Climate Change Conference Overview of Some Research Outcomes Effect of Phase Separation R1 R R1 R2 OLR (g VS/L.day) VS in the Feed (%) y= x r 2 =.976 y= x r 2 =.992 a c b This part of the research investigated the possible exploitation of the advantages of two-phase AD for unscreened dairy manure which could result in significant environmental and public health problems, as the first time. The results indicated that the use of a two-phase reactor at a SRT/HRT of 1 days (2 days acidogenic and 8 days methanogenic) for AD of dairy manure: - Resulted in 5 and 67% higher biogas production or volume reduction at OLRs of 5 and 6 g VS/L.day, respectively, relative to a conventional one-phase configuration with SRT/HRT of 2 days. - Made an elevated OLR of 12.6 g VS/L.day possible which was not achievable for conventional one-phase configuration.

22 Anaerobic Hybrid Reactor Based on the results of this part of the research, it can be postulated that that an AHR configuration incorporating floating support media for biomass immobilization and biogas recirculation for enhanced mixing can successfully used for the anaerobic digestion of dairy manure at high concentrations and loading rates. Namely an average methane production value of.191 L/g VS added was obtained at a significantly high loading rate (7.3 g VS/L.day) and low HRT value (15 days) which correspond to obvious cost reduction. Biogas Yield (L biogas/g VS added) Biogas Prod. (L/day) Biogas Recirc. (L/day) HRT (days) COD Load.Rate (g/l.day) VS in the Feed (%) Fed-batch Operation Continuous Operation a b c Flowrate = 75 ml/min Flowrate = 27 ml/min d 15 min/day 45 min/day 3 min/day 144 min/day e f Time (days)

23 Anaerobic Leaching Bed Reactor This part of the research indicated that LBRs can successfully be applied to anaerobic digestion of undiluted dairy manure with around 25% improvement in biogas production relative to conventional (slurry) anaerobic digesters. The improvement in the anaerobic digestibility of dairy manure in ALBRs is not limited to the increase in the biogas production. The rapid extraction and collection of the organic material contained in manure into leachate allows the application of high rate attached growth anaerobic reactor configurations such as anaerobic filters, upflow anaerobic sludge blanket reactors, etc. Average daily biogas production (ml) Average cumulative biogas production (ml) Time (days) COD (mg/l) BOD (mg/l) Concentration Biogas Corrected cumulative (mg/l) biogas production (ml) ph production in each BMP assay (ml) Ankara Climate Change Conference Time (days) Total Solids Volatile Solids a b c d e f

24 Cumulative gas (ml/bottle) Biogas production rate (ml/day Ankara Climate Change Conference Enzymatic Hydrolysis as pretreatment to AD Upon fungal cellulase production, the enzyme solution was used as enzyme source for hydrolysis of the fiber contained in the dairy manure. The enzymatic hydrolysis of manure fiber enhanced the biogas production of anaerobic digestion of dairy manure up to 35%. Enzyme addition also enhanced the biogas production rate Enzyme addition Time (day) 4 Enzyme addition (B) No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 No. 7 No. 1 No. 5 No. 6 No Time (day)

25 The proposed conceptual design based on the first 18 months of the research Development of a Next-Generation Anaerobic Digester Methane L HRM Digester Manure Manure Collection Solid/ Liquid Separator Effluent Fungal Reactor S Manure solids reactor Fiber

26 Thank you for your patience. Questions? Comments?