The Design and Development of an Experimental Anaerobic Digester for Organic Waste

THE DESIGN AND DEVELOPMENT OF AN EXPERIMENTAL ANAEROBIC DIGESTER FOR ORGANIC WASTE

Sponsoring Institution

National Institute of Food and Agriculture

Project Status

COMPLETE

Funding Source

HATCH

Reporting Frequency

Annual

Accession No.

0217691

Grant No.

(N/A)

Cumulative Award Amt.

(N/A)

Proposal No.

(N/A)

Multistate No.

(N/A)

Project Start Date

Apr 16, 2009

Project End Date

Apr 16, 2012

Grant Year

(N/A)

Program Code

[(N/A)]- (N/A)

Project Director
Ososanya, E.

Recipient Organization
UNIV OF THE DISTRICT OF COLUMBIA
4200 CONNECTICUT AVENUE N.W
WASHINGTON,DC 20008

Performing Department
SCHOOL OF ENGINEERING & APPLIED SCIENCE

Non Technical Summary
The ever growing demand for energy world-wide can only be met by considering the possible range of energy solutions, and the technology to produce emerging sources of energy, to reduce our dependence on oil - a non renewable fossil fuel. Renewable energy such as solar, wind, geothermal, biomass [1,2,3,4], and alternative fuels are promising clean energy resources of the future, which are environmentally friendly and which sources replenish itself or cannot be exhausted. Biomass energy is derived from waste of various human and natural activities, including, municipal solid waste, manufacturing waste, agricultural crops waste, woodchips, dead trees, leaves, livestock manure, hotels and restaurant wastes, etc., which are abundant anywhere and everywhere, at any time. Any of these sources can be used to fuel biomass energy production with the design of an efficient digester or processing plant to harness the energy from the biological mass. By designing and building a new Anaerobic Digester, a number of possible solutions to alternate energy can be experimented which include digestion of animal waste, organic wastes, and bio wastes. This study also will research the use of alternate fuel for the District of Columbia Taxi Cabs.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
511	5399	2020	20%
402	5399	2020	30%
403	5310	2020	50%

Knowledge Area
511 - New and Improved Non-Food Products and Processes; 403 - Waste Disposal, Recycling, and Reuse; 402 - Engineering Systems and Equipment;

Subject Of Investigation
5399 - Structures, facilities, and equipment, general/other; 5310 - Machinery and equipment;

Field Of Science
2020 - Engineering;

Keywords

Goals / Objectives
This research will build a pilot waste anaerobic digester at the DC Agricultural Experiment Station Research Center in Beltsville, Maryland for the production of biomass and demonstrates that using the resources that are easily available makes the production of energy efficient and reliable. The energy producing potential of the different types of waste products will be studied through continuous monitoring of the digestion biochemical processes, operating parameters, the energy content, and the analysis of the biogas products. A Fuzzy logic Controller of the Anaerobic Digester System will be designed in parallel with the physical digester to enable us to model mathematically or simulate certain aspects of the digester processes for increased efficiency and process stability. This study will also research the environmental impact of the use of alternate fuels by performing an engineering analysis of energy consumption by Taxi Cabs in the District of Columbia. The goal will be to evaluate the differential environmental impacts of various types of fuels used by the taxi cabs and to answer two questions: What are the advantages of having an alternate fuel for District taxi cabs Are there any potential environmental benefits through the use of biofuels by DC taxi cabs The objectives of this research are: (i) To design and engineer an efficient, reliable, and low-cost anaerobic digester for waste processing; (ii) To analyze the potential of biogas production from anaerobic digestion of the organic waste of the city of Washington DC; and (iii) To maximize methane gas production. The overall objectives of environmental impact analysis will include: (a) Collect data and catalog the number of taxi cabs in the District and their fuel consumption patterns, number of fuel service stations, and types of fuel; (b) Conduct statistical analysis of collected data; (c) Relate urban air quality to different types of fuel consumption; (d)Evaluate the impact of alternative fuel on the environment; (e) Conduct preliminary cost-benefit analysis of using biofuel; (f) Educate the stake holders and students about the use of alternative fuels; and (g) Support state and federal agencies in providing relevant information.

Project Methods
(i) Methane gas production: There are 4 stages in the digestion process[3,4] that will be closely monitored to boost the methane gas production: 1. The Hydrolysis process; where waste material reacts with water in the absence of oxygen, converting the Carbohydrates, Fats, and Proteins in the waste products to Sugars, Fatty acids, and Amino acids; 2. Acidogenic process; where acidogeneous bacteria convert sugars into CO2, H2, and Ammonia; 3. Acetogenic process; where acetogeneous bacteria convert the products to Acetic acid; and 4. Methanogenic process; where methanogeneous bacteria converts Acetic acid to CH4 and CO2. Key considerations in the design of an anaerobic digester include the amount of water and inorganic solids that mix with waste during collection and handling. The anaerobic digester itself is an engineered containment vessel designed to exclude air and promote growth of methanogenic bacteria. Biogas formed in the anaerobic digester bubbles to the surface where it is captured in gas collectors. To achieve higher gas production per feed, the environment inside the digester has to be made comfortable for the bacteria. Anaerobic bacteria are known best to survive at 35 degree centigrade (95 degree Fahrenheit); therefore, the temperature of the digester should be around this temperature. The higher the temperature the more chance that the bacteria will die; thus, resulting in less gas production. If the temperature is too low, the bacteria will become dormant and less gas production. In addition to balancing the temperature, the best gas production in the digester also depends on the acidity and alkalinity of the digester. Acid forming bacteria produce acid and lower the PH, while the methanogeneous bacteria increase the PH. The best PH for both of the bacteria to produce maximum gas will have to be determined through constant monitoring of the chemical processes in the digestion stages. If the amount of acid in the digester is too high that means there are a greater number of acid forming bacteria (acidifiers) than methane forming bacteria's(methanogeneous). (ii) Preliminary design of the Anaerobic digester assembly: The Reengineering drawing of the digester to be constructed is shown in figure 1: The 50-gallon digester is cylindrical, with a height of 6ft and diameter of approximately 6ft, with estimated mass volume of 172 cu ft.

Progress 04/16/09 to 04/16/12

Outputs
OUTPUTS: The anaerobic digestor (AnD) of organic waste processing started in the academic year 2009/2010 with the goal of designing and building 1000 gallons AnD equipped with sensors to monitor all parameters effecting operation and with a fuzzy logic controller to automate the control of the system parameters. Significant efforts were made to design the 1000 Gallon tank of the AnD; however, due to budget constraints, the design of the digestor's tank was scaled down to 75 gallons and scaled back again to 35 gallons. A comprehensive literature search was conducted to find the most efficient types and designs of a small AnD. The completed design splits AnD into two main parts: Mixer and Housing. The completed pro-engineering design of the digester can be summarized as follows: for the Mixer part, the following activities have been completed a) Defining the overall specification of the mixer; b) Developing the kinematic drawing of the mixer; c) Defining the main components such as gears, and mixing blades; d) The design of the mixing mechanism; e) The design of the automated feeding mechanism; and f) A comprehensive velocity analysis for the mixing mechanism. For the digester Housing the following activities have been completed a) Selection of the main elements of the Housing and the types of material needed for their construction and designing a window to monitor the level of the waste inside the tank; b) Designing the Housing Skelton; c) Theoretical evaluation of the fluid dynamics inside the digester tank; d) Simulation analysis of evaluate the stresses, exerted by the waste, inside the inner tank using the finite element analysis method and approximating the geometry of the entire tank with stress elements (tetrahedrons; e) Calculating the dimensions of the final metal sheets needed for the tank construction; f) Defining the features of the tank including the types of insulation, temperature and pressure sensors needed, locations of the sensors, and the automatic feeding system. In addition, the energy content of Bio-gas from various animals (Livestock wastes) was studied and the anticipated Gas yield compared. The study showed that the estimated gross energy content of approximately 30,000 Btu/head/day for dairy cow manure was two to three orders of magnitude higher than other animal waste products. The Net energy content; however, will be dependent on the operating performance of the digester. Thermodynamics Analysis was done to calculate the Combustion of Methane gas and the heat exchange during the reaction. Our calculation shows that 1kg of Organic Material will produce 27.748 MJoules of heat energy. PARTICIPANTS: Students Research Assistants: Ashish Bhandari Senior-level student, Electrical Engineering; Cisse Mademma Senior-level student, Mechanical Engineering; Ismael DJibril Senior-level student, Mechanical Engineering; Mekonnen Hailegiorgis, Senior-level student, Mechanical Engineering; Faculty Research Mentors: Esther T. Ososanya Professor, Electrical Engineering; Wagdy Mahmoud, Associate Professor, Electrical Engineering; Abiose Adebayo, Professor and Chair, Mechanical & Civil Engineering Department; Pradeep Behera, Associate Professor, Civil Engineering; Xueging Song, Associate Professor, Chemistry TARGET AUDIENCES: Presentations made for this project targeted professionals attending Energy Conversions and Education Conferences such as the American Society for Engineering Education (ASEE). Various outreach presentations were also given to High School students from the DC Public Schools. In addition, yearly seminar lectures were given to professionals from the community visiting the University and to Undergraduate students participating in the Undergraduate STEM research activities. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Simulation tools and simulation benchmarks were used to evaluate and compare different sludge control strategies used to improve the efficiencies of the biological reaction processes and to reduce their operational and environmental costs. The Operational parameters affecting the anaerobic digestion process include: a. Temperature of the digester: Anaerobic digestion will operate over a wide range of temperatures. However, there are two temperatures ranges where the digestion is most rapid, mesophilic (about 35 degree C) and thermophilic (about 55 degree C); b. Pressure: the excess gas pressure inside the digester can exceed the maximum design pressure and damage the cover or its mountings; c. The pH value: The pH value is especially critical in anaerobic digestion where important quantities of protons are released, eventually leading to acidification and process failure; d. The presence of nutrients in the digester; e. Concentration of volatile fatty acid (VFA) if present and its consistency; f. The retention rate of waste materials; g. Presence of toxic materials Various commercially-available sensors for the Monitoring System were evaluated. Different types of sensors were selected as follows: a) Temperature sensors: The selected sensors are 100 ohm RTD sensors in a 4-wire, Teflon insulated configuration. This provides an operating temperature range of -50 to 250 degree C. Fiberglass insulated wire is also available. b) Pressure sensors: Industrial Process Pressure Gauges with 4 and one half and 6-inch Dials Black Phenol (PGH Series) or Aluminum (PGJ Series) Case. c) Non-Contact ultrasonic liquid-level sensors: LVU40 series in conjunction with a PLC (programmable logic controller) they can be used for point level measurement. d) Flow of gas sensors: The digital thermal mass flow meters types FMA-1600A and FVL-1600A Series mass and volumetric flow meters can be used to determine the mass flow rate. e) pH electrodes: Cole-Parmer (registered trademark) Fast-Response Autoclavable Fermentation pH Electrodes can be used for pH ranging from 0 to 14. The estimated cost for the fabrication of these digestors in a bio-refinary design company ranges from $52,000 (35 gallons tank) to $1,000,000 (1000 gallon tank). More results are found in publication #3. The research team was successful in obtaining an NSF grant to develop Renewable Energy Course Curriculum that includes anaerobic digestion. The list of Renewable Energy courses that were developed and currently been offered includes a new University General Ed course (IGED 260 Discovery Science) and Introduction to Engineering course, CCEN 101, for engineering majors at Freshman level.

Publications

Ososanya, E., Mahmoud, W., Lakeou, S., Ukaegbu A., Kamdem, R., (2010). Design and Implementation of a Virtual Web-based Power Measurement Module for a Hybrid Renewable Energy Power System, Proceedings of the ASEE Annual Conference and Exposition, AC 2010-1992, Louisville, Kentucky, June 22-23, 2010.
Zhang, Nian; Kamdem, Roland; Ososanya, Esther; Mahmoud, Wagdy; Liu, Wenxin; (2010). VHDL implementation of the hybrid fuzzy logic controllers with FPGA. IEEE Xplore, Intelligent Control and Information Processing (ICICIP), 2010 International Conference on Digital Object; Identifier: 10.1109/ICICIP.2010.5564277, 2010 , Page(s): 5 - 10.
W. Mahmoud, E. Ososanya, P. Behera, A. Adebayo, and X. Song, Anaerobic Digestor of Organic Waste Processing: A Biomass Energy Production Project, AC 2012-3784, American Society for Engineering Education, 2012 Conference Proceedings, June 2012.

Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: The major accomplishments in this reporting period include: a) a feasibility of the design and implementation of an operational digester, the monitoring and control of the different biodegradation process variables and experiments to boost or maximize the gas production was conducted; b) The design and evaluation of a lab-scale anaerobic digestor. The goal of the feasibility study was to get an understanding on the characteristics of organic waste from hotels and restaurants and study the feasibility of implementing the proposed anaerobic digester for biogas production for District of Columbia hotels and restaurants. The specific research objectives of the study include a) Understanding of organic waste collection methods in hotels and restaurants; and b) Possible quantification of organic waste. The feasibility study research methodologies include: a) Preparation of survey questioner to collect the data about the current generation and waste processing of organic waste from a variety of sources; b) Implementation of survey through site visits; c) Quantification of daily organic waste and evaluation of waste processing through the experimental anaerobic digester. The goal for designing a lab-scale anaerobic digestor was to build a mini anaerobic digester that can generate biogas in the laboratory and to provide preliminary data and identify key aspects of the design for an efficient, reliable, and low-cost anaerobic digester for waste processing. The specific research objectives the lab-scale digester include: a) The design of a small scale anaerobic digester that can be operated with a minimum of monitoring; b) Regulating, and adjusting and optimization of the experimental condition to maximize the amount of biogas produced per unit time with the proposed mini digester. The research methodologies for the small-scale anaerobic digestor include: a) Design and fabrication of laboratory scale mini anaerobic digester; b) Analysis of the content of the biogas produced by the proposed mini digester using Gas. PARTICIPANTS: Students Research Assistants: Cisse Mademba, Senior-level student, Mechanical Engineering; Ismael DJibril, Senior-level student, Mechanical Engineering; Faculty Research Mentors: Esther T. Ososanya Professor, Electrical and Computer Engineering; Wagdy Mahmoud, Associate Professor, Electrical and Computer Engineering; Abiose Adebayo, Professor and Chair, Mechanical & Civil Engineering Department; Pradeep Behera Associate Professor, Civil Engineering; and Xueging Song, Associate Professor, Chemistry TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
A feasibility study was conducted to implement an anaerobic digester for biogas production for District of Columbia hotels and restaurants. The results of the feasibility study are as follows: a) Washington D.C. is one of the nation's most popular tourist destinations, attracting nearly 20 million visitors annually; b) In the District, there are approximately a total of 230 hotels, bread & breakfast inns, lodgings and vacation rental and more than 1200 hotels and restaurants. Food Waste is the single largest component of the waste stream by weight in the United States. Americans throw away about 43.6 million tons of food each year; c)According to the American Hotel and Motel Association (AHMA), 25-30% of the total waste stream generated by the hotel industry is food waste; and d) The quantity and the composition of waste generated by restaurants depends on the size of the restaurant, the type of the restaurant, and number of meals served. Restaurants with sit-down style dining have nearly twice the proportion of food waste in their waste stream. Sit-down restaurants tend to prepare most menu items fresh, and therefore, have more preparation waste. In order to understand the ways that organic waste is collected and to quantify the daily organic waste, a survey questionnaire was prepared. A significant effort was made to collect this data; however, with little success. Only few hotels agreed to participate and to provide the data. The most important finding is that organic waste had to be collected in separate bins; it is currently mixed with inorganic waste. Therefore, the project must design separate bins for organic waste collection and education is required for implementation. Initially, we proposed to use organic wastes from hotels and restaurants in the Washington DC Metropolitan area; however, very limited number of hotels or restaurants are willing to participate in this program. Therefore, we had to use cow manure as the feedstock. Cow manure was collected at one of the facilities of CMREC (Central Maryland Research and Education Center) at Clarksville. Based on solid content, two different cow manures used in this project were collected from this site: a) Raw Manure (8-25% solids); and b) Liquid Manure containing less than 3% solid. Biogas was produced when cow manures with different solid content were used. The biological reactions of the different species in a single stage reactor can be in direct competition with each other. For this reason, biogas production under different conditions is not presented. However, some preliminary conclusions were summarized: 1) Low cost and low maintenance mini Anaerobic digesters were successfully built and used to produce biogas from raw manure and liquid manure; 2) For all biogas samples produced by the mini digester, methane content ranges from 46.9% to 64.6%;and 3) Preliminary data shows that raw manures are a better source for the mini digester to produce biogas than liquid manure (produces biogas faster with more methane content).

Publications

Ososanya, E., Mahmoud, W., Behera, P., Song, X., and Adebayo, Anaerobic Digester of Organic Waste Processing: A Biomass Energy Production Project, Submitted to the 2012 ASEE Annual Conference and Exposition.

Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: The research efforts in this reporting period concentrated on analyzing and comparing the energy content and anticipated Gas yield of Bio-gas from various animals (Livestock wastes). The results of this study were used to complete the following tasks: Scaling of the digester tank designs to fit Home energy use; engineering drawings of the digester tank designs; Obtaining quotes for fabrication costs in the range from $7,875 (for 35 gallons tank) to $152,500 (for 100 gallons tank); selection of sensors for the Monitoring system to include: 1) Selection of Temperature Sensors: The selected sensors are 100 ohm RTD sensors in a 4-wire, Teflon insulated configuration. This provides an operating temperature range of -50 to 250 degrees C. Fiberglass insulated wire is also available. Bayonet temperature sensors are commonly used in industries. 2) Selection of Pressure Gauge - Industrial Process: Pressure Gauges with 4 and one-half and 6-inch Dials Black Phenol (PGH Series) or Aluminum (PGJ Series) case are being considered. 3) Liquid Level Monitoring: A Non-contact Ultrasonic level sensors such as the LVU40 Series sensors in conjunction with a PLC (programmable logic controller) are found to be suitable and accurate for point level measurements. 4) Gas flow sensors: A digital thermal mass flow-meter such as the FMA-1600A and FVL-1600A Series mass and volumetric flow meters are found to be suitable to determine the mass flow rate. 5) Selection of pH Electrodes: The Cole-Parmerr Fast-Response Autoclavable Fermentation pH Electrodes provides confident values over the entire pH range from 0 to 14. It can also operate at high temperatures up to 266 degrees F (130 degrees C). Dissemination: The Anaerobic Digestor project research group participated in the UDC Agricultural Experiment Station Research Seminar in September 2010, and gave a presentation titled: "The Design of an Experimental Anaerobic Digestor for Organic Waste Processing" - Phase II detailing the work done to date. The research team was successful in writing and obtaining two external grants in Renewable Energy Course Curriculum Development and Instrumentation grant from the National Science Foundation (NSF), during the 2010 academic year. PARTICIPANTS: Students Research Assistants: Ashish Bhandari, Senior-level student, Electrical Engineering; Cisse Mademba, Senior-level student, Mechanical Engineering; Ismael DJibril, Senior-level student, Mechanical Engineering Faculty Research Mentors: Esther T. Ososanya, Professor, Electrical and Computer Engineering; Wagdy Mahmoud, Associate Professor, Electrical and Computer Engineering; Abiose Adebayo, Professor and Chair, Mechanical & Civil Engineering Department; Pradeep Behera, Associate Professor, Civil Engineering; Xueging Song,Associate Professor, Chemistry TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Anaerobic Digestor Process Simulation System: Evaluation of simulation tools and simulation benchmarks used to evaluate and compare different sludge control strategies. These tools include the IWA/COST, the quantitative Risk Assessment module, and the Anaerobic Digestion Model No.1. Simulation models will used to simulate the practice of sludge treatment in order to increase the efficiencies of the biological reaction processes, and to reduce their operational and environmental costs. The results of these simulations will be used to develop better sensors, effective control systems and better designs for the physical anaerobic digestion system. The anaerobic digestion process: Operational parameters affecting the anaerobic digestion process performance include: Temperature of the digester; pH value Stability; presence of nutrients in the digester concentration if present and its consistency; concentration of volatile fatty acid (VFA); retention rate of waste materials; and presence of toxic materials. The anaerobic digestion Simulation System: A fuzzy-logic based controller system will be designed to optimize the operation of the anaerobic digestion System in terms of operational cost, produce energy, and quality of the residual organic matter. The controller will control the concentration of VFA in the digester system through the manipulation of the input flow rate. The development of this fuzzy controller will help us develop better designs for digestion reactors and its data acquisition sensors. A set of fuzzy rules to control the input flow rate and to control the concentration of VFA, the concentration of chemical oxygen demand (COD), and digester operating temperatures are being created. The chemical equations of the digestion and waste conversion processes are being converted into mathematical operations and textual forms suitable for the creation of the fuzzy rules and the knowledge rules.

Publications

Ososanya, E., Mahmoud, W., Lakeou, S., Ukaegbu A., Kamdem, R., "Design and Implementation of a Virtual Web-based Power Measurement Module for a Hybrid Renewable Energy Power System", Proceedings of the ASEE Annual Conference and Exposition, AC 2010-1992, Louisville, Kentucky, June 22-23, 2010
Cotae, Paul, Ososanya, Esther, Kemathe, Lily, Suresh Regmi, and Patrice Kamdem, "Teaching Wireless Sensors Network Through Laboratory Experiments", Proceedings of the ASEE Annual Conference and Exposition, AC 2010-2417 , Louisville, Kentucky, June 22-23, 2010
Zhang, Nian; Kamdem, Roland; Ososanya, Esther; Mahmoud, Wagdy; Liu, Wenxin; "VHDL implementation of the hybrid fuzzy logic controllers with FPGA" IEEE Xplore, Intelligent Control and Information Processing (ICICIP), 2010 International Conference on Digital Object; Identifier: 10.1109/ICICIP.2010.5564277, 2010 , Page(s): 5 - 10

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: The Research efforts in this reporting period concentrated on scaling down the 1000 gallons anaerobic digestor tank design to a smaller 75 gallons tank because of budget constraints. The proposed anaerobic digestor will be made of two major parts, Housing and Mixer. The overall design of the digester has been completed. A comprehensive literature search was conducted to find the most efficient types and designs of a small anaerobic digester. The following report details of completed pro-engineering design activities for the digester. For the Mixer part, the following activities have been completed: a)Defining the overall specification of the mixer; b)Developing the kinematic drawing of the mixer; c)Defining the main components such as sun and planetary gears, and mixing blades need for the mixer construction; d)The design of the mixing mechanism; and e)A comprehensive velocity analysis for the mixing mechanism including the movements of the mixer blades, the calculation of the sun/planetary gear ratios, finding the expression of the velocity at the edges of the gear teeth, calculating the maximum total area of the blade in contact with the waste and finding the drag forces on the blades due to such contacts. For the digester housing the following activities have been completed: a)The kinematic drawing of the Housing including support, inner and outer sheets; b)Sizing of the Housing, i.e., height and radius; c)Producing a 3D rendering of the Housing; d)Selection of the main elements of the Housing and the types of material needed for their construction and designing a window to monitor the level of the waste inside the tank; e)Designing the Housing Skelton (lower and upper parts, support, and hooks) and the thicknesses of metal sheets; f)Theoretical evaluation of the fluid dynamics inside the digester tank; g)Simulation analysis of evaluate the stresses, exerted by the waste, inside the inner tank using the finite element analysis method and approximating the geometry of the entire tank with stress elements (tetrahedrons); h)Calculating the dimensions of the final metal sheets needed for the tank construction and the distance between the two layers; and i)Defining the features of the tank including the types of insulation, temperature and pressure sensors needed, locations of the sensors, and the automatic feeding system. The following activities are still work in progress: a)Designing the automatic feeding system for the digester; and b)Producing the final drawing and construction specifications needed for the digester fabrication in a bio-refinery design company. PARTICIPANTS: Students Research Assistants: Ashish Bhandari, Senior-level student, Electrical Engineering; and Cisse Mademma, Senior-level student, Mechanical Engineering. Esther T. Ososanya, Professor, Electrical Engineering; Wagdy Mahmoud, Associate Professor, Electrical Engineering; Abiose Adebayo, Professor and Chair, Mechanical & Civil Engineering Department; Pradeep Behera, Associate Professor, Civil Engineering; and Xueging Song, Associate Professor, Chemistry TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Anaerobic Digestor Process Simulation System Evaluation of simulation tools and simulation benchmarks used to evaluate and compare different sludge control strategies. These tools include the IWA/COST, the quantitative Risk Assessment module, and the Anaerobic Digestion Model No.1. Simulation models will used to simulate the practice of sludge treatment in order to increase the efficiencies of the biological reaction processes, and to reduce their operational and environmental costs. The results of these simulations will be used to develop better sensors, effective control systems and better designs for the physical anaerobic digestion system. The anaerobic digestion process: Operational parameters effecting the anaerobic digestion process include: Temperature of the digester, The pH value, Stability, The presence of nutrients in the digester - concentration if present and its consistency, The concentration of volatile fatty acid (VFA), The retention rate of waste materials,and presence of toxic materials. The anaerobic digestion Simulation System: A fuzzy-logic based controller system will be designed to optimize the operation of the anaerobic digestion System in terms of operational cost, the produce energy, and the quality of the residual organic matter. The controller will control the concentration of VFA in the digester system through the manipulation of the input flow rate. The development of this fuzzy controller will help us develop better designs for digestion reactors and its data acquisition sensors. A set of fuzzy rules to control the input flow rate and to control the concentration of VFA, the concentration of chemical oxygen demand (COD), and digester operating temperatures are being created. The chemical equations of the digestion and waste conversion processes are being converted into mathematical operations and textual forms suitable for the creation of the fuzzy rules and the knowledge rules. The design of the anaerobic digestor simulator is work in progress. Dissemination: The Anaerobic Digestor research group participated in the UDC Agricultural Research Center Seminar in September 2009, and gave a presentation titled: "The Design of an Experimental Anaerobic Digestor for Organic Waste Processing" detailing the work done to date. The project team submitted a Letter of Intent in November 2009 for the Northeast SUN GRANT INITIATIVES and are currently working on submitting a full proposal in February for External Funding.

Publications

No publications reported this period