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Table of Contents 1 EXECUTIVE SUMMARY………………………………………………………………………………………4 2 INTRODUCTION………………………………………………………………………………………………..6

2.1 Problem Statement……………………………………………………………………………………..6 2.2 Broader Impacts………………………………………………………………………………………….7 2.3 Report Overview…………………………………………………………………………………………7

3 LITERATURE REVIEW……………………………………………………………………………………….8 4 SYSTEM REQUIREMENTS AND ANALYSIS………………………………………………………...13 4.1 Social Requirements………………………………………………………………………………….13 4.2 Environmental Requirements……………………………………………………………………14 4.3 Technical Requirements..…………………………………………………………………………..14 4.4 Economic Requirements……………………………………………………………………………14 4.5 System Analysis………………………………………………………………………………………...14 5 CONCEPTUAL DESIGN AND ANALYSIS……………………………………………………………..24

5.1 Concept Generation……………………………………………………………………………..........24 5.2 Concept Evaluation……………………………………………………………………………………31 5.3 Concept Selection……………………………………………………………………………………...34

6 PRELIMINARY DESIGN AND ANALYSIS…………………………………………………………....38

7 TESTING AND REFINEMENT……………………………………………………………………………40 8 DETAILED DESIGN AND ANALYSIS…………………………………………………………………..45 9 PROJECT MANAGEMENT…………………………………………………………………………………50

9.1 Team Management……………………………………………………………………………………50 9.2 Project Management………………………………………………………………………………….51

10 CONCLUSIONS AND RECOMMENDATIONS……………………………………………………..53 11 ACKNOWLEDGEMENTS…………………………………………………………………………………54 References………………………………………………………………………………………………………....54 Appendix 1: Box Models for Subsystems……………………………………………………………..58

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Appendix 2: Feedstock Sample Raw Data…………………………………………………………….59 Appendix 3: Other Concepts……………………………………………………………………………….60 Appendix 4: P3 Guidelines………………………………………………………………………………….65 Appendix 5: Bill of Materials……………………………………………………………………………….66 Appendix 6: Team Contract………………………………………………………………………………...67 Appendix 7: Engineering Drawings……………………………………………………………………..72 Appendix 8: Team Member Resumes…………………………………………………………………..79

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1 EXECUTIVE SUMMARY

Project Title

Design of an Anaerobic Digestion System for Use as an Alternative Food Waste

Disposal Method by JMU Campus Dining Facilities

Principal Investigator

Adebayo Ogundipe - ogundiaa@jmu.edu

Student Team

Kyle Groves - Undergraduate

Ciara Middleton - Undergraduate

Cairo Sherrell - Undergraduate

Will Steinhilber - Undergraduate

Institution

James Madison University - Harrisonburg, VA

Student Represented Departments and Institutions

James Madison University College of Integrated Science and Engineering

James Madison University Department of Engineering

Project Period and Location

This project began in September 2013 and ended on April 18, 2015. All project

affairs are conducted on the campus of James Madison University.

Total Project Amount

The total project amount is limited to a 1000 USD budget subjected to each team by

the James Madison University Department of Engineering.

Project Summary

Objective

Many JMU dining facilities located on campus manage food waste by disposing of it

in landfills. Biogas is produced as food waste naturally decomposes, and such biogas

may release into the atmosphere from a landfill and contribute to global warming.

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Biogas is majorly composed of methane that has a global warming potential 21

times greater than carbon dioxide (EPA, 2014). This report presents the design of a

system that may be implemented to reduce methane emissions in the food waste

disposal process used by campus dining facilities. Reducing methane emissions may

lessen the environmental footprint of campus dining on global warming. This

project is limited to designing a system that utilizes anaerobic digestion to reduce

methane emissions from the food waste disposal process used by East Campus

Dining Hall.

Description

The alternative food waste disposal system has been designed to reduce methane

emissions by capturing biogas generated from decomposing food waste. A finite

amount of food waste would be processed via anaerobic digestion within a reactor

satisfying anaerobic conditions. Biogas would be stored so that it can be used as a

renewable energy source where it can be converted to energy and emissions other

than methane; such as carbon dioxide, hydrogen sulfide, and trace gases.

This system would promote the planet by reducing global warming impacts of food

waste disposal processes utilized by JMU dining facilities. Prosperity would also be

promoted by providing biogas as a renewable energy source for use or sale.

Preventing biogas from entering the atmosphere would reduce air pollutants that

negatively influence human health to ultimately promote the lives of people.

Results

Analytical modeling adopted by the project team asserts that this alternative food

waste disposal system would annually produce 0.0657 kg of biogas capable of

providing 1210 btu per year for a value of 0.01 USD. Biogas production under

anaerobic conditions was verified by a proof-of-concept prototype that

demonstrated pressure build up within an air-tight reactor. An ignition test also

confirmed that biogas was present within the reactor.

The capital cost to install this system was totaled to be 2340 USD. Annual operation

cost of the system was calculated to be 1.32 USD for an estimated life of 5 years. A

completed bill of materials details the price, source, amount, and material

composition of each system component. In the event this system was implemented

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in East Campus Dining Hall, this bill of materials would be given to proper campus

authorities for assembly.

A computer aided draft of the system and its individual components has been drawn

to demonstrate the connections and dimensions of the system and system

components.

Contribution to Pollution Prevention or Control

Reducing methane emissions resulting from waste management practices will

lessen global warming impacts on the planet.

Supplemental Keywords

Anaerobic Digestion, Food Waste, Biogas, Methane, James Madison University

2 INTRODUCTION

2.1 Problem Statement

Food waste is transported from East Campus Dining Hall to landfills where waste

decomposes, which produces biogas that causes public health and safety concerns,

including surface migration, surface emissions, air pollution, and odor nuisance

(EPA, 2014). Food waste will instead be placed in a system where it is decomposed

via an anaerobic process, the result of which produces methane. The resultant gas

can then be used as a renewable energy source within the Harrisonburg and JMU

communities. This process also produces effluent that can be used as fertilizer on

local land, creating a more efficient process by utilizing all outputs of the system.

The project scope was to study the behavior of the food waste from E-Hall under

anaerobic conditions, ultimately designing a system that utilizes the waste to yield

methane gas. This was completed within the September 2013 to April 2015

timeframe at a cost not exceeding the $1,000 budget, allocated by the College of

Integrated Science and Engineering.

Project stakeholders include capstone advisor Dr. Adebayo Ogundipe, JMU Dining

Services, and the JMU community. The team was provided with resources such as a

project stipend, working facilities, and faculty to provide insight, direction, and

assistance in completing the project. External stakeholders are dependent upon the

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decision that is made concerning the use of the gas that is collected. The most

feasible option for implementation is use of the gas as an energy source. Effluent

that is a naturally produced byproduct of anaerobic digestion can be used as

fertilizer because it retains the nutritional value of raw materials introduced at the

onset of the digestion process to accelerate associated biological processes

(Hazeltine, 2003). The external stakeholders concerned with the effluent include

local farmers that will need a certain amount of fertilizer.

JMU dining services supplied food waste from E-Hall to the project team for study

and use. The amount of food waste that is generated directly affects the amount of

waste that can be processed to produce biogas for methane collection. Dr. Ogundipe,

provided insight and knowledge of anaerobic processes and systems to guide the

team in fulfilling the previously noted objectives.

Deliverables for the first year of the project included potential system designs, a

proof of concept, and future steps that would be taken toward the completion of the

project goals. Deliverables in the second year included a fully functional scale model

of the proposed system and plans for how the gas and effluent could be used if the

system were implemented. First year deliverables and all food waste testing were

completed by Friday May 9, 2014. Second year deliverables were completed by the

date of the Madison Engineering xChange, April 18, 2015. The duration of this

project was four semesters: Fall of 2013, spring and fall of 2014, and the project was

completed at the end of spring semester 2015 (20 months total).

2.2 Broader Impacts

Anaerobic digestion can be used in many situations to dispose of organic waste,

reducing the negative effects of landfill waste. If 5.5 million tons of food waste were

treated via the anaerobic digestion process, 477 to 761 GWh of electricity could be

generated each year (Gray, 2008). Compared to composting, it would save between

0.22 and 0.35 million tons of CO2 equivalent, assuming the displaced source is

natural gas-fired electricity generation (Gray, 2008). Possible future applications

include the use of similar systems in farming environments, especially chicken

farms. The digester would consume mainly animal waste to produce electricity or

heat for the farm in this scenario.

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2.3 Report Overview

The engineering design process consists of three phases. The team is closely

following each phase of this process in order to effectively and efficiently meet the

goals of the project. Phase 0 is the planning phase. In this report, it is reflected in the

Introduction and Literature Review sections. Phase 1 involves collection of

customer needs, investigating feasibility of concepts, and assessing production

feasibility. This phase is encompassed in the System Requirements and Analysis as

well as the Conceptual Design and Analysis section. Next, Phase 2 entails refining the

design, setting target costs, and defining major subsystems and interfaces. This is

highlighted in the Preliminary Design and Analysis and Testing and Refinement

sections of this report. Phase 3 of the design process includes choosing materials,

defining part geometry, and developing a financial plan. In terms of this project,

phase 3 is reflected in the Detailed Design and Analysis and Project Management

sections.

3 LITERATURE REVIEW

Process

Anaerobic digestion is the process that microorganisms go through to consume

organic material in an oxygen deficient environment. This process naturally takes

place at the bottom of oceans and lakes (Fergusen, 2006). Anaerobic digestion

results in the creation of a mixture of gases. This mixture of gases is often referred

to as “biogas”. Other products of anaerobic digestion include water and material that

the microorganisms did not consume. The remaining material is called digestate and

is composed primarily of lignin, cellulose, and remains of dead bacteria, but this

depends greatly on the composition of the feedstock (Markowski, 2014). Feedstock

is defined as an input of the digestion process which consists of the organic waste to

be consumed by the microorganisms. The general chemical equation where the

feedstock is converted into biogas is shown below as Equation 1.

This shows the initial input and final outputs of the processes that make up

anaerobic digestion which can be seen in Figure 1 below. There are four

interdependent processes that make up anaerobic digestion. These processes are

hydrolysis, acidogenesis, acetogenesis, and methanogenesis (Haandel, 2007).

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Figure 1: Anaerobic Digestion Process

Hydrolysis is the first step of the anaerobic digestion process. The process of

hydrolysis breaks down fats, proteins, and carbohydrates present in the feedstock

into sugars, fatty acids, and amino acids. The chemical reaction of this process is

shown below as Equation 2. In this reaction the carbohydrate molecule combines

with water to create hydrogen and glucose.

Next the sugars, fatty acids and amino acids are broken down further by

acidogenesis into carbonic acids, alcohols, hydrogen, carbon dioxide, and ammonia.

The equations below show the chemical reactions of the acidogenesis process. In

Equation 3, the glucose is broken down into and carbon dioxide and ethanol.

Propionic acid and water are formed from glucose hydrogen in Equation 4 and in

Equation 5 acetic acid is formed from glucose.

Acetogenesis has two types of bacteria that are involved in the process. The firsts,

called obligate anaerobes, break down the carbonic acids and alcohols to produce

acetate, hydrogen, and carbon dioxide. The second, homoacetogens, combine

hydrogen and carbon dioxide to create acetate.

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The last step of anaerobic digestion is methanogenesis. This bacteria from this

process consume the acetate, hydrogen, and carbon dioxide to produce methane.

Methanogenesis can be considered the most important step in anaerobic digestion

for multiple reasons. First is that the consumption of acetate by the methanogens

prevents acetic acid from causing a decrease in pH, thus preventing the depletion of

bacteria due to acidity (Boundless, 2014). Methane production also results from the

methanogenesis stage. Methane is an energy source that has economic value. In the

state of Virginia, the average price of natural gas for residential use is 11.68 USD per

1000 ft3 (EIA, 2014). It is this byproduct that makes anaerobic digestion

economically feasible and why it is used industrially.

Applications

Anaerobic digestion can be used to reduce waste, provide fertilizer, and generate

biogas. The methane produced may then be used for cooking fuel, generation of

electricity, or purification and grid injection. The waste reduction potential is

significant because anaerobic digestion may reduce waste by a maximum of 30% by

mass (Gerard, 2007). The produced biogas can be separated so that 60 - 99%

methane remains and can be used in a similar manner to natural gas if it is filtered

to at least 95% percent methane (Harrison, 1996).

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Feedstock

The feedstock or waste input into the reactor needs to be organic. Different

feedstock may require different adjustment of optimization parameters in order to

optimally produce biogas. The main areas of feedstock types are animal manure,

sewage, plant matter, and food waste. The advantages of using manure, sewage, and

food waste is that the feedstock is cheap and is often available year round. This

process also disposes of the material. The disadvantage of using manure or sewage

is that they often require treatment and produce less biogas than using plant matter

or food waste feedstock. The advantage of using plant matter is that you can grow

and use the plant that has a high biogas production potential. The disadvantage is

that you cannot often grow this crop year round (AgSTAR, 2014).

Products

The products of anaerobic digestion are biogas, the effluent, and heat. Biogas is

primarily made up of methane and carbon dioxide. Other gases that may be

produced in the process are nitrogen, hydrogen sulfide, ammonia and water vapor.

The concentration of these gases may depend upon the feedstock used (AgSTAR,

2014). Methane gas usually consists of 55 - 70% of the biogas and carbon dioxide

usually consists of 30 - 45% of biogas by volume (Martin, 2007) (Boundless, 2014).

There is usually less than 5% nitrogen in biogas and less than 1% hydrogen sulfide

and ammonia in biogas by volume(Martin, 2007)(Boundless, 2014).

The effluent is the solid and liquid component that is left over after the digestion

process. This includes all feedstock material that has not completely digested

undigested materials like lignin and cellulose, and water. The digestate can be used

as fertilizer because it improves soil moisture retention and is high in nutrients like

nitrogen, phosphorus, and potassium (Balasubramanian, 1992).

Most of the nitrogen in the effluent is in the form of ammonium. Ammonium is

generated by the breakdown of proteins in the feedstock. When reactor effluent is

applied as fertilizer, it needs to be incorporated into the soil in order to prevent the

ammonium from being released from the soil as ammonia. When incorporated,

microorganisms can convert the ammonia to nitrite, which is then rapidly converted

to nitrate, the nitrogen form most readily taken up by plants. Anaerobic bacteria do

not consume phosphorus or nitrogen in the feedstock, but the concentration of

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these nutrients increases because carbon, oxygen, and hydrogen are released as

biogas.

Anaerobic digestion has many positive impacts on the environment. This process

can reduce organic wastes, control odors, and reduce pathogens (Balasubramanian,

1992). Capturing biogas as opposed to it being released into the atmosphere from

landfills reduces methane emissions. Methane is a greenhouse gas that has a global

warming potential of 21. This means that over 100 years its impact on global

warming is 21 times greater than that of carbon dioxide (EPA, 2014). The methane

in the biogas that is produced can also replace fossil fuels since natural gas is 95-

98% methane (Hamburg, 1998)(Harrison, 1996). At JMU, this could replace the

cooking gas used in the dining halls and the fuel for the steam power plant on

campus. This process also diverts food waste from going to the landfill, which is

another positive environmental impact.

Optimization Parameters

Maintenance of the system pH in the proper range is required for anaerobic

digestion. The generally accepted values are in the neutral range, between 6.5 and

7.6, because of the sensitivity of the methanogens. A pH range of 4.0-8.5 is

acceptable for the continuation of activity for hydrolysis, acidogenesis, and

acetogenesis. The anaerobic digestion requires the joint work of several groups of

microorganisms, from which methanogens are the most sensitive to low pH. Unless

the system contains enough buffer capacity (alkalinity), the pH may drop below

optimal levels because the acidogenesis and acetogenesis steps of anaerobic

digestion produce acids. The biogas production may decrease until none is

produced is the pH drops too low for the methanogens to survive. Another

important thing to note about pH is the organisms produce alkalinity as they

consume protein-rich food waste.

Temperature can influence the rate of bacterial action as well as the quantity

of moisture in the biogas, as moisture content increases exponentially with

temperature. Temperature fluctuations can be very harmful to the digestion

process, especially to the methanogenic bacteria (Banks, 2006). Typically,

mesophilic bacteria can withstand temperature fluctuations of three degrees Celsius

(Banks, 2006). This is why it is important to keep the temperature constant

throughout the digestion process. Determining what range of temperature will be

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used is of paramount importance as mesophilic and thermophilic ranges offer many

advantages and disadvantages. The mesophilic temperature range is 20-45 degrees

Celsius, while thermophilic temperature range is 45 to 120 degrees Celsius

(Hazeltine, 2003). Reactors with mesophilic conditions generally have higher

stability, less odor, and less energy. Reactors with thermophilic conditions have

increased solids reduction, higher growth rate of organisms, and reduced retention

times. There are benefits to both temperature ranges, but the stability offered

by mesophilic bacteria is a large reason for its worldwide use. Operation within the

mesophilic range is stable, but straying outside this range results in the rate of

digestion greatly decreasing. Methanogenic diversity is often low among plants

operating at thermophilic temperatures, making these operations even more

sensitive to changes in temperature and other optimization parameters. The

difference in energy requirements also plays a large role, as the amount of energy

required to maintain a thermophilic environment is much higher than maintaining

mesophilic conditions.

The amount of water present with the organic waste also affects the anaerobic

digestion process. Water is needed and produced in some of the reactions shown in

the acidogenesis, acetogenesis, and methanogenesis chemical equations. It also

plays an important role in reducing air pockets and bubbles in the feedstock that

may contain oxygen, which is harmful to the anaerobic digestion process. Although

it is important, too much water can lower the biogas production potential because

feedstock is available at a time for digestion. Typical ranges of the solid content by

weight is 50% to 5% (Nge, 1992)

Anaerobic Digestion Systems Classification

Anaerobic digestion systems are typically classified by a number of different

attributes. These attributes are temperature, method of loading, orientation of the

digester, water content, and number of digesters. The temperature for the digester

can be either mesophilic or thermophilic as described in the optimization

parameters section above. The anaerobic digestion process can be a continuous or

batch system. The continuous system produces a continuous flow of biogas and

consumes a continuous amount of waste. The process is complicated because waste

that has already been digested must be separated from the undigested waste in

order to make room for new waste to be put into the system. This also requires a

constant feed rate to ensure that one type of bacteria does not dominate the system

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(Hazeltine, 2003). The batch process involves putting the waste into the reactor and

waiting until waste is digested. Then the system is emptied and waste is added. This

process produces an uneven amount of biogas over time because it takes at least 5

days (Hazeltine, 2003) for the process to begin producing biogas (AgSTAR, 2014).

The system can be oriented vertically or horizontally. The system can be a wet or

dry system. The system can have one digester of multiple.

4 SYSTEM REQUIREMENTS AND ANALYSIS

The system must comply with the Fuels Safety Program issued by the Technical

Standards and Safety Authority (TSSA), stating that the gas produced must have a

composition that is 50% methane in order for it to be considered biogas. JMU dining

services and local farmers serve as potential end users of the system outputs and

require that their needs be met in order for them to effectively utilize these outputs.

In order for farmers to use the effluent as fertilizer it must contain potassium,

nitrogen, and phosphorus, basic plant nutrients that promote plant growth (EPA,

2012). If it were the case that dining services made use of the gas produced, it would

need to meet the TSSA standard previously noted in order for this to happen.

4.1 Social Requirements

It is required that the odor generated from the anaerobic digestion process is

minimized in order to sustain the current quality of campus life. Odor is quantified

by hydrogen sulfide content in the biogas yielded from the process, due to the fact

that hydrogen sulfide has a pungent stench. Thus, hydrogen sulfide composition in

the biogas must be minimized via purification of the biogas to the best of the project

team’s ability given the current budget, time, and feasibility constraints in order to

sustain the current quality of campus life. The project team altered parameters of

the digestion system including inputs of the feedstock and the design of the overall

system. Implementation of a filter that captures hydrogen sulfide and other gas

products of anaerobic digestion accomplish the goal of trapping odor before

methane is separated, compressed, and stored.

4.2 Environmental Requirements

It is required of the reactor to remove the potential pollution to the environment

caused by sending the food waste to a landfill. A requirement of the reactor is that it

must remove more potential pollution than it creates as it is made. The reactor has

met this requirement and is considered environmentally sustainable.

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4.3 Technical Requirements

It is required that the reactor be compatible with all sensors and accessories that

will be implemented by the project team to monitor and measure both the feedstock

and biogas. The reactor must have a means which the project team can access the

feedstock and biogas during anytime of the digestion process. The reactor must also

have a minimum processing capacity of 55 gallons in order to process one meal’s

worth of waste from E-hall as arbitrarily defined by the project team. Another

requirement of the reactor is that it must be completely airtight. If the reactor is not

airtight, the product will have less (if any) methane, therefore making it less

efficient.

Biogas that is obtained from the system must have a composition of at least 50%

methane as defined by the TSSA Biogas Approval Code. The calculated amount of

methane to be received is 1.09*10-4 kg/day. End users of yielded methane such as

JMU dining services or customers require that the gas contains enough methane

content such that it can be effectively burned in generating heat.

4.4 Economic Requirements

All components of the anaerobic digestion process did not exceed the budget

allocated by the James Madison University school of Engineering. The project team

treasurer Ciara Middleton kept record of all team spending and monitored the

team’s budget status to ensure the anaerobic digestion system surpassed this

economic requirement. A requirement for the reactor is that it must produce

enough methane in order to counterbalance the price of the reactor. In other words,

it must produce an amount of methane that has the selling value of the reactor itself.

4.5 System Analysis

Process Model

Process models can clarify customer expectations and create a greater

understanding of user interaction. The process model can lead to an iteration of

function models.

The first three steps to create a process model are identifying the process, creating a

box model, and creating an event chain. In the first step of creating a process model

for the Anaerobic Digestion Capstone Project, three processes were identified as the

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actual anaerobic digestion, the methane storage, and gas separation. These

processes have boundaries to indicate what they include called system boundary.

The next step is creating a box model for each of these processes.

The first process is the anaerobic digestion system with a system boundary of

everything inside of the reactor. Initially the reactor will be a container with just air

in it until the inputs are placed inside and the container is sealed. This is the

boundary that is chosen because the team wants to analyze the inputs and outputs

of the reactor itself. The inputs would be food waste from E Hall, a small amount of

manure (to jump start the anaerobic bacteria population), and ideal conditions (Low

to no oxygen present, neutral pH, and nothing that may potentially harm bacteria).

The outputs of the system are biogas (consisting of methane, hydrogen sulfide, and

carbon dioxide) and the leftover material that was not completely digested called

the effluent. The inputs and outputs along with the known corresponding values are

shown in Table 1 below. The box diagram of this system can be seen in Appendix 1.

Table 1: Anaerobic Digestion System Inputs and Outputs

Each of these outputs have unknown values for them because the amount of manure

is unknown. Testing is presently being conducted to find a value for the amount of

manure to be used. For the anaerobic digestion system, the volume of the reactor

and the ambient temperature are the controls. The variable is the concentration of

manure to food waste in the mixture. The measured value is the amount of methane

and carbon dioxide is produced given different concentrations of manure to food

waste.

The next process is the methane storage system that has a system boundary of the

route that methane gas takes to get from the reactor to the storage area and the

storage area itself. This would include pipes that transport methane or biogas

(consisting of methane, carbon dioxide, and hydrogen sulfide), the gas separation

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system, and gas storage tanks. The inputs would be the biogas from the reactor,

electricity to power the movement of the gas or the gas separation process, the

signal input from the methane sensors to indicated the methane content, and the

signal input from the valves on the pipes being open or closed. The outputs of the

system are the carbon dioxide and hydrogen sulfide that is separated from the

methane and discarded, the signal from the methane sensors to indicate the

methane content of the stored gas, and the amount of gas pressure accumulated in

the storage tanks. The inputs and outputs along with the known corresponding

values are shown in Table 2 below. The box diagram of this system can be seen in

Appendix 1.

Table 2: Anaerobic Digestion System Inputs and Outputs

None of these values are known because the value of manure to be used is unknown.

Once the value for the manure is discovered, each of these values will be able to be

solved for. For the methane storage system, the control is the volume of the tank. A

constraint is the pressure that methane is able to be compressed at. The measured

value to look for in this process is the quality of the methane content.

The last process is the gas separation system with a system boundary. The system

boundary for this process is a more specific section of the methane storage system.

It consists of the equipment used to separate the methane from the rest of the gases.

Examples of the separating process include water washing, pressure swing

adsorption, selexol adsorption, or amine gas treating equipment or possibly some

combination of more than one. The inputs of the system are the biogas mixture

(methane, carbon dioxide, hydrogen sulfide, and a small amount of water vapor),

electricity to power the system, and biogas. The outputs are methane, hydrogen

sulfide, water, carbon dioxide, heat, and a light to indicate if the system is working.

The inputs and outputs along with the known corresponding values are shown in

Table 3 below. The box diagram of this system can be seen in Appendix 1.

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Table 3: Gas Separation System Inputs and Outputs

None of these values are known because the value of manure to be used is unknown.

Once the value for the manure is discovered, each of these values will be able to be

solved for. The control for this system is the material of the filtration element. The

constraints of the system are the amount of gases that already exist but need to be

filtered out. The variables are the amount of each filtration element that is put in the

filter and the measures taken are the amounts of waste gases after filtration

The next step to create a process model is to break down each process into event

chains. The process that is broken down in Figure 2 is the anaerobic digestion

process shown which is explained above in the first box model. This process was

chosen because it is important to understand how to produce biogas before

anything can be done with the biogas. The food waste entering of the system will

consist of carbohydrates, fats, and proteins so they are listed because they are more

descriptive than saying “food waste”. The events that anaerobic digestion can be

broken into are hydrolysis, acidogenesis, acetogenesis, and methanogenesis.

Shown in Equation 2 in the literature review, hydrolysis takes fats, proteins,

carbohydrates, and heat in and breaks them down into sugars fatty acid, amino

acids, and heat. This event starts on approximately day one and finishes

approximately on day 14.

Acidogenesis uses the inputs sugars, fatty acids, amino acids, and heat from

hydrolysis and breaks down these compounds further into many other compounds

and starts on approximately day two and finishes approximately on day sixteen.

Lignin and cellulose are outputs that are not needed for the next events and are part

of the digestate that is removed at the end of the digestion process.

The outputs from acidogenesis of carbonic acid, alcohols, hydrogen, carbon dioxide,

ammonia, and heat are all also inputs for acetogenesis. Acetogenesis uses these

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compounds to produce outputs of hydrogen, acetic acid, carbon dioxide, and heat.

This event starts approximately day four and ends approximately day 21.

The last event in this process is methanogenesis, which has inputs of hydrogen,

acetic acid, carbon dioxide, and heat from acetogenesis and creates the outputs of

methane, carbon dioxide, ammoniums, phosphates, and heat. This process starts on

approximately day seven and finishes approximately day twenty eight. The

ammoniums and phosphates are listed underneath instead of on the side because

they are included in the digestate, which may be used as fertilizer.

Figure 2: Process model for digestion process

Functional Model

Functional models can be very useful when used in the design process. They can

help describe exactly what a concept must do. A functional model consists of verb

noun pairs that describe what happens. This is different from the processes model

because it does not include time and describes what happens as opposed to how

thing happen.

There are a few steps to complete the functional model. First, identify a function and

describe it with a box model. Next break down this function into events and create a

chain of events that need to happen to achieve the function. Then decompose each

event and verify this function model with the customer.

The function that will be analyzed is the digest waste. The function of this process is

to convert food waste into methane. The system boundary is the digestion system.

This system is defined as everything inside of the reactor. Initially the reactor will be

a container with just air in it until the inputs are placed inside and the container is

sealed. The box model for this system is shown below as Figure 3.

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Figure 3: Box model for waste digestion system

The next step to create a functional model is to break down each process into event

chains. The function that is broken down in the figure below is the digest waste

function, which is explained above in the first box model. This function was chosen

because it is important to understand how to produce biogas before anything can be

done with the biogas. The food waste entering of the system will consist of

carbohydrates, fats, and proteins so they are listed because they are more

descriptive than saying “food waste”. The functions that digest waste can be broken

into are break down organic polymers, break down organic monomers, produce

acetic acid, and produce biogas.

The break down organic polymers function takes fats, proteins, carbohydrates, and

heat in and breaks them down into sugars fatty acid, amino acids, and heat.

The break down organic monomers function uses the inputs sugars, fatty acids,

amino acids, and heat from hydrolysis and breaks down these compounds further

into many other compounds. Lignin and cellulose are outputs that are not needed

for the next events and are part of the digestate that is removed at the end of the

digestion process.

The outputs from the break down organic monomers function of carbonic acid,

alcohols, hydrogen, carbon dioxide, ammonia, and heat are all also inputs for the

produce acetic acid function. The produce acetic acid function uses these

compounds to produce outputs of hydrogen, acetic acid, carbon dioxide, and heat.

The last event in this functional model is produce biogas, which has inputs of

hydrogen, acetic acid, carbon dioxide, and heat from the produce acetic acid function

and creates the outputs of methane, carbon dioxide, ammoniums, phosphates, and

21

heat. The ammoniums and phosphates are listed underneath instead of on the side

because they are included in the digestate, which may be used as fertilizer.

Figure 4: Anaerobic digestion function chain

The functions can be broken down even further, decomposing the events into a

more specific chain of functions. Below is a figure of the break down organic

polymers function broken down further into function statements?

Figure 5: The break down organic polymers function broken down further into

function statements

22

A function means tree is similar to a functional model because it helps the designer

understand the system better. Function means trees are used in design to generate

solutions to functions in a hierarchic manner. It associates functions with possible

solutions and is very different from a morphological matrix. Function means trees

get more creative the more branches that are added to them. They are very useful

for making connections to similar ideas and functions that previously could not be

determined. The function means tree shown below is for the reduce waste function.

The trapezoids are solutions while the rectangles are functions.

Figure 6: Functional model of hydrolysis

Feedstock Testing Data

Testing was conducted to characterize feedstock that would be implemented in the

digestion system. Moisture content, PH, and ORP were the parameters chosen to

characterize the system. Each parameter was measured for four samples of the

slurry output from East Campus Dining Hall during both lunch and dinner hours for

a total of eight samples each weekday. Samples were retested for the same

parameters after one week. The pH and ORP values for a day’s batch of samples

taken during the same period, either noon or evening, were averaged to obtain one

value for the noon and evening for that day. The pH and ORP results from the first

series of feedstock characterization tests are shown below as Figure 7 and 8

respectively.

23

Figure 7: Average pH of feedstock for noon and evening E-hall hours each weekday

Figure 8: Average ORP of feedstock for noon and evening E-hall hours each weekday

Sample raw data is provided in Appendix 2.

24

The average moisture content of all preliminary feedstock samples was measured to

be 82% saturation with a standard error of 4.18%.

The pH and ORP results that were measured a week later were averaged within

each sample batch similar to the preliminary results. The results are summarized

below as Figures 9 and 10 respectively.

Figure 9: Change in average pH of feedstock for noon and evening E-hall hours each

weekday

25

-

Figure 10: Change in average ORP of feedstock for noon and evening E-hall hours each

weekday

The data indicates that the digestion process is progressing as normal with the

decrease in pH, but the ORP values increase, which indicate that the ability for

oxygen to bond with present compounds that are unfavorable to methanogen are is

high as a result of the prevalence of these compounds. The conditions of the

feedstock are allowing the acetogen to thrive and produce acetic acid, but are harsh

on the methanogen which limit their ability to produce methane as the acetic acid

present is limiting the metabolism of the methanogen. The conditions can be made

more favorable for methanogen by adding a buffer such as sodium bicarbonate to

negate some of the effects of the acetic acid produced by the acetogen. Sodium

bicarbonate is an ingredient of baking soda and thus can be added to the system as a

buffer.

5 CONCEPTUAL DESIGN AND ANALYSIS

During the conceptual design phase of the design process, concepts are generated

and evaluated, and one is selected to proceed into the preliminary design phase.

Conceptual design is encompassed by three sections: Concept Generation, Concept

Evaluation, and Concept Selection.

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5.1 Concept Generation

The concept generation phase begins with research on relevant existing systems

that solve similar problems that the capstone team is trying to solve. The purpose of

doing this is to see which solutions could pertain to this project and to see if it is

ideal to implement them. The next phase of concept generation is formulating a

morphological matrix that shows these possible solutions to a number of specific

design functions. The morphological matrix specific to our anaerobic digestion

process was created with ten functions and can be seen in Appendix 3. This matrix

was populated by possible solutions from looking at patents and engineering

catalogs. Two, of each solution, were from patents and the other two were from

catalogs. This was done by looking for key words from the function in the patent

databases and engineering catalogs. When a solution was found a picture was added

to the matrix to provide a visual for the solution.

Different concepts were able to be generated using several different methods. The

rigid reactor concept is the concept that has already been built as a prototype and it

has a rigid reactor tank. The detachable gas tank and the gas tank within the reactor

concepts were able to be generated using the TRIZ process. TRIZ is a concept

generation process that looks at patterns of past inventions in order to find a similar

solution principal that may help produce a new concept. The thought process

behind TRIZ is that problems and solutions are repeated across all disciplines, and

that patterns of technical evolution can be found in these problems and solutions,

and the innovations used information from outside the discipline in which they

were created. There are four steps to the TRIZ process: 1) Determine the conflicts or

contradictions in the technical system, 2) Formulate the conflicts in terms of

generalized characteristics of technical systems, 3) Determine design principles

using contradiction matrix, and 4) Review and (attempt to) apply principles to

generate solutions to solve the conflict. This basically means that in TRIZ there is a

specific problem that is trying to be solved. This problem can be split up into two

contradicting goals. Then using the contradicting goals, find the typical solution

principals. Then use the solution principals to find a specific solution to the problem.

This TRIZ process was done for the detachable gas tank and the gas tank within the

reactor concepts by first identifying a technical contradiction from a list of 39

features of the project and the contradiction identified is if you maximize the

volume of the moving object, it minimizes the manufacturability of the product. The

object is moving because one of the parameters that were set for our design is the

27

reactor must be mobile. Once the contradiction was identified, the improving and

worsening conflict was then found in the contradiction matrix from the TRIZ

handout and it showed three different solutions. These solutions were

Segmentation, Pneumatic or Hydraulic Construction, and Composite Materials.

Segmentation means the reactor should be divided into independent parts. This

solution was used to make one of the concepts for design. The reactor is can be

segmented by the reactor and methane tank being separate. This will make the

reactor as a whole easier to be manufactured because they can be manufactured

separately. This solution can be seen below in Figure 11.

Figure 11: Solution Principle-Segmentation (a)

The solution of Segmentation was also used to address the technical conflict that

arises in increasing the capacity of the reactor for the second concept. A reactor has

been designed to incorporate modular parts so that it can be assembled and

disassembled to promote the volume of the moving object while maintaining

manufacture feasibility. An inner chamber can be fabricated to fit into the reactor to

collect methane gas, which is depicted in Appendix 3.

The reactors (where the bacteria digests food waste) will likely require heating to

reach the optimal biogas production temperature, however an effort is being made

not to waste energy using a heater because that will increase the net carbon

emissions of the system, thus making it not as sustainable. Using the TRIZ concept

28

generation method, the contradiction in this case would be improving temperature

and worsening loss of energy. The principal solutions to this contradiction are

rushing through, transitioning into a new dimension (i.e. moving an object in two or

three-dimensional space), transformation properties, and accelerated oxidation.

Solutions Explained

Skipping or rushing through means conducting a process or certain stages at high

speed to avoid negative consequences. Skipping or rushing through may not work

because the organisms will take time to grow which probably eliminates the ability

to speed the process significantly.

Transition into a new dimension may mean using a multi-story arrangement of

objects instead of a single-story arrangement. Alternatively, it could be something

like re-orienting the object, laying it on its side, or using another side of a given area.

Transition into a new dimension could be applied by having more than one reactor

set up next to each other to minimize heat loss.

Examples of accelerated oxidation are replace common air with oxygen-enriched

air, replace enriched air with pure oxygen, expose air to ionizing radiation, or

replace with ozone. The accelerated oxidation solution will definitely not be able to

be applied to the project because the organisms used will be anaerobic, so we will

try to not have any oxygen in the system.

The most promising solution is using transformation properties. Transformation

properties could mean change an object's physical state, change the concentration,

change of consistency, change the degree of flexibility, or change the temperature. In

this case, the reactor is heated for optimal biogas production and heat loss is

minimized by using insulation around the reactor. A sketch of this concept is shown

below in Figure 12.

29

Figure 12: Transformation property solution

The project goal is to process as much food waste as possible while also considering

the usability of the system so that it is not too difficult for others to operate. The

contradiction would be improving the amount of substance while also improving

the convenience of use. Using the TRIZ method, the principal solutions are

30

transformation properties, pneumatics or hydraulic construction, self-service, and

prior or preliminary action.

Transformation properties means changing an object's physical state, changing the

concentration, changing of consistency, changing the degree of flexibility, or

changing the temperature. A transformation property solution, to make the reactor

easier to use, would be to make the amount of food waste added a more flexible

amount. This probably would not be of much use because it may affect other factors

like amount of biogas created and there would be consistency issues.

Preliminary action can mean perform the required change of an object before it is

needed or pre-arrange objects such that they can come into action from the most

convenient place without losing time for their delivery. The preliminary action

solution is not the best solution because it would require that someone who is

trained in how to perform the preliminary action to check on the project, which

would decrease the ease of use.

The self- service and hydraulic construction solutions would probably not be very

effective alone but could be very effective if combined. Pneumatics/ hydraulic

construction mean the use of gas and liquid parts of an object instead of solid parts.

Self-service could be to make an object serve itself by performing auxiliary helpful

functions or use waste resources, energy, or substances. If these two solutions

principals were combined so that the food waste mixed with water is pumped from

the source to our design at regular intervals, the design would be effective. A sketch

of this concept is shown below in Figure 13.

Figure 13: Self-service and hydraulic construction solution

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The next two concepts were formed using the method of biomimicry. Biomimicry is

a method that uses things found in nature for inspirations in engineering products.

The first inspiration for a concept was an octopus. An octopus has 8 legs that each

contribute to feeding one mouth. Similarly, multiple reactor tanks could be hooked

up to one methane tank, providing the most “food” for the “body,” or gas tank. An

image of this concept from the inspiration of an octopus can be seen below in Figure

14.

Figure 14: Concept Inspired by Octopus

The next concept was generated using the biomimicry method. The inspiration for

this design came from the lining in the human stomach. This lining protects the rest

of the body from the stomach’s highly acidic environment. Though this isn’t

specifically a function that the anaerobic system needs to complete, the idea is still a

useful one.

In this design, the reactor is lined with a thin elastic film, with extra film left free at

the top. Once the reactor is filled, the lining is then sealed over top of it, suppressing

all air out of the system. A small tube is inserted into the center of the feedstock to

32

allow the biogas to escape, so the lining with fit snug around this to continue

keeping air out of the system. This is important because anaerobic digestion is a

process that takes place in the absence of air. Having the lining will keep the

reaction from turning into an aerobic digestion process, thus fulfilling the design

constraints. A sketch of this reactor can be found below, in Figure 15.

Figure 15: Concept Inspired by Stomach Lining

Alternative concepts that did not move past the absolute criteria matrix were left

out of this portion of the report, but can be seen in Appendix 3.

Since each of the reactors have been batch reactors, the team thought it was a good

idea to at least include one continuous reactor to compete with the batch reactors in

the concept evaluation phase. We know that a system that has a large volume as

opposed to a system that has a lower volume produces more biogas volume per

waste (Hazeltine, 2003); therefore, the continuous system will have a large volume.

Along with having a larger volume, since the system is continuous, it must have a

continuous input and output. Since the food waste requires up to 15 days to fully

digest (Hazeltine, 2003), it, in combination with manure, will be “continuously” fed

in 55 gal/day with nothing coming out of the system for 15 days. On the 16th day,

the effluent collection valve will be opened for a release of 55 gallons minus the

volume of gas received per day, putting the reactor in equilibrium. This continuous

33

reactor also includes three critical elements for retrieving clean methane for use.

These three elements are a filter, compressor, and storage container. The filter is

used to filter the biogas in order to filter out everything but the useful methane. The

compressor is used to compress the received methane and put it in the storage

container. This continuous system can be seen below in Figure 16.

Figure 16: Continuous batch system design

5.2 Concept Evaluation

These five concepts, along with those thrown out because failing this evaluation,

were then evaluated against each other using absolute criteria. Absolute criteria

were formed from system requirements that the system must perform. The system

requirements chosen to receive the criteria from are: produce a clean biogas,

produce fertilizer, dispense gas, and to reduce greenhouse emissions. The absolute

criteria formed from these requirements are: contain the biogas produced, produce

methane, and dispense gas at a safe rate. These absolute criteria were then put into

a matrix against the different concepts in order to receive a go/no-go solution to if

the concept should move on in the concept evaluation phase. This matrix can be

seen below in Table 4.

34

Table 4: Absolute Criteria Matrix

Once each of the concepts that did not meet the absolute criteria need was thrown

out, the remaining concepts could be evaluated against the relative criteria. The

relative criteria generated include: digest waste, waste decomposes into fertilizer,

and biogas contains at least 50% methane. Digest waste is relative because there are

different degrees of digestion and different stages of the process. Food waste can be

partially digested and produce methane without being completely digested. Due to

this, waste decomposing into fertilizer is also relative. The food waste may produce

methane without all of it going to fertilizer. The biogas being at least 50% methane

is relative because it can have a composition above 50% methane and pass the

system requirement. An additional relative criteria added to the list from last week

is the removal of fertilizer from the digestion tank. It is relative because all of the

fertilizer does not have to be removed from the reactor to produce methane.

Another relative criteria added to the list from last week is the portability of biogas

after digestion. It is relative because each of the different concepts has a different

portability of the biogas chamber.

Each of the remaining concepts was put into a decision matrix to be subject to each

of the relative criteria. The digest waste criteria had a weight of 25% because it is

the main purpose of our capstone product. The purpose of the project is to reduce

waste via anaerobic digestion to obtain biogas. The waste transforms to fertilizer

criteria had a weight of 18% because we would like the digested food waste to be

useful after it goes through the digestion process. The composition of biogas must

be at least 50% methane criteria had a weight of 24% because it is the second most

important part of our project. Once the food waste is digested, it must produce

35

useful biogas. In order for it to be useful, it must contain at least 50% methane. The

removal of fertilizer criteria had a weight of 5% because it is the least important

relative criteria. It is the least important because digestion will take place even if the

digested waste is not removed from the reactor tank. The portability of biogas

criteria had a weight of 10% because it is important for the gas to be removable

because we would like the gas to be easily transportable in order for it to be used by

potential customers in diverse locations. The ease of implementing the design was

assigned a weight of 18% because it is important that it is possible to actually be

able to implement the design that is formed. This decision matrix along with each of

the criteria and their respective weights can be seen below in Table 5.

Table 5: Decision Matrix

For further evaluation, the concepts were ranked using criteria derived from

economic and environmental impacts that could occur over the lifecycle of the

reactor. Three Economic criteria were formed from these impacts. The first of these

criteria is the cost of the raw materials of the entire tank and its parts including the

cost of the materials, labor, and transportation. The second criterion is the cost of

the manufacturing of the entire tank and each of the parts. The third is the potential

money to be saved with the amount of biogas produced. Along with these economic

criteria, four environmental criteria were derived from the environmental impacts.

The first of these environmental criteria is reducing the drive time to landfill for

waste in order to reduce CO2 emissions. The second criterion is the recyclability of

the reactor in order to keep it from going to the landfill. The third and fourth criteria

are: reducing the methane released into the atmosphere from the breakdown of

food waste in a landfill and reducing the amount of food waste going to the landfill.

Reducing the amount of any material going to a landfill is always a positive

environmental impact.

36

Each of these concepts was put into a decision matrix to be subject to each of the

relative criteria. The cost of the material, labor, and transportation of the raw

materials, along with the cost of manufacturing and the money saved by the gas

produced each were set at 15% because the team wanted the economic criteria to

have approximately half of the weight and each of these criteria are equal. The

environmental criterion of reducing the drive time to prevent CO2 emissions was

given a weight of 5% because it is the least important of all of the criteria. The

criterion of recyclability was given a weight of 25% because the most negative

environmental impact it will have is if none of it is recyclable. The criteria of

reducing the amount of methane released into the atmosphere from the organic

waste being sent to the landfill was given a weight of 15% because it was slightly

more important than the criteria of reducing the amount of waste going to the

landfill, which was given a weight of 10%. Each of these criteria and each of the

concepts were put into a decision matrix to evaluate the concepts further to help

decide which the best concept to go with is. This decision matrix can be seen below

in Table 6.

Table 6: Decision Matrix-Environmental and Economic Criteria

5.3 Concept Selection

Once each of the criteria was put into the decision matrix, they were able to be

ranked in order from the best concept to the poorest. These rank ordered concepts

from the first decision matrix with each of the relative criteria can be seen below in

Table 7.

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Table 7: Rank Ordered Concepts from Relative Criteria Decision Matrix

Once each of the economic and environmental criteria was put into the decision

matrix, they were ranked in order from the best concept to the poorest based on

their weighted scores. These rank ordered concepts can be seen below in Table 8.

Table 8: Rank Ordered Concepts Environmental and Economic Criteria

Although these two methods rank the different concepts in a legitimate manner,

there is a more precise way to rate the concepts using the relative criteria of digest

waste, waste decomposition, ease of extracting fertilizer, methane concentration of

biogas, and portability, called the Analytical Hierarchy Process, or AHP. Once the

AHP method was applied, the concepts received scores and were then rank ordered,

and can be seen below in Table 9.

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Table 9: AHP Scores with Corresponding Concepts and Scores

Once each of the concept evaluation methods were applied, it is clear that the top

scoring concept from each of the evaluation methods is the continuous reactor.

Since the continuous reactor scored highest in each evaluation test, it is the concept

that the project team decided to move forward with.

6 PRELIMINARY DESIGN AND ANALYSIS

The preliminary design phase encompasses a model of the kinetics of the system

and was a useful tool in determining the specific dimensions of the system. These

dimensions were calculated using the equations outlined below, as well as

information from the Conceptual Analysis section, along with the previously

specified optimization parameters. Included in the dimensional analysis were all

connection points (sub-component inlets and outlets) throughout the system.

Understanding the governing equations of the process is a crucial aspect of refining

the design. The addition of microbes to encourage digestion means that the process

taking place is biochemical in nature. This being the case, kinetics equations can be

used to understand the behavior of the reaction that will occur. In order for these

equations to be utilized, the specific growth rate of the bacteria, μ, was found to be

0.8 ± 0.2/day (Pollard, 2006). The model of the kinetics of this system is outlined

below as described by Markowski et al.

(Eq. 13)

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Equation 13 represents the rate of change in biomass (or bacteria) with respect to

time, where X=biomass concentration.

(Eq. 14)

Using Equation 14, the rate of change in product (or biogas) with respect to time as

calculated, where .

(Eq. 15)

Finally, in Equation 15, the amount of biogas that will be produced per day was

calculated using the intended reactor volume of 500 gal, or 1.89m3.

(Eq. 16)

(Eq. 17)

The rate of change in substrate (or feedstock) with respect to time was also

calculated as shown in Equations 16 and 17, where .

The EPA P3 guidelines have relevant information to address when doing an analysis

of the project. From the EPA P3 guidelines in Appendix 4, the statutory authority

40

governing this project is the SWDA: Solid Waste Disposal Act. This is the statutory

authority because the project removes solid waste from E-hall and is placed in a

small scale, low technology solid waste management system and forming a useable

form of energy. According to these guidelines, this project falls in the research area

of Biofuels and Waste to Energy because the reactor addresses the environmental

implications of these topics.

Volume, an indicator type named in the resource flow indicators category of the

Sustainability Indicators handout previously issued, has an effect on greenhouse gas

emissions on a community and national scale. By digesting 500 gallons of waste,

1.09*10-4 kg of biogas is produced per day. Therefore, over the retention time of 21

days, the amount of biogas emitted from landfills will be reduced by 2.29*10-3 kg of

biogas. Based on these results, it is implied that greenhouse gas emissions will be

reduced by the total amount of gas this system produces per retention period. This

falls in line with the objective of the project; reducing the amount of food waste sent

to landfills, therefore reducing greenhouse gas emissions.

7 TESTING AND REFINEMENT

Comparative biogas production testing was conducted in order to attain a ratio of

manure to organic food waste in volume that results in maximum pressure of a

digester prototype. The maximum pressure from the digester prototype translates

to biogas production, and therefore, this test shows what concentration of manure is

needed in the recipe for optimal biogas production. The independent variable

measured is the ratio of manure to food waste, which impacts the dependent

variable of gas production that was measured using a manometer. The variables

measured can be seen in Table 10 below.

Table 10: Testing variables

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The testing took place in HHS 1027 lab under a fume hood where the ambient

temperature is roughly 21°C and approximately 12.5 ft2 of area under the fume

hood. These are the conditions of the experiment.

Each prototype is a five gallon bucket, having a depth of 13 inches and a diameter of

12 inches, giving a volume of 1470 in3, which is a control. Each of these prototypes

have lines marked at each half inch on the side of them, making them like graduated

cylinder. There is a 1” PVC ball valve on the lid that connects to a manometer used to

attain a pressure reading once the digester has been sitting for an extended period

of time.

Food waste and manure are hauled by hand to HHS 1027. Each of the digesters is

filled with food waste first to ensure the digesters are mixed well. The first is filled

with 1 inch (113.1 in3), the second with 2 inches (226.2 in3), and so on up to the fifth

digester. The manure is then placed into each digester, bringing the total content of

each digester to 6 inches (678.6 in3). After the manure is placed in each of the

digesters, a mixing tool is used to stir the contents until it is well mixed. Each of the

digesters is then filled with 6 inches (678.6 in3) of water and each have an equal

volume of 1357.2 in3. Once each of these digesters had water placed in them, the lids

were securely placed on top, making a seal, then labeled and placed under the fume

hood. When a week of time goes by, it is time to conduct the first pressure test. The

digesters are removed from the fume hood and placed in order from least to

greatest for ease of recording measurements.

A manometer with a 1” PVC connector and clear tubing was constructed in order to

measure pressures in the digesters. The cost of the manometer used to measure the

pressure is the cost of two PVC elbows, 6 inches of PVC, and a foot of clear tubing,

which costs $6.54. After connecting the manometer to the digester, a line is marked

on the manometer where the meniscus is originally. Once marked, the valve is

opened, which moves the height of the water in the manometer and a line is marked

at the final height. This height changed can be used to calculate the gage pressure

with respect to atmospheric using Equation 18 below.

P=ρgh (Eq. 18 )

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This measurement procedure is completed on each of the digesters, and once this

test is complete, the digesters are placed back into the fume hood. This

measurement is taken 2 more times, therefore resulting in recordings for a three

week retention time where measurements were taken on day 7, 14, and 21. This

experiment is conducted 3 times due to a full test requiring 21 days to complete and

a lack of time to complete more.

In the comparative biogas production experiment, the readings on the manometer

were taken in inches. That value was converted to meters and a corresponding

pressure was able to be found from that value compared to atmospheric using

Equation 18. Below are tables of the results gathered from each of the trials of the

experiment, including the concentration of manure and the gage pressure after 7,

14, and 21 days and uncertainty of each measurement. Table 11 represents trial 1,

Table 12 represents trial 2, and Table 13 represents trial 3.

Table 11: Trial 1 Comparative Pressure Test

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Table 12: Trial 2 Comparative Pressure Test

Table 13: Trial 3 Comparative Pressure Test

In this test, it is assumed that all of the gage pressure present is biogas. It can be

seen that after a retention time of 14 days, which is closest to the researched

retention time of 15 days, in both trials, the digester prototype with 5 inches of

manure and 1 inch of food waste has the most pressure. However, at the end of 21

days, in both trials, the prototype digester with 2 inches of manure and 4 inches of

food waste has the most pressure. The results of the average pressure in each of the

digesters was placed into a bar graph, with error bars showing one standard

deviation, or the variance, from the average for each of the testing prototypes. This

bar graph can be seen below in Figure 17.

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Figure 17: Average pressure in testing prototype after 21 days

The reason that manure is added to the food waste is because microbes exist in the

manure that consume the organic food waste and create biogas. The manure can be

seen as the microbes and the food waste can be seen as the microbe’s food. The

reason the prototype digester with five inches (565.5 in3) of manure in it had the

highest pressure recording after two weeks for both of the trials is because it had

the most microbes present, initiating the starting time for biogas production quicker

than the other digesters. However, another reading was taken on day 21 to see what

the gage pressure would be. In each of the trials, the prototype digester that had two

inches (226.2 in3) of manure overtook the prototype digester with five inches (565.5

in3) of manure in pressure production. This could be because the microbes had

more food to eat to create biogas and they just took a longer time to produce any.

This result changes the retention time of the mixture that is placed in the digester. It

is an excellent result because it shows that a recipe does not have to be mostly

manure to create a large amount of biogas, and can instead use mostly organic food

waste. It is further even more important because it is better for the digester to

require more food waste than manure because the purpose of this digester is to

reduce the food waste coming from E-hall.

There are a couple limitations and interferences associated with the testing protocol

and resource constraints. Two interferences associated with the testing protocol are

a leak in the system and the assumption that all of the pressure is usable biogas

45

(>50% methane). Air-tightness is a hard task to accomplish and this issue was

accounted for by resealing any digester if necessary. The limitation associated with

resource constraints is the limitation of time. Each test takes three weeks and

because of the space available in HHS 1027, digester size, and cost, only one test can

be run at once.

8 DETAILED DESIGN AND ANALYSIS

Reactor

The reactor is the main part of the anaerobic system where the food is digested and

biogas is created. The size of the reactor is limited to the size of the room next to the

room where the food waste exits a grinder and the size of the entrance to that room,

which has width of 49” and a height of 84”. The maximum size of the tank found that

will fit through the door is found to be a 500 gallon 45 degree cone bottom tank. The

size of the specific tank chosen to go in the room has a height of 85” and a diameter

of 48” which will easily fit in the adjacent room to the food waste grinder and also

means it would need to be turned on its side to fit through the door. The reactor

tank is made of polyethylene to insure that it will not react with the contents of the

tank. The reactor tank has an inlet on the top of the digester of 16” and has an outlet

at the bottom of the cone bottom tank of 2”. The inlet of the tank comes from the

submersible slurry pump, which pumps the mixed recipe through a 2” hose which is

connected to the 16” inlet at the top. The bottom of the reactor tank will have a PVC

ball valve with an effluent tank underneath of it where 55 gallons of the contents of

the digester, or a useful fertilizer, can be emptied into an effluent tank, and

transported to a usable location.

Filter

A filter is necessary in the design for multiple reasons. The first is to upgrade biogas

into natural gas (methane). Secondly, the filter would decrease the corrosiveness of

the biogas in order for it to be safe to pass through the compressor. The filter would

also reduce the smell and reduce amount of storage needed for the gas. In order to

accomplish all of these things, the filter would need to separate the methane from

the other gasses in biogas: Carbon dioxide, hydrogen sulfide, and ammonia (see

literature review). Iron oxide was chosen to remove hydrogen sulfide, which it

would remove by reaction (Abatzoglou and Boivin, 2009) (Siefers, 2010). Activated

carbon was chosen to remove ammonia and carbon dioxide by absorption (). These

46

components were chosen because they are readily available and inexpensive. The

filter was designed to last 365 days in order to make the operation easier.

Hydrogen sulfide reacts with iron oxide and produces water and hydrogen sulfide

according to the equations below:

4𝐻2𝑆 + 𝐹𝑒2𝑂3 → 𝐹𝑒𝑆2 + 𝐻2𝑂 + 𝐻2 (Eq. 18)

𝐻2 + 3𝐹𝑒2𝑂3 → 2𝐹𝑒𝑂4 + 𝐻2𝑂

(Eq. 19)

The amount of iron oxide necessary was then determined by using the estimation of

biogas production of the digester (in the preliminary design and analysis section),

which is 0.109 grams per day. The maximum hydrogen sulfide content of biogas was

assumed to be 500 ppm (Seifers, 2007). The efficiency of the reaction was

determined to be between 60-85% (McKinsey, 2003) so the lower efficiency value

of 60% was used. Based upon the chemical equations above, maximum sulfide

content, estimated biogas production, and efficiency of the reaction, the total

amount of iron oxide needed is 0.1629 grams. That value was then multiplied by

two, in order to cover possible errors in the assumptions made, for a final value of

0.3258 grams of iron oxide in the filter.

Activated carbon can absorb various substances because it has a large number of

small pores in each piece that capture the substance. The amount of activated

carbon needed was determined by using absorption rates of ammonia and carbon

dioxide under similar conditions. It was also assumed that the two gasses were

competing for the same pores in activated carbon in order to estimate the largest

possible load. According to Christiano (2007) the abortion rate of ammonia is 3.2mg

per gram chemically activated carbon and the ammonia concentration in biogas is

100 mg per kg of biogas. The absorption rate of carbon dioxide is 45.7 mg per gram

of activated carbon (Loong, 2007) and the concentration is 45.7 mg carbon dioxide

per kg biogas. Assuming the production of biogas is 0.109 grams per day and carbon

dioxide content is 45%, the total activated carbon needed in the filter would be

603.528 grams. This value was then multiplied by two, in order to cover possible

errors in the assumptions made, for a final value of 1207.055 grams.

47

The filter contents will be held by a 2” OD PVC pipe with filter paper in between the substances and on the top and the bottom shown in the figure below.

Figure 18: Orientation of the components in the filter

Connections

The components of the system are connected by a number of pipes. The first pipe

connects the pump to the digester. This pipe is made of 4 inch outer diameter PVC

pipe. The pipe is 4 inch diameter so that the feedstock does not clog the pipe and

PVC because it is cheap and will not corrode. The next pipe connects the digester to

the filter. This pipe is also PVC and has a 2 inch outer diameter. The last pipe is a soft

PVC pipe connecting the compressor to the gas tank. The connections are all sealed

with a glue sealant to make the airtight.

Compressor

In this system, the functions of the compressor are to assist in moving the gas

through the filter and into storage. The specifications of the compressor were based

on the daily production rate of biogas previously discussed. The low production rate

indicated that a low back-pressure compressor would be necessary to perform the

proper functions within the system. Initially, a general refrigerator-grade

compressor was chosen, as the pressure requirements are within the limits of the

system design. However, upon consultation with lab safety authorities, it was

decided that a compressor designed specifically for biogas was necessary in order to

minimize safety risks. Of the four available biogas compressor models, the Copeland

scroll compressor with model number YDB-ZW-0.8/8 was chosen based on its

power consumption of 7.5kW as compared to the 11-30kW requirements of the

other models.

48

Storage

An empty propane tank is used to store biogas for use as an energy source or retail.

A hose would be fitted to the ends of the tank and compressor that serves to create a

pressure difference to vacuum biogas from the reactor. The tank would be filled

after every retention period of 21 days until full, at which point the tank would be

disconnected from the system and replaced with a new tank. The tank has a

maximum capacity of one gallon and has an empty weight of 11 pounds. The tank is

specified as having a height of 12’’ and a diameter of 9’’.

Economic Analysis

Annual costs to operate the compressor and recipe pump were calculated using

local rates for electricity for a total annual operating cost of 1.32 USD. The loss of

monetary value in the capital investment of 2340 USD was considered as an annual

cost and was calculated using Equation 20:

F = P(1 − i)n

(Eq. 20)

where F is the futuristic value, P is the present value, i is interest at 3%, and n is the

number of years. Annual operating cost and loss in monetary value of the capital

investment together account for the total cost of the system for a given year.

The selling price for biogas was assumed to be the same value reported by the

Southern California Gas Company at 3.89 USD per MMbtu. The annual production of

biogas yielded by the system as well as the salvage value of the compressor and

slurry pump was considered to be the total benefit of the system for a given year.

The salvage values were calculated using Equation 20 to determine the difference in

value of the initial investment and value in salvage. Figure 19 depicts the yearly

breakdown of total cost and total benefit of the system for the duration of its useful

life of 5 years.

49

Figure 19. Total cost and total benefit of the system during its useful life.

The annual benefit of the system is nearly entirely due to the value gained in salvage

since the system produces 0.01 USD of biogas according to the Southern California

Gas Company. The total costs overtake the total benefit each year. A projection of

total cost and total benefit was carried beyond the useful life of the system up to 25

years as shown in Figure 20:

Figure 20: Total cost and total benefit beyond useful life

50

The system will not break even and is not economically sustainable. Annual benefits

would have to increase to reach a break-even point. This would result if more biogas

was produced by the system, which requires a larger reactor to process more food

waste.

9 PROJECT MANAGEMENT PLAN

9.1 Team Management

The student team consists of Kyle Groves, Ciara Middleton, Cairo Sherrell, and Will

Steinhilber. Kyle Groves is from Harrisonburg, Virginia and is the machinist/test

lead of the project team. The machinist/test lead heads all tests that are conducted

for modeling and analysis of the anaerobic digestion system. He also constructs all

physical prototypes. This semester entails Kyle to conduct pH and ORP testing of

manure samples from local farms that will be added as raw material with the

feedstock, conduct tests to comparatively assess the outcomes of inoculating

feedstock with variable amounts of manure, and creating a bill of materials for

prototyping the anaerobic digestion system. Ciara Middleton; from Frederick,

Maryland, has the role of treasurer and recorder. She keeps record of all team

finances, records, and documentation either manually or electronically. Ciara

monitors the team budget while conducting all purchase transactions. As project

manager, Cairo Sherrell monitors team progress, facilitates team meetings;

compiles, edits, and submits deliverables, and serves as the main point of contact

between the project team and stakeholders. He is from Loudoun County, Virginia.

Will Steinhilber is from Centreville, Virginia and has the role of research

analyst/modeler. The research analyst/modeler compiles all literature findings and

heads all physical or analytical modeling. Will has generated computer aided

designs of each component of the alternative food waste disposal system to

demonstrate its functionality and how it is to be connected in the system.

A team contract has been created and signed by the project team that outlines team

roles, procedures, and expectations. The Team Contract and Code of Ethics appears

in Appendix 6.

51

9.2 Project Management

Time, Cost, and Performance Trade-Off Assessment

A priority matrix has been constructed below in Figure 21. The 500 USD per

semester budget provided by the Department of Engineering is fixed and cannot be

exceeded, and was considered to be a constrained criterion. Time was a constrained

criterion as well, for the project is limited to four semesters. Given time and cost are

constraints, the project team has chosen to accept project success as defined in the

Executive Summary.

Time Performance Cost

Constrain X X

Enhance

Accept X

Figure 21: Project Priority Matrix

The project was monitored by the project manager, who worked closely with the

capstone advisor to ensure the project was completed by the project end date. The

project manager delegated tasks among team members with consideration of team

member’s talents and strengths to maximize efficiency, cohesion, and productivity.

The project team also adhered to a Gantt chart that scheduled the completion of

tasks and deliverables such that the project would be complete by the project

deadline.

Gantt Chart

A Gantt chart was created to schedule the project so that it will be completed by

April 18, 2015. The Gantt chart features tasks to be completed and who on the

project team is responsible for its completion. Kyle Groves is represented by the

letter K, while Ciara Middleton, Cairo Sherrell, and Will Steinhilber are represented

by CM, CS, and W respectively. Laboratory operations Professor Scott Padgett is

52

represented by SP. The Gantt chart displayed below as Figure 22 and 23 depict

project progression up to prototyping and the prototyping phase respectively.

Figure 22: Gantt chart displaying project status up to the current status

53

Figure 23: Gantt chart displaying the schedule for the prototyping phase.

10 CONCLUSIONS AND RECOMMENDATIONS

The purpose of this project was to design a system that may reduce methane

emissions of campus food waste disposal processes. By capturing biogas generated

from processing food waste, the system serves to lessen the methane footprint

campus dining facilities have on global warming. The system is not economically

54

sustainable, for more biogas must be generated to offset capital and annual

operating costs, but the system provides an alternative method to manage food

waste such that methane emissions are reduced and biogas is provided as a

renewable energy source.

11 ACKNOWLEDGEMENTS

The project team would like to acknowledge the Department of Engineering faculty,

especially capstone advisor Dr. Adebayo Ogundipe, laboratory operations Professor

Scott Padgett, design instructor Dr. Brad Striebig, and members of previous and

current panels; including Dr. Elise Barrella and Dr. Justin Henriques. The team also

acknowledges Mr. Connor Heede who is alum of the Department of Engineering and

also served as a panel member. The efforts of these individuals to aid the project

team in completing the objectives detailed in this report are recognized and highly

valued.

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manure compost. Thesis Presented to the Faculty of the Graduate School of

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United States” U.S. Department of Energy

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Bacterial Growth Rate in Anaerobic Wastewater Treatment. Vol. 78, No. 2

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Biogas Production from Organic Fraction of Municipal Solid Waste via

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Geological and Mining Engineering Vol:8 No:1, 2014

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Dr. Sunil Kumar. InTech. 2012

58

Appendix 1: Box Models for Subsystems

59

Appendix 2: Feedstock Sample Raw Data

Monday,

March 31,

2014 Noon

Sample Mass

(g)

Volume

(mL) +/-

5%

Bulk

Density

(g/mL)

Temperature

(Celsius) pH

Oxygen

Potential

(mV)

MC

Mass (g)

Moisture Content

(%) (150° Celsius)

1 93.00

95 130.0 0.72 18.1

6.0

2 65.9 1.679 83.13

2 110.8

689 150.0 0.74 17.8 5.5 95.6 1.152 79.84

3 96.33

94 135.0 0.71 18.7

5.7

3 82.5 1.407 80.95

4 89.76

62 130.0 0.69 18.8

5.7

1 83.6 1.453 81.69

60

Appendix 3: Other Concepts

Reactor

Functions

Possible

Solutions

Collect waste McMaster-Carr

Easy-Drain

Polyethylene

Cylindrical

Tank; Prod.

#3687K122

McMaster-Carr

Steel Drum;

Prod. #4115T38

Food waste

Collection Bin;

Patent

CN302297994

S

Waste

Disposal Bin;

Patent

CN202942941

U

Digest waste McMaster-Carr

Liquid Organic

Waste reactor;

Prod.

#9425T52

McMaster-Carr

Granular

Organic Waste

reactor; Prod.

#63785T11

Biogas

Fermentation

Tank; Patent

CN203144393

U

Solar Biogas

Generator;

Patent

CN203112825

U

Produce

effluent

Mobile

Ingredient Bin,

Grainger Item

# 5M685

Waste

Container,

McMaster-Carr

4011T7

Organic

Fertilizer

Production

Process;

Patent

WO20110921

36 A1

Biomass Boiler

Ash

Production

Technology;

Patent

CN103214295

A

61

Produce

biogas

Drum Heater,

Grainger Item

# 3CCZ9

Lead Drum,

McMaster-Carr

9856T314

Biogas

Production

with

Enzymatic

Pre-

Treatment;

Patent

WO20110921

36 A1

Solar Biogas

Generator;

Patent

CN203112825

U

Collect

biogas

Head Drum,

McMaster-Carr

4319T913

Carbon Steel

Drum, Grainger

Item # 1HBH2

Biogas

Collection

Device; Patent

CN203159607

U

System for

Collecting

Biogas

Generated by

Waste; Patent

EP2225052 B1

Contain Gas Burner Portable LP Gas A Container Energy Storage

62

biogas Ignition

Transformer,

Grainger Item

# 23M557

Burners,

McMaster-Carr

3310K42

for Gas; Patent

EP0350455

B1

Device; Patent

EP2528192 A2

Minimize

smell

Grainer RTV

Silicone

Grainer Silicone

Rubber Sealant

Patent

US5133786 -

Method and

apparatus for

minimizing

odor

Patent

US8440316 -

Odor

transmission-

resistant

polymeric film

Purify biogas Silicone

methane

purifier,

Grainger Item

# 65M5657

CAMDA Biogas

Desulfurization

system 100

Patent

US8182576

Patent

US201300196

33

Sense

methane

GRAINGER

Sensor,

Catalytic Sensor,

Methane

Patent

US5985628 -

Patent

US5635628 -

63

content Combustibles

Item # 3LZV3

Item # 36F163

Mfr. Model #

6812950

Method for

detecting

methane

Method for

detecting

methane

Maintain

temperature

GRAINGER

Duct

Insulation, 1-

1/2In x 48In x

25Ft Item #

6ZKK3

GRAINGER

Insulation Sheet,

24 x 48 x 1/2 In

Item # 4NNP3

reactor Patent

US4274838

reactor Patent

#07320753

There was one other concept explored that modeled the natural process of

anaerobic digestion. The process occurs naturally at the bottom of lakes and oceans

in a layer of organic material and mud. This process is copied by creating a small

artificial “lake” with only a thin water and mud layer in order to ensure anaerobic

conditions and a large organic waste layer to digest as much waste as possible. This

concept, seen below, was thrown out because it failed in the beginning part of

concept evaluation when rated against the absolute criteria.

64

Solution Principle-Segmentation (b)

This chamber would let gas through a semipermeable top so that reactor contents

would not penetrate the gas chamber. As more waste is processed, the fill line will

decrease so that the gas chamber could be removed from the reactor. The

modularity of the gas chamber will allow for the reactor to be transportable without

increasing manufacturability.

65

Appendix 4: P3 Guidelines

STATUTORY AUTHORITIES

SWDA: Solid Waste Disposal Act--Section 8001:

Section 8001 of the Solid Waste Disposal Act authorizes the EPA to make grants for

research, investigations, experiments, training, demonstrations, surveys, public

education programs and studies relating to: (1) adverse health and welfare effects

from solid waste; (2) solid waste management programs; (3) resource recovery and

conservation, and hazardous waste management systems; (4) production of usable

forms of recovered resources; (5) waste reduction; (6) improved solid waste

collection and disposal methods; (7) identification of solid waste components; (8)

small scale and low technology solid waste management systems; (9) methods to

improve performance of recovered solid waste; (10) improvements in land disposal

practices; (11) methods for sound disposal of resources, including sludge and coal

slurry; (12) methods of hazardous waste management; and (13) air quality impacts

from the burning of solid waste. (EPA 2013)

RESEARCH AREAS

Biofuels and Waste to Energy

Renewable energy feedstock is an ever increasing area of interest. These

include technologies which address the environmental implications of biofuels

and energy from waste, making their availability and use more sustainable

while potentially mitigating waste management challenges. Areas of interest

include but are not limited to research on:

● Technologies to improve process efficiencies and reduce air and water

emissions and waste disposal impacts from biofuel production.

● Innovative technologies that produce biofuels or energy from waste

materials, including manure and farm wastes, forest wood biomass,

grassland biomass, organic non-recyclable components of municipal

solid waste, bio solids from wastewater treatment plants, meat

rendering, greases and food wastes or other waste material. This

would include research to develop manure-to-energy technologies for

semi-arid or arid climates with high solid content feedstock and to

make anaerobic digesters smaller and easier to operate with lower

installation and maintenance costs.

66

● Cost effective gasification technologies and systems designed to gasify

animal and farm wastes, including wastes from animal feeding

operations (AFOs). (For more information on AFOs, see: Animal

Feeding Operations.)

● Biological systems that produce an enriched, easily transported

feedstock for digester systems. (EPA 2013)

Appendix 5: Bill of Materials

Appendix 6: Team Contract

67

TEAM CODE OF CONDUCT & CONTRACT

Project Name

Design of an Anaerobic Digestion System for Use as an Alternative Food Waste

Disposal Method by JMU Campus Dining Facilities

Team Members & Contact Information

1) Kyle Groves: groveskm@dukes.jmu.edu, (540) 830-2783

2) Ciara Middleton: middlecn@dukes.jmu.edu, (301) 524-7181

3) Cairo Sherrell: sherrecj@dukes.jmu.edu, (703) 975-6460

4) Will Steinhilber: steinhaw@dukes.jmu.edu, (703) 282-6805

Team Roles

Project Manager and Facilitator: Cairo Sherrell

The project manager/facilitator is the main point of contact between the instructor,

stakeholders, and points of contact. Responsibilities of the project

manager/facilitator include compiling, editing, and turning in all deliverables on-

time with appropriate formatting and structure; facilitating meetings to illicit total

participation, productivity, and cohesiveness within the team; delegating team tasks

and responsibilities to maximize efficiency, and monitoring progression of the

project. This position is decided each semester.

Treasurer and Recorder: Ciara Middleton

The treasurer/recorder handles and keeps all project finances and records.

Responsibilities of the treasurer/recorder include making and documenting all

purchases as well as turning in receipts and necessary purchase cards, recording

notes and commentary during all meetings and summarizing each team meeting as

well as keeping these notes and commentary that have been generated. The

68

treasurer/recorder is also responsible for managing the capstone Google Drive

account. This position shall remain unchanged for the entire project duration.

Research Analyst and Modeler: Will Steinhilber

The research analyst/modeler heads all research pertaining to modeling the

anaerobic digestion system as well as compiling all literature findings and

references. This person leads and conducts all computer and mathematical

modeling pertaining to the project.

Machinist and Test Lead: Kyle Groves

The machinist/test lead is responsible for constructing all physical prototypes and

leading and conducting all test procedures that will be conducted to further

modeling and analysis of the anaerobic digestion system.

Team Procedures

1. Day, time, place, and frequency for regular team meetings:

Monday: lunch at 12pm in Festival (weekly)

Wednesday: at 2:30pm in the Pit (weekly)

Sunday: at 9:15pm in The Pit (weekly)

2. Preferred method of communication in order to inform each other of team

meetings, announcements, updates, reminders, problems:

Primary method of communication: messaging through GroupMe app

Secondary method communication: messaging via mobile phone text message

3. Decision-making policy:

We will make our decisions by unanimous consensus. If there is conflict, we will

discuss as a group until we come to a unanimous decision. The capstone advisor will

69

be sought if a unanimous decision cannot be met, to which advisor’s say will be the

ultimate decision.

4. Method for setting and following meeting agendas:

The project manager/facilitator will set each agenda for each meeting prior to the

meeting. The project manager will be responsible for making sure that the agenda is

followed and met during each team meeting.

5. Method of record keeping:

The treasurer/recorder will be responsible for recording all commentary during

team meetings as well as notes and summary. This person will also keep all records

and notes.

Team Expectations

Work Quality

1. Project standards:

A professional level of standard will be held for all deliverables. It is expected that

each assignment and/or deliverable was given maximum effort within the

constraints of time and resources.

2. Strategies to fulfill these standards:

Prioritization and specialization along with teamwork and high, personal work

ethic will help the team fulfill these standards.

Team Participation

1. Strategies to ensure cooperation and equal distribution of tasks:

70

Cooperation and equal distribution of tasks will be ensured through open

communication within the team.

2. Strategies for encouraging/including ideas from all team members:

We will do this by encouraging team members to provide their input on each

decision that is made. The project manager/facilitator is responsible for ensuring

each team member is incorporated during team meetings.

3. Strategies for keeping on task:

An agenda for each team meeting will be made by the project manager/facilitator.

The project manager/facilitator will also make sure the agenda is followed.

4. Preferences for leadership:

The project manager/facilitator will lead team meetings to ensure productivity,

effectiveness, and efficiency. All team members are expected to share responsibility

and risk associated with the project.

Personal Accountability

1. Expected individual attendance, punctuality, and participation at all team

meetings:

Each team member is expected to attend each team meeting on time (within five

minutes of meeting time) unless the team member is sick or has a valid excuse of

absence. Absent team members will notify at least one other team member of

their absence and will coordinate with other team members to minimize the effects

of their absence. Each individual is expected to engage solely in capstone-related

tasks within each team meeting.

2. Expected level of responsibility for fulfilling team assignments, timelines, and

deadlines:

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A professional level of responsibility will be maintained for fulfilling each team

assignment on time and with high quality. All parts of the deliverable that is to be

compiled by the project manager will be given to her/him at their request.

3. Expected level of communication with other team members:

Each team member is expected to openly communicate with the entire team in a

public forum or private forum via the primary method of communication firstly and

the secondary method of communication second. All private communication

pertaining to the project is expected to be brought to a public forum.

4. Expected level of commitment to team decisions and tasks.

Each team member is expected to fully commit to the project within their role and

each team decision that is made. It is encouraged to excel beyond the roles defined

within this team contract and to be fully invested in the team’s decisions and

ultimately its success.

Consequences for Failing to Follow Procedures and Fulfill Expectations

1. Describe, as a group, how you would handle infractions of any of the obligations

of this team contract:

Infractions will be handled by holding the team member who is suspected of

infraction to this team contract. The team will assign an additional task to this

team member as a consequence for causing the infraction.

2. Describe what your team will do if the infractions continue:

If infractions continue, the team will hold a group meeting to discuss the issue and

solutions to be implemented to cease infractions. If infractions continue, the

capstone advisor will be sought to discuss the behavior of the individual

trespassing the team contract and code of conduct.

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Appendix 7: Engineering Drawings

Full System

Filter (all in inches)

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Reactor

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Storage Tank

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Pump

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Stand

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Compressor

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Appendix 8: Team Member Resumes

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