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Final Report - Calvin College

1. 0 0000 r 40 60 80 100 120 140 160 180 200 1 0000 2 0000 y 0 0099x 5 0431 R 0 8721 Series1 3 0000 Linear Series1 4 0000 5 0000 6 0000 time Figure A5 Logarithmic Plot of Bacterial Growth A8 Conclusion Each tube was found to be as predicted first order with respect to the bacteria with specific growth rates determined using method of least squares A first order reaction is in the following form ten KIC e Aas where Ca mol L is the concentration of the bacteria which is directly related to the absorbance measured and k hours is the specific growth rate of the bacteria Combination of Eq 1 and a mole balance yields Eq 2 as follows lnl kt Using graphs such as Figure A5 the above equation can be plotted so k for each growth case can be solved The calculated data is listed in Table A2 Calculation of k Temperature Test Table A2 Calculation of k Temperature Test k hours Standard Deviation Tube 1 Room temp 9 85 E 3 0 55 E 3 Tube 2 Room temp 11 77 E 3 0 75 E 3 Tube 3 Incubator 16 47 E 3 1 56 E 3 Tube 4 Incubator 6 30 E 3 0 83 E 3 This data is somewhat surprising in that it is difficult to tell the temperature effect on the growth rate It was expected and assumed that an increase in temperature would yield a faster growth rate as tube 3 in T
2. Appendix F MSDS Sodium Phosphate Monobasic MonoHydrate i Science Lab com Chemicals amp Laboratory Equipment Material Safety Data Sheet Sodium phosphate monobasic monohydrate MSDS Catalog Codes SLS1165 SLS4009 CAS 10049 21 5 US Sales 1 800 901 7247 RTECS WA1900000 International Sales 1 281 441 4400 TSCA TSCA 8 b inventory No products were found Order Online ScienceLab com CHEMTREC 24HR Emergency Telephone call 1 800 424 9300 International CHEMTREC call 1 703 527 3887 For non emergency assistance call 1 281 441 4400 CAE C Toxicological Data on Ingredients Sodium phosphate monobasic monohydrate LD50 Not available LC50 Not available Potential Acute Health Effects Slightly hazardous in case of skin contact irritant of eye contact irritant of ingestion of inhalati Potential Chronic Health Effects CARCINOGENIC EFFECTS Not available MUTAGENIC EFFECTS Not available TERATOGENIC EFFECTS Not available DEVELOPMENTAL TOXICITY Not available Repeated exposure to a highly toxic material may produce general deterioration of health by an accumulation in one or many human organs Section 4 First Aid Measures p 1 MFC V1 User Manual BioVolt MECHT User Manual BioVolt Bls Vaz USER MANUAL MFC V1 Congratulations on becoming an owner of the MECHT by BioVolt We at BioVolt have taken great care in making sure that this product performs to your expecta
3. The overuse of three materials was tested table salt baking soda and phosphate First a control of the fully substituted media was made Then additional tubes containing 2 5 10 and 100 times the ATCC suggested amount of the ingredient were made up and inoculated The tubes were placed in the 30 C incubator for two weeks Results Table summarizes the results of the experiment Table A3 Robustness Test Experimental Results NaCl Baking Soda Phosphate Control Growth Growth Growth X 2 Growth Growth None X5 Growth Growth None X 10 Growth None None X 100 None None None Conclusion As seen by Table 9 a large excess of salt still yields visible growth In fact it is possible that salt stressed bacteria are more likely to form a stronger bio film Quite a bit of excess baking soda is allowable for still healthy bacteria however any additional phosphate seems to hinder the growth of the bacteria It is possible that the bacteria were still growing in the excess phosphate solution but were not at the visible amount Typically the number of bacteria must be on the order of 10 before they are visible to the naked eye Because of the death or stunted growth of the bacteria under non ideal conditions the user s manual or instructional reading material accompanying the MFC must note the effect of poorly or incorrectly mixed media This experiment also confirmed that optimal performance seems t
4. 3 Insert syringe into an inverted prepped tube and inoculate with all the contents of the syringe Take care to remove air bubbles from the syringe 4 Place in the 30 degree Celsius incubator for best results Filter Sterilizing This procedure is to be done in a sterile environment It was followed after mixing of a new media as an alternative to Autoclave sterilization The VacuCap contains a filter of 0 22 pm which filters out dirt and undesired bacteria 1 Spray gloved hands and the hood surface with IPA Allow it to evaporate Also spray the bottoms of all beakers and bottles placed in the hood 2 Remove VacuCap from packaging Do not touch the bottom surface of the cap as it must remain sterile 3 Attach vacuum tubing to vacuum valve on the cap Attach free tubing to valve labeled inlet on the cap 4 Place the free end of the inlet tubing in media solution 5 Place cap firmly on sterile glass storage bottle 6 Turn on vacuum until all media has filtered through the VacuCap and is in the sterile glass bottle Freezing bacteria This procedure was only done once as a method of long term storage for samples of bacteria The frozen storage of back up bacteria was kept in case of emergency need of cultures 1 Remove metal cap and rubber stopper from Balsh tube 2 Quickly transfer media containing bacteria into a sterile centrifuge tube and flush with nitrogen Remember to shake the Balsh tube before pourin
5. however improper disposal could result in damaging environmental effects Inoculated media should not be disposed of in any body of water as the microorganisms remain viable in anaerobic aqueous solutions An effective disposal technique involves exposure of the bacteria to oxygen and UV light sunlight for one week or boiling for five minutes These methods effectively neutralize the bacteria allowing for safe disposal of the media 5 1 3 2 Safety The MFC is inherently safe Care should be taken when handling electrical devices Proper instructions for connecting and disconnecting an electrical device to the MFC should be followed 6 1 3 8 Health The ingredients in the media are mainly kitchen appropriate materials water baking soda vinegar and table salt If consumed in large quantities patient may experience some discomfort but these materials are safe for handling and even mild consumption Two components necessary in the media that are not substitutable as purchasable kitchen ingredients are ammonium chloride and monobasic monohydrate sodium phosphate Neither of the two components pose serious health risks however ammonium chloride is a mild irritant and slightly acidic pH 5 5 when dissolved in water The MSDS for ammonium chloride and monobasic monohydrate sodium phosphate are provided in Appendices E and F 5 2 Internal Design Alternatives and Analysis 5 2 1 Overview The bacterial species used within the final p
6. To achieve the best possible operation the final prototype must account for all of these concerns Initially the bacteria were grown with a few other components such as sodium fumarate and Wolfe s vitamin and mineral solutions however through a series of experiments Appendix B it was found that the bacteria did not require these components to grow so they have been omitted for the final media The initial ATCC media recipe can be found in Appendix D 5 3 External Design Alternatives and Analysis 5 3 1 Overview Figure 2 Final Prototype Design Cathode Chamber The final prototype includes a three chambered design The prototype is designed to be fully enclosed to minimize the risk of anode chamber contamination and protect the bacteria from exposure to sunlight and oxygen The design incorporates threaded caps that allow for the prototype to be transported easily without creating a spill hazard Design Component Descriptions Media Storage Chamber The Media Storage Chamber is where fresh media is stored for later use within the cell The volume of the Media Storage Chamber is adequate to provide full media replacement of the Anode Chamber and under the suggested operating procedures can last up to two months Anode Chamber The Anode Chamber is completely sealed with the exception of a service port to drain and or fill the chamber initially The Anode Chamber is filled completely with the nutrient media and
7. di i l ical device to the MFC V1 should be taken Isc nnecting an eiecticat cvice to tie e SS Figure 1 Schematic showing the biology and operation of the MFC V1 5 4 PRODUCT OVERVIEW 4 1 How IT WORKS The MFC gets its electricity by harnessing the metabolism of 6 a certain type of bacteria Geobacter sulfurreducens This bacteria eats 4 2 CELL LAYOUT the food solution called the media in biological terms and gives off electrons as shown in Figure 1 below By continuing to feed the bacteria the prescribed media bacteria in the cell can grow and continue to produce electricity The bacteria are fed by filling the media storage chamber with fresh media and injecting the new media into the anode chamber via the injection pump system Any waste media is then discarded out of the waste stream MFC V1 User Manual BioVolt MFC V1 User Manual BioVolt 002 Figure 2 Full cell cutaway with part numbers 006 Figure 3 Cell end cap 012 013 011 008 Figure 5 Anode chamber close up view Figure 4 Injection apparatus close up view 015 MFC V1 User Manual BioVolt MECHT User Manual BioVolt Figure 6 Cathode chamber close up view 4 3 PARTS LIST 001 Media Storage Chamber 9 002 Anode Chamber 5 CARING FOR THE BACTERIA 003 Cathode Chamber 5 1 HEALTH CONSIDERATIONS 004 Waste Outlet Several simple steps are necessary for Geobacter sulfurreducens 005 Level Indicator the bacteria use
8. nm with well visible results Dumas et al 2495 This data gave a concentration profile mapping the growth of the bacteria It also gave insight to the variance of growth due to temperature Bacterial Growth Curve Lag Log Death Phase Phase Stationary Phase Phase Number of Microbes Time Figure A2 Bacterial Growth Curve Electrode Surface Area to Chamber Volume Effect on Kinetics 2 Large Large 1 Large 1 Small Ei E 5 2 Eai 5 O o Sp o gt 1 Small 6 7 8 Days of Operation Figure A3 SA V Kinetics Data Results This absorbance data as a function of time was collected then was plotted using the integral method to determine the order of the reaction A plot of the data from two of the tubes is shown in Figure A4 and a logarithmic plot of one of the runs is shown in Figure A5 depicting the integral method and displaying a first order reaction It was also determined that the surface area to volume ratio that obtained the best results was the test with one large electrode in the research prototype chamber approximately 1 in2 1 in Absorbance units 0 05 Kinetics Experiment 0 045 0 04 0 035 0 03 0 025 0 02 0 015 0 01 0 005 40 60 80 100 120 140 160 180 200 Hours Room Temp Incubator In Ca Figure A4 Example of Kinetics Experiment Results 1st order
9. MFC is the low power production compared to the prototype s size Different possibilities exist which could improve this design and increase the power output of the cell while maintaining or even decreasing overall size The most influential improvement which could be made is adding a catalyst to the cathode electrodes which could catalyze the reduction of molecular oxygen to water Different catalysts could be researched however literature has shown platinum to be a highly effective catalyst for this reaction Power production of 1 000 to 10 000 times that of BioVolt s prototype have been shown using graphite electrodes with platinum loadings as low as 0 5mg cm Trinh et al 752 The surface area of cathode electrode used in BioVolt s prototype would require approximately 50mg of platinum but the overall surface area of the cathode electrodes must be optimized with the platinum loaded electrodes and may be significantly less or more than the surface area used in BioVolt s prototype This research was not implemented in this project because the production of platinum loaded electrodes was not feasible due to a lack of equipment at Calvin College for such production and the cost restraints of procuring platinum loaded electrodes In addition to introducing a catalyst to the cathodic chamber MFCs have been constructed which rely on a different reduction reaction occurring at the cathode Du et al 13 By employing a different reduction
10. The MFC does not produce any power MFC V1 User Manual BioVolt Solution There may be a loose connection on one of the terminals Tighten all connections and retry Problem The MFC still is not producing any power Solution Feed the bacteria 50 pumps of media using the injection pump Problem The media in the media storage chamber is very cloudy Solution It has other species of bacteria growing in it Dump and refill Problem I ran out of some ingredients Solution Order all supplies from BioVolt online at biovolt org or over the phone at 1 800 BioVolt Problem Any problems we were unable to answer here Solution Call BioVolt Monday Friday 8 00AM 5 00PM GMT 05 00 Eastern Time US amp Canada and one of our trained technicians will assist you 14 11 GLOSSARY OF TERMS ammonium chloride an ingredient in the media anode the negative terminal or side of a battery or fuel cell bacterial media the food solution for the bacteria baking soda an ingredient in the media MFC V1 User Manual BioVolt buffer any solution which resists changes in pH cathode the positive terminal or side of a battery or fuel cell cutaway a view where some of the structure is removed to reveal previously unseen parts dibasic sodium phosphate see sodium phosphate dissolved no visible solids remain in a liquid hex key a hexagonally shaped piece of metal bent at a right angle Used for turnin
11. by providing more surface area on which the bacteria is able to grow Increasing the surface area of the electrode would increase the amount of bacterial biofilm and decrease the residence time of the media Research is needed into how often the user would be willing to replace the media By replacing the media more often more power is achievable for a given volume For optimization to be achieved further research could have been conducted into the necessary size ratio of each of the chambers specifically the cathode and media storage chamber size compared to the anode chamber It was assumed that each of the three chambers should be approximately the same size however if it is possible to decrease the relative size of one of these chambers without effecting power production the overall power production per size of the final MFC anode cathode and media storage chamber could be increased Another experiment that would have been useful had the resources been available would have been a study of the power production as a function of MFC volume It was assumed that the size of the MFC directly and proportionally affects the power output But it is also possible that there is a maximum point where the tradeoff between size and efficiency is no longer directly related This would have helped with the size selection of the final prototype Alternatively other designs of microbial fuel cells could be investigated BioVolt worked with
12. electrical production The power output of the cell can be improved 1 000 to 10 000 times that of this prototype by the addition of a platinum catalyst to the cathode electrodes approximately 50mg of platinum are needed and 10 to 100 times by using a bacterial cocktail in the anode chamber Further research is needed with these cases before implementation however this research is beyond the scope of BioVolt s project 1 Introduction Alternative energy is a highly discussed subject in today s society and is also an area of extensive research As part of the Bachelor s of Engineering degree at Calvin College senior engineering students form teams and spend both semesters of their senior year attending a class called Senior Design ENGR 339 340 The intent of this series of classes is to work as a group and tackle a project of the teams choosing Team 1 BioVolt comprised of four chemical engineering students chose to take on a project that covers alternative energy and in particular the production of electricity using a microbial fuel cell MFC Certain bacterial species in the course of their normal cycles of metabolism and respiration have the ability to transport electrons that are produced during these processes to materials outside of the cell membrane While this act of transporting electrons outside of the cell membrane is specific to only a few bacterial species recent studies have shown that by providing the correct strai
13. given to these donors on page 33 Table 2 is a list of expenses pertaining to the project if all aspects of the design were purchased Table 1 Actual Prototype Budget Part Cost Qty Where acquired G sulfurreducens 195 1 ATCC G sulfurreducens shipping 109 1 ATCC Wolfe s Mineral Solution 50 1 ATCC Wolfe s Vitamin Solution 50 1 ATCC Bacteria Medium Solution 0 SC Calvin Biology Dept Cell Electrodes 23 4 HobbyLinc com Pump 12 1 Construction Material for 20 Lowes research prototypes Construction Materials for 23 Lowes final cell Ultrex Proton Exchange 0 1 Membranesinternational com Membrane Total 482 Table 2 Full Cost Theoretical Prototype Budget Part Cost Qty Where acquired G sulfurreducens 195 1 ATCC G sulfurreducens shipping 109 1 ATCC Wolfe s Mineral Solution 50 1 ATCC Wolfe s Vitamin Solution 50 1 ATCC Bacteria Medium Solution 36 1 of each Calvin Biology Dept Aldi and buffer ingredient Cell Electrodes 23 4 HobbyLinc com Pump 12 1 Construction Material for 20 Lowes research prototypes Construction Materials for 23 Lowes final cell Ultrex Proton Exchange 20 1 Membranesinternational com Membrane Total 538 4 2 Production Budget Economic Analysis If this prototype were produced on a commercial scale the unit cost would be dramatically reduced from the prototype cost Here th
14. is 75 4 2 2 Construction Materials Commercially more cost effective materials will be used to construct the MFCs Instead of PVC pipe the cell casing will be constructed out of blow molded HDPE at an estimated production cost of 1 30 per complete unit The prototype contains a round roughly nine square inch membrane By altering the configuration of the membrane used for commercial production to a 3x3 square the same surface area can be achieved with almost no scrap per membrane Based on a ten thousand unit production purchasing the membrane in bulk quantities results in a per unit cost of 47 The feed system consists of a primer bulb one foot of Tygon tubing a silicon check valve and a 0 22 micron filter Assuming the primer bulb is purchased and not manufactured in house the total cost of the pump feed system for a ten thousand unit basis is 91 per unit plus 6 per unit for the filters Based upon an eight plus four electrode setup each being four inches long the total cost per unit for the electrodes is approximately 96 The cost per unit for all of the electrical components wiring terminals terminal epoxy etc totals 28 Thus commercially producing ten thousand units would result in a materials cost of 4 71 per unit 4 2 3 Operating Costs To produce ten thousand units there would need to be facilities large enough to handle the microbiological growth requirements Machines would have to be p
15. night Panel Review Assembly and testing Inventor model Research prototype shell Aquire other components agar electrodes Research prototype construction Bacteria growth and testing in cell Demo with voltmeter Create other research prototypes Cell optimization Final cell construction Final design test run Figure 3 Spring semester Gantt chart 4 Project Budget 4 1 Prototype Budget This project was funded by the Calvin College Engineering Department An initial amount of 300 was allotted to BioVolt as a suggested project budget After calculating a rough estimate of the project budget including design materials bacteria cultures and bacterial growth nutrients it was projected that the materials needed for construction would total 295 This budget was revised based on the cost of purchasing the Geobacter sulfurreducens and a new budget of 500 was proposed Critical decisions were made before purchasing any component of the MFC prototype and the budget was updated following each purchase The updated budget was reviewed each week during weekly meetings and important issues concerning the budget were handled Table 1 is a list of final expenses relating to the completion of the project A few items specifically the Ultrex membrane and the media ingredients were donated to BioVolt and therefore have a cost of 0 Appropriate acknowledgements are
16. oot aces sve A Ea a eai 25 Cell Feed System Decision Mats 28 Proton Exchange Membrane Decision Matrizs 30 Executive Summary Microbial fuel cells MFCs are an emergent technology that offers a novel approach to small scale electrical power generation that could be useful for recharging batteries for use in cameras medical devices or other battery operated devices in areas without access to the capital needed for more traditional means of electrical generation BioVolt designed optimized and constructed a prototype MFC that built upon existing research making an electricity generating device that is more cost effective BioVolt s final prototype consists of a cell casing made of polyvinyl chloride PVC an Ultrex proton exchange membrane a set of eight plain graphite electrodes in the anode where the biofilm of bacteria is deposited a set of four graphite electrodes in the cathode where the reduction of oxygen to water takes place and a filter pump system attached to a media storage chamber for the semi continuous injection of clean media into the anode BioVolt also designed a simplified inexpensive media solution composed of vinegar baking soda and a salt solution The functional prototype produces 0 5yW at 0 6V provides ten days of use before one third of the media must be refreshed is portable operates on a feed obtainable by the user and proves the validity of the concept of using an MFC for inexpensive small scale
17. operate an injection pump which would fill the anode bacterial chamber and simultaneously empty used media through a check valve system Using an immiscible liquid would require the user to pour in fresh media into the anode and then drain used media from the anode to maintain the liquid level This system would require the user to keep the liquid at the correct level manually and would leave the system open to user error which could result in the loss of the immiscible liquid layer and failure of the system The syringe injection system would work much like the system with the immiscible liquid This system however necessitates the use of sharp needles which create a hazard to the customer that the other designs do not Both a pump system and syringe system are relatively intuitive Both use simple technology with which many people are familiar and require simple maintenance which could be easily performed by the user The immiscible liquid design is less intuitive because the barrier which keeps out excess oxygen is a layer of liquid While this may be just as effective it does not have the same type of intuitive design displayed by the other systems For BioVolt s MFC to be widely adapted it is very important that the MFC is very reliable Because the feed system is a part of the design which does not affect power production it is even more important that this aspect of design is very reliable Because of the possibility of spillage t
18. reaction other than the reduction of oxygen to water a higher voltage and power could be achieved The highest reported power outputs have been realized using ferricyanide as the electron acceptor in the cathodic chamber These reported power outputs reach as much as 100 000 times the output of BioVolt s prototype However the use of an electron acceptor such as ferricyanide may incur negative consequences such as health concerns or greater expense Biologically the power production capabilities could be tuned by incorporating other species of bacteria and or adapting the bacteria to function more efficiently Research has shown that a cocktail of different bacterial species has the potential to increase output 10 to 100 times that of Geobacter sulfurreducens Rabaey et al 294 While using a bacterial cocktail would increase the cost of a prototype due to multiple bacterial species must be purchased it may not significantly increase the cost of a production model MFC Further research in this area is needed but is beyond the scope of BioVolt s project because the acquisition of several bacterial species was not possible while maintaining BioVolt s project budget Different graphite materials used in the construction of the anode electrodes such as graphite foam also show promise for increasing power production Dumas 2495 This provides a much higher surface area per volume of the electrode and could increase power production
19. s warranty 3 ENVIRONMENT HEALTH AND SAFETY 3 1 ENVIRONMENT The operation of the MFC V1 is environmentally friendly as it is utilizing natural processes to create your power The bacteria waste is in two forms the used liquid media and CO gas A small amount of CO is produced as the bacteria consume the nutrients and this gas waste is expelled from the anode chamber as you refill or pump in new media The used media that exits the chamber is only a salt solution and can be disposed of with no harm to the environment 3 2 HEALTH Most of the ingredients in the media solution are kitchen appropriate and pose no harm if handled or ingested If consumed in MFC V1 User Manual BioVolt MFC V1 User Manual BioVolt large quantities patient may experience some discomfort The sodium phosphate and ammonium chloride are less common items but also pose no health threats due to exposure to the user Ammonium chloride and phosphate are noted as mild skin irritants Load and the chloride is slightly acidic when dissolved in water so should be handled with care Should you experience any irritation or discomfort wash area with soap and water Seek medical attention if further irritation develops The MSDS sheets for these compounds are included Electrode Electrode 3 3 SAFETY Gg Cathode Chamber Care should be taken when working with any device that carries an electrical charge Proper care for connecting and SR reegt
20. was the power achievable by the given microbe In the literature certain species outperformed others on a regular basis Specifically the Geobacter strains yielded higher power output per electrode surface area than did the Rhodoferax Rabeay 294 With power production capability being such an important design specification it is weighted heavily in Table 4 As shown in the decision matrix Geobacter sulfurreducens proved to be the best overall choice of bacteria for BioVolt s needs 5 2 3 Media Habitat To reduce the cost associated with the microbial habitat BioVolt designed a feed solution for the final cell which was comprised of vinegar baking soda non iodized table salt ammonium chloride and sodium phosphate as shown in Table 5 This solution was used to ensure that all of the materials in the feed were low cost and easily accessible following the design norm of stewardship and cultural appropriateness 19 Table 5 Media Recipe Medium Component Amount g L Sodium Chloride 1 5 Sodium Phosphate 0 6 Morton salt 0 1 Baking soda 2 5 Vinegar 0 82 The pH of the solution for Geobacter sulfurreducens must remain relatively neutral 6 8 7 0 pH The medium created for these organisms must also remain essentially sterile Maintaining a sterile media reduces the risk of contamination with other competing microbes In addition the bacteria must not be exposed to large amounts of UV light or oxygen
21. 0 60 80 100 120 140 160 180 y 0 0063x 4 6554 R 0 5397 m Tube 4 in the incubator time Media Ingredient Omission Experiment Experimental Set Up Although three of the original lab grade ingredients had been substituted and one ingredient was deemed unnecessary there were still two components dibasic sodium phosphate and ammonium chloride which did not have close substitutes outside the laboratory The following experiment was created to test how crucial these components were to the health and growth of the bacteria Four different media were mixed each made with the tested substitutable ingredients i e vinegar baking soda and salt However three of the four media were each lacking one or both of the phosphate or chloride components The first media was a control which contained the ATCC specified amount of phosphate and ammonium chloride The second media did not contain any phosphate component and the third did not contain any ammonium chloride Finally the fourth media did not have phosphate or ammonium chloride but only the substitutable ingredients Each media was dispersed into two tubes of 5 mL each and all were inoculated at the same time All the tubes were placed in the 30 C incubator for two weeks Results Of all the tubes set to grow the only ones that displayed any growth were tubes containing the control media None of the omission tests were successful C
22. Final pH of medium should be approximately 6 8 Wolfe s Vitamin Solution Available from ATCC as a sterile ready to use liquid Vitamin Supplement catalog no MD VS BOUIN fiissieiccrasiatheeenncinstencie aaasexececneed donee tesadeieeanevngsenepcacnestertiees 2 0 mg HQ HG acidas eeen EE da ve eae Deg Ze ee Eed 2 0 mg Pyridoxine bvdrochlonde 10 0 mg Thiamine OI eege 5 0 mg FR OFLA VAN eere cewek cevesas Sek Seege E eeh Cees 5 0 mg Nee DEE 5 0 mg Calcium D C Lpantotbengate 5 0 mg KRICH BQ ciscecsblccuavesvssstvavcevecchbed dev een i a e ea eE E REEE 0 1 mg p Aminobenzoic acd eee cess ceceseecessecessesececeeeeeessececseseeesneeeess 5 0 mg ee eure la ls een eeaer rn ee TTe ren a ct errr terr errr 5 0 mg Distilled water 1 0L Modified Wolfe s Minerals WEIT E EE 10 0 mg INIGI2 E 2A O E E 10 0 mg Na WO4 2H2O E 10 0 mg Wolfe s Mineral Solution see below LOL Wolfe s Mineral Solution Available from ATCC as a sterile ready to use liquid Trace Mineral Supplement catalog no MD TMS Nitrilotriace e DEE 1 5g MeSO4 7H20 EE 3 0 g Mi S O42 O E T Gasvctatsedesagisstis odidesstadeastasitanacce tess 0 5g IN A CU ees 25 ihe see ek Eeer ee OO EE een 1 0 g FES OF H2O EE o l g CoCl2 EI EE 0 1 g WA CTI s25 2535s a a a steve veisaiee hehe dion erase Die Kg eg KE WEE Die COoSCH SSC deed 0 01 g AIK SO4 2 SBS ccssscekccsasvecdccaverceu dee EENS 0 01 g EE 0 01 g Na2M004 2 KREE 0 01 g Distilled waters EE 1 0L Add nitrilotriacetic acid
23. Prototypes Since one goal for the final design was to optimize the feed so that the cell can operate utilizing cheap and readily available materials there was a need for experimental prototypes that could be used to easily compare the effects changing different variables would have on the system To provide this need of experimental prototypes five identical cells were constructed as defined below Fill Cap we Anode Cathode Salt Bridge Figure Al Experimental Prototype Design The experimental prototypes are built upon a classic H design that many researchers use for microbial fuel cells The cells were constructed using 1 inch PVC piping and various PVC fittings The pipes and fittings were glued together to prevent leaks and to prevent contamination from the environment The pipe containing the salt bridge however was not glued to facilitate with the ease of changing the salt bridge between experiments Design Component Descriptions Cathode Chamber The Cathode Chamber holds the Cathode Electrode in an aqueous solution The final reaction reduction of oxygen occurs in this chamber Cathode Electrode The Cathode Electrode is composed of graphite since the material of construction was already decided before testing began in the experimental prototypes Salt Bridge Since Proton Exchange Membranes are very expensive and fragile an agar salt bridge was used instead The salt bridge performs the same functi
24. TEAM 1 BIOVOLT The Research and Development of a Microbial Fuel Cell Lindsay Arnold Jeff Christians Diane Esquivel Andrew Huizenga 5 12 2010 2010 Calvin College and Lindsay Arnold Jeff Christians Diane Esquivel and Andrew Huizenga Table of Contents Ex c tiye EUR 5 NEE te EE 6 2 PONSA 15 Te Te 7 2 1 ee EE H 2 2 EE H 2 2 1 Sustainability sic cdccecanieiatecsvcaeaceatiataasia ease ieencdcane wine omental 7 Deo Etgen 7 223 MOCO E 7 22 4 EE 8 2 2 5 Power ge 8 3 Project leren 8 3 1 W rk Breakdowi Structure ssirnasicaciesenuaniwndamnentamenisas nee i Eres EEn REES 8 NEE noina E iad ia E a ERE hee 9 E E E 11 41 Prototyp EE 11 4 2 Production Budget Economic Analysis w iccsccecsccscisiesscsivecascinsedestaasvatdiesdbenrsnsuesdarsuevavounts 12 4 2 1 Biological Costs sici zate capi seta chet ves lie aes aee A E E EE EEEN E E EEEE EEES 13 4 2 2 Construction leet erger 13 423 Operating COStS sierairanos senses eons n e eE ates eaten taeda a a 14 5 EE 14 5 1 Design Considerations and Criteria ethesch ere ueg een 14 5 1 1 erregt EE ee isisisi aneii den isast 14 Mate Design E 15 5 1 3 Environment Safety and Health siccvocs csscdessacosicanccatcasasnsieicoiavnn iecawieaiarasieatamnniasweroans 17 5 2 Internal Design Alternatives and Analyse 18 5 2 1 EEN 18 5 2 2 Bacteria e 18 5 2 3 Media Ee E 19 5 3 External Design Alternatives and Analysis 0 ccccccesesscsssssseseeessesceeseecesaeceesaesaeeseeae
25. able PVC was selected due to its increased durability and relative expense as shown in Table 6 The following decision matrix shows the two main materials steel and PVC that were considered for the construction of the cell case Both materials were given a score from 0 to 10 points in four categories each weighted respectively to how important that aspect is to the design The scores are multiplied by the category weights to achieve a final score for each material in question The material with the highest combined final score proves to be the best material based upon the design categories Table 6 Cell Casing Decision Matrix Category We i Steel Dee DVC PVC Subscore Availability 20 10 2 9 1 8 Inexpensive 25 7 1 75 9 2 25 Opaquacity 10 10 1 10 1 Durability 35 7 2 45 9 3 15 Workability 10 9 0 9 9 0 9 Final Score 100 8 1 9 1 5 3 3 Electrodes Previous literature examples of MFCs using Geobacter sulfurreducens have used several different materials for the anode and cathode electrodes Dumas et al 2495 The most widely used and inexpensive materials were stainless steel and various forms of graphite Both stainless steel and graphite were shown to produce comparable results Different types of graphite were evaluated such as graphite foam woven graphite plain graphite rods and carbon paper Rabaey 294 Platinum plated graphite electrodes proved to perform better than non platinum pl
26. able show when compared to tubes 1 and 2 However tube 4 whether due to extraneous variables error or natural causes was the slowest growing of the test With only these two tests at different temperatures it s hard to infer a relationship with temperature However it is reasonable to assume based on this data that the MFC would function sufficiently in most ambient temperatures However the specific growth rates are accurate enough to give a general picture of growth of the Geobacter under standard conditions The average k 11 10 E 3 hours when the concentration is found using absorbance units From other old samples it was A9 noted that the highest absorbance reached when the tube was cloudy with bacteria was about 0 10 Using an ordinary differential equations solver program to graph Eq 2 Figure A6 was created as a prediction of the logarithmic growth stage of the bacteria It is predicted that the bacteria will reach the end of the log growth stage around 240 hours or approximately 10 days in 5 mL of media in a static environment Therefore if would be appropriate to introduce fresh nutrient rich media to the MFC about one every two weeks This would allow for logarithmic growth to occur and the food of the cell to be used up However instead of allowing the cells to reach a stationary phase the addition of nutrients in the form of fresh feed would allow for the bacteria to reenter a prosperous stage Log Growth of bact
27. at room temperature Kinetics Experiment 0 05 0 045 0 04 0 035 Tube 2 atroom temperature 0 025 Absorbance units 0 02 0 015 0 005 Hours Kinetics Experiment Results for tube 3 in the incubator Kinetics Experiment 0 045 0 035 0 03 m Tube 3 in the incubator 0 025 Absorbance units 0 015 0 01 0 005 0 20 40 60 80 100 120 140 160 180 200 Hours Kinetics Experiment Results for tube 4 in the incubator Kinetics Experiment 0 045 0 035 Tube 4 in the incubator 0 025 Absorbance units 0 02 0 015 0 01 0 005 0 20 40 60 80 100 120 140 160 180 200 Logarithmic plot of bacterial growth tube 2 at room temperature 1st order 0 0000 T T T T T T r T r 20 40 60 80 100 120 140 160 180 200 1 0000 2 0000 y 0 0118x 5 0592 Tube 2 at room 3 0000 RO O64 D temperature In Ca 4 0000 5 0000 6 0000 time A12 Logarithmic plot of bacterial growth tube 3 in the incubator 0 0000 1 0000 2 0000 3 0000 In Ca 4 0000 5 0000 6 0000 1st order 20 40 60 80 100 120 140 160 180 y 0 0152x 5 5416 R 0 7217 R a mp Tube 3 in the incubator time Logarithmic plot of bacterial growth tube 4 in the incubator In Ca 2 3 1st order 20 4
28. ated graphite or stainless steel electrodes but are quite expensive for prototyping Based upon cost alone electrodes for both chambers made of plain graphite were chosen as the optimal material for the prototype design 5 3 4 Feed System Geobacter sulfurreducens is both oxygen and UV light sensitive and must be isolated from outside bacterial species Because of this a simple feed system was designed which required no laboratory skills or equipment and does not expose the bacteria in the anode chamber to large amounts of oxygen UV light or foreign bacteria Several different possible designs were evaluated including injection of the bacteria via a syringe a pump system and creating a physical barrier via an immiscible liquid layer A pump system was chosen for the final prototype based on evaluation of each of the possible options against the following criteria e Isolation from Oxygen The feed system must isolate the bacteria from oxygen acceptably to be a valid option for implementation e Isolation from Outside Bacteria To produce and MFC which can operate for extended periods of time all competing bacterial species must be eradicated e Ease of Use The system should be easy to use and maintain so the MFC is a hassle free means of power production e Intuitive Design In keeping with the design norm of transparency the feed system design should be clear and intuitive so the consumer is able to understand use and mainta
29. contains the microorganisms as well as the electrodes upon which the organisms grow Cathode Chamber The Cathode Chamber is open to the atmosphere under normal operating conditions although a threaded cap is provided to prevent leakage during transportation of the cell The electrodes are submerged in an aqueous buffer solution providing ideal conditions for the reduction reaction to occur with oxygen completing the electrical circuit Figure 3 Injection apparatus close up view Media Injector The media injector is a primer bulb that takes media stored in the Media Storage Chamber and pumps it through the Pre Injection Filter and into the sealed Anode Chamber Media Outlet The Media Outlet is connected to the Anode Chamber using a one way valve When the pressure in the Anode Chamber is increased by the injection of new media spent media is ejected through tubing to the Media Outlet located on the end cap Pre Injection Filter This is a replaceable filter that is rated for 0 22 microns used to filter the media as it is pumped from the Media Storage Chamber to the Anode Chamber The filter resides behind the Media Storage Chamber end cap which is removable so as to facilitate filter replacements Level Indicator The level indicator is a tube connecting the top of the Media Storage Chamber to the bottom of the chamber This allows a visual indication of how full the Storage Chamber is without having to re
30. cterial media and produces electrical power which the MFC V1 harnesses More information about your new MFC can be obtained by calling or emailing BioVolt at 1 800 BIOVOLT service biovolt org or find us online at MFC V1 User Manual BioVolt biovolt org NOTE ALL CONTACT INFORMATION IS FOR DEMONSTRATION PURPOSES FOR THIS DOCUMENT ONLY AND IS IN NO WAY AFFILIATED WITH BIOVOLT OR ANY OF ITS TEAM MEMBERS 2 INCLUDED WITH THE MFC V1 2 1 BACTERIA The species of bacteria included with the MFC V1 is called Geobacter sulfurreducens Proper care instructions are outlined in 5 CARING FOR THE BACTERIA 2 2 FEED MATERIALS Sodium Phosphate Monobasic Sodium Phosphate Dibasic Ammonium Chloride Baking Soda if requested Non lodized Salt if requested White Vinegar if requested 2 3 PARTS AND TOOLS 12 replacement filters Part 009 MECHT User Manual BioVolt e 1 8 inch hex key Part 018 Measuring spoons if requested 2 4 WARRANTY If at any time within the first year of ownership you experience any manufacturing default you may send it back and BioVolt will fix or replace it at no charge to you Also if at any time the bacteria die of natural causes or your MFC V1 ceases operation BioVolt will replace it at no cost user pays shipping and handling charges Modifications to this product or operation of this product in any way other than outlined in this manual could void the manufacturer
31. d better than expected but their lack of performance and general difficulty with use deemed them unacceptable for use in the final prototype However because of their low cost salt bridges were used in the experimental prototypes The Ultrex membrane was chosen as the best option to use as the PEM partly because it is less susceptible to fouling than Nafion but mainly because BioVolt found a distributor of Ultrex membranes that was willing to send a sample size membrane for use in the final prototype for no charge 29 The following decision matrix compares the four PEM options ranked against different categories of design criteria Table 8 Proton Exchange Membrane Decision Matrix Salt Category d Nafion Ultrex Cellophane Category Weight Naren Subscore re Subscore SSES Subscore Sech ubscore aa 20 8 1 6 9 1 8 5 1 0 2 actor 6 6 2 4 6 5 4 5 4 Performance The performance of the MFC was monitored by observing the voltage as a function of time The results are displayed in Figure 6 As seen in this figure a semi steady output was attained after two weeks of operation Prototype Output Voltage mV 10 15 Days of Operation Figure 6 Prototype Voltage Output Media was added on day 7 as was suggested by the kinetics experiments to maximize bacterial growth on the electrodes The addition of fresh media agitated and disturbed the forming biofilm resulting in a temporary loss of
32. d in the MFC V1 to remain in peak health 006 Injection Pump 007 Media Storag e Chamber Fill C ap e Always follow the media recipe accurately 008 Injection Hose e Ensure only clean water is used in the MFC 009 Bacterial Filter e Never leave the anode chamber open to air 010 Media Storage e DE SEH Cap e Avoid exposure of the bacteria to direct sunlight 011 Anode Terminal e Follow all procedures outline in this manual 012 Proton Exchange Membrane 013 Graphite Electrodes 014 Insulated Copper Wire 015 Anode Fill Plug 22 E EECH E E H016 Cathode Tetiniaal e media solution as een speca 1Ca y es gne or the 017 Cathode Chamber Fill Cap feed for the bacteria is vinegar the main component of which is called 018 Drain Hex Key acetate The bacteria digesting vinegar creates the power of the MFC V1 Sodium phosphate acts as a phosphate source and ammonium optimal health of the bacteria as well as optimal power output The chloride acts as a nitrogen source to promote bacterial growth and health Baking soda makes the media less acidic so that the bacteria is able to survive in the media Table salt provides the bacteria with a source of sodium which helps to promote bacterial health MFC V1 User Manual BioVolt 10 6 GETTING STARTED 6 1 INITIAL SETUP After receiving the cell follow the instructions for making media given in 7 1 MEDIA RECIPE Make a 3x batch of media to initially fill the anode and media storage cha
33. dition of sodium fumarate vitamins and minerals for cost and simplicity purposes as these ingredients are not crucial for the survival of the culture 1 Sterilize the injection sites by swabbing the tops of the Balsh tubes with 75 ethanol followed by flame 2 Using a 1 mL sterile syringe with sterile tip add 0 5 mL of sodium fumarate to the tubes to be inoculated Take care to remove air bubbles from syringe before injecting into the tube Also tubes should be tipped upside down to maintain a seal as the syringe is inserted and removed 3 Repeat this procedure when adding 0 1 mL of Wolffe s vitamin solution and 0 1 mL of Wolffe s mineral solution A16 Bacteria transfers The following procedure was used when transferring bacteria into experimental tubes or further culturing tubes The grown bacteria tube should contain bacteria grown for at least five days but no longer than two weeks The tube to be inoculated should have been Autoclave sterilized to ensure no competing bacteria 1 Sterilize the injection sites on both the tube with grown bacteria and the tube to be inoculated Swab the tops with 75 ethanol followed by flame 2 Shake the tube containing the bacteria as a biofilm of cultures will have formed on the bottom of the Balsh tube Tip the tube upside down when inserting sterile 1mL syringe with sterile tip 3 Draw up about 1 mL of bacteria media Remove syringe with tube still tipped to maintain a seal
34. e constructed prototype depends upon the performance of the PEM e Fouling Factor Since the PEM is not replaceable the fouling factor determines how long the cell will last before it is affected by an inefficient PEM e Cost PEMs are generally quite expensive The PEM expense could determine if the MFC is cost effective to manufacture or not Based upon the design criteria four options for membranes were chosen and compared in a decision matrix as shown in Table 8 Nafion and Ultrex are competing brands of PEMs used typically in the electroplating industry and fuel cell industry Drawbacks to these PEMs are that they are relatively expensive and more so with the Nafion tend to foul if in the presence of chlorine Cellophane was indicated in some of the literature as an appropriate membrane but little research could be found about using cellophane membranes in MFCs because many recent research documents use either a Nafion or an Ultrex membrane Salt bridges are simple to construct and are quite inexpensive Their drawbacks however include a high internal electrical resistance as well as generally poor reliability Salt bridges were included in the decision matrix nonetheless because of their low expense and wide availability Due to performance issues the Nafion and Ultrex membranes were chosen as the desired PEM despite their high cost Cellophane scored low overall and was subsequently not considered for use as a PEM Salt bridges score
35. e production cell unit cost is divided into three sections the biological costs the materials costs and the yearly media costs The total per unit material cost based upon a ten thousand unit production totals a conservative estimate of 7 71 Table 3 Estimated Production Unit Materials Cost Part Cost Biological Costs 0 75 Cell Electrodes 0 96 Pump 0 91 Casing Material 1 30 Ultrex Proton Exchange Membrane 0 47 Media Costs 3 00 0 22 Micron Filter 0 06 Electrical Components 0 26 Total 7 71 4 2 1 Biological Costs On a commercial scale the bacterial cost is an initial onetime cost plus the cost of growing and farming the bacteria cultures Once there is an initial source of bacteria the bacteria multiply if given the proper habitat and nutrition so the only cost associated with the biological aspect of the design is the cost of maintaining the bacterial growth and farming cultures of the bacteria for use within a cell Costs associated with farming the bacteria not including facilities and operating costs are only associated with the cost of the nutrient feed material The cost of the media is minimal chemicals can be purchased in bulk and the concentration of each chemical in the media is low It is estimated that for a production of ten thousand units a conservative cost estimate of the biological components per unit
36. ed filmy substance 7 Media substituted with baking soda Very good growth film covering bottom 8 Media substituted with baking soda Excellent growth suspended filmy substance 9 Media substituted with vinegar Ok growth some floating clumps visible 10 Media substituted with vinegar Excellent growth suspended filmy substance Conclusion As seen in Table all of the variations sustained adequate growth enough to be visible in a bio film form This suggests that potassium is not essential in the growth of the Geobacter nor is sodium fumarate It is also encouraging to know substitutions with non lab grade materials can be done with promising results equivalent to those done with the standard ATCC media The results of this experiment also led directly to the next step of experimentation total substitution Bacteria Kinetics Experiment Experimental Set Up A key factor in the efficiency of the MFC is how long the bacteria will grow and how fast they will consume the food given Also temperature has a strong influence on the growth of bacteria and the specific effects are important to understand to predict the robustness of the cell Knowing these allows prediction of total MFC life and prediction of how often the MFC will need refilling for maintaining maximum growth and power Typically a batch reactor containing bacteria follows a well established bacterial growth curve as shown in Figure A2 There is a lag phase period where growth a
37. eees 21 5 3 1 RE 21 5 3 2 Eesen 24 5 3 3 eegene eege 26 534 Feed Syst m siisii reenen iri auton snout E E E A a iNe a E E 26 5 3 0 Proten Exchange Membranes ege ed Griet eege Gages 29 5 4 Eenelter ebe 30 e SE EE 31 6 1 Current Desi DE EE 31 6 2 Achieving HE ee 31 6 2 1 Sustama ME 31 E EE 32 6 2 3 POCO E 32 02A TPO EE 32 6 2 5 Power Re E 33 Recommendations for Future Improvement a c iccccd cece dthedcesesadessved tocoadsedessaratenecsdicendiesccacedes 33 eege Eeer ee 36 References Bib E E 37 Table of Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Fall semester Gantt chart scccsesi onsassdanseecssiacsaussaacsadwanes lt a csuassuacvnnncdes sbeageawelacsctusens 10 Final Prototype C8100 oefegee eege onsa aeei E E a ten SPREA C ASPAR 21 Injection apparatus Close Wp VieW ssssssssssesssssssssssssessssssssssssssesssesesseeeeeesessses 22 Anode chamber close up view 23 Cathode chamber close up view ccccccccccsssssseccccccecccasseeeccccceseeeuuueeseeeesceseeeauneeeess 24 Prototype Volta pe Output EE 30 Table of Tables Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 Actual Prototype Dudeet a a a a E a a E E 11 Full Cost Theoretical Prototype Budget 12 Estimated Production Unit Materials Coste 12 Bacterial Species Decision Table 19 Medias Rep seu adress Ed Ee 20 Cell Casing Decisions Matrix aslenn sooth ocd ees e
38. electrical production for five days 6 Conclusions 6 1 Current Design The final MFC prototype was successful in producing a maximum voltage of 666 mV with a sustained voltage of 650 mV over a 979 KQ resistance yielding a power of about 0 5 uW These preliminary results are projected to remain steady as the bacteria continue to thrive as the MFC is in operation A three chamber design was implemented an anode chamber cathode chamber and media storage chamber Inexpensive materials such as graphite for electrodes and PVC for the casing material were used to decrease cost to the project The feed media was experimentally simplified into a mixture of baking soda vinegar table salt ammonium chloride and sodium phosphate 6 2 Achieving Objectives 6 2 1 Sustainability The objective was to generate sustainable electrical energy BioVolt s MFC accomplishes this objective by generating power without the environmentally harmful and hazardous materials conventional batteries are composed of The organic wastes produced by the MFC are the waste products of the bacteria breaking down the feed solution and consists of carbon dioxide unconsumed media and water The waste contains many nutritional components needed by plants and could be used for watering a garden BioVolt s MFC contains microorganisms that reproduce and can produce power as long as there is a supply of fresh nutrients to the cell BioVolt s MFC is designed to be re
39. eria in Absorbance Units Figure A6 Prediction of Logarithmic Growth Rate In order to extrapolate beyond an environment containing 5 mL media of nutrients the absorbance must be converted to a concentration of cells This is done using Beer s Law Abs CeL where Abs the absorbance is equal to the concentration in molarity multiplied by the extinction coefficient e of the bacteria multiplied by the length Z of the sample the beam of the Spec20 passes through In this case and extinction coefficient was estimated to be approximately 30 000 M 1cm This was projected as Geobacter is similar to E coli and an average E coli extinction coefficient is in the upper 20 000 through 40 000 Mcm The diameter of the Balsh tube was 1 5 cm A main concern that propagated error is in the measuring of the bacteria once it began to form a bio film When using the UV Vis the measurement is taken at a specific A10 point in the tube If a clump of bacteria in a bio film were to cross the path of the light the absorbance of the clump would be taken However if no clump were to pass and only free floating bacteria were to pass through the measuring area a much smaller absorbance would be displayed Therefore the absorbance measurements later on in the experiment begin to increasing vary as some measurements are taken of clumps and some of suspended single microbes Kinetics Data Kinetics Experiment Results for tube 2
40. fuel cells A promising technology for wastewater treatment and bioenergy Biotechnology Advances 25 464 482 Dumas C Basseguy R amp Bergel A 2008 Microbial electrocatalysis with Geobacter sulfurreducens biofilm on stainless steel cathodes Electrochimica Acta 53 2494 2500 EHSO 2009 11 16 Battery Disposal Guide for Households Retrieved from Environment Health and Safety Online http www ehso com ehshome batteries php types lt May 11 2010 gt El Jalil M Faid M E Elyachioui M 2001 A biotechnological process for treatment and recycling poultry wastes manure as a feed ingredient Biomass and Bioenergy 21 301 309 Kim B C Postier B L DiDonato R J Chaudhuri S K Nevin K P amp Lovley D R 2008 Insights into genes involved in electricity generation in Geobacter sulfurreducens via whole genome microarray analysis of the OmcF deficient mutant Bioelectrochemistry 73 70 75 Li H Feng Y Zou X amp Luo X 2009 Study on microbial reduction of vanadium metallurgical waste water Hydrometallurgy 99 13 17 Rabaey K amp Verstraete W 2005 Microbial fuel cells novel biotechnology for energy generation TRENDS in Biotechnology 23 6 291 298 San Ka Ya Bioreactors in Biochemical and Metabolic Engineering Ed Nic Leipzig Rice University 15 Sept 2004 Web www bioc rice edu lt 11 May 2010 gt Sony Develops Bio Battery Generating Electricity from Su
41. g screws and bolts LED stands for light emitting diode A highly efficient form of lighting load the device or object to be powered media see bacterial media media storage chamber chamber in the MFC V1 for storing media before it is pumped into the anode MFC see microbial fuel cell MFC V1 the microbial fuel cell you own microbial fuel cell a type of fuel cell which uses the metabolism of bacteria to create electrical current non iodized table salt an ingredient in the media sodium phosphate an ingredient in the buffer solution and media solution table salt see non iodized table salt white vinegar an ingredient in the media 15
42. g to loosen the biofilm of bacteria formed on the bottom of the tube Also do this step quickly to minimize bacteria exposure to air 3 Centrifuge tube on 3000 rpm for 20 30 minutes 4 Bacteria should be visible as a small pellet on the bottom Discard all but 1 mL of media from the centrifuge tube attempting not to disturb the pellet 5 Add 0 27 mL of 75 glycerol to milliliter of solution Shake well 6 Transfer bacteria media glycerol solution into sterile cryotube using sterile pipet 7 Cap cryotube and store in 80 C freezer Bacteria disposal This procedure was followed for the disposal of all bacteria 1 Autoclave old bacteria on program Liquid20 2 Remove metal capping 3 Remove rubber stopper and place in biomaterial trash 4 Dump sterile contents in drain Clean tubes as usual Appendix D ATCC Media Recipe ICH TE 1 5g Na H2 POA ieser E EEE E E ERREEN 0 6 g e NIE 0 1 g IN HICOB stesbiegegeie tits A AET eineziceedbeaisass 2 5 Sodium acetate 0 82 g Sodium fumarate Dlter sterized eerren 8 0 g Wolfe s Vitamin Solution see below 10 0 ml Modified Wolfe s Minerals see below 10 0 ml Distilled water D ser sciccssscesere vescveeviesscceerecaclavacteebesvencestnsmiaieeves 1 0 L Prepare and dispense medium without fumarate anaerobically under an atmosphere of 80 N2 20 CO2 Autoclave at 121C for 15 minutes Add fumarate from a filter sterilized nitrogen sparged stock solution prior to inoculation
43. gar Physorg com 23 Aug 2007 Web http www physorg com news107101014 html lt 11 May 2010 gt Trinh N T Park J H amp Kim B W 2009 Increased generation of electricity in a microbial fuel cell using Geobacter sulfurreducens Korean J Chem Eng 26 748 753 37 Appendix Table of Contents Appendix A Research Prototype visa casiiuihingsdsseatutvcatnaascnada wants iuscliiewaiaiesieeeuendueiad eats A2 Appendix B Bacteria and Media Testing and Oppmzaton A4 Media Ingredient Substitution Experiment cccccccesccscesessesecseeseeeceaeeecseseeceeceeeeeceeseessesaeeeseesaees A4 Experim ntal Set EE A4 H aa a E E E e E A5 Eon ate LOSILO a EESE E A T T E a waiesaenelanet ame atentataeaas A5 Bacteria Kinetics Experiment E A5 Experimental Set EE A5 E EE A7 EE A9 Ki ti s Data ysis ion E i EE TOTEE EEEE whee onstuaces A11 Media Ingredient Omission Keperment A14 Experimental Set U Pirisen iee e a r Ea AE EE EES EAE EEE EEA A14 Er EE e A14 KEREN A14 EE ee A15 Exp rimental Set e EE A15 E E A15 Eeer A15 Appendix C Basic procedures for handling bacteria ccccscessescseeeeeeececeeecseeseeseseeeeseeaeeees A16 Appendix D ATCC Media EN A19 Appendix E MSDS Ammonium Chlorde ccceesessescsssescseeeecsseaeseessecaeeessseeecnesesaesaesaseeenees A21 Appendix F MSDS Sodium Phosphate Monobasic Monoblvdrate A22 Appendix G Users Manual EE AError Bookmark not defined Appendix A Research
44. ge lights recharge battery operated medical equipment cameras emergency cellular phones etc 6 1 1 2 Resources Limited resources are available for the construction and maintenance of the MFC in the area of projected use Since the projected use of the MFC is in rural and undeveloped areas designing a prototype while maintaining a low cost will result in a much broader impact The materials for building MFCs should be readily available or easily obtained and the feed to the cell must be inexpensive and simple to construct 5 1 2 Design Norms 5 1 2 1 Stewardship This project is based on BioVolt s commitment to use natural resources to create sustainable earth friendly energy for use in areas where energy is not readily or economically available In today s growing energy crisis carbon neutral sustainable and cost effective energy production is highly prized Development of alternatives like MFCs is the key to preserving the environment and weaning this technological age off burning coal Similarly it is the duty of Christians to use the resources given by God in a way that is pleasing efficient and resourceful Wastefulness and irresponsibility in daily lifestyles are not feasible for the long term or a portrayal of good stewardship By harnessing a naturally occurring process and using it to produce sustainable energy Team BioVolt demonstrates a renewable source of electricity Additionally good stewardship encourages the desig
45. h relative purity from a general supermarket Specifically sodium bicarbonate is purchasable in the form of normal baking soda and sodium acetate is more commonly known as vinegar A third substitution to be tested is the possibility of using common table salt sodium chloride instead of the recipe s potassium chloride The necessity of potassium in the growth of the bacteria is not known and must be experimentally determined Appropriate substitutions for lab grade ammonium chloride and dibasic sodium phosphate were not found but each of these components is inexpensive Also another ingredient to test was the necessity of addition of sodium fumarate to the media after autoclave sterilization It s noted that the addition of sodium fumarate is to act as an electron acceptor in the media Kim et al 71 Whether or not this is essential for short term growth was to be determined experimentally The substitution ingredients were purchased from Meijer and Aldi supermarkets Morton salt was used for the sodium chloride white distilled vinegar at 5 acidity was used for sodium acetate and Arm amp Hammer pure baking soda was used for the sodium bicarbonate Using the specified amounts in the ATCC recipe four solutions were made up The first was the control media which followed ATCC specifications The second media followed all ATCC specifications but substituted with Morton salt instead of potassium chloride The third media was substituted w
46. he immiscible liquid design does not adequately meet this design criterion Both the syringe design and the pump system design have the potential of being reliable but the syringe system has the need for syringe needles These can break or become dirty which could cause the feed system to fail All three design choices are very low cost so all options performed very well in this category The syringe system necessitates the purchase of replacement syringes and needles so it has a slightly higher cost system For these reasons summarized in Table 7 an injection pump system was implemented in the final design prototype Table 7 Cell Feed System Decision Matrix Gatien Category Immiscible Liquid Pump Pump Syringe Syringe gory Weight Liquid Subscore System Subscore Injection Subscore Isolation From 10 9 0 9 8 0 8 9 0 9 Oxygen Isolation From 10 8 0 8 10 1 10 1 Bacteria E 25 6 1 5 9 2 25 7 1 75 EE 15 7 1 05 9 1 35 10 1 5 Reliability 25 8 2 9 2 25 8 2 Cost 15 10 1 5 10 1 5 9 1 35 e 100 7 75 9 15 8 5 5 3 5 Proton Exchange Membrane As the most influential design aspect that affects the cell performance the proton exchange membrane PEM was chosen very carefully A PEM was chosen for the final prototype based on evaluation of each of the possible options against the following criteria e Performance The most important factor is performance the performance of th
47. in it e Reliability The feed system must be reliable so that its performance does not negatively interfere with the overall performance of the MFC e Cost To conserve the resources of the customer it is important that the feed system be as inexpensive as possible The three feed system options a syringe injection a pump system and using an immiscible liquid layer all provide adequate isolation from atmospheric oxygen The syringe feed system and the immiscible liquid would protect the bacteria from oxygen better than the pump system However the small exposure to oxygen which each of these options would give is negligible To effectively protect the MFC against outside bacterial species all three of these design choices must be slightly modified One effective way of keeping out bacteria would be filtering all incoming feed solutions This would be simple to do require inexpensive and widely available filters and be easy to integrate into all three of the design options In this way all three of the potential options rank equally well as they all use the same basic method for filtering It would however be easier and less prone to error to integrate a filter into a pump system or a syringe feed system as the filters can be added in line For this reason these systems both would be slightly better choices The pump system and the use of an immiscible liquid both would be fairly easy to use A pump system would require the user to
48. injection rate is 5 pumps per day to maintain monthly or when it appears very cloudy Drain the old buffer out of adequate food levels The bacteria can survive up to one week the cathode drain by unscrewing the drain at the bottom of the without food before showing any adverse effects If left unattended cathode chamber using the supplied hex key Part 018 When the for a number of days inject all food which had been missed in chamber is empty replace the cathode drain Prepare new buffer addition to food for the current day i e 10 pumps if 1 day missed 25 following the recipe outlined in 7 4 BUFFER RECIPE Fill the cathode pumps if 4 days missed chamber with buffer halfway up the neck of the fill cap to the fill line 12 Verify that the cathode buffer is not cloudy If it is follow the recipe outlined in 7 2 BUFFER RECIPE Remove the cathode fill cap Part 017 and leave the cap off whenever possible re 9 TROUBLESHOOTING 7 4 DISCARDING WASTE Discard all waste from the cell away from all water sources Problem The injection pump is very difficult to press or injects no fluid especially drinking water Cell waste may be used for watering plants Solution The bacterial filter may be blocked Replace the filter or crops Problem The injection pump injects only air Solution There may not be enough media in the media storage chamber Check the level indicator and add media as necessary 8 MAINTENANCE 8 1 FILTER REPLACEMENT Problem
49. ionality of the product and are able to maintain and use the product to its full potential Transparency through organization ties in with the Christian perspective on trust people will trust a technology that they understand The general public should be able to easily understand the operation and function of this form of energy production This level of understanding will encourage public awareness and stimulate interest in the design and ultimately the technology itself Furthermore if the MFC is to be in the intended locations it must have simple intuitive operating procedures that require little or no biological expertise This means the design should be basic enough so troubleshooting by the general public is possible If this is not possible MFCs will be an alternative energy only available to the scientifically educated public not the desired users 6 1 2 4 Integrity Integrity has been a cornerstone for BioVolt over the course of the design process The gathered research and assistance of others have been given due credit In the lab multiple experiments were performed to ensure reproducibility and no lab work or record has been falsified Ifthe design procedure had not progressed with integrity the final product could have been faulty harmful or misleading All challenges and failures have been addressed in the report so as not to give the reader false impressions of success or incorrect information 6 1 2 5 Cultural Approp
50. ith baking soda instead of sodium bicarbonate and the fourth used vinegar as a substitute for sodium acetate To measure the vinegar the solution was made up and then brought down to a pH of about 7 0 using the vinegar The pH of each solution was observed and verified to be 7 0 0 8 One quarter liter of each media was constructed using nanopure water followed by filter sterilization process described in Appendix X Using 10 clean Balsch tubes each substituted media was put into two tubes but with four of the tubes filled with the control media After being sterilized appropriately vitamins and minerals were added to each of the tubes and sodium fumarate was added to all but two of the tubes filled with control media After inoculating with bacteria the tubes were placed in the 30 C incubator and grown for 10 days Results After the 10 day growth period the tubes were inspected qualitatively for growth The results are as follows in Table Table A1 Substitution Experiment Results Tube Growth appearance 1 Control Very good growth visible film 2 Control Excellent growth suspended filmy substance 3 Control media minus sodium fumarate Ok growth some floating clumps visible 4 Control media minus sodium fumarate Very good growth film covering bottom 5 Media substituted with salt Ok growth some floating clumps visible 6 Media substituted with salt Excellent growth suspend
51. lso responsible for prototype conceptualization and design utilizing his expertise in Inventor throughout the designing process Jeff also participated in final design assembly He was also in charge of visual deliverables such as the user manual and various process flow diagrams Diane Esquivel was responsible for set up of the appropriate feedstock for the MFC She also learned the variety of biological protocols and procedures used for growing the bacteria needed for the cell and aided in the bacterial experiments Diane was responsible for keeping track of the cost of used and needed materials as well as the overall budget of the project and the potential business plan marketing analysis Andrew Huizenga was responsible for the ordering and acquisition of all materials needed for the final prototype as well as all research prototypes used in the experimentation process He was the primary contact with Membranes International and made internal design decisions and selections Andrew was in charge of prototype construction for both the final prototype and the research prototypes 3 2 Schedule Because this project was quite expansive Gantt charts were used to properly budget the necessary time to complete the various tasks Through careful time management the project progressed in an efficient and timely manner The Gantt charts are broken down by semester and display major tasks relevant to the design and construction process Week
52. lt with the laboratory space and materials which were crucial to the success of this project Without Professor Wertz s help and support BioVolt would not have had the knowledge or materials to complete this project Ben Johnson Lab Assistant Ben Johnson taught the team many crucial laboratory techniques and procedures which were instrumental in the success of the project Professor Jeremy VanAntwerp Academic Consultant Professor VanAntwerp provided the team with the fundamental idea on which this project is based 9 References Bibliography AATC n d The Global Biosource Center Retrieved from American Type Culture Collection www atcc org lt May 11 2010 gt Amherst U o 2009 Retrieved from Geobacter Project http geobacter org lt January 20 2010 gt Behera M Jana P S amp Ghangrekar M 2010 Performance evaluation of low cost microbial fuel cell fabricated using earthen pot with biotic and abiotic cathode Bioresource Technology 101 1183 1189 Chung K amp Okabe S 2009 Continuous power generation and microbial community structure of the anode biofilms in a three stage microbial fuel cell system Applied Microbial Biotechnology 83 965 977 Dewan A Donovan C Heo D amp Beyenal H 2010 Evaluating the performance of microbial fuel cells powering electronic devices Journal of Power Sources 195 90 96 Du Z Li H amp Gu T 2007 A state of the art review on microbial
53. ly meetings were utilized to track progress discuss ideas and solve issues associated with the design process BOAON OE po2 q 4 po2aa tT Define Team Project Defined General Research Project Objectives PPFS Outline Meet Mr Remelts Devotions Research Bacteria Research growth factors Research Anode and Cathode Project Poster Project Website Oral Presentation 1 Meet with Biology Department Individual sections for PPFS Compiling for PPFS draft Meeting with Mr Spoelhof PPFS draft Revised Website Oral Presentation 2 Final PPFS Preliminary Design Memo OT 994 T Research Prepare final report Testing experiment 1 Testing experiment 2 Testing experiment 3 OT 494 8 Figure 1 Fall semester Gantt chart 5 Jan 10 8 Jan 10 12 Jan 10 15 Jan 10 19 Jan 10 22 Jan 10 26 Jan 10 Figure 2 Interim Gantt chart PT 4eIN ST PT 4eIN 7Z PT 4eIN 6Z PT 424 ST PT qe4 zz OT eW T PT eW 8 OT dy s pt sdy zT DT udy 6T DT 1dy 97 jot Aew PT AeW OT Preparation of final report Prepare presentation 3 Presentation 3 Prepare presentation 4 Presentation 4 Final report Outline Meet with Mr Spoelhof Writing of Individual sections Compiling for Final draft Document Revision CEAC Review Draft due Final Copy Prepare Final Presentation Final Presentation Sr Design
54. mber Fill the anode chamber Part 002 half full with media by removing the anode fill plug Part 015 Add provided bacteria to cell Fill the rest of the chamber with media trying to leave as little air space as possible Replace fill plug Fill the media storage chamber with the remaining media Inject media using the injection pump until some volume of waste is removed with each pump Once the anode chamber is full follow the instructions outlined in 7 2 BUFFER RECIPE Make one batch of buffer and add it to the cathode cell Part 003 Leave the cathode fill cap Part 017 off unless transporting the cell The MFC is now ready to begin the bacterial growth phase 6 2 STARTING BACTERIAL GROWTH Initial bacterial growth takes 12 days Promote bacterial growth by connecting the anode terminal Part 011 to the cathode terminal Part 016 using a wire Allow the cell to stand for 7 days MECHT User Manual BioVolt without feeding After 7 days inject 30 pumps of new media Allow cell to stand for another 5 days without feeding After 5 days remove the wire connecting the terminals The MFC is now fully operational Attach the positive and negative terminals Part 016 and Part 011 to the desired load and begin operation under the procedure outlined in 7 GENERAL OPERATION 11 7 GENERAL OPERATION 7 1 MEDIA RECIPE For the media to serve as an acceptable food source for the bacteria it must be made following these instructi
55. move the fill cap Figure 4 Anode chamber close up view Anode Electrodes Eight electrodes composed of graphite are wired in parallel to a single terminal in the Anode Chamber The microorganisms form a biofilm upon the electrodes providing the electrons needed to produce electricity Proton Exchange Membrane The Proton Exchange Membrane is made from Ultrex CMI 7000 Cation Exchange Membrane and separates the Anode Chamber from the Cathode Chamber The membrane is the key to the functionality of the cell since it is the membrane that forces the electrons to run through external wiring load in order to get to the Cathode Chamber Figure 5 Cathode chamber close up view Cathode Electrodes There are four cathode electrodes composed of graphite that are wired in parallel and connected to a single cathode terminal The reduction of oxygen occurs on the surface of these electrodes completing the electrical circuit between the Anode and Cathode Chambers 5 3 2 Casing Material The prototype casing material was selected on the basis of several key design factors e Availability In keeping the design norm of stewardship it is important that the material be widely available e Cost To conserve the resources of the customer it is important that the casing be as inexpensive as possible e Opaquacity The material must be opaque in order to block UV light from reaching the bacteria e Durability The material
56. must be durable in order to handle the possibility of dropping the potentially harsh conditions where the MFC is to be deployed and the constant exposure to the bacteria and feed solution e Workability The material must be simple to work with and require only limited labor and assembly Based on these criteria two materials were investigated for possible use Both steel and PVC are widely available so both scored very high in this category This was a highly rated decision factor because of BioVolt s desire to market this device in rural areas without access to many specialty materials These two materials also are very inexpensive which is in keeping with the design norm of stewardship however when comparing the two PVC is significantly less expensive than steel Because both materials block 100 of incoming UV light both were valid options for construction the cell casing The durability of PVC is higher since the cell would constantly be exposed to the bacterial feed solution and the phosphate buffer in the anode and cathode respectively This constant exposure to a salt solution would cause the steel to rust at an increased rate unless the cell was made out of an expensive metal such as copper or a high grade stainless steel and in following the design norm of stewardship the extra cost associated with either of these options was deemed to be unacceptable Because both materials are easy to work with opaque and widely avail
57. n of bacteria with optimal growth conditions and an electron acceptor an electrical current can be generated Microbial fuel cells sometimes also referred to as bio batteries take advantage of this process and have become an area of intense research in the field of alternative energy BioVolt set out to replicate and build on the research in the area of MFCs by creating a prototype which would demonstrate MFC s potential for low maintenance operation use a bacterial feed comprised of ingredients easily attainable by the customer and provide electricity over an extended time period Since MFC power output is relatively low BioVolt s intended customers are people living and or working in rural areas that do not have readily available access to conventional electrical grids People living in these areas would benefit from a very low cost device that could deliver enough electricity to power low voltage lights and or recharge batteries for medical or other devices 2 Problem Specification 2 1 Project Scope The scope of this project is to take ideas being generated in current research on microbial fuel cells and apply them to produce a fully functional prototype that could potentially be used commercially This project focuses on engineering design and optimization of the fuel cells functional unit while meeting specified objectives It is assumed that any power regulation necessary to accomplish a specific task i e charging a bat
58. n to be as cost effective as possible because being a good steward also pertains to the efficient use of resources such as capital Creating a cost effective MFC also encourages broader application and allows this sustainable technology to become more widely deployed 5 1 2 2 Trust Gaining the trust of any customer who would purchase and operate a microbial fuel cell is an important design norm that impacted the prototype design of this project Having a reliable power source is crucial especially when it is the only source of power available as the MFC would be for nearly all of the projected customers Unexpected failures could result in lost time expensive repairs frustration by the consumer and if being used to charge medical equipment possible physical harm If the MFC is not dependable potential clients will not invest in the technology rendering the MFC ineffective in fulfilling the customer s energy needs It is also never within a Christian perspective to produce an unreliable or untrustworthy product A Christian commitment encourages a quality result 5 1 2 3 Design Transparency The design process of this microbial fuel cell was carefully documented This documentation makes the expressed results reproducible from the documented research and experiments so further testing and optimization could build upon this research Aside from replication this design needed to be transparent so that users can understand the funct
59. nd reproduction of the cells are just beginning so initial growth is small However after A5 accustomed to the environment if there are sufficient or excess nutrients the bacteria will go through logarithmic growth Reproduction will occur at an exponential rate At some point in a batch the nutrients and space available will be exhausted and a stationary phase will be held by the bacteria Here while there is still reproduction it only occurs approximately equal with the death rate Finally when all the nutrients have been consumed the bacteria will enter the death phase unless there is a change in the environment The goal for optimum MFC performance is to have the user introduce fresh media containing nutrients in the latter part of the log phase This kinetic experiment was prepared in order to estimate these time parameters Six tubes of standard ATCC media were prepared together using the same techniques and procedures Only 5 mL of media were put in each tube Of these six tubes four of them were inoculated at the same time Two of the inoculated tubes were kept in the cupboard with one blank tube and two were kept in a 30 C incubator also with one blank tube Using the UV Vis Spec20 spectrophotometer the absorbance of the contents of the tube was monitored over the next 7 days at a wavelength of 600 nm This is a typical wavelength used to measure the growth of various bacteria and monitored at a similar wavelength 620
60. o be at the ATCC suggested amounts or ingredients in the media A15 Appendix C Basic procedures for handling bacteria Tubing the Anaerobic Media The following procedure was followed to ensure optimal bacterial growth Leaving the media on vacuum removes dissolved oxygen from the solution Flushing the media and tubes with nitrogen reduces the exposure to air as well as attempts to create an air free anaerobic environment within the test tube 1 Pour excess of the desired media amount into a vacuum Erlenmeyer flask Place stopper in position and place the media in a sterile environment with a vacuum system Vacuum the media for 20 30 minutes 2 Quickly transfer media from vacuum flask to an Erlenmeyer flask under a flow of nitrogen Insert stopper into flask and flush with nitrogen for two minutes 3 While flushing the media flush a clean Balsh tube with nitrogen for two minutes as well 4 Using a sterile pipet transfer 5 mL of media into Balsh tube Be sure to minimize the time any of the media is exposed to air 5 Once the media is in the Balsh tube flush the tube again with nitrogen for two minutes 6 Insert rubber stopper fully cap with metal pull back top and crimp with a metal fitting 7 Autoclave using the Liquid20 program Prepping for bacteria This procedure was followed in the early stages of testing to ensure initial bacterial growth and culturing The desired final design however excludes the ad
61. onclusion It can be concluded that phosphates and ammonium chloride are essential for the growth of the bacteria This is not surprising as all living organisms require phosphates for DNA and ATP production Nitrogen is also a component that catalyses growth on a bacterial level Because of this it will be necessary to include phosphate and ammonium chloride in a package as these components are not readily available in remote places However these are not expensive nor are they restricted or hazardous materials Robustness Experimental Set Up As the media will be made and mixed in non laboratory setting with non laboratory measuring devices it is very likely that some measurement error will occur in the media It is important to understand if these types of errors will affect the health and growth of the bacteria For example the addition of too much 5 acidity vinegar about 1 mL or more would affect the pH of the solution to the point that the bacteria could not survive in such acidic conditions Ammonium chloride is also acidic with a pH of 5 5 Optimum growth pH is about 6 8 7 0 So the addition of too much vinegar would result in cell death possibly killing all the bacteria in the cell But imperfect media in salt is not as detrimental In order to prevent bacteria stress and death with other components a robustness test was designed Since the result of too much of vinegar and ammonium chloride is predictable they were not tested
62. ons 1 Heat 1 liter of water to a boil 2 Let water cool to room temperature 3 Add 1 4 teaspoon Ammonium Chloride 1 8 teaspoon Sodium Phosphate Monobasic 1 2 teaspoon Baking Soda 1 teaspoon White Vinegar A pinch Non lodized Salt 4 Mix until all ingredients are dissolved 7 2 BUFFER RECIPE The cathode buffer is prepared as the following recipe 1 Measure 2 liters of water 2 Add 3 8 teaspoons of Dibasic Sodium Phosphate MFC V1 User Manual BioVolt MECHT User Manual BioVolt The bacterial filter Part 009 keeps other species of ae PEDINE INE E bacteria out of the cell and must be replaced at the beginning of each month This is done by removing the media storage chamber end cap Verify that the media in the media storage chamber part of the cell Part 010 Removal of the cap will expose three hoses 001 is not cloudy Cloudy media indicates that it has been as well as the filter mechanism Pull the hose off both sides of the contaminated by other bacteria If media is cloudy discard immediately Make sure the level indicator Part 005 on the side of the cell shows sufficient media in the media storage chamber used filter Insert the new filter into the hose and replace end cap Pump the media from the media storage chamber into the anode chamber Part 002 where the bacteria is growing using the 8 2 BUFFER REPLACEMENT injection pump Part 006 The buffer in the cathode chamber should be replaced The optimal
63. ons as a PEM would but also is very inexpensive and easy to produce The downside to a salt bridge is that it must always remain wet fouls relatively quickly and is not nearly as efficient as a real PEM is Since the experimental prototypes need only to be compared to each other using an inefficient salt bridge does not affect the ability to compare different variables being tested The salt bridge see appendix X for the recipe is used only once before being replaced Anode Chamber The Anode Chamber contains the Anode Electrode immersed in inoculated media This chamber is nitrogen flushed and completely sealed off from the outside environment by means of a threaded plug Anode Electrode The Anode Electrode is composed of graphite and is the location where the bio film is formed by the microorganisms Appendix B Bacteria and Media Testing and Optimization Media Ingredient Substitution Experiment Experimental Set Up Initial experiments were done to test the possibility of substituting supermarket available ingredients in the media Having available ingredients is important to the cultural appropriateness of the project if the materials for the feed are not easily attainable upkeep of the MFC would be expensive and difficult The control media is the standard ATCC recipe attached in Appendix D with five main ingredients not including the vitamins and minerals Of these five core components two can be easily obtained wit
64. riateness Cultural appropriateness is crucial for the successful implementation of the MFC If the MFC does not meet the needs of the customer then the technology will not be adopted This means that part of the design process of the MFC focused on adapting the technology to the current culture and making as few additional demands from the users as possible This applies to the materials chosen to produce this MFC as well as the design as a whole If the components of the cell are not readily available or the ingredients of the media are expensive and uncommon upkeep use and implementation of the MFC becomes non feasible Only by creating a culturally appropriate product can BioVolt begin to address the energy needs in developing areas 5 1 3 Environment Safety and Health 6 1 8 1 Environment A key aspect of the MFC design is the environmentally friendly nature of the energy source The main product of bacterial digestion is carbon dioxide and the waste from the anode chamber is composed primarily of unused nutrient feed which contains acetate table salt baking soda ammonium chloride and sodium phosphate in water These components are not harmful to the environment and are suitable for watering plants The MFC is designed to be refilled and reused but if a non functional MFC is to be disposed of it is constructed out of 100 recyclable materials Bacterial disposal should be handled with care The bacteria species is non toxic
65. rototype is Geobacter sulfurreducens Through a review of the literature BioVolt determined that this species of bacteria is a strong candidate for use in an MFC because it can be grown in a simple nutrient media composed primarily of acetate The media used in the final prototype is a simplified variation of the lab grade media supplied for bacterial growth This media is composed of water baking soda vinegar table salt ammonium chloride and sodium phosphate Much of this media is constructed from common household items however small quantities of the lab grade chemicals ammonium chloride and sodium phosphate are also needed 5 2 2 Bacteria Culturing Through research into the performance of many different bacterial species shown in previous research the bacterial selection was narrowed down to three species Geobacter sulfurreducens GSR Geobacter metallireducens GMR and Rhodoferax ferrireducens RFR These species were researched and evaluated based on five criteria price power production accessibility caring and the required media Table 4 summarizes how the three different species were compared and evaluated Table 4 Bacterial Species Decision Table Bacterial Species Decision Table Weight GSR GMR RFR Price 20 7 7 7 Power 35 8 7 5 Accessibility 5 8 9 6 Caring 15 8 8 8 Feed 25 6 6 4 Total 730 700 565 The most influential factor of the bacterial species selection
66. tery or powering a low power device can be purchased separately and simply attached to the functional unit 2 2 Project Objectives 2 2 1 Sustainability This project is intended to demonstrate the creation of an environmentally friendly form of energy production To accomplish this objective the design must produce a minimal amount of waste during its operation and disposal 2 2 2 Size In order to fulfill the design considerations for the intended customers the working prototype must be transportable from one location to another Therefore the size and weight of the prototype must promote reasonable portability 2 2 3 Feed The feed or media used under research conditions for microbial fuel cells is typically a complicated solution of laboratory chemicals in precise concentrations In order to produce a prototype that promotes use in the intended market BioVolt must design a feed media formulation that is comparably effective as the laboratory media is inexpensive and can be constructed from readily available components using common measuring utencils 2 2 4 Lifetime The design of a final prototype must take into consideration means by which to maximize the functional lifetime of the MFC The prototype MFC should be able to last for one year with minimal user intervention or maintenance 2 2 5 Power Output The goal set forth by this project is to build upon existing research and improve upon the accomplishments p
67. the traditional two chamber proton exchange MFC but other designs such as a single chambered air cathode MFC show great promise Commercially MFCs are being researched and prototypes are being constructed that remove the living organism from the design completely Sony Corp unveiled a prototype that incorporates only the enzymes necessary to digest the feed Physorg com eliminating the inherent drawbacks of working with a live bacterial culture 8 Acknowledgements BioVolt would like to specially thank all the many people who have aided us in this project and contributed to its success throughout the academic year Professor Aubrey Sykes Team mentor Professor Sykes guided team BioVolt throughout both semesters of the project pointing out potential problems offering up potential solutions to some of the problems encountered and sharing his project management experience with the team Membranes International Donor Membranes International generously donated a large proton exchange membrane which was used in the final prototype Mr Chuck Spoelhof Industrial Mentor Mr Spoelhof helped to guide this project with his probing questions and realistic analysis of the progress made during the first semester of the project Mr Spoelhof helped the team work through several different difficult design decisions providing critical analysis and helpful ideas Professor John Wertz Biological Consultant Professor Wertz generously provided BioVo
68. tions The MFC V1 has been designed by BioVolt to operate with only limited maintenance for over 1 year It provides an environmentally friendly sustainable power source which can be used to fulfill a variety of small scale electrical needs MFC V1 User Manual BioVolt With the MFC V1 you can charge the battery on a medical device recharge your cell phone or run LED lights to light up your house Table of Contents 1 INTRODUCTION 2 INCLUDED WITH THE MFC V1 2 1 BACTERIA 2 2 FEED MATERIALS 2 3 PARTS AND TOOLS 2 4 WARRANTY 3 ENVIRONMENT HEALTH AND SAFETY 3 1 ENVIRONMENT 3 2 HEALTH 3 3 SAFETY 4 PRODUCT OVERVIEW 4 1 How IT WORKS 4 2 CELL LAYOUT 5 CARING FOR THE BACTERIA 5 1 HEALTH CONSIDERATIONS 5 2 NUTRIENTS 6 GETTING STARTED 6 1 INITIAL SETUP 6 2 STARTING BACTERIAL GROWTH 7 GENERAL OPERATION 7 1 MEDIA RECIPE 7 2 BUFFER RECIPE MECHT User Manual BioVolt 7 3 FEEDING THE BACTERIA 7 4 DISCARDING WASTE 8 MAINTENANCE 8 1 FILTER REPLACEMENT 8 2 BUFFER REPLACEMENT 9 TROUBLESHOOTING 10 GLOSSARY OF TERMS 2 1 INTRODUCTION The MFC V1 by BioVolt is a microbial fuel cell which has been designed to produce enough power to light low power LED lights and charge batteries for use in medical equipment emergency cellular telephones or other electronic devices A microbial fuel cell MFC is a battery which produces power using a specific species of bacteria This bacteria eats a specific food solution called the ba
69. to approximately 500 ml of water and adjust to pH 6 5 with KOH to dissolve the compound Bring volume to 1 0 L with remaining water and add remaining compounds one at a time Appendix E MSDS Ammonium Chloride Science Lab com Chemicals amp Laboratory Equipment Material Safety Data Sheet Ammonium chloride MSDS Section 1 Chemical Product and Company Identification Product Name Ammonium chloride Catalog Codes SLA3415 SLA1069 SLA2575 SLA4078 SLA1732 SLS3118 CAS 12125 02 9 RTECS BP4550000 TSCA TSCA 8 b inventory Ammonium chloride CH Not applicable Ammonium Munate Sal Ammonia Salmiac Chemical Name Ammonium Chloride Chemical Formula NH4C1 Potential Acute Health Effects Contact Information Sciencelab com Inc 14025 Smith Rd Houston Texas 77396 US Sales 1 800 901 7247 International Sales 1 281 441 4400 Order Online ScienceLab com CHEMTREC 24HR Emergency Telephone call 1 800 424 9300 International CHEMTREC call 1 703 527 3887 For non emergency assistance call 1 281 441 4400 Hazardous in case of eye contact imitant Slightly hazardous in case of skin contact irritant sensitizer of m ion of inhalat Potential Chronic Health Effects CARCINOGENIC EFFECTS Not available MUTAGENIC EFFECTS Not available TERATOGENIC EFFECTS Not available DEVELOPMENTAL TOXICITY Not available Repeated or prolonged exposure is not known to aggravate medical condition
70. ublished to date Since many other objectives have an effect on power output the project goal is to produce at least a comparable power output to the published data According to Rabaey and Verstraete in Microbial fuel cells Novel biotechnology tor energy generation a power output of 10 20 mW m of electrode surface area is obtainable for a prototype 3 Project Management 3 1 Work Breakdown Structure The project work has been distributed among the four chemical engineers in the team Each individual made a significant contribution to the project and tasks were divided so each team member s involvement was essential in the successful completion of the project All were responsible for completing their individual parts on time and for helping the other team members with their assignments when necessary Lindsay Arnold was responsible for the research involved in the project as well as assuring all tasks were completed on time She was in charge of the biological logistics of the MFC and learned the variety of biological protocols and procedures used for growing the bacteria needed for the cell She designed and performed media and kinetics experiments and analysis and optimized media for bacterial growth and cost efficiency Jeff Christians was responsible for the electrical concepts of the project which included selecting the anodes and cathodes necessary as well as all internal design decisions for the final prototype He was a
71. um chloride and sodium phosphate Since no readily accessible analogs for these salts could be found it was determined that BioVolt would market their MFC as a kit that includes a year s supply of these components along with the MFC casing and microbial culture 6 2 4 Lifetime The objective was to produce a prototype that maximizes the life of an MFC with minimal user intervention BioVolt accomplished this goal by designing an MFC that functions as a semi batch process The biological aspect of an MFC can theoretically last indefinitely given the cell conditions are maintained and the microbes are supplied with sufficient nutrients A semi batch process is simpler than a constant flow nutrient feed and lasts longer than a batch process because the media and its nutrients can be replenished This semi batch design requires a user to operate the pump bulb five times per day This provides enough nutrient turnover to sustain life 32 6 2 5 Power Output The objective was to produce a power output of 10 mW m or greater which would improve upon existing literature data BioVolt produced about 21 1 W m which is significantly less than the literature data While the output is not comparable to the literature data it was achieved without using a platinum catalyst and demonstrates a rugged non laboratory design that could be implemented commercially 7 Recommendations for Future Improvements The major drawback of BioVolt s prototype
72. urchased to mold the casings for each unit and either machines or a labor force would have to be in place to assemble each unit From a conservative estimate about 3 00 per unit will be added to cover operating costs One hurdle that needs to be investigated and overcome before BioVolt s MFC could become commercialized is the aspect of shipping the final kit including bacteria to the end customer Shipping microbiological cultures is a tightly regulated process both legally and logistically Most cultures need to be shipped cryogenically so as to reduce the chance of cell death by the time the package is delivered This is extremely costly reference Table 1 Shipping across borders also poses legal issues with customs Therefore BioVolt initially would plan to base productions in a location that is local and central to their targeted customers 5 Design 5 1 Design Considerations and Criteria 5 1 1 Projected Customers 6 1 1 1 Profile Because of the low initial cost low operating costs and low power output associated with an MFC BioVolt s main market is people who live or work in areas without access to conventional means of power production but still have need of small amounts of electrical power for applications such as low voltage lighting recharging batteries for medical devices For example BioVolt is targeting rural missions and rural health providers hoping to provide a much needed source of energy to power low volta
73. used meaning upon bacterial death the microorganisms and nutrient media can be replaced providing new life to the cell Furthermore the materials of construction of BioVolt s MFC are completely recyclable if the user ever decides to dispose of the cell in its entirety 6 2 2 Size The objective was to produce a semi portable design to comply with the culture of the area the MFC is intended to serve The final prototype cell is indeed portable with an overall size of two feet with a four inch diameter and weighing approximately fifteen pounds when all three chambers are completely full However the cell is designed to operate in a stationary position since the cathode chamber must remain open to the atmosphere during operation 6 2 3 Feed The objective was to produce a feedstock that provided the required nutritional needs of the bacteria but is inexpensive and also composed of readily available ingredients BioVolt met this objective by optimizing the feed required by the bacteria investigating replacement ingredients and determining to what degree of feed ingredient measurement errors resulted in adverse effects on the MFC The simplified formula is comprised of water baking soda vinegar table salt ammonium chloride and sodium phosphate all converted into easily measurable units such as teaspoons in order to simplify the construction of the feed media All of these ingredients are considered readily available except for ammoni

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