ENGINEERING 692 – SERVICE LEARNING IN HONDURAS: MONTANA DE LUZ
Water Supply Team
Final Documentation
March 17, 2012
Written by:
Amelia Quilon
Laura Reisenauer
Rayvion Sanford
Sarah Watzman
TABLE OF CONTENTS
BACKGROUND ....................................................................................................................................................... 4
Generator/Storage Capacity Increase ...................................................................................................................4
Biodigester ............................................................................................................................................................4
Tilapia Pond ..........................................................................................................................................................5
PARTICIPANTS ....................................................................................................................................................... 5
PROBLEM DEFINITION ........................................................................................................................................... 6
Generator/Storage Capacity Increase ...................................................................................................................6
Biodigester ............................................................................................................................................................8
Tilapia Pond ..........................................................................................................................................................8
STATEMENT OF OBJECTIVES .................................................................................................................................. 8
Generator/Storage Capacity Increase ...................................................................................................................8
Biodigester ..........................................................................................................................................................10
Tilapia Pond ........................................................................................................................................................10
COST ANALYSIS .................................................................................................................................................... 11
Generator/Storage Capacity Increase .................................................................................................................11
Biodigester ..........................................................................................................................................................11
Tilapia Pond ........................................................................................................................................................12
DETAILED PLAN OF ACTION ................................................................................................................................. 13
IMPLEMENTATION ............................................................................................................................................... 16
RESULTS AND OBJECTIVES ACHIEVED .................................................................................................................. 18
Generator/Storage Capacity Increase .................................................................................................................18
Biodigester ..........................................................................................................................................................19
Tilapia pond ........................................................................................................................................................25
FUTURE RECOMMENDATIONS ............................................................................................................................. 27
Generator/Storage Capacity Increase .................................................................................................................27
Biodigester ..........................................................................................................................................................28
Tilapia Pond ........................................................................................................................................................29
APPENDICES......................................................................................................................................................... 30
Appendix A: References.......................................................................................................................................31
Appendix B: Team Agreement ............................................................................................................................34
Appendix C: Pump Information ...........................................................................................................................36
Appendix D: E-Mail Correspondence With Staff..................................................................................................39
Appendix E: Biodigester and Compost Instruction Manual, English Version (Created from 2011 Biodigester
Team) ..................................................................................................................................................................48
Appendix F: Questions and Answers from MdL Staff (“Parking Lot”) .................................................................55
Appendix G: Bill of Materials...............................................................................................................................64
Appendix H: Biogas Production Analysis .............................................................................................................68
appendix I: Manure Procured Analysis ................................................................................................................71
Appendix J: Initialization Volumes Analysis ........................................................................................................73
Appendix K: Helpful Spanish Words and Phrases ................................................................................................76
BACKGROUND
GENERATOR/STORAGE CAPACITY INCREASE
Montana de Luz is an orphanage and community in south-central Honduras placed on top of a
hill. The orphanage supports children affected by HIV/AIDS and offers them a loving, caring,
family-like environment. Through projects developed by staff, supporters, and service teams,
Montana de Luz has grown to become nearly self-sustainable. Nevertheless, the orphanage
does rely on electricity from an outside power source, and this electricity is used to power the
water pump -- the start of Montana de Luz’s water distribution system. When electricity is lost,
the pump also loses power; therefore the orphanage is likely to run out of water. The team
assessed multiple solutions including a generator and increasing Montana de Luz’s water
storage capacity.
BIODIGESTER
Montana de Luz currently has a malfunctioning biodigester installed. A biodigester operates by
digesting organic waste and turning it into methane gas, which can then be burned to use to
power the orphanage’s appliances. The gases are formed from the breakdown of the organic
waste (called influent) in the air-tight dome section of the biodigester. The output of the
biodigester, called effluent, is nutrient-rich and extremely useful in farming or gardening.
More specifically, Montana de Luz has a fixed-dome biodigester. The influent is poured into a
pipe, travelling into the ground to the main chamber. The top of the main chamber is at
ground-level, and an air-tight door exists there to be used if looking inside the chamber
becomes necessary. The gas pipe comes from the top of the dome as well, and it travels to the
kitchen next to the chicken coop. The effluent comes out of the biodigester through a pipe
above ground.
Last year, a team investigated the reasons for the biodigester malfunctioning. Once on site, the
main cause was determined to be a clogged biodigester from too many solids being put inside
of it. Upon returning to Columbus, a submersible pump was purchased and sent to Montana de
Luz in order to remove the contents of the biodigester from its inner chamber and begin its
operation again.
TILAPIA POND
Several years ago, a tilapia pond was constructed at Montana de Luz that was intended to be
stocked with tilapia, a hardy fish that can live in varying conditions. The tilapia pond would
supply the orphanage with a stable source of protein to supplement the children’s diets and
create a marketing opportunity if enough fish were harvested to sell to nearby Hondurans.
Unfortunately, the tilapia pond at Montana de Luz was deemed a burden and was shut down
due to lack of training and sustainability as well as electric costs associated with continuously
running a pump to aerate the pond.
Last year, a team reinstated the tilapia pond by patching cracks in the foundation of the
structure and also making several changes to the construction of the system. The team decided
that the tilapia pond was too deep and thus decreased the level of the water. A more shallow
pond decreases the need to continuously aerate the pond, thus saving on electricity costs.
PARTICIPANTS
Amelia Quilon is a third-year student in Industrial and Systems Engineering. Amelia will be
primarily responsible for repairing the cracks in the tilapia pond and developing the rotational
schedule that Montana de Luz will use to schedule their harvesting.
Laura Reisenauer is a third-year student in Environmental Engineering. Laura will be primarily
responsible for repairing the cracks in the tilapia pond and evaluating Montana de Luz’s current
system capacity and training/knowledge about the tilapia pond.
Sarah Watzman is a third-year student in Mechanical Engineering. Sarah will be primarily
responsible for overseeing the removal of the biodigester’s contents and developing
appropriate training for Montana de Luz’s staff on how to use the biodigester properly.
Rayvion Sanford is a third-year student in Chemical Engineering. Rayvion will be primarily
responsible for overseeing the removal of the biodigester’s contents and creating instructional
posters that will document instructions on how to use and maintain the biodigester.
Overall, all team members will be involved with the physical labor associated with the
biodigester project and the documentation that will be completed throughout the trip.
However, each team member has a specific responsibility in order to ensure that all tasks are
completed efficiently and effectively.
PROBLEM DEFINITION
GENERATOR/STORAGE CAPACITY INCREASE
Currently, Montana de Luz retrieves water from a well about 100 feet lower in elevation than
the buildings of its campus. The well water is pumped up to the orphanage using an electric
pump, which distributes the water to the water storage tanks that feed the cistern by gravity.
When Montana de Luz has electricity, the lift pump fills the tanks according to the float sensor
as water is used throughout the day. Figure 1 contains a diagram displaying the water
distribution and supply system.
Figure 1: Schematic of Water System
However, when power is lost, the orphanage can only rely upon gravity and pressure
differences to receive water; therefore, once the tanks are emptied, Montana de Luz has no
water with which to drink, cook, or clean until power is restored. Montana de Luz can have
additional water shipped in on a truck. However, this is expensive and forces Montana de Luz to
be dependent upon an outside source for clean water. Therefore, the purpose of this project is
to find and implement a cost effective and sustainable way to reduce Montana de Luz’s costs
and reliance upon others for clean water when they have no electricity. However, as explained
later in the report, we chose not to pursue a solution because the costs were greater than the
benefits.
BIODIGESTER
Montana de Luz currently has a fixed dome biodigester installed on its campus. Some
documentation is available, but whether or not this documentation is for biodigesters in
general or this specific one is unclear. Additionally, no documentation on how to properly
operate or fix this particular biodigester exists.
That being said, the 2011 Biodigester Team’s report proved incredibly helpful in this project.
The team last year assessed the condition of the biodigester and concluded that it was clogged
from too high of a concentration of solids being added to the biodigester. To clean the
biodigester, the team sent a submersible solids pump to MdL; the pump is currently functioning
and being used for the tilapia pond but has not been used to clean the biodigester.
Additionally, through their research, the proper ratio of food waste to water was determined to
be 2:1.
TILAPIA POND
Since the team’s project in the last year, Montana de Luz has been able to harvest fish multiple
times throughout the year. Although the pond is still functional and operating smoothly, one
section of the pond still contains cracks in the foundation that need to be repaired. The team
also plans to install a rotational schedule so that the orphanage can harvest batches of tilapia
more frequently, thus increasing the yield per year of tilapia.
STATEMENT OF OBJECTIVES
GENERATOR/STORAGE CAPACITY INCREASE
The objectives for this project included expanding Montana de Luz’s available clean water
storage, reducing the quantity of water that must be shipped to the orphanage during power
outages, and helping Montana de Luz to become more self-sufficient. Initially, the team
planned to supply Montana de Luz with a generator. However, the team’s original research
revealed that the proper generator would cost about $3,500 (portable, from TEMCo). After a
discussion with Franklin Electric, the pump manufacturer, the team was made aware of the 20
kW kick-start to the pump, increasing the needed power output of the generator. TEMCo
offered a stationary generator rated with this high level of power, but the solution would cost
about $20,000. A variable drive frequency controller could be used to decrease this kick-start
power (making a lower power generator possible to use), but it is also a pricey solution, costing
about $600. This high cost caused the team to abandon this path to focus on a new solution of
increasing the water storage capacity at the orphanage. Maximizing Montana de Luz’s water
storage would also reduce the need for clean water to be brought to the orphanage during a
power outage, thus reducing Montana de Luz’s water costs and assisting Montana de Luz in
becoming more self-sufficient.
However, after assessing the feasibility of transporting a water tank from the city to the
orphanage and then up onto the current tank support structure, the team (in conjunction with
discussions involving MdL staff and course professors) decided that the hardships brought on
by this solution would outweigh its benefits. Once Saul visited Tegucigalpa to see such a water
tank, he found the size and weight of the tank to be much larger than originally expected. Due
to the size of the water tank, a semi-truck would most likely be needed to transport the tank to
MdL. Then, a crane would be the best option for lifting the 900 pound tank onto the platform.
Finally, the platform would most likely need to be reinforced since the nearly 13,000 pounds of
a full 1,500 gallon tank may not be supported by the current platform.
Also, after further investigation, the team discovered that a water supply truck was only
needed two or three times throughout the period of MdL’s existence. In the last calendar year,
MdL has never had to have water brought to the orphanage by truck. Initially, the team was led
to believe that MdL had to ship in water several times a year, especially during extended power
outages. Since the number of shipments was much lower than the initial assumption, and given
the high cost of a new storage tank, this solution is not economically feasible.
The team also considered completing a comprehensive assessment of a generator to power the
lift pump during power outages with the goal of the assessment being used to obtain funds for
a generator by a rotary club. However, the use of a generator was not deemed beneficial at this
time due to the lack of need for additional water when the electricity is not working.
BIODIGESTER
The main objective for this project is to get the biodigester currently at Montana de Luz in a
functioning state. This includes pumping out the present contents of the biodigester and
initializing the biodigester with manure. Once the manure is added into the biodigester the
main chamber will be able to restart the anaerobic digestion process.
A secondary objective for this project is to present the operational parameters for the
biodigester explicitly and in easy-to-use terms. This includes replacing the posters the team
made last year, which have faded with the sunlight, with new posters that are clearer and
placed in more appropriate locations.
TILAPIA POND
One main objective for this project is to repair the cracks in one section of the tilapia pond so
that the entire pond is functional. By the time the team departs Honduras, all three sections of
the tilapia pond will be operational and ready for Montana de Luz to stock with tilapia.
Another main objective of this project is to create a sustainable rotational schedule that
Montana de Luz can follow to maximize their annual yield of tilapia. This will be achieved based
on the knowledge of the tilapia’s life cycle and capacities of the current pond.
A secondary objective will be to evaluate the use of the current pump that was provided to
Montana de Luz last year. Currently, the pump is being used in the middle section of the pond
with the availability to be split into multiple sections. This objective will be evaluated and
assessed in country based on Montana de Luz’s current experience with the pump.
COST ANALYSIS
GENERATOR/STORAGE CAPACITY INCREASE
Increasing the storage capacity of Montana de Luz’s water supply would require purchasing a
5,000 gallon tank that would cost approximately $5,000 (price obtained from Saul on his visit to
Tegucigalpa). The team would also need to purchase PVC piping and sealing material, and incur
costs associated with transporting the tank from Tegucigalpa to the orphanage and renting a
crane to raise the tank from the ground to its support structure. A water truck costs
approximately 2,000 lempira, which is around $100. The trucks carry approximately 2,700
gallons of water, and this water lasts approximately two days during a power outage. Given
that MdL has only relied upon water from water trucks two to three times since it has been
opened, and that the water trucks cost 1/50 of the face-value of the water tank (excluding the
transportation costs associated with installing the tank), increasing the storage capacity in this
manner at MdL is economically inefficient.
BIODIGESTER
The manure obtained to initialize the biodigester was free since part of the team travelled to a
local farm and shoveled the manure themselves. However, the team had to pay two local men
$150 to clean out the biodigester; this was an unexpected cost since the solids pump was the
original method of removal. Furthermore, the piping was found to have excessive amounts of
leaks and needed to be replaced, costing the team around $50. A breakdown of the piping
materials can be found in the Bill of Materials in the Appendices.
The main instructional cost was for the instructional posters placed by the biodigester and in
the kitchens for the staff’s reference. The pricing for the cardstock, markers, frames, and other
materials can be found in the appendices with the bill of materials.
Keeping the biodigester running incurs no additional cost to the orphanage. It uses MdL’s food
waste to produce gas, and so only maintenance of adding food daily will be required.
As calculated in the Biogas Production Analysis in the Appendices, the biodigester has the
capacity to save Montana de Luz one third of its current cost of propane. Currently, MdL
spends approximately $100 per month on propane, so their savings could be as much as $33
per month or $396 per year once the biodigester is fully functioning.
TILAPIA POND
The only cost associated with the tilapia pond is the cost of cement to patch the cracks. The
cement was $25. However, this cost is easily justified by the stable protein source the tilapia
pond provides for the children’s diets. Montana de Luz was able to harvest roughly 300 fish
from one section of the pond in the past year. Given that each tilapia weighs approximately one
pound, Montana de Luz harvested 300 pounds of tilapia in one harvesting “season.” Also, an
objective of this project is to increase the yield yearly. Currently, it is known that the middle
pond has the ability to successfully hold 300 tilapia. The larger section of the pond is able to
hold either the same amount without aeration or 500 tilapia if the pond is aerated. The smaller
section of the pond is capable of holding 50 tilapia.l This information was found in the 2011
Tilapia Pond Team’s report. A professor at the University of Zamorano visited Montana de Luz
the previous year to assess the pond in order to provide these estimates. Each section of the
pond could be harvested every 6 months, or twice a year due to the tilapia’s life cycle.
Therefore, Montana de Luz could harvest approximately 1,700 tilapia a year, or 1,700 pounds of
tilapia a year. By harvesting more tilapia, Montana de Luz could potentially sell extra tilapia not
used to feed the children to nearby villages. The exact cost for which Montana de Luz could sell
each piece of tilapia is unknown and will have to be decided by the staff and directors at
Montana de Luz. However, Zamorano provided an estimate in previous years suggesting that
each pound of tilapia could be sold for 27 Lempira. Given the potential for an annual yield of
1,700 pounds of tilapia, Montana de Luz could generate approximately 45,900 Lempira in one
year from harvesting tilapia.
DETAILED PLAN OF ACTION
SATURDAY, MARCH 17 TH
Morning:

Travel to Honduras
Afternoon:

Arrive at Montana de Luz

Assess current state of the biodigester (if time allows)

Assess current state of tilapia pond (if time allows)
SUNDAY, MARCH 18 TH
Morning:

Excursion Day

Begin to pump out biodigester (if time allows)
MONDAY, MARCH 19 TH
Morning:

Meeting with Montana de Luz staff

Pump out biodigester (see Part 2 of manual in Appendix D)
o Stir contents of biodigester with large stick or pole
o Connect discharge hose to the pump
o Lower pump into the chamber of the biodigester through open cap, given that
the seal and cap are removed by Saul upon arrival
o Place discharge hose at a safe location where the biodigester’s contents will be
emptied (ask Montana de Luz staff for appropriate location)
o Turn pump on

Clean empty section of the tilapia pond

Begin patching cracks in tilapia pond
Afternoon:

Clean biodigester

Fill halfway with water

Pump out contents of biodigester following procedure above

Test pH of water being removed (should be below 8.0)

Assess patching in cracks and make changes if necessary

Assess current tilapia pond pump usage

Test pH in tilapia pond water
TUESDAY, MARCH 20 TH
Morning:

Assess patching in cracks. Fill section with water and mark water level

Begin instructional posters for biodigester

Begin developing rotational schedule for tilapia pond
Afternoon:

Discuss with Montana de Luz staff on where to obtain manure

Make visit to location if necessary (manure needed Wednesday)

Assess biodigester

Assess water level of tilapia pond. Water level should drop slightly due to saturation of
the concrete and soil. If water level drops too significantly, cracks may need to be
repaired.
WEDNESDAY, MARCH 21 ST
Morning:

Obtain manure, at least 150 kg

Fill biodigester with water until water level reaches effluent pipe

Initialize biodigester with manure
o If manure is dry, moisten it with water
o Break manure into pebble-sized pieces
o Place manure in biodigester through the top hole
o Stir contents of the biodigester with large stick
o Replace cap of biodigester and reseal cap with cement
Afternoon:

Complete instructional poster for biodigester

Complete rotational schedule for tilapia pond
THURSDAY, MARCH 22 ND
Morning:

Check status of biodigester

Observe inflow and outflow areas

Look to see if any effluent is coming out of the pipes

Assess water level of tilapia pond for leaks
Afternoon:

Extra time to complete instructional posters for biodigester and rotational schedule and
instructions for tilapia pond
FRIDAY, MARCH 23 RD
Morning:

Check status of biodigester

Check for gas coming out of gas pipe

Install instructional posters near biodigester
Afternoon:

Debrief with Montana de Luz staff

Train staff on correct use of biodigester

Train staff on rotational schedule of tilapia pond
SATURDAY, MARCH 24 TH

Say goodbye to the kids

Travel back to Columbus
Special Note: The earlier the biodigester is initialized, the better. If time allows before Monday
to pump out the biodigester, the team will do so. If the biodigester is pumped out sooner, the
manure will hopefully be purchased sooner to initialize the biodigester as early as possible.
IMPLEMENTATION
Note
For specific details on results and discussion of the results, please refer to the Results and
Objectives Achieved section of the report.
Monday
The team began working on their projects on Monday, March 14th. Their work began with a
meeting with Montana de Luz staff on Monday morning. The team informed the staff of their
plan to empty the biodigester and the two unused sections of the tilapia pond, repair the cracks
in the tilapia pond with hydraulic cement, and to prime the biodigester. Inquiries were made
about how to obtain manure to use in initiating the biodigester.
The remainder of the morning was spent pumping out the two unused sections of the tilapia
pond and assessing what the best way to empty the biodigester would be. Hiring men from
Nueva Esparanza (a neighboring town) to remove the solids in the biodigester was determined
to be the best option. To ensure that hiring the men would be economical and that MdL would
still save money by using the biodigester rather than propane, the team spent the afternoon
researching and calculating how much energy could be harnessed from the biogas versus the
propane.
Tuesday
On Tuesday, March 15th, the team began the day by checking their calculations. It was
determined that paying men to empty the biodigester would still result in net savings for MdL
over the next few years. Therefore, the team requested Saul to find men to do the labor. The
afternoon was spent cleaning out debris in the empty portions of the tilapia pond, using chalk
to mark where the cracks in the pond that needed to be filled were, and designing posters
about what foods are acceptable compost materials for biodigester influent.
Wednesday
Wednesday the hired men began emptying the biodigester. While the men worked on the
biodigester, the team repaired the tilapia pond. First, a member of the team would expand a
crack with a chisel so that the hydraulic cement would more easily fill the fissure. Then, another
team member filled the fissure with cement. One more team member followed and applied
pressure to the wet cement to ensure that a strong seal was formed. The team was able to
complete repairing the pond by lunch.
The afternoon was spent creating composting posters and testing the biodigester’s gas lines for
leaks. To test for leaks, the gas lines were cut and then attached to an air compressor. The PVC
gas lines were then coated with water and dish soap. The lines were pressurized and the team
watched for the soap bubbles that would indicate a leak to develop on the PVC. Several leaks
were found and it was determined that it would be more sustainable to replace the PVC than
repair all of the leaks. The remainder of the afternoon was spent making a list of all of the
supplies needed for reconstructing the gas lines.
Thursday
The team decided to divide and concur the day’s tasks. Two team members spent the morning
shoveling and organizing old compost that was being stored to feed to the biodigester.
Meanwhile, the other team members went with Saul to obtain manure with which to prime the
biodigester. By the end of the morning, the compost was sorted, the hired men had completed
emptying the biodigester, and the team had acquired a truck full of manure. Most of the
afternoon was spent finishing biodigester signs and purchasing the pipes and fittings needed for
a new gas line.
Friday
The morning of the final work day of the trip was spent tearing down and replacing old gas
lines. The new lines were made the same size as the old ones. Wire and zip-ties were utilized to
help support the structure.
During the afternoon, the team passed off their work to MdL staff. The team explained to the
tias what was and was not allowed to be composted. The team also explained that one bucket
of compost should be added for every two buckets of water. After the meeting, the team took
measurements of the inside of the biodigester and completed taking pictorial documentation of
the projects. Additionally, the team hung signs as to appropriate composting materials in the
kitchen, by the trash cans where the children clean-up, and in the service team kitchen.
RESULTS AND OBJECTIVES ACHIEVED
GENERATOR/STORAGE CAPACITY INCREASE
Unfortunately, the water supply project of increasing the orphanage’s storage capacity during a
power outage was not implemented. Upon further investigation, the supply tanks were found
to be not only too bulky and costly to purchase and install, but MdL was found to have no need
of expanding their water supply system.
Within the last few weeks of the quarter, the team decided to follow Saul’s recommendation to
purchase a 5,000 gallon tank rather than a 1,500 gallon tank for which the team had obtained a
price quote. Since this purchase would be in-country, the team requested that Saul find out the
size and cost of the 5,000 gallon tank. Although Saul originally estimated the cost at $1,300,
thought the orphanage had a truck large enough to transport it from Tegucigalpa, assumed it
would be small enough to lift from the ground to the support structure, and believed the
support structure would hold the new tank when full of water, his trip to Tegucigalpa proved
these thoughts to be false. The actual price of the tank was approximately $5,000 and the
diameter of the tank was too large to fit on the current platform.
Furthermore, after checking their records over the past years, MdL staff contacted the team in
regards to the number of water trunks brought to the orphanage: only two or three had been
used since MdL came into existence, with neither of those being in the past year. With this
information, the team concluded that increasing the storage capacity of the orphanage would
be unnecessary since the orphanage’s current water supply has historically supported them,
even during a power outage.
BIODIGESTER
The main objective of the biodigester project was to leave it in a fully-functioning, fullyoperating state. Although the biodigester was not left in operation, it was left in a state ready
to be initilized. Upon arrival and after looking into the biodigester with the lid removed, the
contents of the biodigester were determined to contain too many solids to remove with the
pump purchased after last year’s team returned from its trip. The contents clogging the
biodigester resembled wet mulch, and the issue then became how to remove the solids. Saul
suggestion hiring two men from the local village to clean the biodigester since they could
complete the task faster than the team; additionally, the task of cleaning the biodigester was
deemed unsafe for the team to do themselves.
Before a final decision on paying men to clean the biodigester was made, the team evaluated
the cost MdL would save when biogas could be used to power the chicken processing stoves as
opposed to the current use of purchased propane gas. A volume of biogas produced over the
course of 15 days was approximated and compared to the volume of propane used by the
orphanage for this use in a month. These gas volumes were then converted to energy and
compared. These calculations and assumptions are shown in the Appendices proved that the
biodigester could replace about 1/3 of the orphanages propane use over the course of 15 days.
Once this information was shared with Saul, he decided it was sufficient ground to continue
with the biodigester project because he had only planned to use the gas for the stoves in the
chicken coop and to power lanterns above the pig pens (to be installed later).
Once the men were hired, the team used that time to procure manure from a local cow farm.
They retrieved a truck bed full of manure, which was about 560 kg, and filled three 55 gallon
barrels with this manure for future use. Calculations for these amounts can be found in the
Appendices. Once the biodigester was completely emptied and its size was observed, this
amount of manure was determined to not be large enough. The team debated returning to the
farm to procure more manure but decided against this due to another team’s work on the lift
pump: the pressurizing pump was not functioning at the time so water would not be available
from the agriculture tanks to flush out the biodigester then mix with the manure in order to
initialize it.
Nevertheless, the team took advantage of the biodigester, empty with its cap removed, and
took measurements to estimate its size. Using a laser measuring device, the team dimensioned
the main chamber of the biodigester. The results can be seen in Figure 2.
Figure 2: Dimensioned Sketch of the Biodigester’s Main Chamber
Additionally, the team decided to focus on the pipeline for the biodgas. The pipeline was coated
with soapy water and using an air compressor, air was pushed through the PVC. Where bubbles
were formed, leaks were assumed to exist. Due to significant amount of leaks in the piping itself
along with around a valve, the team decided to redo the entire pipeline. The team purchased
new PVC, valves, and couplings from the local ferretería (hardware store). Before making the
trip to the store, the team measured the approximate lengths of piping necessary. A
dimensioned sketch of the piping system can be seen as a top view in Figure 3.
Figure 3: Dimensioned Top View Sketch of the Biogas Pipeline
The team made a new piping system modeled from the old one. The new piping can be seen in
Figure 4 and 5.
Figure 4: New PVC Pipeline for Biogas
Figure 5: New Gas Gauge on Piping
After the pipeline was completed, progress on the biodigester was halted. The team informed
Saul to obtain enough manure to fill the biodigester with a two parts water to one part manure
ratio until the mixture covered the two inlet/outlet pipes in the main chamber, thus assuring it
would be airtight. A new pressure gauge was also installed so that Saul could monitor the gas
pressure inside the main chamber.
Furthermore, new posters were made that explained what could and could not go in the
biodigester. Each poster contained the following information:

Good (Bueno)
o Beans (frijoles)
o plantains/bananas (platano)
o watermelon (sandia)
o tortilla (tortilla)
o lettuce (lechuga)
o tomato (tomate)
o pineapple (pina)
o rice (arroz)

Bad (Mal)
o Eggs (huevos)
o
bones (huesos)
o meat (carne)
o egg shells (cascarde de huevo)
o paper (papel)
o milk (leche)
o cardboard (carton)
o plastic (plastico)
These signs were placed in plastic frames, sealed with silicon caulk, and placed near the
children’s composting bin, the kitchen’s composting bin, and in the kitchen for service teams.
Saul, the cook, and one of the tias were trained on appropriate materials for the biodigester.
Figure 6 shows a pictures of these posters.
Figure 6: Composting Posters Placed at MdL
The composting method inside one of the pig pens was abandoned since egg shells were placed
inside of it along with other food scraps. Although the team did clean the composting area, too
many egg shell pieces were present for them to be removed. Saul was instructed to use the
current compost for the gardens and to start again with compost for the biodigester, putting
only fruit, vegetable, and grain remains in it with no meat, bones, or egg shells.
TILAPIA POND
The tilapia pond was evaluated and pumped out on the morning of Monday, March 19th. The
smallest portion of the pond was found to be in use, containing about 40 red tilapia. The team
tested the aeration pump and found that it was still in exceptional condition. The team also
learned the materials needed to splice the pump so it could supply water to more than one
section of the pond had been obtained. The medium sized middle section and the large section
of the pond were not in use.
The team’s first task was to remove the small pools of stagnant water in the two unused
sections of the pond. This would let the team go into the pond to effectively work on examining
it more closely and work on repairing the cracks. The majority of the water was removed with a
pump that had been sent to MdL by the previous year’s biodigester team. The final pools of
inch-deep water were too shallow for the pump to effectively remove. Instead, the team
scooped the muck into buckets and manually lifted it out of the pond.
The team waited until Tuesday, March 20th to complete their work so that the pond would be
completely dried out by the sun. The assessment of the pond revealed multiple long, thin cracks
in the side walls as well as bottoms of both of the empty sections of the pond. Due to the
number of cracks found, the team decided it was necessary to focus on the fractures that would
affect the quality of the pond the most so that enough cement could be saved to seal the
biodigester after it has been primed. The minor cracks in the walls connecting the ponds were
deemed unnecessary to repair because any water going through the cracks would simply move
to another section of the pond rather than seep into the ground. Instead, the team focused
their attention to the cracks on the outer sides and the bottom of the pond. The team worked
with Saul to identify all of the fractures that may be causing leakage and marked them with
chalk.
Once all of the damage-causing cracks were located and marked, the team concentrated on
repairing the cracks. One team member worked with a chisel to open the surface of the
fractures so that the cement could be more easily forced into them. The other team members
followed with the wet hydraulic cement. They cleaned the cracks of dust then subjected
pressure on the cement to force it into the cracks and to help it set.
The repairs were completed on Wednesday, March 21st. Due to pump problems associated
with another team’s work, the water distribution system was not operational. Therefore, the
team was unable fill the pond with water for testing.
Education on the rotational schedule that had been planned in the pre-trip work was not
implemented. Before arriving at the orphanage, the team had been concerned that the
orphanage may not be utilizing the rotational schedule left by the previous team due to lack of
training. However, upon speaking with the staff, it was found that the schedule was not being
used only because of the cracks in the pond. The staff was aware of how to execute a rotational
schedule and planned on implementing one after the pond had been repaired.
FUTURE RECOMMENDATIONS
GENERATOR/STORAGE CAPACITY INCREASE
As demonstrated through investigation of this issue, having water during power outages is not
as big of a problem as initially expected. Nevertheless, this could be due to the orphanage
actively attempting to conserve water in a power outage combined with a lack of water
pressurization from the distribution pump. If the latter is the case, providing alternative
sources of power to the water supply pump and also the distribution pump together could
prove to be a large improvement in the well-being of the orphanage. Obviously, these power
sources could not be electrical, and as demonstrated in this report, generators are not the most
economical of options so new options would need to be pursued.
Furthermore, electricity proves itself to be a consistently large expense for Montana de Luz. If
an affordable, grid-free energy source could be implemented for the water system, the
orphanage would not only save money on the cost of electricity, but also have power for both
of its pumps during a power outage.
BIODIGESTER
Currently, the biodigester is emptied with new gas lines in place for future usage. Before
initiating the biodigester, it will need to be flushed with water to ensure that all particles that
could potentially clog it are removed. Once flushed with water, the biodigester will need to be
given an initial charge of cow manure -- approximately 12 barrels (660 gallons) mixed with 24
barrels (1320 gallons) of water. The calculations used to obtain these values can be found in
the Appendices. Once this combination is added to the main chamber and stirred, the
biodigester will need to be sealed by putting the lid back on top and thoroughly cementing it
shut, ensuring that the seal is airtight. The initiation process does not give immediate results,
although some amount of pressure from the biogas should be able to be seen within a week
(the pressure will be around 10 psi, if not smaller).
Once the biodigester is operational, scraps from the kitchen can be added to it when mixed
with water. No egg shells, meat, or animal bones can be put into the biodigester. For every
bucket of compost added to the biodigester, two buckets of water will need to be added.
Since there are strict rules about what can and cannot be added to the biodigester, and since
the children are not accustomed to separating their meat from their plant-based food scraps,
the orphanage may consider only taking scraps from the kitchen as influent for the biodigester
and using scraps from the children's meals for simple composting.
Since the gas stoves for chicken preparation are not used on a daily basis, pressure will need to
be relieved from the gas lines if it reaches a high level (above about 10 psi). It can be relieved
by burning it off on the stop or opening the left valve, which currently goes to a gas line
unattached to anything. Furthermore, since the biodigester may produce gas at a rate larger
than what they use for the chickens, the orphanage may wish to consider adding another gas
line from the biodigester. Saul currently has a gas line traveling to a spot for potential gaslights
above the pig pens, and the biogas could be used for this purpose if lights are added. If the
orphanage's food scrap amount ever greatly increases, Montana de Luz could consider adding a
gas line to the main kitchen since the gas output would be larger with a larger amount of
influent.
TILAPIA POND
Evident from the large amount of cracks the team filled while on-site, the tilapia pond is in dire
need of a permanent solution to the cracking problem so that the pond does not need to be
periodically drained and patched. Although potentially expensive, lining the tilapia pond with a
waterproof liner much like that used in pools would be highly beneficial to MdL and would
reduce the amount of maintenance the tilapia pond requires. Saul mentioned lining the pond
or re-cementing the pond once the current fish in the pond are harvested.
Aside from solving the problem of the pond cracking, no extensive work should be necessary on
the tilapia pond during future trips. However, it is recommended that future teams check with
MdL before the trip to see if any maintenance is needed. Maintenance that may be needed
within the next couple years includes assessing the condition of the aeration pump and the
water quality for the fish.
Testing the pond’s water quality for an assessment of the tilapia’s living conditions may be
beneficial if the orphanage begins obtaining less than ideal yields. In this scenario, prior
research on the ideal chemical conditions of tilapia’s living conditions and how to fix any
problems that may be found would be necessary before the trip.
APPENDICES
A. REFERNCES
B. TEAM AGREEMENT
C. PUMP INFORMATION
D. E-MAIL CORRESPONDENCE WITH STAFF
E. BIODIGESTER AND COMPOST INSTRUCTION MANUAL, ENGLISH VERSION (CREATED
FROM 2011 BIODIGESTER TEAM)
F. QUESTIONS AND ANSWERS FROM MDL STAFF (“PARKING LOT”)
G. BILL OF MATERIALS
H. BIOGAS PRODUCTION ANALYSIS
I.
MANURE PROCURED ANALYSIS
J.
INITIALIZATION VOLUMES ANALYSIS
K. HELPFUL SPANISH WORDS AND PHRASES
APPENDIX A: REFERENCES
References

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


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




Dr. John Merrill: Lead and organized the Engineering 692 class, supported and advised
the team when necessary
Dr. Howard Greene: Resident advisor for the Montana de Luz trip, served as a technical
resource for all projects, answered questions and advised the team
Carlos Montoya: Helped with any Spanish needs and pricing for in-country items
Dr. Roger Dzywonczyk: Presented to the class on appropriate documentation styles and
provided the breakdown of documentation used in this report
Brad Doudican: Resident advisor for the Montana de Luz trip last year, including the
previous biodigester team; always a willing resource for information, opinions, and
pictures from years past
Montana de Luz Staff In Honduras: Quickly answered all questions to the best of their
knowledge, sent pictures of pumps and other systems
Montana de Luz Staff In Columbus: Showed genuine support for our projects from the
beginning until the end, came into class when needed to approve or questions projects
Rachel Childers: Spoke with the group on initializing a biodigester and what to expect
when this is done, gave the group research information of water to substrate ratios for
influent materials, gave the group a chart (in Biogas Production Analysis Appendix)
relating volume of biogas per ton of substrate)
Betty Lise Anderson: Helped the team obtain a large-scale ammeter
Jim Moncrief: Provided the team with a large-scale ammeter
Biodigester Team from 2011: Laid the groundwork for this project, provided vital
documentation, wrote manuals for biodigester operation
Tilapia Pond Team from 2011: Laid groundwork for this project, provided vital
documentation used as background research in this report
Lewis Contractor Sales Website: Offered details of the BJM solids-handling pump
Northern Tool + Equipment Website: Offered details of the Apache discharge hose
Franklin Electric: manufacturer for water supply pump, answered questions regarding
power needed to start the pump which lead abandoning the generator solution
TEMCo Industrial Power: offers information on many different types of generators, used
this company to price both size generators considered along with a variable frequency
drive control
o http://www.temcoindustrialpower.com/products/Portable_Generators/GG0106
.html
o http://www.electricpowergenerator.com/industrialtowablestandby.html

o http://www.temcoindustrialpower.com/products/Variable_Frequency_Drives/C
80008.html
Sources for Biogas Production Analysis
o Energy density of natural gas vs. propane:
http://www.buzzle.com/articles/propane-vs-natural-gas-comparison.html
o Density of methane and conversion from lbf to lbm: Engineering Toolbox
(website)
APPENDIX B: TEAM AGREEMENT
APPENDIX C: PUMP INFORMATION
BJM Solids-Handling Pump (for Removing Solids from Biodigester)









Electric, submersible, solids-handling pump, portable pump
0.5 HP
115 volts
40 lbs
8.50 inches wide, 15.80 inches tall
Requires hose (see below)
Has an electric cord to power the pump
Distributor’s website:
http://www.lewiscontractorsales.com/Merchant2/merchant.mvc?Screen=PROD&Produ
ct_Code=11401&Category_Code=
Apache discharge hose
 2 inch diameter
 PVC
 50 feet long
 65 PSI = max pressure
 14.0 pounds
 Distributor’s website:
http://www.northerntool.com/shop/tools/product_10212_10212?cm_ite=50621&c
m_pla=Water%20Pumps%3EWater%20Pump%20Accessories&cm_cat=Google&cm_
ven=Aggregates
Water Supply Pump








60 Hz
7.5 hp
230 V
21.8 A
3450 RPM
3-phase
Will most likely need a variable frequency drive controller
Figure C1 shows the information plate from the pump
Figure C1: Information Plate from Water Supply Pump
APPENDIX D: E-MAIL CORRESPONDENCE WITH STAFF
Howard,
Your welcome!
Saúl went to Tegucigalpa yesterday to get an estimate for a rotoplas tank (22000 liters,
approx. 5,800 gallons). Unfortunately, Saúl's initial estimate was way off. The actual price of a
tank of this size is nearly quadruple what he anticipated, coming in at 94,000 lempira (nearly
$5000). The dimensions of the tank are: 3.4m (height) and 3m (diameter). Saúl has the phone
number of the person who attended to him, so if any further questions/estimates are needed, it
will be much easier and faster.
I also confirmed with Saúl that the PVC inner diameter is in fact 1/2".
In the last calendar year, we didn't have any truckloads of potable water delivered to MdL.
During the entire time that Saúl has been working at MdL, water has only ever been delivered 2
or 3 times.
Amanda
After the email, the water supply project became obsolete. Instead, the team will be
concentrating on working on the biodigester and the tilapia pond.
Below are some of the emails and answers to questions that the team had utilized in their work
for their work on this towards improving the supply system. Some of the questions include:
requests for dimensions of the platform, requests for materials of the platform, confirmations
that Saul knew the price and size and how to move a ~5000 gallon tank, requests for
dimensions of the proposed larger tank as well as requests for general information about the
system.
EMAILS RECEIVED
From: Amanda Hall [mailto:a.hall126@gmail.com]
Sent: Tuesday, March 06, 2012 12:30 PM
To: Howard Greene
Subject: Re: More Questions for Saul
Howard,
Your welcome!
Saúl went to Tegucigalpa yesterday to get an estimate for a rotoplas tank (22000 liters,
approx. 5,800 gallons). Unfortunately, Saúl's initial estimate was way off. The actual price of a
tank of this size is nearly quadruple what he anticipated, coming in at 94,000 lempira (nearly
$5000). The dimensions of the tank are: 3.4m (height) and 3m (diameter). Saúl has the phone
number of the person who attended to him, so if any further questions/estimates are needed, it
will be much easier and faster.
I also confirmed with Saúl that the PVC inner diameter is in fact 1/2".
In the last calendar year, we didn't have any truckloads of potable water delivered to MdL.
During the entire time that Saúl has been working at MdL, water has only ever been delivered 2
or 3 times.
Amanda
On Mon, Mar 5, 2012 at 4:13 PM, Howard Greene <Howard_Greene@engadmin.ohiostate.edu> wrote:
Hi Amanda,
One question (probably for Karen, not Saul): During the last calendar year, how many
truckloads of potable water (at ~$100 per truckload as we learned from Saul) was it necessary
to have delivered to MdL due to power outages? If you don’t know exactly, could you estimate
it?
This answer will be very helpful as we further propose solutions.
Thanks,
Howard
__________________________________________________
From: Amanda Hall [mailto:a.hall126@gmail.com]
Sent: Monday, March 05, 2012 9:25 AM
To: Howard Greene
Cc: Carlos Montoya (montoya-rodriguez.1@buckeyemail.osu.edu); John A. Merrill Ph. D.
(merrill.25@osu.edu); Dzwonczyk, Roger (Roger.Dzwonczyk@osumc.edu); Ruth DeYoe
(ruthdeyoe@gmail.com)
Subject: Re: More Questions for Saul
Howard,
Sorry for the delay! Here are the additional pictures of the water filtration system. Saúl is in
Tegucigalpa getting an estimate on the water tank. I will send you that information as well as a
confirmation on the PVC as soon as I can. Thanks for your patience.
Amanda
On Fri, Mar 2, 2012 at 9:25 AM, Howard Greene <Howard_Greene@engadmin.ohio-state.edu>
wrote:
Hi Amanda,
Thanks for the responses. We look forward to getting Saul’s cost estimate and dimensions for
the tank and the pictures when you have your Internet restored. (As far as the funds for this
purchase – these will have to be approved, of course, by Erika/Ruth. I actually meet with them
in about an hour to discuss all of the purchases and how they will be arranged. (If Saul is to buy
or pay for anything, approval and funds will come through his usual channels at MdL, not
us. We do not have the authority to have Saul do anything without prior approval from MdL).
Yes. Sorry about #2 below. We already had length and width. We just needed the
thickness. You have answered the questions just fine. Thanks!
#4 This is interesting and I will make sure we discuss it today with Ruth/Erika.
#5 Usually PCV plumbing is specified by its inner diameter, so if you measured the outer
diameter as close to 1”, then it is probably ½” stock PVC. Saul would know if it is ½ “ stock
(inner diameter). Might you ask him? Thanks!!
Howard
__________________________________________________________
From: Amanda Hall [mailto:a.hall126@gmail.com]
Sent: Thursday, March 01, 2012 5:02 PM
To: Howard Greene
Cc: Carlos Montoya (montoya-rodriguez.1@buckeyemail.osu.edu); John A. Merrill Ph.
D. (merrill.25@osu.edu); Dzwonczyk, Roger (Roger.Dzwonczyk@osumc.edu); Ruth
DeYoe (ruthdeyoe@gmail.com)
Subject: Re: More Questions for Saul
Hey Howard,
Sorry for the delay on these answers/photos. Our internet connection has been a little slow here
these past few days.
1. What are the specifications on the new poly water tank that he is planning on buying in
Teguc?

Gallon capacity -

Dimensions (diameter, height)

Lead time

Price confirmation
I will have more detailed information regarding this question tomorrow after getting an
estimate in Tegucigalpa. Since Saúl isn't aware of exactly what your plans are (he's just
been answering questions and making suggestions), he never actually made concrete plans
to purchase a new poly water tank. We still have time though, as he said it shouldn't take
more than a couple days to acquire (if it is not in stock). As soon as we get a confirmation
from you, the tank can be purchased. Just to confirm - this is a cost that will be covered by
your team, correct?
2. What are the dimensions of the existing concrete platform (length, width, thickness)?
5.3m x 2.9m (length and width). Thickness is between 6 and 8 inches. (I believe I already
provided the length and width in a set of questions a week ago? If not, I must have
answered a previous question wrong. Please check this? I would have to have previously
given you the wrong set of dimensions.)
3. Does Saúl have a method to get the new, larger tank on the existing platform?
Yes.
4. Does MdL have plans for what they would like to do with the old (3) tanks?
Tentatively, the two larger tanks (800gallons) could replace the water tanks at the two staff
houses in Nueva Esperanza. The current tanks down below are significantly smaller and
we consistently run out of water each week. Saúl said there aren't any specific plans for the
other, smaller tank. It could either be utilized elsewhere at MdL or sold.
5. What is the material and size of the plumbing underneath the faucet that has the drinking water
filter? Is it 1/2" PVC? Could we get a picture or two of this plumbing under the cabinet?
PVC, approx. 1". I took the pictures already, but I am unable to attach them right now due
to a slow Internet connection.
As always, I hope these answers are helpful. I will update you with the information about the
new poly tank as soon as I get the estimate and specs. I will also attempt to attach the plumbing
photos tomorrow as well.
Amanda
On Thu, Mar 1, 2012 at 10:40 AM, Howard Greene <Howard_Greene@engadmin.ohiostate.edu> wrote:
Hello Amanda!
Here are the latest translated questions. Thanks again, in advance, for your help in getting
these answered by Saul - we are entering the “home stretch! I look forward to meeting you
and working together at MdL!
1. What are the specification on the new poly water tank that he is planning on
buying in Teguc?

Gallon capacity

Dimensions (diameter, height)

Lead time (Is it in stock in Teguc or does it take some time to order it?)

Confirm the price (25000 Lempiras?)
1. Cuáles son las especificaciones del nuevo tanque de rotoplas que él está planificando
comprar en Tegus?

Capacidad en galones

Dimensiones (diámetro, altura)

Tiempo de adquisición (esta el tanque en inventario en Tegus o toma tiempo
ordenarlo?)

Confirmar precio (25,000 lempiras?)
2. What are the dimensions of the existing concrete platform (length, width, thickness)?
2. Cuáles son las dimensiones de la plataforma de concreto existente (largo, ancho,
grosor)?
3. Does Saul have a method to get the new, larger tank on the existing platform?
3. Tiene Saúl un método para montar el tanque nuevo en la plataforma existente?
4. Does MdL have plans for what they would like to do with the old (3) tanks?
4. Tiene planes MdL para los tres tanques viejos que quedarían sin uso?
5. (Water Filter Question) What is the material and size of the plumbing underneath the
faucet that has the drinking water filter? Is it ½” PVC? Could we get a picture or two of this
plumbing under the cabinet?
5. (Pregunta del filtro de agua) Cual es el material y tamaño de la tubería debajo del
grifo que tiene el filtro para tomar agua? Es de 1/2'' PVC? Podríamos obtener una foto o
dos de la tubería debajo del gabinete?
Gracias!
APPENDIX E: BIODIGESTER AND COMPOST INSTRUCTION MANUAL, ENGLISH VERSION
(CREATED FROM 2011 BIODIGESTER TEAM)
Biodigester and Compost Instructional Manual
Provided for Montana de Luz
By
The Ohio State University 2011 Biodigester Team
Table of Contents

Part 1-Compost*

Part 2-Biodigester Start-Up

Part 3-Biodigester Operation*

Part 4-Biodigester Trouble Shooting
*posters pertaining to these instructions were posted in the compost area by the biodigester
team in March 2011
Part 1: Compost
A three stage compost pit has already been constructed in the unused animal pen closest to the
biodigester.
Stage 1 of the compost process has been designated for the pit closest to the biodigester. In
stage 1, place only organic scraps such as beans, grain products, fruits, and fruit peels. Under
no circumstances should any regular garbage, such as plastic, paper, metal, meat, or bones be
placed in the compost pit.
While at Montana de Luz, the biodigester team started the compost process by placing organic
waste in stage 1 and stage 2. All new organic material should be placed in stage 1. Every two
weeks, each stage should be turned to the next stage to allow proper mixing and aeration.
During the dry season, each stage should be moderately watered once a week to help the
compost process.
2011 Stage Turning Schedule
Wednesday March 23rd (Initial) Wednesday June 22nd
Wednesday September 14th
Wednesday April 6th
Wednesday July 6th
Wednesday September 28th
Wednesday April 20th
Wednesday July 20th
Wednesday October 12th
Wednesday May 11th
Wednesday August 3rd
Wednesday October 26th
Wednesday May 25th
Wednesday August 17th
Wednesday November 9th
Wednesday June 8th
Wednesday August 31st
Wednesday November 23rd
If stage three gets overfilled with partially composted material, it is ok to transfer excess
material from stage 3 back to stage 1 and/or stage 2 to allow more time for material to fully
compost.
Organic material in stage 3 should be ready to charge the biodigester or use as fertilizer in 6-8
weeks. When fully composted, the material should look mostly like dirt with few large pieces of
organic material.
To use the composted material as fertilizer, spread material in the garden and mix with the dirt.
Directions on how to use composted material to charge the biodigester is discussed in Part-3.
Part 2: Biodigester Start-Up
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Evacuate gas from biodigester by opening all valves, including the valve on the stove in
the chicken coup.
Break seal and remove cap over main chamber being careful not to cause sparks or
break the gas pipe leaving the biodigester.
Stir the contents of the biodigester with a large stick or pole.
Lower solids removal pump into the main chamber and following the instructions for
use included with the pump (NEVER ENTER THE CHAMBER). Preferably pump the
biodigester contents through the back fence and away from the area.
Fill the biodigester halfway with water and stir again. Test water pH level with chemical
test kit left by the biodigester or tilapia team. Instructions for use of chemical kits have
been provided with their package.
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If pH is above 8.0, clean out the biodigester and continue process until pH reads 8.0 or
below. If pH is below 8.0 continue to next step.
Fill the biodigester with water until it reaches the level of the top of the effluent pipe.
Charge with atleast 150 kg (approximately 0.3 cubic meters) of cow manure. Most cow
manure is best, if the manure is dry, pre-moisten by soaking or break up the manure
into pebble size pieces before adding to biodigester. Stir Contents of biodigester again.
Replace the cap over the main chamber with an air tight seal (with out an air tight seal,
the biodigester is useless) and close all valves on the gas pipes including the stove.
Allow to sit for 4 to 6 weeks before using gas. After 2 weeks, compost may start being
added according to the instructions in Part 3.
At this time, there should be no smoking or open flame around the biodigester.
Part 3: Biodigester Operations
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After adding initial charge of cow manure and allowing it to sit for 2 weeks, you should
start adding charges of compost at regular intervals into the influent pipe of the
biodigester.
When charging the biodigester ensure the removable pipe in the influent well is in place
with the taped end toward the top.
Obtain half a bucket of compost material from stage 3 of the compost pit and place in
the influent well (NOT IN THE INFLUENT PIPE)
Fill the influent well with water up to the tape line on the pipe and stir.
After Stirring, remove the pipe from the well and allow the water and compost to drain
down the pipe into the bio digester.
Repeat steps 3-5, one total charge should be 1 bucket of compost and 2 wells of water.
The biodigester should be charged 2-3 times per week. Charging every Monday,
Wednesday, and Friday is a suggested charging pattern. If a charge is missed, it can be
added the next day or skipped with no impact on operations.
The biodigester should be charged regularly even when not used often to ensure ratio
of contents and water level remain at suitable for proper use.
Remove the effluent from the effluent well and use as fertilizer for the garden. Water
should be visible in the pipe but water in the well should not be covering the pipe.
After 4 to 6 weeks, the chamber should be filled with gas and ready to use to light the
stove.
Before lighting the stove, open the stove valve and hold a feather or other easily pliable
object in front of the gas outlet. If the feather is blown away from the outlet, the stove
is ready for use. If the feather is sucked into the outlet, do not light, the flame will be

sucked into the chamber and could cause an explosion. If the feather does not move,
the biodigester is not producing gas and trouble shooting procedures should be
followed.
The biodigester should provide enough gas to provide use of the stove for atleast 4
hours at a time. After many uses over a period of time, you should be able to gauge the
length of usage accurately.
Part 4: Biodigester Troubleshooting
I. The following procedures should be followed when the biodigester has been found to not be
producing gas properly
1. Check to make sure the pH of the effluent is between 7.0 and 8.5
a. Stir the contents of the main chamber with the flexible medal rod found
near the biodigester.
b. Add one influent well full of water to the biodigester
c. Obtain a sample of effluent from the effluent well and test for pH.
If the pH is lower than 8.5, continue to Part 4 step 2. If pH is
higher than 8.5. Follow the instructions in for start up from Part 1, step 1.
2. Check to make sure the chamber is air tight.





Make sure water is visible in the effluent pipe.
Make sure all the valves including the valve at the stove are closed and that a gas pipe is
not ruptured.
Check to make sure the seal on the cap to the main chamber is air tight and not cracked
or broken.
If anything is found to compromise the air tight seal of the main chamber, follow the
instruction for start up from Part 1 step 8.
If the biodigester continues to not produce gas after executing trouble shooting step 2,
follow the instructions for start up from step 1.
References and additional information about biodigesters can be found at the
following websites
http://www.appropedia.org/Biodigester
http://www.fastonline.org/CD3WD_40/JF/432/24-572.pdf
APPENDIX F: QUESTIONS AND ANSWERS FROM MDL STAFF (“PARKING LOT”)
Date
Posed
Posed To:
Question
Date Answered
1/30/2012
Answer
It appears that the 2 nonchlorinated tanks (1000 gal
total) normally used for
agriculture purposes are
actually being used as backup
- the pressure and flow are
low and this lasts only about 1
day. The 2200 gallon supply in
the 3 primary storage tanks
may also be being used as a
backup supply (see Q. 13). A.
On an average day, the water
demand is 5000 gallons/day;
however, when power goes
out, the 2200 gallons in the
storage tanks is sufficient for
one day.
The plumbing at MdL is NOT
"off limits" to design changes;
however, any work or
maintenance that will be
necessary AFTER the
departure of the OSU
engineering team needs to be
carefully considered.
Yes; however, the current
system does not separate
grey water from black water.
A new system would need to
be created. Saul thinks its
feasible.
Confirm the storage capacity of the three
primary water tanks.
1/19/2012
800 + 800 + 600 = 2200 gal
Approximately how long does it take the
existing lift pump to fill the 3 storage
tanks when they are empty?
1/30/2012
2 hours
Yes. Saúl confirmed that a
functional biodigestor would
be very positive for MdL.
While he said that it requires
some initial maintenance
(that he has not been able to
carry out), additional
maintenance/upkeep is
minimal. One of the problems
is that there is a general lack
of knowledge about - or
understanding of - the
mechanics and use of
biodigestors at MdL.
What is the average water demand at
MdL in gallons/day? Similarly, when the
electricity goes off, how long (on
average) does it take to deplete the
volume of water in the storage tanks?
1/18/2012
Ruth De
Yoe
1/19/2012 and
1/30/2012
Is the plumbing at MdL “off limits” to
design changes by the OSU engineering
team?
1/25/2012
1/25/2012
1/18/2012
1/25/2012
Ruth De
Yoe
Ruth De
Yoe
Ruth De
Yoe
Ruth De
Yoe
1/30/2012
Would MdL consider the use of gray
water as a possible technique to
conserve water?
Would a functional biodigestor be a net
positive for MdL? (considering both
benefits and maintenance)
1/25/2012
Ruth De
Yoe
1/30/2012
1/25/2012
Ruth De
Yoe
What is the longest time that the power
has been out? (in a single outage)
1/19/2012,
updated
1/30/2012
What is the cost of electricity per KWh at
MdL? What is the average monthly
electric bill at MdL?
1/25/2012
Ruth De
Yoe
1/25/2012
Ruth De
Yoe
1/25/2012
Ruth De
Yoe
1/30/2012
Possible fuels for a back-up generator for
the lift pump: a.
Confirm the cost
and availability of diesel fuel?
b. Confirm the cost and availability of
gasoline? c.
Confirm the cost and
availability of propane?
When the electricity goes out is the
(lowered) water pressure in the system
adequate to supply MdL’s essential
needs (toilets, showers and sinks including through the drinking water
filters) at least until the (3) primary
storage tanks are empty?
1/25/2012
1/30/2012
Ruth De
Yoe
When the power is out, can the system
access the water in the cistern?
Is it possible to use the 3 primary storage
tanks as a backup supply? (Also see
Question #10)
1/18/2012
Ruth De
Yoe
What is working/not working with the
current filtration system? If needed, can
the current system be expanded?
Ruth De
Yoe
Can we get a digital picture or two of the
lift pump and associated electrical and
mechanical setup inside the
pumphouse? Do you have exact specs
on the pump (brand/model)?
1/30/2012
1/30/2012
Are the two additional water storage
tanks(total ~1000 gal) used for
agricultural purposes an effective backup
supply? Is this water chlorinated?
Ruth De
Yoe
Ruth De
Yoe
1/18/2012
1/30/2012
1/19/2012
1/30/2012
A. 4 days. The length and
frequency of power outages
depends on the time of year.
The cost is approx. 3.25
lempira/KWh. (~17
cents/KWh) The average
monthly electric bill is from
17,000 - 20,000 lempira
or $895- $1,053 (Conversion
rate is 19 lempira per dollar).
All of these fuels are
available, but the cost is
presently unknown.
Primary tanks do not appear
to be used in a power outage.
See Q. # 13 A. The (lowered)
water pressure is adequate
for toilets and sinks, but not
for showers nor for filtering
water for drinking.
See answer to Question #1.
Pressure/flow is low. Lasts
only ~ 1 day. Non-chlorinated
A. Yes, they can be used as a
back-up supply. Water is not
chlorinated, but can be
chlorinated manually.
No, not without power to the
distribution pump.
1/19/2012
A. The primary 3 are used for
that purpose anyway.
Saúl said that the chlorination
system is working just fine;
however, the filtration system
(that we have set up in the
kitchen) is not effective. The
water filters that Erika sent
down in November only
lasted one month; since
December, the water trickles
very slowly through the filters
and it takes an hour, if not
longer, to fill one jug of water
1/30/2012
Pictures sent in advance and
have been put in DropBox.
Picture of pump label
contains exact specs.
1/30/2012
2/2/2012
Ruth De
Yoe
Confirm 1 or 2 backup (diesel?)
generators at MdL. Are they
functional? Take pictures (including mfg
placard with make/model and electrical
specs) or just provide make/model info.
2/2/2012
Ruth De
Yoe
Confirm pressurization tank (near the
cistern pump) does not have a ruptured
bladder. (Procedure descibed in e-mail)
2/2/2012
Ruth De
Yoe
2/2/2012
Ruth De
Yoe
2/6/2012
Ruth De
Yoe
Saul, via
Amanda
Hall
Possible to get a local Honduran licensed
electrician to do, or oversee the
electrical work that we do, for ~ ½ day?
Confirm both main and agriculture
storage tanks used as backup water
supply when power is out. Do
plumbing/valves exist to feed fresh
water from the agriculture tanks back
into the fresh water distribution system?
Is the filling of the two agriculture water
storage tanks (total 1000 gal) done
automatically (or “float-controlled”) or is
it done manually (by opening a valve)? If
it is done manually, how does one know
how much is in these tanks at a given
time and is there a schedule for filling
them?
What is the approximate peak flow
required by the water distribution
system (in gal/min)?
2/6/2012
Saul, via
Amanda
Hall
What is the capacity of the existing
pressurization tank?
2/3/2012
2/3/2012
We still have the two
generators, although neither
are in good condition nor
functional (both are missing
batteries, one needs
additional repairs). The
attached photos provide
additional information. (Both
generators are the same
brand/model.)
Yes, the distribution pump is
wearing out. Saúl insists that
the problem is not with the
pressure tank bladder, but
with the motor for the pump.
We have been using the same
motor for over 10 years and
its estimated life span was 6
to 7 years. He mentioned that
he has a new pressure tank
bladder, but is convinced that
the problem is with the
motor, not with the
pressurization tank.
Saúl is very knowledgeable
regarding electrical work in
general and the electrical
infrastructure of Montaña de
Luz, so he himself can do or
oversee the necessary work.
2/3/2012
Yes, this is correct.
2/3/2012
Automatically.
2/3/2012
2/3/2012
2/6/2012
2/6/2012
(Question not understood.
Clarification being provided.)
Ruth will be sending some
pictures she took of the
pressurization tank, which I
assume lists this information.
(I believe the volume/capacity
is 47.1 gallons.)
2/6/2012
Saul, via
Amanda
Hall
Does the present distribution pump build
up pressure successfully and shut
off? What is the pressure set point for
the system (in psi) at which the pump
shuts off?
2/6/2012
2/6/2012
Saul, via
Amanda
Hall
What is the difference in height between
the intake in the cistern and the
distribution pump?
2/6/2012
2/6/2012
Saul, via
Amanda
Hall
Saul, via
Amanda
Hall
Could we get a few pictures of the entire
pump/cistern system setup (both
electrical and mechanical)?
The 3 main water storage tanks (800,
800, 600 gallons) at MdL appear to
have a lot more capacity (volume)
than what is being utilized. Would it
be possible to set the float control(s)
higher to get more storage volume
than what is presently being utilized
in these tanks? This would give us
more backup capacity during a power
outage.
Saul, via
Amanda
Hall
What is the type of piping (material and
diameter) that connects the main
storage tanks to one another and to the
cistern? Could the existing support
structure and plumbing be expanded
reasonably easily to accommodate an
additional storage tank?
2/6/2012
2/8/2012
2/6/2012
2/6/2012
2/8/2012
Yes; 40 psi
(Roger believes the question
was misunderstood.) This
height is 3-4 feet, but Saul
replied that it was 7-8 meters
which we believe is incorrect.
Ruth will be sending a few
more pictures, but I'm not
sure if they are what you are
looking for. Saúl said that the
electrical setup is really
straight-forward. If you would
like additional photos (other
than the ones Ruth sends),
could you please be more
specific in exactly what you
need? Pics are in Dropbox.
Saúl has already set the float
control(s) higher at least once
in recent years. He said that
he's tried setting them higher,
but the system/tank ends up
throwing out water.
The type of piping that
connects the main storage
tanks to one another and to
the cistern is: PVC pipe, 1.5
inches (diameter). Yes, the
existing support structure and
plumbing could be expanded
to accommodate an
additional storage tank. (Saúl
mentioned HG steel pipes (2.5
inch diameter) connecting the
pump (not sure which one) to
the tanks - but he said that
before reaching the tanks, the
pipes are reduced to the PVC,
1.5 inch pipes.
2/8/2012
2/13/2012
2/13/2012
Saul, via
Amanda
Hall
How much does it cost to get water
brought into MdL during a power
outage? How often does that need to
happen while power is out? What is the
storage capacity of these trucks and
where is the water stored at MdL?
2/8/2012
Saul, via
Amanda
Hall
Would MdL like OSU Engineering to
replace the existing distribution pump?
We would specify, procure, deliver and
install the pump (with input and
oversight from Saul, of course).
2/14/2012
Saul, via
Amanda
Hall
If we were to propose and design an
expansion of the agriculture water tanks
(as an emergency backup for when
electricity is off), could Saul have the
scaffolding/platform built and a poly
tank delivered by the time we arrive?
Would there be enough PVC pipe and
fittings onsite (or easily procured
locally)?
2/14/2012
Yes, of course!
Saúl said that the expansion
of the agriculture water tanks
is not cost-effective. As you
can see in the attached
photos, the
scaffolding/platform for the
agriculture tanks is made of
metal and extremely
expensive and timeconsuming to construct.
While the platform could
perhaps be reinforced to hold
a larger tank (as a
replacement rather than an
addition), Saúl stated that an
expansion of the agriculture
water tanks is probably not
the best option, especially
given that you all head down
to Honduras in just a little
over a month. He suggested
perhaps purchasing a larger
tank (i.e. a tank with a
capacity of 4,000-5,000
gallons) to replace the 3
primary water tanks
(800+800+600=2200 gallons).
He said that the current base
in place could support such a
tank, (3/6/2012 Howard
Comment: Doubtful, since
the full tank weighs > 47,000
lbs.) which would cost
approx. L.25,000 (approx.
$1,350). (3/6/2012
Clarification: A 5800 gal tank
costs approx. $5000 US) He
said that all of the other
materials (PVC pipe, cement
and fittings) can be easily
procured locally.
2/20/2012
2/20/2012
2/20/2012
2/20/2012
2/20/2012
2/20/2012
2/20/2012
Saul, via
Amanda
Hall
What are the current dimensions of the
platform holding the water storage
tanks?
Saul, via
Amanda
Hall
Saul, via
Amanda
Hall
What are the dimensions (largest
diameter) of the storage tanks on the
platform right now?
What materials are used for the main
platform (steel-reinforced concrete?)
and the scaffolding/supports?
In either scenario (installing an additional
tank or replacing the existing tanks with
a single larger volume tank), can the
existing float switch be reused?
Can the pump for the biodigestor be
made available to the OSU team when
we arrive on Saturday (3/17)?
Saul, via
Amanda
Hall
Saul, via
Amanda
Hall
Saul, via
Amanda
Hall
Saul, via
Amanda
Hall
2/22/2012
5.3x2.9m Thickness is
between 6 and 8 inches.
The two 800 gallon tanks
have a diameter of 1.7m (they
are 1.5m tall). The 600 gallon
tank has a diameter of 1.2m
(it is 1.7m tall).
2/22/2012
Yes.
2/22/2012
Yes
2/22/2012
Yes
Can the top of the biodigestor be
removed before we arrive?
2/22/2012
Yes
Does MdL still have wall-patching
material for the tilapia pond?
2/22/2012
2/20/2012
Saul, via
Amanda
Hall
2/27/2012
Saul, via
Amanda
Hall
Can an identical replacement for the Red
Jacket E-Z Prime Jet Pump (distribution
pump) that is currently being used be
purchased in Honduras or do we need to
try to bring a replacement pump with us
and get it through customs?
What is MdL's approximate annual cost
on chlorination? If you don't know the
cost, then what is the annual usage of
chlorine tablets.
Saul, via
Amanda
Hall
Does MdL have a water testing lab in
Honduras to which they have sent
samples for analysis? If so, what is the
name of the lab and what is the cost per
test?
2/27/2012
2/22/2012
2/22/2012
2/28/2012
2/28/2012
No, we no longer have wallpatching material.
Saúl says that an identical
replacement (Red Jacket
Pump) would have to be
purchased in the US, but that
there are a couple
comparable models that can
be purchased here in
Honduras.
Approx. 2,000 lempiras
(approx. $100)
Yes. Saúl believes the name of
the lab is something along the
lines of "Laboratorio
Químico," but he is not
exactly sure of the name. He
said the cost per test depends
on the type. While one test
costs approximately 1,600
lempiras (approx. $85), more
extensive tests cost 2,000
lempira or more ($100+). Saúl
said that while we used to do
more regular testing of our
water, we haven't sent a
sample for several years.
2/27/2012
2/27/2012
3/1/2012
Saul, via
Amanda
Hall
Saul, via
Amanda
Hall
Saul, via
Amanda
Hall
About how many gallons of filtered
water does MdL use per day?
Would you get several digital pictures of
the current filtration system and its
connection to the plumbing?
Does Saúl have a method to get the new,
larger tank on the existing platform?
2/28/2012
2/28/2012
3/2/2012
Approximately 15 gallons (3
5-gallon jugs)
In Dropbox
Yes. Howard Comment
3/6/2012: Doubtful, since
the tank weighs > 1000 lbs.
3/1/2012
Saul, via
Amanda
Hall
What are the specifications on the new
poly water tank that he is planning on
buying in Teguc? Gallon capacity,
Dimensions (diameter, height), Lead
time, Price confirmation
3/2/2012
3/1/2012
Saul, via
Amanda
Hall
Does MdL have plans for what they
would like to do with the old (3) tanks?
3/2/2012
Saul, via
Amanda
Hall
What is the material and size of the
plumbing underneath the faucet that has
the drinking water filter? Is it 1/2" PVC?
Could we get a picture or two of this
plumbing under the cabinet?
3/2/2012
Saul, via
Amanda
Hall
Does MdL have 1" and 1-1/4" pipe stock?
If not, can this be obtained easily? We
anticipate that a few feet of spare pipe
will be necessary for the installation of
the new distribution pump.
3/13/2012
More detailed information
regarding this question will
arrive 03/02/2012 after Saul
gets an estimate in
Tegucigalpa
Tentatively, the two larger
tanks (800gallons) could
replace the water tanks at the
two staff houses in Nueva
Esperanza. The current tanks
down below are significantly
smaller and we consistently
run out of water each week.
Saúl said there aren't any
specific plans for the other,
smaller tank. It could either
be utilized elsewhere at MdL
or sold.
PVC, approx. 1". (Howard:
Needs clarification. I think
this is 1/2" ID) Pictures
should arrive on 3/2/2012
and be posted to Dropbox
shortly thereafter. 3/6/2012
Clarification: 1/2" ID, pics in
Dropbox
Saúl said that we do have 1"
pipe stock in our inventory,
but not 1-1/4". I have
requested that he check at
the ferretería to see if they
carry 1" and 1-1/4" pipe
stock. Regardless, we will plan
to purchase 2 ft. of each size
before your arrival. (Howard:
We will purchase all PVC pipe
needed.)
Saul, via
Amanda
Hall
Does MdL have the ability to cut normal
pipe threads on 1" and 1-1/4" pipe
stock? If new pipes are needed for the
distribution pump installation the new
pipes will need to be threaded so that
they fit into both the pumps and the
3/13/2012
Saúl said that we do not have
this capability, but that prethreaded PVC can be
purchased. Is that correct? If
so, should pre-threaded 1"
and 1-1/4" PVC be
3/1/2012
3/12/2012
3/12/2012
elbows or Ts on either side.
purchased? (Howard: We
will purchase all PVC fittings
and pipe needed. PVC
fittings are pre-threaded)
APPENDIX G: BILL OF MATERIALS
Category
Item
Price
Notes
Instructional Posters
Cardstock
$5.50
Pack of 150
Plastic Frames
$17.00
Set of 6
Caulk
$5.00
9.8 oz
Caulk Gun
$6.00
Standard size
Pencils
$4.00
Pack of 12
Pencil Sharpener
$3.00
WalMart
Colored Sharpies
$7.00
Pack of 12
Zip Ties
$7.00
Pack of 100
Scissors
$5.22
Packof 2
Influent
Manure
Honduras
Measuring Tools
Tape Measurer
Ohio State
Gas Pressure Gage
$5.00
Hardware
Store
Water Testing
pH Test Strips
$13.00
WalMart
Labor Tools
Bucket
On site
Rope
On site
Shovels
On site
Pump
Sump Pump
On site
Protective Gear
Gloves
$12.00
WalMart
Reuse Grocery Bags
From the
Team
Face Masks
$7.00
WalMart
Tilapia Repairs
Concrete Patching
$25.00
Hardware
Store
Biodigester Gasline
1 ½ Inch Universal
Valve
Obtained in
Honduras at
their Hardware
Store
3 ½ Inch Female
Threaded Couplings
Obtained in
Honduras at
their Hardware
Store
2 ½ Inch Ts
Obtained in
Honduras at
their Hardware
Store
6 ½ Inch Male
Threaded Couplings
Obtained in
Honduras at
their Hardware
Store
2 ½ Inch Valves
Obtained in
Honduras at
their Hardware
Store
2 Couplers
Obtained in
Honduras at
their Hardware
Store
3 Elbows
Obtained in
Honduras at
their Hardware
Store
43 Feet of PVC
Obtained in
Honduras at
their Hardware
Store
Total for Gasline
$50.00
Total
$171.72
APPENDIX H: BIOGAS PRODUCTION ANALYSIS
(Used volume of biogas produced per ton in previous calculations; chart obtained from Rachel
Childers)
APPENDIX I: MANURE PROCURED ANALYSIS
APPENDIX J: INITIALIZATION VOLUMES ANALYSIS
APPENDIX K: HELPFUL SPANISH WORDS AND PHRASES
Helpful Spanish Words and Phrases

Compost-Montón de compost or mantilla

No meat or bones- no carne o hueso

Fruit- las frutas

Vegetables- las verduras

To produce gas for cooking- producir gas por cocinar

Add everyday- añadir cada día

Water – agua

Fish – pez

Pump – la bomba de agua

Cement- cemento

Month- el mes / los meses