Aquaponics System in Choluteca, Honduras
Post-Trip Documentation
Trip: May 4 – May 18, 2013
Submitted May 23, 2013
Emmy Schroder
Matt McCracken
Nikki Pangilinan
Jared Stayer
Chelsea Dailey
Justin Letts
Table of Contents
Post-Trip Documentation.................................................................................................................................. 1
Abstract .................................................................................................................................................... 3
Background Narrative ......................................................................................................................... 3
Team Roles .......................................................................................................................................................... 4
Stated Scope of Work ........................................................................................................................... 4
Fish and Plant Research ...................................................................................................................... 5
Water Quality.......................................................................................................................................... 5
Research/Design/Build/Prototype/Test ..................................................................................... 6
Determining power usage and equipment needed ......................................................................................... 9
Estimated Trip Schedule: (1~10days) .................................................................................................... 13
In country Implementation ............................................................................................................. 14
Implementation/ Installation ................................................................................................................... 14
Issues Encountered ....................................................................................................................................... 18
Testing results ................................................................................................................................................ 22
List of Supplies/materials given to the “Customer” .......................................................................... 25
Trip Timeline ........................................................................................................................................ 26
Objectives achieved/ Deliverables .......................................................................................................... 28
Final Cost Analysis ......................................................................................................................................... 31
Conclusions regarding the project and technologies ............................................................. 31
Recommendations .............................................................................................................................. 31
Acknowledgements ............................................................................................................................ 32
Appendix A: Power calculations .................................................................................................... 33
Appendix B: Materials List ............................................................................................................... 34
Appendix C: Equipment Specifications ....................................................................................... 35
Solar panels ................................................................................................................................................................... 35
Battery ............................................................................................................................................................................. 37
Pump ................................................................................................................................................................................ 38
Appendex D: Maintenance Instructions left in Honduras ..................................................... 39
Appendix E: References .................................................................................................................... 42
Appendix F: Team Agreement ........................................................................................................ 44
Appendix G: Product Manuals ...................................................... Error! Bookmark not defined.
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Abstract
The purpose of this project is to design and build a fully functioning and solar powerdependent aquaponics system to the Escuela Tecnica (Technical School; vocational school) in
Choluteca, Honduras. The last aquaponics system that was developed in 2011 is no longer
functioning. The new system will be sustainable and the students and staff at the school will have
complete ownership of the system. Aquaponics systems consist of two different types of tanks, a
fish tank and one or more grow beds. Water in the system is cycled through so that the plants in
the grow beds are fertilized and the water in the fish tank is cleaned. The ultimate goal is for the
system implemented in Choluteca to be completely self-sustained and used as a learning tool at
the school.
Background Narrative
Beginning in 2010, ECOS, Dr. John Merrill, and the Office of International Affairs at
The Ohio State University have pursued an interest in coordinating and implementing
humanitarian engineering projects in Choluteca, Honduras. A team was sent in 2010 to research
and assess the area. This year, the Aquaponics group containing 6 students led by Roger
Dzwoncyzk and Miriam Cater, aims to implement a new aquaponics system at the vocational
school located in Choluteca.
Aquaponics is a sustainable food production system that combines raising aquatic
animals such as fish, with cultivating plants in water through one symbiotic environment. Using
only solar power, the overall goal of the system is to provide enough energy to pump water from
the fish tank to the plants. By doing so, a self-sustained system, capable of producing fruits,
vegetables and fish, is obtained. In recent years, a successful aquaponics system has been
constructed at World Gospel Mission run by Larry Overholt in Choluteca. However, the
3
aquaponics system recently built at the school is no longer functioning because the fish died,
most likely due to a bad ratio of fish tank to grow bed water volumes. Also, the wood began to
deteriorate, so the grow beds will also need replacing. The purpose of this system was to educate
the students at the school. The new system to be implemented this year will also run completely
on solar power, but will be larger, and more durable. We also hope to deliver full ownership of
the system by the staff and students at the school.
Team Roles
The team members and their roles in the project can be found in the table below.
Role
Team members
Email
Phone
R&D
Chelsea Dailey
dailey.156@osu.edu
740-815-1143
Treasurer
Matt McCracken
mccracken.89@osu.edu
419-346-5019
Communicator
Justin Letts
letts.5@osu.edu
330-321-7345
Documenter
Nikki Pangilinan
pangilinan.2@osu.edu
703-927-1457
Leader
Emmy Schroder
eschroder.15@gmail.com
513-602-8812
Scheduler
Jared Stayer
stayer.3@osu.edu
330-461-2730
Stated Scope of Work
The main objective of the project is to deliver a fully functioning aquaponics system to
the vocational school in Choluteca. The current aquaponics system no longer holds fish and is
deteriorating due to the weather and the materials used in its construction. The new system will
be completely solar-powered and will sustain about 15-20 tilapia at a time.
4
The fish pond will be built into the ground so that it will last longer, and the grow beds
will be constructed from wood plywood but will be protected with durable waterproof pond
liner. The system will be completely self-sustained as the energy will all come from the sun, and
it will be left with a detailed set of instructions for maintenance. The system will be used as a
teaching tool for the students at the school and the students and staff at the school will be able to
take complete ownership of the system and take care of it.
The main goals of this project are based on the needs of the customer that we have
learned via Larry Overholt. Per his request, the budget of the entire project should be around
$400. The system must be reliable and durable, located in a useful location, and be maintainable
with minimal work. The customer should also be able to replicate the system if needed with
minimal investment.
Fish and Plant Research
Based on the research from the 2011 documentation, it was decided that tilapia would be
the best choice for our fish tank. Tilapia are the second most cultured fish in the world because
they are easy to breed, grow fast, and can withstand range of water conditions. They have an
omnivorous diet which is necessary for an aquaponics system and like warm water. Of the
researched species, these were the most practical.
Suggested plants for growing in Choluteca, Honduras recommended for easy growth and
productivity are: tomatoes, cucumbers, spinach, radishes, lettuce, herbs, and celery.
Water Quality
In aquaponics systems the fish and plants are dependent on the balance of dissolved
nutrients and quality of the water, as they generate and utilize metabolic products from each
5
other. Through the release of nutrients from fish to plants, periodic monitoring of the system’s
water is essential. The chemicals monitored are ammonia, oxygen, nitrite, and nitrate which all
comprise the nitrogen cycle. A diagram of the nitrogen cycle within an aquaponics system can
be found in Figure 1 below. Temperature of the water and its pH are also recorded. Keeping the
pH, temperature, and chemical levels within their respective safe ranges will ensure the health of
the fish.
Figure 1: Nitrogen Cycle
There are a multitude of available testing water systems ranging from water test strips
and kits to electronic meters. The 2012 aquaponics team purchased multiple items for water
testing which will be reused this year. The items purchased include nitrate/nitrite water test
strips, a mini lab oxygen test kit, and a refill kit. With these materials the water testing for the
aquaponics system will be accomplished.
Research/Design/Build/Prototype/Test
Many different setups were considered when designing the overall system. The goal was
to build a system that could sustain 15 tilapia, and each tilapia was estimated to be about 3
pounds. The aquaponics gardening community recommends at least 5-7 gallons per pound of
fish, so it was decided that the fish pond should hold 450 liters of water. The grow beds are
6
recommended to hold twice as much volume as the fish pond, so in total, about 900 liters of
grow beds were calculated to be required. The main problem was the physical design of the
grow beds that would hold the desired amount of water.
Many different designs were considered with varying materials and sizes of grow beds
were considered, it was decided that the best design included four grow beds, each of about 250
Liters. The water from the fish pond would be pumped and split into two grow beds, each of
which would then siphon into another grow bed before siphoning back into the fish pond. See the
layout in Figure 2 below. A model of one constructed grow bed is shown in Figure 3 below.
Fish tank 450L
Figure 2: Layout of the aquaponics tank and grow bed system.
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Figure 3: Design of the grow bed with supports.
The circulation of the water flow in the aquaponics system was one of the problems
encountered. A submersible pump was chosen to move water from the fish pond to the grow
beds. The procedure used to choose this pump is described in the next section, entitled
“Determining power usage and equipment needed”. Based on the layout of the system, the
possibility of using two pumps to move water into each column of grow beds was considered,
but this idea was rejected based on power requirements. This created the problem of how to
divert half of the pump’s water flow into each grow bed column. Hose wire was attached to the
end of the vinyl tubing leading from the pump, and a valve was attached to each branching
stream. These valves were used to control the water flow rates entering each grow bed
column. After the water level in each top grow bed reached a certain point, a bell siphon would
empty the water into the grow bed underneath. This same procedure was then used to move
water from the bottom grow beds to the fish pond.
The proper dimensioning and design of the bell siphons was another problem. According
to the University of Hawaii, 1/2” ID pipe is proper for a grow bed of 4 ft3 while 1” ID pipe is
8
proper for a grow bed of 16 ft3. With grow beds of 8 ft3, it was decided that 3/4” ID pipe would
be proper for the system. A picture a disassembled bell siphon is shown in Figure 4 below.
Figure 4: Picture of a disassembled bell siphon.
Determining power usage and equipment needed
The flow rates of the pump and siphons were determined so that none of the grow beds or
the fish pond would overflow. The first pump purchased moved 20 gallons of water per minute,
and the siphons would not circulate the water downwards nearly fast enough. Additionally, after
testing the output current drawn by the system, the power required to run the pump was greater
than the solar power output. This pump was deemed too powerful for the size of the fish pond
designed, so it was decided that a new pump would be purchased for a reduced flow rate. The
water must be cycled through the system at least once per hour for the water to be cleaned
sufficiently and for the plants to be well fertilized and watered.
It was then decided to buy a submersible pump capable of moving 620 gal/hour. 360
gal/hour of water must be moved, and thus the pump could be run at a 50% duty cycle. See Table
2 for details on the power calculations.
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In order to determine the power needs of our solar panel sets, a set of assumptions and
calculations was made to ensure that the battery was large enough, and that there would be
enough power to charge the battery and run the pumps. The system was designed to run for three
days on one fully charged battery with no sunlight. For power calculations, each day was
assumed to have eight hours of sunlight. Assuming that the pump will be run at a 50% duty
cycle, and that it will only consistently draw 75% of its rated current output (.435A) while
running, the solar panels will be required to produce 78.3 Watts. As the solar panels are rated up
to 45 Watts each, an adequate amount of power will be produced. The assumption that the pump
will not draw its full current is made based on testing of the first pump that was bought, which
only drew about 60% of its rated current usage of 2.5 Amps. Refer to Appendix A for specific
calculations on the panel power needs. Once the second pump was purchased, the current output
was measured and this assumption proved accurate.
An improvement that our team decided to make on the electronic system was to change
the output energy from direct current (DC) to Alternating current (AC) at the output. This reason
we believe this to be an improvement is because AC sourced power is much more versatile and
replaceable in Honduras. Price analysis on the comparison between the AC and DC options
showed similar pricing considering that a DC timer costs about $65 whereas we obtained an AC
timer for $7.44. Buying the inverted was an additional $26, but will make the system much more
sustainable.
Another project that was adopted was on the aquaponics system that is in place at the
World Gospel Mission clinic. This system has been functioning completely on grid power since
its installation. There is an option to switch to solar power, but construction in the near future
will require the solar panels to move from their current location. The team plans to assess the
10
area to figure out the best way to implement the solar panels at a different location, cutting down
energy costs. It has been suggested that the solar panels be moved to a lower roof, but it is
currently made of corrugated fiberglass so it needs to be replaced before the solar panels can be
properly secured.
Table 2. Pump Power Calculations.
A diagram of the entire electrical system configuration can be seen in Figure 5 below. As
shown, each solar panel will be connected to its own charge controller. These will feed into the
DC battery that is currently in use at the vocational school. The battery will feed into the
inverter, then the timer, and into the pump. For a complete list of equipment, with specifications,
refer to Appendix C. For all other parts and equipment purchased, refer to Appendix B.
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Figure 5: Planned Electrical System
Figure 5: Layout of the electrical system.
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Project Schedule - Aquaponics
1/17 1/31 2/14 2/28 3/14 3/28 4/11 4/25
Team Agreement
Project Proposal
Research
Cost Analysis
Design/Build Processes
Test Results
Supplies/Equiptment Acquistions
Pre-Trip Presentation
Pre-Trip Documentation
Final Presentation
Final Documentation
Estimated Trip Schedule: (1~10days)

Gathering of materials needed to be purchased in Honduras (1,  10)

Construction of grow beds (13)

Set up of solar panels (24)

Implementation of pond liner in grow beds (34)

Construction of siphons in grow beds (45)

Water testing (56)

Complete whole system (adding all steps together) (710)

Trouble shooting, problems that come about while in Honduras (710)
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5/9
5/23
6/6
In country Implementation
Implementation/ Installation
Because of the availability of wood at the vocational school, including several
wooden pallets, the original grow bed design including sheets of plywood was revised. The
four wooden pallets of highest quality were chosen as grow bed bases. The boards from
the remaining pallets were cut into thin strips to fill the gaps in the four bases.
Because of the size constraints introduced by using the pallets as bases, the original
24"x48"x12" design was also revised. To maintain the same approximate fish pond volume
to grow bed volume ratio, grow beds of 30"x38"x12" were chosen. To increase the
durability of the grow beds, 1"x4" boards were used to make the sides of the grow beds
rather than plywood. It was calculated that 17 sections, each 8' in length, were needed for
construction. 18 of the sections were purchased to provide for damaged sections of lumber
and future needs. Because of the 4" width of the boards, three boards were built up the
sides of the grow beds to achieve the desired 12" height. A picture of a finished grow bed
pallet base and the construction of the sides of the grow bed can be found below in Figure
6.
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Figure 6: Grow Bed Construction
The rubber pond lining itself was used to line the inside of each grow bed and
wrapped around the outside of the grow bed. The excess liner wrapping around the
outside of each grow bed was attached to the wood using staples. The liner itself was found
to be of adequate thickness to serve as a rubber gasket and seal the grow bed from leakage,
so the rubber o-rings were not used in mating the siphons. The base of each grow bed was
found to be too thick to mate the siphons without some recess in the base boards. A 1 1/2"
spade bit was used to make a recess through the bottom of the grow bed at the desired
siphon location, and then a 1" spade bit was used to drill the remainder of the hole through
the top. This 1" hole, after being slightly enlarged with a file, allowed for the male threads
of the siphon to drop through the grow bed base, and the 1 1/2" hole allowed for the entire
female adapter to insert from the bottom of the grow bed and meet the male threads of the
siphon. Silicone RTV gasket maker was used to seal the PVC of the siphon to the rubber
grow bed liner.
A PVC elbow was glued to the female adapter and a further section of PVC was
added to this elbow, allowing for each grow bed to drain into the level below. Water
15
draining from this horizontal PVC section in each top grow bed was found to splatter too
much upon landing in the grow beds below, and thus another PVC elbow was attached to
each section and a short vertical piece of PVC was added into this elbow to drain the water
directly onto the gravel with minimal splatter. Each piece of PVC was attached using PVC
cement. The back of each grow bed was raised with extra sections of 1"x4" wood to force
the water in the grow beds to naturally flow out the siphons.
The wye splitter made in the United States was put together using Teflon tape
attached to the vinyl tubing with a hose clamp. The splitter itself had to be mounted to the
grow beds, and so a new design was needed. To keep the modular design of the entire
system, the wye mounting system could not be attached to the grow beds permanently.
The wye itself also had to be removable from the mounting system. Two extra sheets of
1"x4" wood were used side by side, and attached to each other using other small pieces of
wood. The vertical piece of wood on one side was raised slightly to account for the fact that
one grow bed was a fraction of an inch higher than the other. Two holes were drilled
through the side of each vertical section, so that rebar could slide between the vertical
sections. The two holes were located such that the rebar would slide between the valves
and female threads of the wye splitter, effectively locking the splitter into place. The
wooden structure itself was set onto the back of the grow beds, between the two grow bed
columns. Small sections of wood were screwed behind each side of the mounting system,
keeping the system in place. The entire mounting system is easily removable by removing
the top section of rebar and the wye splitter, followed by simply lifting up on the mounting
system. A picture of the finished mounting system can be found below in Figure 7.
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Figure 7: Splitter mounting system.
Fish Pond Overflow
In the event of high rainfall, the fish pond would overflow. Also, dirt would be
washed into the fish pond by rainfall as the top of the concrete pond was nearly flush with
the ground. An extra three inches of concrete were added to the top of the fish pond to
protect against splatter. Also, a length of extra PVC was laid into this new concrete with a
mesh filter around the end as an overflow release pipe. This pipe was laid along a
downward slope dug into the ground away from the pond. Rocks were gathered and piled
into the trench to keep dirt from clogging the pipe. The overflow trench was later extended
further down a natural slope to prevent pooling of the overflow water. A picture of the
overflow pipe can be found below in Figure 8.
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Figure 8: Fish pond overflow pipe.
The implementation of the new electrical system and solar panels involved some slight
plan changes and innovations from the original design. As was planned, an additional set of solar
panels was brought from the U.S. to add to the existing set. Although the new panels are the
same modal as the old ones, some modifications had been made as updates to the hardware.
It was decided that all solar panels should be relocated onto the roof of the vocational
school. This required the purchase of conduit to run down the wall and under the cement as well
as extra labor to ensure that the panels are secure and efficient. More discussion on the reasons
for this decision can be found in the issues encountered section. Some leftover cables were used
to extend the solar panel wiring from the roof down to be connected to the charge controllers.
Issues Encountered
One of the first issues encountered was the original system that had been
implemented the previous year. Much of the first day was used to assess the system and
tear it apart while trying to save parts, such as the gravel and some pieces of wood, to use
later in the week. The time spent on this was longer than expected because in addition to
18
the system the fence that had been constructed around it also needed to be torn down.
This required help from local workers and special tools, and it had to be done before
breaking down the old system because the space around it was not enough to effectively
remove the system.
Lastly, the setup of the grow beds was a problem because they took up almost all of
the room on the concrete platform that was surrounded by the fence, leaving no room for
the solar panels. Additional concrete was mixed so that three more feet of space was added
to the back of the platform. Although the plan to keep the solar panels was later changed as
will soon be seen, the space was used to add a bench behind the top grow beds so that the
users would have easier access to the entire system.
As it was not recognized that the solar panels were different than the year before, there
were a few problems to be overcome. First, the framing for the new system was made up of ¾’’
PVC piping. This structure was much less sturdy and was not a good option for leaving the
panels on the cement ground within the fence. Our first option was to build our own stand for the
new panels, and set them up next to the old panels on our new extended cement platform. The
old panels were set at an angle of about 35 degrees from the horizontal. Although this angle
seemed to work, we found from our research that a smaller angle (between 5 and 15 degrees)
would have been optimal based on our location just 5 degrees from the equator (Backyard
Aquaponics). A smaller angle would give a more direct angle for the sun to reach all year long.
This option would be easier to install, but could pose more security threats as they would only be
protected by a fence. The second option suggested was to move the panels to the roof of the
vocational school right in front of the aquaponics system. This placement of the panels would
allow a smaller angle of incidence (between 5 and 10 degrees), and would allow the panels to be
19
safe from tampering and secure. Despite the extra work and a small extra cost due to the conduit
and wiring that had to go under the concrete, the panels were moved to the roof.
Another issue that was encountered during the installation of the conduit occurred when a
water main was cracked by our crow bar. In order to resolve the problem, the water was shut off,
the PVC water line replaced, and the conduit bend to go around the existing line.
Once the wiring was complete, the pump was switched over to solar power from the
battery. At this time, the battery was reading 11.8 Volts and ran the system. After a few minutes
of running, the inverter alarm sounded. After recharging the battery and testing the battery from
the wind generator project, it was found that both batteries were ineffective. Because the solar
panels at the clinic are not currently being used, 2 identical deep cell 12 Volt new batteries were
available to us. Once these batteries were used to replace the old ones, the inverter alarm shut off
because the battery was fully charged and the system functioned.
Finally, the schematic of the electrical system was slightly altered from the planned set
up. Instead of plugging the inverter into the battery, it should have been plugged directly into the
charge controllers as can be seen in Figure 9 below.
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Figure 9: Updated Electrical system
21
Testing results
Siphon
Once the four decline-leveled grow beds were constructed, the pond liner with the
bell siphons installed, and the gravel shoveled in, the siphon testing was ready. With rain
water already in the pond and the submersible pump in place the testing began. The first
and every other siphon test throughout the week cycled perfectly from one grow bed to the
next and back into the pond with ease. At first one grow bed was receiving much more
water than the other causing the siphon to start quicker. To fix this problem the valves
were adjusted at the top so that each grow bed received an equal amount of water. The
pump was left on throughout the week in fifteen-minute increments allowing the siphons
to be tested more and it was apparent that the siphons provided high oxygen and access to
nutrients for the plant roots and also began cleaning the water. Shown below in Figure 11
is a picture of the siphon test working properly.
Figure 11: Photo of a siphon test
22
Water Testing
Once the aquaponics system with fish and plants included was finished, water
testing of the pond began. The water testing was comprised of TH, alkanity, pH, nitrite,
nitrate, oxygen, and temperature. The data was taken twenty-four hours after the fish and
plants were inserted into the system. The figure below displays the water testing data
collected.
Table 3: Water Testing Results
Test 1
Test 2
TH, hardness (ppm)
Alkanity (ppm)
pH
No2, nitrite (ppm)
No3, nitrate (ppm)
O2, oxygen (drops)
Temperature (°F)
120
140
7.5-8
0
0
10
85
Test 3
80
140
7.5-8
0
0
11 ----85
120
150
8
0
5
85
Tilapia is the most widely cultured fish in the world and can tolerate a wide range of
water conditions. The tolerance levels for tilapia are listed below.
Table 4: Tolerance Levels for Tilapia
Tolerance Levels for Tilapia
TH, hardness (ppm)
Alkanity (ppm)
pH
No2, nitrite (ppm)
50-350
50-250
7-8
0.0-0.8
No3, nitrate (ppm)
0-300
O2, oxygen (drops)
7.8-
Temperature (°F)
Ammonia (ppm)
64-90
0.0-0.4
23
(Nelson)
From the tables above, hardness, alkanity, pH, nitrite, nitrate, and temperature all
fall into the safe ranges for tilapia after one day in the pond. The testing of oxygen was
through a titration and measured in drops of a substance. The ideal number of drops was
7.8 and above, which is within the tolerance level of oxygen for tilapia. Presumably the
ammonia level would be about zero because the fish had just been introduced into the
system, so it was not tested.
Drainage Testing
Draining of the pond consisted of two separate tests. Test number one occurred on
the first draining system, which was created by digging up dirt where the PVC pipe
connected to the pond on a declined slope. The extra trench area was filled with large rocks
so the pipe did not clog up with dirt (see Figure 12 below). After adding water to overfill
the pond, the drainage test was successful but the volume filled quickly. With the Honduran
wet season, the team felt the aquaponics system needed to add more volume for drainage.
To accommodate this, a trench was dug up along the natural declined slope parallel to the
aquaponics system (see figure 13 below). The trench was filled with gravel and tested. Test
2 was very successful and the trench filled up slowly with volume still available.
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Figure 12: Initial drainage trench
Figure 13: Secondary Drainage Trench
List of Supplies/materials given to the “Customer”
There were a number of materials left to the vocational school as resources for up
keeping the new system. These materials include:

Fish food donated by Larry Overholt and WGM

A homemade red framed strainer netting to remove solids from the top of the fish
tank

An extra battery located in the bodega with an “O” on it in case it is needed back at
the Overholts or as a replacement to the current one

Additional seeds were left at the clinic in the possession of the Overholts

Instructions for use and maintenance of the Aquaponics system were left with Tim
at the school and with Larry Overholt at the clinic
25
Trip Timeline
Saturday, May 4th:
 Traveled to Honduras
 Drove to Choluteca from Tegucigalpa
Sunday, May 5th:
 Beach day
 Church service at Shalom (optional)
Monday, May 6th:
 Tore down previous aquaponics system & some fencing
 Constructed four grow bed bases
Tuesday, May 7th:
 Completed the four grow beds
Wednesday, May 8th:
 Put grow beds into place with cinder blocks on a declined slope
 Removed dirt mound in front of system
 Installed pond liner into each grow bed
 Installed four siphons into each grow bed
Thursday, May 9th:
 Created custom made frame for Y-splitter above grow beds
 Painted the four grow beds scarlet & gray
 Removed the rest of the fencing surrounding system
 Constructed the new solar panels
Friday, May 10th:
 Painted the water sealer over grow beds
 Drew “O-H-I-O” into the side of the grow beds
 Shoveled in the gravel into each of the grow beds
 Mixed up and laid down concrete for the extra three feet added on to the back of the
system to allow more space
 Began construction of new solar panel frame
 Started building housing for the charge controller
 Began siphon testing
Saturday, May 11th:
 Took a tour of the area of Choluteca where Angie & Larry live
 Traveled to down town Choluteca for shopping & site seeing
 Visited the capstone aquaponics system located at Siete de Mayo & got to experience
the local children at their school
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Sunday, May 12th:
 Church service at Shalom (optional)
Monday, May 13th:
 Added four inches of concrete to the pond in case of heavy rainfall
 More siphon testing
 Began preparing the wires and conduit for the solar panels on the roof
 Welded a metal frame for a solar panel base for the previous solar panels
 Began digging for the underground conduit
 Cleaned pond water
Tuesday, May 14th:
 Finished draining system of the pond
 Installed both solar panels onto the roof
 Built a container for the inverter
 Installed fish & plants into the system
Wednesday, May 15th:
 Planted all the seeds in the grow beds
 Built four poles cemented into the ground with some of the fencing around the
system
 Built step stool/bench to allow access to back grow beds
 Completed the conduit wiring of the system
 Tested the water
 Tested the draining system
Thursday, May 16th (last day of work):
 Finished fencing around system
 Obtained good unused battery for the system from the clinic
 Created an instructions manual for the system to Larry & Tim
 Created the tarp for shade of the fish pond
 Cleaned up area
Friday, May 17th:
 Traveled back to Tegucigalpa to stay in the WGM house
 Traveled to Valle de Angeles for shopping
Saturday, May 18th:
 Returned home
27
Objectives achieved/ Deliverables
A fully equipped aquaponics system, working solely off solar power has been built at
the location of the vocational school in Honduras. The model was created using almost all
locally available material, most of which were scrap material. The system is easily able to
run off the grid, or from two solar panels located on the roof, powering the pump and timer
at a 50% duty cycle.
Figure 14: The fully equipped
aquaponics system
Figure 15: Solar panels located on
the roof
he four wooden grow beds were built from
locally available materials. The bases were constructed using wooden pallets and extra
wood found in the back of the vocational school. The wood was added on to the pallet so
the gravel did not slip through the cracks. The front two grow beds were put onto cinder
blocks on a declined slope so the water would flow correctly. The back two grow beds were
put on top of a metal framed table on a declined slope as well. The table made out of metal
was previously located as Larry’s house having no use. The pond liner was bought in the
U.S. but a similar model might be found in Honduras. The liner was able to wrap around the
28
T
grow beds with ease and could withstand tearing after gravel, plants, and water were
added into the system.
Figure 16: Construction of the grow
beds
Figure 17: Installation of the pond
liner within grow beds
Four siphons for each grow bed, the submersible pump, the two valves, and tubing
was purchased in the U.S. but can all be found at the local hardware store. The Y-splitter
located in between the top two grow beds, purchased in the U.S. could be hard to find in
Choluteca but found easily in Tegucigalpa. A custom built wooden frame with rebar kept
the tube and Y-splitter above the grow beds and could be removed easily in case of
emergency. The frame was made from scrap material located at the vocational school.
29
Figure 18: Custom built frame for tubing and the Y-splitter
The gravel was collected from a nearby river after being sifted. The gravel from the
old system was also reused. The fish and plants were imported in from Larry but can be
easily found in Choluteca. The two solar panels were set on a custom welded metal stand,
which was also built from scrap materials. The wiring from the solar panels to the system
was built from local available wires and conduit. The draining system located to the left of
the pond was created from local materials such as gravel and PVC pipe. The previously
used battery was worn out so the team obtained the unused battery from the clinic to be
used for free. A custom-made container made out of an old water jug and pond liner
secured the inverter and timer. An old wood box constructed by the 2011 aquaponics team
was used to house both charge controllers in one place. The timer runs on fifteen-minute
intervals to allow for the battery to have time to charge while the system receives adequate
filtering. A fence was installed around the entire system in case of theft and to keep animals
away from the pond.
30
Final Cost Analysis
The final project cost was $657.72. The original predicted cost was $506.79. The
disparity in these values was caused by design changes needed in Honduras and the parts
needed for these changes. For example, the design of the grow beds was altered to use
1"x4" boards rather than plywood as the walls of each bed. Design changes also allowed
for some savings. Pallets found at the vocational school were used as grow bed bases,
eliminating the need for additional lumber purchases. The $657.72 total reflects the actual
cost of the system, as all purchases were used for the final system. First prototypes were
made with items already possessed, and subsequent prototypes were eventually used in
the final system. An itemized list of all items purchased can be found in Appendix B.
Conclusions regarding the project and technologies
In conclusion, a working aquaponics system was delivered to the vocational school
on Choluteca, Honduras to be used as a learning tool for the students there as well as a
minor source of herbs, tilapia, and vegetables. The goals of the project were met because
the system runs only on solar power and sustains 15-20 Tilapia. The entire project ended
up a little more expensive than initially forecasted, but with a final cost of ###.
Recommendations
The goal for the future of the Aquaponics project is to continue developing a model
that can be constructed 100% locally and affordably. The system could then be replicated
by Larry and Angie, or by an interested Honduran to create a sustainable business and food
source for the community. In order to accomplish this, solar panels could be purchased
from a store called “SOLAIRES” in Choluteca. However, the cost is still greater than those
31
from the United States. These differences should be investigated more by future groups.
Additionally, in order to be reproducible, a local method to line the grow beds will be
needed. This method could involve a local source of a pond liner, returning to the idea of
creating concrete grow beds, or using some other material.
Although our energy generation from the solar panels calculated out to be adequate
for the power requirements to cycle the water once per hour, we would recommend
performing an energy study on the panels’ energy generation in relation to the power
consumption from running the pump at 50% duty cycle. This could be obtained by
measuring the soar output over a longer time frame and comparing it with the pump
consumption over the same time frame. If the results show a large deviation from our
calculation, proper adjustments could be made to the system.
Finally, if there is a lingering problem with the alarm on the power inverter
sounding due to low voltage in the night, the alarm could be removed from the inverter.
From the results produced this year, we hope that this system does not need further
improvements right away, but future groups could move on to a new location with further
recommendations and advice from Larry Overholt and Jose “Chacho” Davila.
Before a future project begins construction planning, the group should obtain a
listing or set of photos of the area, resources, and materials that will be available for usage.
This may cut back on plans that will be altered upon arriving into Honduras.
Acknowledgements
•
Roger Dzwonczyk (daily support)
32
•
Miriam Simon (daily support)
•
Larry Overholt (created opportunity for this project, guidance and foreign liaison)
•
Angie Overholt (created opportunity for this project, guidance and foreign liaison)
•
Dr. John Merril (created opportunity for this project)
•
Maintenance Individuals
•
Customers: Local community
•
Dr. Peter Rogers (Class Resources)
•
Patrick Bosch (Lab oversight
Appendix A: Power calculations
Using the current measured from our running pump, the power used by the pump is:
𝑃 = 𝐼𝑉
𝑃 = (0.25 𝐴)(120 𝑉) = 30 𝑊
Solar panel power requirements were then calculated using the following equations.
𝑃𝑢𝑚𝑝 𝐷𝑎𝑖𝑙𝑦 𝑟𝑢𝑛 𝑡𝑖𝑚𝑒 (𝑡𝑜𝑛 ): 𝑢𝑛𝑘𝑛𝑜𝑤𝑛
𝑀𝑖𝑛𝑖𝑚𝑢𝑚 𝑠𝑢𝑛𝑙𝑖𝑔ℎ𝑡 (𝑡𝑠𝑢𝑛 ): 8 ℎ𝑜𝑢𝑟𝑠
𝑇𝑖𝑚𝑒 𝑤𝑖𝑡ℎ𝑜𝑢𝑡 𝑠𝑢𝑛 (𝑜𝑛 𝑏𝑎𝑡𝑡𝑒𝑟𝑖𝑒𝑠): 3 𝑑𝑎𝑦𝑠
𝐸𝑛𝑒𝑟𝑔𝑦 𝑝𝑟𝑜𝑑𝑢𝑐𝑒𝑑 = 𝑃𝑝𝑎𝑛𝑒𝑙 𝑡𝑠𝑢𝑛 (2 𝑝𝑎𝑛𝑒𝑙𝑠)
𝐸𝑛𝑒𝑟𝑔𝑦 𝑐𝑜𝑛𝑠𝑢𝑚𝑒𝑑 = 𝑃𝑝𝑢𝑚𝑝 𝑡𝑜𝑛
𝐸𝑏𝑎𝑡𝑡𝑒𝑟𝑦 = 3𝐸𝑐𝑜𝑛𝑠𝑢𝑚𝑒𝑑 𝑑𝑎𝑖𝑙𝑦
𝐸𝑛𝑒𝑟𝑔𝑦 𝑝𝑟𝑜𝑑𝑢𝑐𝑒𝑑/𝑑𝑎𝑦 = (2 𝑝𝑎𝑛𝑒𝑙𝑠)(𝑃𝑝𝑎𝑛𝑒𝑙 )(𝑡𝑠𝑢𝑛 )
𝐸𝑛𝑒𝑟𝑔𝑦 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 = 3𝑃𝑝𝑢𝑚𝑝 𝑡𝑜𝑛
33
720 𝑊⁄𝑑𝑎𝑦 = 3𝑃𝑝𝑢𝑚𝑝 𝑡𝑜𝑛
𝐷𝑎𝑖𝑙𝑦 𝑟𝑢𝑛 𝑡𝑖𝑚𝑒 (𝑡𝑜𝑛 ): 12 ℎ𝑜𝑢𝑟𝑠
Running 50% duty cycle will average less than 0.25A of drawn current. See Table 2 for
calculation details. Based on receiving 8 hours per day of sunlight, a total of 90 Watts is
required from our solar panels.
Since the pump runs at 620 gallons/hour at 50% duty cycle, it will pump 310
gallons/hour. Based on the assumption that half of our volume in our grow beds is composed of
gravel, the total water in our system is reduced to 254 gallons. Therefore, we will pump the
adequate amount of water per hour.
Appendix B: Materials List
Materials To Buy in Honduras
Price
Plywood:
@ ½” thickness
4 x 8 ft. sheets (need 4 of them)
($12-25 per sheet)
*Not sure about thickness, depends on
what we can find in Honduras
2x4 Lumber:
$20-30
Need approximately 50~60 ft. of wood
Gravel
**Free, gathered from river
in Honduras
Equipment Purchased in the U.S. to bring
Teflon tape
3/4" male PVC adapter
3/4" female PVC adapter
2" PVC cap
2"x5' sch40 PVC
4"x5' sch40 PVC
sales tax
34
Cost
$1.07
$0.56
$0.46
$1.56
$4.58
$7.67
$1.07
Vendor
Lowes
Lowes
Lowes
Lowes
Lowes
Lowes
Lowes
2x
2x
2x
O-ring
sales tax
10 ft 3/4" ID vinyl tube
3/4" male PVC adapter
3/4" plastic hose barbb/male ad.
3/4" brass gate valve
sales tax
3/4"x5' sch40 PVC
$0.39
$0.03
$17.90
$1.18
$2.49
$30.00
$3.48
$1.41
$7.44
$0.56
$0.13
$139.99
$9.45
$25.99
$31.99
$3.91
$120.48
$104.99
-$50.82
$6.56
$60.57
$46.34
$90.85
$3.70
$6.40
$14.84
$25.00
-$39.99
$657.72
Timer
3/4" female PVC adapter
sales tax
45W solar power kit
sales tax
200W power inverter
Submersible fountain pump
sales tax
Pond Liner
Decking Screws
Decking Screws
Staples
AWG 10 wire
Wood
Paint, sealant, brushes
Silicone
Hardware and electrical
Hardware, electric cable, tarp
Stone
Submersible pump return
Total
Ace Hardware
Ace Hardware
Ace Hardware
Ace Hardware
Ace Hardware
Ace Hardware
Ace Hardware
Lowes
Menard’s
Lowes
Lowes
Harbor Freight Tools
Harbor Freight Tools
Harbor Freight Tools
Harbor Freight Tools
Harbor Freight Tools
Lowe's
Lowe's
Lowe's
Lowe's
Promaco
Promaco
HERC
HERC
Promaco
WGM
Northern Tool and Equipment
Appendix C: Equipment Specifications
Solar panels
We bought the exact same solar panel kit from Harbor Freight Tools that is already down
in Honduras from the Aquaponics project in 2011. Acquiring another panel will allow us to
double the power of the system. The 45 Watt kit includes a charge controller, a battery clamp,
cable and a multi Adapter.
35
The following specifications were provided from Harbor Freight’s website:
http://www.harborfreight.com/45-watt-solar-panel-kit-90599.html
Name
Solar Panel Kit, 45 Watt
SKU
68751
Brand
THUNDERBOLT MAGNUM SOLAR
Application
TVs, Lights, Computers, And Recharging 12v
Batteries
Number of Panels
3
Wattage (watts)
45
Product Height
36-21/50 in.
Product Length
12-21/50 in.
Product Width
3/4 in.
Accessories Included
Mounting hardware, 12v light kit, battery
terminal clamps and universal DC power
adapter
Warranty
90 Day
36
Battery
The battery needed for the system is a Deep-Cycle battery. These batteries are ideal for solar
powered systems as these batteries are “designed to be discharged down as much as 80% time
after time, and have much thicker plates.” The battery needed for this system should be a 12 V
battery. Ideally, an unsealed battery, as sealed batteries are sensitive to overcharging, which may
further shorten their useful lifespan. The battery is rated for 105 Amp Hours. The requirement of
our system is only 18 Amp Hours.
Timer
We bought a 24 hour timer to run the pump in 15 minute increments. The description on
the website of the timer is as follows. "WOODS" INDOOR 24 HOUR NIGHTLIGHT *LED
guide light *Timer features nightlight *24 hour cycle - same on/off settings each day *Multiple
on/off settings (maximum 48 per day) *2-C never lose pins *White plate *Rating:
125V/15A/1875W *2 wire non grounded outlet”
37
http://www.hardwareonlinestore.com/index.php?option=com_virtuemart&view=productdetails&
virtuemart_product_id=26947&virtuemart_category_id=1061&Itemid=1&gclid=CLz2zdS1m7Y
CFah9OgodIF0A2A
Pump
The description of the pump we bought from harbor freight is provided below for the 620
GPH pump.
http://www.harborfreight.com/620-gph-submersible-fountain-pump-68393.html
“This versatile fountain pump can shoot a fountain of water skyward or create the look of a
natural spring, giving your pond a little extra character. The ceramic shaft works in fresh and salt
water alike and, in addition to ponds, the pump is also well-suited for large aquariums. Features
include an inline flow control valve, a removable filter for easy cleaning and a removable stand
with suction cup feet.

Ceramic shaft permits use in both fresh and salt water

Inline flow control valve

Removable filter for easy cleaning

Removable stand with suction cup feet

Fountain pump includes two adapters: sprinkler head and waterfall head
38
Appendex D: Maintenance Instructions left in Honduras
Aquaponics Maintenance instructions
May 2013
The Ohio State University
Fish
1. Feed fish every day
2. Keep fish shaded with tarp during the day but keep tarp high enough to allow for air flow
3. Tank is designed for up to 20 full sized fish. Do not overfill.
Plants
1. See plant diagram attached for placement of herbs and vegetables
2. Plant more vegetables as you see fit
39
Water Filtration
1.
2.
3.
4.
5.
Every month: remove the grated cover from the pump and wash out the filter mesh.
With the timer set 50% duty cycle, it should always run 15 minutes on, 15 minutes off.
Every 2-3 days: run the hose to the fish pond if the water is beginning to run low.
Every 2-3 days (or as needed): clean the solids off the top of the fish tank
Every 2 weeks: Test the fish pond water using the testing strips for Nitrite/Nitrate,
Ammonia, pH, and Oxygen levels. Follow the instructions on the testing kit. You will
need the multipurpose strip as well as the Oxygen testing kit.
Treatment



If Nitrites/Nitrates/Ammonia are too high, disconnect the timer and run the pump
for a while to filter the water through. Also, you can flush the system with new
water. If problem continues, consider removing some fish.
If Oxygen levels are too high, increase air circulation by raising tarp.
If pH is off, flush the system more, or consider buying a neutralizing fish water
solution if problem persists.
Electronic Maintenance
1. If for some reason, the solar powered battery stops working, disconnect the pump and
timer and plug them into the grid power using the extension cord with the timer.
2. Keep all electronics rain guarded with the blue cover
Trouble shooting the panels


Ensure that both panel charge controllers located within the wooden box are on and
read a voltage when you push in the black button next to the display screen. The
battery is a 12 V deep cell battery and should function down to about 10 Volts. If the
battery runs too low, switch the pump on to the grid to allow the solar panels to
charge the battery.
See attached diagram for electronic wiring diagram.
40
Electronic wiring diagram
41
Appendix E: References
"Backyard Aquaponics Bringing Food Production Home." Backyard Aquaponics. N.p., 2012.
Web. 18 Apr. 2013. <http://www.backyardaquaponics.com/guide-to-aquaponics/what-isaquaponics/>.
"Company Green Mission Report Now Posted Online - Whole Foods Market
Newsroom." Company Green Mission Report Now Posted Online. Whole Foods Market I.P.,
26 Apr. 2012. Web. 17 Apr. 2013. <http://media.wholefoodsmarket.com/news/companygreen-mission-report-now-posted-online>.
Fox, Bradley. "Construction of Automatic Bell Siphons for Backyard Aquaponic
Systems." College of Tropical Agriculture and Human Resources. University of Hawaii, June
2010. Web. 12 Apr. 2013.
Godelnik, Raz. "Why Whole Foods Is Not a Sustainable Business." Triple Pundit RSS. Triple
Pundit, 9 Mar. 2012. Web. 17 Apr. 2013. <http://www.triplepundit.com/2012/03/foodssuccessful-company-example-business-case-sustainability/>.
Kurtzleben, Danielle. "Walmart Struggles to Overcome Environmental Criticism." US News.
U.S.News & World Report, 20 Apr. 2012. Web. 17 Apr. 2013.
<http://www.usnews.com/news/articles/2012/04/20/walmart-struggles-to-overcomeenvironmental-criticism>.
Nelson, Rebecca L. "Aquaponics Food Production." Tallahassee Sustainability Group.
Tangient LLC, 2013. Web. 23 May 2013. <http://tallahassee-sustainabilitygroup.wikispaces.com/Aquaponic Food Production>.
Newsweek. "Green Rankings 2012: U.S. Companies." The Daily Beast. Newsweek/Daily
Beast, 22 Oct. 2012. Web. 17 Apr. 2013.
<http://www.thedailybeast.com/newsweek/2012/10/22/newsweek-green-rankings2012-u-s-500-list.html>.
Paumgarten, Nick. "Food Fighter." The New Yorker. Conde Nast, 4 Jan. 2010. Web. 17 Apr.
2013. <http://www.newyorker.com/reporting/2010/01/04/100104fa_fact_paumgarten>.
"Practical Aquaponics." Japan Aquaponics. N.p., n.d. Web. 18 Apr. 2013.
<http://www.japan-aquaponics.com/>.
Rakocy, James. "Ten Guidelines for Aquaponic Systems." Aquaponics Journal. Nelson and
Pade, Inc, 1997. Web. 18 Apr. 2013.
<http://phoenixpermaculture.ning.com/group/aquaponics>.
Richardson, Jill. "Is Whole Foods Sustainable or Just a High-Priced Hoax?" Alternet. Ig
Publishing, 17 Aug. 2009. Web. 17 Apr. 2013.
42
<http://www.alternet.org/story/141973/is_whole_foods_sustainable_or_just_a_highpriced_hoax_i_took_a_job_there_to_find_out?page=0,4>.
"Standards For Suppliers Manual." Walmart Stores, Inc., Jan. 2012. Web.
<http://az204679.vo.msecnd.net/media/documents/standards-for-suppliersmanual_129833075555266802.pdf>.
"Sustainability and Our Future." Whole Foods Market. Whole Foods Market I.P., 2012. Web.
15 Apr. 2013. <http://www.wholefoodsmarket.com/mission-values/corevalues/sustainability-and-our-future>.
43
Appendix F: Team Agreement
Project: Aquaponics
Date: Spring & May Semester 2013
Role
Team members
Email
Phone
Team member
Chelsea Dailey
dailey.156@osu.edu
740-815-1143
Treasurer
Matt McCracken
mccracken.89@osu.edu
419-346-5019
Communicator
Justin Letts
letts.5@osu.edu
330-321-7345
Documenter
Nikki Pangilinan
pangilinan.2@osu.edu
703-927-1457
Leader
Emmy Schroder
Scheduler
Jared Stayer
eschroder.15@gmail.com 513-602-8812
stayer.3@osu.edu
330-461-2730
Introduction
The purpose of this team working agreement is to outline standardized expectations for the
Aquaponics project concerning, but not limited to, the working relations and group structure
among team members participating in the service learning trip to Choluteca, Honduras. The
contents herein addressed are:
1. Communication
2. Decision making
3. Responsibility
4. Participation
5. Leadership
6. Consequences
Communication
44
Communication between team members is a crucial aspect of the aquaponics project in order to
achieve success. Main methods of communication shall be through e-mail, phone conversations,
and team meetings held twice a week during our specified class time. It is recommended that
members check their email daily and reply when requested or necessary. If a member cannot
attend class, it is their responsibility to contact one member of the group in order to catch up on
the missed information. To achieve maximum potential of the group, each member should be
clear with their ideas, as well as practice active, effective listening skills. Communication with
the Overholts will also be very important as they are our customer and we must heed their input
as much as possible.
Decision Making
All ideas and decisions concerning the project will be kept open for discussion until a final
consensus decision is made by the group. After that decision is made, it can be revised if all
members of the group decide it is appropriate. When a decision cannot be made, a vote will be
taken. In the event of a tie, a coin toss will decide the outcome of the decision. If a member is
absent from a meeting where a vote takes place, he/she forfeits the vote. If there is still conflict in
decision making, Miriam and/or Roger will be consulted for ideas, but the decision will come
down to the group voting as a whole.
Responsibility
Members of the team are expected to complete any and all tasks assigned to them by the due
date. If unforeseen obstacles prevent task completion, this will be handled accordingly through
team communication. Difficult or unclear responsibilities must be voiced to other team members
swiftly so that they can be clarified or redefined. Each member is accountable for their assigned
goals and if not completed, consequences will occur.
Leadership
Leadership is informal with a discussion-based system used for decision-making. Our team
leaders along with all participants will designate a primary meeting facilitator for important
discussions prior to each meeting. This facilitator will be responsible for compiling an agenda
and directing the smooth flow of the meeting. Natural leadership will evolve over time, and our
working agreement shall be edited if logistical changes are needed.
Group Progress
The group will create a Gantt chart to keep track of all deadlines for the project as well as the
intermediate tasks to be completed. This chart will be referred to at each meeting in order to
assign necessary work and to complete the project on time.
45
Consequences
Consequences will be based on judgement by the team. Should a team member not complete
their given assignments, the group will decide necessary measures to ensure project completion
and decide the status of the member at fault. If a team member believes ahead of time that they
will not be able to complete an assignment on time, they should let the group know at least a day
in advance.
Status may come into question when:
1. Member misses meetings without communication 24 hours prior or a legitimate conflict.
2. Failure to abide by the rules presented in this working agreement.
3. Low commitment and substandard work presented in assigned tasks.
Signature
Chelsea Dailey
Date
Justin Letts
Date
Jared Stayer
Date
Matt McCracken
Date
Nikki Pangilinan
Date
Emmy Schroder
Date
46