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Water and Agriculture Team
March 2010 Montaña de Luz
Eng 692
Post-Trip Documentation
April 21, 2010
Written By:
Peter Dobler
Chris Ratcliff
Francis Krivanka
Kevin Kuhn
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Table of Contents
I. Introduction/Goals ……………………………………………… ….Page 3
II. Plans for Implementation……………………………………………Page 5
III. Schedule while in Honduras……………………………………….Page 7
IV. Expenses…………………………………………………………...Page 9
V. Objectives Achieved……………………………………………….Page 10
VI. Future Recommendations…………………………………………...Page 22
VII. Packing List………………………………………………………...Page 31
VIII. Useful Spanish Words…………………………………………….Page 32
IX. Team Agreement…………………………………………………Page 33
X. References………………………………………………………… Page 34
Appendices…………………………………………………………….Page 35
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I. Introduction/Goals
Previous years have made a lot of progress in the area of water filtration at an orphanage
for kids with HIV/AIDS in Montaña de Luz, Honduras. The water system has been tested and
shown to work effectively to kill off most of the bacteria and viruses present in the water. The
presence of arsenic in the water has proved to be an issue and has been thoroughly tested and a
filtration system installed to lower the level arsenic to the WHO standard. A problem with
changing directors at the orphanage has, however, lead to the loss of knowledge of the use and
exchange of filters provided to remove the arsenic. As a group, we plan on educating the existing
directors at the orphanage in how and why it is important to switch out the filters regularly. That
way they can keep up the filtration of the water to keep the children as healthy as possible.
In the past, the orphanage had tried to set up a Tilapia pond in order to get a secondary
source of protein for the children. Problems arose from the design of the pond and the lack of
information needed to sustain the pond. Tilapia is a very resilient species of fish and they tend to
strive in all kinds of terrain. They are full of protein and tend to be a lighter flavor fish, making
them very popular. As of now, the orphanage does not plan on reestablishing a new pond until a
concrete plan of how to run it is made. During our stay at the orphanage we plan to assess the
area in order to create a more definite plan in building the tilapia pond in the future.
The orphanage has an existing garden but it seems to have problems throughout the year.
The extreme heat of the dry season and the pounding rain of the wet season take a toll on the
plants. Also the terraced garden has problems with the rocky terrain and the plants not being able
to get enough nutrients. A compost bin was constructed many years ago to help with the garden
but has not been used due to lack of knowledge of what is supposed to go into it. The design and
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use of the compost bin will be written in an easier and more descriptive way to make it easy for
the orphanage to use the benefits of composting. A garden tarp will be installed over the plot in
order to reduce the amount of sunlight that is allowed to reach the plants and will also reduce the
pressure of the rainfall on the plants.
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II. Plans for Implementation
A. Water Quality
We plan to install new filters in the filtration systems that were brought to MDL in previous
years. Vicki has already offered to order the filters and bring them down to MDL when she goes
a few days before us. The installation of the filters will be done with the aid of instruction
manuals found for the products online. Once installed and functioning, we will make an
assessment of the filter utility with the goal of making them as functional as possible. We know
that the flow rates for these filters can be very slow and that this represents a possible problem
for sustainability. We will try to work out a way to make the filling of drinking water containers
as easy as possible. We will try to get as much input from the staff who will actually be using
these filters as possible. One idea we have is to buy a large reservoir tank that can remain full
and be used to fill drinking water jugs at a faster rate. Another idea is to buy extra drinking
water containers and somehow automate the filling so that they can be filled easily and are
available to replace when needed. Either way, this will probably require a trip to Tegucigalpa to
purchase water containers from a hardware store. Exact plans for this are still being discussed
and may not be finalized until speaking with the MDL staff.
It is unclear to what extent we will be able to test the water at MDL. An arsenic test kit
was brought to MDL by a previous group, but it seems to have been lost when the roof of the
building it was in blew off in a storm. We will measure the chlorine in the water to ensure that
the chlorinator is working correctly.
B. Tilapia Pond
The Tilapia pond assessment will begin with an assessment on the old pond to determine the
feasibility of incorporation with future ponds. We would like to include the old pond in the
design for a new pond to save money and effort if possible. We would also like to learn anything
we can from the old pond. For example how they constructed the pond and how they managed
water leakage. The assessment will also include soil testing, water testing, and surveying of the
property.
We would like to test the soil for water retention capability. We are not very optimistic in
this because we already know the soil to be rocky. This will be done by simply digging a hole
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and filling it with water. We will test a control by digging a similar sized hole and placing a
leak-free bucket inside. We expect to lose water from the pond from evaporation and this will
allow a rough measure of those losses.
The only water test we are concerned with is pH because in certain pH ranges tilapia cannot
live. Other water quality tests are not necessary as extensive water quality data is already
available from work done by previous groups. pH tests can be done simply with litmus paper.
We will need to make sure to test the ground water that has not been chlorinated as the tilapia
pond must not be filled with chlorinated water.
Surveying the property will be necessary for us to make our recommendations for pond
design. We will take notes, measurements and photos of areas on the property where the pond
could possibly go. We will take account of the following design considerations: slope of the
land, the composition of the soil, and the proximity of the location to the chicken coup and the
garden.
The assessment document will be written after we return from MDL and will be a
compilation of all the research we did prior to the trip and all that we learned from being at
MDL. We will translate, as much as possible, the document to Spanish and it will be sent to
Vicki. We will also try to explain, as much as we can, what we have learned to the staff at MDL
who are interested. From this we may gain a lot of insight into different constraints or ideas that
we may not have thought of.
C. Garden
Instillation of a roof for the garden at MDL will take some assessment to determine the
design for the structure. From the few pictures we have seen, it appears that some structure is
already in place, but might not be ideal. The amount of roofing material we will purchase will
depend on what we can afford . We will also purchase some equipment for the support structure
of the roof. The price is listed in the expenses section of this document. Again, the final design
will depend on what we find when we arrive, but we expect to either use extra material available
at MDL to complete the project or take a trip to the hardware store in Tegucigalpa.
We will also write an instructional document on composting before the trip in English and
Spanish to bring to MDL. We will explain the concept of composting to those staff that might be
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involved and try to answer any questions they may have about the process of composting or why
it’s necessary.
III. Schedule
Saturday





Arrive at Tegucigalpa by noon
Purchase materials
Preliminary investigation of MdL grounds
Discuss with staff about availability of local experts (Tilapia Pond, Garden, Water
System). Adjust schedule accordingly.
Evaluate progress, plan for Monday
Sunday

Excursion day
Monday

Water Day
o Preliminary tests – test water, check functionality of all systems
o Install filter system and cartridges
o Test water again once system is installed
o Develop system for water storage using large container
o Travel to store for additional materials if necessary
o Evaluate progress, plan for the following day
Tuesday

Garden Day
o Examine MdL grounds, take measurements of garden areas
o Discuss roof idea (shade netting) with staff
o Install shade netting
o Evaluate progress, plan for the following day
Wednesday

Tilapia Pond Day
o Examine existing pond
o Discuss options with staff, local experts
o Research available local resources
o Evaluate progress, plan for the following day
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Thursday

Garden Day
o Develop prototype tower garden if desired by staff
o Evaluate progress, plan for the following day
Friday

Free Day
o Available time to finish any projects that may have been postponed or were left
unfinished
o Also free to help other teams or MdL staff with remaining tasks
Saturday

Departure
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IV. Expenses
Cost of Materials



Shade Netting for garden
o Greenhousemegastore.com
 40% Black Knitted Shade Cloth – 26’x 72’
 600’ of 1/8’’ black rope
 rope/wire to connect netting
Water testing kits
Large container for water
Maximum Predicted Total Cost
$246.00
$39.00
$30.00
$50.00
$10.00-$20.00
$385.00
Water Filtration System
Living Water Unit- $356.15 (already at MdL)
LW10KCER Cartridge
$75.65 6 mo.
LW10CBR/ST.1 Ster-O-Tap Combi Ultrafiltration Cartridge $67.15 4 mo.
LW10FRC
$42.08 4 mo.
cost per year:
Costs for water filtration system covered by MdL.
$478.99
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V. Objectives Achieved
One of the high priority projects for the team was making the water filtration system in
the kitchen of MdL functional and ensuring that the project was sustained in the future. This
system had previously been researched and installed by several years of previous groups, but was
currently disconnected due to a low flow rate out of the system caused by the lack of
replacement filter cartridges. The system, consisting of three cartridges connected in order and
with an output faucet over the sink, is shown below:
Figure 1: MdL Water Filtration System
Due to the high cost of the current system, the team researched alternative options for
arsenic removal, such as biosand filters, but determined that the current system would be the best
choice for MdL. The team, in conjunction with Vicki Rush, the executive director, determined
that the filtration system in the MdL kitchen was a higher priority than the system in the
director’s house, so two replacement sets of cartridges were ordered for this system. Also, when
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the filters were ordered, a new version of the filters was available, so the documentation was
updated with that in mind.
Since the main problem with the previous projects had been the lack of effective
communication with the MdL staff, this year’s project was largely focused around making sure
that MdL was on the same page and understood what needed to be done to keep the system
functioning adequately. Vicki also assured us that the current staff would sustain our efforts,
since communications broke down when the old staff left and transitioned to the new staff. To
fix this problem, we first made sure that Vicki knew exactly what was going on, then had several
meetings with the staff at the beginning and end of the week to communicate what was being
done. The filters were changed and replaced with the updated models, and the instructions that
came with the filters were put on the wall in the kitchen in the correct order behind the filtration
system so that the staff would easily know without needing to look at documentation where and
how to place the filters. Also, the team documentation that explained the need for the filters, the
appearance, function, and cost of each filter, and ordering instructions for more filters was placed
on the wall in both English and Spanish. These two components are both shown below, and are
designed to make sure that the staff has as much information immediately available to them as
possible so that there is no way they can be unaware of what needs to be done. All this has also
been waterproofed so that it will last.
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Figure 2: Filter Instructions
Figure 3: Filtration Information
After the filters were installed, the water was tested with an arsenic kit donated from
Hach to ensure that the filtration process was still effective with the new filters. The results were
extremely promising, with the water before filtration having an arsenic level of about 30-40 ppb
and after filtration with an arsenic level of about 5 ppb, well below the World Health
Organization standard of 10 ppb. These results are shown below
Figure 4: Non-filtered Water Arsenic Test
Figure 5: Filtered Water Arsenic Test
Chlorine levels were also tested with the photometer obtained from Dr. Walker to ensure
that there were no unanticipated problems with the chlorination system, but no problems were
observed with the chlorine concentration.
Overall, the water project was a success, and will continue to provide clean drinking
water to the children of MdL with proper limited maintenance for years to come.
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Compost
In order to recycle some of the kitchen waste produced at MdL and use it to benefit the
agriculture of the grounds, research was done prior to the trip on the subject of composting. It
was found that on the grounds of MdL there was an area behind the chicken coop where all of
the waste was stored in rubber bins. This area was not very well kempt – there was waste
overflowing onto the ground. There were also a lot of plastic wrappers and other non-organic
waste found in the bins and surrounding area.
It was decided that more bins should be used for storage of this waste in order to keep the
area cleaner. Additionally, instructions for composting would be shared with the staff at MdL –
more specifically, instructions for what types of materials should and should not be composted.
Dry leaves were collected around the grounds in order to establish a good balance of wet
and dry waste for proper composting. The bins which were already full were to be emptied and
refilled with a layered mix of wet and dry waste. Before this could be completed, however, it was
discovered that MdL in fact had a biodigester installed on the grounds. An example of the type of
biodigester which MdL has installed is found below.
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A biodigester is essentially a large reservoir which allows for the biological breakdown
of organic matter. The organic matter is broken down into two different outputs – biogas and
nutrient rich liquid fertilizer. The top of the reservoir holds the biogas which can be tapped into
and used as cheap fuel. The fertilizer comes out of the side of the biodigester opposite to where
the organic matter is input. Biodigester information is posted on the wiki.
Currently at MdL there is a gas line which travels from the reservoir of the biodigester to
the butchering station, but the gas is not currently being utilized. Members of the MdL staff
wanted to bring back the person who installed the biodigester in order to complete the
installation process and make full use of it, but this had not been possible thus far. Below are
some pictures taken at MdL which depict the various visible parts of the biodigester.
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Waste Bins, Biodigester Input, Biogas Reservoir Tap
Biogas Reservoir Tap, Gas Meters
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Biodigester Output Container
Biodigester Output Container
Garden
Through discussions with Vicki, it was discovered that due to the extreme heat of the sun
and the extreme force of the rainfall, the plants in the gardens at MdL struggled and required
protection from the elements in order to survive. The staff at MdL had already begun to build a
roof for the gardens but the project had not been completed. The completed portion included 18
vertical metal poles installed into poured concrete foundations. The poles were in 3 rows with 6
poles per row, and each pole in the middle row was taller than the poles on either side of it.
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There were 6 bent, V-shaped poles that were not yet attached and were to be welded to the
vertical poles to create the basic structure for the roof. Then a material was going to cover the
entire structure, more than likely something similar to the plastic tarp-like material that covered
many of the greenhouses seen in rural Honduras. Instead of completing the welded structure of
the roof according to this plan, however, a different plan was put into place to protect the
gardens.
Holes were drilled at the tops of each of the vertical metal poles. The holes not only
allowed for the poles to be anchored to the walls of the surrounding buildings, but also allowed
for steel cable to be run along each row of poles. The steel cable was purchased from the
hardware store in Tegucigalpa. Shade netting designed specifically for garden use had been
purchased online prior to the trip and was brought down with the group. The netting was
purchased from greenhousemegastore.com and the order amounted to $360.00, including the
bungee cords and plastic ties used for attaching the shade netting. The netting had metal
grommets which were spaced approximately every two feet apart along the edges of the netting.
Plastic ties were then used to connect the shade netting to the steel cables (only a few bungie
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cords were used at the corners). The finished shade netting roof covered a majority of the garden.
One worry which arose after the roof was finished was that since the netting was stretched over
the tops of the poles in the middle row, the netting might tear over time. To prevent excessive
wear on the netting, pieces of plastic weed tarp were placed on the tops of these poles between
the poles and the netting. A diagram of the garden area is given in Appendix C.
The surface temperature of the ground under the shaded area was in fact measured to be
20 degrees (Fahrenheit) cooler than that of the unshaded ground, and this measurement was not
even taken at the hottest time of the day.
Finished Shade Netting Roof
Shaded vs. Unshaded areas of garden
Tilapia Pond
Most of the tilapia pond material can be found under the recommendations section since
this group’s tilapia pond project was mainly assessment and nothing concrete was done while at
MdL. However, much was learned while in Honduras about the potential and means of starting a
tilapia operation. The main objectives achieved were analysis of the current pond, analysis of
location and possibilities for a future, better pond, a water evaporation experiment to help
determine cost, and a lot of information learned from discussion with knowledgeable people
about tilapia, namely Saul, the maintenance guy who knows a lot about tilapia, Claudio Castillo,
an agricultural engineer in charge of the extensive tilapia operation at the University of
Zamorano, and Larry Overholt, a mission worker from Choluteca who specializes in aquaponics
systems with tilapia. Following is some of the information determined from on-site analysis as
well as a brief background.
Tilapia pond background
A tilapia pond is a great way to make use of otherwise poor agricultural land. Tilapia would be a
good source of nutrition for the children and staff of MDL as well as the surrounding
communities and a good source of income for MDL.
Some potential problems for a successful tilapia culture at MDL include:

cost of implementation (construction, feeding, etc.)

overpopulation in the ponds
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
sufficient oxygen for the fish in the ponds

water loss in the pond (especially during the hot, dry season)
In the following section, these issues will be addressed with recommendations for operating
a tilapia pond at MDL. The fundamental concern of MdL staff was to determine if an
investment of resources in tilapia farming was a wise business decision.
Old Pond
The existing tilapia pond at Montaña de Luz has a few major issues. According to conversations
with Saul, the existing pond did work successfully; it was able to hold 7 tilapia/m2 at a time. The
pond was active for 6 months; in that time they were able to grow about 300 fish. Tilapia
fingerlings were bought from an outside source. To keep breeding down, about 96% of the fish
were sterilized, giving a low production rate, if any. The tilapia pond was a success in that they
were able to produce a stock of fish for an extended amount of time. However, because tilapia
are harvested at an age of 6 months, MDL would only harvest 600 fish a year at best. During a
change of staff and director, the pond was determined to be too costly for the number of fish
produced and the project was called to a halt.
The design of the pond is the major factor in the high cost of upkeep relative to
production. The pond appears to have been made aesthetically pleasing and not necessarily
designed to meet criteria. The surface area of a tilapia pond is the factor that determines the
possible number of fish. A pond should be about 1 meter deep. The old pond is deeper than is
needed for tilapia to survive. The greater depth actually increases operating costs. With greater
depth, there is more water that must be aerated to keep the oxygen levels of the pond at the
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correct level. A shallow pond needs less aeration because it has more surface area in contact
with the air. The old pond required the staff to keep pumps running longer to make sure the fish
did not die from a lack of oxygen.
The fundamental problem with the old pond is that it could not hold enough fish to be worth the
cost. A possible use of the old pond is discussed in the reproduction section below.
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VI. Future Recommendations
Despite all that has been done, there still remains much that can be done in the future,
although much of that is with the other projects. In regards to the water component, future teams
should check with Vicki and the resident director to be sure that the filtration system is being
sustained, and that the filters are being replaced and installed correctly by Saul. If not, basically
just troubleshoot the issues. There is also room for improvement in some of the past water
team’s projects, perhaps with the septic system or the gravity feed system. Also, the tilapia pond
will have significant water-related components which will undoubtedly need work when that
gets started. Finally, a more effective line of communication should be established between
MdL and OSU so that redundant or unnecessary projects such as the UV system, which does the
same job as chlorinating the water, do not occur, and so that the OSU group is familiar and up to
date with what MdL is doing so that there are no surprises and that MdL can get the maximum
benefit from what OSU is doing. The UV system, installed by a
different group, is shown below.
Figure 6: UV Filtration System: Why?
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One of the speakers who came to share information with the class prior to the Honduras
trip was Dr. Jay Martin of the department of Food, Agricultural, and Biological Engineering at
The Ohio State University. His presentation included a section regarding two different types of
biodigesters. His knowledge on the subject surely extends much farther than what was shared
that day and would be an incredible resource for research into biodigesters. The biodigester at
MdL is believed to be completely installed – the biogas just needs to be safely tapped into,
tested, measured, and utilized. It could also be a good idea to design a more efficient system for
retrieving the fertilizer from the output container – currently it appears that in order to retrieve
the compost, someone must place a ladder into the container, climb down, and climb back up
while carrying a large container of fertilizer.
The roof which was put up does not cover the entire garden. One future goal is to assess
how effective the roof is for the gardens at MdL and to examine how well the roof is holding up.
Key points to inquire about include how well the plants are doing now that the shade netting is
up, how well the areas of the netting which come into contact with the middle poles are holding
up, and how well the points connecting the netting to the steel cable are holding up (grommets).
Another goal would be to cover the remainder of the garden if the present roof is deemed
effective and if it is so desired by the MdL staff.
Pond Construction
To make tilapia culture successful at MDL, a new pond (or ponds) would have to be constructed.
Our recommendation is to use the land directly in front of the chicken coop. There is a large
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unused area here. Proximity to the garden is a plus as dirty water from a tilapia pond makes
great fertilizer for plants, and proximity to the chicken coop is good because chicken manure is
good for the tilapia pond. A diagram of the current pond is given in Appendix C.
13.6m
8.3m
12.6m
15.6m
One large pond or two smaller ponds could be constructed in the space. The benefit of using two
ponds is that the harvest of the fish could be broken up into two smaller harvests instead of one
large. If, for example, the large pond had a surface area of 120m2 with a depth of 1m, it could
hold 840 (7 fish/m2). Two ponds of 60m2 could hold 420 fish each. The people at MDL would
have to decide whether they would prefer a 840 fish harvest twice a year or a 420 fish harvest 4
times a year.
Tilapia culture around the world uses a few main types of pond: earthen ponds (requiring clay
based soil with good water retention), concrete ponds, liner ponds, or natural ponds. The soil at
MDL is rocky and therefore very porous and would not hold water well enough. Any new pond
at MDL should be made out of concrete. The construction of the pond is more costly and more
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labor intensive with concrete, but is necessary to retain water. Also, a concrete pond should last
for years.
Reproduction
Once tilapias reach sexual maturity at about 6 months old they reproduce every 6 weeks. They
are generally harvested at 6 months as well, so it is possible that reproduction and overpopulation
may not be problems. Overpopulation can deplete oxygen levels in the pond and kill all the fish
in the pond. Reproduction, if controlled, could also represent a means of replenishing the tilapia
stock without spending the money to buy new fish.
From conversations with Saul we learned that tilapia bought for MDL in the past were sterilized.
One option for replenishing MDL’s supply of young fish therefore would be to buy new
sterilized fish for every new cycle.
Probably the simplest solution to controlling Tilapia population is the use of predator fish known
as guapotes. Guapotes will eat young tilapia but leave the mature fish alone. From Zamorano
we learned that 5 Guapotes per 100m2 of pond is enough to control the Tilapia population.
One way to use the old pond would be to use it for mature fish to reproduce. Several weeks
before a harvest, mature fish could be added to the old pond and allowed to reproduce. By the
time the harvest was made, the young fish would be ready to be moved into the large pond. This
could save several weeks of time and harvests could be made more frequently. The techniques
of reproducing tilapia would require further research to determine the potential. The operating
cost of using the old pond would have to be compared to the cost of buying a new stock of fish.
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It would be recommended to maintain the depth of water in the old pond at 1 meter. This could
be done by simply filling the pond in shallow (which would make it hard to access the fish) or by
filling the pond with rocks and setting a new layer of concrete. Reducing the depth of water will
reduce the operating costs.
Feeding
Feeding tilapia is straight forward. From our research we learned that tilapia will eat almost
anything. A main food source for them is naturally growing algae in the pond water. From
discussions with Saul during the trip, algae grew readily in the old pond. Algae grows more
readily if organic matter is added to the pond such as compost, garden scraps, food scraps, or
chicken manure. It is very important, however, to be careful with the amount of algae in the
pond. Too much algae can result in oxygen depletion in the water and overnight fish kills. In
the day, algae photosynthesize providing oxygen to the pond. When the sun sets, algae respire
and use oxygen in the pond. If there is too much algae, the oxygen can be reduced to dangerous
levels for the fish.
Measuring the algae content of the pond is done by simply measuring the visibility of the water.
You should be able to see about 30cm into the water. A ruler with something bright at the end of
it would work. If you can’t see the end when the ruler is submerged 30cm, there is too much
algae. If you can see all the way to the bottom, there is not enough algae.
At Zamorano, the fish are fed with a fish food concentrate in addition to the naturally occurring
algae in the ponds. The concentrate costs 500 lempira for 6 pounds according to ingeniero
Claudio Castillo, and in 6 months 1000 fish will need 1000 pounds of food. The concentrate
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contains protein to ensure a healthy growth rate for the fish. If the fish don’t receive enough
protein, they will grow more slowly and harvest times will be delayed. The concentrate is a safe
and fool proof way of making sure the tilapia get the nutrition they need. As previously
mentioned, however, tilapia will eat a wide range of food. It may be beneficial to try feeding the
tilapia food scraps or chicken scraps (for example, dried chicken blood from butchering). It is
easy enough to determine if they like it. At normal feeding time, throw some in and if they eat it
they like it. Chicken scraps should contain plenty of protein to keep the fish growing at a fast,
healthy rate.
Our recommendation for feeding the tilapia is as follows:
-
Closely monitor the algae growth in the pond ensuring there is a significant amount
available for the fish to eat (this will reduce the amount of store-bought food needed). Using
a ruler with something bright painted on the bottom would be perfect.
-
Feed the fish with the store bought concentrate as a supplement to algae. The concentrate
probably represents the most complete source of nutrition to the tilapia.
-
Experiment with what else the fish like to eat. If they readily eat chicken scraps or other
available sources of protein, the concentrate can be used less and some money could be
saved.
When feeding the fish, toss in a little food. If they are hungry they will soon come to the top to
eat the floating food. Feed until they stop eating.
Pond Oxygen
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Oxygen content in the pond is critical. Fortunately, tilapia can live on only about 7mg of oxygen
per liter of water. This means that under normal day time conditions, the oxygen produced by
algae and the contact between the surface of the pond and the air incorporates provide enough
oxygen for the fish and no special measures need to be taken to add oxygen to the water. At
night time, because the algae in the pond will start using the pond’s oxygen, oxygen will have to
be added to the pond. This would most likely take the form of a pump that simply re-circulates
the water in the pond. The pump will add operating electrical operating costs. One technique to
limit this cost that we learned from Claudio at Zamorano is to monitor the fish for one full night.
When oxygen in the pond gets to dangerously low levels, the fish will rise to the surface and
gulp the air. When this happens, the time should be noted and the pump turned on until sunrise.
This may result in the pump being run on a timer for 3 or 4 hours a night instead of the entire
night. Care should be taken, however, because as the fish grow their oxygen requirements might
increase and the pump may need to be run for longer periods of time at night.
Adding oxygen to the pond continuously could increase the maximum possible population of
tilapia in the pond. With only night time aeration, the population limit is 5 to 10 tilapia per m3
according to Claudio.
Pond Cleaning
Cleanliness of the pond is important. Claudio told us at Zamorano that the requirement for a
clean pond is to replace 10% of the pond’s water in a week. This water would be very high in
nutrients and perfect for watering the MDL garden. Our recommendation would be to build the
pond or ponds with a drainage valve. The valve could lead to PVC piping that could run from
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the chicken coop over to the garden where it could be attached to a hose used to water the
garden. In this way, wasted water would be minimized.
Cost Analysis
This cost analysis is based on one pond of 65m2 that can hold 455 fish each (7 fish/m3). The
analysis is based on the following calculations and is summarized in a table below. It is
important to keep in mind that there will be a large initial cost to build the ponds and fill them
with water. Furthermore, these calculations are based on many assumptions and information
gathered through 2nd language interviews.
•
•
•
Cost of fish:
•
27 Lempira per pound (this was the price at U. of Zamorano)
•
Fish will be about 1 pound each
•
455 lbs * 27L = 12,285L
Cost of stocking fish:
•
85 centimos per fish (this was the price at U. of Zamorano)
•
0.85*455 = 386.7 Lempira to stock the pond
Cost of feeding
•
One 6lb bag of feed concentrate is 500L
•
Estimate 1/2 bag per week  7,500L per 6 months
30
•
Note: It’s difficult to estimate the amount of food that will be needed. This is
Fish Value
Stocking Cost
Electricity Cost
Feeding Cost
Net
24,570
772
850
13,000
+ 9,948
probably the most variable cost. We honestly don’t have a good idea for how
much it will take, but it could become very expensive. The more additional food
sources that can be used (chicken scraps, etc.) the more money can be saved here.
•
Cost of pump electricity
•
A 20 gallon per minute pump is rated at 1.5A 120V = 180W
•
This pump run for, say, 4 hours a day is 0.72 kWH.
•
0.72 kWH at 18 cents per kWH* is about 13 cents to run the pump a day = 23.66
dollars every 6 months. (~425L per pump per 6 months)
*Note: We’re not sure of the price of electricity
Table: Cost Analysis for two 65 m2 ponds (in Lempira)
Pond Experiment
The Pond experiment was a test to find the evaporation rate of water from a pond in the
area during the dry season. This was done by using a concrete duck pond that was 156 cm in
diameter and a depth of 46 cm. The pond was filled to 30 cm and was allowed to sit open to the
elements. Every day at the same time the water level was marked at 4 points around the pond in
31
order to get an average evaporation rate over the whole pond. The data in Appendix A shows the
flux of water from the pond per day, Na[cm3/day]. The data from the first day shows a large flux,
this is due partly from the evaporation of water but is more affected by the diffusion of the water
into the concrete lining. This is shown to be true in the following days as the flux comes near a
constant flux. The diffusion of the water is a slight factor to take into account when constructing
the pond. Water will be diffuse into the concrete at first but will then come to equilibrium
between the water and the concrete, so water loss after that point will be solely from evaporation.
The loss of water from evaporation is very small on a day to day basis, which will not be a
problem to overcome. About 10% of the water of the pond should be replaced each week, so
keeping the water at the correct level should not form a problem. Non-chlorinated water should
be used to fill the tilapia pond.
VII. Packing List
List of Necessary Materials






Tape Measure
Calculator
Journals
Writing Utensils
Garden (Roof) Materials
o Shade netting
o Grommets/shade clips
o Cables, fasteners
Tower Garden Materials
o Base material (burlap or similar material)
o Rope
o Poles
o Soil/gravel
o Garden Materials
32


Tilapia Pond Materials
o Materials for detailed documentation
 Computer/journal
 Camera
 Schematics
Water Quality Materials
o Testing kit (Chlorine)
o Testing kit (Arsenic)
o Containers to bring water back for testing
o Large container for water (10-15 gallons)
VIII. Useful Spanish Words
water…………………………el agua
agriculture……………………la agricultura
project………………………..el proyecto
garden………………………..el jardin
arsenic………………………..el arsenic
chlorine………………………cloro
filter………………………….filtrar
pond…………………………el estanque
roof………………………….el techo
compost……………………..el mantilla
tower………………………..el torre
sustainable…………………..sostenible
assessment…………………..la evaluacion
33
What do you think?................Que te parece?
Do you have any questions?...........Tienes preguntas?
fish…………………………..el pez
size…………………………..tamaño
cement………………………el cemento
dirt/earth…………………..…la tierra
quality………………………..la calidad
feed…………………………..alimentar, dar de comer a
test………………………..…..probar
leave(e.g. documentation, plans,etc)…..dejar
instructions………………..…instrucciones
IX. Team Agreement
34
35
X. References
Emerson, Brock A. The Development of a Project Management Methodology for Peace Corps
Mauritania. Michigan Technological University 2006. Pg. 76-101, 115-127.
El-Sayed, Abdel-Fattah M. Tilapia Culture. CAB International. 2006
"How to Compost." Web. 9 Mar 2010. <http://vegweb.com/composting/how to.shtml>.
Gall, Aimee, Mandy Jensen, Katie Kinstedt, Lisa Reisenauer, and Eric
Reynolds. "Assessment of the Drinking Water System and Water Quality at
Montaña de Luz and Nueva Esparanza, Honduras." (2008): Web. 9 Mar 2010.
<http://ecos.osu.edu/system/files/TeamAguaReport2008.pdf>.
Rush, Vicki. Personal Interview. 24 Feb. 2010.
Water Harvesting and Aquaculture Development Series
http://www.ag.auburn.edu/fish/international/waterharvestingpubs.php, Auburn
University, Swift, D. R. Aquaculture Training Manual, 1993.
Beveridge M., Brendan, M., Tilapias: Biology and Exploitation. 2000.
Overholt, Larry. Personal Interview. 26 Mar. 2010.
Saul Caceres. Personal Interview. 25 Mar. 2010.
Castillo, Claudio. Personal Interview. 24 Mar. 2010
36
Appendix A: Tilapia Calculations
2
4
A    78  1.911  10
ho  30
h1 
H1  mean( h1)  27.305
0
0
26.67
1
26.988
2
28.575
3
26.988
h2 
0
25.718
1
26.035
2
27.305
h3 
Na1 
ho  H1
t
3
 A  2.146  10
dH2  Stdev( h2)  0.704
Na2 
H1  H2
t
26.035
0
 A  821.779
H3  mean( h3)  25.368
0
25.082
1
24.956
2
26.035
3
25.4
h4 
dH1  Stdev( h1)  0.86
H2  mean( h2)  26.273
0
3
t  24
dH3  Stdev( h3)  0.482
Na3 
H2  H3
t
 A  720.637
H4  mean( h4)  24.447
0
0
24.13
1
24.13
2
25.4
3
24.13
dH4  Stdev( h4)  0.635
Na4 
H3  H4
t
 A  733.28
37
Appendix B: Filtration Documentation (posted at MdL)
Instructions for Maintenance of the Filtration System
The filtration system is very important to remove the arsenic from the water, because
arsenic is a dangerous chemical that can cause serious skin problems after years of exposure.
The filtration system is connected to the sink, and contains three cartridges, that need to be
changed every few months. These cartridges need to be in the right order to function properly.
From left to right, the order is the FRC cartridge, then the KCER cartridge, and the CBRST
cartridge on the right. A brief description of these three cartridges can be found below. Also
there is how often you need to change the cartridges: VERY IMPORTANT.
You can order more cartridges by phone (1-800-680-2596), from the internet at
http://www.mrwaterfilter.com/counter-top/mwfct-06.shtml, or directly from the manufacturer on
the internet at http://www.livingwatersway.com. The cartridges are the three on the Mr. Water
page. They are the LW10FRC cartridge, $45.99, the LW10KCER cartridge, $82.69, and the
38
LW10CBR/ST cartridge, $73.39. They need to be sent to the MdL office in the U.S. and the
Filters
Name
FRC
KCER
CBRST
Picture
Function
Removes arsenic
and fluorine
Removes small
particles and the
taste of chlorine
Kills bacteria
Appearance
White
White and thin
White and blue
with meshing
Time before
Replacement
Every 4 months
Every 6 months
Every 4 months
director there can take them by plane to Honduras.
39
Instrucciones para mantener el sistema de filtracion
El sistema de filtracion es muy importante para limpiar el agua porque quita el arsenio
del agua, que es un quimico peligroso que despues de algunos anos puede causar muchos
problemas graves del piel. Este sistema de filtracion consiste en el sistema que se conecta al
agua, y de los tres cartuchos, que necesitan ser recambiados despues de algunos meses. Estos
cartuchos necesitan estar en el orden correcto para funcionar bien. De la izquierda a la derecha,
el orden es el cartucho FRC, el cartucho KCER, y el por la derecha el cartucho CBRST. Una
descripcion breve de estos tres cartuchos esta abajo. Tambien hay cuando se necesita recambiar
los cartuchos: MUY IMPORTANTE.
Se puede pedir otros cartuchos por telefono (1-800-680-2596), del sitio de red
http://www.mrwaterfilter.com/counter-top/mwfct-06.shtml, o directamente del proveedor del
sitio de red http://www.livingwatersway.com. Los que se necesita son los tres que estan en la
primera pagina de red. Son el LW10FRC por $45.99, el LW10KCER por $82.69, y el
40
LW10CBR/ST por $73.39. Se necesita mandarlos a la oficina de Montana de Luz en los
E.E.U.U. y el director alli puede tomarlos por avion a Montana de Luz.
Filtros
Nombre
FRC
KCER
CBRST
Foto
Función
Quita arsénico y
floro
Quita partículas
pequeñas
Mata las bacterias
(metálicos malos) y
el sabor de cloro
Apariencia
Blanco
Delgado y blanco
Blanco y azul con
malla
Vida Útil
Cada 4 meses
Cada 6 meses
Cada 4 meses
41
Appendix C: Measurements (Tilapia Pond and Garden)
42