How to create a micro-climate
in the dessert environment of
Mauritania
Ruud Wichers Schreur
Micha Koster
Tom Spierings
Costijn Blankers
5 HAVO
Hr. Kalhorn
1
Index
 Introduction
Page Numbers:
3
 Finding a Solution
4-5
 Working out and Enhancing the Idea
6-8
 The Desalination System
 Step by Step explanation of the Prototype
 A Simple Graph of the System
 Future Plans
9
10-12
13
14-15
 Summary
16
 Conclusion
17
 Personal Evaluations
18-19
 Annexes
20-24
 Logs
25-36
2
Introduction of our assignment
This is our world school report we made. The main objective of this report was to help the
Mauritanian inhabitants to create a micro-climate in a desert environment. But first let us explain to
you how we got to making this report. When a normal fourth year student start in Holland they will
start to hear information about a report which is specified to your different classes, and it is made in
Dutch. Our report is made with the help of world school and has an actual helpful subject for the
people you are going to help. First let me explain what world school is. World school is an
organization which plans projects for students all over the world. Their goal is to combine meaningful
connections between schools and the real world, high quality education, students as active 'world
citizens' and sustainable development as an important value.With their help we made the choice of
the subject. We eventually choose for, “How to create a micro-climate in the dessert environment of
Mauritania.”. We have chosen this one because it seemed the most interesting, and we were looking
forward to working out the plans and hardware needed for this operation. Mauritania is a country
that borders the countries: Western Sahara, Algeria, Mali and Senegal. A big part of Mauritania is
covered by the Sahara desert so there is very little water. The water percentage is 0.03% which is
very low. The population of Mauritania is three million two hundred and ninety one thousand. The
total area is one million thirty thousand seven hundred kilometers squared. This is huge compared to
the Netherlands with forty one thousand eight hundred forty eight. Mauritania's capital is
Nouakchott and it lies and the western border of the country. The main language is Arabic. We work
for a couple of farmers and have to deliver the plans to build a self-consuming farm so they can
produce their own food or create raw materials which can be sold.Mauritania is a poor country. The
average nominal income per capita is 975 dollars. This is a fraction of what the average nominal
income per capita is in Holland, which is forty six thousand four hundred and eighteen. Most of
Mauritania’s population still depends on agriculture and livestock. This indicates how well the
country is developed. 50% of Mauritania’s exports are made up of iron ore. Mauritania has also been
described as “desperately poor desert nation, which straddles the Arab and African worlds and is
Africa’s newest, if small-scale, oil producer”. When we started this project we contacted our contact
person in Africa, her name was Stephanie Waasdorp. We contacted with her several times. She
works for a company called 2unite.2 unite sees microcredits as a way to fight poverty in Africa. Our
project is a part of 2 unite. 2unite tries to help Africa completely. For this report to be completed we
need to work very hard. We are also planning on giving parts of this subject through to the next
world school participants.
3
Finding a solution
After recievieng our project objective to create a microclimate in Mauritania, we understood
that we had to create firtillized soil in which to grow certain plants, which could be achieved by the
usage of as little money as possible. We quickly started thinking about the most obvious source of
fertilizer, which turned out wasn’t as easy as one might expect. Therefore, our first objective was to
find a great amount of fertilizer in a country with less than 50mm of rain per month for most of the
year. So where in a dry desert could we find a large amount of fertilizer, which could cheaply be
extracted in such a dry country?
With an extremely limited amount of sources, we came to the conclusion that seaweed was
the firtillizer we were going for. Seaweed can be found in the Pacific Ocean which lies less than 3Km
from our microclimate. However, the problem with seaweed is its salt content. It is likely that we
would add sufficient seaweed to seriously upset the balances of salt in the soil, so extracting the salt
from the seaweed was critical. Seaweed can be hosed down before adding to the soil to reduce the
salt content, or left to be desalinated by rainwater. This created yet another problem, for in
Mauritania, it barely rains, and there obviously aren’t any pipelines, so using a hose is also out of the
question.
Our next step was to create fresh water in the desert. So we clearly, decided to go with
desalination by means of reverse osmosis. Coming up with an idea to simplify, and therefore
cheapen the process of desalination was our hardest task so far.
So we decided to use the temperatures to our advantage. Where temperatures can reach up to 40
degrees celcius, and that is without the use of the raging heat of the sun, there was clearly an easy
way to heat up water without the use of any source of energy other that the sun.
We came up with a prototype, which has a black surface for maximum heat obsorption by
the sun, and a simple cooling system that can be used even in the heat. The cooling system needs
nothing other than sand and water to cool down the condenced water. This entire prototype is
extensively explained further on in this report.
4
Source: www.climatetemp.info/mauritania/
This graph shows the differences of ecological factors throughout the year. From this graph
can be concluded that there is hardly any rainfall and the difference between air and sea
temperatures are aproximately 10 degrees centigrade during daytime but a lot more during
the morning, evening and night.
-You can see that the maximum temperatures reach up to 35 degrees celcius, whilst rainfall
between December and May is less than 50mm per month.
-The average sunlight never recedes less than 8 hours per day, so there is always enough sun
for the desalination system.
To sum up, the graph confirms our thoughts on how to extract the salt from the seaweed,
because there is enough heat to desalinate the salt water, which is needed, because there is
only enough rain water to extract the salt from the seaweed in August.
5
Working out and enhancing the idea
We started of looking for a way to fertilize the ground around the resource or plants. Because we
needed to make the ground or soil fertile for it to grow plants. We started of looking for a way on the
internet and came across an article which said that a good solution might be to use seaweed. This is
similar to a method the plant physiologist Huub Lindhort from the University of Leiden recommended
us.
``Many gardeners use seaweed as an organic fertilizer to supplement their plants'
nutritional needs. Trace elements found in seaweed include magnesium, potassium, and nitrogen,
which are beneficial to plants. Because seaweed is a completely natural product, you can use it to
fertilize your soil knowing that you are not adding any toxic chemicals, which may be found in
commercially produced fertilizers. If you are lucky enough to live near the ocean, you can collect your
own fresh seaweed; if not, dry seaweed powder and liquid seaweed fertilizer does the same job. ``
Quoted from http://www.ehow.co.uk/how_7999905_use-seaweed-fertilizer.html
It also included some crucial steps to make it work.

Use a bucket to collect fresh seaweed from the ocean.

Place the seaweed into the colander. Rinse the seaweed repeatedly with the fresh water in
the colander to remove salt and sand.

Apply two handfuls of the clean seaweed fertilizer to the dirt around the tomato plant.

Water the plants soil with the seaweed immediately.

Apply seaweed weekly if possible. If not, one application is helpful. As the seaweed breaks
down, it will turn white or transparent.
The first step was relatively easy because Mauritania is located next to the sea, and there is plenty of
seaweed there of course. To collect the seaweed the inhabitants needed buckets and a rake. When
we contacted the 2unite organization in Africa, they said that they possess such tools. To perform
step 2 the inhabitants of Mauritania needed a colander. A colander is a large bucket with holes in it
to wash the salt out of the seaweed. To do this you need to rinse the seaweed with fresh water. The
problem with this was that they do not have enough fresh water in Mauritania to do this. Fresh
water is scares in the African counties of course. So we needed to create a way to make fresh water
out of salt water. This was our first objective.
6
The first solution we came across was a hot-cold plate convertor based on a peltier unit. This is easily
explained. First of you need to buy 2 peltier units. This is a plate with two sides. One side gives of
heat and one is realy cold. By letting one type of heat energy flow into a heatsink you can create a
extremely hot or a extremely cold side. So this is the system were we came up was.
So, the salt water start of in the right part of box, because the hot part of the hot-cold plate
convertor is on the salt water side of the box, because of this the water evaporates and leaves the
salt behind. The salt water changes into water damp and gasses which flows into the left side of the
box where it condensates and turn in to fresh water.
Only there is one problem with this solution. It requires electricity. To avoid this problem we have
made some calls and came to a Japanese international seller who sells peltier units working on a 12v
power supply. This had another advantage because a regular car has a 12v power supply and it
recharges while the car is driven so there are no other extra costs made. But unfortunately the local
population could not afford a car.
After that we needed to find a system that works and is made up with resources that the inhabitants
of Mauritania have to their disposal
7
Another option was the seaweed squashier this is based on reversed osmose. It is a cylinder with a
small cylinder inside it. Around the small cylinder is a rubber coating. There is a double wire attached
which you can turn around to gain pressure. Once the pressure is high enough the semi permeable
membrane and the salt is extracted.
8
The desalination system
(parts and their function)
Now we reached our final idea. It is based on desalination systems but as you can see in the scheme
it is a very difficult process. It is expensive to procure and maintain. Not even to think of the lack of
intelligence so if anything goes wrong the local population will be unable to fix it and an expert has to
come over which could take some time and in the worst scenario destroy the harvest. To avoid all
these possible problems we decided to make a easy to understand system requires has hardly any
maintenance costs because the local population could use their money for a lot better purposes and
works at least as efficiently. It is based on nothing more as the sun and the only requirements are
that the fresh water reservoir has to stand in the shadow and the system itself gets as much radiation
from the sun as possible.
This graph shows the desalination system that is currently used in more wealthy countries it is far to
difficult to understand for the local population of Mauritania.
Source: http://www.nerc.gov.jo/Photovoltaic/PV%20Image/DesalinationSystem2.gif
9
The step by step explanation of the parts of
the system
10
A: The sun
The people that we work for have only a little bit of money if they even have money so we have to
develop a system that is able to distillate water and hardly requires any costs to maintain it. At first
we need energy; there are two usable forms of energy which are electricity and heat energy. Since
electricity cost’s money and is not in every country as easy to obtain and may require some
knowledge about the electronics which might be difficult for the “lower” educated population we
chose for the only free source of energy which is heat energy.
In Mauritania there are 8 to 10 hours of sunlight a day. And hardly any clouds in the sky that block
the sunlight.
The sun has always been and probably will always be the only free source of energy, It does not
require any costs to set it up or to maintain it. It is available for 99,9% during daylight. And therefore
perfectly suits as a main source for our project
B: The Salt water reservoir
This is a big shallow box. It is around 5-7 cm deep and has a big surface. This is so that the maximum
radiation from the sun gets in touch with the salt water. It is a fact that black things attract more heat
so the box is colored black too.
C: The Salt water
The salt water is taken directly from the sea and is free. It is only a 2 km walk to the sea. The water is
heated up and the only source of energy that is used is sunlight. Once the water is warming up the
H2O molecules start to move faster and they turn from a liquid to a gas (please note that water is not
required to boil to evaporate! How would there ever be any rainfall on the earth? Since there is no
place where water is reaching the temperature of 100 degrees without any other energy than
radiation from the sun put in). Since the salt particles are a solid they will not turn into a gas and the
salt particles are left behind. Since hot air rises the gas flows up. This leads us to the next part: The
pyramid roof
D: The pyramid roof
Since we need to cool down the gas we need to collect the hot air at a central point. The best way to
do this is by letting the hot air flow up along the sides of a pyramid roof. All the hot air will be taken
to the top of the pyramid since there is no other movement than upwards movement. The roof has
to be transparent because we don’t want it to block the sunlight from reaching the salt water
reservoir. The other advantage of a transparent roof is that it will not be affected by the attraction or
reflection of heat. So the warm air that is rising is not yet cooling down and condensation does not
take place.
11
E: Gas Tube
The pyramid roof has to be supported so we chose for a pipe with holes in it. It works exactly the
same as the older model of camping tents. Just one “stick” that holds the roof up. We can also assign
a second function to this pipe by transporting the hot air into the cooling unit. This way we could let
the hot air flow into the pipe and use the real top of the pyramid as an exit of the evaporation cabin.
And we do not have to make a hole on the side close to the top which causes some hot air to be lost.
F: The cooling unit
The inner pipe has the evaporated H2O flowing through. Around the inner pipe is another pipe with
wet sand in it. This causes that the water of the wet sand is evaporating and the strength of the
radiation of the sunlight is lost( which is expressed in heat) the inner pipe will be a cool area then and
lets the hot air cool down and condensate. The water vapor will turn into fresh water and because of
the downwards move of the inner pipe the water will flow down. The advantage of this cooling unit
is that it needs only a few minutes to start up. This is because once cold water is inserted the
temperature of the inner pipe will drop and the evaporation starts to take place because of the quick
difference in temperature
G:The Gutter
The water in the sand that is condensating needs a way out through the gutter to release the energy
that is put in by the radiation which turned in heat. Once the most of the water is evaporated and
the sand in the cooling unit is warmed up and slowly getting dry it can be easily cooled down by
putting new water into the gutter and let it be soaked up by the dry sand so it becomes wet again.
H: The Funnel
A small pipe at the end of the cooling unit with its opening a little bit in the fresh water cabin. This
prevents the wind from interfering with the he droplets of water that are falling so they won’t be
blown away. Because of the shadow of the fresh water cabin not a lot of sunlight can reach the water
anymore which also minimizes the amount of clear water being
I: The fresh Water cabin
A deep and bright colored cabin with a small surface. It is placed in the shadow so not a lot of
sunlight can touch the water. The bright color of the inner side of the barrel, The cooling unit around
it and the fact that it is deep will reduce the amount of fresh water evaporated a lot. This will be big
enough to store water for quite some time to be prepared in cases extreme warmth will occur.
12
A Simple graph of the system
• Free source of energy expressed as heat.
The Sun
Salt water
• Split H2O from NaCl by evaporation.
• Water is heated up and becomes a gass, Hot air rises.
Water Vapour
• Roof in the shape of a pyramid brings the air to a central point.
Pyramid roof
Gas tube
Funnel
• A pipe surrounded by a cooling unit with a downwards movement
converts the water vapour into water droplets again.
• Water droplets drip out of the funel into the fresh water resevoir
13
Future plans
The first product we need is seaweed. We sprinkle the seaweed with fresh water to extract the salt.
This is why we have developed a system that evaporates water from the salt. This is properly
explained in the past paragraphs.
The desalination system we have developed is light, cheap, and effective. It needs no electricity or
fire, only the heat of the sun. This can be very useful for inhabitants of countries with little water
sources. For example, we have made a ready-to-build packet for inhabitants of these countries. The
heat of the sun is absorbed by a black basin where the salt water is put. The heat of the sun
evaporates the water and this travels through a tube which is, on the outside, covered with sand to
create a cool temperature where the water can condense back into fresh water.
Many counties have limited water supply. The cause is mostly because they don't have many fresh
water sources in their country like lakes or rivers. Like Mauritania, it lies in the Sahara desert with
almost no water supply what so ever. To be exact, 0.03% of Mauritania's surface is covered with
water. Whereas Holland's surface is covered with 18.41% water. With this packet we supply the
inhabitants with an alternative water source which they can use for anything they need; growing
crops, fresh water or fertilizing their farm by sprinkling seaweed with fresh water and using it for
compost. This packet is designed for individual use but can also be built in a larger form for supplying
multiple consumers with
• PVC
water.
Buying
materials
• Plastics
This so called 'packet' is
actually the water
Assemble • Manual
desalination system but
all parts • Building materials
into a
split into all the building
package
materials. We have done
this because it is easier to
• By worldwide air services like DHL or FedEx
Ship to
country
ship, and it saves us a lot
of time building every
• The manual is easy to follow and every person will
single system. This system
Package
be able to build their own desalination plant
is very easy to build, it
built
contains everything you
need including a manual,
building materials like bolts, pipes and the two basins. The
manual includes easy to follow steps on how to build the system, how to make it work effectively like
where to place the system and our information in case they need any spare parts. The manual is
written in two languages; the first is English and the second the native language (in Mauritania's case
it is Arabic). This manual will also contain many pictures for people which can't read or write. The
desalination system is built from not only cheap materials like PVC piping and many other plastics.
We chose to build our system with cheap materials because then the package costs a lot less and if
any parts are broken they are easier to replace. You can imagine that a desalination system made
from durable metals can be very expensive, for most third world countries too expensive.
To make everything clear, we have created a list of how our process will be handled.
14
The future of our project:
Our school introduced the Worldschool project this year. Never has a graduate class done a different
project from the rest. We were given the assignment as well as the rest of the IB class. We were
given subjects and we had to chose one. We chose the one about creating a microclimate because
Ruud takes Biology, Chemistry and Geography classes. Micha, Tom and Costijn take Chemistry and
Physics classes. Here we learn how certain aspects of our subject work, like the evaporation of water
from salt water to create fresh freshwater.
As we chose our subject we evaluated it with the group. We started working it out but did not come
further than creating a water desalination plant. As a group we wanted to continue but our teacher
told us to develop our idea and concept further. There still have to be taken many steps until a
microclimate is created. We made the first step, creating a low-cost system that produces fresh
water but other steps like making the ground fertile and maintaining the soil still have to be taken.
This might be a task for future classes. We will give the next class our idea and they can further
develop it because of our lack of time. We will develop our desalination system further until we
reach our goal, selling our product to countries who need fresh water, and let the following group
continue our work.
15
Summary
We started as group on this project to create a microclimate. We started off by brainstorming
about how to create a microclimate. A microclimate is a climate which differs from its
surroundings. An example of this is the city of San Francisco where temperatures at the San
Francisco bay can get up to a maximum of 18 degrees while in the Walnut Creek the
temperatures can rise to 31 degrees Celsius. As a group we were developing ideas about how
to create this microclimate, most idea's led to a problem. One idea we have used in our project
is fertilization of the soil. The problem is, how to we fertilize soil which lies in the Sahara
desert? The solution we found was seaweed. Seaweed acts as a good compost and contains all
the minerals needed for good soil. Seaweed can be found in the Atlantic ocean but contains
one problem; seaweed can only be used as compost when the salt is extracted from it. This
problem got us thinking, but we eventually got to a solution: a desalination system. With fresh
water we could extract the salt from the seaweed. The desalination system needed to be cheap,
reliable and efficient. As a group we made many concepts of how we could make our
desalination system as efficient as possible. The first concept we tried was boiling water with
a fire until it evaporates, then the water would travel to a sheet of plastic where it would cool
down and condensate until it turned back to water. The water would drip of the sheet into a
container. This idea was not efficient enough because the local population needed to supply
wood to make this system work. Later we developed a system that would heat water by the
power of the sun. It worked exactly the same as the system which worked with fire but the salt
water container is black. The container is black because it would absorb more energy of the
sun for heating. We adjusted this system by replacing the sheet of plastic by a tube to make it
more reliable. This concept proved to be efficient and future plans were made. The system
could be packaged and sent to countries which lack freshwater. The manual would explain
how to build this system. The parts are of low-cost plastic so they are easily to replace. So as a
conclusion, our group has developed a system which creates fresh water for the project but
also for the microclimate/agriculture. This will improve the standards of living in Mauritania
and we hope that this system will be demanded. The overall project will be set forth by next
year by the following 5 havo students of our school.
We have a couple of questions for the next students of 5 havo.
* Research which plants can survive under the fertilized soil with seaweed
* Research how you can create freshwater with the evaporated water for the local population
* Research how to make this project profitable for innovations in the future.
16
Conclusion:
We have built a desalination system, designed for the third world countries. With this system we
hope to create a better life for many people in third world countries which need fresh water. Every
year thousands of people die because of a lack of fresh water. We hope to reduce these numbers.
The system will be distributed where needed. It will be sent in a sort of package to prevent high
costs. We hope to have a deal with an global air service like DHL or FedEx so we can distribute our
system globally. The manual will explain everything that you need to know with pictures so people
which don't read or write can still understand.
We hope the next group can pick up our project and develop it further as we hope. We have created
many concepts and idea's they can use so this will be no problem. The following steps still need to be
done:
1. Making the ground fertile using seaweed
2. Maintaining the ground and changing the biodiversity etcetera to create a microclimate.
3. An optional assignment is creating freshwater out of salt water by finding out how to remove
bacteria and maintain the right Ph value. (Just imagine how many people that die because of
starvation or the lack of freshwater would be saved?!)
17
Personal Evaluations
Costijn Blankers
Before we started the project we were looking forward to creating something that could actually
change lives. Thankfully, this opportunity fell into our laps, and gave us the chance to help
unfortunate people. By the time the project started we were all very motivated. During the project
itself we have kept good contact with each other, with our mentor and our contact person in the
African countries. We believe that in the end we have created a well thought out building plan for a
distillation system.
Tom Spierings
In the beginning of the year we were told that the IB students would do a different report than the
other students. We would be working with a company called Worldschool and 2Unite. The
communication went fluently and we quickly got more information about our subject. Creating a
microclimate is not an easy task so we had to think of many possibilities and look up theories of how
a microclimate works. The conclusion was that we had to create fertile soil, to do so we had to use a
fertilizer. The fertilizer we found was seaweed. Seaweed is a good compost and contains all that
nutrients needed for a healthy soil. The problem was that there is too much salt in the seaweed, our
solution is to extract the salt with fresh water. Hereby comes another problem, how do we get fresh
water in the middle of the Sahara desert? We came up with a system which uses salt water. This salt
water is heated by the sun and the fresh water evaporates from the salt. The water cools down as it
rises and drips into a second bucket. This water is not only used for the fertilizer but can also be used
for more purposes like for drinking of cooking. The project went quite fluently. Ruud gave us
instructions about what to do and we all did our part. We divided the project into different parts for
every individual to do. For example, I had to write a part about the future plans of this project and
the summary.
Every Thursday we had a worldschool meeting with the four of us. In this meeting we discussed the
latest problems and objectives for that week.
It was good fun working with my fellow classmates and I hope our report came out well.
18
Micha Koster
This project that World School has presented us with has given me a chance to help those who really
need it. It really helps to feel like my work actually has meaning, and can actually change other
people’s lives for the better. We started with a slow pace, and along the way, we hit some speed
bumps, but nothing that could completely throw us off course. At the beginning, Ruud directly
showed us that he wanted to lead the group to success. It has been a privilege working with my
group, and for World School. I hope that we concluded to a useful prototype that can help some of
the lesser fortunate in third world countries.
Ruud Wichers Schreur
To start of I would say I had to adapt to this type of report. It is not just collecting text and putting it
into a report in my own words, but you really have to invent the idea and work it out which means it
is totally your own. If I look back at what we started with which were just a couple of tips and the
situation that had to be solved, and when I compare it to what we made now I am really satisfied
with the result. I had not expected it to turn out this way and I have to admit, that in the beginning I
did not really take it serious enough. But once we started to develop an idea I started to enjoy it.
The working in the group went good to. It would be nice if we hear in a couple of years from now
that there really is a system based on our system that helps a lot of people.
19
Annexes
Hello Tom, Micha, Ruud and Costijn,
Great to hear from you!
The assignment about the micro climate in Mauritania is very important for us and even more
important for the local people. When we know how to create a micro climate we can give the
people a chance to cultivate their own vegetables and fruits.
I am looking foreword to work with all of you on this subject. You can send me an email or
call me when you have a question or if you need help. I will try to help you the best I can. I
would also like to be up to date about the progress that you are making.
I already have a question for you: why are we communicating in English?
Greets,
Stephanie Waasdorp
2Unite
20
--- On Thu, 9/30/10, Tom Spierings <[email protected]> wrote:
From: Tom Spierings <[email protected]>
Subject: Worldschool Assignment
To: [email protected]
Date: Thursday, September 30, 2010, 3:31 PM
Dear Stephanie Waasdorp.
Three fellow students in my class and I have got an assignment for Worldschool.
We have chosen the assignment about creating a microclimate.
We are creating this microclimate for the african country of Mauritania.
All of us are interested in this subject because we have physics, chemistry, biology in our
school programme.
Now our assignment is to get in contact with a employee of 2Unite.
We got a paper with your name, email adress and phone number.
We, as a group, will hope to hear from you soon!
Sincerely
Tom Spierings
Micha Koster
Ruud Wichers Schreur
Costijn Blankers
Van Der Capellen S.G
21
From: Ruud wichers schreur <[email protected]>
Subject: Worldschool
To: [email protected]
Date: Wednesday, February 2, 2011, 4:05 PM
Dear stephanie waasdorp
We are the group who are trying to solve the problem about the micro climate. We came up
with some ideas about creating fertilizers out of seaweed. For our experiments we have to
know some things about the materials that are available for the people we work for.
1. Do they drive a car, if so does the car have a 12v battery.
2. Is there any vegetation in the area/ desert that is occupied by the local population
3. is it possible to achieve a ground sample for investigation about the minerals in the ground
and which lack.
we are looking forward for your reply
With kind regards,
Micha, Costijn, Tom and Ruud
From: [email protected]
Subject: Worldschool
To: [email protected]
Date: Thursday, February 3, 2011, 2:18 PM
Dear Micha, Costijn, Tom and Ruud,
Thank you for your email. I am starting to get very curious to the end result of your research.
Here are the answers to your questions.
1. Do they drive a car, if so does the car have a 12v battery.
It is not sure that there is a car available all the time. So if it is a 12v battery that you need, I
would advise you to search another solution for that.
2. Is there any vegetation in the area/ desert that is occupied by the local population
There are some small bushes spread over the area.
3. is it possible to achieve a ground sample for investigation about the minerals in the ground
and which lack.
Last time I was there (may 2010) I collected some ground and put it in a bottle. It is possible
to send it to you if you give me the address. Do you know how you want to investigate it? I
can imagine that it will be quite a difficult thing to do.
Kind regards,
Stephanie
2Unite
22
Hartelijk dank voor het stellen van je vraag op de website van
het Profielwerkstuk Steunpunt van de Universiteit Leiden.
Hieronder staan de gegevens vermeld die je hebt ingevoerd:
--------------------------------------------------------Onderwerp: Omgekeerde Osmose
Vraag: Hallo, Vor ons profielwerkstuk doen wij een speciale opdracht. Dit heeft te maken met het IB
programma dat wij volgen. Het doel van het programma is een probleem in een ontwikkelingsland op
te lossen. Onze doelstelling is de grond van een dorp in mauritianie (een dorp in africa aan de
westkust ) vruchtbaar te maken. Het is een grote zandvlakte. Wij willen dit vruchtbaar maken door
compost van zeewier te gebruiken. Wij hebben een manier bedacht waarop wij op hoge druk het
zoute water eruit kunnen persen maar er blijft dan zout achter. Nu willen wij proberen om iets te
ontwikkelen want met omgekeerde osmose werkt. Dus dat het zoute water uit de plant word
onttrokken. wij dachten dat dit met een semi permeabel membraan en hoge druk wel kon lukken
alleen het blijkt nog niet effectief genoeg. Zou u ons een zetje in de goede richting kunnen geven met
een mogelijke manier om zout uit een plant te onttrekken als dit mogelijk is of dat wij onze manier
kunnen verbeteren? Alvast bedankt! Groeten Ruud Wichers Schreur Van der capellen scholen
gemeenschap
Naam: Ruud Wichers Schreur
E-mail adres: [email protected]
Geboortedatum: 24-06-1993
Opleiding: havo5
Gekozen Profiel: Natuur en Gezondheid
Leraar: Mr. Kalhornn
School: Van der Capellen scholengemeenschap locatie Zwolle
Je hebt je niet aangemeld voor de nieuwsbrief.
Je vraag wordt zo spoedig mogelijk in behandeling genomen.
Met vriendelijke groet,
Steunpunt Coordinator Biologie
23
Hoi ruud,
Vers geoogst zeewier bevat inderdaad relatief veel zout (natriumchloride, NaCl) vanwege het
“aanhangende” zoute zeewater waaruit de planten afkomstig zijn. Echter, de concentratie van
NaCl in de cellen van de zeewierplanten (in het cytoplasma en de vacuole) is veel lager dan
die van zeewater en is min of meer gelijk aan de concentratie in landplanten die in gebieden
leven waarin maar weinig zout in de grond zit. De processen in de cel zouden niet mogelijk
zijn als er te veel NaCl in zat. Om de intracellulaire hoeveelheid zout (natrium ionen) onder
de duim te houden gebruikt de cel zgn. natriumkanalen, speciale eiwitten in het celmembraan
die Na-ionen naar buiten pompen. Probleem van de cellen is dan nog wel om hun zoutarme
waterinhoud niet te verliezen door osmose naar de zout-rijke omgeving van het zeewater. Om
dat tegen te gaan is de concentratie van andere zouten (zoals kalium) en organische moleculen
in het cytoplasma aangepast, zodat de intracellulaire osmotische waarde gelijk is aan die van
het omringende zeewater. M.a.w., het extra zout in zeewier zit vnl. buiten de cellen.
Zeewier wordt op veel plaatsen in de wereld inderdaad gebruikt als compostverbeteraar. Het
bevat veel organische verbindingen en sporenelementen die nuttig zijn als meststof. Er zitten
namelijk niet veel langzaam verterende vezels in. Waar zeewier wordt gebruikt in compost,
wordt het overtollige zout er meestal uitgespoeld met zoet water of door het enige tijd in de
regen te laten liggen. Op dat laatste zal je in Mauritanië wel lang moeten wachten.
Jullie schreven dat je aan omgekeerde osmose dacht om het zout uit zeewier te halen. Ik kan
me niet helemaal goed voorstellen hoe dat zou moeten werken. Omgekeerde osmose kun je
wel gebruiken om b.v. uit zeewater drinkwater te winnen door het onder hoge druk door een
semipermeabel membraan te persen, maar om zout uit zeewier te persen lijkt me niet
uitvoerbaar. Gewoon, spoelen dus! Niet goedkoop waarschijnlijk in een woestijn, maar als je
het een beetje slim uitvoert, kan het misschien wel.
Mijn eigen brainstormpje:
Ik neem aan dat je het zeewier wilt gebruiken als compost voor de landbouw daar. Als er
voldoende zoet bodemwater is op te pompen kun je het zeewier er mee uitspoelen en omdat
dat meestal veel meer water vergt dan het aanhangende zoute water, wordt de
eindconcentratie zout in het spoelwater niet al te hoog. Als de Mauritaanse bevolking een
gewas uitzoekt wat niet al te zoutgevoelig is en bestand is tegen lage concentraties zout, kan
het waarschijnlijk gewoon met het spoelwater worden bewaterd. Het voordeel van een losse
zandgrond is dat het zoute water niet lang in de omliggende grond blijft hangen en daardoor
niet snel zal ophopen, wat zeer nadelig zou zijn voor de groei van planten. Het grondwater
wordt natuurlijk wel langzaam zouter, maar dat zijn zaken die je tegen elkaar moet afwegen.
Netto, gebeurt er dus eigenlijk niet zo heel veel, uiteindelijk komt al het zout uit het zeewier
toch gewoon in de grond terecht. Alleen, de verdeling is anders: er zit geen hoge concentratie
zout meer in de compost en het spoelwater wordt hergebruikt wat er samen voor zorgt dat
landbouw mogelijk is.
Evt. kun je ook door omgekeerde osmose het zoete water weer uit het zoute spoelwater
terugwinnen, maar dat kost door de hoge druk die daarvoor nodig is veel energie. Maar in
Mauritanië schijnt altijd de zon…. wie weet kan die daar in de toekomst wel weer voor benut
worden.
Veel succes met jullie profielwerkstuk!
Huub Linthorst, UHD
IBL, Plantencelfysiologie
Universiteit Leiden
24
Logs
Costijn Blankers
Date
What we have done
Problems we faced
Time (Hours)
3-10-10
Recieved an e-mail
concerning the trip to
delft
None
0
4-10-10
Asked the teacher if we
could go to delft
None
0
7-10-10
Brainstormed questions
for the specialists at delft
None
1/2
14-10-11
Trip to delft
Different as we
expected. Had no
opportunity to ask
our questions
9
21-10-10
Discussed who would
solve which question by
contacting experts
None
2
28-10-10
Thought of different
systems which could
extract salt
It was very hard,
turned out okay,
Ruud made a small
model
3
11-11-10
Mailed the experts with
our idea, she was really
positive, even tried to
sent us a ground sample
The first method
could not work
1/2
18-11-10
Prepared the
presentation for 24-1110
Was difficult
because we have
not got much to
show
3
24-11-10
Presentation
I was alone because
the others were sick.
2
01-12-10
Appointment with our
mentor and from now on
we meet every Thursday
none
1/2
25
with our mentor
15-12-10
Worked out the different
systems which could
extract salt
none
3
22-12-10
Christmas holiday,
emailed our mentor.
None
0
29-12-10
Took a break for new
years.
none
0
06-01-11
Trying to create a new
none
system because the other
on was not that good
2
27-1-11
Designed a new system
because the other ones
would not work in
Mauritania
None
3
03-02-11
Improving the system
Little difficulty
3
10-02-11
Improving the system
Little difficulty
3
17-02-11
Finishing the system
None
2
Creating a presentation
for 02-03-11
Not to difficult
3
03-03-11
We had the presentation
It went really well
3
17-03-11
Started on the report
It was a difficult
because we needed
to think of
everything again
4
24-03-11
Creating parts of the final
report, like introduction.
None
4
31-03-11
Continuing the report
None
3
07-04-11
Finishing up the report
None
6
24-02-11
26
Tom Spierings
Date
What we have done
Problems we faced
3-10-10
Received an e-mail
concerning the trip to
delft
None
4-10-10
We asked the teacher
about trip to Delft
None
7-10-10
We made some
questions for our 2 unite
contact.
None
14-10-11
Trip to delft
I did not attend this
trip. Only two
people could attend.
21-10-10
Discussed who would
solve which question by
contacting experts
None
28-10-10
Brainstorming about
future plans of our idea
Unsure about our
future. We did not
have a clear project
yet.
4-11-10
Created a system which
works with reversed
osmosis
Ruud worked out
the central idea. We
added a bit of detail.
11-11-10
We mailed our contact
and got a lot of
information about the
soil in the country. We
mailed our idea.
Our first methods of
extracting salt could
not be realized
18-11-10
Preparations of our
presentation.
We didn’t say too
much because many
ideas could not be
realised
24-11-10
Presentation of the
progress of our idea
none
01-12-10
Appointment with our
mentor and from now on
none
27
we meet every Thursday
with our mentor
01-12-10 / 22-12-10
Worked on our subject
none
22-12-10
Christmas holiday
Was on vacation to
Cuba
06-01-11
Brainstorming about a
desalination system and
how to make it cheap
and efficient
Unsure about which
materials which we
are going to use
13-01-11
Helped with the design of
a desalination system.
None
20-01-11
Finished first concept of
desalination system
None
27-01-11
Meeting with our mentor
about
None
03-02-11
Enhancing the system
None
10-02-11
Enhancing the system
None
17-02-11
Final adjustments on the
desalination system
None
24-02-11
Preparing for the
presentation for 4 havo
IB and the parents
none
03-03-11
Presentations for 4 havo
IB and parents
I was not at the
presentations
because of a doctors
appointment in
Rotterdam
10-03-11
Orientating about the
final report we have to
write. Giving everyone a
task to do.
None
17-03-11
Started on our report.
none
24-03-11
Writing the report
none
28
31-03-11
Finished all parts of the
report and put it into one
piece
none
07-04-11
Writing summary and
conclusion
none
11-04-11
Final adjustments,
writing the log and
presentation
none
29
Micha Koster
Date
What we have done
Problems we faced
Time (hours)
3-10-10
Recieved an e-mail
concerning the trip to
delft
None
0
4-10-10
Asked the teacher if we
could go to delft
None
1/2
7-10-10
Brainstormed questions
for the specialists at delft
None
3
14-10-11
Trip to delft
Different as we
expected. Had no
opportunity to ask
our questions
9
21-10-10
Discussed who would
solve which question by
contacting experts
None
2
28-10-10
Contacted 2Unite for
questions about the
Mauritanian lifestyle
none
1
4-11-10
Reviewed the system
based on reversed
osmosis.
Found some
designer flaws
2
11-11-10
Mailed the experts with
our idea, Got a lot of
usable information about
our system, the soil and
what the country was like
Our first methods of
extracting salt could
not be realized
1/2
18-11-10
Prepared the
presentation for 24-1110
Because our method 3
could not be realized
we had not to much
to tell
24-11-10
Progress update
presentation
Not much to tell:
1
Read previous…
30
01-12-10
Appointment with our
mentor and planned to
meet every Thursday for
a progress report
none
1
08-12-10
Ruud explained us about
the concept of keeping a
bottle cold with just a
wet towel
none
1
15-12-10
Reviewed Ruud’s draft
concept on desalination
Found some flaws
1
22-12-10
Took a break for
Christmas
None
0
29-12-10
Took a break for new
years.
NONE
0
06-01-11
Let Ruud design a better
concept. He said he had a
feign idea
none
0
13-01-11
Reviewed more of Ruud’s
concept.
Needed to find out if
they had cars
2
20-1-11
Contacted 2Unite to ask
if they had cars in
Mauritania
Our contact told us
we could not use a
car battery because
the local population
did not own cars
1/2
27-1-11
studied Ruud’s design to
find improvements on
the concept that uses the
heat of the sun to it’s
maximum
None
2
03-02-11
Thinking of
improvements for the
concept
None
3
10-02-11
Thinking of
improvements for the
concept
None
3
31
Finishing the system
based on the sun
None
3
Preparing the
presentation for the
parents
It is difficult to talk
for 20 minutes
about our system so
we filled it up with
some facts about
the country
3
03-03-11
Presented our
presentation for 4HT and
the parents. Had no
problem talking through
the 20 min.
No parents showed
up. They figured
they’d see us in
Gouda
3
10-03-11
Review the presentation
and made a plan of who
would do what on the
report
None
1
17-03-11
Started on the report
It was a bit difficult
to tell everything
but we had our log
to check back what
we did
1
24-03-11
Started on the part:
None
2
17-02-11
24-02-11
Finding a solution
31-03-11
Finished my part, and
wrote the conclusion
Took some time to
write the conclusion
for my computer
couldn’t open the
document
4
07-04-11
Writing the personal
evaluation handed in the
draft version to our
mentor
None
1
11-04-11
Shortening the
powerpoint presentation,
making graphs, adding
the last few things such
as bibliography, glossary.
None but it took a
bit longer than we
expected
6
32
Ruud Wichers Schreur
Date
What we have done
Problems we faced
Time (hours)
3-10-10
Recieved an e-mail
concerning the trip to
delft
None
0
4-10-10
Asked the teacher if we
could go to delft
None
1/2
7-10-10
Brainstormed questions
for the specialists at delft
None
3
14-10-11
Trip to delft
Different as we
expected. Had no
opportunity to ask
our questions
9
21-10-10
Discussed who would
solve which question by
contacting experts
None
2
28-10-10
Thought of ideas for
extracting salt
Was harder than we
expected it to be,
could not just find
answers on the
internet
3
4-11-10
Enhanced our idea a bit
and resulted in a system
based on reversed
osmosis
none
2
11-11-10
Mailed the experts with
our idea, Got a lot of
usable information about
our system, the soil and
what the country was like
Our first methods of
extracting salt could
not be realized
1/2
18-11-10
Prepared the
presentation for 24-1110
Because our method 3
could not be realized
we had not to much
to tell
24-11-10
Presentation of the
progress of our
I had a doctors
appointment so I
2
33
could not be there
01-12-10
Appointment with our
mentor and from now on
we meet every Thursday
with our mentor
none
1
08-12-10
I was thinking about a
possible solution and
remembered a method in
which you could keep a
coca cola bottle cool in
the sun. On which our
cooling system is based
and wrote it out
none
2
15-12-10
Worked out a concept
how to evaporate water
and cooling it down and
split salt and water
none
2
22-12-10
Christmas holiday
None
2
Sent an e-mail to our
mentor with our progress
so far, we have an idea of
how our system could
work
29-12-10
Took a break
none
0
06-01-11
Trying to invent a system
in which we would use
water to condensate and
let it flow to the other
side
We do not yet know
how it is going to
look like but I make
it at home
2
13-01-11
We developed an idea
which uses the hot air to
rise and collect it to a
central point
None
2
20-1-11
Finished the system
based on a peltier unit
and mailed our contact
Our contact told us
we could not use a
car battery because
the local population
1
34
could not afford a
car
27-1-11
Designed a system based
on the heat of the sun
and a pyramid roof
None
3
03-02-11
Enhancing the system
None
3
10-02-11
Enhancing the system
None
3
17-02-11
Finishing the system
based on the sun
None
3
3
24-02-11
Preparing the
presentation for the
parents
It is difficult to talk
for 20 minutes
about our system so
we filled it up with
some facts about
the country
03-03-11
Presentation for the 4HIB
scholars and parents. It
went really good, even
better as I expected. We
could talk for 20 minutes
and were well enough
prepared
Only one small thing
that could have
gone better and that
was that we brought
an USB stick with us
because the internet
of school went down
3
10-03-11
Review the presentation
and made a plan of who
would do what on the
report
None
1
17-03-11
Started on the report
It was a bit difficult
to tell everything
but we had our log
to check back what
we did
3
24-03-11
Split the system up in
different parts to make it
easier to understand
None
3
31-03-11
Finishing my part of the
report
None
2
35
07-04-11
Writing the personal
evaluation handed in the
draft version to our
mentor
None
1
11-04-11
Shortening the
powerpoint presentation,
making graphs, adding
the last few things such
as bibliography, glossary.
None but it took a
bit longer as we
expected
6
36