UNIVERSITYOF NAIROBIKENYASCIENCE CAMPUS DEPARTMENTOF PHYSICS Aproject Report on Generating Water for Survival in The DesertSubmittedtowards fulfillment of bachelor of education science NAME:KORIR HILLARY CHERUIYOTREG.NO: E37/4044/2014SUBMITTEDON:DeclarationpageI herebydeclare that this project research is my own work and has not been submittedfor research at any other university.Name:Korir Hillary Cheruiyot.Reg. no:E37/4044/2014.
Signature:__________.Date:______________.Thisproject research has been submitted with my approval as the supervisor:Name:Dr. Sebastian M. Waita.
(PhD), Department of Physics Coordinator, University of Nairobi.Signature:____________.Date: ________________. ABSTRACTThisproject research involves a summary of work aimed at generating water forsurvival in the semi-arid areas. The research is aimed at addressing challengesfaced by soldiers and people who tour desert places and in the long run theirstored water run out. Many of them may become weak as a result of dehydration,hence may distract them from concentration on their work and may end up dying.This can be solved by using the locally available materials to generate waterthrough solar still to sustain them for some time. This project may bedeveloped to bring a more lasting solution to the problem faced by peopletouring or working in semi-arid areas.
Evenhealthy water sources can contain harmful bacteria that can cause humans to beill and loose more body fluids. Dehydration strikes quickly and overcome theminds irrationality and at the same time the volume of the blood in the bodyreduces drastically. Because of inadequate supply of blood in the blood vesselsthey then start to shrink followed by nausea, headaches,muscle cramps and dizziness quickly follow. Emergency techniques are then required to safe thesituation, this emergency technique is solar still which is the readilyavailable.
Solar still is also known as underground still or below groundstill.It hasbeen proven scientifically that human beings can stay without water for atleast 3 days; this is possible if the temperatures moderate. It has also beenproven reduction of water in the level of water in the body reduces normalbodily performance and also the mental performance. This therefore reduces theability of the person to be able to overcome the extreme temperatures andconditions hence may not achieve their goal.
Undergroundstill uses the principle of greenhouse effect. In this process the sunlightheat passes through the clear plastic paper that hits the humid soil. The waterthen evaporates in form of vapor, hits the polythene barrier and condensesbelow it then drops to the collecting jar. This water is purified and almost90% clean hence can be fit for drinking if no other water is available. TABLE OF CONTENTS LIST OF FIGURES1. Figure1: Sketch of underground still 2. Figure2:3.
Figure3:4. Figure4:LIST OF ABBREVIATIONS AND SYMBOLS1. l-Liters.2. m-Meters.3. cm-Centimeters.4.
m2-Square meters.5. Kw -Kilo Watt.6. Km –kilometer.7. K –Kelvin. CHAPTER ONE: INTRODUCTIONSolarstill is a simple way of distilling water using the heat from the sun which thendrives water through evaporation from humid.
Solar stills are in two ways; pitstill or underground stills and box stills. We are going to focus onunderground stills. Impure water is present and in the humid soils which areoutside the container. The water from the humid soil is evaporated by radiantheat from the sunlight passing through the transparent polythene bag.Solarstill replaces the way nature makes rain. The sunlight heats the water to apoint of evaporation, the water evaporates in form of water vapor, thencondense on the polythene bag and drop to the at the weighted center to thecontainer collecting. This process removes impurities in such as heavy metals,micro-organisms and even salts.
This makes the water pure even more then rainwater.Placeswith greener grass or plants downstream is rich with moisture since the morethe greener the young plants are, the more they consume water and hence theless green they are, little they use water. The ground that supports theseplants is very rich in moisture hence giving another best place to construct anunderground still.Theseplaces rich in moisture can be found easily without using more technical waysbut just nature. One of the ways of finding these places is by just lookingaround these places which are mostly found downstream or valleys or down themountains.
These places are the best since most plants are found there thanhigher places which mostly contain rocks and loose sand. Anotherway these places could be determined is by following animals, birds and insectsthat are found in the desert. Animals that mostly run down the valley go towhere the water is or where they have been, if there is no water then moisturein the soil could be present.
This is same to the case of the birds. There isan interesting idea about the insects which are mostly bees they travel instraight line from the beehive to where water could be found.Thispeople who visit semi-arid places carry with themselves water to be used,however, it may be impossible to carry water for many days, and survivalsituations may create an unforeseen demand for water. If they are travellingfor 2 weeks, each person will require 25 L of water for drinking only which ismultiplied by the number of people to travel. Since the body requires at least 1Lof water each day, if this demand is not met, dehydration will result, leadingto heat exhaustion, heatstroke and death will occur within some days.This canbe solved using simple materials that are cheap, portable and easily found.
Theaim of this research is to generate water for survival that can be done toenable the people to look for more reliable water sources. CHAPTER TWO: LITERATURE REVIEWSyria isone of the countries in the world within arid areas. They use solar stills togenerate water or purify the available solar saline water. Syria has high solarisolation. Hence one of the cheapest ways to have the water fit for drinking isby solar still. In implementing use of solar still Syria in November 2010designed, manufactured and piloted three similar solar stills for a day and itwas found that the stills produced water that were fit for drinking. Itcondensed and purified the saline humid soil.
(J.Lindblom, Renewable EnergySystems, Lulea University of Technology, Lulea 2010)Therefore;since plants and many animals survive in desert then there is a possibilitythat human beings who visit desert places can survive too. Since animals andplants need water for them to live, then there is plenty of water in the desertand people ought not to die because of dehydration in the desert. Innovativeways need to be put in place so that they can help anyone stuck in the desertget water.
Dehydrationsets in quickly in the arid areas due to intense scorching sun. This is due torampant loss if excretion from bodies of human beings. If one is found in suchsituation in the desert, the simplest way of getting water is by condensationof water vapor. The available sources where water can be condensed are dryriver beds. (WikiHow)There aresome factors that affect the performance of solar stills, some of them are;intensity of solar, water-transparent polythene bag, temperature differences,ambient temperature, among others. The modes of heat transfer in involved insolar still include; radiation which comes from sun and requires no medium oftransfer, this hits the humid soil.
The water in the humid soil reaches thetemperature of evaporation and evaporates immediately. CHAPTER THREE: THEORETICALBACKGROUND The efficiency of the solar heat on one solarpit approaches 60% all day. This is at its optimum at noon. The intensity ofthe sunlight energy is utilized in vaporization of water. Solar still works ontwo processes; the first process is evaporation, once the still is ready it isallowed to stay in the sun, and then it absorbs short wave radiations energy.
Water in the still gets heated, as the temperature of the water increasesliquid water is converted to gaseous form which then evaporate towards thetransparent plastic paper leaving solid residue behind. This is followed bycondensation process, where the evaporated water hits the plastic paper andslowly condenses on the paper forming droplets of clean water. This water thenrolls down to toward the weighted center where they drop to the collectingcontainer.The waterproduced is clean since no impurity can turn into gaseous state and evaporate.This natural water purification has PH level balanced. 1.
Sunlight radiations.2. Support stick.3.
Water droplets.4. Evaporating water.5. Collecting container.6.
Collected water.7. Supporting stone.8. Transparent polythene bag.Figure 1-Asketch of underground still Just like other stars the sun iscomposed atoms and nuclei occupying approximately 94%, helium covering 5.9% andother elements take 0.
1%. The sun is in gaseous form having a mass of about2X1030 kg and radius of about 7X105 km. When compared tothe earth’s radius of approximately 3.3X105 km the sun’s radius ishigher.
The sun produces energy at a rate of 3.8X1023 Kw. With thesun being approximately 1.5X108 km from the sun it taps a fractionof the energy produced. Through fusion furnace most of thisenergy is produced then transferred radially outwards through solar energywhich radiates at a temperature of approximately 5800 K. Electromagneticradiations emitted from the sun are converted to other forms of energy.
Theradiations reach the earth either directly or by reflection. Short waveradiations are reflected back to the space but those absorbed are re-radiated.Some sunlight radiated from the sunpass through the atmosphere while others are absorbed by clouds, pollutantsfrom power plants among others. The particles on the atmosphere reduce 10% ofthe radiations.
When it is cloudy the reduction can go up to 100%.Still is used to draw water fromsoil and from plants. When constructing the belowground still a place withsufficient moisture ground is required, these places in desert places could bedried river beds, oasis, or dried places which formerly contain water. Theseplaces have some sand or soils that contain moisture. These are the best placesin which underground still can do since it’s an open ground having sufficientsunlight heat.Condensations of water in solarstills by themselves are used as supplement water source and thus may not be areliable water source. They should not be relied on to provide daily water usedin daily activities such as bathing, washing among others. The still measuring40 cm wide and 30 cm deep produce 100 ml up to 150 ml of water per day.
These siteneeds to be in an open ground where sunlight is readily available. Sunlight isthe second most important commodity after moisture. Sunlight is needed toevaporate the moisture. The sunlight needs to be as scorching as possible to beable to evaporate the moisture from the soil and also the plants to be able totranspire. The experiment need not to be in a shade or in place withoutsufficient sunlight.
The nextstep is to start the process of condensing the water that is available. Theground with moisture is the primary source of water, and the secondary sourcesof moisture are leaves from the plants. When the sun heat hits the wet soil andgreen plants water will evaporate. The evaporated water gets trapped on thelower part of the transparent paper. They are condensed here since the vaporsencounters the paper which is cooler that the temperatures inside the hole.They form dropletswhich collect towards the center where a stone has been placed at the center ofthe paper. This stone helps to bring the condensed water together as thy dropinto the collecting jar.
The transparent paper has been fully covered by theedges so that no air is able to escape. CHAPTER FOUR: MATERIALS AND RESEARCHMETHODOLOGY MATERIALS The following materials were used to constructan underground solar still:· 1L Container.· 1 m2 transparentpolythene paper.· A Spade.· Pieces of 4-inch sticks.· 100ml graduated cylinder. RESEARCH METHODOLOGYFinding water for survival by condensation inthe desert is one amongst ways of getting water in the desert. The research wascarried out in an open place with a lot of sunlight in two ways and the followingprocedure was followed:Method1· A round still with a diameter of 60 cm wideand 50 cm deep was dug and soil was removed and placed outside close to thehole.
· The 1L container was placed at the center ofthe hole.· The hole was then covered with the transparentpolythene bag. Then the 4-inch sticks were pierced through the transparentpolythene at an interval of 10cm all-round the hole. Soil was then used tocover the remaining spaces left by the sticks so that no evaporating moistureescaped from the hole. · A smooth stone was then placed at the centerof the polythene bag from the outside so that it hangs and forms an invertedcone over the container.· The project was left on the field for 48 hourson hot sunny days.
Method2· A round hole with a diameter of 60 cm wide and50m was dug and soil was removed and placed closed to the hole.· The 1L container was placed at the center ofthe hole and around it was green leaves with some young plants uprooted fromthe surrounding. · The hole was then covered with the transparentpolythene bag. Then the 4-inch sticks were pierced through the transparentpolythene at an interval of 10cm all-round the hole. Soil was the used to coverthe remaining spaces left by the sticks so that no evaporating moisture escapedfrom the hole. · A smooth stone was then placed at the centerof the polythene bag from the outside so that it hangs and forms an invertedcone over the container.· The project was left on the field for 48 hourson hot sunny days. CHAPTER FIVE: RESULTS AND DISCUSSIONRESULTS After covering the hole for 10 minutes, thetransparent polythene bag had traces of some white substance from the bottom.
And the transparent paper was no more transparent.After 1 hour of experiment some lines formedon the lower part the leads to the center of the paper where a weight had beenplaced. Water droplets could be seen on the transparent paper.
All along from the 1st hour of experiment tothe 48th hour of the experiment water droplets formed and the morewater droplets formed the more the lines headed to the center stone.After the elapse of the 48 hours, the volumesof water that had been collected were measured. It was found that the experiment without theleaves produced 200 ml while the one having the green leaves produced 230 ml ofwater. At the end of the 48 hours the leaves that hadbeen placed inside the hole turned brown in color and the soil inside the holewere dry. This is an indication that water had been drawn from both the soiland the green plants. DISCUSSIONThe white substance that formed below thepolythene was water vapors that had evaporated from the walls of the hole andthe green plants. They are in form of water droplets but their size is toosmall.
They were the first to encounter sunlight heat.After the 1 hour the exposure to sunlight is moreintense and more evaporation takes place.The upper part of the polythene is cooler thanthe bottom. So, it acts as sheet to cool the water vapors.
This is why theydrop after getting to the paper. The experiment without leaves were able torecord a slightly lower volume that the part having the leaves. This wasbecause the leaves were able to produce 30ml of water. Leaves were added sothat they increase the surface area over which the water can be drawn from.Nevertheless, the volume of water collectedwithout the green plants is sufficient given that the there are many of suchholes.The water droplets collect themselves belowthe cone shaped plastic paper and then flow downwards to the tip of the coneshaped paper where they drop to the collecting container. CHAPTERSIX: CONCLUSIONS AND RECOMMENDATIONSCONCLUSIONSOne can drink the collected water by use ofstraw that run through the surface but without disturbing the project.
Thestraw runs up to the bottom of the collecting container. The other way can bewaiting until the end and then collect all as you empty them into bigger waterstorage.Underground solar still is one of the waysthat have been used to purify water for safe drinking. As water evaporates fromthe humid soil and transpire from the leaves. It leaves behind salts, heavymetals and micro- organisms.
This brings up water that is safe for drinking. However,this water is in small volume that may not sustain an average family. It’s ableto sustain travelers who have no other source of water.Many underground stills have to be dug inorder to increase the volume of water that is being collected. Since a singlehole provide an average of up to 220 ml of water maximum when the soil is veryhumid.
This volume may reduce to 200 ml minimum if the soil is less humid orlow sunlight energy. Distillation by solar does not kill some harmful chemicalsand some bacteria because the water is not heated up to boiling point.The underground still requires very littlemaintenance, it is also portable. RECOMMENDATIONSThe water obtained in an underground stillmaybe of low volume, but the more the stills the more the volume of watercollected is increased. This project is the best suited when the sunlight heatis hottest. The transparent paper should not have holes on its surface.
Ifpresent then water vapor may escape through them.REFERENCE1. ErVinayChauhan/solar-still-project-report.
2. FM21-76_SurvivalManual.pdf.3. hawale3/solar-still-32904283.4. desertUSA.comss