Sustainable development

WATER PURIFICATION TECHNOLOGY IN ZAMBIA

Project Work 2010/2011 Kungsholmens Gymnasium

Beatrice Hallmark EN3A

Mentor: Carl Lilja

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Abstract

The provision of clean water is an important issue to solve and there is no one solution,

thankfully. Different areas have different problems and resources and no one solution can be

applied to all. In developed countries, water is often pumped from a nearby lake or from

groundwater and extensively treated in several stages in large plants to ensure safety. Water is

commonly filtrated, sometimes in several stages with chemicals added to completely

eliminate the smallest particles of pollutants and to speed up the process. Chemicals are then

filtered out again. Filtration in various forms is so far the only method to clean water, apart

from UV-purification, whether it be a traditional slow sand filter or a reverse osmosis system

or a modern, large scale filter in a water-purification plant.

In developing countries such large-scale infrastructure does not exist, thus polluted water is a

big problem. Charities are very active in combating this problem, especially in rural areas,

helping villages to install sanitation facilities and groundwater pumps or water purification

technology. The focus of this paper will be on smaller, household systems for purifying water,

looking at existing appropriate technology for purifying water in developing countries, with a

special focus on Zambia in sub-saharan Africa. Background is also provided on water, the

diseases associated with unsafe water and their effect on a population.

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Research Question

What are the current resources available and issues associated with acquiring clean drinking

water in Zambia, and what is therefore the best method for purifying drinking water in rural

and urban areas in Zambia, from the point of view of low cost, efficiency and environmental

sustainability?

Methodology

Research was conducted in books and in large part on the internet. Institutions such as the

WHO and NWASCO (National Water Supply and Sanitation Council, Zambia) were reached

on the internet and their reports and publications were used. Most of the information on

Zambia was obtained from personal contact with representatives of NWASCO and the

Zambian NGO Village Water Zambia, via email. A visit to Zambia was also made with

students and teachers from Kungsholmen’s Gymnasium in March 2011. During this visit we

had the opportunity of personally interviewing the founder of Village Water Zambia.

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Contents

WATER PURIFICATION TECHNOLOGY IN ZAMBIA 1

Abstract 2

Research Question 3

Methodology 3

Introduction 5

Water 6 What is clean water? 6 Water-related disease 10

Cholera 12

Water purification 13 Filtration 13 Chemical disinfection 14 Reverse osmosis 16 Systems and developments 17

SODIS-Solar Disinfection 17

LifeStraw 18

Nano-filter 19

Ceramic water filter 19

Bio-sand filter 20

Kanchan Arsenic filter 21

Water in Zambia 22 Available water sources 22

Potential natural sources 22

Piped water in kiosks 24

The impact of inadequate water and sanitation 27

Conclusion 29

Sources 31 Tables and Figures 33 Bibliography 34

Appendix 34 Notes From the Interview with Village Water Zambia 25 March 2011 34

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Introduction

One might think that adequate water and sanitation are not much of a problem, compared to

war, natural disasters and global warming. After all, water exists in plentiful supply; one just

has to go and get it. That is true. Although less than 1% of the water on this blue planet is

fresh water suitable for human use and a lot of that is inaccessible, frozen in polar ice caps,

the water we do have is enough to support everyone. Then why does not everybody have

enough water? The water we do have is unevenly distibuted across our planet. Some people

have much more water than they need; lots of rain settling in rivers and lakes, sometimes even

harming us when there are floods. And some people do not have enough; in dry regions there

is little rainfall. The rain that does fall quickly gets absorbed back by the thirsty atmosphere

and in dry soil there are not enough plants to bind water. Dry ground is also often

impermeable, causing precious water to run off.

Climate change furthers these discrepancies. When global temperatures rise climate becomes

more extreme, increasing climatic extremes and causing more natural disasters. Polar ice caps

melt and precious fresh water is lost into the salt sea, sea levels rise and threaten to cover

many coastal towns. Water trapped in snowcaps in the mountains, for example in the

Himalayas, is normally cyclically frozen and melted and released gently into rivers for human

consumption. Higher temperatures might turn this perfectly balanced cycle dangerous,

causing flooding. In dry areas water is already scarce, deserts such as the Sahara are

expanding, rendering more areas uninhabitable. This is why we have to protect the water we

do have, to ultimately protect ourselves.

All water we have is a finite, but luckily abundant, resource. It constantly moves between

earth and atmosphere in the water cycle; accumulating in the atmosphere from evaporation

and plant transpiration and coming back down as rain, where some of it evaporates

immediately and some is kept for a time. The water we can readily use comes from two

sources; surface water in rivers, lakes and smaller reservoirs, natural or man made (dams), and

groundwater.

Contamination is a great risk to our water; especially surface water where pathogenic bacteria

and microbes flourish and dissolved dirt can make it turbid. Groundwater is often safe from

these pathogens because it has been naturally filtered through rock. Chemical contaminants

such as heavy metals from industry, synthetic fertilizers and poisonous minerals are also very

dangerous and because their particles are often very small, they can put groundwater at risk.

This is why providing clean water is a problem that must be solved, to help the whole world.

If we reduce mortality from drinking polluted water, we can lower child mortality and raise

life expectancy. It is a problem on a massive, global scale, but locally it is not difficult to

solve. Providing clean water and educating people locally is easy. This could in the long run

help avoid over-population, as poverty and mortality are reduced, because poverty is often

associated with larger families. Water-related diseases are often very easy to cure and even

easier to prevent, but knowledge of the dangers of polluted water is often lacking. Fewer

people sick and dying from water-related diseases will reduce pressure on already over-

stretched healthcare systems and means that there would be more economically active people

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helping the national economy grow. This will also help the global economy. Knowledge and

cheap, clean water are easy to provide and make a great difference very quickly in people’s

lives. When health and knowledge improve, so does economy, empowering people to make

the rest of of the difference themselves.

When considering various systems for purifying water, some basic concepts are taken into

account. Appropriate technology is the most important concept; it entails technology that is

easy to use and repair with locally available material and does not need expert handling. Local

people can with a bit of help set it up themselves and maintain it with locally available

material. A good system also needs to be cheap and reliable without endangering the

environment; either by risk of leaching chemicals into nature or through difficulties with the

disposal of used systems: non-degradable materials or chemicals.

Water

What is clean water?

When you think of cleaning water you might say: “well, just boil the water to steam and

condense it again, and it will be clean”. That is true, but such water is distilled and will never

serve as drinking water. Water used for human consumption contains some minerals and salts

that are essential for our bodies to function. It picks these up from earth, sand and rocks on its

way from its natural source as it runs through mountains and over land to where we pick it up

and drink it. These minerals include Calcium (Ca), Magnesium (Mg), Potassium (K), Sodium

(Na) and Flouride (F). Calcium is important for bone development, Potassium is needed in

muscles and nervous system and Magnesium might help protect against cardiovascular

disease although most water contains very little of this. Consumption of a litre per day of

good quality mineral water may provide some of the recommended daily intake of Calcium

and Potassium.1 Drinking water should not be relied upon as a single source for a sufficient

intake of these minerals, but they affect taste and may have certain health benefits. Drinking

water is also slightly alkaline, whereas pure H2O is pH neutral, distilled water should not be

drunk regularly. Sodium and Flouride are dangerous, even lethal in high concentrations,

although such concentrations are rarely associated with drinking water. Too much Sodium can

lead to dehydration2 and too much Flouride can cause bones and teeth to become brittle; it is

also possibly linked to Down’s syndrome and Alzheimer’s disease3. Too much Flouride is

especially dangerous to children. Below are the limits for water set down by the Codex

Alimentarius commission, a group consisting of the WHO and FAO (Food and Agriculture

Organization of the UN) who set down limits for ingredients in all types of food.

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Table 1: Health-related limits for certain substances as recommended by the Codex

Alimentarius

For Bottled water sold as “Natural Mineral water”:

3.2.1 Antimony 0.005 mg/l

3.2.2 Arsenic 0.01 mg/l, calculated as total As

3.2.3 Barium 0.7 mg/l1

3.2.4 Borate 5 mg/l, calculated as B

3.2.5 Cadmium 0.003 mg/l

3.2.6 Chromium 0.05 mg/l, calculated as total Cr

3.2.7 Copper 1 mg/l

3.2.8 Cyanide 0.07 mg/l

3.2.9 Fluoride See section 6.3.2

3.2.10 Lead 0.01 mg/l

3.2.11 Manganese 0.4 mg/l

3.2.12 Mercury 0.001 mg/l

3.2.13 Nickel 0.02 mg/l

3.2.14 Nitrate 50 mg/l, calculated as nitrate

3.2.15 Nitrite 0.1 mg/l as nitrite

3.2.16 Selenium 0.01 mg/l

“If the product contains more than 1 mg/l of fluoride, the following term shall appear on the label as

part of, or in close proximity to, the name of the product or in an otherwise prominent position: “contains fluoride”. In addition, the following sentence should be included on the label: “The

product is not suitable for infants and children under the age of seven years” where the

product contains more than 1.5 mg/l fluorides”. 4

Bottled water that is sold to consumers is required to follow very stringent limits, perhaps

more so than water in nature that is still considered drinkable, but these limits are a good

yardstick. Water for drinking or sanitation purposes should contain no bacteria,

microorganisms or viruses.

Water that we commonly see as dirty and what we imagine as dirty water is turbid (cloudy).

This is due to suspended solids, sand and clay dissolved and suspended in the water and

sediment from the bottom that can get disturbed by aquatic animals such as fish,

phytoplankton and algae growth can also cause turbidity. The measure of the amount of such

suspended solids, Total Suspended Solids (TSS) can be quite difficult to determine but for

drinking water purposes, turbidity is obivously important. Turbidity is a measurement of the

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degree to which water loses its’ transparency due to

suspended solids, it is measured in units of Nephelometric

Turbidity Units (NTU). The WHO recommend that

drinking water does not have a turbidity above 5 NTU,

preferably closer to 1 NTU.5 Turbidity is measured with

a secchi disk (Figure 1), a black and white disk which

is lowered into water with a rope, the measured depth at

which it can no longer be seen gives an indication of

the NTU of the body of water.5 Turbidity is in itself not

a threat, but drinking cloudy water is not very nice.

Suspended solids also increase the risk of pollutants,

giving bacteria, viruses, heavy metals, chemicals and other

pollutants ample opportunity of attaching to the suspended

particles.

The roman architect and civil engineer Vitruvius (1st century B.C) used the following criteria

to determine water quality. Good quality was determined if: (1) people living nearby the

source were healthy, (2) if droplets of water left no traces on bronze vessels, (3) water left no

sand or other residue after boiling, (4) green vegetables could be cooked quickly in the water

and (5) running water was clear and aquatic plants had not taken root.6

Figure 1: Secchi disk

The secchi disk, lowered into a body

of water to determine turbidity

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Global water resources

Figure 2: Global water resources

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As one can clearly see, there is plenty of water on this planet (Figure 2), the top left hand

picture shows total renewable water resources per inhabitant; most countries are covered by

the two darker blue shades, 1700-5000 cu m per person or even more. As can also be seen in

the top right hand picture, most countries use only 10% or less of their possible renewable

resources, this includes Zambia. The centre picture shows that only a few countries are

currently suffering from physical water scarcity: these areas include the coast of northern

Africa, the Arab Peninsula, parts of the southwestern United States and northern Mexico and

parts of the Middle East, northern China and eastern Australia. Asian countries around the

Black Sea and the Caspian Sea, parts of central India, South Africa and western Mexico are

expected to suffer from physical water scarcity soon if infrastructure and the way resources

are used are not improved. The bright orange areas, the broad belt across central Africa of

which Zambia is definitely a part, some of the Far East around northern India, Bangladesh and

the countries south of China and western south America, are suffering from economic water

scarcity. These are also the areas that we associate with the developing nations of the world.

Economic water scarcity means that there is limited access to water despite the fact that there

are plentiful natural resources. It probably means that most of the water is in rivers and

smaller surface reservoirs is polluted and that there is limited infrastructure in place to provide

water for human use. Plentiful water supplies in some countries can also make up for shortage

in other countries; the bottom left picture shows global water flow, which countries are

importing and exporting water and how much. According to this picture Zambia might be

importing a small amount of water, despite the fact that they have no physical water

shortages. This could be due to the lack of infrastructure needed to utilize existing resources,

leading providers to import water instead. However, it is most likely that Zambia does not

import any water, thus is put in the 0-5 category. The truth is that there is a lot still to be done

to get Zambian water to people who so badly need it; for example, groundwater could be

pumped up. In some countries over-exploitation of groundwater has led to dangerously

sinking water-tables - the Chinese city of Beijing is at risk of sinking because of a reduced

water-table below.6So far, this is not a problem in Zambia because as yet very little water is

used and what is used is eventually replenished by rain. Surface water sources can also be

used if sufficient water purification is in place.

Water-related disease

The risk of disease is very high when clean water and adequate sanitation are not available.

Contaminated water contains bacteria and viruses that cause diseases and may contain

poisonous chemicals. Suspended solids, small particles of dust or earth that make water

cloudy or brown are likely to carry such pollutants are therefore undesirable. Certain metals

and minerals i.e. Pb (Lead) and Arsenic (As) are toxic and others are dangerous in high

concentrations. Chemicals often come from the leaching of fertilizer and pesticides, for

example nitrate. Viruses and bacteria can cause diarrhoeal diseases such as Cholera, Typhoid

fever, E – coli infection, Hepatitis A, Polio and Legionellosis (Legionnaire’s disease). This is

an acute issue especially in developing countries. These diseases are perfectly treatable, but in

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these countries they may be lethal, due to the lack of sufficient medical care. A vicious circle

forms when waste is disposed of and contaminates water. One of the most common

contaminants in developing countries is bacteria from faecal matter that enters the water when

it cannot be disposed of properly.

In developing countries medical care is often limited and already highly strained. Hospitals

are small with limited resources and people often have to travel vast distances to reach them.

A lack of knowledge is also a great problem-people simply do not know of the risks of

contaminated water or may have no option for acquiring water than a from contaminated

source. The mother of a sick child may well continue giving it contaminated water in the hope

of curing, not knowing what is causing the illness or that the water is contaminated.

The risk of disease is not only from drinking contaminated water. Water-related diseases are

commonly classified depending on their relation to the use of water:

Water-borne diseases are the most widely known; caused by organisms that can survive in

water (such as E.coli and salmonella and viruses that cause Hepatitis A and Polio). These

pathogens are easily ingested when contaminated water is drunk. Due to the short life cycles

of bacteria and viruses, a small number can multiply very rapidly, spreading the disease.

Water-washed diseases such as some diahorreal diseases and skin-and eye infections such as

scabies and trachoma, can easily take hold when sufficient clean water is not available for

personal hygiene. When water is scarce, washing often takes a back seat to the need to drink.

Water-based diseases are such that parasites that spend part of their life cycle in water can be

ingested when washing, swimming or drinking the water. Examples are intestinal worms and

Schistosomiasis (Bilharzia).

Water-associated vector-borne diseases: Water provides a habitat for many insects that carry

diseases. For example mosquitoes that often breed in still water. The most well-known and

dangerous are malaria and yellow fever.7

Inadequate sanitation is inextricably linked to the problem of providing clean water. Improper

disposal of waste can easily contaminate surface water sources and will contaminate areas

where people move on a daily basis, for example where children play. Washing hands after

each possible contact with faeces is unlikely and disease is rife where precious clean water is

limited. It will be used for drinking instead of washing. According to WHO, the minimum

amount of water a person needs to survive is 5 litres per day, the limit for reliable health is

about 30 litres.6

Diarrhoeal diseases are the most common in developing countries because they are directly

related to inadequate water and sanitation facilities. They are easily cured by drinking clean

water and replacing lost body salts, often by administering a salt-solution. Eating plenty of

good food would help this as well. These are all things that we take for granted but are often

not available in developing countries.

Surface water in rivers and Dambos (see p. 21) in Zambia is often highly contaminated, but

wells are not much better if they are not sealed. Both in urban and rural areas hand-dug

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shallow wells are common. These are contaminated when waste is disposed of and people

defecate openly nearby, this quickly leaches into the water. Especially in the rainy season,

water-borne diseases are rife, when rain mixes with waste and leaches into the nearby river,

open wells flood and waste runs into the well. Water-borne diseases are practically

unavoidable in rural areas, in urban areas there are at least water-kiosks, but diseases are a

reality there as well, since people live so close together with shared, inadequate sanitation

facilities. The diseases most commonly found are Thyphoid fever, Dysentery, both diarrhoeal

diseases resulting from bacterial infections; Trachoma, an eye infection caused by bacteria;

Schistosomiasis, a parasitic infection very common in Zambia, and Cholera.

Cholera

“When the rain comes - Cholera comes.” (Pers. Comm. Village Water 2011) Cholera is the

worst diarrhoeal disease, with seven recorded pandemics in the last 200 years. In acute cases,

death can occur within 3-4 hours, although 90% of cases are mild and therefore easily

confused with other, less virulent diarrhoeal diseases.7 Acute cases cause severe, watery

diarrhoea, vomiting and muscle cramps. Skin becomes cold and withered. Patients become

rapidly dehydrated and need rapid treatment.7

Originally it was thought to be an Indian disease, and it did originate in Asia, but with mass

movement of people between continents with air travel, motorways and international trade the

hardy bacteria spread across the world. The Cholera bacteria can survive in clean tap water

for up to 30 days and tolerate refrigeration. They can live in food, although there is little

evidence that the international food trade has contributed to spreading Cholera.

The last pandemic, which started in 1961 in Indonesia, is still going on. It ravaged Asia for a

decade and then reached Africa by 1971. It receded slightly in the later 1970’s but increased

again in the 1980’s.8 In South America, Cholera had been defeated since the 19

th century but

reappeared in Peru in 1991 with over 320,000 reported cases in Peru alone, by far the hardest

hit in the Americas. Thanks to swift action from authorities with warnings issued to families

and medical help provided, there were only 3000 deaths in Peru.7 The year 1991 also saw a 9-

fold increase in Cholera cases in Africa.7 Nigeria was the hardest hit with nearly 60,000 cases,

from no reports at all in 1990, followed by Zambia and Ghana with 13,000 cases each.

Although the African and South American outbreaks both involved the same strain of the

bacteria, the El Tor, Africa reported about 10% fatalities, almost ten times that of South

America.7 The El Tor strain is less virulent than the Asian variety, but is still a dangerous

disease and remains a serious issue in developing countries.

The first modern record of Cholera in Europe occurred in the 1830’s, reaching Russia and

Germany from the Middle East. France was struck in Paris in 1832 and there were several

outbreaks in London during the 19th

century. Sanitation was very bad, with sewerage disposed

of straight into rivers, streams and stormdrains. In crowded, poor areas, sewerage was often

emptied from windows straight into the street below. The situation is little better in many

slums in developing countries today. London physician John Snow first identified sewage-

contaminated water as the transmitter of Cholera in 1854. In 1883 German scientist Robert

Koch managed to identify the Cholera bacteria Vibrio Cholerae. At last, governments

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recognized the importance of clean water and sanitation. Outbreaks of Cholera were the spur

of major investment in water supply and sanitation in several European cities and Cholera

soon receded. Later, in 1991 there were only minor outbreaks in Romania and Ukraine, with

226 and 75 cases respectively and only 9 deaths in Romania.7

Water purification

Filtration

Most, if not all, water purification systems contain a filter stage. These filter out large things

from sewage water, like cotton wool and condoms that should not have been thrown down the

toilet in the first place. Filters can also remove smaller particles like silt and suspended solids;

dissolved ions and some filters catch bacteria and viruses. Filtration is the most widely used

method in developing countries. One of these filtration methods is the sand filter. As the name

implies, sand filters filter water through sand and gravel, thus mimicking nature as

groundwater percolates through the ground. There are two types of sand filters: a rapid sand

filter and a slow sand filter. Rapid sand filters filter water through sand, but speed up the

process by using chemicals as well. Rapid sand filters may use flocculation (see p. 15) with

aluminium and iron. Slow sand filters however, use no chemicals or electricity to function,

but they are often large and require large areas if used municipally. Slow sand filters consist

of a layer of fine grain sand supported on a layer of gravel, the topmost layer consisting of a

biofilm (a layer of biological activity called a schmutzdecke), bacteria fungi and a range of

aquatic larvae that have been caught there. As this builds up, micororganisms help to

metabolise organic material in the water, cleaning it. Sand filters require some time to mature,

usually 10-20 days before the filtered water is safe to drink. The water that flows through the

filter during this first time will not be clean enough for human consumption and should be

discarded or put through another filter until a sufficient schmutzdecke has formed. Slow sand

filters require a more or less continuous flow of water to avoid drying out the biolayer and to

ensure a continuous flow of nutrients to support the microorganisms in the biolayer. As the

filter is used, the schmutzdecke will grow bigger and consequently will reduce the flow rate

of the filter. When flow rate becomes too low, the filter has to be cleaned by emptying the

filter and scraping off the top layer of sand.9 Because slow sand filters are slow, the water

needs a long time to get through the sand and capacity is limited, although they are relatively

easy to manage. Below is a diagram showing a slow sand filter.

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Figure 3 shows the working of a slow

sand filter. The tap can be put either at

the bottom or a tube can lead the

treated water up the side of the

container to the top for easier access.

The picture shows the layers of sand.

The biolayer develops above the

layers of fine sand at the top. If one

were to have a the layer of coarse sand

on top, to filter bigger particles first,

which may seem like a good idea, the

biolayer would develop on the finer

sand in the middle of the filter, in fact

making cleaning much more difficult.

Chemical disinfection

In most developed countries the standard process of filtrating water is speeded up with

chemicals, in some instances, with less turbid water, chemicals can be used alone. The most

common chemical used to disinfect water is chlorine (Cl). Chlorine is a very effective

disinfectant and also provides some residual disinfection; it remains in water to stop re-

comtamination. Chlorine is more than 3 times more effective in disinfecting water than the

equivalent concentration of bromine and 6 times more effective than iodine.10

Drawbacks of

using chlorine can be: strange taste and smell of water (usually associated with shock-

chlorination with much higher concentrations), as well as a slight risk of naturally occuring

organic compounds combining with chlorine to form carcinogenic compounds, Disinfection

By-Products (DBPs). However, the WHO states that that health risks associated with DBPs

are much smaller than risks associated with inadequate disinfection.11

Chlorine can be used by

itself, but as it is a naturally volatile gas it is usually used in compounds such as hypo-chloric

acid or chloroamines. Chloroamines may produce slightly lower levels of DBPs, but chlorine

is toxic to fish and aquatic organisms and should be kept out of natural water systems.

Chlorine is only toxic to humans after long exposure and at concentrations much greater than

those used for disinfecting drinking water.

Existing water treatment plants in Zambia use Chlorine to disinfect pipe-water. But it is still

recommended that families chlorinate their water further in case all the bacteria has not been

eliminated at the treatment plant. Even if the water is safe from the plant, bacteria can

multiply very quickly and recontaminate water if the water rests for a long time before

Figure 3: Slow Sand Filter

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reaching the user, or if the pipes conveying it are themselves contaminated. Sometimes the

plants do not use enough chlorine and the residual effect may not be sufficient. Chlorine is a

usable method in urban or peri-urban areas and quite affordable. In Zambia, Chlorine is cheap

because of its extensive usage in household purification of drinking water. One bottle of

Chlorine in the supermarket costs 1500 K, or about 2 kr. A woman in the Kanyama slum of

Lusaka said that 10,000 K (13 kr) bought her enough Chlorine to purify all her water for 10

months.

Sweden no longer uses Chlorine to purify drinking water, because of its volatile nature and

potential health risks, as well as its toxicity to the environment. But in developing countries,

such as Zambia chlorine is a very useful tool to prevent water-borne diseases as alternative

methods do not exist. Chlorine is easy to use and very effective, but because of its toxicity one

may hope it is a temporary solution that can deal with the water-borne diseases that ravage

these countries and will eventually be replaced by more sustainable methods.

Sedimentation

A process in which contaminants that are heavier than water sink to the bottom of a basin and

the water is then led out of the basin above the sediment layer.

Flocculation

Elements such as Aluminium (Al) can be used in a process called flocculation. Flocculation is

a process where colloids come out of suspension in a solute, such as water. Aluminium, which

is positively charged attracts negatively charged bacteria and viruses, all this then sinks to the

bottom (Sedimentation) and can then be filtered out.12

Stabilization

A very popular process for larger scale use in developing countries. Highly contaminated

waste-water is left in ponds where natural biological processes remove pathogens.13

The

ponds are usually built in a series of at least three; anaerobic, facultative and aerobic. The

first, anaerobic pond is 2-5 m deep and water stays there for 1-7 days only. Here anaerobic

bacteria transform organic carbon into methane, removing up to 60 % of biological activity.

Effluent is then led to a facultative pond, 1-2.5 m deep and a detention time of 5-30 days.13

A

combination of processes happen; anaerobic bacteria digest sludge on the bottom and closer to

the surface aerobic processes work, receiving oxygen from natural diffusion, algae

photosynthesis and wind-mixing.13

The facultative pond removes up to a further 75 % of

biological activity. In both these stages, sedimentation occurs and effluent is led to the next

pond from above the bottom sludge. The last, aerobic, pond is often called the finishing,

maturation or polishing pond, because it finishes the work off. Maturation ponds can be built

in series of more ponds for better pathogen removal. Of the three ponds in the stabilization

process, the maturation pond is the one that removes actual pathogens. A shallow pond, only

0.5-1.5 m deep so that sunlight can reach to the bottom for photosynthesis. This pond can

remove a lot of nitrogen and phosphorous from water if used with algaeal photosynthesis and

fish harvesting.13

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Stabilization ponds need a lot of land area and expert personnel to build and monitor the

ponds. They are not suitable for densely populated urban areas because of the bad smell and

large land areas required, but are otherwise popular in developing countries because they use

no electricity or chemicals and can be repaired with locally available materials.13

Figure 4 shows the function of a waste-water stabilization pond with three stages

The three processes of sedimentation, flocculation and stabilization are not used alone but in

combination to produce water safe enough for drinking purposes. Nor should effluent direct

from a stabilizing pond be used for recreation without further treatment, for example

chlorination. These processes are used in larger scale treatment facilities, for example those

used by NWASCO to treat their piped water. (See ”Piped Water in Kiosks” p. 24)

Reverse osmosis

A reverse osmosis filter is based on the chemical process of osmosis. This means that when

two solutions are separated by a semi-permeable membrane, solvent will tend to flow through

the membrane from an area of low concentration to an area with high concentration. The

membrane will let through the solvent but not the bigger particles of the solute, forcing the

solvent to flow instead of the solute in a normal solution. In reverse osmosis, pressure is

applied to the side of the membrane with high concentration; usually 2-17 bars depending on

the concentration of the solution. This forces the solvent (water) from the area of high solute

concentration through the membrane to the area with low (or no) concentration. Eventually all

Figure 4: Waste-water stabilization pond

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of the solute is caught on one side, the reverse of the original osmosis process. Reverse

osmosis is often used in desalination and to remove other dissolved ions.14

Figure 5 shows Reverse Osmosis used to purify salt water; pressure applied on the salt water

forces the water to flow the reverse direction to ordinary osmosis.

Systems and developments

SODIS-Solar Disinfection

Sunlight can be used to disinfect water, the UV

radiation and heat from the sun will kill

bacteria and viruses. This is how it

works: A clean, clear container, usually

a plastic PET bottle because they are

often easily available, is filled with

water. This is left outside for at least 6

hours, up to several days. (Figure 6)

The water is then drinkable. How long

the water should be left depends on the

amount of sunlight available. On a clear

day, 6 hours can be enough, in cloudier

conditions, the water needs to be left for

2 days. The SODIS does not work in

rainy weather. Water that is too turbid

Figure 5: Reverse Osmosis

Figure 6: SODIS bottles on a roof

18

cannot be disinfected using this method, without first filtering it. A simple test to find out

whether the water is clear enough is to stand a filled bottle on a newspaper. If the smaller

headlines can be read when looking through the top of the bottle, the water is clear enough for

UV-disinfection to work. Passing this test corresponds to a turbidity of <30 NTU (Turbidity

units).15

Even this in fact exceeds the WHO recommendation for turbidity of water (See

“What is clean water?” above).

SODIS is a simple, cheap method of purifying water but it has a few drawbacks: (1)

determining how long the water needs to be left in the sun might be difficult as soon as

weather is changeable or a bit cloudy; (2) this method is not good for turbid water without

filtering; (3) water from surface water sources is often very turbid; (4) the water needs to be

drunk quite quickly to avoid recontamination, although this applies in most cases in

developing countries when water storage is difficult. Plastic water containers are otherwise

notorious for growing bacteria. Lastly, (5) water coming out of the SODIS container will be

rather warm, and drinking warm water is not always very enjoyable if resources are not

available to chill water.

LifeStraw

LifeStraw (Figure 7) is a recent invention by the Vestergaard Frandsen Group: shaped like a

straw but a few inches thick, it uses halogenated resin to kill bacteria and virus. Water is

drunk straight through the straw. In tests it could reduce levels of iodine and silver to below

toxicity. However it does not remove heavy metals such as Lead (Pb) or Flouride (F), there is

one version available that can filter Arsenic.16

The LifeStraw is an expensive filter, but may

well save lives in connection with natural disasters where quick, short-term relief is needed.

According to the patent holder: “Halogenated resin compositions are prepared without using

halogen acids by combining at least one silicone intermediate, with an optional silane, an

organic halogen-containing ingredient having functional groups selected from the group

consisting of hydroxy, amine, and carboxyl

groups, and a resin selected from the group

consisting of hydroxy- and epoxy-functional

resins.”17

Larger-scale family versions of the filter are

available for home use.

Figure 7: Child drinking through a LifeStraw

19

Nano-filter

Researchers at Stanford

University have

developed a

Nanofilter (Figure 8)

that kills bacteria with

an electric field. Their

filter is ordinary

cotton fabric, coated

with highly

conductive carbon

nanotubes and silver

nanowires, silver has

long been known to

have chemical

bacteria-killing

properties. The coated

cotton is layered to

about 2.5 inches thick. The pores of this filter are much larger than conventional filters,

allowing water to flow through up to 80,000 times faster. Electricity passing through the filter

kills the bacteria as they pass through the filter. Electrons pass very smoothly over the filter

thanks to the very small size of the nanoparticles, thus only a current of a few milliamperes is

needed. The silver helps prevent biofouling; buildup of bacterias caught in a filter, because

any bacteria that lag behind will likely be killed by the silver nanowires. In tests, 98% of E.

coli bacteria were killed when subjected to 20 Volts of electricity during several seconds in

the filter. The team are currently testing the filter on different bacteria and using multiple

filters to kill more bacteria. They are hoping the filter might be useful in developing countries

because it is cheap; so little silver was used for the nanowires that the cost was negligible. The

basis of cotton is easily accessible, but the nanomaterials will still be a difficult issue in

developing countries.18

Still, killing bacteria with an electric current is an interesting idea, in that it will be much

faster than conventional methods of filtering and disinfection with UV-light, if materials are

accessible and little electricity is needed.

Ceramic water filter

Potters for Peace are an organization in America that have been working actively with local

organizations in developing countries since 1998, making ceramic water filters. They work all

over the world, but mainly in Central and South America, where they started. They never sell

filters themselves, but only travel to a location to train local potters to make the filters and sell

them to communities. The PFP filter (Figure 9) is a simple bucket 11” wide, 10” deep made

of local terracotta clay, mixed with a combustible fibre, such as sawdust or old rice-husks and

coated with colloidal silver, known for it’s anti-microbial properties.19

Figure 8: Nanofilter SEM 2000x

20

It is made by pressing the clay mixture in a mold of

aluminium and then firing at 860° C, the simplest such press

can be a hand-operated hydraulic truck jack. This

bucket is kept in a plastic or ceramic receptacle with a

tap at the bottom and a lid. A filter rate of 1.5-2.5

litres/hour can be expected, depending on the

clay/fibre mixture and firing temperature. A bucket

can be expected to last about 40 months before having

to be replaced. A complete filter costs around 15-25

US$, a replacement filter bucket around 4-6 US$.

Field experience and clinical test results have shown

that this filter removes 99.88% of most water-borne

disease agents.20

Colloidal silver is a solution of silver cations

(negatively charged ions) in water. For use in filters,

protein, such as xanthium gum, is added to keep the highly concentrated silver cations from

separating from the water. Colloidal silver can kill bacteria by inactivating their metabolic

enzymes, or attaching to the cellular membrane, causing the cell to grow too much and die.19

The Potters for Peace filters seem an excellent method for cleaning water in developing

countries, depending, of course on whether it is suitable for a community’s resources and

needs. It not only seems to be easy to look after, cheap

and easy to make but can also provide an extra

economic upswing for the potters that make them.

Bio-sand filter

The Biosand filter (Figure 10) is an adaptation of the

slow sand filter, as described above. (See “Filtration”)

It has been proven to be just as effective as slow sand

filters though laboratory and field tests. It is smaller

than a traditional slow sand filter and according its

developer, more adapted to intermittent use, making it

suitable for small-scale family use. It can be contained

in concrete, plastic or another waterproof, rustproof and

non-toxic material. Typically a cylindrical shape about

0.9 m tall and 0.3 m in diameter, the sand and gravel

layered inside. Treated water collects at the base and is

propelled by its own pressure to a spout at the top of the

filter. The filter has a diffuser - a perforated plate above

the sand layer to dissipate the initial force of the water

poured into the filter and let it flow evenly through the

biolayer. A lid completes the system. 21

Figure 10: Bio-sand filter

Figure 9: Ceramic water filter

A bio-sand filter with sand, a lid and diffuser

plate and pipe which leads up to the top for

easy acess

21

Correct manufacturing and installation, to ensure a long and succesful life, of the biosand

filter requires:

▪ that the box that doesn’t leak

▪ screened and washed sand, (organic free, Uniformity Coefficient of 1.5 – 3.0 and an

Effective size of 0.15 – 0.30 mm - a sieve analysis is required to determine these

numbers)

▪ well washed under-drain and separating gravel

▪ diffuser plate and lid

▪ safe storage container

▪ maximum standing water level of 5 cms

▪ start-up (maturing) time of 14-21 days

Free designs are available from the Centre for Affordable Water and Sanitation Technology

(CAWST).21

The capital cost of installing a bio-sandfilter is 12-30 US dollars, depending on the choice of

container, a concrete container lasts longer, though it is heavy should one want to move it.

This does not include transportation costs or education costs. Current installed bio-sandfilters

are still performing well after 10 years or more; the expected life span is 30+ years. There are

no costs for maintaining the filter, although lids and diffusers may need to be replaced, but not

often.21

Water quality tests carried out in 2005 on 107 long term bio-sand filters used in Haiti showed

a 98.5% reduction in E-coli bacteria, the indicative for pathogenic bacteria presence

recommended by the WHO. In lab tests, a 70->99% reduction in bacteria was measured.

Turbidity was reduced by 95% (to <1 NTU, below the WHO recommendation5) in lab tests

and 85% in field tests.21

Such water is not perfect, but it is a great improvement and

considerably reduces the risk of disease. Bio-sand filters are, like other all other filters, not

very good for removing dissovled chemicals or minerals. To remove those, further treatment,

such as flocculation is required.

Bio-sand filters are reasonably simple units and suitable size for a family and because of the

lid is suitable for more intermittent use without the schmutzdecke drying out. Especially the

concrete container is solid and lasts well. Water poured into it comes out drinkable quite

quickly and the quality of the water is reliable as long as the filter is cared for properly, this

requires some simple training. A constant supply of clean water can be guaranteed if a village

or community share several filters at different stages, so that if one needs cleaning and

maturing again, another filter covers for those 20 days.

Kanchan Arsenic filter

The arsenic filter works just the same as the biosand-filter, but a layer of ungalvanized nails is

added on the diffuser plate to filter out arsenic, a carcinogen. The nails filter arsenic by the

principle of iron hydroxide adsorption; arsenate ions in water are quickly attracted by the iron

22

oxide on the rusty nails and form bigger particles. These particles then dislodge and are

filtered out by the sand-filter.22

Field tests of the Kanchan Arsenic filter show 90-99%

reduction of iron in the water and 85-95% reduction of Arsenic22

apart from the above results

for an ordinary bio-sand filter. The Arsenic filter is also better than the ordinary bio-sand filter

for reducing high levels of iron; the Bio-sand filter is not suitable for removing iron.

Water in Zambia

Zambia is a landlocked country in the middle of Sub-Saharan Africa. It covers an area of

752,618 sq km, slightly larger than the US state of Texas. 9,220 sq km of these are water in

rivers; such as the Zambezi and lakes; such as Lake Kariba and Tanganyika. If one wanted to

one could travel up to 2,250 km on Zambia’s waterways.23

The most common problem with

water resources is not scarcity, there is enough water in Zambia to feed the whole of Africa,

but pollution. Zambia has potential access to 105.2 cu km of renewable water resources,

whereas only about 1.74 cu km are withdrawn every year. This is about 149 cu m per capita.

Of this, 76 % is used by agriculture for irrigation and watering livestock; this does not include

crops that grow with rainwater only. 17 % is used in the domestic sector, in homes or for

limited scale agricultural or industrial use. Only 7 % is used in industry.23

These figures

pertain only to water withdrawn from public access piped water systems, the great majority of

Zambia’s rural population have no such piped water access and nearly 30 % of urban dwellers

still have to get water from other sources, small wells or surface water.

The small portion of water withdrawal for industrial use (7 %) is stark evidence of the limited

development of Zambia’s industry, and possibly the potential of Zambia as a developing

nation, because industry plays an important part in the development of a nation. Industry

commonly uses vast water resources, especially secondary economic sector industries; those

involved in making raw materials into products, e.g computer parts or packaging of

vegetables. In the production of silicone wafers for computer chips, 2,275 gallons or about 8.6

cu m of water may be used to produce a single silicone wafer.24

Developed countries

consistently show a much greater proportion of water resources used for industry; the US use

about 46 % of the total withdrawal, Sweden 54 % and the UK use as much as 75 % of their

total withdrawal in the industrial sector.23

Available water sources

Potential natural sources

Groundwater

Groundwater is accumulated water underground, sometimes very, very old, that seeps through

the ground from rainfall above. Groundwater is either still or constantly in slow motion,

driven by gravity and continuously dispersed and filling microscopic pores in the subsoil and

23

underlying rock. Where groundwater may accumulate and at what depths is determined by the

composition of soil and bedrock. Some, called aquifers, readily conduct groundwater. Others,

aquifuges, do not.6 Groundwater can be accessed by digging wells; natural places where

groundwater emerges at the surface are called springs. Groundwater is often very clean,

because it has been naturally filtered through soil and bedrock and continually available as

long as water is not removed faster than the rate at which nature can replenish it. Very old

groundwater is called fossil water, water trapped in rock far beneath the surface that

accumulated a long time ago under different climatic and geological conditions than those we

have today. Such water is often heavily mineralized, full of dissolved minerals such as salt.

Another drawback of fossil water is that it is not so readily replenished by rain. Karst springs

are sometimes formed where rock is chemically soluble in water, for example limestone.

Soluble rock is dissolved, whilst the impermeable surrounding rock is not. This is the same

process that creates caves. Groundwater from Karst springs is used, but a disadvantage is that

they are susceptible to pollution, because groundwater has accumulated in large voids rather

than filtering through rock.6 In Zambia, the water table is very high, making it very easy to

dig wells and reach clean ground-water. Hand-dug wells are common in rural communities,

but these wells are often left uncovered, leading to contamination.

Surface water

When improved water sources are not available, most people in Zambia take their water from

local surface water sources - a river or lake, or as these are few and far between, usually the

local Dambo. (Pers. Comm. Village Water 2011) A Dambo is a shallow grass-covered

depression in the ground or a small valley that is seasonally or permamently waterlogged.

They support no bushes or trees but are rich in various specie of grass, herbs and flowering

plants and often surrounded lush grass and smaller shrubs, excellent grazing for wildlife. In

higher land, amongst hills, Dambos are sometimes the sources of streams or rivers-

groundwater springs.25

All surface water is easily contaminated by animal and human waste

and is not suitable drinking water sources, but people often have no choice.

Other surface water sources are Pans, although these are strictly seasonal and dry up soon

after the end of the rainy season. Pans are also shallow pools, but usually do not support rich

vegetation.25

Flood-plains are low-lying grasslands on the edges of rivers, streams and lakes, seasonally

inundated with floods. They contain no trees or bushes, only a carpet of grass that can tolerate

being submerged for part of the year. The largest areas of floodplains in Zambia are beside the

Kafue river in central Zambia and around the Zambezi river in south-western Zambia.25

24

Piped water in kiosks

In the slums of urban areas, shallow, uncovered wells, such as the one in Figure 11 are

common and people still use them for water, despite that they have long since been

contaminated by waste, but piped water does exist in urban areas.

Some houses have piped

water provided, but in the

poorest areas in urban settlements;

slums, water kiosks (Figure 12)

provide the only source of safe

water. NWASCO (National Water

Supply and Sanitation Council) in

Zambia is the regulatory body that

oversees the provision of water

through piped systems. According to

their latest figures, about 74 % of

Zambia’s urban and peri-urban

population are covered by piped

water systems, including

population of the country as a

whole, this figure drops to about 64

%.26

Piped water systems are

provided through 11 CUs

(Commercial Utilities) and some

private providers. These private

providers are different companies that provide water and sanitation facilities as fringe benefits

to their employees. NWASCO do not provide water on their own, they oversee and regulate

the operation of these water providers, and all water providers must obtain a license from

NWASCO. Commercial utilities are public institutions that provide water and sanitation

facilities to people in their catchment area. Water is much greater than sanitation provision.

For example: Lusaka WSC (Water and Sanitation Commission) are estimated to cover about

70% of of the population of Lusaka province whereas sanitation coverage is only 19%.26

Water kiosks are run by private vendors appointed and regulated by NWASCO, through the

WSCs, where people can fetch water and pay a tariff rate to fill a container of 20 litres. These

kiosks are open between 4 am and 7 pm every day, but queues are commonly very long and

you are only allowed to fill one container at a time. You are lucky if you have time to fetch all

the water you need.

Figure 11: Shallow well in the Kanyama slum compound of

Lusaka

25

The tariffs for all water utilities in Zambia are set according to categories of housing;

classified as low-cost, medium-cost or high-cost.27

How much you pay depends on what

category you belong to. The rates in the different WSCs depend on the running costs of the

individual WSCs, but in Lusaka WSC a 20 litre container of water costs around 50 K (around

6 Swedish öre). Some kiosks also run as community led schemes, sometimes charging as

much as 100-150 K for a 20-litre container. (Pers. Comm: Hara Kasenga 2011) This may

seem very cheap, but the best way of evaluating these figures is by looking at the estimated

proportion of the total household income that is spent on water. Below is a table compiled by

the International Poverty Centre, it estimates the share of household income that Extremely

poor and Moderately poor households spend on water. Figures are for urban centres in the

provinces below.

Table 2: Monthly Share of Mean Household Income spent on Low-cost water 2002-

2003(%)27

Tariffs are considered unaffordable if more than about 3% of household income is spent on

water. According to these figures (Table 2), the low-cost water tariffs are unaffordable in all

Lusaka Mulonga Western Southern Nkana Chipata

Extremely poor 7.4 7.9 9.0 3.5 5.3 14.0

Moderately poor 5.2 5.6 6.3 2.5 3.7 9.9

Figure 12: Water kiosk in the Kanyama slum compound of Lusaka

26

provinces except Southern, the most expensive is found in Chipata. Water from commercial

utilities is considered unaffordable for 60% of Zambia’s population since recent estimates

suggest that 68% of Zambia’s population live in poverty.27

Despite these figures, it has been difficult for established Commercial Utilities to recover their

costs from tariffs collected, according to Dagdeviren and Robertson. This means that costs to

run these Commercial Utilities are not covered by revenue. The main reason for this is the

high level of Unaccounted for Water (UFW, Figure 13), water that is provided but not

charged for. In 2008 the average UFW was 45%.26

This is due to a lack of maintenance and

poor infrastructure. Causes include leaks appearing in badly maintained pipes, vandalism or

unauthorized connections to the pipe system. A lack of metering (measuring the amount of

water provided) can also be a factor. According to NWASCO (2008), the estimated revenue

loss due to UFW was 201 billion K in 2007/8.26

This is about 272 million Swedish Kronor or

43 million US dollars. This difficulty in recovering revenue greatly lowers incentive to

expand water services in the poorest slums of Zambia and there is little capacity for

investment in improvement or expansion without aid from government subsidies or donor aid.

According to Dagdeviren and Robertson, the Zambian government only invested between 2-

12% of their planned capital spending on water supply and sanitation between 1998-2002.27

The quality of water supplied is monitored by NWASCO and all water provided is first

treated to remove pathogens, utilizing methods such as sedimentation, stabilization, filtaration

and chlorination. (Pers. Comm: Hara Kasenga 2011) (See “water purification” above)

In their investigation into the commercialisation of the water supply in Zambia, Dagdeviren

and Robertson (2008) found that overall, the system of commercialisation does suffer from

some inherent design flaws, not uncommon when commercializing an essential public service

Figure 13: UFW; a rusty, leaking water container

27

in low-income countries where poverty is common and other social welfare systems are

absent. Goals of economic efficiency on the one hand and social policy on the other often

conflict and significant levels of investment are needed to try to reconcile these two aims and

fund a reliable system of water supply and sanitation, especially to expand networks to the

poorest people that can otherwise be excluded due to the low financial incentive.27

Many of

the existing systems were put in place many years ago but have not been improved or

extended to accomondate an exploding population in urban areas. A system that may have

been installed to serve 1000 households may now have to cater for 5000.

A long-term sustainable solution is beyond the world of commercialized WSS systems,

utilities and regulators, because it involves concerted involvement from various government

departments, including housing, urban planning, infrastructure development etc. That is in the

future, beyond MDGs that measure access to safe water and sanitation, but not the quality of

that access.

Public water kiosks can provide a short-term solution, in that they provide much needed

drinkable water, but as seen above, they can be comparatively expensive. Most people can

afford 50 K for a container of water, but, according to a teacher at Chinika high school in

Lusaka, there are those who still cannot afford it, usually if they are in debt. The water kiosks

serve a purpose, but they are not ideal as service may be unreliable, for example if electricity

fails and an electric pump cannot function, and they do not cover everybody-only 74% of the

urban population and 64% nationwide. (Pers. Comm: Hara Kasenga 2011)

The impact of inadequate water and sanitation

A 2006 United Nations report states that “there is enough water for everyone.” the problem

often lies in mismanagement, sometimes corruption and a lack of investment in human

capacity and physical infrastructure. Developed countries have a piped water system that

serves taps in every household. In developing countries this is often inadequate or non-

existent. Here people must turn to natural sources of water, lakes, streams etc that are not

always clean. WHO stated in March 2010 that 5.9 billion people worldwide are using water

from safer, improved sources, that is 87% of the world’s population. 84% of the population in

developing countries are using safer water. Sub-Saharan Africa and Oceania are lagging

behind; 60% of people in Sub-Saharan Africa and 50% in Oceania are using safer water. 2.6

billion people still do not have improved sanitation. In most of Africa, less than 50% of the

population have improved sanitation, in Oceania this figure is slightly higher, 50-75%.28

This

still leaves many millions of people world-wide without clean water and adequate sanitation

due to lack of infrastructure and lack of knowledge, especially amongst the population.

According to the CIA World Factbook, the most common infectous diseases are in fact water-

related. They are water-borne diarrhoeal diseases such as Cholera (See “Water related

diseases”) and Hepatitis A, which affects the liver. Schistosomiasis is also common, a water-

based parasitic disease. The risk of infection is deemed very high.23

28

Zambia’s Human Development Index (HDI) is 0.3809, compared to 0.8989 in the US, 0.8941

in Sweden and 0.8472 in the UK (Gapminder). Out of every 1000 births in Zambia, 20

children die due to diarrhoeal diseases before the age of 5.29

According to a WHO report from 2004, in World Bank regions; about 922,000 deaths could

be attributed to unsafe water or sanitation in sub-saharan Africa. In high-income countries, the

same figure was 7000.30

Below (Table 3) is a table illustrating the impact of unsafe water and sanitation, with

comparisons to other well known health risks.

DALYs (Disability Adjusted Life Years) is the count of how many potential, total years of

life are lost in the population of a region due to different causes.31

PAF (Population

Attributable Fractions) is the contribution by a certain risk factor to disease and death in a

population or the proportional reduction in disease or death if exposure to a risk factor were

reduced to a ideal scenario, e.g if everybody had safe water and sanitation or nobody used

tobacco.30

Unsafe water and sanitation affects children and older people the most, because their immune

systems are weak. Especially children can put themselves at risk in the household because

they do not know what water is safe. A thirsty child will drink any water in the house. It does

not know which water is safe to drink and what is being used for washing dishes or personal

hygiene. Of the 29,600,000 DALYs attributed to unsafe water and sanitation in sub-saharan

Africa (Table 3), 24,600,000 belonged to a group under the age of 4. Most years are lost if a

child dies, and children are most at risk. 7.9% PAF is a large portion of all deaths, in the same

report by the WHO, only two other factors contributed to more deaths: Unsafe sex at 15.2%

and Underweight (only in children below the age of 4), 8.8%.

Scale: DALYs: PAF for

mortality:

Cause: Unsafe

water,

sanitation

Tobacco

use

Alcohol

use

Unsafe

water,

sanitation

Tobacco

use

Alcohol

use

SSA 29,600,000 1,903,000 7,704,000 7.9% 1.2% 2.3%

High-

income

countries

226,000 13,051,000 8,050,000 0.1% 18.1% 1.6%

Table 3: DALYs and PAF for mortality attributed to selected risk factors,

comparison of high-income countries and Sub-Saharan Africa

29

As is quite clear from the figures above, the impact that unsafe water and sanitation has on the

health of a population is great. It is one of the easier problems to remedy and a major

difference can be seen very soon after improvements have been made in a community. Water-

borne diseases are almost eliminated and the burden on local healthcare due to such diseases

is greatly reduced. (Pers. Comm: Village Water 2011)

Conclusion

There is no one single, perfect solution to providing clean water. Even in Zambia several

potential systems may be used. Because the water table is quite high in Zambia, many local

charities opt to dig wells and install pumps and utilize ground water. Ground water is still safe

in Zambia and wells can provide a lot of water quickly when cared for properly and not over-

used. The risk of ground water drying out is so far extremely slim in Zambia.

Installing a water purifier or a well always requires outside help. This comes from charities

that help to install the system and, most importantly, educate people on the importance of

clean water and sanitation and teach them how to maintain their filter or well in working

order.

For purifying water on a smaller scale setting in Zambia a filter such as the bio-sand filter or

ceramic pot filter is suitable, they are cheap and simple and able to clean out the elements that

are a problem in Zambia - bacteria and viruses. Traditional slow sand filters are often used on

a much larger scale, in water treatment plants as they are or with help from chemicals. SODIS

disinfection cannot be used without a filter, as surface water is often turbid and disinfection

time depends a lot on the weather and is difficult because of that. The LifeStraw is rather

expensive and cannot be acquired by local people on their own, it is handed out by charities

and the same problem still remains when the LifeStraw reaches its use-by date. The nano-

filter needs a lot of further research, but it sounds as if it might be expensive and difficult to

mend or find replacement parts Moreover, electricity is often a problem in Zambia.

Stabilization and chlorination are used by NWASCO now. In urban and peri-urban areas,

Chlorine is a cheap, accessible method for ensuring safe drinking water. It is a relatively

short-term solution as it is not environmentally sustainable and one may hope that safer

chemicals will soon be available also in developing countries. Chlorine is not an option in

rural areas, these small communities are self-sustaining dependent on agriculture, far away

from any supermarket that sells Chlorine. In these communities, sand-filters or wells are so

far the only option for safe water.

The ceramic pot filter and the bio-sandfilter do not differ noticeably in cost. They both cost

around 20 dollars to install, the bio-sand filter can cost a little more to install, but it does not

require regular replacement like the pot in the ceramic pot filter. The ceramic pot is also

breakable and replacement requires that the local potters that have been trained remain

available and also that the additional colloidal silver and xanthium gum are available. The

bio-sandfilter is sturdy and has been proven to last for a long time without replacement. It is

very easy to maintain and clean, replacement parts are locally available if need be. Neither

30

pose threats to the environment as the do not contain any chemicals that might leach (in the

ceramic filter, the colloidal silver is firmly attached to the filter with xanthium gum). Used

filters can be disposed of, plastic parts and concrete parts however cannot be dumped

anywhere. The small amount of colloidal silver in the ceramic filter is unlikely to pose any

risks to the environment. Sand from an old sandfilter can be disposed anywhere, it is a natural

product.

These filters are also very good because the education provided by charities that help in

installing them makes a great difference and empowers people to change their lives by

themselves. When a community builds their own purifier or well and maintains it collectively

as well as improving general sanitation habits, it is the most sustainable. The installation of a

bio-sand filter does this, it is the cheapest and easiest to maintain and has a long life span,

giving it the edge on the ceramic pot filter. The bio-sand filter can be built by any charity, as

drawings are freely available from CAWST, whereas the ceramic pot filter is so far tied to the

Potters for Peace charity.

31

Sources

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svar/Dricksvatten/Vilka-salter-mineraler-ska-ett-kallvatten-eller-naturligt-

mineralvatten-innehalla-for-att-vara-bra/ (swedish) retrieved 15/10-2010

2. Sodium, EveryNutrient www.everynutrient.com/sodium.html retrieved 15/10-2010

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2010

4. Bottled Water Sold as Natural Mineral Water Codex Alimentarius,

http://www.codexalimentarius.net/web/index_en.jsp retrieved 15/10-2010

5. Turbidity Lenntech water treatment and purification Holdings B.V

http://www.lenntech.com/turbidity.htm retrieved 3/3-2011

6. The Battle for Water-Earth’s most precious resource Understanding Global Issues

(No further information available)

7. Water and Health-Cholera’s grim warning Understanding Global Issues (no

7/1992)

8. The 7 pandemic’s of Cholera (2010) CBCNews-Health 22 October 2010

http://www.cbc.ca/news/health/story/2008/05/09/f-cholera-outbreaks.html

retrieved 4/3-2011

9. Slow Sand Filter Akvopedia Akvo.org

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15. SODIS method-How does it work? SODIS

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16. Greenemeier L (2008), Water filtration system in a straw Scientific American 25

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Personal Communications

Village Water Zambia, (Contact address:) Village Water, Unit 20a Business

Development Centre, Stafford Park 4 Telford Shropshire TF3 3BA United

Kingdom, 0044 (0)1952 850441, ellie@villagewater.org

Hara Kasenga, NWASCO, Plot 164 Mulombwa Close Off Bwinjimfumu

Road, Fairview, Lusaka Zambia 10101, 00260 211 226941/2,

khara@nwasco.org.zm

33

Tables and Figures

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http://www.codexalimentarius.net/web/standard_list.do?lang=en retrieved 28/10-2010

Table 2: Monthly Share of Mean Household Income spent on Low-cost water,

Dagdeviren H & S A Robertson Reforming without resourcing: The case of the urban

water supply in Zambia International Poverty Centre, Policy research brief (no 8, sep

2008)

Figure 1: Sacchi disk, Turbidity Lenntech water treatment and purification Holdings

B.V http://www.lenntech.com/turbidity.htm retrieved 3/3-2011

Figure 2: Water goes global, New Scientist, Environment (18 dec 2008)

http://environment.newscientist.com/data/images/archive/2670/26700101.jpg retrieved 28/10-2010

Figure 3: Slow Sand Filter, Astatke A, Bunning S and F Andersson (1986) Building

ponds with animal power in the Ethiopian highlands Appendix VI, International

Livestock Centre for Africa, Addis Ababa, Ethiopia

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2011

Figure 4: Waste-water stabilization ponds Akvopedia Akvo.org

http://www.akvo.org/wiki/index.php/Portal:Sanitation retrieved 6/3-2011

Figure 5: Reverse Osmosis, ORACLE ThinkQuest

http://library.thinkquest.org/C0131200/Osmosis.htm retrieved 11/11-2010

Figure 6: SODIS bottles on a roof, SODIS http://www.sodis.ch/index_EN retrieved

3/3-2011

Figure 7: LifeStraw Greenemeier L (2008), Water filtration system in a straw

Scientific American 25 February 2008, Nature America Inc, New York NY

http://www.scientificamerican.com/article.cfm?id=water-filtration-system retrieved

15/10-2010

Figure 8: Nanofilter 2000x, Bergeron. L, Filter uses electrified nanostructures to kill

bacteria Stanford Report 31 August 2010

http://news.stanford.edu/news/2010/august/nano-pure-water-083110.html retrieved

15/10-2010

Figure 9: Ceramic water filter, filters Potters For Peace

http://s189535770.onlinehome.us/pottersforpeace/?page_id=9 retrieved 3/3-2011

Figure 10: Bio-sand filter, Concrete Bio-sand filter Akvopedia Akvo.org

http://www.akvo.org/wiki/index.php/Concrete_Biosand_Filter retrieved 11/11-2010

Figure 11: Shallow well in the Kanyama slum compound of Lusaka, Private picture,

Zambia March 2011

Figure 12:Water kiosk in the Kanyama slum of Lusaka, Private photograph, Zambia

March 2011

Figure 13: UFW; a rusty, leaking water container, Private photograph, Zambia March

2011

34

Bibliography

Stock R (2004) Africa south of the Sahara-A geographical interpretation”, Second

Edition, Guilford Press, New York NY

Appendix

Notes From the Interview with Village Water Zambia 25

March 2011

Village Water Zambia (VW) is an NGO that works in the water and sanitation sector. They

are a Zambia-registered charity since 2007 with its head office in Lusaka and two field offices

in Mongu and Kaoma in the Western Province. The fund-raising comes from the headquarters

in the UK where they are also a registered charity under the name of Village Water UK. VW

install wells to access groundwater or rehabilitate existing ones, as well as install pit latrines.

In terms of the number of people covered, VW could be called one of the biggest NGOs

currently active within the water sector in Zambia, of which there are less than 20. Most of

their funding comes from the UK and the Netherlands and help from US is a possibility. Other

funding partners include UNICEF, the African Development Bank, the World Bank and the

Danish and Irish governments. The Zambian government often loan money to support the

building of infrastructure, but often only half of the loaned money goes to what it was meant

for. Generally very little aid money is invested in the water and sanitation sector, the Swedish

government for example, do not provide aid in this sector at all.

VW helps around 90 villages per year, each with a minimum of 250 inhabitants. A descision

by the government dictates that every water point installed must serve at least 250 people-so

one may ask what happens to the villages with less than 250 inhabitants? Villages approach

them themselves and ask for help and with some help from the local government, VW can

decide which villages are in the greatest need and would benefit the most from their help. The

idea is to get people together, get a community to cooperate over maintaining a new well.

They educate people about basic sanitation and its importance for improved health and thus

fuel a desire in people to actively help their situation. They help the villagers analyse their

situation and the villagers can then draw on local knowledge and resources to construct their

own sanitation facilities from locally available materials. The villagers, with the help of VW,

set up their sanitation facilities better, i.e hand washing facilities, bath shelters, refuse pits,

dish stands and pestle and mortar stands to avoid contamination. The villagers are also

supported in digging their own pit latrine and constructing huts to cover them. So far, VW

have been digging wells by hand, since the watertable in the Western province is quite high

and costs are much lower, but this is rather slow work and they are looking into a new

method, mechanical methods called jetting and rota-sludging. Hopefully these will be in use

within the year, they will then be able to dig 2-3 wells per day, compared to one hand-dug.

The new water point also has to be managed after VW have left; VW train two people from

each village, a man and a woman, who can look after the well and mend the pump if it breaks.

35

Since these projects are 100% funded the vllagers do not have to pay anything themselves,

VW also leave some money behind which can be used to buy replacement parts for the pump.

VW help rural schools as well and they have applied for money from UNICEF to support this.

These schools usually have wells, but they are not covered and easily susceptible to

contamination by anything from bacteria to a dead dog. In these cases VW can merely

disinfect the well, seal it and it will be safe to use. They also build pit-latrines, as these

schools often lack these facilities. VW are currently in discussions with Oxfam, a large

charity organization in Britain, to extend their work to urban areas in Lusaka.

One of the difficulties faced by NGOs is coordination; VW have all their installed waterpoints

and latrines as dots on a map, but the best thing would be if all projects of all NGOs working

in that area could be on the map, and will al those dots still be there in 2030? (MDG: 100%

access to improved sanitation by 2030). There is an agreement with the government – each

NGO has a limited number of wells they are allowed to install per district. What happens is

that one village will be helped, another will not. With NGOs cooperating - with all their dots

on the same map they will be able to make sure all villages are helped.

On the question on the quality of the groundwater: That depends on where you are in Zambia,

in Kanyama, Lusaka for example, you have kiosks that provide water but there is no such

thing in Western Province. Bacteria and viruses are not much of a risk in the groundwater of

Western Province, unless it has been contaminated by a nearby toilet or if bacteria and viruses

contaminate an open well. Pit latrines should be built downstream from the well to avoid the

risk of contamination. Too high concentrations of minerals, for example copper, can be a

problem, but there are few filters that can adequately deal with mineral concentrations. VW

test each new well, and if they find that the mineral concentration of the water is too high,

they simply destroy that well and build another one elsewhere in the vicinity. In one case that

had to do this shift four times.

Pit latrines: In urban areas, the latrines are often emptied regularly with a sewerage truck, but

there is still a risk of overflowing in the rainy season. In rural areas pit latrines are not

emptied, it is common that the latrines of rural schools overflow during the rainy season. VW

simply recommend that villagers cover a full latrine and build a new one, plant a tree over the

old one or something. Dry toilets are recommended – where faeces and urine are separated,

urine can then be diluted and used as fertilizer because of it nitrate content. VW hope to be

able to introduce a new pit latrine, especially in schools where overflowing latrines are

commonplace. The Ecosan latrine is built above ground, with two pits. It is a dry toilet, thus

when one pit is full, the other is used. The full pit decomposes naturally, leaving a small

amount that can easily be dug out and used as fertilizer for a garden.