FACULTY OF CIVIL AND WATER RESOURSES ENGINEERING

WR 498 FINAL PROJECT YEAR 1(FPY1)

NAME: MTALO, Theresia F.

REG NUMBER: 2011- 04- 02721

DEPARMENT: WRE

ABSTRACT

Kiwalani ward is the among the Ilala district in Dar es Salaam

city. The ward is characterized by urban and physical

development, informal settlement with high population

concentration which is unplanned settlement of low income

household.

Water shortage has been problem to this area which made many of

people to depend on ground water for consumption. But due to poor

living condition ground water quality has been altered to the

extent that ground water has loss its potential uses to human

being. Therefore from this study will concentrate mainly on

assessing the quality and proposing better method to treat the

ground water.

ACKNOWLEDGEMENT

PROJECT PROPOSAL

PROJECT TITTLE

Assessment of underground water quality at Kiwalani area Dar es

Salaam

BACKGROUNG

Groundwater is an extremely important domestic water resource in

much of the country, and one of the more dependable resources for

human development activities. In semi-arid and the drier parts of

the country groundwater has played and will continue to play a

major role as the sole water source for various uses especially

in the central and northern parts of the country and the drier

regions of Dodoma, Singida, Shinyanga, Tabora, Mwanza, Mara,

Arusha, Coast and Southern Kilimanjaro.

Groundwater as a source of water has some advantages above other

water resources. It is mostly hygienically safe, and it does

generally not contain pathogenic germs.

Dar es Salaam is the big city that with large population,

settlements, and different activities. Distribution of settlement

is an evenly proportional; some of areas are much populated

compare to other areas. This situation becomes hard in provision

of social services like water supply, power and other services.

PROBLEM STATEMENT

Water problems base in quantity and quality at Kiwalani area in

Dar es Salaam region has been an endless issues. Regardless the

Ministry of water resources and other institutions of water work

hard to ensure at least each part of this region obtain water for

domestic uses.

There are many sources for water supply in Dar es Salaam such as

rivers (Ruvu River), shallow wells, boreholes, springs and

rainwater harvesting. Quantity and quality depend on the sources

and methods for water treatment before use.

Most of the southern parts of Dar es Salaam experience water

shortage and poor quality of water that is used for domestic

water or industrial purpose. This is because most of these areas

are not connected to the city water supply network of Ruvu

transmission (only 40% of consumers are in the system of DAWASCO

water) and poor quality of water from the sources that are mostly

used by people living in those areas. The common water sources

used water supply in these areas is water from ground water

(shallow wells and boreholes).

Water problems in term of quality lead to eruption of water borne

diseases like cholera and dysentery. This is due to water

pollution such as poor location of the wells from the location of

pit latrine, poor waste disposal that pollute the ground water

i.e. from industries, toxic chemical are buried into the ground

and dissolve rocks and soil minerals. When water has been

polluted even if the water quantity is of high amount that water

will have no meaning to the consumers.

Objectives

General objective

Assessment of ground water quality

Specific objectives

To assess source of water to Kiwalani inhabitant

To assess different water treatment methods that are

commonly used by people at Kiwalani.

To determine the best method and cheap that can be used to

treat ground water at Kiwalani area.

SCOPE

The study is based on finding out

Why ground water quality at Kiwalani get polluted mostly

during rainy season that leads to water borne diseases to

people living in this area.

Methods to be used to improve the ground water quality

(best and cheap method for water treatment).

Methodology

Literature review (reference from water supply manual,

lecture notes (WR423, 230), and internet website).

Water quality

Ground water origin and occurrence

Ground water pollution

Ground water treatment methods

Visiting the study area: - locate the areas of the ground

water sources (wells by GPS) .

-To identify the

location of sewerage systems and waste disposal

Areas

Questionnaire (Oral method)

based on the quality of the water,

water uses

problems associated to ground water,

methods used for treatment)

Collection of water samples for testing and analysis in

water laboratory

Water sample from the boreholes and shallow

wells

Test water sample before treated (as baseline

condition.)

Test water sample after being treated

Test results and evaluation of results.

Quality of the water (water parameters)

Best method to be use in treatment of ground

water

General report of project.

BUDGET

No Item Units Quality Rate Amount

(Tsh)1 Stationeries NA 800002 Transport NA 5 3200 15000

cost3 Internet

access

NA 1000 10000

4 Others NA 350005 Water

analysis

NA 6 100000

Tot

al

240000

WORK PLAN (second part)

Activities 1 2 3 4 5 6 7 8 9

1

0

1

1

1

2 13 14

1

5

1

6

1

7

Literature review                                  

Assess water sources

at Kiwalani                                  

Assess geological

formation                                  

Location of wells                                  

Sampling                                  

Result and

recommendation                                  

Presentations                                  

Report compilation                                  

Submission of report                                  

DISCRIPTION OF CASE STUDY AREA

The case area for the above stated problem is at KIWALANI ward in

ILALA district.

Population and settlements

KIWALANI is an administration ward in the ILALA district of the

Dar es Salaam region of Tanzania. According to the 2012 census

the ward has a total population

Information RecordsTotal number of people 82,292Male 40,237Female 42,045Average household size 3.7Sex ratio 96

Reference: 2012 population and housing census general report.

Government of Tanzania retrieved 2013/08/21

Settlement is characterized by unplanned settlements which are

prone to flash flooding.

Topography and Landforms

Kiwalani is one of Ilala ward located at lower land which is

also found along flood plain of Msimbazi River. During rainy

season people live in this area are much affected with flood

which results to health hazardous and environmental

pollutions.

Climate

Temperature at this area varies from 260C in August to 350C

in December and January each year.

Rainy season range from March to May, average monthly

rainfall of 150mm – 300mm, short rain season is between

October and December with monthly average rainfall ranging

from 75mm- 100mm.

Figure 1 KIWALANI AREA

LITERATURE REVIEW

Ground water is water located beneath the ground surface in soil

pore spaces and in the fractures of litho logical formations.

This water forms as the part of the natural water cycle present

in aquifers (layer of porous substrate that contains and

transmits groundwater). Groundwater has many very important

functions in agricultural, municipal and industrial use. It is of

vital importance to maintain the appropriate level of quantity

and quality of discharging groundwater as this has significant

impact on surface-water quality.

Most of people live at Kiwalani depend much on ground water as

main source for water supply. Whereby there many individual wells

at their residential areas and some are company wells that supply

water by sell to people, these wells has help to reduce water

shortage at Kiwalani since there is no DAWASA water to the most

of Kiwalani streets.

Ground water origin and occurrence

Ground water occurs in both consolidated and unconsolidated

formations. Ground water bearing formations sufficiently

permeable to transmit and yield water in usable quantities are

called aquifers, which can be categorized into three types

confined aquifer, unconfined aquifer and leaky aquifer (semi

confined aquifer).

Water yield from these three types of aquifer may differ in term

of the quantity and quality. In most of Dar es Salaam coastal

areas the water table is very high means groundwater is easy to

extract some distance below ground surface.

a) Confined aquifer

It is a formation in which ground water is held under

pressure between two impermeable beds or aquiclude. A

confined aquifer is always under pressure because of the

weight of the overburden and hydrostatic head. This can

create artesian wells that flow freely without a need of the

a pump or rise to a higher elevation than the static water

level (SWL) at the above, unconfined aquifer if a well

penetrates the confining layer, water will rise to the

piezometric level.

b) Unconfined aquifer

It is a formation which is bounded below an aquiclude and

above by water ta

Since ground water occurs within geological formation is

important also to know the hydrological classification of the

geological form

Aquitards are geological formation or bed of low permeability

along an aquifer. An aquitard is a zone within the earth that

restricts the flow of groundwater from one aquifer to another.

Aquiclude is a formation which contains water but cannot transmit

it rapidly enough to significant supply to well or spring

Aquifuge- are geological formations that has no interconnected

openings therefore cannot hold or transmit water. Aquitards

comprise layers of either clay or non-porous rock with low

hydraulic conductivity

Factors influencing the ground water occurrence

Hydraulic properties

Are the properties that govern ground water storage and

transmission. This includes pores, lava tubes, solution

cavities, bedding planes, faults, unconformities, intrusive

contacts

Geological frames work

This includes topography, types of geology formation,

physical and chemical characteristics of unconsolidated

deposit overlaying bedrocks.

Climate

Climate has great influence on the occurrence of ground

water, for example in area having sufficient amount of

rainfall the level of ground water will rise due to the

water which percolated into the ground (ground water

recharge)

GROUND WATER QULITY

Ground water quality tends to vary due to different geological

formation. The chemical and biological character of ground water

is acceptable for most uses. The quality of ground water in some

parts of the country, particularly shallow ground water, is

changing as a result of human activities. Ground water is less

susceptible to bacterial pollution than surface water because the

soil and rocks through which ground water flows screen out most

of the bacteria. Bacteria, however, occasionally find their way

into ground water, sometimes in dangerously high concentrations.

But freedom from bacterial pollution alone does not mean that the

water is fit to drink. Many unseen dissolved mineral and organic

constituents are present in ground water in various

concentrations. Most are harmless or even beneficial; though

occurring infrequently, others are harmful, and a few may be

highly toxic.

Water is a solvent and dissolves minerals from the rocks with

which it comes in contact. Ground water may contain dissolved

minerals and gases that give it the tangy taste enjoyed by many

people. Without these minerals and gases, the water would taste

flat. The most common dissolved mineral substances are sodium,

calcium, magnesium, potassium, chloride, bicarbonate, and

sulfate. In water chemistry, these substances are called common

constituents.

Factors affecting ground water quality

Chemistry of soil and geologic layers

Depth of aquifer from ground level

Biological activities

Domestic and industrial waste if the source is near houses

or industries

GROUWATER POLLUTIONS

The simplest groundwater pollution definition would be an

introduction of certain pollutant(s) into the groundwater which

reduces the quality of groundwater making its use very limited,

or in some cases impossible. Many different chemicals and various

synthetic products we use today are usually the main causes of

groundwater pollution.

In assessment of the ground water quality is important to know

various ways that can result to ground water pollution. The

pollutants on groundwater can be due to

Waste disposal

Saline water intrusion

Pollution under natural condition

Leachate generation

Waste disposal

Most pollution originates from the disposal of waste water

following the use of water for any of a wide variety of purposes.

Thus a large number of source and causes can modify the quality

of ground water. The principle causes of ground water pollution

are municipal, industrial, agriculture and miscellaneous, for

wastes from industries and municipal most of it are buried into

the ground as a result when the level of ground water rises the

solids dissolves in the water thus leads to the contamination of

ground water.

At Kiwalani ward in one of the street called Minazi mirefu waste

disposal is done at wetland called Gombo which is free for all

people to disposal their waste, this place was selected as

dumping area because they wanted the wet land to disappear

because during heavy rain it used to flood the house nearby. But

now it has been a big problem if the floods happen all wastes are

carried back to people’s house example in 2014 on March one of

children was killed because of heavy rainfall that course flood

at dumping area.

Figure3: Gombo dumping area at Minazi mirefu in Kiwalani

Saline water intrusion

Saline water is most common pollutant in fresh ground water. This

where saline water displaces or mixes with fresh water in the

aquifer. The phenomenon can occur in deep aquifer with the upward

advance of saline water of geologic origin, in shallow aquifer

from surface waste discharges and in coastal aquifers from an

invasion of sea water.

Figure 4: Shows saline intrusion

Pollution under natural condition

The quality ground water at any particular location in an aquifer

is determined by the chemical composition of the precipitation

that recharges the aquifer and the sequence of the rock types

through which the water has passed as it has traveled from the

earth surface to that. Because of the diversity of the geologic

environments, natural ground water quality varies considerably

from one place to another

Leachate generation

This result from the pit latrine, septic tanks, ponds and

polluted wet lands, most of Kiwalani area ground water quality

has been loose due to Leachate generation from the pit latrines

which are very close to their wells.

Figure 5: shows the source of ground water pollution

WATER QULITY

Water quality describes the condition of the water including

chemical, physical and biological characteristics. It is measured

by several factors such as the concentration of dissolved oxygen,

bacteria levels, the amount of salt and amount of the suspended

in water (turbidity).Determination of water quality is typically

made relative to the purpose the water can be for drinking or

other activities, poor quality of water can pose a health risk

for people and ecosystem.

In Tanzania water quality base on domestic water supplied to

the community should be free from particles and pathogens

hazardous to human being and livestocks whilst taste, colour and

odor should be kept at low limits acceptable to consumers. Water

qualities used in Tanzania are the WHO international standards

and Tanzania temporary standards. These standards are found in

water design manual 0f Tanzania 2009 in chapter tree page 61.

WATER PARAMETERS

pH

PH is a measure of a solution's acidity. In water, small numbers

of water molecules (H 2O) will break apart or disassociate into

hydrogen ions (H+) and hydroxide ions (OH-). Other compounds

entering the water may react with these, leaving an imbalance in

the numbers of hydrogen and hydroxide ions. When more hydrogen

ions react, more hydroxide ions are left in solution and the

water is basic; when more hydroxide ions react, more hydrogen

ions are left and the water is acidic. PH is a measure of the

number of hydrogen ions and thus a measure of acidity.

PH is measured on a logarithmic scale between 1 and 14 with 1

being extremely acid, 7 neutral and 14 extremely basic. Because

it is a logarithmic scale there is a tenfold increase in acidity

for a change of one unit of pH, e.g. 5 is 100 times more acid

than 7 on the pH scale. The largest variety of freshwater aquatic

organisms prefers a pH range between 6.5 to 8.0.

Turbidity

Turbidity is a measure of how particles suspended in water affect

water clarity. It is an important indicator of suspended sediment

and erosion levels. Typically it will increase sharply during and

after a rainfall, which causes sediment to be carried into the

creek. Elevated turbidity will also raise water temperature,

lower dissolved oxygen, prevent light from reaching aquatic

plants which reduces their ability to photosynthesize, and harm

fish gills and eggs. Material that causes water to be turbid

includes; clay, Silt, microscopic organisms, plankton and soluble

colored organic compounds.

In Kiwalani area water from shallow well is seems to have of high

turbidity since most of pit latrine are near the wells during

rainy season there is Leachate from pit latrine that contact with

ground water.

Figure 6:water from shallow well at Kiwalani

Conductivity

This is a measure of the capability of a solution such as water

in a stream to pass an electric current. This is an indicator of

the concentration of dissolved electrolyte ions in the water. It

doesn't identify the specific ions in the water. However,

significant increases in conductivity may be an indicator that

polluting discharges have entered the water.

Every creek will have baseline conductivity depending on the

local geology and soils. Higher conductivity will result from the

presence of various ions including nitrate, phosphate, and

sodium.

Table2, below shows the variation of electrical conductivity for

different water sources

Water Conductivity TemperaturePure water 0.055 250CDistillated water 0.5-5 250CRain water 5.0-30 250 COcean water 4500-55000 250CNormal ground

water

30-2000 250C

The basic unit of measurement for conductivity is micromhos per

centimeter (µmhos/cm) or microsiemens per centimeter (µS/cm).

Either can be used, they are the same. It is a measure of the

inverse of the amount of resistance an electric charge meets in

traveling through the water. Distilled water has a conductivity

ranging from 0.5 to 3 µS/cm, while most streams range between 50

to 1500 µS/cm. Freshwater streams ideally should have

conductivity between 150 to 500 µS/cm to support diverse aquatic

life

Dissolved Oxygen

Dissolved oxygen is oxygen gas molecules (O2) present in the

water. Plants and animals cannot directly use the oxygen that is

part of the water molecule (H2O), instead depending on dissolved

oxygen for respiration. Oxygen enters streams from the

surrounding air and as a product of photosynthesis from aquatic

plants. Consistently high levels of dissolved oxygen are best for

a healthy ecosystem.

Levels of dissolved oxygen vary depending on factors including

water temperature, time of day, season, depth, altitude, and rate

of flow. Water at higher temperatures and altitudes will have

less dissolved oxygen. Dissolved oxygen reaches its peak during

the day. At night, it decreases as photosynthesis has stopped

while oxygen consuming processes such as respiration, oxidation,

and respiration continue, until shortly before dawn.

Human factors that affect dissolved oxygen in streams include

addition of oxygen consuming organic wastes such as sewage,

addition of nutrients, changing the flow of water, raising the

water temperature, and the addition of chemicals.

Dissolved oxygen is measured in mg/L.

0-2 mg/L: not enough oxygen to support life.

2-4 mg/L: only a few fish and aquatic insects can survive.

4-7 mg/L: good for many aquatic animals, low for cold water fish

7-11 mg/L: very good for most stream fish

Nitrate

Nitrogen is abundant on earth, making up about 80% of our air as

N2 gas. Most plants cannot use it in this form. However, blue-

green algae and legumes have the ability to convert N2 gas into

nitrate (NO3-), which can be used by plants. Plants use nitrate

to build protein, and animals that eat plants also use organic

nitrogen to build protein. When plants and animals die or excrete

waste, this nitrogen is released into the environment as NH4+

(ammonium). This ammonium is eventually oxidized by bacteria into

nitrite (NO2-) and then into nitrate. In this form it is

relatively common in freshwater aquatic ecosystems. Nitrate thus

enters streams from natural sources like decomposing plants and

animal waste as well as human sources like sewage or fertilizer.

Nitrate is measured in mg/L. Natural levels of nitrate are

usually less than 1 mg/L. Concentrations over 10 mg/L will have

an effect on the freshwater aquatic environment. 10 mg/L is also

the maximum concentration allowed in human drinking water by the

U.S. Public Health Service. For a sensitive fish such as salmon

the recommended concentration is 0.06 mg/L.

Water with low dissolved oxygen may slow the rate at which

ammonium is converted to nitrite (NO2-) and finally nitrate

(NO3-). Nitrite and ammonium are far more toxic than nitrate to

aquatic life.

Chloride ion

Chloride ions are most presence in chlorine gas and it compounds.

Chlorine is a greenish-yellow gas that dissolves easily in water.

It has a pungent, noxious odor that some people can smell at

concentrations above 0.3 parts per million. Because chlorine is

an excellent disinfectant, it is commonly added to most drinking

water. In parts of the world where chlorine is not added to

drinking water, thousands of people die each day from waterborne

diseases like typhoid and cholera. Chlorine is also used as a

disinfectant in wastewater treatment plants and swimming pools.

If water contains a lot of decaying materials, free chlorine can

combine with them to form compounds called trihalomethanes or

THMs. Some THMs in high concentrations are carcinogenic to

people. Unlike free chlorine, THMs are persistent and can pose a

health threat to living things for a long time (carcinogenic

health problems). In usage of chlorine for water treatment should

be well careful because much concentration can irritate eyes,

nasal passages and lungs, it can even kill in a few breaths and

the formation of THM compounds must be minimized because of the

long-term health effects.

Chlorine is also used as a disinfectant in wastewater treatment

plants and swimming pools. It is widely used as a bleaching agent

in textile factories and paper mills, and it’s an important

ingredient in many laundry bleaches.

Hardness

Hardness is a measure of the amount of calcium and magnesium in

water. When water is combined with carbon dioxide to form very

weak carbonic acid, an even better solvent results. As water

moves through soil and rock, it dissolves very small amounts of

minerals and holds them in solution. Calcium and magnesium

dissolved in water are the two most common minerals that make

water "hard."  The degree of hardness becomes greater as the

calcium and magnesium content increases and is related to the

concentration of multivalent cations dissolved in the water.

Hard water interferes with almost every cleaning task from

laundering and dishwashing to bathing and personal grooming.

Clothes laundered in hard water may look dingy and feel harsh and

scratchy. Dishes and glasses may be spotted when dry. Hard water

may cause a film on glass shower doors, shower walls, bathtubs,

sinks, faucets, etc. Hair washed in hard water may feel sticky

and look dull. Water flow may be reduced by deposits in pipes.

WATER TREATMENT

Water treatment is, collectively, the industrial-scale processes

that make water more acceptable for an end-use, which may be

drinking, industry, or medicine. Water treatment is unlike small-

scale water sterilization that campers and other people in

wilderness areas practice. Water treatment should remove existing

water contaminants or so reduce their concentration that their

water becomes fit for its desired end-use, which may be safely

returning used water to the environment.

The processes involved in treating water for drinking purposes to

provide a safe source of water supply may be solids separation

using physical processes such as settling and filtration, and

chemical processes such as disinfection and coagulation.

For most people, the term "water treatment" refers to potable

water production from raw water, whereas "wastewater treatment"

refers to the treatment of polluted water, where the pollution

could be from human waste, industry, agricultural waste or other

sources of pollution. Water treatment will depend on water source

the water is collected.

Portable water purification

Water purification is the removal of contaminants from untreated

water to produce drinking water that is pure enough for the most

critical of its intended uses, usually for human consumption.

Substances that are removed during the process of drinking water

treatment include suspended solids, bacteria, algae, viruses,

fungi, minerals such as iron, manganese and sulfur, and other

chemical pollutants such as fertilizers.

Measures taken to ensure water quality not only relate to the

treatment of the water, but to its conveyance and distribution

after treatment as well. It is therefore common practice to have

residual disinfectants in the treated water in order to kill any

bacteriological contamination during distribution.

World Health Organization (WHO) guidelines are generally followed

throughout the world for drinking water quality requirements. In

addition to the WHO guidelines, each country or territory or

water supply body can have their own guidelines in order for

consumers to have access to safe drinking water.

Methods for Ground water treatment

Groundwater has been a preferred source of drinking water because

of the general perception that it is of higher quality, less

vulnerable to contamination, and requires less intensive

treatment than other types of water.

1. Pump-and-treat is one of the most widely used ground-water

remediation technologies. Conventional pump-and-treat

methods involve pumping contaminated water to the surface

for treatment. This guide, however, uses the term pump and

treating a broad sense to include any system where

withdrawal from or injection into ground water is part of a

remediation strategy. Variations and enhancements of

conventional pump and treat include hydraulic fracturing as

well as chemical and biological enhancements.

2. Air stripping is a process in which contaminated water

is passed through a column filled with packing material

while upward-flowing air removes chemicals from the water.

In general, these vapors should not be released directly

into the air and therefore, should be appropriately treated.

3. Filtration Method,

Filtration simply stated, removes suspended matter from

water by mechanical "screening" (Sometimes the word

"filtration" is used [incorrectly] to refer to all types of

water treatment). Basic filters usually are porous beds of

insoluble material. Other examples include cast forms,

plates of sheet material, synthetic membranes, and finely

perforated plastic or specially sized beds of inert

particles. Suspended silt, clay, colloids, and some

microorganisms are removed by the filtration process. Simple

cartridge filters may be effective for low levels of

turbidity.

4. In-situ Flushing

Oil flushing involves pumping flushing solution into

groundwater via injection wells. The solution then flow down

gradient through the region of contamination where it

desorbs solubilized, or flush the contaminants from the soil

or groundwater. After the contaminants have been

solubilized, the solution is pumped out via extraction wells

located further down gradient. At the surface, the

contaminated solution is treated using typical wastewater

treatment methods, and then recycled by pumping it back to

the injection wells (USEPA, 1991; Roote, 1997). Plain water

or carefully developed solution (e.g. surfactant/co solvent)

is used as flushing solutions. However, one must select the

type and concentration of flushing solution to optimize

contaminant desorption and solubilzation.

In-situ flushing causes less exposure of the contaminants to

clean-up personnel and the environment. It is a simple and

easy operation as compared to other technologies. It is

applicable for a wide variety of contaminants, both organic

and inorganic contaminants. It may be a slow process when

heterogeneities such as soil layers or lenses of less

permeable (less than 10–5cm/s) or organic materials are

located within the soil horizon. Since the contaminants are

solubilized into the solution, they may be transported

beyond the extraction well and unintentional spreading of

the contamination may occur. Remediation times may be long

and the effectiveness of the process largely depends on

solution, contaminant, and soil or K.R. Reddy 268

groundwater interactions. Remediation depends strongly on

the ability of the solution to desorb and solubilized the

contaminant. The process may be costly with contamination

located at large depths or with expensive solutions and long

remediation.