ENVIRONMENTAL HEALTH(0).ppt

ENVIRONMENTAL HEALTH
BY
FRANK.S

Introduction
Environmental health is one of the disciplines of
public health.
Public health is the science and art of preventing
disease, promoting health and prolonging life.
This can be done through;
Environmental health
Control of communicable diseases
Education of individuals on personal hygiene
Early DX, RX and prevention of diseases

Introduction cont’d
Environmental health includes factors in the
environment that affect health & well being of an
individual & public at large.
Environment includes the aggregate of all
external conditions & influences that affect life &
development of an organism.
Environment includes water, air, land and inter-
relationships that exist among them and living
things.

Factors influencing E.H
1. Economy: either negatively or positively, poor
or better direction or maybe counter productive
to env’t.
2. Culture: Beliefs/taboos/customs/norms
contribute negatively/positively to env’t of
community or country
3. Political stability of a nation: contributes a lot
to good sanitation
4. Education standards
5. Religion
6. Climate

Scope of Environmental Health
1. Water quality improvement& control (safe H2O)
2. Proper disposal of human excreta
3. Management of waste/refuse
4. Sewage mgt (waste water from kitchen & sullage)
5. Control of insect vectors & rodents
6. Food quality and monitoring
7. Promotion of good housing(proper housing) to
minimize diseases related to housing
8. Promotion of occupational hygiene to improve
safety in work env’t

Scope of Environmental Health cont’d
9. Emergency measures associated with epidemic
diseases and disasters
10. Hygiene education and promotion
11. Environmental health survey

Environmental sanitation
Is the sum of all external influences & conditions
which affect health, life and growth.
It is application of effective measures to create
and maintain health env’tal conditions.
These measures include;
1. Provision of proper housing
2. Provision of safe water
3. Proper excreta disposal
4. Proper disposal of waste water e.g from
bathrooms, kitchens, wash hand basins& water
from any other domestic appliance

Environmental sanitation cont’d
These measures include;
5. Proper disposal of solid waste/refuse
6. Control of disease vectors
7. Control of pollution of air, water, land and food
Hygiene
Refers to practices that maintain cleanliness within
the body and env’t.

Sanitation
Derived from Latin word “sanitas” meaning health
It is the establishment of env’tal conditions that
are favorable to health e.g housing, water
protection, food hygiene and excreta disposal
Basic sanitation
WHO; defines it as control of those factors in man’s
physical env’t which exercises or may exercise
harmful effects on his dev’t, health & survival.
G.O.U pursues the policy of PHC of which basic
sanitation is a component.

Therefore sanitation is also defined as a process of
safe disposal of wastes & promotion of hygienic
practices that prevent transmission of waste related
diseases.
Components of basic sanitation
1. Sanitation education
2. Excreta disposal
3. Refuse/waste disposal
4. Waste water disposal
5. Removal of any pollutants which may enter
human’s body.

Importance of improved sanitation
1. Safe disposal of human excreta, refuse & waste
water are of paramount importance to health
among community served.
2. Wastes lead to contamination of soil, water
sources and food which are vehicles of disease
transmission to man.
3. Waste provide an ideal breeding
place/opportunity to certain insects e.g
mosquitoes, house flies, which transmit
diseases. It therefore essential that all wastes
are disposed off in hygienic manner.

Sanitation education
Is the process of increasing the level of awareness of an
individual or community members in order to improve
their attitudes & practices in relation to sanitation.
Limitations/constraints to sanitation education
1. Low level of community awareness
2. Harmful cultural values& practices
3. Lack of community participation& involvement
4. Lack of proper community approach
The above can reduced by community DX aimed at
getting to know the factors& situations which influence
the way the community lives.

EXCRETA DISPOSAL
Is the safe mgt of human feaces & urine in order
to prevent the occurrence of nuisances and
disease transmission.
Public health importance of excreta disposal
1. May contain pathogenic organisms or ova of
intestinal worms that cause disease.
2. Causes bad smell & un sightly conditions causing
aerial nuisances.
3. Acts as breeding place for insects& other disease
carrying vectors
4. Causes pollution of water supply & env’t

CHOICE OF TECHNOLOGY OF EXCRETA
DISPOSAL METHOD
A number of technologies for safe excreta disposal for
rural communities exist.
The criteria for adopting any technology of excreta
disposal depends on a number of factors;
1. Availability of space
2. Cost in relation to the income of the community
3. Availability of local materials
4. Existing local technologies
5. Freedom from flies, smell/odour & contamination
6. Nature of the soil
7. Sustainability

DISPOSAL METHOD CONT’D
1. Availability of space -establish/ascertain whether
there is enough space to accommodate the design in
question and future expansion for pit latrine.
2. Cost in relation to community’s income
Determine whether the proposed method to be used will
be affordable for community or not.
3. Availability of local materials
Community may not choose technology which will
involve getting materials outside its locality.
This results in failure of the proposed technology of
excreta disposal.

4. Existing local technologies
The new technology maybe resisted by the
community & so opt for the already existing ones in
the community. Care must be taken not to reject
theirs but to improve on it so as to meet proper
standards of excreta disposal.
5. Local expertise
A technology where the community participates in its
construction with the assistance of local experts
within them is preferred.

6. Nature of the soil
technology should not be affected the nature of the
soil in the community.
7. Sustainability
Technology should be easily used and maintained by
the community.
It should also last for at least five years or more
without the need for immediate changes.

METHODS OF EXCRETA DISPOSAL
Several methods ranging from bush to flush toilets
with water carried wastes.
Flush toilets aren't affordable by community
The methods of E.D should be affordable both in
construction and maintenance.
The type or method of E.D should be acceptable,
cheap to operate, maintain and safe.

1. Cat system
2. Trench latrine
3. Bucket latrine
4. Ordinary pit latrine
5. Ventilated improved pit latrine
6. Flush toilets/pour flush latrines
7. Composting latrine
8. Bore hole latrine
9. Flying latrines
10. ECOSAN (Ecological sanitation)
11. Chemical closet

CAT SYSTEM
It was adopted from the cat system of defecation
It involves digging a shallow hole in the ground &
defecating in it & covering excreta with the dug up
soils.
Application
In rural areas where there are no latrines and where
there is a lot/plenty of bush for privacy
Advantages
Cheap and requires no resources
Feaces can change to soil conditions/manure

Disadvantages of cat system
Possible contamination of both underground and
surface water sources as well as vegetables
In most cases excreta is not fully covered and hence
causes odours/bad smell and unsightly
It encourages transmission of hook worm
infestation
Access to flies and other mechanical
carriers/vectors

TRENCH LATRINE
A piece of land far way from human occupation and
source of water should be trenched.
This involves digging a trench which is relatively
60ch deep, 45cm wide and 300cm long.
The excavated soil is heaped around the trench on
the side and each user is expected to scope little of
the soil and throw it over the deposited feacal
matter.
When the trench is 30cm from the ground, it is
covered and another one is dug.
A full time employee should be available to
supervise the trenches.

TRENCH LATRINE CONT’D
Application
Temporally settlements like refugee camps, scouts,
military, building and mining camps.
Advantages
Suitable for temporally establishments
Suitable in areas where pit latrines cant be dug and
where there is no water for flush toilets
Easy and cheap to construct
Can be used in camps
Where acceptable, fertilizers can be got.

TRENCH LATRINE CONT’D
Disadvantages
Recruitment and maintenance labour force is expensive
Possible contamination of both underground and
surface water sources
It encourages transmission of hook worm infestation
(health hazard)
Flies are usually attracted to a latrine
It can sources of smell, flies, vermin
It is unsightly site
Used for short period of time
Late or uncovered excreta causes smell & attracts
animals e.g dogs

BUCKET METHOD OF EXCRETA DISPOSAL
In principle it consists of a bucket, in which excreta
is deposited and later emptied at frequent intervals
into collecting systems.
It is one of the oldest & least hygienic methods of
excreta disposal
It is used in towns and areas where there is no
piped water commonly in institutions like prisons,
refugee camps

BUCKET METHOD OF EXCRETA DISPOSAL
A squatting slab/seat is placed immediately above
the bucket which fills a few days by the excreta.
The bucket is positioned adjacent to an outside wall
and is accessible from the street/outside.
It should be made by an impervious material such
as clay or plastic. The capacity of the bucket should
not be more than 60cm3/2ft3, otherwise it will be
too heavy to carry which will lead to irregular
collection
It should have strong handles for lifting or carrying
A lid should be provided for covering

DOUBLE BUCKET METHOD/SYSTEM
In practice two buckets are used for each latrine so
that an empty one is placed soon when the full one
is taken for emptying and cleaning.
In construction, special attention should be paid to
the following;
Separate access for removal of the bucket should be
provided.
A guide should be provided so that bucket is kept in
one position
A chamber maybe built of concrete or bricks with
smooth finished wall for easy cleaning.

DOUBLE BUCKET METHOD/SYSTEM
A space between the bucket and the top of the floor of
the squatting slab should never be more than 25mm.
The bucket latrine should not be within 300cm/10ft
from the food preparation area.
Advantages of bucket system of excreta disposal
Temporally measure suitable for camps while more
permanent ones are being thought of.
Lasts longer
Can be used in heavily populated areas like prisons
Requires less labour to construct
Used in areas where soils cant allow pit construction

BUCKET METHOD/SYSTEM CONT’D
Advantages of bucket system cont’d
Double bucket system makes it more efficient
Human excreta is taken away and deposited.
Disadvantages of bucket system
Preparation is expensive coz of constant
replacement of buckets
Involves human handling of feaces & likelihood of
possible contamination
If not properly carried out, fecal matter may go
pouring over the compound and providing sites for
flies and contamination

BUCKET METHOD/SYSTEM CONT’D
Disadvantages of bucket system cont’d
A suitable disposal ground may not be available
Pollution of water and soil is almost impossible to
avoid
The bucket latrine gives a terrible stinking smell and
impossible to clean
Requires close supervision
Disposal site is always offensive and un hygienic.

PIT LATRINE
In E.A a pit latrine is the most appropriate method
of excreta disposal both in rural and peri-urban
areas where soils permit.
The simplest & cheapest improvement of a pit
latrine is to provide it with a pre-fabricated floor
inform of a squatting slab.
Advantages of a squatting slab;
The latrine will be structurally safe
Easier to clean
Using the foot rests/sanitation platforms, it will be
easier for the users to position themselves over
drop hole/squat hole so as not to soil the floor.

PIT LATRINE
Advantages of a squatting slab cont’d;
A hole with recommended dimensions too small
not to allow a child fall into it and therefore safer
and less threatening
It permits a small measure of fly control through
the use of a tight fitting lid/squat hole cover.

QUALITIES OF AN IDEAL PIT LATRINE
There should no handling of fresh feaces
There should no contamination of surface soil
There should no contamination of surface water&
underground water that may enter springs/wells
The excreta should not be accessible to flies or animals
There should no unpleasant odours/unsightly
conditions
Anal cleaning materials, water & soap for washing
hands should be available
The method should be simple, inexpensive in
construction & operation in relation to resources of the
community.

QUALITIES OF AN IDEAL PIT LATRINE
The method should be acceptable in terms of
cultural beliefs of the community.
When selecting which latrines are appropriate to a
particular community or situation, the following
points should be considered;
Availability of resources
Affordability & social acceptability of the latrine
Availability of adequate and space for future
expansion
Sanitary features& safety of the users
Problems of repair & maintenance of such latrines

CONSTRUCTION OF A STANDARD PIT
LATRINE
It can be used in both rural and peri-urban areas
where there is no piped water.
Components of a standard pit latrine;
A pit
Slab
Super structure/shelter
The size and number of apartments depend on the
choice of the house holder and number of people
to be served.

LATRINE CONT’D
1. Site
The site should not water logged
Site should not be less than 30 meters horizontal
length away from any water source.
Site should not be less than 10 meters from the
residential house.
Direction of the prevailing winds should be
considered to avoid smell.

LATRINE CONT’D
2. Pit dimensions
 Depth: should be 15ft (5meters). At this depth
there is little light and fly breeding is reduced to
minimum
Length: 4ft (1.2m) for a single stance
Width: 2ft (0.6m)
Where the soil conditions can permit, the edges of
the pit should be straight and nearer to vertical
For unstable soils, it is recommended that pit lining
to be done using bricks, stones, drums or concerete

LATRINE CONT’D
N.B: The purpose of the pit is to receive the excreta
deposit which is decomposed by bacteria and
rendered harmless.
3. Floor-can be constructed of various materials e.g
Strong well seasoned logs and mud
Reinforced concrete
Pre-cast slabs
Strong large stones
Floor should be at least 150mm above the
surrounding ground for whatever materials used.

LATRINE CONT’D
4. Foundation
Laid on a firm ground, achieved by removal of loose
top soil for a depth of 1ft or 300mm
Where depth of loose soil exceed 1.5ft or 450mm, a
concrete foundation should be laid.
Where a slab or concrete floor is to be used, a
foundation wall should be constructed to receive
the slab or concrete floor.

LATRINE CONT’D
5. Squat hole
Should be not be too large to allow children to fall
in or too small to allow soiling
Recommended size: Length 340mm, width 150mm
at the rear and 100mm at the front.
The corners should be rounded/smooth to permit
easy cleaning.
Where the squat hole is rectangular, it should be
340mm X 150mm &where the floor is made of logs
& murrum, should be brought to smooth finish

LATRINE CONT’D
6. Walls
Can be made of various materials e.g bricks, stones,
mud and wattle.
Walls should be plastered & smeared smoothly
internally and externally
Ventilators should be provided or space of 150mm
or 6 inches above the walls & below the roof should
be left all around for ventilation purposes.

LATRINE CONT’D
6. The roof
May grass, banana fibers, corrugated iron sheets,
tiles, asbestos sheets, papyrus.
Whatever materials used, the roof must be provided
with sufficient slope;
To ensure free flow of rain
Roof should have eaves to protect the walls
Roof should not leak
Roof should be firm enough to with stand wind
effects

LATRINE CONT’D
7. Privacy
The super structure should be constructed in a such
way that there is privacy of users
This can be achieved by provision of door shutters
or screen walls

Use & maintenance of pit latrine
Community should be educated on proper use &
regular maintenance of pit latrines as follows;
Don’t soil the floor, squat hole and the walls
Covering the squat hole after use but for VIP don’t
Don’t spit on the walls and floor
Regular sweeping/cleaning of the floor
Regular smearing incase of rammed floors
Regular washing/cleaning incase of slab floors
Maintenance of super structure in sound conditions
all the time.
Smoking to control smell, flies, cockroaches

Capacity & life span of a pit latrine
1. Solid accumulation rate=0.06m3/person/year
2. Number of users= 10 for average family
3. Pit volume (PV) obtained from pit dimensions
PV=0.6X1.2X5m3=3.6m3
Allowance=0.5m3
Design life span=Capacity-0.5m3
Solid accumulation rate X no of users
A standard latrine of 1.2m in length, 0.6m width and
5m deep will serve a family of 10 people for 5yrs
Life span=(5x0.6x1.2)-0.5m3 =5yrs

Advantages of a PIT LATRINE
Easy to construct
Materials for latrine construction are locally
available
Its durable
Fits all classes of people
Cheaper if temporally materials are used
Human excreta is finally deposited& disposed off
into a pit with no subsequent human handling
Simple in design & easy to construct
If properly used there is no nuisance of smell
No danger of water contamination if rules followed

Disadvantages of a PIT LATRINE
Unsuitable for heavily populated areas like barracks
If improperly constructed/maintained, it acts a
source of infections & harbors snakes, rats and flies
Inconvenient to use at night or in adverse weather
conditions since there is a distance
It needs dry porous rocky & non sandy soils for its
construction
Facilitates accumulation of human excreta which
possibly contaminate water source
Maybe a source of accidents to small domestic
animals (goats, dogs) and even children

VENTILATED IMPROVED PIT LATRINE
VIP was developed in Zimbabwe by MOH in early
1980’s as an improvement on
conventional/ordinary pit latrine.
VIP is the result of an inclusion of the vent pipe on
the ordinary pit latrine design to ventilate the pit
and reduce on the fly& odour nuisances.
It offers a safe and reliable method of excreta
disposal especially in rural areas where water is
scarce
When properly built, it is odourless & fly problem is
reduced to minimum

VENTILATED IMPROVED PIT LATRINE
VIPs are best built in single or double units for
family or as multiple compartments for institutions
e.g schools
Types of VIP latrines
1. Single pit VIP latrine
2. Alternating double pit VIP latrine
3. Multiple pit VIP latrine

1. SINGLE PIT VIP LATRINE
Designed to be used at least for 2 years
Suitable for use in rural areas/peri-urban areas
where the soils is permeable & allow digging deep
pits
2. ALTERNATING PIT VIP LATRINE
Designed to have permanent structure with two
pits used alternatively
More appropriate in urban areas where people can
afford to pay for permanent latrine
Doesn’t need to be relocated after every few years.
Suitable where there is no land for future expansion

VIP LATRINE CONT’D
3. Multiple pit VIP latrine
Designed for communal use
Each compartment is designed to last for 25 years
Multiple pits are dug adjacent to each other
Each pit divided into required number of
compartments.
Construction details of a VIP latrine
Can be made of various designs & materials
Components :
Pit, slab, super structure, vent pipe and fly screen

VIP LATRINE CONT’D
Main stages construction stages of a VIP latrine
1. Siting
2. Digging and lining the pit
3. Forming and pouring concrete for the base
4. Forming, pouring and installing the a slab
5. Construction of the super structure
6. Sensitize the users on care& maintenance of VIP
7. Testing the vent pipe

VIP Latrine construction cont’d
1. Siting
Should be sited along the dwelling house
Should be built near the house to be accessible to
the family members especially at night
Should not be less than 5 meters from the house
2. Pit
Constructed in an ordinary manner like a standard
ordinary pit latrine
Dimensions of the pit depends whether its a single,
double and multiple stances

2. Pit cont’d
For a single stance: length 1.2mX0.8m width
For double stance: length 1.8mX 0.8m width
The bottom of the pit should be at-least 1m above
the ground water level
The volume of the pit depends on the solid
accumulation rate, No. of users and the designed
life span
In practice the pit contents must be not be allowed
to reach the underside of the slab (free space of
0.5m) should be left in the design.

3. Slab
Covers the pit and has squat hole near the center
Has another hole at the back for vent pipe
Concrete slab are reinforced by metallic bars
Base on which the slab is placed should be raised
above the ground level (helps to increase depth of
the pit and also prevent the storm water from
entering the pit.

4. Foundation
 The sides of the pit should be excavated to the distance of
300mm (1ft) all round & to the depth of 200mm to provide
a firm base for the foundation wall
 A foundation wall of bricks or stones 250mm thick is
constructed to 150mm above the surrounding ground
which provides the foundation of the superstructure
 Top wall should be leveled with layer of cement motor b4
placing the slab
 The squat slab is laid on foundation wall with long side
spanning/beyond the pit & vent hole nearest the squat slab

5. Vent pipe (Flue)
The vent can be constructed from bricks over the
vent hole bonded to the adjacent wall of the super
structure
Its carried up and above the top most part of the
roof e.g 0.5m
During construction, inside plastering of every 2-3
courses should be done
The construction of the vent pipe goes concurrently
with the walls
N.B: These days plastic vent pipe are widely used.

6. Fly screen
A fly screen of PVC or stainless steel net is placed
within 150mm (15cm) before the final height of the
vent bonded with one course of brick work.
This prevents the escape of house flies
For plastic vent pipe, it come with already fitted fly
screen with vent pipe cover.

7. Super structure
External walls are laid along the external edges of
the squat slab and edges of the vent leaving one
end open
Course are built along the vent hole to form a vent
pipe/flue but plastic vent pipe its different.
One external wall is then continued 750mm (7.5ft)
beyond the open end and return inwards to form a
screen which ensures privacy of users and also
increases darkness in the squat chamber
 A lockable door can be used instead of screen wall

7. The roof
Constructed in a similar manner and conditions like
a standard ordinary pit latrine.
The space between the roofing materials and the
vent should be properly sealed off to prevent
leaking during rainy season

How a VIP latrine works
 Works well by employing forces found in nature;
1. Movement of air in the vent pipe
2. Instinctive behaviour of flies
 Air is sucked out of the vent pipe by air passing across the
top of the vent pipe
 Air is forced to raise up the pipe & is replaced by new air
which is sucked in the squat hole in the slab
 The squat hole acts like air inlet & vent pipe like an exhaust
pipe of the vehicle
 In the VIP, air is continuously passing through the squat
hole and the vent pipe is often raising it at rate of over
1m/s when good breeze is blowing.

When this air mov’t is taking place, it is impossible
for the smelly gases/foul in the pit to escape
through the squat hole in the house latrine.
All odours (smell) pass up the pipe and are diluted
in the atmosphere
The interior of the latrine/super structure remains
odourless.
Although wind is normally the main force which
draws in air through the squat hole, not the only
mechanism of action of VIP, on hot days, the pipe
ventilates with wind, the sun heats the pipe, this in
turn heats up the air inside the pipe.

 Hot air raises & this will pass up the pipe & cool air is drawn
into the pipe from the pit thru squat hole
 This mechanism works well in a thin walled vent pipes
which heat up quickly like plastic vent pipes.
1. Control of odour/smell
 Current of air blowing across the exposed vent creates
suction action which cause off smelly air to raise up the
vent to the open air/atmosphere.
 This action creates a vacuum in the pit which attracts fresh
air in the pit thru squat hole
 There is continuous circulation of air in & out of the pit thus
carrying away foul gases leaving the squat chamber
odourless

2. Control of flies
VIPs are very effective at controlling flies.
Vent is constructed directly over the pit and carried
up, above & over the roof.
This creates external lighting thus admitting light
into the pit.
Squat hole is within the superstructure which is
semi darkness, flies are instinctively attracted by
light within the pit.
 Flies that may have found their way into the pit or hatched
out in the pit will try to find there way out to open thru the

2. Control of flies cont’d
Since the vent pipe is provided with fly screen, the
flies will be trapped and eventually die due to
starvation in addition to heat and gaseous
emissions from the pit.
The efficiency of the pipe can be demonstrated by a
smoke test.

Efficiency of ventilation
Varies with the type of pipe used & direction of
structure in relation to wind.
If the latrine structure opening is facing into the
wind direction, more air will pass through the
latrine/squat hole compared with latrine with an
opening facing away from prevailing wind
To ensure effective ventilation of the pit, the
following should be adhered to;

Efficiency of ventilation cont’d
1. Vent pipe should have smooth internal finishing to
ensure un obstructed air entry and circulation
2. Vent pipe should have direct communication with
the pit
3. Vent should be above the top most part of the roof
at height of 0.5m as recommended
4. Location of the vent should ensure un obstructed
flow of wind and direct exposure to sunlight.

Maintenance of VIP latrine
 Very easy to maintain and clean
 Cleaning should done regularly
 Repair of any part of the latrine is easy since it can be
done by local people
 A disinfectant/a bleech should be used for cleaning the
floor. Strong chemicals should not be used coz interfere
with anaerobic biological digestion of excreta
 Two part of the VIP need periodic inspection;
1. Fly screen at the top of the vent should be cleared off
materials which may block it
 Fly screen should be replaced in case its torn
2. The area around the edge of the foundation should be

Advantages of VIP latrine
If properly constructed, used & maintained should;
 Control odours within the squat chambers hence
can be placed near residential house
 Control flies, reducing their population and
transmission of diseases
 Slab provides an impervious easily cleanable floor
 Slab can be re-used after the pit has been filled up
 Water is not needed during defeacation/use
 Easy to construct
 All types of anal cleaning materials can be used
 Can easily be adopted in rural communities

Disadvantages of VIP latrine
 Added cost in construction& provision of vent pipe
 Continuous emission of foul gases into air polluting
the atmosphere
 Heavy weight slabs renders transportation a
problem more so when communities are not
assisted
 Underground water can be polluted/contaminated
 Difficult to construct in rocky areas & wetlands
 May not be readily acceptable due to cultures &
taboos of the local people.
 And others

Promotion of latrine construction use
Steps in provision, use & maintenance of latrines
1. Create awareness on sanitation
2. Conduct abase line survey
3. Plan community meeting with opinion leaders, NGOs,
local leaders & administrators
4. Hold meetings with the community on sanitation with
emphasis on provision& use of latrine
5. Where health committees are non existence, find out
reasons and initiate their formation
6. Train local technicians during the construction oof
demonstration latrines in some public institutions e.g
schools, health units

Promotion of latrine construction use
Steps in provision, use & maintenance of latrines
cont’d
 Mobilize community to construct& use the
facilities
 Subsidize cost of slabs for house hold latrines
 Distribute slabs at central points within
communities
 Hold meetings regularly to assess the progress of
latrine construction and use
 Extension workers should monitor the progress
and take action.

Alternating twin/double VIP
 Used where pits cannot be dug deep enough due
to rock or high water table
 Can also adopted where two adjacent pits are used
alternatively so that when one is in use, the other
is resting
 When one pit is full, its squat hole is covered
blocked/covered & the other pit opened.
 The filled latrine is allowed to rest for a minimum
of 1 yr while the pit contents are being broken
down by anaerobic oxidation, after which the pit
contents maybe used as manure.

Alternating twin/double VIP cont’d
 The double pits must be completely separate from
each other & each pit is provided with its own pipe
 Since pit contents are removed after settling,
latrine is very suitable for urban & densely
populated areas where digging of new latrines may
not be possible

Alternating/double VIP diagram

Multiple Pit VIP latrine
 Suitable in situations with many users e.g schools,
market places, prisons & where single pits are too
expensive
 Made of dug trench and on top are required
number of latrine compartments
 Compartments must be portioned from top to
bottom so that there will be complete separation
 Each compartment must be ventilated separately
so as not to interfere with pit ventilation.

CHEMICAL CLOSETS
 Excreta is deposited into a tank containing water
and chemical e.g caustic soda.
 The chemical disinfects & liquefies the excreta,
removes the smell
 Also kills eggs of various worms
 These days its more like a water carriage
system/flush toilet than conservancy system since
excreta is flushed through a closet pan into a tank
fixed below it
 In the old system, the seat was provided and
excreta was deposited straight into a water tank

Chemical closets cont’d
 Commonly used in aircrafts, ocean lines, long haul
buses, caravans, camps, trains & even in individual
houses.
 When the tank is full or aircraft, vessel or vehicle
reaches its destination, the contents of the tank
are discharged into an existing sewerage system.
 With proper operation, it can be very satisfactory
and can even be used inside a house.
 Its most suitable in planes, ships etc

Disadvantages of chemical closets
 Can’t withstand abuse i.e only absorbent tissue
can be used.
 Expensive to construct and maintain
 Can produce serious odour nuisance if poorly
maintained
 Discharge into public sewers may cause flood and
shock loading
 Tank used is usually too small for communal use
e.g markets or schools

POUR FLUSH LATRINE
 Uses water to transport excreta from the
receptacle to the disposal pit/septic tank.
 Has water seal which makes it hygienic
 Pit is provided either at lower side of the latrine or
under the receptacle
 More like water carriage system but instead of
using flushing apparatus, water is poured into the
receptacle to push the excreta into the pit.
 Very convenient where there is no adequate
water& for persons who use water for anal
cleaning.

POUR FLUSH LATRINE CONT’D
 Composed of flush bowl/receptacle, pit and super
structure
 A pour flush bowl/receptacle may or may not be of
pedestal type.
 Water forms a seal in the trap below & is an
integral part of the bowl
 The receiving pit maybe directly below the bowl or
a few meters away from the toilet
 A discharge pipe take excreta from the bowl to the
pit
 Super structure should have all the requirements of a pit
latrine.

 Seal underneath the bowl traps water & prevents
foul gases from escaping thru to the latrine
 After defeacation, a liter of water is poured into
the bowl.
 This water pushes the excreta into the pit leaving a
little behind to form the seal in trap
 Two pits are used alternatively so that while one is
in use, the other is resting
 When the pit fills up with sludge, it is then closed
and the other pit opened
 Excreta in the pit is broken down anaerobically

 To prevent water logging, there should be plenty of
space between the two pits.
The pit
 Two pits should be dug to be used alternatively
 It takes about two years before a pit needs
emptying
 The pit may be directly under the bowl or a few
meters away
 It must be located away from any underground water
source
 Volume of the pit is determined by the No. of users, solid
accumulation rate & No. of yrs pits to be used b4 filling up

The pit
 The distance between pits should be as far as
possible & never less than their effective depth or
one meter, which is ever greater.
 Pits should be lined to their full depth with bricks
or stones or concrete with open joints or leaching
holes should be provided in the lining to allow
water seepage into the ground.
 Where water table is high, over the ground pits or
tanks may be used.

The Cover
 Pit is usually covered with reinforced concrete slab
with bowl placed at the centre of the slab.
 Bowl/pan/receptacle
 Usually 450mm long& about 200mm wide and
oval/pear shaped
 The outlet is located at the rear/hind part and
bottom slopes at an angle of 25-30 degrees
towards the back
 Materials for the bowl maybe cement mortar, glass
fiber, glazed ceramic or molded plastic.

The Cover
 Where people prefer to sit, pedestal unit may be provided
 The trap should have the depth of the seal of minimum of
20mm (2cm) and an out let of minimum of 70mm (7cm)
diameter
Discharge pipe
 Should be a min of 75mm diameter& have a slope of 1:30
to be self cleaning.
 Materials used maybe PVC, asbestos cement, cast iron or
any other corrosion resistant material
 Where the pipe enters the pit, it should protrude distance
not less than 100mm to prevent excreta from running
down the wall

The super structure
 Should be minimum of 0.8m wide and 1.0m long
 Should be made up of locally available materials
e.g bricks, blocks, stones, timber etc
 The roof should be minimum of 2m high

Advantages of pour flush latrines
 Low cost sanitation technology
 Suits many situations since its very adaptable
system
 Can be placed inside houses including upper floors
of multi story buildings
 Pit can be placed under foot paths or roads
 No nuisances of smell or flies
 Can easily be upgraded to a water carriage system
when the supply of water improves
 Convenient for densely populated areas

Disadvantages of pour flush latrines
 Requires constant supply of water
 Bulky anal cleaning materials may cause blockage
 May not be successful in adverse areas with rocky
ground, high water table or very impermeable soils
 Likely pollution of under ground water sources
 Pits must be accessible for emptying by vehicles
(cesspool emptier)

ASSIGNMENT
Read and make notes about the following;
1. Bore hole latrines
2. Flush toilets
3. Ecological sanitation latrine (ECOSAN)

SOLID WASTE/REFUSE MGT
Definition of terms
 A waste: something the owner no longer wants at
a given place & time & has no current perceived
market value (WHO).
 Garbage: all waste which are readily biodegradable
and may result from growing, handling &
consumption of food e.g kitchen waste, banana
peelings etc.
 Litter: various light materials discarded in public
places e.g papers, poly-ethene, bus tickets, sweet
wrappings etc.

Definition of terms cont’d
 Rubbish: all non biodegradable wastes except
ashes. It includes carbon papers, card boards,
plastics and rubber.
 Solid waste: house refuse & has same meaning as
refuse, so the two are used interchangeably.
 Refuse management: is the control of generation,
storage, collection, transportation, separation,
recovering, treatment and safe disposal of solid
waste.
 Leachate: thick liquid that leaks from tipped &
decomposing refuse. Can be source of water
pollution& may habour pathogenic organisms.

Types of solid waste
1. Industrial wastes: varies from industries or
activities going on in an industry e.g an industry
dealing with food processing will have remains of
various foods, peelings, old tins, poly-ethene bags
etc
2. Street waste: waste that accumulate on streets&
roads as a result of activities taking place there e.g
plastic bags, poly ethene, boxes, dust
3. Domestic waste: waste from homes & forms a
bulky waste e.g potato, cassava, matooke peelings,
paper, dust. Hobson (1969) classified domestic
waste as follows;

Categories of domestic waste
1. Fine matter (mostly ashes and dust)
2. Cinders (remains of burnt coal and charcoal)
3. Paper and card boards
4. Textile and rags
5. Glass (broken bottles and other glasses)
6. Plastics
7. Garbage
8. Un classified debris e.g wood, leather, stones

Categories of domestic waste cont’d
N.B: Domestic waste have some salvage potential value i.e
can be used in other forms
 Screened dust used in covering refuse during tipping.
 Paper can be separated & used for making card boards
 The main is to try to treat waste, recycle and re-use it in
other forms.
4. Commercial waste: refuse from big establishments e.g
supermarkets, shops, hotels, bookshops, schools etc
5. Medical waste: Waste generated from health facilities e.g
non infectious waste, infectious waste, highly infectious
waste, pharmaceutical waste (see details later)

Methods of solid waste disposal
 The choice of any method depends on climatic
conditions & economy of the place or town.
 Hygiene, social benefits & availability of tipping
sites should be considered.
 Method of disposal depends on the factors
below;
 Cost of the method
 Constraints of the method/limitations
 Potential use of power or heat generated
 Health of the public & workers
 Quantity & xtics of solid waste to be dealt with & ways in
which it can be changed

1. Crude dumping
2. Separation and incineration
3. Controlled tipping
4. Composting
5. Controlled burning
6. Disposal into water bodies (lakes/rivers/seas)
7. Animal feeding
8. Disposal of the dead/burying of the dead

1. Controlled tipping
Before solid waste are taken to the tip, a site is
selected basing on the following;
 Proximity of the building in relation to the tip
 Protection of water sources & recreation areas
 Cost of the land
 Future use of the area
 Suitability of the soil as a covering material
 Accessibility to the site
 Direction of the prevailing wind

Operation of controlled tipping
 Confine, compact and cover (CCC)
 Involves tipping of solid waste in layers,
compacting each layer and covering it with inert
materials purposely to prevent breeding of
mosquitoes, rodents and flies.
 This also prevents smell nuisances, contamination
of ground water sources and scavenging.
 Solid wastes are dumped in layers not more than
2m in depth and covered with layer of earth/soil tp
depth of 225mm(22.5cm).
 Decomposition process is similar to that in
composting

Advantages of controlled tipping
 Minimizes smell
 Prevents light materials from being blown away by
wind
 Fire hazards are reduced
 Makes the tip less attractive to birds
 Eliminates insects & rodents breeding
 Cheap and simple to operate
 Low lying areas can be reclaimed for agriculture
 Provides good conditions for biological
biodegradation of organic matter at the tip

Disadvantages of controlled tipping
 Not always easy to obtain a site at reasonable
distance at low cost or price
 Needs close supervision or else the tip maybe
turned into a crude dumping site
 May encourage rodents and flies breeding
 N.B: When the tip is finished, grass should be
planted on the surface and along all sides.

2. Crude dumping
 Method of solid waste disposal in which solid
wastes are disposed off without ant precautions.
 Refuse is either disposed off in a chosen area or
dumped any where.
 Such dumping causes a lot of nuisances and many
health hazards arise a result of decomposition.
 Wood (1986) described nuisances which arise from
crude dumping as disadvantages (see next slide)

Disadvantages of crude dumping
 It is unsightly
 Attracts insects and vermin such as house flies,
rats and cockroaches
 Spread of communicable diseases through
mosquitoes breeding & water contamination
 Can cause fire outbreaks
 Produces offensive smell/bad odour
 Pollution of air, water and food
 Crude dumping is an insanitary method of solid
waste disposal & must be discouraged.

3. Separation & incineration
 Incineration is burning of rubbish.
 Maybe done in drums, trenches of bricks built or
brick built bins.
 Separation & incineration involves separation of
some fraction of waste either by mechanical or
manual means.
 Dust& cinder are 1st removed through rotating
screens, ferrous metals taken out by powerful
electromagnets.
 The remaining solid waste are passed on moving
belt from which papers, rags, grass, bones are
removed or picked out manually.

Direct incineration
 Involves burning of solid waste.
 Burning is done in a refuse pit or an area set aside
for that purpose.
 Burning can either be in brick incinerators or by
using a drum as an improvised incinerator.
 In towns, solid wastes are burnt either crude or
after separation.

Advantages of incineration
 Less land required
 Central location can be used
 Many solid waste are burnt to ashes
 Climatic or unusual weather conditions do not
affect the operation of the incinerator
 Incinerators are flexible in operation coz they work
for 8, 12, 16 & 24 hours depending on the amount
of waste to be burnt.
 Possible to raise some income through salvage of
the generated power and steam.

Disadvantages of incineration
 Expensive/costly to buy and install
 Operating costs are relatively high and skilled
employees required for solid separation and
maintenance
 Maybe problem of obtaining a site suitable for
installing the incinerator
 Pollution if air, smell of gases from incinerators

4. COMPOSTING
 Compost is a humus like material that results from
microbial action on biodegradable solid waste.
 It is stable, ordourless and un attractive to flies.
 Composting is a cheap and convenient method of
refuse disposal which is recommended.
Aim of composting
 To convert a major portion of solid waste into
manure

USES OF COMPOSTING
 Can be used as fertilizers /agricultural purposes
 Less land/compost can be reused
 Doesn’t encourage breeding of flies, rats etc
 It is odourless
 Used as soil conditioner
 Used to increase organic content of soil so as to
improve soil structure
 Provide micro nutrients and adequate quantities of
basic plant nutrients e.g nitrates & phosphates

TWO PHASES OF COMPOSTING
1. The use of the method & equipment which
facilitate decomposition of organic matter under
controlled conditions so as to avoid risks to health
and environment.
2. Extraction of constituents of waste which would be
undesirable in the compost. Solid waste intended
for composting fall under the following classes;
 Materials which form compost for use as organic matter
 Materials that must be salvaged 1st & then sold for
recycling
 Remains that have no use in composting can be taken to
the tip to be used as a cover material.

HOW IS COMPOSTING MADE/PROCESS
 Micro organisms need moisture & time to turn
garbage or sludge (biodegradable waste into
compost).
 If an aerobic process is preferred, there must be
supply of oxygen to the bacteria.
 Anaerobic composting is slower than aerobic
composting and the product is inferior in terms of
nutrients.
 Anaerobic composting is also associated with
odour problems

HOW IS COMPOSTING MADE CONT’D
 Aerobic composting is faster and associated with
high temps which have adverse effects on the fly
larvae and pathogenic bacteria.
 The weed seeds are also inactivated by high temps
 The simplest method of composting is to place the
refuse into a ditch/manure pit/composting pit in
alternative layers, then covered with soil/grass and
leave it for aerobic composting to take place.
 Fermentation decomposes the refuse which
should be turned at intervals to aerate the
materials after 30days, then after 60days.

HOW IS COMPOSTING MADE CONT’D
 After 90days (3 months), the refuse is ripe and
maybe put on land as fertilizers.
 Turning tends to shift the warmer materials in the
center to the top and vise versa.
 N.B: When moisture content is high, turning 3-4
times a week is encouraged.
 The process maybe mechanical or manual
depending on the quantity of refuse to be
composted.
 The moisture content must always be controlled.
 N.B: Turning waste helps to lower temp to low level
where aerobic bacteria can survive.

COMPOSTING PROCESS CONT’D
Dimensions of compost pit
 May vary but reasonable pit is 1.5m deep, 3.0m
wide and 4.5m long
 Consists of hand dug hole
 In common practice, two holes are dug adjacent to
one another so that when one is 6 inches full to
the ground level, the adjacent one is used.
 In practice every day collection, a layer of soil is
poured.

Benefits of composting
 Can be used for agricultural purposes
 Good for soil conservation
 Doesn’t cause any health hazards
Problems of composting
 Maybe insufficient market for the compost manure
 Transportation to the places of application maybe
a problem or not available
 Waste that contains sufficient amount of metals
are not suitable for composting
 N.B: This methods works only on biodegradable
waste.

ANIMAL FEEDING
 Garbage is collected from hostels, hospitals,
schools and other institutions and then fed to
animals.
 Animals include; pigs, cows, goats, sheep, dogs etc
 It is mainly used in urban areas where a lot of
refuse is generated.
 Assignment: Read and make notes about;
1. Advantages of animal feeding method of waste
disposal
2. Disadvantages of animal feeding method.

DISPOSAL INTO WATER BODIES
 This method is commonly used at the shores of
lakes/rivers and coasts of oceans/seas etc.
 The disadvantage is that the tides may blow the
rubbish back to the land.
 Assignment: Read and make notes about;
1. Advantages of disposal of wastes in the water
bodies.
2. Disadvantages of disposal of wastes in the water
bodies.
3. Generally what are the advantages proper waste
disposal & disadvantages of improper waste disposal

WASTE WATER TREATMENT&DISPOSAL
 Many forms of RX are available for either water
borne (sewage) or night soil.
 These include;
 Septic tanks
 Aqua privies
 Composting latrine
 Biogas plants
Definition of terms
 Scum: solid material with fats, oils, grease &soap, floating
on the surface of the septic tank or pond. Scum often
forms large floating masses called scum mats.

Waste water RX & disposal
 Sedimentation: process by which suspended solid
materials/particles in water or sewage are allowed
to settle out at the bottom of the tank or pond.
 Sewage: human excreta & waste water flushed
along a sewer pipe.
 Sewer: a pipe containing waste water or sewage
 Sewerage: system of sewer pipes
 Sludge: mixture of solids and water deposited at
the bottom of the septic tanks or ponds
 Sullage: domestic dirty water not containing excreta, also

Waste water RX & disposal
 Night soil: human excreta transported without
flush water e.g bucket method
 Desludging: removing accumulated sludge from
septic tanks
 Effluent: out flowing liquid

Sewage treatment & disposal
 A clean env’t is basic requirement of public health.
 There is need for proper removal of liquid waste
from the source as quickly as possible.
 This is done using sewerage systems leading to RX
works
 Nuisances of odour & unsightliness occur when
sewage accumulate in large amounts
 Some infections of sewage origin maybe
contracted due to bacteria, parasites & protozoa

Sewage treatment & disposal
 Untreated sewage when discharged into
river/water bodies causes following;
 Reduced dissolved oxygen level
 Spread of diseases
 Reduces self purification of the receiving water
body
 Destroys aquatic life
 The above problems are solved by sewage
treatment.

Objectives/aims of sewage RX
 To reduce pollution of the receiving water
 To use the bie products (methane as fuel gas)
effluent used for irrigation, sludge as manure
 To reduce the RX needed for receiving water body
e.g when water is supposed to be used for drinking
& other requirements
 To conform with the national water river/lake
board standards.

Types of sewage
1. Domestic sewage
 Composed of floating debris and suspended solid
matter including fats, vegetables & fibrous
materials, organic matter and gaseous liquor.
2. Industrial sewage
 Mainly composed of chemicals and a few other
substances e.g chloride from urine, carbon from
organic matter, nitrogen from proteins.
 The resulting sewage maybe acidic or alkaline

Types of sewage cont’d
3. Raw sewage
 Contains large part of organic matter & bacteria
 Bacteria are used in biological RX of sewage
 Bacteria assist in digestion coz sewage is their food
and other plants also assist in digestion of sewage.
 Types of bacteria that digest sewage
1. Aerobic bacteria: uses oxygen to digest sewage
2. Anaerobic bacteria: do not need oxygen to digest
sewage
3. Facultative bacteria: uses oxygen in compound
form

Environmental factors affecting sewage RX
1. Temperature: affects the rate of growth of bacteria
 Maybe minimal, optimum or maximum
 Organisms which are used in sewage RX require
temp of 20-45 degrees
 NB: During RX of sewage, check on temp to make
sure that optimum temp is maintained.
2. Light: in biological RX of sewage, algae and other plants
digest sewage.
 Light is essential for photosynthesis, co2 is utilized and o2
is released, in turn o2 is used by bacteria to digest sewage.
 Sunlight is used in sewage RX in oxidation ponds in
maturation.

3. PH: measure of its alkalinity or acidity or
concentration of hydrogen ions.
 Sewage is usually alkaline in PH
 The survival of organisms in sewage depends on
the correct regulation of the acidity and alkalinity
4. Moisture: very important in life
 Most active growing organisms are composed of
75-95% of water which is essential for their
metabolism. Water acts as a solvent and means of
transportation of nutrients required by all living
organisms

5. Oxygen: Needed for breakdown of organic matter
 Microorganisms derive oxygen from the media
they are suspended e.g water and organic matter.
 Oxygen is very important in the RX of sewage coz
bacteria that digest sewage utilize it to release Co2
to be used by algae
6. Toxic substances especially from industrial waste
 Inhibits metabolism of the organisms involved in
sewage RX
 Effects of toxic compounds are influenced by
factors e.g PH, salt concentration & contact time

 Toxic wastes must be treated b4 they are
discharged into any public RX plant
 Toxic substances include liquors from paper mills,
metal industries, diaries, breweries, slaughter
houses and laundries
Principles of sewage Management
1. Removal of sewage from the source and
transportation
2. Destruction of pathogen in the sewage
3. Re-use of the treated sewage

Factors considered when designing sewage RX works
1. Hygienic factors
 Pathogens should be not allowed to come into
contact with people.
 High degree of RX is required to avoid or stop
pathogens from spreading by direct contact or
through food, soil, or water.
2. Nuisance factors
 Nuisances of odour or smell must be eliminated
3. Traditional factors
 Any method for collection, transportation, RX & re-
usage must be assessed i.e religious & social factors

Factors considered when designing sewage RX works
4. Receiving water bodies
 The water body into which sewage is to be
discharged should be considered when. When the
receiving water body is down stream, extra
precautions are taken to ensure that the effluent is
of highest quality.
5. Working of the system
 Consider the maintenance and operation of the
working system, train personnel and ensure
availability of spare parts
6. Use of effluent: used for irrigation, fish farming etc
7. Resource availability

Site selection for sewage RX plant
 Proper selection of the site minimizes nuisances to
the community& its running costs e.g use of a
pump can be avoided by selecting a site where
sewage can flow gravity.
 The site should be at least 500m from the nearest
habitation to avoid mosquito, flies nuisances, smell
 Other factors to be considered include;
1. Type of soil at the site to avoid extra expenses in
lining the bottom and the sides to make it
impervious
2. Site should be free from flooding/floods
3. Site should be big enough to allow future expansion

Aims of sewage RX plants
1. Prevention of pollution of the receiving water
bodies either pathogenic organisms, organic
matter, inorganic matter or toxic substances.
2. To reduce nuisances of smell, flies, mosquitoes etc
3. To preserve aquatic life
4. To ensure self purification of the receiving waters
5. Whatever the RX design, considers all types of
sewage i.e the plants should cope with all types of
sewage.

SEWAGE WORKS
 There are two methods of disposing excreta from
towns and cities;
1. Sewage RX works/plants
2. Sewage lagoons/maturation ponds (sewage
exposure to atmosphere)
Sewage RX works/Plants
 It is central RX plant for sewage collected from
houses, towns, and cities
 It consists of the following;

Components of sewage Rx plants
1. Screening chambers
2. Grit chamber
3. Flow recorder
4. Distribution chamber
5. Sedimentation chamber/tanks
6. Sludge pump
7. Dozing chamber
8. Biological filters
9. Humus tanks
10.Sludge drying tanks/beds

HOME VISITING
 Is an act of going to homes in order to find out the
health needs and examine the env’t of different
families.
 It involves teaching family members how to care
for the sick or disabled members in the community
using family’s resources.
Main rules for home visiting
 You’re a visitor, there4 obey customary rules for
visiting a house. Even if you know the house hold,
never go inside until you have been invited in.

HOME VISITING
Main rules for home visiting cont’d
 Remember you are there to help the family
identify or solve its problems or to check up on the
health action, they promised to take.
 They have a lot of work to do, you shd not waste
their time with un-necessary talk
 Remember very many house holds you will visit
have very little basic needs, there4 use them
carefully.
 Remember don’t be too critical or else they will
not allow you to visit them again.

Purpose of home visiting
 To check on regular basis general health of the
family.
 To collect information about births, deaths that
may have occurred.
 To provide health education to families &
individuals.
 To provide information to the health center staff
on what is going on in their service area.
 To identify customs, beliefs, life styles and other factors
influencing the health of the individuals
 To trace contacts of diseases

Reasons for home visiting
 To help to start an agreed action or help encourage
family to carry out an agreed action e.g choosing a
site for latrine construction or attending ANC/MCH
 To remind mothers to take children for
immunization
 To help family to learn a specific skill with their
own resources e.g
1. How to make ORS
2. How to prepare the 1st solid food to a breast fed
baby using the foods the family can afford

Reasons for home visiting cont’d
 To find out how each family lives & whether the
place where they live is its self cause of the health
problem.
 To find out how different family members behave
and who influences what the family does including
health seeking behaviour.

Steps in carrying out a home visit
Every community is different and so is every family
especially when the health worker is new;
1. Planning (decide who to visit);
 Identify the family you would like to visit, usually
find out at risk families
 Make a list of important things to do e.g teaching,
RX, immunization, examination.
 Plan for logistics e.g books, pens, transport
 Ask family for permission to visit and get directions
to their home.

2. Implementation
 Visit families at a convenient time
 Find out from village leaders, chiefs & others
where people live and get permission
 Establish rapport and introduce your self by
greeting & showing respect& make family
comfortable.
 Invite head of the family to ask questions
 Keep all information confidential

2. Implementation cont’d
 Ask what their problems are & listen to what they
say e.g mixing ORS, position of baby during breast
feeding, feeding a sick child etc
 Look around& take note of the env’t. is thee a
latrine/toilet & is it in use, is there refuse pit,
source of water
 Talk with family members and find out about
nutritional status of the family
 Keep records of the discussions

3. Evaluation
 Using the objectives, review your home activities
and re-plan for another visit.
 Arrange for follow up visit in order to;
 Assess progress of recovery and implementation of
activities
 Arrange the date and time to visit them again
 Always follow the same approach so as not to
forget the important information
 You should begin by asking questions concerning first
about mothers, 2nd children, 3rd father & other adults, 4th
possible diseases and 5th env’t.

What to take with you on home visiting
 Take a simple first aid kit& soap, this can be very
useful for an emergency you may meet
 Take a note book to remind you, whom to see and
talk to and also note book for recording health
facts and problems
 N.B: Whenever possible visit 1st families who have
no infections in order to avoid the risk of carrying
disease from one house to another.

Activities in home visiting
1. Provide one with a focal point of how to carry out
a number of activities e.g;
2. Immunization
3. Contact tracing
4. Provision of Reproductive health services
5. Patient follow up
6. Health education on sanitation
7. Safe water provision and provision of community
based rehabilitation services.

Skills required for home visiting
1. Interviewing skills
2. Counseling skills
3. Understanding skills
4. Questioning skills
5. Convincing skills
6. Observing skills
7. Answering skills
Tools used in home visiting
1. Questionnaire
2. Interviewers' schedule
3. Checklists
4. Guide for focus group discussion

Format for tool for home visiting
1. Date……………… Time…………………………………………..
2. Village……………….. Sub-county……………………………….
3. County………………… District……………………………………
4. Head of the family…………………………………………………
5. Distance from the health unit………………………………..
6. Number of occupants……………………………………………
7. Type of house…………………… Level of education……..
8. Under fives: Sex….. Age………… D.O.B………………….
9. Immunization status……….. Nutritional status………..
10. Size of the family…….. Income/occupation……………

Format for tool for home visiting cont’d
1. What kind of activities do family members engage in to
earn a living………………………………………………………………………
2. Is the income regular or irregular………………………………………
3. Who decided how money is spent……………………………………
4. Family planning: Type… Side effects..... Effectiveness……..
5. Housing: Type…. Walls……Verandah………………………………….
Windows…… Ventilation……… Roofing…………………………………
6. Environmental sanitation: Source of water………………………..
How much used per day……..... How far water source…………….
Pit latrine & its condition……………. Animal house…………………..
Compound… Refuse disposal…………………………………………………
Food/nutrition: staple food…... How much food is sold………….

ENVIRONMENTAL HEALTH SURVEY
 It is a special field study done to find out
information on env’tal factors that affect health of
the community. It includes;
1. Housing
 Type of house (permanent/temporally/semi
permanent)
 Number of people in the house hold
 Ventilation and number of ventilators
2. Water source
 Protected water sources e.g protected springs, bore hole,
storage tanks (roof catchment), lakes, rivers

3. Sanitation
 Type of excreta disposal e.g pit latrine
 Method of refuse disposal
4. Food
 Type of staple foods available
 Availability of sources of animal protein
 Food storage
5. Domestic animals
 Type of animals kept and their residency inrelation
to the living house

 Env’tal health survey also includes;
1. Silent survey/5Ls (Look, listen, learn, lye, low)
2. Market survey
3. School health survey
 Why an env’tal health survey should be done?
 It is carried out to find out KAP of the community
regarding their health awareness about the need
to provide and use of pit latrine can be
determined. If the community has latrines, how do
they feel about them.

1. Planning and organizing an env’tal health survey.
2. Mobilize material required e.g 5Ms (money,
materials, man power, management, moment)
3. Formulate objectives of the survey
4. Consult local people and cooperate with them
5. Visit the area to be surveyed and obtain
information about their culture i.e 5Ls
6. Decide on the methodology to be used i.e choose
appropriate data collection techniques and tools
7. Ensure that there is enough staff and other
resources to conduct the survey.

Survey methodology
 There must be a method of collecting data from
the community
 The usual way is to ask set of standardized
questions
 A set of standardized qsns in a survey is called a
questionnaire or interviewer‘s schedule, checklist
 It is a necessary tool for collecting information e.g
qsns that can be asked include;
 How many people are in the household?
 How many adults are in the household?
 Do you have latrine, water source

Survey methodology
 Preparing a questionnaire
 Points to remember
1. No of qsns shd not be too many or else they will
bore the respondent
2. The type of qsns shd be either close or open ended
qsns. Qsns shd be phrased/set in such away that
shd not arouse resentment or annoyance
 Open ended qsns; allows respondent to express
himself/no limitations
 Close ended qsns; have limited options e.g yes/no
or particular answers

Survey methodology
3. Interviewers must be trained well to avoid mistakes
that may arise
4. Pretesting the questionnaires to find out
completeness and purposes of availability (tools
give intended data), reliability (would the tool give
similar data for different population groups)
5. All qsns must be prepared b4 being used and
pretested. This is to eliminate un clear qsns which
may lead to wrong information

Survey methodology
 An open ended qsn; one which requires a
respondent to give an opnion. It gives him/her a a
liberty to answer in away he/she feels is correct e.g
what methods of refuse disposal shd be
recommended at HCIV
 The same qsn can be asked in a close ended way;
which of the following methods of refuse disposal
would you recommend for HCIV?
 A) Refuse pit B) Open dumping C) Controlled tipping
D) Direct incineration

Definition of some terms
1. Home stead; collection of homes in a small place
for relatives
2. Household; one house in a place without relatives
3. Pilot study/feasibility study; intervention/program
on a small scale once it is successful then
implement it in a whole community /country.
N.B: Checklist for village environmental
survey=reference community health book.

OCCUPATIONAL HEALTH&SAFETY
 Safety; absence of conditions which may result
into ill health
 Occupation; engagement for which a person gets
pay or reward
 Occupation health; broad discipline concerned
with the interaction between health and work or
concerns industrial hygiene, preservation of health
of workers and prosperity of worker’s families on
non occupational as well as occupational
influences of workers’ health.
 Occupational health hazards:

OCCUPATIONAL HEALTH&SAFETY
 Effects of industrialization on workers’ health
 Hazards of occupational diseases
 Adverse effects of excessively long working hours
 Less attention to safety devices when dealing with
machines resulting into accidents
 Exposure to toxic hazards.

Activities of occupational health
 Recognition& identification of health hazards by
occupational health staff e.g dust, gas, vapor,
noise, x-rays, infections, accidents
 Measurement of hazards e.g sound meter for
noise, Geiger counter for radiations, hygrometer
for humidity, kata thermometer for air velocity,
globe thermometer for radiant temperature.
 Monitoring & evaluation of hazards e.g biological
or environmental hazards and complying with
standards
 Management of those affected e.g first aid kits,
compensation policy in place

Sources/types of occupational hazards
 Vary from location to location, type of equipment,
chemicals or duration of exposure
 Classified basing on how they occur
1. Chemical hazards e.g gases (Sulphur, nitrogen), liquids
(DDT, pesticides, cyanides), solids (dust, asbestos, lead).
2. Physical hazards e.g noise& vibrations, radiations, light,
electricity, extreme temperatures (low/high)
3. Biological hazards e.g HIV, Hep B, Anthrax, TB, Bilharzia,
Brucellosis, cotton dust
4. Climatic hazards e.g floods, tsunamis/strong winds, sun
5. Psychosocial e.g rural urban migration, malnutrition,
disruption of culture, fatigue, stress

Prevention of occupation hazards
1. Change from more dangerous to less dangerous
activities/occupation
2. Separate (separate workers according to likelyhod
of hazards e.g less dangerous/medium/severe. In
medical its called segregation of medical waste.
3. Ventilate (recirculation of air in a work place)
4. Education of workers about prevention and control
of health hazards
5. Protect (protective garments e.g overalls, gloves,
masks, respirators, goggles, helmets, safety boots.
Noise=decibels(db) more than 90db=hearing loss.

HOUSING AND HEALTH
 Housing affects health in number of ways
 It should be designed to prevent transmission of
diseases
 A house that is too small& over loaded will bring
people together in continual close contact
 A house shd have a good arrangement for washing
hands b4 meals and after visiting a latrine
 Shd be designed so that it is easy to clean and tidy

Important requirements for health housing
1. Adequate and safe water supply. The water supply
shd be satisfactory in quantities, quality and
reliability
2. Sanitary excreta disposal and adequate surface
water drainage. Space btn latrine& dwelling house
& kitchen shd be 10-15m(30-50ft)
3. Solid waste management. There shd be adequate
method of refuse disposal i.e burning, burying, or
composting. Domestic cleanliness& cleanliness of
the surrounding shd be emphasized.
4. Adequacy of structurally acceptable shelter

5. Food hygiene& preparation. There shd be separate
rooms for food storage and preparation.
6. Protection against air pollution, thermal hazards
and excessive noise.
7. Adequate light and ventilation
8. Adequate habitat siting. It shd be built on a good
site which is dry and not subjected to flooding.
9. Access to community services e.g schools,
hospitals, roads etc
10. Meeting special needs for elderly, handicapped
etc

11. Separate accommodation for humans and animals
12. Shd have hard floor and walls preferably made of
concrete and plastered/smoothened.
In many places, mad burnt bricks are an appropriate
way of improving houses, stores, latrines etc.

Interaction btn housing & health
These are many/numerous but a few areas of major
concern will be discussed;
1. Location.
It can have important effects on health of inhabitants.
This is particularly relevant to vector borne
diseases e.g malaria, sleeping sickness where
housing built closes to high vector concentrations
may increase disease transmission
2. House design& location can promote/hinder
domestic hygiene. This can occur especially for
FORT and water washed infections

3. Housing & airborne infections e.g measles,
mumps, meningitis. Housing design will affect
crowding, ventilation, temperature, humidity, all of
which will affect transmission of air borne
pathogens. A smoke filled atmosphere will also
influence the susceptibility of individuals to
respiratory infections. However its not normally
possible to demonstrate an association btn large
better ventilation rooms and better health.
Its clear that over crowding & close physical contact present
many opportunities for transmission of air borne
infections, also many events outside the house can do the

4. Manner in which house promotes or discourages
population of rats, insects or domestic animals will
influence prevalence of all infections related to
them e.g in Latin America poor housing
encourages infestation with bugs that are vectors
for chagga’s disease.
In general any house in which people share
animals/poultry may assist the transmission of
diseases carried by these animals& their parasites
5. Certain details of a house design can have an
important influence on diseases transmitted by
night biting mosquitoes.

5. A false ceiling or mosquito nets across the eave
(space btn walls& roof) can be a very effective
improvement as this is where mosquitoes often
enter. Special attention shd be paid to windows
including inexpensive buglar proofing, screening
windows and ventilators to prevent entry of
mosquitoes and other vectors/insects.
6. Earth floors in houses can harbor eggs& larvae of
intestinal worms (hook worms). These are also
conducive to parasitic insects e.g blood sucking floor
maggots (Auchmeromyia Luteola) and sand fleas (jiggers
or Tunga penetrans) both are widely spread in Africa.

VENTILATION
 Air must be adequate in quality and quantity for
good health to maintain sufficient pure air indoors.
 Adequate natural and artificial ventilation must be
provided
 The total area of all ventilation aperture should
not be less 20% of the total floor area.
Reasons for ventilation
1. To provide 02 & prevent high concn of CO2
2. Regulation & maintenance of heat balance
3. To help prevent concn of bacteria carrying particles, this
reduces the infection pressure to low level

Reasons for ventilation cont’d
 Infection pressure: is measured by the number of
infectious particles of bacteria or viruses in the
environment.
 For example if there are 2 qden in the house who
both have measles, the infection pressure will be
greater than if there was one child with measles.
4. It removes body odours & products of combustion
e.g smoke from a fire place
5. It helps to meet occupants respiratory body
requirements.

Types of Ventilation
1. Natural ventilation
 This constitutes ventilation openings which are
actual openable part of the windows or any hinged
panels, adjustable louvers or other objects which
open directly to external air.
 For correct orientation& cross ventilation, over
hang eaves and perforated walls provide
satisfactory micro climatic conditions within a
room but if found insufficient, this should be
augmented/enhanced with roof ventilation.

2. Artificial ventilation
 This is mechanical ventilation adapted to any
condition
 It may include an extraction system (vacuum
system) and input system (propulsion) or balanced
system consisting of both extraction and in put
system.
 Air conditioning; refers to a technique in which air
is filtered, washed, dried or humidified and
warmed, cooled and distributed.

2. Artificial ventilation cont’d
 It is recommended that in living rooms& bedrooms
each person should be supplied with at least 17m3
of air/hour
 Rooms must have regular air change/circulation to
avoid discomfort of occupants.
 Contaminated air could lead to headache,
sweating and giddiness/dizziness/faintness.

LIGHTING
 Natural lighting is an essential design of a building
 Good quality of light depend on variation btn light
and darkness (contrast)
 Good quality light helps occupants see and
recognize objects with minimum eye strain
 The better the light, the easier the work
 Light must be agreeable and without sharp
shadows which can cause eye fatigue.
 Building codes require that any house fit for human
habitation must have adequate natural lighting for each
habitable room & working areas including kitchen.

Importance of lighting
 Visibility, protection of eye sight and prevention of
eyes from straining.
 It prevents accidents
 It assists in cleanliness
 It increases workout put and economic gain since
workers can be precise and in good health.

DAY LIGHT
 Natural lighting of a room depends not only on the
window size and shape but on orientation/direction,
adequacy of day light, obstruction and decoration
 Max day light is obtained in a room when the largest
possible area of the floor and walls receive light directly
from the sun/sky
 The extent to which the room is lighted directly depends
on sky light available i.e amount of floor & walls surface in
the room which is in direct line with & open to the sky or
from which the sky is visible
 The direct light falling on a given point in a room depends
largely on the aperture i.e the actual amount of sky visible
from that point.

ARTIFICIAL LIGHT
 Sources; firewood, electricity, kerosene, gas
 Some public health laws require that any house fit
for human habitation must have adequate source
for artficial lighting e.g gas, electricity, or by other
means in each room, stair case passages etc.

Community vector, rodents/pests control
 Insects and animals (rodents) spread some
diseases commonly in rural areas
 There are national and international programs for
control of vectors e.g tsetese fly control, malaria
control programs etc
 There should be steps which
individuals/neigbors/village /community can take
to reduce the health hazards associated with
rodents & vectors

Community vector, rodents/pests control
 Vectors: organisms which transmit/carry diseases
causing pathogens.
 They maybe biological carriers e.g mosquitoes,
tsetse flies (true vectors =part of the life cycle of
the causative agents takes place in the vector)
 They maybe mechanical carriers e.g house
flies(musca domestica), cockroaches (periplanata
americana)

Public health importance of vectors & rodents
 They suck blood e.g mosquitoes
 They are a nuisance to persons, cause discomfort
due to their bites or stings
 They destroy food e.g rats
 The contaminate food or drinking water by their
dropping
 Toxicity due to chemical used to control them
(organophosphate poisoning)
 Economic loss, cause disease which have to be
treated & there is expenditure on their control
 Damage to houses, furniture, crops e.g rats

General control measures
 Establish the type of vector/rodent
 Place of resting
 Time of feeding
 Breeding sites
 Seasonality
 Foculity ( areas usually they come to) are they in a
defined place or they are scattered.

The design of control measures
1. Use of environmental sanitation
 Proper solid/refuse waste mgt
 Proper waste water mgt
 Proper disposal of human excreta and animal dung
 Mgt of bushes around homes
 Proper housing sanitation and design
 Personal hygiene
2. Involvement and participation of community
 Sensitize people and engage them in control
measures.

The design of control measures
3. Destroy and kill vectors/rodents
 By biological control e.g use of predators of certain
vectors e.g for snails, mosquitoes, certain fish
introduced in the water bodies to eat them.
 By high temps e.g lice for beddings and clothing
 Mechanical means e.g traps for rats, tsetse fly etc
 Use of chemicals e.g rodenticides for rats or
fumigation (spraying powder), insecticides like non
residual e.g pyrethrum which kills immediately
 Residual insecticides e.g DDT (Dichloro Diphenyl
Trichloro Ethane, Larvicides,molluscides-snails

House flies (Musca domestica)
Habits
 Breed and feed on decaying matter or any filth
such as vegetable refuse, manure, animal
carcasses and particularly on feaces.
 They transfer bacteria from decaying matter or
filth on to human food, skin, eyes when they land
on them.
 Flies around people are looking for food which
maybe scraps, discharges from eyes and wounds,
food around mouth of children or feaces

House flies (Musca domestica)
 Its most objectionable and dangerous habit is that
having filled its crop with all kinds of micro
organisms or germs, it may then land on food and
then ejects the contents of its to crop to refill with
food more of its liking leaving a patch of deadly
germs/pathogens
 The public/village committee members should be
taught about these fly habits so as to understand
how to control them.

SOURCES OF WATER
 Rain water
 Surface water or ground water
 Under ground water
Rain water
 This is the purest if collected & stored in clean
enclosed tanks.
 It may also pick impurities from atmosphere, roofs,
gutters and storage tanks
 Its hard to collect from grass thatched roofs
 Large tanks are required to store significant
amount of water to last in a dry season

SOURCES OF WATER CONT’D
 Rain water is soft and doesn't contain any essential
mineral slats.
 It may not also taste very good
 It is seasonal and not reliable
Surface water
 This is the H2O above the 1st layer of impervious
rock. This impermeable layer maybe quite near or
quite deep down
 If it emerges by its self, its a spring and if you have to dig
to reach it, its a well & with a machine a hole maybe
bored through impervious layer, its a bore hole.

Advantages of surface Water
 H20 in lakes, rivers, ponds, seas, oceans, springs,
shallow well, is the commonest source of water.
 It is easily accessible, can be obtained by hand or
simple pumps
 The larger lakes & rivers are permanent all the year
around
Disadvantages of surface water
 Can easily be polluted by direct contamination by
man & animals or indirectly when rain washes
feaces & other pollutants from the banks, to
streams, water holes etc (surface run off/storm

Disadvantages of surface Water cont’d
 Can be contaminated by chemicals used in
agriculture & industry (attempts must be made to
prevent and also to purify it b4 use)
 Surface H20 can also be upland surface H20 which
flows on high hills, H20 that collects into streams
above where people live is often plentiful, clean
and make good drinking water
 Can be piped to people living lower/down hills by
gravity. However , this source must be protected
from grazing animals & human settlement in the
catchment area

UNDERGROUND WATER
 As the H20 soaks through the ground & travels
under ground, it is filtered as soil is a good filter
media.
 Advantages of underground water
 clean., plentiful and permanent
 Doesn’t depend on local rains
 Many rural areas and small towns use this type of
H20 e.g deep wells (bore holes), deep springs.
 Its quality depends on geological formation and
modes of collection.

Disadvantages of underground H20
 Water usually has a lot of dissolved salts and other
minerals making it salty.
 Some times its too salty or hard and removing
these salts is very expensive process
 Requires pumping from great depth before
reaching the user.

Sources of water contamination
 It is easier to prevent water from getting dirty than
it is to clean it. There are various possible sources
of pollution/contamination btn the time water falls
as rain and the time it is used.
 Collecting surface of rain water may have leaves,
insects, birds and animals feaces on them.
 Water running over the earth may become
contaminated with human/animal excreta,
chemicals from gardens, heaps of refuse/solid
waste, fertilizers or industrial wastes through
direct or indirect means e.g discharging waste
water directly into water body or indirectly by

 This contamination is less high up on mountains
and greater near towns down wards.
 Shallow wells may also be contaminated by excreta
and refuse being washed into them especially if
latrines are nearby. Wells may also be
contaminated by use of dirty containers for
drawing water or by oil from a pump.
 Bathing and urinating or even defecating in H20
 Piped water maybe contaminated from leaks in the
pipes especially if the pass near foul water or dirty
drains.

 Seepage from the surface may enter through the
top few meters of the well lining if it is not
sufficiently water tight near the surface
 Rubbish thrown near or into the well. The chance
of this may be prevented/reduced by preventing
children from playing near the well but the only
certain way to prevent this is to fit a permanent
cover on the well and install a pump.
 Spilt water. If the there is no head wall or people
stand on the head wall to draw water, H20 which
has splashed against their feet can fall back into
the well

 Water may go bad if stored for too long in closed
container
 Water from any source may become contaminated
if it is drunk from dirty or communal drinking
vessels
 Wind blown refuse and other decomposing
organic mater will decompose the water
 Dead animals e.g cats, dogs, man can also
contaminate water

Rural water supply (RWS)
 This aims at the least sophisticated system that will
give the desired level of service of H20 supply i.e;
 Water supply that is of quality (both chemical&
biological) and quantity/adequate.
 Coverage i.e population to be served, aim at
covering large area
 Proportion of public stand pipes to house
connections
 Basic levels (lower) are to be accepted
 International standards to be relaxed coz its difficult to
maintain them at all times. Demand may increase as the
level of services increase

Standards for materials in RWS
 Use of local materials is advisable
 Lower standards (cheap but not poor)
 Operation and maintenance should be community
responsibility
 If you have to import materials, the import should
be from other developing countries.
Source selection
 Survey the source for feasibility
 Consider the yield & seasonal variations of the
yield

Water purification
Can be achieved by a single or combination of some
of the following measures;
 Protection of water sources
 Storage
 Coagulation and sedimentation
 Filtration
 Disinfection (chemicals like chlorine)
 Boiling

RX of Water on small scale
Objectives for H20 RX/reasons
 To remove pathogenic organisms
 To remove substances which impart colour, taste
or odour to the H20
 To remove excess or undesirable minerals and
chemicals
 To regulate essential elements or chemicals which
may be in excess or lacking
 To remove excess or undesirable dissolved gases
 There are various methods of H20 RX on small
scale and following methods are commonly used;

1. Boiling/heating
 It is easiest & fastest reliable way/method to
sterilize H20/disinfect H20 on a small scale.
 Water should be brought to a boiling point and
kept boiling for 15-20 minutes.
 This destroys all forms of microorganisms including
most resistant spores or cysts.
 Boiling is effective to all kinds of raw water
 It is practical unless there is lack of fuel
 It doesn’t require a technical skill, any family can
apply this method.

Disadvantages of Boiling/heating
 Boiled water has a flat taste due to loss of
dissolved gasses during the process of boiling
 Greater care must b taken to avoid re-
contamination of boiled water during storage or
consumption
 It must be kept in a clean and firmly covered
containers, preferably in the same container used
to boil
 Containers with taps at the bottom can be used safely in
storing H20. Because tea is made with boiling water, weak
tea is an excellent safe drinking water for small children.

2. Chlorination (chemical method)
 Can be used to disinfect water on a small scale but
care must be taken to avoid over chlorination.
 Chlorine is an oxidizing agent and if added to
impure water H20, it will immediately oxidize the
impurities and no longer be available for
disinfection.
 It therefore essential that Cl2 dose should be
greater than the required to satisfy the immediate
Cl2 demand. This demand will vary depending on
the quality of water.

2. Chlorination (chemical method) cont’d
 In case of piped water, if an adequate dose is used
to satisfy the Cl2 demand, a residual Cl2 is added
to provide protection against contamination during
subsequent distribution of water.
 A given Cl2 dose is far more effective in destroying
bacteria and viruses in H20 if the PH is low.
 Chlorine is also considerably more effective at
warm temps.

Application of Cl2
 It needs at-least 30 min in contact with water to
disinfect it
 It is therefore applied before H20 enters the
storage tank, so that it can take effect during
storage.
 2-3 drops of 1% Cl2 in a liter of H20 can provide a
reasonable or satisfactory sterilization
 The dosage can be doubled if the H20 is too cloudy.
 The chlorinated H20 shouldn’t be exposed to sunlight
after dosing at that would remove the protective residue.

Application of Cl2
 Other factors which affect the disinfecting power
of CL2 include;
 Quality of water being disinfected
 Contact time
 Temperature
 Low PH
 Presence of NH4 in H20 being disinfected
 Cl2 can be inform of gas, solution , powder, tablets

3. Iodination (chemical method)
 Iodine and its compounds can be used effectively
for water disinfection
 It is believed to be a better disinfection than CL2
 It can be obtained as 2 % tincture of iodine and
tablets of I2 are available on market.
 Application of iodination
 Tincture of iodine applied at a rate of 2 drops/liter
gives satisfactory results
 Disadvantages: relatively expensive and causes
H20 to have a medicinal odour of iodine

RX of H20 on small scale-Storage method
1. Three pot system
 If H20 is allowed to stand, many harmful organisms
which maybe in it die coz they can’t survive in H20
for a long time e.g if H20 is stored for at least 48
hrs, any schistosome cercariae in it will become
non infective.
 Much of the suspended matter also settles at the
bottom, H20 cleansing by storage can be simply
done in a home by using three pots.
 Two of the pots should be large& used for fetching
H20 on alternative days

1. Three pot system cont’d
 The 1st pot should be allowed to stand for 24 hrs,
H20 on top becomes clear and should be carefully
put into another smaller pot for drinking and the
remaining water at the bottom for washing.
 When the 1st pot is empty, it is cleaned and filled
and allowed to stand for 24hrs
 The 2nd big pot is used in the same way as the 1st
big pot. In this way each day’s water is allowed to
stand for 24hrs before it being used.
 H20 stored on large scale shd stand for 3-7days b4 being
used

1. Three pot system cont’d
 There are other various ways of storing water in
rural areas where there is no piped water
 It maybe stored in transport containers e.g tins or
jerry cans which are kept in designated area of the
house easily accessible to remembers.
 Where storage containers are big, a receptacle
such a s a glass or cup is kept nearby for the
purpose of drawing water for drinking
 Containers should be covered to avoid
contamination of water.

1. Diagram showing three pot system

Ways in which domestic H20 gets
contaminated
 Use of dirty containers for fetching water
 Use of contaminated containers or covers such as
leaves
 Dirty contaminated containers used for storing
water at house hold level
 Contamination of drinking water by domestic
animals such as poultry and dogs
 Objects falling into the uncovered storage receptacle
 Dirty hands of people drawing drinking water
 Over storage, if water is stored for a long time it can
become stale

2. FILTRATION
 For house hold, water can be done using two
methods;
1. A home made sand filter
2. A ceramic candle filter

Sand filtration
 This can be set up in individual homes by use of
large container e.g a drum or water jar.
 The components& basic principles of operation are
the same as those of slow sand filter.
 The min depth of filter sand shd not be < 60cm
 A carefully designed filter can remove most of
substances that cause taste/odour
 If used in combination with CL2, home made filters
are quite effective.

Limitations of sand filter/disadvantages
 They cant be relied upon to remove all pathogenic
organisms especially viruses and small bacteria
 The filter frequently gets clogged 9blocked)
especially if raw water being filtered is dirty
 The filter media needs continuous flow of water
and the rate of filtration should be controlled not
more than 2 liters per minute
 The top layer should scrapped, cleaned and
replaced at fixed intervals.

Large scale sand filter
 The commonest large scale filter is made of
different grades of sand arranged in layers with
stones at the bottom, the coarse sand and fine
sand on top.
 Sand filter for public water supply are usually built
in containers/tanks

Diagram of home made sand filter

Ceramic candle filter
 These are available commercially for filtering
domestic water
 The core of the filter is a porous cylinder made of
pottery in shape of a big candle and hence the
name.
 It has 2 containers, the top container has a
removable lid, holds the candle(s) and receives raw
water to be filtered
 The bottom container receives the filtered water
and has a tap

Ceramic candle filter cont’d
 Water is put into the top container, filters through
the pottery candle/clay.
 The pottery candle is made from high quality
unglazed ceramic porcelain and it is received and
stored in the bottom container.
 The efficiency of filtration depends upon the pore
size of the candle which vary depending on
manufacturer.

ENVIRONMENTAL HEALTH(0).ppt

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