Environment - Solid Waste and Excreta Disposal

Environment
SOLID WASTE MANAGEMENT AND EXCRETA DISPOSAL
Kuldeep Vyas
Asst. Prof Community 1Kuldeep Vyas M.Sc. CHN

MANAGEMENT
OF
SOLID WASTE
2Kuldeep Vyas M.Sc. CHN

Solid waste
• Garbage (food waste)
• Rubbish (paper, plastic, wood, glass etc.)
• Demolition products (bricks, masonry)
• Sewage treatment residue (sludge & solids)
• Dead animals
• Manure & other discarded material
 Strictly speaking it should not contain night soil
 The per capita daily production is 0.25 to 2.5 kg

Solid waste-health hazards
• On accumulation it decomposes & favors fly breeding
• Attracts rodents & vermin
• Pathogens present in waste may be conveyed back to man’s food through flies & dust
• Possibility of water & soil pollution
• Unsightly appearance
• Nuisance from bad odours
There is a correlation between improper disposal of solid wastes & incidence of
vector borne diseases 4Kuldeep Vyas M.Sc. CHN

Sources of solid waste
Domestic Refuse
Industrial refuse
Ash
Rubbish
Garbage

Street refuse
Leaves, straw, paper
Market refuse
Putrid vegetable & animal matter
Stable litter
Animal droppings, left over animal feeds

Solid waste-storage
• First consideration is to proper storage of refuse while awaiting collection
• The galvanized steel dust bin with close fitting cover is a suitable for storing
• The output of refuse per capita per day in india is estimated to vary from 1/10-1/20c.Ft.
For a family of 5 members
• The public bins in India are without cover
• They are placed on concrete platform raised 2-3 inches above ground level to prevent
flood water entering the bins

Storage
Public bins Paper sacs
Galvanized steel
dustbins
Household

Collection
House to house collection
Rag pickers
Refuse collection vehicles
• Open type
• Enclosed

Methods of disposal
• Dumping
• Controlled tipping or sanitary land fill
• Incineration
• Composting
• Manure pits
• Burial

Dumping
Method of disposal in low lying areas
Partly as method of reclamation of
land
Mainly as method of disposal of dry
refuse
Drawbacks
Exposure to flies and rodents
Unsightly appearance and bad odour
Dispersion by action of wind
Pollution of surface and ground water

Controlled tipping/ sanitary landfill
Methods in operation
1. Trench method
2. Ramp method
3. Area method diffuse quarries, clay
-Level ground
-Moderately sloping terrain
-Filling land depressions,
pits
Most satisfactory method of disposal where suitable land is
available
Material is placed in a prepared area and covered with earth
at the end of working day
Takes 4-6months for complete decomposition by chemical,
physical, bacteriological changes

Mechanism
• Chemical, bacteriological & physical changes occur in buried refuse
• Temp. Raises to 600. C in 7 days & kills all the pathogens and hastens
decomposition
• Cools down in 2-3 weeks
• Complete decomposition to an innocuous mass takes place by 4-6 months
• This method has been revolutionized by mechanization. The bull dozer achieves
the tasks of spreading trimming and spreading top soil

Incineration
It is hygienic method of disposal of refuse
Method of choice where suitable land is not available
Most suitable for hospital waste
Not a popular method in india because the refuse
contains a fair proportion of fine ash which makes
burning difficult
Drawbacks
Heavy outlay and expenditure
Manipulative difficulties
Loss to community in terms of much
needed manure 15Kuldeep Vyas M.Sc. CHN

Composting
Combined disposal of refuse and night soil or sludge
Organic matter Manure/humusBacteriological
action
Prinicipal by-products are carbondioxide, water, heat
Heat produced is >60deg over days destroys eggs, larvae of flies, weed seeds and
pathogenic agents
The end product-few or no disease producing organisms & is good soil builder

Composting
Methods
Bangalore method (anaerobic/hot fermentation method)
Mechanical composting (aerobic method)
Bangalore method
Refuse(15cm)
Night soil(5cm)
Refuse
Night soil
Refuse
Earth
(25cm)

Mechanicalcomposting
In this compost is manufactured on large scale by processing raw materials and turning
out a finished product
Refuse is cleared of salvagable materials
Pulverisation
Mixed with sewage, sludge or nightsoil in rotating machine
Incubated for 4-6weeks
In vogue in some developed countries
In india, govt is considering the installation of these plants in cities like delhi, hyd,
mumbai, chennai etc.,

Composting: some benefits
Compost allows the soil to retain more plant nutrients over a longer period.
It supplies part of the 16 essential elements needed by the plants.
It helps reduce the adverse effects of excessive alkalinity, acidity, or
the excessive use of chemical fertilizer.
It makes soil easier to cultivate.
It helps keep the soil cool in summer and warm in winter.
It aids in preventing soil erosion by keeping the soil covered.
It helps in controlling the growth of weeds in the garden.

Manure pits
• Method of refusal in rural area by individual householders
• The garbage, cattle dung, straw and leaves are dumped into the manure
pits and covered with earth after each day
• In 5-6 months of time refuse is converted into manure which can be
returned to fields
• Two such pits are created, when one is closed the other will be in use

Burial
• Suitable for small camps
• A trench 1.5m wide and 2m deep is excavated,
and at end of each day the refuse is covered with 20-30cm of earth
• When level in the in the trench is 40 cms above the ground level, the
trench is filled with earth and compacted, and new trench is dug out
• The contents may be taken out after 4-6months and used
on fields 21Kuldeep Vyas M.Sc. CHN

• Do wait until you reach a waste bin to dispose of your litter.
• Do dispose of your garbage appropriately. Put garbage out in
secure containers for the appropriate collection only.
• Do empty away stagnant water that may accumulate in
your garbage bin and reduce the risk of dengue fever and other
disease
Do’s of solid waste

• Do place only manageable amounts of garbage out in sturdy bags or
bins.
• Do wrap broken objects in newspaper before disposing of them in the
garbage to avoid injury to yourself and others including waste collection
staff.
• Do ensure that bags are securely tied and that waste is completely
covered inside of the bin.
Do’s of solid waste

• Do not litter. If we drop litter it will encourage others to litter.
• Do not put out garbage too early, especially garbage that contains meat and fish
scraps.
• Do not dump or litter illegally at the sides of the roads or in gullies, it is not only
unsightly but dangerous and hazardous to health.
• Do not allow water to collect in your garbage bin.
Dont’s of solid waste

• Do not throw broken objects (e.g. Glass, ceramic, etc.) Into the garbage without wrapping
them first.
• Do not overload your garbage bags; they may burst as a result of excessive weight or
bulk.
• Do not place needles and syringes in the garbage or leave them lying around.
• Do not compact waste in the waste bin. This makes it difficult to extract the waste.
Dont’s of solid waste

Excreta disposal

Public Health Importance
Human excreta is a source of infection
Important cause of environment pollution
Responsibility of society to dispose it safely
Failure to dispose safely leads to severe threat to public health

Health hazards
Improper excreta disposal causes
Soil pollution
Water pollution
Contamination of foods
Propagation of flies
Burden to community in terms of sickness, mortality & low
expectation of life
Deterrent to social & economic progress 28Kuldeep Vyas M.Sc. CHN

Diseases-improper disposal
Bacterial: typhoid, dysenteries
Viral: hepatitis, diarrhoeas
Helminths: hook worm, ascariasis

Extent of problem-India
74% of population is rural and majority of them go to fields for
defecation
Situation in urban area is equally worse
The solution to the problem is only through hygienic disposal of
human excreta which is a corner stone of all public health services

HOW THE DISEASE IS CARRIED FROM EXCRETA
FAECES
FINGERS
FLUID/WATER
FLIES
FIELD/SOIL
FOOD NEW HOST

Transmission of diseases to the human host is prevented by
segregation of faeces, protection of food, personal hygiene,
control of flies.
Transmission of faecal born diseases

FAECES
FINGERS
WATER
FLIES
SOIL
FOOD
PROTECTED HOST
S
A
N
I
T
A
T
I
O
N
B
A
R
R
I
E
R
Sanitation barrier –
Transmission of faecal-borne diseases

SANITATION BARRIER
Segregation of excreta by imposing a barrier is called Sanitation
barrier. This is the most effective step so that the disease agent
can not reach the new host directly or indirectly

METHODS OF EXCRETA DISPOSAL
Unsewered Areas Sewered Areas

Unsewered Areas
I) Service type (conservative)
II) Non service type (sanitary latrine)
1. Bore hole latrine
2. Dug well or pit latrine
3. Water-seal type of latrines
a) PRAI
b) RCA
c) SULABH
4. Septic tank
5. Aqua privy
III) Latrine suitable for camps & temporary use
• Shallow trench/deep trench/pit/bore hole latrines

I) SERVICE TYPE
Night soil is collected from pail or bucket type of latrines by
human agency, and later disposed by burying or
composting.

DRAWBACKS
Water pollution
Soil pollution
Access to flies
Corrosion of buckets and pans
Recruitment of staff is difficult (UNETHICAL), should be replaced
by sanitary latrine

II) Non- Service type/ Sanitarylatrines
Criteria-
Excreta should not contaminate the ground or surface water
Excreta should not pollute the soil
Excreta should not be accessible to flies, rodents, animals & other
vehicles of transmission
Excreta should not create a nuisance due to odour or unsightly
appearance

1.Borehole latrine
Forerunner of the non-service type of latrine
First introduced by Rockefeller foundation during 1930’s in campaigns of
hookworm control
It consists of a circular hole of 30 to 40 cm diameter and 4 to 8 m depth
Special equipment Auger is used

Contd.
The hole is lined with bamboo matting or earthen ware rings to prevent
caving of soil.
A concrete squatting plate with a central opening and foot rests paced
over the hole and an enclosure for privacy
It serves for a family per year
Night soil under goes anaerobic digestion.

Contd.
MERITS
No need for sweeper for daily removal.
DEMERITS
Small capacity
Auger may not be available
If the soil is loose it becomes difficult to dig

2.DUGWELL LATRINE/ PIT LATRINE
Introduced first in Singur in West Bengal in 1949-50
It is an improved Bore hole latrine
It is a circular pit of 75 cm diameter and 3 to 3.5
depth lined by pottery rings.
A squatting plate at the top with a super structure

Contd.
MERITS
No need of auger
Greater capacity
Last for 5 years per family

3. WATER SEAL LATRINES
It has water seal which prevent access to flies
and escape of odour.
Modifications of water seal latrines
a) P.R.A.I evolved by planning research and action institute Lucknow.
b)R.C.A. type by research cum action projects in environmental sanitation
of ministry of health.
Direct type
Indirect
Type

of
LOCATION: It should be away from source of water supply to prevent contamination.
SQUATTING PLATE or SLAB: It is made up of an impervious material to keep it clean
and dry. So that it will not facilitate the
growth of hook warm larva.
Dimensions 90 cms square,
5cms thickness, slop ½ inch for drainage
water with footrests.
RCA Latrine (more popular)

Pan: Receives the night soil, urine and wash water. The length of pan is
42.5cm. The width of the front portion of the pan has a minimum of 12.5cm
and the width at widest portion is 20cm. There is a uniform slope from front
to back of the pan and the pan is given a smooth finish

Trap: the trap is a bent pipe, about 7.5cm in diameter and is connected with
the pan. It holds water and provides the necessary water seal
the water seal provides the access by flies and suppresses the nuisance
from smell
2cm

Connecting pipe: when the pit is dug, away from the squat plate, the trap is
connected to the pit by a short length of connecting pipe 7.5cm in diameter
and at least 1m in length with a bend at the end
it is used in indirect type and the advantage with this is that when the pit fills
up, a second pit can be put into operation

1
2
3
4
5
Indirect Type 52Kuldeep Vyas M.Sc. CHN

Dug well: 75 cm in diameter, 3-3.5m deep
Superstructure: Attractive superstructure
Maintenance: Proper maintenance involves health education of the
people which is very necessary for the success of any sanitation related
programme

Comparison of Direct and Indirect type Water Seal Latrines
Direct type Indirect type
• Pit is below the squatting plate
• Best for areas with hard ground
• Cheaper
• Easy construction
• Occupies less space
• Pit is away from the squatting plate
• When the pit is full, direction of
connecting pipe can be changed to
another pit
• Preferred over direct type

c) Sulabh Shauchalya
Low cost water-seal type latrine by Patna based firm. 5Rs/use charged 55Kuldeep Vyas M.Sc. CHN

It is a water tight masonry tank used for individual dwelling, small
groups of houses and institutions.
DESIGN: Single chambered or double chambered.
CAPACITY: 20 to 30 gallons per person for household with a
minimum of 500 gallons.
4.SEPTIC TANK

LENGTH: Twice the breadth.
DEPTH: 1.5 to 2 meters.
LIQUID DEPTH: 1.2 meters.
AIR SPACE: 30cms It is the level between
liquid and undersurface of cover.
BOTTOM: Sloping towards inlet end for
retentions of solids.
INLET AND OUTLET:
COVER: Concrete slab with a manhole.
RETENSION PERIOD: 24hrs if it is too small
inadequate treatment too long undue septicity occurs

• WORKING: That is purification of sewage by 2 stages
Anaerobic digestion in septic tank proper
Aerobic oxidation out side the septic tank in the sub soil
Sludge and scum  anaerobic digestion  effluent  aerobic oxidation
Septic tank-contd.

MAINTAINANCE: Disinfectants should be avoided as they are
injurious to bacterial flora of tank.
De sludging should be done as excessive accumulation interfere
with proper working
Newly built tanks first fill with water up to the outlet then with sludge
to provide right type of bacteria to carry out decomposition process.
Septic tank-contd.

5.Aqua Privy
• Similar to septic tank
• For a family per 6 years

III) Latrines suitable for temporary use/ camps
1. Shallow trench latrine
2. Deep trench latrine
3. Pit latrine
4. Borehole latrine

Trench Latrines
Dug up Earth
piled up on
the side for
covering

Trench Latrines
Shallow trench latrine Deep trench latrine
• 30 cm wide
• 90-150 cm deep
• Serves for a week
• 75-90cm wide
• 1.8 – 2.5cm deep
• Serves for weeks to months

Next class-Sewered areas and sewaget/t

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Environment - Solid Waste and Excreta Disposal

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