solid waste and waste management

SOLID WASTE

Some terms we need to know

REFUSE:Solid or semisolid waste matter produced in the normal course of

human activities. Generated from street sweepings, markets, stable

litter, industrial refuse, commercial refuse, etc.

RUBBISH:Solid wastes originating in houses, commercial establishments,

industries, excluding garbage and ash.

GARBAGE:Animal & vegetable wastes resulting from the handling, storage,

sale, preparation, cooking and serving of food.

ASH:Residue from burning of wood, coal, charcoal and other combustible

materials used for cooking and heating purposes in houses, industries

etc.

• Street refuse

• Market refuse

• Stable litter

• Industrial refuse

• Domestic refuse

Sources of solid wastes

In most of the countries the per

capita daily solid waste produced is

between 0.25 to 2.5 Kg

• Galvanized steel dust bin with cover (for households) – 0.05 to 0.1 cubic feet per capita per day.

– A bin with capacity of 1.5 cubic feet for a family of 5 members if collection is done every 3 days.

• Public bins.

Storage of solid wastes

• House-to-house collection

• Mechanical transport

• Dustless refuse collector

Collection of solid wastes

Methods of solid waste disposal

INSANITARY METHODS

1. Hog feeding

2. Dumping

SANITARY METHODS

1. Sanitary landfill/ Controlled tipping

2. Composting

3. Incineration

4. Manure pits

5. Burial

6. Biogas plant

SANITARY METHODS

Methods of solid waste disposal

INSANITARY METHODS

Dumping

– Refuse dumped in low lying areas

– Bacterial action over time, decreases volume of refuse which is gradually converted into humus

– Disadvantages

• Smell

• Unsightly appearance

• Free access to flies, rodents, hogs, dogs etc.

• Dispersal by wind

• Pollution of surface and ground water

Dumping

1. Sanitary landfill / Controlled tipping

–Laying of dry and condensed refuse in a trench or other prepared area with intervening earth coverings.

–Anaerobic digestion of the refuse takes place. The process takes 4-6 months to complete.

SANITARY METHODS

2-3

mete

r

4-12 meter

• Trench method

– Level ground

– Trenches 4-12 m wide, 2-3 m deep

– Refuse is compacted and then covered with excavated earth

• Ramp method

– Sloping terrain

• Area method

– Land depressions, disused quarries, pits

– May need soil from outside sources to cover the compacted refuse

2. Composting–Method of combined disposal of refuse and nightsoil or sludge.–Organic matter breaks down under bacterial action, producing “compost” –used as manure.

SANITARY METHODS

BANGALORE METHOD

MECHANICAL

COMPOSTING

VERMI-COMPOSTIN

G

Three methods of composting

Bangalore method

Anaerobic composting; also called “Hot fermentation process”IISc, Bangalore – Indian Council of Agriculture Research

800 metre

90

cm

4.5 – 10 m

A Trench excavated for

composting

Anaerobic

decomposition

4-6 monthsHumus

NIGHTSOIL

15

cm

5

cm

15

cm

5

cm

25

cm

REFUS

E

REFUS

E

NIGHTSOIL

REFUS

E

Earth

NIGHTSOIL

Mechanical composting

Refus

ePulverizing

equipmentPulverized refuse +

Sewage/Sludge/NightsoilIncubation

(Temperature, pH, Aeration, Moisture controlled)

Complete

composting

Screening

4-6 weeks

Vermicomposting

A method of garbage disposal

Garbage Earthworms

2-3 months

Compost

3. Incineration–Suitable for areas where land is not available for sanitary landfill–Example: Hospitals–Disadvantages:

•Expensive•No useful by-product•Air pollution

SANITARY METHODS

4. Manure pits–Used in rural households–Covered with earth after each days dumping–Two pits–Within 5-6 months decomposed refuse which is used as fertilizer

SANITARY METHODS

5. Burial–Suitable for small settlements/camps–Decomposed matter may be ready for use as manure within 4-6 months

SANITARY METHODS

1.5 m

2 m

20-30

cm

40 cm1 m

200 persons

1 week

6. Biogas plant• Biogas is produced by the

anaerobic breakdown of solid waste /excreta.

• Biogas (Methane, CO2, Hydrogen) can be used as a fuel for any heating purpose, such as cooking.

SANITARY METHODS

EXCRETA

Spread of disease from excreta

Sanitation barrier

Methods of excreta disposal

INSANITARY METHODS

1. Bucket type

2. Conservancy system/Cartage

SANITARY METHODS

WATER CARRIAGE SYSTEM

1. Bore hole latrine

SANITARY METHODS

Methods of excreta disposal

2.Dug well/pit latrine

3. Water seal type

of latrinea) P.R.A.I

b) R.C.A

c) Sulabh

sauchalya

4. Septic tank

5. Aqua privy

13-03-2015 Free template from www.brainybetty.com

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3.latrine suitable for

camps

i. Shallow trench

latrines

ii. Deep trench latrine

iii.Pit latrine

iv.Bore hole latrine

Water carriage system and sewage treatment

A) PRIMARY TREATMENT

• screening

• Removal of grit

• Plain sedimentation

B ) SECONDARY TREATMENT

• Trickling filters

• Activated sludge process

c) OTHER METHODS

a) Sea outfall b) river outfall

c) Sewage farming d) oxidation ponds 33

INSANITARY METHODS OF EXCRETA DISPOSAL

1. Open defecation

2. Cartage (Conservancy

system)•Example: Bucket latrine

•Disadvantages:

Smell

Flies

Health risk to people handling

the excreta

Health risk from food crops

fertilized with raw excretaBucket

latrine

SANITARY METHODS OF EXCRETA DISPOSAL

9b. Bore Hole Latrine

• Introduced in India by Rockefeller Foundation in

1930’s as a component of hookworm control

programme.

• Consists of a circular hole dug by an equipment

called “auger”.

20 f

eet

16 feet

1a. Simple pit latrine

Lo

ca

tio

n o

f a

pit

la

trin

e

Ad

va

nta

ge

s &

D

isa

dva

nta

ge

s• Advantages:

– Easy and cheap to construct

– Slab and shelter can be reused

– Excreta are isolated

• Disadvantages:

– Unpleasant odors

– Flies

• A circular pit about 75cm in diameter and 3-3.5m deep is dug into ground for reception of nightsoil.

• The pit lined with pottery rings to prevent of soil reenter.

• Concrete squatting plate is placed on top.

• Merits: 1. easy to construct

• 2. longer life

1b. Dug well latrine

0.5 m

Semi

dark

Shelter

Water Seal Latrine:• Hand flushed water seal latrine.

• Water seal

• Types of water seal:

44

Wa

ter

se

al

latr

ine

The Water Seal

2a. Direct & Indirect WS Latrine

Direct Indirect

2c. PRAI & RCA Latrine

• PRAI Latrine was developed by the Planning, Research & Action Institute, Lucknow

• RCA latrine was developed by the Research Cum Action project of the Ministry of Health

The RCA Latrine

1. Location

2. Squatting plate

3. Pan

4. Trap

5. Connecting pipe

6. The pit

7. Superstructure

8. Maintenance

9. Modifications

Location

•Depends on porosity of soil and ground water level

•Usually, at least 15 m away from water source

Squatting plate

•Made of impervious material (cement concrete)

•3’x3’x2”

•Raised footsteps

Pan

•Receives nightsoil, urine and water

Trap

•A bent pipe connected to the pan

•Holds water and serves as a water seal (2 cm depth)

Connecting pipe

•Needed when pit is sited away from squatting plate

•Not needed in Direct type RCA Latrine

•3.5” diameter with a bend at the end

The pit

•Covered, rectangular/circular

•75 cm diameter, 3-3.5 m deep

• Underneath squatting plate(Direct) or offset (Indirect)

Superstructure

Maintenance

•Regular cleaning of the squatting plate

•Flushing with 1-2 lts of water after every use

Modifications

•Using prefabricated squatting plate/pan made of china

clay

•Using a septic tank instead of the pit

Squatting plate13-03-2015 Free template from

www.brainybetty.com53

Pan and connecting pipe

54

• The aquaprivy is a water tight tank filled with water into which excreta fall via a drop pipe, connected to a seepage pit (soakaway) to dispose of sullage and effluent.

• Drop pipe must reach below surface of the water.

• Night soil undergoes purification by anerobicdigestion

Vent open on top

Sludge removed at end.

4. Aqua privy

The AQUAPRIVY

Ad

va

nta

ge

s &

D

isa

dva

nta

ge

s• Advantages:

– Cannot be blocked with bulky anal cleaning material

– Nil problem with odor or flies

– Can be connected to a sewerage system at a later date

• Disadvantages:

– Expensive to build

– Need large volumes of water to work

– Water seal may be hard to maintain

– Tanks must be emptied about every 3 years

• Septic tanks are watertight chambers (single, double or multi chambered) which receive excreta and wastewater.

• They are connected to a soakaway which receives liquid overflowing from the tank.

5. Septic Tank

Wo

rkin

g o

f S

ep

tic T

an

k• Solids (“sludge”) settle down and are

purified by anaerobic digestion.

• The liquids (“effluent”) undergoes

aerobic oxidation in the upper layers of

the soil, outside the septic tank proper.

• The sludge is reduced in volume and a portion of solids is transferred to liquids and gases which rises to surface forming bubble.

• Liquid passes out called effluent which percolates into soil by open ended pipes laid in trenches.

• Aerobic bacteria attack organic matter and convert to end products .

•

• Complete purification of sewage.

62

Ad

va

nta

ge

s &

D

isa

dva

nta

ge

s• Advantages:

– Isolation and treatment of excreta

– No odor or fly problems

– May be connected to sewerage system at a later date

• Disadvantages:

– High cost of construction

– Need for periodic mechanical emptying

– Need for large volumes of flushing water

– Only suitable where flush toilets are used


64

• A low cost, water seal type of latrine connected to a 3’x3’x3’ pit. It is a modified handflush latrine with a specially designed pan and trap – needs very little water for flushing.

• Sulabh International, an NGO, maintains SulabhCommunity Latrines – ‘pay-and-use system – in many parts of India.

6. Sulabh Shauchalaya

SHALLOW TRENCH LATRINE

• Simple trench dug with ordinary tools.

• Trench is 30cm wide 90-150cm deep.

• Separate for men and women

• Earth piled up a side and people instructed to cover up earth after each defecation.


66

Shallow Trench latrine

Access

pathHandwashing

facilityDug soil (for back filling)

Trench depth

approx. 150

mm

Poles to attach

screeningSecurity screening

Superstructure

Plan View

1.5

m

5 m 4 m

Approx

.

300mm

DEEP TRENCH LATRINE:

• Used for camps in longer duration

• Trench is 1.8-2.5m

• 75-90cm wide

• Squatting plate is provided.


69

De

ep

Tre

nch

la

trin

e

Superstructure

Modern sewage treatment.

• A) primary treatment

• B) secondary treatment

•

• PRIMARY TREATMENT

• 1.Screening

• 2. Grit Chamber

• 3. Primary Sedimentation.


72


73

• Sewage made flow across tank , spends 6-8hrs in

tank

• Purification takes place mainly by sedimentation

• 50-70% settle down under influence of gravity.

Coli form organism formed called ‘sludge’

Biological action takes place were micro-organism

attack sewage

Sewage attack complex organic solids and break them 74

• Simpler soluble substance ammonia

• Contain grease and fat that come up called scum

• Then it is treated with lime ,aluminium sulpahte and ferrous sulphate.


75

Secondary treatment:

• Types

76

ACTIVATED SLUDGE

PROCESS

Oxygen pond


77


78

solid waste and waste management

Education

commercial refuse

compacted refuse

daily solid waste

condensed refuse

volume of refuse

storage of solid wastes

semisolid waste matter

sanitary landfillexample