ORG RECYCLING COMPOSTING, Vermicomposting.pptx

Organic waste is any material
that is biodegradable and comes
from either a plant or an animal.
Biodegradable waste is
organic material that can be
broken into carbon dioxide,
methane or simple organic
molecules.
ORGANIC WASTE

Food waste Agricultural waste Sludge
Seafood processing
waste
Animal waste Brewery waste Textile mill waste

8-10% of CH4
emissions are
from organic
waste dumped in
landfills

Organic recycling is the process of
converting organic waste materials
into compost or other valuable
products that can be used to improve
soil health, reduce the amount of
waste sent to landfills, and mitigate
greenhouse gas emissions.
ORGANIC RECYCLING

Gas energy
Liquid energy
Organic acids
Biodegradable plastics
Protein products
Bioflocculants
Compost
VALUABLE PRODUCTS

• Composting and recycling organic waste
means that there is less waste being sent
to landfills, which can help to conserve
valuable landfill space and reduce the
environmental impacts associated with
waste disposal.
• Landfills are a major source of
methane emissions, which contribute
to climate change and can also create
safety hazards, such as the risk of
explosions or fires.
• By diverting organic waste from landfills
and converting it into compost or other
products, organic recycling can help to
reduce the amount of methane produced
by landfills and mitigate their
environmental impacts.
REDUCE THE AMOUNT OF WASTE SENT TO
LANDFILLS

Compost is a nutrient-rich soil
amendment that is made by combining
organic waste materials with other
ingredients, such as leaves, straw, or
sawdust, and allowing the mixture to
decompose over time.
Compost can be used to improve the
structure and water-holding capacity
of
the soil, increase nutrient
availability,
and support healthy plant growth. In
addition, composting can help to
reduce
the need for chemical fertilizers and
pesticides, which can have negative
impacts on soil health and the
environment.
CREATING VALUABLE COMPOST THAT CAN BE
USED TO IMPROVE SOIL HEALTH AND FERTILITY

Another benefit of organic recycling is
its ability to create jobs and support
local economies.
Organic recycling facilities require
skilled workers to operate and
maintain
the equipment used to process organic
waste materials.
In addition, the products produced by
organic recycling facilities, such as
compost and other soil amendments,
can
be sold to farmers, landscapers, and
other customers, providing a source of
income for local businesses and
supporting the development of a circular
economy.
SUPPORTING LOCAL WORKERS

Organic recycling can also help
to reduce the costs associated with waste
management.
Landfill disposal is often expensive, as it
requires significant infrastructure and
ongoing maintenance.
By diverting organic waste from
landfills and processing it through
composting or other organic
recycling
methods, municipalities and waste
management companies can reduce
their
costs and potentially generate
revenue
through the sale of compost or other
products.
REDUCING COSTS

In addition to these benefits, organic
recycling can also contribute to
broader sustainability goals, such as
reducing carbon emissions and
promoting resource efficiency.
By transitioning to a more circular
economy that values the reuse and
recycling of materials, we can
reduce our reliance on finite
resources and create a more
sustainable future for generations to
come.
ENVIRONMENT FRIENDLY APPROACH

Composting is a process by which
organic wastes are converted into
organic fertilizers by means of
biological activity under controlled
conditions.
COMPOSTING

COMPOSTING
• It is an important technique for recycling
organic
(agricultural and industrial) wastes
• Improve quality and quantity of organic fertilizers.
• Composting is a self heating, thermophilic and aerobic
biological process occurs naturally in heaps
of biodegradable wastes
• Different heterophyllic microorganisms, bacteria, fungi,
actinomyctes and protozoa, which derive their energy
and carbon requirements from the decomposition
of carbonaceous materials are involved in composting
• Narrowing down of C: N ratio to a satisfactory level
(10:1 to 12:1)
• Total destruction of harmful pathogens

• Livestock and human wastes
• Crop residues, tree litter and
weeds
• Green manure
• Urban and rural wastes
• Agro industrial by-
products
• Marine wastes
ORGANIC SUBSTRATES FOR COMPOSTING

ESSENTIAL REQUIREMENTS OF COMPOSTING
Bulky organic refuse:
stubbles, cotton stalks,
ground nut shell,
weeds, leaves, dust bin
refuse etc.
Starter material:
Cattle dung, urine, night
soil, sewage, urea,
rockphosphate or any
other readily available
nitrogenous substance and
microbial cultures.
Water: to keep the
moisture content of
the material at a
level of 50%.
Air: especially in
initial stages of
decomposition.

DIFFERENT METHODS OF AEROBIC COMPOSTING
Indore Composting
NADEP method
of composting
Vermicomposting

NADEP METHOD
• NADEP method of making compost was invented by a farmer
Narayan Deotao Pandharipande(also popularly known as “Nadep
kaka”)living in Maharashtra.
• This method become quite popular among the farmers in
Western India.
• NADEP method uses a permanently built tank of mud or clay,
bricks or cement.
(Composting structure : All the four walls of
NADEP tank are provided with vents by
removing every alternate brick after the height
of 1ft. from bottom for aeration. Walls built like
honeycombs through which water is sprayed)

STEPS FOR NADEP METHOD OF COMPOSTING.
1.Selection of site-
The tank should be located near the cattle shed or farm site.
2. Size of pit-
The tank should be 12ft (length) X 5ft (breadth) X 3ft (height) keeping proper
spacing for aeration.(proper holes of 6 or 7 inches are left on all the four sides of
the tank wall)
3.Materials required
• a)Brick(1000nos).
• b)Organic waste/biomass(2000kg).
• c)Cow dung/biogas slurry(200-500kg).
• d) Soil of fertile land(700-800kg).
• e)Cow urine(40-50lt).
• f)Water(as per needed).

4.METHOD OF PREPARATION
• Make rectangular brick structure of specific size
(12’X5’X3’) keeping proper spacing for aeration(some
bricks should be removed from each sides for aeration).
• Plaster walls on all sides with mud and cow dung.
• 1st layer should be of dry biomass (upto 6”)containing
weeds and other crop residues.
• Make slurry of 10-15kg cow dung with water and 5 litre
cow urine.
• As 2nd layer apply the cow dung slurry. 3rd layer spread
fertile soil above it and moisten with water. Repeat the
process till the heap attains a height of 4-5 feet. Plaster
the heap on the top with soil and cowdung slightly in
dome shaped manner.
• Within 7-15 days,all the materials in the pit get
decomposed and the heap attains a height upto 1-1.5 feet
below the top of the surface.

• Then again fill the pit by same process and raise
height of the heap to the original and plaster from
the top with cowdung and soil. Inorder to maintain
15 to 20% moisture, the compost is sprinkled with
cow dung and water. This helps in conservation of
nutrients
• After this, the tank is not disturbed for 3 months
except that is moistened at intervals of every 6-15
days.
• The entire tank is covered with a thatched
roof to prevent excessive evaporation of
moisture.
• Under no circumstances should any cracks
be allowed to develop. If they do should be
promptly filled up with slurry.
• Compost get prepared within 100-120 days.

This method was developed by
A. Howard and Y. D. Wad
Materials required:
Plant residue
Dung
Urine soaked
earth
Wood ash (source of
potassium) Water
Composting structure:
Pit of 2m width, 1m depth and 5m
or above length as per requirement
INDORE METHOD

INDORE METHOD
Advantages
• Capital expenditure low
• Process is fast
• Eco friendly method
Disadvantages
• Requires labour for turning,
• Not practical if large quantity of
material is there
• Site should be at elevated level,
near a cattle shed and water
source.

ADVANTAGES
•
•
•
•
•
•
•

Earthworms can be multiplied
in 1:1 mixture of cowdung and
decaying leaves
50 numbers per 10 kg of
organic wastes
Within 1-2 months it
multiplies by 300 times
MASS MULTIPLICATION OF EARTHWORMS

ADVANTAGES AND DISADVANTAGES OF
AEROBIC COMPOSTING
•Disadvantages
• Higher capital cost for aeration
equipments.
• Higher operating
cost(particularly energy for
pumps or aerators).
• Higher maintenance
requirements.
Advantages
• Large reduction of valuable
waste.
• Improves soil’s ability to
sequester carbon.
• Reduce pesticide usage and
synthetic fertilizer dependencies.

VERMICOMPOSTING OF HOUSEHOLD
WASTES

A WOODEN BOX OF 45 CM X 30 CM X 45 CM OR AN
EARTHEN/PLASTIC CONTAINER WITH BROAD
BASE AND DRAINAGE HOLES MAY BE SELECTED.

A PLASTIC SHEET WITH SMALL HOLES
MAY BE PLACED AT THE BOTTOM OF THE
BOX / CONTAINER

A LAYER OF SOIL OF 3 CM DEPTH AND A
LAYER OF COCONUT FIBRE OF 5 CM DEPTH MAY
BE ADDED ABOVE IT FOR DRAINING OF EXCESS
MOISTURE.

A THIN LAYER OF COMPOST AND WORMS MAY BE
ADDED ABOVE IT. ABOUT 250 WORMS ARE
SUFFICIENT FOR THE BOX.

VEGETABLE WASTES OF EACH DAY CAN BE SPREAD IN
LAYER OVER THE COCONUT HUSK FIBRE

TOP OF THE BOX MAY BE COVERED WITH A PIECE OF
SAC TO PROVIDE DIM LIGHT INSIDE THE BOX.

WHEN THE BOX IS FULL, IT CAN BE KEPT
WITHOUT DISTURBANCE FOR A WEEK.

WHEN THE COMPOST IS READY, THE BOX CAN BE KEPT
OUTSIDE FOR 2-3 HOURS SO THAT THE WORMS COME
DOWN TO THE LOWER FIBRE LAYER. COMPOST FROM
THE TOP, MAY BE REMOVED, DRIED AND SIEVED.

THE VERMICOMPOST PRODUCED HAS AN
AVERAGE NUTRIENT STATUS OF 1.8 PER CENT N,
1.9 PER CENT P2O5 AND 1.6 PER CENT K2O, BUT
COMPOSITION WILL VARY WITH THE SUBSTRATE
USED.

• It is an extract of
compost containing
worms.
• Vermiwash is honey-
brown in colour
• pH - 8.5
• N, P2O5 and K2O content
200, 70 and 1000 ppm
• Nutient content is greater
VERMIWASH

• The vermi wash, either alone or in
combination with botanical
pesticides can be used for pest
management in kitchen gardens
• When vermicompost is applied as
organic manure instead of FYM, the
quantity of in-organic fertilizers can
be reduced to about half the
recommended dose.
RECOMMENDATION FOR CROPS

The system consists of a plastic
basin having a capacity of 20
litres, a plastic perforated
wastepaper basket and a PVC
pipe of 5 cm diameter and 30
cm length.
METHOD 1

• The waste paper basket is covered with a nylon net
and placed at the centre of the basin upside
down. A hole is made at the bottom of the
waste paper basket so that a PVC pipe of 5 cm
diameter can be placed into the basin
through the hole in such a way that one end of
it touches the basin.

• The PVC pipe is perforated so that the leachate
from the basin seeps through the wastepaper
basket and collects in the PVC pipe, which
can be siphoned out by a kerosene pump.

The basin outside the
wastepaper basket, is lined
with a layer of brick pieces
at the bottom and a 2-3 cm
thick layer of coconut fibre
of 2-3 cm placed above it.

AFTER MOISTENING THIS, 2 KG
WORMS (ABOUT 2000) ARE
INTRODUCED INTO IT AND 4 KG
KITCHEN WASTE IS SPREAD
OVER IT

AFTER ONE WEEK,
THE KITCHEN
WASTE TURNS INTO
A BLACK WELL
DECOMPOSED
COMPOST.

After one week, the kitchen
waste turns into a black
well decomposed compost.
Two litres of water is
sprinkled over the compost
containing worms.

AFTER 24 HOURS,
THE LEACHATE
COLLECTED IN
THE PVC PIPE IS
REMOVED BY
SIPHONING

FOR LARGE SCALE
COLLECTION OF
VERMIWASH, A
CEMENT TANK OF
SIZE 80 CM X 80 CM
X 80 CM WITH A
SIDE TAP IS
CONSTRUCTED.

A LAYER OF SMALL
BRICK PIECES OR
GRAVEL IS PLACED
AT THE BOTTOM OF
THE TANK.
ABOVE IT A LAYER
OF FIBRE OF 3-4 CM
THICKNESS IN
PLACED.

A definite quantity of
biowaste (4 kg) is added to
the system along with 2 kg
of earthworms. After two
weeks, the entire mass of
biowaste will turn to
brownish black compost.

It is sprinkled with 2 litres
of water. Vermiwash is
collected through the side
tap after 24 hours.
Biowaste can again be
added to the system and the
process repeated.

METHOD 2
• This is a simple and economical
technique to collect vermiwash.
The system consists of an earthen pot
of 10 kg capacity with a hole at the
bottom, which is filled with pieces of
stone up to a height of 10 cm from the
bottom.

• A plastic net is spread over this. Then a
thick layer of coir fibre along with
humus containing 1500- 2000
worms of Eudrillus euginae or Isenia
foetidae is added to the pot

• The hole situated at the bottom of the pot is
fixed with a water tap through which
vermiwash is collected.
• The kitchen waste of each day is added to
the container.
• The composting process is allowed to
continue for a week or more till brownish
black mass of compost is obtained.
• Occasionally, two or three tablespoons
of fresh cowdung slurry is poured on the
humus as feed for the worms.
• After the formation of compost, the
entire mass is soaked with two litres of
water.
• After 24 hours, about 1.5 litre of
vermiwash can be collected.

• This process can be continued for
one or two weeks till the brown
colour of wash disappears.
• The less enriched compost that
remains in the pot can be collected
and used as fertilizer.
• Later, the pot can be emptied and
set up again to continue the
process.

BENEFITS OF VERMICOMPOST
• When added to clay soil, loosens the soil and provides the passage for the
entry of air.
• The mucus associated with it being hygroscopic, absorbs water and
prevents water logging and improves water holding capacity.
• In the vermicompost, some of the secretions of worms and the
associated microbes act as growth promoter along with other
nutrients.
• It improves physical, chemical and biological properties of soil in the
long run on repeated application
• The organic carbon in vermicompost releases the nutrients slowly and
steadily into the system and enables the plant to absorb these nutrients.
• The multifarious effects of vermicompost influence the growth and yield
of crops.
• Earthworm can minimize the pollution hazards caused by organic waste
by enhancing waste degradation.

• Coirpith, is produced in large
quantities as waste material of the
coir industry. Every year,
approximately 2.5 lakh tonnes of
coirpith accumulate in Kerala as
waste.

COIRPITH HAS
WIDE C:N RATIO
AND ITS LIGNIN
RICH NATURE
DOES NOT
PERMIT NATURAL
COMPOSTING
PROCESS AS IN
OTHER
AGRICULTURAL
WASTES

Mushrooms belonging to the
genus Pleurotus have the
capacity to degrade part of the
cellulose and lignin present in
coirpith by production of
enzymes such as, cellulases and
lactases, bringing down the
C:N ratio as well as lignin
content

MATERIALS REQUIRED:
• Coirpith 1 tonne
• Urea 5 kg
• Mushroom
(Pleurotus) spawn 1.5
kg.

A SHADED PLACE OF 5 M X
3 M DIMENSION MAY BE
SELECTED AND LEVELLED
AFTER REMOVING WEEDS.

100 KG COIRPITH
MAY BE SPREAD
UNIFORMLY.

SPREAD 300 G (ONE
BOTTLE OR COVER) OF
PLEUROTUS SPAWN ON
THIS AND COVER WITH
A SECOND LAYER OF
100 KG COIRPITH.

ON THE SURFACE OF
THE SECOND LAYER,
SPREAD 1 KG UREA
UNIFORMLY.

Repeat this sandwiching
process of one layer of coirpith
with spawn followed by
another layer of coirpith with
urea up to 1 m height.

SPRINKLE WATER IF
NECESSARY TO KEEP
THE HEAP MOIST.
ALLOW THE HEAP TO
DECOMPOSE FOR ONE
MONTH

The coirpith is converted into
good manure after 30- 40
days and the lignin content is
reduced from 30 per cent to
40 per cent.
Another significant change is
the lowering down of C: N
ratio from 112:1 to 24:1.

• This coirpith compost
contains macro nutrients as
well as micronutrients. It
has the unique property
of absorbing and
retaining moisture to
about 500-600 per
cent. It improves the
water infiltration rate and
hydraulic conductivity of
soil.

• In this decomposition occurs in the absence of oxygen
or under the limited supply of oxygen, Anaerobic
microorganisms dominate.
• They produce the intermediate compounds like
methane, organic acids, hydrogen sulphide and
other substances.
• It is a low temperature process.

ANAEROBIC MICROBIOLOGY
• The anaerobic microbiology mainly involves three
group of microorganisms.
• They are
• Methanobacterium
• Methanococcus
• Methanospirillum

BANGLORE METHOD
• This method of composting was
developed at Bangalore by Acharya in
1939.
• This method is suitable in areas
with scanty rainfall.
• Time involved in production of
finished compost is much longer.
• The composting is done in trenches
and the material is not turned.

• Trenches or pits of 1m depth, convenient length and breadth are
dug.
• Organic residues and dung and urine soaked mud are put in
alternate layers.
• These layers are repeated in order at least 1.5-2m above ground
level.
• It is left exposed without covering for 15days.
• Then it is plastered with earth or mud of 1cm thick,
• It takes about 6-8 months to get finished product.
• It is the bulkiest compost.

BANGLORE METHOD
MERITS
• Turning not required
• Simple and easy to manipulate.
• Efficient use of moisture
• High manure recovery
• Pathogen and weed free manure
DEMERITS
• Long duration
• Low nutrient recovery

ENRICHMENT OF COMPOST WITH MICROBIAL
INOCULANTS.
• Compost prepared by traditional method is usually low in nutrients
and there is need to improved its quality.
• Enrichment of compost using low cost nitrogen fixing and phosphate
solubilizing microbes is one of the possible way of improving
nutrient status of the soil.
• It could be achieved by introducing microbial inoculants, which
are more efficient than the native strains associated with substrate
materials.
• Both the nitrogen fixing and phosphate solubilizing microbes are
more exacting in their physiological and ecological requirements.
The only alternative is to enhance their inoculum potential in the
composting mass.

AEROBIC COMPOSTING USING
MICROBIAL CONSORTIUM

MICROBIAL
CONSORTIUM
Liquid
formulation
Thumuburmuzhi
Composting
Coirpith based
formulation
Kau smart biobin
Bacillus subtilis
BaBc-1
Trichoderma
asperellum
(KAU
isolate)
Bacillus sp.
BaOu-1

• Recommended for large
scale composting
• Done in ferro-cement
tanks
THUMUBURMUZHI COMPOSTING

• The panels placed with a gap
of 4 cm
• The tanks are placed in a
well ventilated space with
protection from rain

DEPOSIT DRY LEAVES AT A
THICKNESS OF 6 INCHES AT
THE BOTTOM OF THE TANK

DILUTE THE COMPOSTING
TONIC BY ADDING 4 TIMES
THE VOLUME OF WATER

50 ML COMPOSTING
TONIC IN 200 ML WATER

ABOVE THIS 6 INCH THICKNESS
OF BIO SOLID WASTE CAN BE
PLACED WHICH CAN INCLUDE
FOOD WASTE, MARKET WASTE
ETC

• Waste should be placed in the
middle of the tank inorder to
prevent spilling and exposure
• It can also prevent the entry of
flies into the compost
• Liquid waste should not used
and the optimum moisture for
composting is 40-50 percent

ABOVE THIS ANOTHER 6
INCH THICK LAYER OF DRY
LEAVES ARE PLACED

APPLY ANOTHER 250 ML
OF COMPOSTING INOCULUM

• The process is repeated until the
tank is filled
• The waste is converted into
compost after 90 days

THE DECOMPOSED PRODUCT
IS TAKEN OUT SIEVED AND
CAN BE DIRECTLY USED AS
COMPOST

THE QUALITY OF THE
COMPOST OBTAINED
SHOULD BE TESTED FOR
NUTRIENT STATUS, HEAVY
METALS AND PATHOGENS

It is composting unit for aerobic
composting of food waste,
kitchen waste and fruits and
vegetables waste produced by
households on daily basis
KAU SMART BIOBIN

THE BIOBIN CONSIST OF
TWO CONSECUTIVE RINGS
AND A BOTTOM TRAY FOR
COLLECTION OF COMPOST

THE OUTER RING IS MADE OF
STAINLESS STEEL (COIN MESH)
AND THE INNER RING IS MADE
OF GI MESH

THE SPACE BETWEEN THE
INNER AND OUTER RING IS
FILLED WITH DRY LEAVES

Uses of dry leaves
• Prevents rodents and other
insects from entering inner
chamber which contains the
biowaste
• Provides aeration
• Absorbs excess water released
during decomposition

AT THE BOTTOM OF INNER
BIN A CIRCULAR PIECE OF
NEWSPAPER OR 0.5 INCH OF
CRUSHES DRY LEAVES IS
PLACED TO PREVENT THE
WASTE FROM FALLING
DIRECTLY INTO THE
COLLECTION TRAY

ABOVE THE NEWSPAPER A
LAYER OF BIODEGRADABLE
SOLID WASTE IS SPREAD
EVENLY

APPLY A LAYER OF 3 TO 4
HANDFULS OF COIRPITH
BASED INOCULUM ABOVE
THE WASTE

THE PROCESS OF
COMPOSTING BEGINS IN
ABOUT 45 DAYS

WASTE CAN BE COLLECTED
IN THE TRAY WITH IS
PLACED AT THE BOTTOM

Developed in College of
Agriculture, Vellayani
Composting inoculum

Close the drainage hole of the pot
Fill the bottom layer with coirpith

FOR 1 KG OF WASTE
APPLY 10G OF THE
INOCULUM

When the pot is filled cover it
with a heavy tile or any other
material
The compost will be ready in
40-45 days

The process of converting organic waste materials into compost or other
valuable products that can be used to improve soil health, reduce the amount
of waste sent to landfills, and mitigate greenhouse gas emissions
a) recycling b) Organic recycling
c) Susutainable waste management d) None of these

The gas formed during anaerobic decomposition of organic matter
Methane Carbon dioxide
Nitrous oxide CFC

Which of the following are aerobic methods of composting
NADEP method Vermicomposting
Indore method All of these

The most common earthworm species used for composting
in kerala
a) Eudrillus euginea b) Perionix excavatus
c) Both d) None

1. The coconut husk in vermicomposting is laid concave side up
2. It is to ensure the drainage
1 and 2 are correct Only 1 is correct
Only 2 is correct 1 and 2 are wrong

1. Eudrillus euginea are called African night crawlers
2. They are surface dwellers

The moisture of vermicompost is maintained at
40-50% 50-60%
Both are correct None of these

Time taken for vermicomposting
60-75 days 50-60 days
40-55 days 45-50 days

1. Vermiwash is honey brown in colour
2. The pH of vermiwash is acidic

1. Vermiwash is honey brown in colour
2. The pH of vermiwash is acidic( 8.5-
so basic)

1. Earthworms can be multiplied in 1:1 mixture of cowdung
and decaying leaves
2. Within 1 -2 months it multiplies by 200 times

1. Earthworms can be multiplied in 1:1 mixture of cowdung
and decaying leaves
2. Within 1 -2 months it multiplies by 200 times 300 times

Which of the following is not an organic waste
Sludge Agricultural waste
Food waste None of these

The NPK content of vermiwash
a) 200:70:1000 ppm b) 20:70: 100 ppm
c) 200:70: 100 ppm d) 200:700:1000 ppm

Coirpith has wide C:N ratio as it is rich in
a) Cellulose b) Lignin
c) Sclerotin d) Chytin

The change in C:N ratio after coirpith composting
a) 112:1 to 24:1 b) 100:1 to 25:1
c) 113:1 to 20:1 d) None of these

Which of the following is anaerobic method of composting
a) Indore method b) Coirpith composting
c) Banglore method d) None of these

Which of the following mushroom species is used for
coirpith composting
a) Pleurotus b) Agaricus
c) Volvariella d) Oyster

The fertilizer involved in coirpith composting
a) Urea b) MOP
c) Rock phosphate d) None of these

What are the advantages of vermicompost
a) When added to clay soil, loosens the soil and provides the
passage for the entry of air.
b) The mucus associated with it being hygroscopic, absorbs water
and prevents water logging and improves water holding capacity.
c) In the vermicompost, some of the secretions of worms and the
associated microbes act as growth promoter along with other
nutrients.
d) All of these

Time taken for coirpith composting
a) 1 month b) 2 months
c) 3 months d) None of these

pH of vermiwash
a) 8.5 b) 9.5
c) 10 d) None of these

a) 8.5 b) 9.5
c) 10 d) None of these
pH of vermiwash

1. Vermiwash is alkaline in pH
2. It has insecticidal properties
a) 1 and 2 correct b) 1 is wrong
c) 1 and 2 are wrong d) 2 is correct

ORG RECYCLING COMPOSTING, Vermicomposting.pptx

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