Definition of Waste:

Waste (or wastes) are unwanted or unusable materials. Waste is any

substance discarded after primary use, or is worthless, defective and
of no use. A by-product, by contrast is a joint product of relatively
minor economic value.
Types: There are several criteria for classifying waste depending on
i) Origin
ii) Biodegradability (its capacity to decompose naturally in the
environment )
iii)Composition (the material it is made of),
iv) Hazardousness or its physical state (solid, liquid, or gaseous)
Type of waste according to its origin ( 7 classes)
1)Domestic waste: That generated in homes as a result of daily activities:
food waste, packaging, paper, cardboard, plastics, or organic waste, such
as used cooking oil. The latter can be recycled and converted into
renewable fuels if it is transferred to any collection point.
2)Commercial waste:That coming from commercial activities, from offices
and services: paper, cardboard, packaging, food waste, cleaning waste...
3) Industrial waste: Produced as a result of industrial processes, such as
production waste, chemical waste, metals, plastics, and industrial
subproducts.
4)Health waste: That generated in hospitals, clinics, and health centers:
disposable medical materials, biological waste, expired drugs, infectious
waste, etc.
5)Mining waste: Derivatives from mineral extraction and processing
activities, such as rocks, soils, sludges, and mineral processing waste.
 • 6)Agricultural and livestock waste: Coming from these activities; crop
residues, manure, animal feed waste, or agricultural plastics, among
others.
• )Construction and demolition waste such as rubble, wood, metals,
bricks, and concrete.

Types of waste according to its biodegradability

A)Biodegradable : That can decompose naturally by the action of
microorganisms such as bacteria and fungi e.g.food waste, paper,
cardboard, wood, garden waste and agricultural waste;
B)Non-biodegradable: That which does not decompose naturally or does so
at an extremely slow rate.e.g.plastics, metals, glass, or batteries.
(When decomposed, biodegradable waste can be transformed into compost,
which serves as organic fertilizer, or into renewable fuels).
According to composition:
1.Paper and cardboard: They represent a significant part of the waste we
generate and are easily recyclable.
2.Glass: It is also highly recyclable. Moreover, recycled glass can be used
to manufacture a wide range of products, from packaging to construction
materials.
3.Plastics: They are further subdivided into different types according to
their chemical composition. i) recyclable,ii) nonrecyclable
4) Organic waste:Easily recyclable if it is separated correctly at source
5) Hazardous Waste:It requires a special treatment to minimize its impact
on the environment
6)Electronic waste:Like the former, it needs a proper treatment to ensure
reuse and recycling of its components.
Hazardous or its physical state
Solid waste : It refers to any discarded or unwanted solid materials. It includes
various items such as paper, plastics, glass and food waste. Solid waste can
include sludge from industrial plants or other discarded materials that result
from industrial, commercial, mining and agricultural operations.
Liquid waste: Liquid waste essentially is any waste that can be found in liquid
form, and is sometimes referred to simply as wastewater. It can be domestic,
commercial or industrial waste.
Gaseous waste : Gaseous waste refers to waste materials in the form of gases
that are produced as byproducts of industrial processes, such as carbon
dioxide, carbon monoxide, methane, and nitrogen oxides. These gases can
have various negative impacts on the environment, including global
warming, acid rain, and air pollution.
How to manage MSW:
• Source reduction, or waste prevention, is designing products to reduce
the amount of waste that will later need to be thrown away and also to
make the resulting waste less toxic.
• Recycling is the recovery of useful materials, such as paper, glass,
plastic, and metals, from the trash to use to make new products, reducing
the amount of virgin raw materials needed.
• Composting involves collecting organic waste, such as food scraps and
yard trimmings, and storing it under conditions designed to help it break
down naturally. •This resulting compost can then be used as a natural
fertilize .•Landfills are engineered areas where waste is placed into the
land. Landfills usually have liner systems and other safeguards to prevent
polluting the groundwater.
•Transfer Stations are facilities where municipal solid waste is
unloaded from collection vehicles and briefly held while it is
reloaded onto larger, long-distance transport vehicles for shipment
to landfills or other treatment or disposal facilities.
• Energy Recovery from Waste is the conversion of non-recyclable
waste materials into useable heat, electricity, or fuel.
Composition of municipal solid waste :
The municipal solid waste consists of organic waste, waste paper, plastic waste, tin
cans, aluminum cans, textile, glass, etc. as discussed in Chapter . It is always
recommended to establish a transfer station in rural communities because of low quantity.
Importance Of Waste Management
1) Environmental Protection: Proper waste management helps prevent
pollution of air, water, and soil. It reduces the release of harmful substances
into the environment, minimizing negative impacts on ecosystems,
wildlife, and human health.
2)Resource Conservation:It involves recycling and reusing materials,
reducing the need for new raw materials. This conserves natural resources
and energy, leading to more sustainable production processes.
3)Energy Savings:Many waste management practices, such as recycling
and waste-to-energy technologies, generate renewable energy or recover
energy from waste. This reduces the reliance on fossil fuels and helps
combat climate change.
4) Reduction of Greenhouse Gas Emissions:Proper waste management,
including recycling and composting, reduces methane emissions from
landfills and the need for energy-intensive production of new materials,
thereby mitigating climate change.
5) Health and Safety: It can lead to disease transmission, water
contamination, and air pollution. It minimizes health risks for communities
and workers in the waste industry.
6)Aesthetic Improvement: Proper waste disposal and cleanliness
contribute to visually appealing surroundings, enhancing the quality of life
for residents and attracting tourism.
7)Economic Benefits:It creates job opportunities in recycling, waste
collection, processing, and related industries. It also reduces the costs of
waste cleanup, disposal, and environmental remediation.
Compost can be enriched by adding various materials and
microbes,
A)Phosphate :Superphosphate, bonemeal, or phosphate rock can be added
to each layer of animal dung. Rock phosphate is a cheap source of
phosphorus that can improve the water and citrate soluble phosphorus in
compost. B)Animal bones : Boiling animal bones with wood ash leachate or
lime water and adding the residue to the compost can improve its nutrient
value. C)Wood ash :Wood ash waste can increase the potassium content of
compost. D)N-fixing and P-solubilizing cultures :These organisms can be
sprinkled into the compost after one month when the temperature has
stabilized. Examples include Azotobacter, Azospirillum lipoferum,
Azospirillum brasilence, Bacillus megaterium, and
Pseudomonas.E)Elemental sulfur :Elemental sulfur can be added as a
mineral additive to facilitate rapid decomposition.
Maturity of Compost
Maturity is the degree or level of completeness of the composting process.
For mature compost, raw starting materials (feedstocks) have been
sufficiently decomposed to produce a stable product.Stability refers to a
specific stage or decomposition
Compost is considered mature when it has cooled, turned a rich brown
color, and broken down into small, soil-like particles. It can take
anywhere from two weeks to two years for compost to reach maturity,
depending on the materials used, the size of the pile, and how often it's
turned. Larger quantities of material tend to compost more efficiently.
COMPOSTING SCENARIO
Approximately 4.86 million tons of solid waste is produced in urban areas of
Bangladesh each year, where organic fraction covers about 75% - 85%
(Aminul, 2005). Despite its potential reuse value, from this large volume,
only 2% of the total organic wastes are recycled and composted to organic
fertilizers (Kabir, 2015).
Composting can face a number of challenges, including:
1) Composting the wrong materials: Adding the wrong materials to
your compost can cause foul odors, diseases, and insects.
2) Pests: Composting can attract pests like rodents and insects. To
reduce the risk of pests, you can choose a compost bin with a tight-
fitting lid and place it in a well-lit area.
3) Pile too dry: Adding too many dry materials like sawdust,
cardboard, or dry leaves can cause the compost pile to become too dry.
This can stop the decomposition process from working effectively.
4)Contamination: Regular garbage is the most common contaminant in
municipal composting programs. Separating the garbage from the
compost is messy and inefficient.
5)Lack of space: In the culinary industry, a lack of space and
equipment can make it difficult to store, sort, and process food
waste.
6) Compost quality: The quality of compost depends on its
ingredients.
7) Slow process: Composting is a slow process.
8) Spread diseases: Composting can spread diseases.
·9) Damaging components: Compost can contain damaging
components.
Isolation of Azospirillum:
The bacteria are wide spread in soil and occur outside as well as inside
the roots. Enrichment procedures are necessary to obtain cultures of the
organisms from plant roots as well as soil samples.

Small pieces of washed roots (0.5cm.) or small soil samples (few µg) are
placed on a semi solid agar medium containing sodium malate or
calcium malate as the carbon source. It is incubated at 28 – 30° C in an
incubator. After two days pellicles of Azospirillum can be seen 1 - 2 mm
below the upper surface of the medium. Usually screw cap bottles are
used for isolation of the organisms by the enrichment method.

On the semi solid malate medium white, dense and undulating fine
pellicles are found which indicate the Azospirillumare present. For
obtaining pure culture several subculturing is necessary.
Identification or Authentication of Azospirillum:
Several methods are followed for identification of Azospirillum-
1. Microscopic examination: Under microscope the cells have one
half spiral turn and show spirillar movement. By gram staining it will
be found as gram negative.
2. Nitrate reducer: Azospirillum is capable of reduce nitrate and
denitrify.
3. Viability count: In this method the viability of the organisms in the
medium could be done by plating dilutions of the carrier (FYM and
soil) on ammonium chloride containing agar medium (Okon, et. al.
1977).On this medium it is possible to count the number of
Azospirillum cells at a given time.
Cellulolytic Microorganisms:
Cellulolytic microorganisms are those microorganisms, capable of
utilizing cellulose as their food and energy. In other words, cellulolytic
microorganisms are capable of breaking down cellulose.
In this context, it is necessary to have perfect knowledge about
cellulose. Cellulose is a carbohydrate in a long linear chain. Usually
the number of glucose units in a chain varies from 2,000 to 10,000.
Sometimes this may upto 15,000. The number of glucose units in
cellulose varies with respect to plant species.
Heterotrophic microorganisms such as fungi, bacteria and
actinomycetes are capable of decomposing cellulose. In humid soils
fungi are dominant microbes where as in arid and semi arid soils
bacteria and actinomycetes are dominant cellulolytic microbes. The
factors responsible for the population of fungi, bacteria and
actinomycetes are pH, soil moisture, temperature and organic matter
There is a good deal of evidence that the following
microorganisms are capable of utilizing cellulose:
Fungi Bacteria Actinomyces
1. Alternaria 1. Bacillus 1. Micromonosperma
2. Aspergillus 2. Clostridium 2. Nocardia
3. Fomes 3. Corynebacteriu 3. steptomyces
4. Fusarium m 4. Streptosporangium
5. Rhizopus 4. Cellulomonas 5. Microsphorangium
6. Rhizoctonia 5. Cytophaga
7. Trichoderma 6. sporocytophaga
8. Trichothecium 7. Vibrio
8. Psedomonas
Screenining and selection of Azolla suitable for use as Biofertilizer
General growth and viability: The collected species and strains should
at least grow under local climatic condition. The rate of growth of the
collected strains should be determined as various levels of different
growth to ascertain the better growing one. The growth factors are-

a) pH
b) Temperature
c) Salinity
d) Light
e) Mineral nutrients particularly “P”
f) Pest resistance
g) Disease resistance
Comparatively better growing one should be selected for use.
2.Rapid biomass production: Less doubling time i.e., more biomass
production within short period.
3.Greater nitrogen fixation: More rate of Nitrogen fixation.
4.Rapid decomposition: Lower C:N ratio i.e., quicker release of
nutrients.
5.Resistance to pest: Less prone to insect attack.
6.Resistance to disease: Less susceptible to disease.
7.Resistance to temperature: Must be tolerant to local high
temperature.

If a species or strains is found to superior to others in growth in

respect of above conditions can be selected as the suitable
inoculum for use as biofertilizer.
Carrier material:
Carrier materials are those materials in which the selected
microorganisms used for biofertilizer preparation can multiply and
survive for a certain period of a time and can be brought to the
farmers. e.g., Charcoal, Cowdung, Clay, Peat, Sawdust, Poultry
manure, Sewage sludge, Ash etc.
The carrier material must have the following criteria:
1.It should have good adjustability to microbes.
2.It should have high availability and cheap.
3.It should have high moisture holding capacity.
4.It should have carbon source and high nutrient content.
5.It should be free from toxic material.
6.It should have good adsorption capacity.
7. It should have high organic matter content.
8. It is easy to sterilize, handle, grind, and apply.
9. It should have adhered capacity to seed.
10. It should have neutral pH.
 Collection and Processing of Carrier Material:
a)Collection of carrier material (peat)
b)Drying of carrier material
c)Sieving of carrier material using 60 mesh sieve
Neutralization (add 2% CaCO3 to adjust pH at neutral condition)
 Application or Use of Rhizobial Biofertilizers:

1. Take weighted quantity of legume seeds in a

container/bowl/plastic pot/polybag.
2. Add sugarcane molasses (2-3% for large seeds viz. groundnut,
soybean etc. and 3-5% for small seeds viz. lentil, mungbean,
etc.) or gum acacia (40% solution) and mix with seeds to make
them sticky.
3. Add measured quantity of peat based inoculant (2-3% for large
seeds and 3-5% for small seeds) usually 20g/Kg seeds to sticky
seeds.
4. Mix seeds with inoculum until they are coated and appear
uniformly black.
5.Dry seeds under shade on a paper. Do not dry in direct
sunlight.
6. There should be a minimum 24 hours gap between seed
treatment with fungicide and biofertilizer application.
7. Use double quantity of biofertilizer in case of pesticide treated
seeds.
8. Sow the inoculated seeds and cover the seeds with soil
immediately.
Field Application of Blue Green Algal Biofertilizers:

1.Apply algal inoculants @ 10Kg/ha over standing water in the

field one week after transplantation. Addition of excess of algae
is not harmful rather it helps quick algal build up. Keep the field
flooded atleast for two days immediately after algal application.

2.Apply algae atleast for 3 to 4 consecutive seasons.

Follow the recommended pest control and other management
practices since they not interfere with algal growt
Recommendation:
1. If mineral nitrogenous fertilizers are not being used, apply blue
green algae in order to gain the benefit of 20-30Kg N/ha.
2. When mineral nitrogenous fertilizers are used reduce its dose
by 25Kg/ha and supplement with algal application.
3. Broadcast 8-10Kg soil based blue green algal inoculant over
every hectare of land.
Application of Azolla Biofertilizers:

Azolla is a free floating fern, fixes atmospheric nitrogen in

symbiosis with Anabaena azollae. Azolla can be used both as
a green manure and as a dual crop after transplanting
depending on water availability.

As a dual crop, inoculate Azolla in standing water @ 3-

4tons/ha 1-2 weeks after transplanting of rice. After 3-4
weeks, water needs to be drained out and azolla can be
buried in the soil where it is growing, with a weeder or other
suitable implement. Repeated incorporation of Azolla is
needed. Azolla can be grown more than once for the same
rice crop to get an additional benefit.
Application of Azotobacter Biofertilizers:
The various preparations of Azotobacterin may be applied in the
following ways:
a.Agar preparation: Growth from one Roux bottle or one 500ml. One
erlenmyer flask is sufficient to incubate seeds of cereals for sowing
one hectare of land; three bottles are required for potato tubers and
vegetable seedlings.
b.Peat preparation: 3Kg are used for treating cereals and 6kg for
potato tubers and vegetable seedlings (one gram preparation should
contain 5x107 cells).
c.Liquid preparation: 200ml. for treating cereals and 500ml. for
potato tubers and vegetable seedlings.

Usually seeds or seedlings are inoculated with the Azotobacterin

preparation. However, soil mixed cells may be spread on the soil surface
before ploughing under or may be sprayed when mixed with water.
Quality control of Biofertilizer

1. The general assessment in testing and selecting Rhizobial

strains.
2. Maintaining and issuing mother culture of chosen strains.
3. Checking the quantity of broth before use so that a minimum
of 10¹º Rhizobia per ml. broth is assured.
4. It may take 5-7 days to reach to the farmers. So it should be
kept in room temperature (20- 30 degree centigrade) for five
days and then should be counted to find the number. The
farmers should get and it should be at least 10
5.The inoculants should have maximum shelf of six months from
the date of its manufacture.
6.Any type of contamination should be avoided.
7.The pH of the inoculants should be between 6 and 7.5.
8.The inoculant should show effective nodulation on all those species/cultivars
listed on the packet before the expiry date. The total dry mass of inoculated
plants should be at least more than that the controls.
9.The inoculant should be carrier based and the carrier materials should be in
the form of powder. The peat-lignite, peat soil, humus or similar material should
be neutralized by CaCO3 and sterilized.
10.The manufacturers should control the quality of broth and maintain the
records of tests.
11.The inoculant should be packed in 50-75 µ low density polythene packet.
12.Each packet should be marked legibly to give the following information:
a.Name of the product,
b.Leguminous crops for which intended,
c.Name and address of the manufacturer,
d.Type of carrier,
e.Batch and code number,
 f. Date of manufacture,
g. Date of expiry,
h. Net quantity meant for 0.4 ha,
i. Storage instructions,
13. The above item should be printed on a colored ink background.
14. Each packet should be marked with the certification mark by the
organization.
15. The inoculant should be stored by the manufacturer at temperature of 15
degree centigrade and not exceeding 30 degree centigrade.
16. Tests should be carried out time to time.
 INTERACTIONS OF BIOFERTILIZERS WITH Pesticides

The following points must be considered regarding the interaction

of pesticides with Biofertilizer:
1. Recommended doses of pesticides generally do not interfere with the
establishment and activity of biofertilizer in soil.
2. Toxicity of pesticides seems to be higher in laboratory culture than that in
the field. As for example, 5ppm propanol prevents the growth and
nitrogen fixation by Anabaena cylindrical, Tolypothrix tennis, and Nostoc
endophytum. But the same concentration of this pesticide does not show
any effect on the growth and Nitrogen fixation of these organisms either
in sterilized or nonsterilized soil.
3.The rate of degradation of pesticides is more rapid in the soil than that in
the laboratory.
1. The effect of pesticides depends on the initial microbial population in the soil,
nutrient status of soil and mode of application of pesticides. As for example,
pentachlorophenol does not show any effect when incorporated in soil. But
when this pesticide is applied on the surface soil even at low concentration, it
inhibits growth and nitrogen fixation by biofertilizer.
Interaction of pesticides with BiofertilizerS:
The effect of pesticides on biofertilizer can be stated under the following
subheadings:

A.Inhibitory effects: This type of effect depend on 1) types of pesticides, 2) doses of

pesticides, 3) mode of application of pesticides, and 4) kinds of strain used for the
production of biofertilizer. As for example, dose of some pesticides may vary from
100-1000 ppm to inhibit the growth and nitrogen fixation of microorganisms.
B.Selective effects: There are some pesticides which have particular effects on
particular strains of microorganisms. Some pesticides are toxic to certain strains,
but they may have no effect to other strains.
C.Stimulatory effects: Among the pesticides, insecticides have stimulatory effects in
the activity of biofertilizer. It is an indirect effect. Insecticides destroy the insects
which feed on cyanobacteria. This insecticide stimulates the growth of blue green
algae.