treatment methods and potential uses of vegetable waste

1. Presented by
Kulwinder Kaur

2. Overview
This presentation reviews the three areas of waste management in
vegetable‐processing operations:
(1) waste generation;
(2) waste management and treatment; and
(3) value‐added utilization of vegetable wastess

3. • India is the second largest producer of the fruits (97.97 million tonnes)
and vegetables (183.17 million tonnes) in the world during 2019-20,
has been bestowed with wide range of climate and physio-
geographical conditions.
• Fruits and vegetables account for the largest portion of that wastage.
• About 30 % of the fruits and vegetables grown in India get wasted
annually due to lack of proper cold storage infrastructure which is a
cause of concern.
(Source: https://www.freshplaza.com/article/9184270/indian-horticulture-output-to-
be-313-million-tons-in-2019-20/).

4. • Vegetable waste is a biodegradable material generated in large quantities,
much of which is dumped on land to rot in the open, which not only emits a
foul odor, but also creates a big nuisance by attracting birds, rats, and
pigs—vectors of various diseases.
• Vegetable wastes include the rotten, peels, shells, and scraped portions of
vegetables or slurries.

5. Production exceeds demand
Premature harvesting
Strict quality standards of processing and marketing
Poor postharvest handling and storage infrastructure
Chemical abuse for shelflife extension of produce
Lack of processing facilities
Wide range of processed product

6. Life cycle of waste generation from vegetables

8. Water
pollution
Solid or liquid waste
pollutes
aquatic life in rivers, lakes,
and sea
Soil pollution Solid waste Undesirable changes in soil
composition
Air pollution Malodorous compounds in
air
Unhygienic
conditions
Breeding of pathogenic
microbes, flies,
mosquitoes and rodents
Unhealthy environment and
spread of an epidemic
Aesthetics Solid waste Loss of aesthetic value of an
area

9. The objective of any waste management plan and strategy should be twofold:
(1) minimization of waste; and (2) selection of appropriate waste treatment
and/or disposal strategies.
The definition of waste minimization include three elements:
(1) preventing and/or reducing the generation of waste at source;
(2) improving the quality of the waste generated, such as reducing the hazard;
and
(3) encouraging reuse, recycling, and recovery.

10. Characterization of
waste
Flow
measurement of
waste
Segregation of
highly
contaminated
waste
Reduction,
Reuse and
recycling
Treatment and
disposal of
waste

11. Physically
• Moisture
• Weight
• Temperature
• Colour
• Total solids
• ash
Chemically
• cellulose,
• hemicellulose,
• starch,
• Reducing sugars,
• protein,
• Total organic
components
• BOD,COD,
• pH, and toxic metal
Biologically
• Presence of
organism and
pathogens
Characterization of waste:
• It is essential for deciding its application and determination of economic feasibility
of the process as waste may contain materials that are hazardous or potentially
hazardous to public health.

12. Flow measurements of waste
Determine the volume of solid and liquid waste generated daily and annually.
Segregation of highly contaminated waste:
This initial determination is important because the volume of wastewaters
requiring treatment determines the size of the treatment plant.
Reduce
Minimize solid waste production.
Recover
Reclaim waste utilization to produce byproducts/coproducts (e.g.,
nonfermented and fermented products).

13. Recycle
The solid waste from vegetable processing contains nutrients that can be
used as animal feed, bioenergy, and compost.
Dispose
There will always be some waste that would have no further use and
thus will need to be disposed of away from the factory premises.

14. Existing Methods
• composting,
• landfill,
• Incineration or combustion, gasification , pyrolysis and
• Animal feed.
Note: They are universally applicable but are wasteful of resources–
neither recovers energy particularly efficiently.

15. • Vegetable processing, packing, distribution and consumption generate a
huge quantity of waste that is usually disposed of either by composting or
dumping into landfills/rivers, causing environmental pollution.
• Such resources can act as an excellent source of nutrients due to enrichment
of functional compounds, such as polyphenolics, carotenoids and dietary
fibre.
• This has potential to be used in the production of animal feeds especially for
cattle and dairy cows, and processing the waste into silage.

16. Landfill is the most economical, though not always
environmentally safe, way of disposal where the waste is
buried into the earth.
In landfills, main macronutrients present in organic matter
are hydrolyzed to soluble products and finally to biogas
through methanogenesis.
Application: production of electricity, hot water, and steam as an energy source
Disadvantages
• Traditional landfills were not managed in a scientific way.
• Landfill gases pollute the air and cause greenhouse effect,
• Leachate contaminates the ground water.
Land Filling

17. Applications
To preheat air and to power generation
Ash can be used as construction material
Drawbacks:
• Higher investment and operational costs
• Atmospheric Air pollution
• Low calorific content
• It is the controlled burning of waste at high temperatures in a facility designed for efficient and
complete combustion (Rhyner et al. 1995).
• This process generates carbon dioxide, water, sulfur dioxide, ash, gases, and heat energy.

18. • The feasible alternative option to deal with the
solid vegetable waste is to convert it into high-
density briquettes, which give flexibility in
storage, transportation as well as the use as per
requirement.
• Briquetting of waste biomass can be done by
bringing its moisture content to the specific
level, pulverizing and mixing it with some kind of
binder or by direct compacting.
• The briquettes can be easily adopted for
gasification, pyrolysis and in other biomass-
based conversions (Kaliyan and Morey, 2009).
Briquetting

19. Physical and thermal properties of briquettes

20. • The gasification process breaks down the hydrocarbons left into a
syngas using a controlled amount of oxygen at elevated
temperatures 700°C.
• The gasification process occurs as the char reacts with carbon
dioxide and steam to produce carbon monoxide and hydrogen.
• Syngas may be burnt directly for heating and/or electricity production
or may be further converted to act as a substitute for almost any
fossil fuel.

22. • Gasification in
conjunction with gas
engines obtains
higher conversion
efficiency than
conventional fossil-
fuel energy
generation.
Advantages
• High temperatures
required to break
down any waste
containing carbon.
• Not economically
attractive.
Disadvantages

23. Thermal decomposition of organic
materials in an inert atmosphere or
with insufficient oxygen to cause
partial oxidation
Endothermic process
Involves the change of chemical
composition
Irreversible process
Pyrolysis

24. • Simple, inexpensive
technology and
environment friendly
• Reduce the country’s
dependence on
imported energy
resources by
generating energy
from domestic
resources
Advantages
• Ineffective in
destroying and
physical separating
inorganic compound
from contaminated
medium.
• Requires proper
treatment, storage and
disposal of hazardous
wastes.
Disadvantages
Pyrolysis

25. • Composting is an old and inexpensive
method that converts organic waste into
useful compost that can be used as a soil
conditioner and organic fertilizer.
• It is an exothermic biodegradation process
that involves a complex web of bio-
chemical reactions in which facultative and
aerobic micro- organisms catabolize
substrates to produce carbon dioxide (CO2)
and heat, and finally transformed into stable
composts

26. Novel or Emerging technologies
• Even though the above- described conventional techniques for
managing food wastes have improved in recent years, only a little
fraction of the residues generated can be valorized in some way
(Luque and Clark, 2013)

27. Fluidized bed combustion
• Fluidized bed combustors can be designed to combust almost any solid, semisolid
or liquid fuel without the use of supplemental fuel, as long as the heating value is
sufficient to heat up the fuel, drive off the moisture and preheat the combustion air.
• Wastes can also be co-fired with coal in many existing coal-fired fluidized bed
combustion boilers.
Advantages:
• compact furnace,
• simple design,
• effective burning of a wide variety of fuels,
• relatively uniform temperature
• reduced emission of nitrogen oxide and sulfur dioxide gases

28. Fluidized bed combustors

29. The combustion of three high moisture content waste materials (olive oil waste, municipal
solid waste and potato) in a fluidized bed combustor was investigated by Suksankraisorn et
al. (2003) and a comparison with co-firing of these materials with coal in the same
combustor has been made.

30. Anaerobic Digestion
Since the all stages of anaerobic digestion are
controlled by bacteria, the product form varies with
the type of bacterial population.

31.  Increased reaction rates
 Less capital cost as a result of smaller
digester size
 Highly efficient technologies for anaerobic
digestion of FVW
 High stability, a high depuration rate and
energy recovery with a good process
economy
 Significant biogas productivity and better
effluent quality from fruit and vegetable
wastes anaerobic digestion
 Rapid acidification of fruit and vegetable
wastes decreasing the pH in the reactor
 Larger volatile fatty acids production (VFA),
which Stress and inhibit the activity of
methanogenic bacteria
 Depression of the overall performance of the
reactor by increasing the feed concentration

32. Biodiesel production
• By transesterification of vegetable oils with simple alcohols either using a
catalyst or without it.
• By the fermentation of carbohydrate plants (sugar or starch based
vegetable waste such as sugarbeet or potato peel ).
• Reaction temperature, alcohol to oil ratio, mixing speed, and purity of
reactants are the other parameters which influence biodiesel production

34.  Conversion of waste palm oil by
transesterification to produce ethyl
esters gives a product comparable to
applying the process to neat VOs with
properties comparable to those of the
local diesel fuel
 Emission of less pollutants by biodiesel
production
 Deterioration of biodiesel combustion
performance at the higher energy input
due to its high viscosity, density and low
volatility

35. Vermicomposting
Advantages:
• Rapid and Economical
• Environment friendly
• End product is disinfected and detoxified
• Vermicomposting technology, the bioconversion of organic waste into a biofertilizer
through earthworm activity, is globally becoming a popular solid waste management
technique (Manyuchi et al., 2013; Thamaraj et al., 2011).
• The earthworms feed on the vegetable waste and their gut acts as a bioreactor whereby the
vermicasts are produced.

36. Bioactive compound
from vegetable waste

39. • Waste management in vegetable production is a tough problem and its
optimum solution must foresee local factors to be taken into account.
• Waste treatment methods were divided in two categories : the currently
employed and the novel ones.
• Although novel methods (bio active compound extraction, biofuel
production etc) appear to be promising and attractive alternatives, handicaps
like high cost, requirements for trained personnel and high capital
investment are still holding them back from widespread application in the
vegetable waste industry.