1. Guided by Dr.Sunita Adhikari, Assistant Professor, Dept. of FT, GNIT Page 1
Food Waste Management and Recycle
Sruti Mandal (Author)
Department of Food Technology
Guru Nanak Institute of Technology
Kolkata, India
srutimandal94@gmail.com
Arunima Mukherjee (Author)
Department of Food Technology
Guru Nanak Institute of Technology
Kolkata, India
arunimakly@gmail.com
Abstract—The project “Food Waste Management and
Recycle” is connected to the discussion on the causes, remedy and
innovations on the high amount of food waste generated. The
discussion is focused on recycling the food wastes to convert it in
value added by- products. Food wastes mostly ends up rotting in
landfills, thereby releasing greenhouse gases. This project
includes some food waste management strategies and methods of
recycling (biofuel, composite etc.). The environmental impact due
to food waste generation and also due to recycle of food waste is
discussed. It also includes the opportunities and disadvantages
about this issue.
Keywords—Food waste, recycle, waste management, greenhouse
gases
I. INTRODUCTION
During the last century, there has been a growing
deterioration of the environment due to rapid industrialization
of human production. In addition, the dependence of countries
on imported fossil fuels has meant that satisfaction of their
energy needs is not assured. These considerations made the
discovery of renewable fuels—which will be based on
national resources—one of the most important priorities for
most countries worldwide.
The disposal of large amounts of such waste can be a
challenge, and cause severe environmental issues when used
in landfill sites—such as uncontrolled gas emissions that
contribute to the greenhouse effect, and contamination of
water underground. It has been estimated that approximately
125 m3 of gas is produced from each ton of food waste that is
used for landfill, with an average composition of 60%–65%
methane and 35%–40% CO2, which is responsible for 8% of
the total anthropogenic methane emissions. In many Asian
countries, landfill and open dumping of food waste represent a
large proportion of waste treatment methods. Other practices
of food waste utilization, such as feeding animals, have raised
serious hygiene-related issues and the use of themas fertilizers
can cause severe pollution of water. Incineration is also a
waste treatment method used for food waste.
On the other hand, the rich composition of food waste—in
carbohydrates, proteins, and minerals—makes it an excellent
raw material for the production of biofuels and bio-based
chemicals through microbial conversion. The advantage of
this “alternative” use of food waste is not only to solve the
“food versus fuel” dilemma and exploitation of low-cost raw
materials for the production of biofuels and chemicals; it
would also lead to a decrease in the use of landfill areas,
minimizing greenhouse gas emissions and improving land use.
Another interesting use of food waste is as a raw material
for the production of different kinds of enzymes. The rich and
diverse composition of food wastes—which includes proteins,
starch, insoluble carbohydrates, and lipids—can facilitate the
production of a diverse range of enzymes. Some characteristic
categories of enzymes that have already been produced from
food wastes are amylases, proteases, ligninocellulolytic
enzymes, lipases, and pectinolytic enzymes.
II. BIOFUEL
Since food waste is considered zero cost material it is
possible to develop cost-effective commercial methods for the
production of biofuel using lipid and carbohydrate generated
from food waste. Research on the conversion of food waste
into biofuel provides an innovative food valorization strategy;
which could contribute substantially to bio-based
economy. Biogas production is a well-established biological
process regarding production of biofuels from food wastes
Food waste is a well-known nonedible source of lipids,
carbohydrates, amino acids and phosphates. Research reveals
that bakery and mixed food wastes contain significant amount
of lipids and carbohydrates. Depending on the source of food
waste the average lipid content is around 30% and the average
carbohydrate content is around 50% .Different types of food
wastes can be hydrolyzed enzymatically to produce food
hydrolysate and lipids .The food hydrolysate is rich in
carbohydrate and can be used for the production of bioethanol;
whereas, the obtained lipid can be converted to biodiesel.
A. Production of bioethanol
Ethanol is an excellent candidate to replace gasoline, and it
has traditionally been produced mainly from sugars or starch.
The use of sugars and starch as raw materials for ethanol
production had a negative effect on their availability as human
food, which raised their prices globally and increased concern
about the ethics of biofuel production. This resulted in a
change of focus to the use of renewable raw materials such as
lignocellulosic biomass and waste. The use of wastes as raw
materials for the production of biofuels not only prevents the
“food versus fuel” dilemma; it also counteracts accumulation
of these wastes in the environment.
Production of ethanol fuel from food waste is carried out
with the singular aim of converting the waste to useful

2. Guided by Dr.Sunita Adhikari, Assistant Professor, Dept. of FT, GNIT Page 2
material. To achieve this, the conversion of food waste
(maize) is carried out via microbial hydrolysis, which yields
63% fermentable sugar wort. This is then converted into
ethanol by fermentation process using Saccharomyces
ceverisiae. 95% ethanol is obtained by fractional distillation of
the fermentable wort. The percentage fermentable sugar yield
from the biomasses in study, it is more economical to produce
ethanol from food waste (maize) than old organic waste (old
newspaper).It is best to use food waste (maize) which gives a
higher percentage of fermentable sugar.
The total volume of ethanol produced from 2.5 kg of
organic and food waste was 0.86 litres. As reported in
literature by Mathewson (1980), that 1000 kg of 40% - 60%
fermentable sugar substrate can produce 265-378litres of
ethanol. This means that substrate of 2.5 kg, and containing
40% - 60% fermentable sugar can produce a maximum
ethanol yield of about 0.93 litres and a minimum yield of 0.65
litres. The experimental yield of 0.86 litres of ethanol from 2.5
kg of organic and food waste is well within acceptable range.
The experimental results obtained in this work shows that both
the conversion and fermentation processes were optimal [1].
B. Production of biodiesel
Edible vegetable oils such as canola, soybean, and corn
have been used for biodiesel production and are proven diesel
substitutes. However, a major obstacle in the
commercialization of biodiesel production from edible
vegetable oils is their high production cost, which is due to the
demand for human consumption. Reducing the cost of the
feedstock is necessary for biodiesel’s long term commercial
viability. Waste cooking oil (WCO), which is much less
expensive than edible vegetable oil, is a promising alternative
to edible vegetable oil. Waste cooking oil and fats set forth
significant disposal problems in many parts of the world. This
environmentally-threatening problem could be turned into
both economical and environmental benefit by proper
utilization and management of waste cooking oil as a fuel
substitute. Biodiesel is derived from fats and oils either by
chemical or bio-chemical means. There are at least four ways
in which oils and fats can be converted into biodiesel, namely,
trans esterification, blending, micro-emulsions and pyrolysis.
Among these, trans esterification is the most commonly used
method as it reduces the viscosity of oil. Biodiesel production
by trans esterification reaction can be catalyzed with alkali,
acidic or enzymatic catalysts. Alkali and acid trans
esterification processes require less reaction time with reduced
processing costs as compared to the enzyme catalyst process.
A 95% of biodiesel is obtained when calcium ethoxide
catalyst (CETCAT) catalyzed waste cooking oil with presence
of methanol. Besides exhibits an excellent catalytic activity,
the CETCAT also very cost effective, easily prepared, can be
recycle and possesses high stability towards chemical
poisoning effects.
The experimental results in this study show high yield of
biodiesel (95 %) produced through trans esterification reaction
using calcium ethoxide catalyst with methanol at 70°C for 2
hoursreaction. It’s revealed that calciumethoxide has excellent
catalytic activity and also high in stability because the catalyst
can be reused for a several time without reduce their
performance drastically. Biodiesel produced using this method
is expected to have a high octane number, which is suit for use
in conventional diesel engine without further purification [2].
III. COMPOSTING
Composting is the biological breakdown of biomass by
microorganisms which occurs in the presence of air. The
process generally takes up to 6 months (including the
maturation phase) and gives up to a 50% reduction in quantity
of material. The end products of composting are carbon
dioxide and a solid organic fertilizer.
Composting provides possibly the simplest option for
treatment of food waste and the composting industry is
currently growing rapidly with the increase in separate
collections of green and food waste.
An alternative process for treating domestic food waste is
home composting which has additional benefits of not
incurring transport costs or emissions. For this reason home
composting, where possible, is a preferred treatment method
for domestic biodegradable waste. However, very simple
compost pile systems don’t consistently provide a high quality
product and if not adequately managed can develop into an
anaerobic system with the resulting methane emissions.
Additionally home composting is not recommended for
treatment of meat and cooked foods due to the potential risks
of odor problems and attracting vermin.
IV. ANAEROBIC DIGESTION
AD is similar to composting in that biodegradable
materials are broken down naturally by micro-organisms.
However, the anaerobic process generates a mixture of carbon
dioxide and methane (known as biogas) which can be used as
a valuable source of renewable energy. There is considerable
variation in AD processes for example the process may by
classed mesophilic or thermophilic depending on the
temperature at which it operates. Thermophilic processes take
place at about 55°C and proceed more rapidly than lower
temperature mesohphilic processes at about 35°C.
Thermophilic processes can give higher yields of biogas and
result in a smaller footprint of plant. On the negative side, the
process can be less stable due to the limited range of
thermophilic microorganisms and also requires consider
energy input to maintain the temperature. Moisture content of
the feedstock can also affect the type of technology used with
feedstocks of <15% dry solids being classified as wet
processes and those with between 15-40% dry solids as dry
processes.
In some ways AD is a more suitable technology for
treatment of food waste than composting as the high moisture
content of food (usually about 75%) make it a good
composition for this technology. Food is also a comparatively
high energy feedstock and therefore results in higher energy
generation than other feedstock such as animal manure.
However food waste does require a heat treatment stage in
order to comply with the animal byproducts regulations. This
can be achieved within the AD process if operating under
thermophilic conditions (requires 57°C for 5h) but under
mesophilic conditions requires a separate treatment stage
either pre or post digestion. This technology is well exploited

3. Guided by Dr.Sunita Adhikari, Assistant Professor, Dept. of FT, GNIT Page 3
in many European countries and rapidly growing in the UK
with over 214 facilities with an overall capacity to process
more than 5 million tons of material per annum, and a total
installed generating capacity of over 170MW of electricity
V. UTILIZATION OF WHEY FROM DAIRY
PRODUCTS
Annually, approximately 1.2 million tons of lactose and
200,000 tons of milk protein are transferred into whey
worldwide, of which less than 60% are utilized for human
food and animal feed. Thus, a nutritionally valuable food
resource is wasted. Some progress has been made in utilizing
whey, whey solids, and whey protein concentrates in the
manufacture of dairy, bakery, and specialized products.
However, the potential of whey and whey derivatives is not
being fully utilized.
In particular, various avenues of utilizing lactose
are open. These possibilities include
• The conversion of lactose into glucose, galactose and
fructose to improve its sweetening power production of
alcohol from lactose
• Production of single cell proteins from lactose
• Synthesis of gums from dairy products.
• The use of whey proteins to replace non-fat dry milk and
casein would require an improvement in their water absorption
property.
There is a great potential to produce long shelf-life whey-
based drinks, but little progress has been made in the
widespread commercialization of such products. A need does
exist to improve the functional properties of whey proteins.
Aside from the development of new processes and products,
there is also a great need to economize and commercialize
newly developed technology [3].
VI. UTILIZATION OF ORANGE PEEL FROM
ORANGE JUICE MANUFACTURING UNITS
Industrial extraction of orange juice produces a large
amount of solid wastes, mainly orange peel, which is about
45-60% of the original weight of oranges. Those wastes are
considered as an ecological problem, because they are dumped
on the land around the factories where they putrefy.
The orange peels can be used for the production of
following products:
 Citric acid production from orange peel waste by solid
state fermentation of Aspergillus niger.
 To recover pectin. The % yield of pectin was found to
be22.4% on wet basis and 21.3% on dry basis.
 Steam distillation of orange peel was used to extract
essential oils
 Essential oils were used in food industries as natural
flavor, fragrances and natural food colour and essence.
 The essential oil if mixed with kerosene in the ratio 1:3
and the mixture was saturated with camphor; a very potential
insecticide is produced.
 The dried orange peel from steam distillation was used up
as animal fodder [4].
VII. COFFEE BY PRODUCT UTILIZATION
In coffee producing countries, coffee wastes and by-
products constitute a source of severe contamination and a
serious environmental problem. For this reason, since the
middle of the last century, efforts have been made to develop
methods for its utilization.
Coffee by-products and wastes can be used in a variety of
ways, some of which are summarized here:
Biogas from coffee waste water: The water drained from
coffee cherry extract is another potential source of biogas
production.
 Coffee Pulp Solids to Silage: Coffee pulp is really a very
versatile substance, but the presence of caffeine has up to now
been seen as a negative factor making it unusable as an animal
foodstuff. By a slight dewatering of the pulp, inoculation with
commercial silage additives and packing it into plastic liners
within FIBCs [Recycling container], or one tone flexible bulk
containers, within 3-4 months an excellent foodstuff suitable
for cattle feedlots is achievable, bringing extra cash flow
during the off season period.
 Mushrooms: In contrast to the larger scale operations
required for waste water treatment and silage making, coffee
pulp can also be handled on the small-scale family level
operation with ease. The fermented and partially dried, pulp
can be used as a substrate for growing exotic mushrooms.
 Unrefined pectins: These pectins can be either thermo
reversible soluble gels or non reversible cross linked ones
which have a different mouth feel.
 Natural coffee fruit sugars, mainly from the recycled
pulping water: They are mostly monosaccharides, glucose,
galactose, rhamnose and arabinose, with a different flavour,
reminiscent of plums, and could be marketed as something
new for the more sophisticated coffee connoisseur.
 Antioxidants and Flavonoid compounds: These are
mainly the anthocyanin fruit colour compounds, but they also
contain all the other polyphenolics such as chlorogenic acids
and of course caffeine. These materials can be put together
into several combinations to make a range of food additives
which should be of interest to the ‘health food’ industry.
 Colorless Pro anthocyanin: as a resource base for other
food manufacture or perhaps the more sophisticated synthesis
of other chemicals [5].

4. Guided by Dr.Sunita Adhikari, Assistant Professor, Dept. of FT, GNIT Page 4
VIII. DISADVANTAGES
 Use of food wastes presents some challenges, such as the
difficulty in separating them from the whole waste mass and
their easy degradability.
 The rich composition of food wastes makes them easily
contaminated by various microorganisms, which makes their
storage and handling a considerable challenge.
 The high water content of food wastes results in high
volumes—which must be stored and transferred. These
properties lead to difficulties in storage and a requirement for
large cooling units, which in turn have a negative impact on
the cost of the raw material and its availability.
XI. CONCLUSION
Most people tend not to think of food wastes as having an
adverse impact on the environment because it is
biodegradable. However, most food wastes end up in landfill
where they create methane, a greenhouse gas with 21 times the
warming potential of carbon dioxide (CO2). Wasted food also
wastes the energy, water, money and resources used to
produce, process, store and transport the food
The benefits of recycling food waste are clear, increased
energy production, lower carbon emissions, and lower space
requirements for landfills. Although the introductory costs are
high, various food production companies are beginning to see
the long term benefits of implementing recycling
infrastructures in their plants.
Surely a nation cannot satisfy all of its energy needs
through food waste generated biofuels. However, the benefits
are significant and the alternative comes at a cost to the
environment that is unnecessary.
ACKNOWLEDGMENT
We acknowledge the Department of Food Technology,
GNIT for giving us the opportunity to present this paper.
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