The document discusses fruit and vegetable waste (FWV) management, highlighting the significant quantities of FWV generated in India and various management techniques such as anaerobic digestion, composting, and biodiesel production. It outlines anaerobic digestion stages, conditions for optimal biogas production, and the potential for energy generation from FWV. Additionally, it explores the utilization of apple pomace and citrus wastes for value-added products, enhancing economic benefits in waste management.

1. FRUIT WASTE
MANAGEMENT
MOKSHA CHIB AMEYA PATHAK
13FET1003 13FET1004

2. INTRODUCTION
• Fruit and vegetable wastes (FVW) are produced in large quantities in markets and
constitute a source of nuisance in municipal landfills because of their high
biodegradability (Misi and Forster, 2002).
• In India, FVW constitute about 5.6 million tonnes annually and currently these
wastes are disposed of by dumping on the outskirts of cities (Srilatha et al., 1995).
• Among the several processes that are being used nowadays, the ones described
are the following: thermal processes, evaporation, membrane processes, anaerobic
digestion, anaerobic co-digestion, biodiesel production, combustion, supercritical
and subcritical fluid extraction, coagulation and composting

3. ANAEROBIC DIGESTION
• Anaerobic digestion progresses in four stages.
• The first stage is known as Hydrolysis where complex organic materials in solid
forms are broken down by external enzymes into soluble forms.
• C6H10O5 + H2O C6H12O6
• C6H12O6 +6H20 6CO2 +12H2
• The second stage is Acidogenesis where the bacteria produce volatile fatty acids
such as acetic acid, propionic acid, butyric acids, ethanol and others. Carbon dioxide
and hydrogen will also be liberated in this stage.
• C12H22O11 + 9H20 4CH3COO-
+ 4HCO3
-
+8H+
+8H2
• C12H22O11 + 5H20 2CH3CH2CH2COO-
+ 4HCO3
-
+6H+
+ 4H2
•

4. ANAEROBIC DIGESTION
• The third stage is Acetogenesis. H2, CO2 and NH3 are by-products in this stage.
• CH3CH2COO-
+H+
+2H20 CH3COO-
+H+
+ CO2 + 3H2
• Methanogenesis is the last stage, where the methanogenic bacteria utilize products of the second stage and
convert them into methane.
• CH3COO-
+ H+
CH4 + CO2
• CO2 + 4H2 CH4 + 2H20

5. ANAEROBIC DIGESTION
• Most fruits and vegetables processed on seasonal basis and the wastes that emanate during these processes
vary considerably in their physico-chemical characteristics.
• Some of them are rich in toxic constituents such as limonin in citrus wastes.
• Most of them are deficient in nitrogen (such as mango and pineapple processing wastes).
• Overall potential for energy production through anaerobic digestion from these wastes is large.
• A digester is used for the fermentation process.
• It consists of a mixing tank, sludge tank, an engine generator set and liquid storage. The digester is an in-ground
concrete tank and coated by epoxy.
• When gas production has ceased, the digester is emptied and refilled with a new batch.
• The retention time in the digester is 28–35 days.
• In the first week, biogas was generated more slowly, but the yield was still released slowly until the end of the
fermentation phase.

6. ANAEROBIC DIGESTION
• Amongst the four stages, hydrolysis is the rate limiting stage for FVW. (Das & Mondal, 2013)
• Efficient digestion occurs at a pH near neutrality; the pH value was 6.0–8.0. (Ngoc and Schnitzer, 2009)
• C/N ratios between 20 and 30 are optimum for maximum biogas generation (Vishwanath & Nand, 1992)
• Experiments were performed at the lab scale, it was shown that biogas yield increased with slurry concentration
and use of catalysts (Aluminium oxide and Iron oxide being the best ones). (Das & Mondal, 2013)
• As rate of growth of microorganisms increases with increasing temperature within mesophilic range so rate of
biomethane conversion increases with microbial growth. It was observed that it was highest at 37°C. (Das &
Mondal, 2013)
• Biogas produced from the fermentation can be combusted for production requirements and lighting during the
production processes. Gas of this quality can be used to generate electricity.
• It may be used as fuel for a boiler, space heater or refrigeration equipment, or it may be directly combusted as a
cooking, lighting, and fuel demand.
• The separated liquids amd solids not converted to methane are used as fertilizers.

8. COMPOSTING
• Compost can act as an effective surface mulch, increase the concentration of soil organic matter, improve tilth
and water holding capacity, suppress weeds and provide a long-term supply of nutrients as the organic material
decomposes (Ozores-Hampton and Obreza, 1999; Evanylo and Daniels, 1999).
• For these reasons, composting has been advocated as one component of sustainable agriculture (Edwards et
al., 2000).
• Maintaining predictable compost quality is a particular problem when the material is produced from sources such
as municipal solid waste (MSW), pulp mill solids or feedlot waste as a means of reducing an organic waste
stream. In these operations, the process must be optimized for both efficiency of waste disposal and quality of
end product, which demands that some compromise be made in both.
• Organic matter is converted by composting into a stable substance which can be handled, stored, transported
and applied to the field without having adverse effects to the environment.
• Proper composting effectively destroys pathogens and weed seeds through the metabolic heat generated by the
microorganisms. Such composts are not suitable as fertilizers or soil conditioners but can suppress pathogens.

9. COMPOSTING
• Nevens and Reheul (2003) combined an average yearly cattle slurry application (about 40 Mg/ha) and added a
moderate yearly vegetable and fruit waste (VF) compost application (22.5 Mg/ha).
• The compost effect on silage maize DM yield and N uptake was studied and the possible saving of additional
mineral N owing to the slurry and/or compost application was determined.
• The amounts of residual mineral soil N were also measured to estimate the possible threats of compost and/or
slurry use for excessive nitrate leaching.
• Silage maize N uptake and N concentration in maize were higher when compost was applied.
• Despite the low N output/input rate with compost application, it did not result in an excessive amount of residual
soil nitrate-N, provided that the additional mineral fertilizer N was adapted to the economic optimum level.
• Compared to slurry application, 4 years of VF compost application resulted in significantly higher soil organic
matter and total nitrogen concentrations.

10. BIODIESEL PRODUCTION
Renewable, biodegradable, non-toxic, more favorable combustion emission profile like low emissions
of CO, PM & unburned hydrocarbons
• According to Bouallagui et al. (2005), FVW containing 8-18% TS, 86-92% TVS & about 75% biodegradable matter was
anaerobic-ally digested under two conditions:
1. Single- stage: 70-95% of organic matter to CH4
2. Two-stage (involving thermophilic liquefaction reactor & a mesophilic anaerobic filter): 95% solids were converted to CH4
• Gunaseelan (2004) studied the biochemical CH4 potential of 54 fruits & vegetable waste samples & found:
1. The ultimate CH4 yields (B0) & CH4 production rate of fruit wastes ranged from 0.18-0.732 l/g volatile solids (TVS) added
and 0.016-0.122 per day respectively
2. Temp. had no effect on the B0 of mango peels, but the conversion kinetics was higher at 35˚C than at 28˚C
3. All samples gave monophasic curves of CH4 production
4. Different fruit parts within the same variety showed different yields in orange
pomegranate, grape vine and sapota
5. CH4 yields from mango peels, orange wastes, pomegranate rotten seeds & lemon
pressings were significantly higher than the cellulose

11. FLUIDIZED BED COMBUSTION (BFBC)
• Practically burns waste combinations into low emissions
• PROS: Compact & simple design, effective burning, uniform
temperature (750-900 ˚C), ability to reduce off emissions like
SO2 & NOx
• Fruit Waste: Fruit stones for which the moisture content is
very low & has no Cl
•They have high calorific values (LHV) similar to wood due to
the high lignin content, e.g LHV of apricot & peach stones are
about 20,000kJ/kg
• Parts of the combustor: BFBC column, distributor plate, one
fuel feeding pipe, overflow pipes, thermocouples, manometers
(to measure the pressure drop), screw feeder, fuel hopper for
fuel storage, natural gas supply & a cyclone for fly-ash removal

12. ENSILING
• Ensiling has been used to feed lactating dairy sheep as described by Volanis et al. (2004).
• Seven tons of non-marketable ripe oranges (Citrus sinensis) were coarsely sliced using a modified machine
meant for chopping whole plant maize and mixed with agro-industrial by-products and hay.
• The percentage composition of the ingredients in the ensiled orange mixture consists of orange slices, soybean
meal, wheat bran, cottonseed cake, salt, calcium phosphate and oat hey.
• The silage was made in a trench silo approximately 1 m high, coated with a plastic sheet.
• After filling the silo, the mass was air-tight closed with a plastic sheet and covered with soil to secure anaerobic
conditions for fermentation and to protect the silage from being exposed to solar radiation.
• After 30 days, the silo was opened and sampling was performed for chemical and microbiological analyses.
• Bulk samples were taken from two depths on a vertical section of the silage mass to obtain an indication of
differences in composition between the top and bottom of the filled silo.

13. WASTEWATER TREATMENT SYSTEM
The citrus processing operations discharge 450m3/day & generate a substantial amount of waste water that
is characterized by a high organic content, high strength COD (9500 mg/l) , BOD (7500 mg/l) and TSS of
15000 mg/l at temperature of 30-40˚C. (Ngoc et al (2009))

14. WASTEWATER TREATMENT SYSTEM
Of 450m3/day – Clean water
350m3/day – Irrigation water
100m3/day – Used in Digester
UASB: Up-flow anaerobic sludge blanket Ngoc et al (2009)

15. BIOSORPTION
Biosorption is a property of certain types of inactive, dead, microbial biomass to bind and concentrate
heavy metals from even very dilute aqueous solutions.
• Biomass wastes alike pectic acid & alginic acid exhibit adsorption
behaviors for metal ions e.g. pectin-rich sugar-beet, apple pomace &
citrus peels
• The cationic exchange properties may be attributed to presence of
carboxylic & phenolic functional groups, which exist either in the
cellulosic matrix or in materials like hemicellulose & lignin
FRUIT WASTE AS BIOSORBENT HEAVY METALS ADSORBED REFERENCE
Dried Citrus peels (Pectin) Pb>Cu>Co>Ni>Zn>Cd Kartel et al. (1999)
Orange peels Ni> Cu, Pb, Zn, Cr Ajmal et al. (2000)
Grape fruit skin Hg, Pb, Zn Jumle et al. (2002)
Chemically treated apple residues Cu, Ni, Zn Maranon and Sastre (1991)
Adsorption gel of orange juice residue by cross-linking with
epichlorohydrine
Pb Yano et al. (2001)
Adsorption gel of orange juice residue Pb Dhakal et al. (2005)
Electrostatic Interaction
Chelation
Microprecipitation
Complexation
Ion Exchange
Physical & Chemical adsorption

16. BIOSORPTION
Advantages of Biosorption
• Low cost
• High efficiency
• Easy incineration of adsorption gels
• Minimization of chemical & biological sludge
•No additional nutrient requirement
• Regeneration of biosorbent
•Possibility of metal recovery
According to Schiewer et al. (2008):
• Citrus peels are found to be the most suitable for biosorption of Cd; due
to higher stability than apple residues & grape skins
• Metal uptake rate ↑ with ↓ in particle size due to mass transfer
limitations
• Metal uptake ↓ with ↓ing pH due to competition of protons for
binding to acidic sites

17. UTILISATION OF APPLE POMACE
APPLES
APPLES FOR JUICE
JUICE
POMACE
BROTH
CONCENTRATED
JUICE
COMMERCIALISED
JUICE
Selection
Cleaning
Squeezing
Pressing
Extraction
Clarification
Concentration
Transport
Standardization
Bioprocesses involving Apple Pomace:
o Pectin Extraction
o Cattle feed
o Production of enzymes
o Production of aroma compounds
o Nitrogen-enriched pomace
o Production of Ethanol
o Production of Organic Acids
o Production of Heteropolysaccharides
o Production of Biopolymers
o Production of edible mushrooms
o Production of Baker’s Yeast
o Production of pigments

18. UTILISATION OF APPLE POMACE
UTILISATION DETAILS REFERENCE
Pectin Extraction -Extraction using ethanol or AlCl3
- Extraction under acid conditions, precipitation of pectin from liquid phase of
pressing
Shalini et al (2010)
Cattle Feed 39% apple pomace with conventional feeds Bae et al.
Enzymes -Polygalacturonases from A. niger
-Pectolytic enzyme complex by A. niger
-β-fructofuanosidase by three A. niger species
-Xylanases using Trichoderma harzianum
-Lignocellulolytic actvity of Candida utilis
Vendruscolo et al.
(2010)
Aroma compounds Medium containing apple pomace produced a strong fruity aroma after 21 hr of
cultivation of Ceratocystis fimbriata
Bramorski et al.
(1998)
Ethanol Solid state fermentation of apple pomace was carried out for 96 h at 30˚C . Sugar
conc. reduced from 10.2% to less than 0.4% & final conc. of ethanol was more than
4.3%; fermentation efficiency of 89%
Hang et al. (1981)
Organic Acids Citric acid production using apple pomace from A. niger in SSF. Operating conditions:
Low aeration rate ( 0.8L/min), a high bed height (10cm), a large particle size ( 1.70-
2.36 mm) & elevated moisture content (78%)
Shojaosadati and
Babeipour (2002)

19. UTILISATION OF APPLE POMACE
UTILISATION DETAILS REFERENCE
Heteropolysaccharide
s
Production of xanthan through SSF of apple pomace based substrates with spent
malt grains, which acted as inert support to ↑medium porosity. Highest yield at
pomace to inert support ratio of 2:3
Stredansky and Conti
(1999)
Biopolymers Production of fungal chitosan in SSF using the watery extract of apple pomace &
the pressed apple pomace as the substrate using fungus G.butleri, yielding
0.1783g/g of apple pomace
Streit et al. (2004)
Edible mushrooms Cultivation of shiitake & oyster mushrooms showed better yield when cultivated on
apple pomace as compared to sawdust
Worrall and Yang
(1992)
Baker’s yeast Apple pomace as the carbon source in an aerobic-fed batch culture for the
production of baker’s yeast. Biomass yield of 0.48g/g of sugar was obtained but the
dough raising capacity of the baker’s yeast thus produced was same as that of
commercial yeast
Bhushan and joshi
(2006)
Pigments Apple pomace based medium was used to examine the effect of carbon and
nitrogen sources on carotenoid production by Micrococcus species. 20g/L of apple
pomace in the basic medium gave the best results/ growth
Attri and Joshi (2005)

20. CITRUS FRUIT WASTE MANAGEMENT
• About 50% of the weight of citrus fruits is discarded as waste peel, membrane, juice vesicles and seeds when
these fruits are processed (Crandall et al., 1983).
• Obtaining by-products from these wastes may increase the economic yield of the citrus juice industries. Citrus
by-products are commonly used to fortify animal fodders, but citrus peels are also used to obtain citroflavonoids,
aromatic components, carotenoids and dietary fiber concentrates.
CLOUDING AGENTS
• Citrus wastes may be used as a source of Clouding Agents (CA) for citrus beverages.
• The CA may be obtained from citrus wastes by the addition of salt after extracting the proteins. The CA also can
be obtained with the addition of alcohol or by fermentation with bakers and brewers yeast.
• These extraction processes reduced the soluble solids by almost 50% and 72% for the fermentation and alcohol
extraction, respectively. Moreover, the alcohol extraction removed all the natural color of the orange peels.

21. CFW COMPOSITION
• The citrus fruits by-product industry utilizes the residual peels, membranes, seeds and other
compounds (Braddock, 1995).
• Residues of citrus juice production are a source of dried pulp and molasses, fiber-pectin, cold-
pressed oils, essences, d-limonene, juice pulps and pulp wash, ethanol, seed oil, pectin, limonoids
and flavonoids (Ozaki et al., 2000; Siliha et al., 2000).
• The main flavonoids found in citrus species are hesperidin, narirutin, naringin and eriocitrin (Mouly et
al., 1994).
• Peel and other solid residues of lemon waste mainly contained hesperidin and eriocitrin, while the
latter was predominant in liquid residues (Coll et al., 1998).
• Citrus seeds and peels were found to possess high antioxidant activity (Bocco et al., 1998).

22. AIZES MODEL ON
CITRUS BEVERAGE
PRODUCTION
(Ngoc et al 2009)
(Medium-scale citrus processing
in Ho Chi Minh city, Vietnam)

23. CFW UTILIZATION
FIBER EXTRACTION
• The main technological steps involved in the preparation of dietary
fibers are:
• Wet milling Hammer mills with a variety of screen sizes are
preferred to colloidal mills in order to obtain a good control of particle
size.
• Washing Selective removal of the undesirable compounds and the
removal of potentially pathogenic microorganisms are the main
objectives of this operation.
• Drying Drying is the main and most expensive step in dietary fiber
production. It improves the fiber shelf-life without the addition of any
chemical preservative and reduces both the size of package and the
transport costs. Different drying methods are used in the food
industry: tunnel belt, rotatory kiln, drum dryer, etc.
• Dry milling Milling done to improve acceptability of fibers in the final
food products.

24. CITRUS FRUIT WASTE UTILIZATION:
CITRIC ACID SUBSTRATES
• Waste Aspergillus niger mycelia from a citric acid production plant were used as a
source of chitosan.
• The extraction of chitosan was operated with lysozyme, snailase, neutral protease
and novel chitin deacetylase from Scopulariopsis brevicaulis at the optimum
condition of every enzyme.
• Chitosan is soluble in acid solutions and has a wide range of uses in the cosmetic,
pharmaceutical, agricultural and food industries. In the food industry it can be used
for clarification of juices.

25. CITRUS FRUIT WASTE UTILIZATION:
DYE REMOVAL
• Activated carbon is the most employed adsorbent for dye removal from aqueous solution because of
its excellent adsorption properties. However, it is very expensive to use limiting its large-scale
application in wastewater treatment.
• Yellow passion fruit and mandarins, are cultivated on a large scale in Brazil and are of agronomic
importance because they are used in the juice industry.
• As the yellow passion fruit (PFP) and mandarin (MP) peels are very abundant in Brazil, there is a
need to find a use for these by-products of industrial activities.
• Hence, PFP and MP wastes can be used as a biosorbent for successful removal of methylene blue
from aqueous samples.

26. Thank
you