State of the art in processing wastewater from food & beverage industry: challenges, hot topics and emerging technologies.

Tecnologie Innovative per il Controllo Ambientale e lo Sviluppo Sostenibile scrl
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TICASS
Tecnologie Innovative per
il Controllo Ambientale e
lo Sviluppo Sostenibile scrl
Imperia, October 2, 2018
«State of the art in processing wastewater from food & beverage
industry:
challenges, hot topics and emerging technologies.»
Claudia Cattaneo – c.cattaneo@ticass.it
Soggetto Gestore
Polo Regionale Ligure di Ricerca e
Innovazione «Energia, Ambiente,
Sviluppo Sostenibile»
Managing Body
Regional Research and Innovation
Hub «Energy, Environment,
Sustainable Development»

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Wastewater Treatment in the Food&Beverage Industry
Food industry needs large amounts of water for various processes and it is one of the
most resource demanding branches of industry.
FoodDrink Europe, Environmental Sustainability Vision towards 2030

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EEA, 2004, Managing Environmental Sustainability

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Water classification categories
used in the food and beverage industries
 General purpose
 Cooling
Process
Boiler feed
wastewater

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General Purpose Water
General purpose water includes all of the water used in washing and sanitizing
raw materials, processing equipment, plant facility and ancillary equipment
 large amounts
 it should be drinkable, clear, colorless and free of contaminants (no taste no
odour).
 In-plant chlorination usually is the only treatment required, with the main
advantage to promote microbe reduction….
….BUT… risk of formation of chloroderivates in water

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Process Water
Water used for cooking or added directly to the product. It must be:
 drinkable
 of sufficient quality so as not to degrade product quality. This includes being
free of dissolved minerals that make water excessively hard or affect taste.
Most of the product in beverage production consists of process water, so
treatment to achieve taste objectives is especially important. Often, treatment
beyond that required to meet safe drinking water standards is essential for
consistent quality.
Treatment processes used in bottled water often include:
 softening, reverse osmosis and deionization, to reduce hardness (can affect
the texture of the raw materials to be processed; such as certain vegetables.
Iron, manganese or sulfate can have an undesirable affect on the taste of the
product.
 chemical, thermal, radiation, and ultrasonic treatment or cell disruption.

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Cooling Water
Cooling water not in contact with food products or sealed containers does not
have to be potable or meet the requirements of process water, as the removal
of staining minerals and odors is not as important.
However, preventing the accumulation of scale in pipe and equipment is
important, especially when cooling water is recycled.
The most efficient processing systems include recycling circuits to reduce
cooling water waste, thus reducing processing costs. Potable water, even from
public supplies, often has to receive additional treatment such as softening to
avoid scale and deposits to be suitable for cooling.

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Boiler Feedwater
Boiler feedwater requires the removal of hardness. This may be the only
treatment process applied to the water; if this water is not in contact with
food, it does not have to be potable.
Boiler feedwater for high-pressure boilers requires:
 demineralization or the removal of all dissolved solids. Almost all potable
water must have minerals removed through additional treatment to be
suitable for boiler feed.
 Reduction in microorganisms (producing color and odor in water and
possible vehicle for contamination of the equipment and finished product).
If pathogenic bacteria is introduced in the contamination, food poisoning
could occur.

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Wastewater
They proportionally derive from previous water streams.
Food wastewater contains residues that deplete the oxygen in receiving
streams.
Chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) are
common measurements used to determine water quality and they are usually
used to indicate lost product and wasteful practices. High BOD5 and COD
levels indicate increased amounts of product lost to the waste stream.
At any point in a particular food processing operation, the relationship
between BOD5 and COD is fairly consistent. However, the ratios of these two
measures vary widely depending on the type of product.

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Preventive actions
In light of the anticipated increase in demand for water worldwide,
significant efforts have been made to work with food chain partners to
improve water management as well as waste water quality and water
recovery and re-use:
 Food operators initiatives to address water use throughout the entire
life-cycle of a product, in addition to water disclosure and voluntary
water stewardship.
 Reduction of water use on-site on a voluntary basis employing tools to
measure water use, adopting water management practices and investing
in water-efficient technology.
BUT….

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Water saving cannot be separated from the energy approach
Environmental objectives must be economically viable
Process design for each food industry application should be
specific to your plant needs. When the main concern is to reduce
regulated constituents to permissible discharge levels a pre-
treatment system is often the most direct and cost-effective
solution.
CHALLENGES

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Main technologies for wastewater treatment
in agrofood industry
Chemical –physical treatments (i.e. DAF technology, flocculation, coagulation,
settling)
Phytodepuration including filtration on zeolitic support
Integrated Membrane processes (physical filtration, biological processes with
activated sludge and attached biomass processes)

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 Absolute barrier against unwanted
substances
 Separations at molecular level
 They enable the achievement of
water destined for human
consumption starting from any kind
of raw water
 They enable the achievement of high
quality water
Membrane processes seem to be the ideal system for the solution of
problems yet unsolved….

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Membrane technology in agrofood industry
Food product has a complex composition
H2O, main components, minor components
Separation processes play a fundamental role
 Water removal
 Greases separation
 Proteins separation
Minor components removal
Microorganisms removal
MEMBRANE PROCESSES
 They do not modify components
in natural products
 They act at low temperature
 Mainly physical separation
 No introduction of new products

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• Separation
– High capacity to selectively and efficiently separate without product
modification or loss; They do not modify the chemical nature of
substances in final products; no new substances
• Energy
– Energy saving: no heat is needed (except for membrane distillation)
• Flexibility
– In terms of concentration range and inlet flow variability
They could be easily integrated in the food processing chain in order to
obtain product valorisation and reduced wastewater generation (new
effluents could be properly discharged in receiving water bodies)
Membrane systems : general advantages

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Membrane Processes used in food and
beverages industry
Fruit juices and syrups
production
Dairy industry
Brewing
Wine and vinegar
production
Proteins production:
from eggs, from
potatoes
Sugar industry
Vegetable oils
Biological processes
Starches and
derivates industry
Gelatine industry

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Membrane limits
• High investment costs for big size systems
• Membrane durability
• Maintenance and management
Other costs
4%
Initial
investiments
38%
Membrane replacement
27%
Energy costs
16%
Cleaning solutions
5%
Manpower
10%
Costs ripartition % dei costi

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Membrane and separation
• The membrane is a physical barrier which allows the selective passage of
specific cmponents of a mix (solutes or solvent)
• In comparison to traditional filtration the mix solution flows in parallel to
the membrane and not perpendicularly.
Separation process driving forces
•Concentration difference (D)
•Pressure difference (MF, UF, NF, RO, PV)
• Electrical potential difference (ED)
•Vapour pressure difference (MD)
Compact selctive layer (1 µm)
Macroporous layer (100 µm)

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The feeding flows in aparallel to the
membrane and it generates two
streams:
• Concentrate
• Permeate
s2
s1
Permeate
Concentrate
Feeding
Membrane
Parameters in Membrane processes
Permeate flow [L m-2 h-1]
Dipending on P, T, u, µ
Retention
Membrane processes
FPM
t
RRR
ΔπP
J



100
C
CC
R%
f
pf




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MEMBRANE SEPARATIONS
RETENTION CHARACTERISTICS
Suspended
MICROFILTRATION particles
Macromolecules
ULTRAFILTRATION
Sugar
NANOFILTRATION Divalent salts
Dissociated acids
REVERSE OSMOSIS Monovalent salts
Undissociated acids
Water
Microfiltration (MF)
Colloids, microorganisms, pectines, suspended
solids separation
Very low pressure values (<2 bar)
Ultrafiltration (UF)
Macromolecules with different molecular mass
separation
Low pressure values (<10 bar)
Nanofiltration (NF)
Sugars, salts and solution purification
Pressure value lower than RO
Reverse Osmosis (RO)
Salts concentration
High pressure value (up to 100 bar)
Application and membrane process characteristics

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Feeding
Volume
Physical properties
- viscosity
- Temperature
- Suspended solids
- Bacterial load
Chemical properties
- analysis
- pH
- Dissolved solids
- Chemical compatibility
Concentrate
- ‘Product’?
-‘effluent’?
- ‘Specific requirements’?
Permeate
- ‘Product’? Pure fluid?
- Recycle stream?
- ‘Effluent to be discharged’?
- Specific requirements?
Operational constraints
Process Temperature
Residence Time
Cleaning solution
Definition of a valuable membrane process
Depending on feeding
characteristics

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Factors influencing the process feasibility
• Preliminar information obtained with the pilot plant
• Membrane selection: the most proper for the considered application (Flow, Selectivity)
•Products quality: evaluation of different possibile results according to studied processes
• Definition of operative conditions (Pressure, Concentration, Temperature, Recycle flow
rate, Fouling control)
The process application requires
the definition of
•Configuration
•Pretreatment
• Feeding composition
• Final destination for obtained streams
(Concentrate, Permeate)
•Fouling
• Costs/benefit analysis

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Tomato juice production
Advantages
•Higher product quality (lycopene, colour, vitamine C, ecc.)
•New products development
• Higher quality in wastewater
Concentrate juice 7-8 Bx
effluent
Tomato
juice
RO
Reformulation
MF serum
Succo di pomodoro
concentrato
Tomato juice
MF
Wastewater
RO
Concentrated
pulp
Concentrated
Integrated process

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Membrane system with high recovery factor
Concentrate
(high Brix i.e. 40-42 Bx
orange juice)Feeding
MF
Permeate
RO
Low P
RO
High P
RO
Permeate
(recycle or effluent)
Concentrate MF
(High concnetration achievement)

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Membrane Biological Reactor (MBR)
Combines biological processes and microfiltration or ultrafiltration processes
• MBR for the solid/liquid separation
• MBR for the gas transport in a liquid without bubble formation
• MBR for the organic compounds extraction from liquids in aggressive water
and/or high salt content
Nowadays, only full scale MBR process applied to the solid/liquid separation
have been realised.

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 The membrane
replaces
secondary
settling
 The biomass
concentration
is higher than
traditional
activeted
sludge plants
(u to 20-25 g/l)
Comparison between membrane and conventional technology

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Disinfection
Competitive Processes:
Oxidation(chlorine, ozone)
Ultraviolet
Advantages Weak Points
Membranes Absolute barrier Life time?
Lack of long term feedback
Oxidation Well - known By--products
Resistance of certain pathogens
U.V. Compactness, costs Lack of long term feedback
Efficiency to be demonstrated

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Conclusions
Membrane processes allow to:
• Develop integrated technologies to improve product quality
• Develop new products
• Recover of high added value products
• Solve/reduce environmental issues

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Olives
Washing
Olive paste
Pressing
KneadingCrushing
Oil
Vegetation waters
Membrane processes
residue
Olive oil production cycle
(OMW)

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OMW
Olive washing water
Vegetation water
Added centrifugation water
Filter disc washing water
Instrumentation washing water
Elements Amount (%)
83,2
1,8
Water
Inorganic elements
Organic elements
1,0
2,0
7,5
1,5
1,5
1,5
Lipids
Nitrogenous compounds
Sugars
Inorganic acids
Polyalcohol
Pentoses, Tannins
Glycosides traces
5,5
15.000 – 110.000 (mg/l)
pH
BOD
5
COD 20.000 – 150.000 (mg/l)
Surface waters Public sewage
CODMax 40 500
BOD5 Max 160 250
Legal restrictions for industrial
discharges (d.lgs.11 maggio 1999, n°152)
Olive Mill Wastewater (OMW)
belongs to the category of agro-industrial waste and is one of the most difficult wastewater flows to manage.
OMW is generated during the olive oil production in large volumes, and is characterized by high polluting load due
to the large amounts of organic constituents:

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Integrated MF/RO process for OMW treatment
OBJECTIVES:
MF/RO technology is studied in order to evaluate its performance in OMW
treatment application.
Quality of the product and by-products, their volumes, treatment capacity will
be defined.

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INTEGRATED MF/RO PROCESS SCHEME
To separate pressure driven membrane processes integrated in one technology for
OMW treatment:
Pre-treatment: 5 µm net filters
1st step: MF process
Two outlet streams:
 lower volume MF concentrate
(by-product for valorization)
 a main stream - MF permeate
(partially depurated OMW for
further treatment in RO process)
2nd step: RO process
Two outlet streams:
 low volume RO concentrate (polyphenols
rich by-product for valorization)
 a main stream - RO permeate (depurated
water for irrigation/reuse)

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MF
Obtained results for integrated MF/RO process
65L
MF Concentrate
COD 177g/L
935L
MF Permeate
COD 20g/L
Cond. 5,1mS/cm
RO
1000L
COD 30g/L
45L
RO Concentrate
COD 158g/L
890L
RO Permeate
VCR ~15
COD red.: 30%
VCR ~21

State of the art in processing wastewater from food & beverage industry: challenges, hot topics and emerging technologies.

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