MEMBRANE FILTRATION/PROCESSING

APPLICATION IN DAIRY INDUSTRY

Group number: 04

Content

• Introduction• Main 4 technologies • Membrane characteristics• Membrane separation parameters• Principle of plant design• Application in dairy industry • Future trend• Fouling

INTRODUCTION

• The current milk industry has come about through generations of cultural and technological developments, involving many aspects from milk production to processing to retail before reaching the consumers.

• Recently the highest level of quality and safety are expected from milk products, and the market for value-added milk is ever-increasing

• Membrane separation technology is a prominent figure in ensuring that milk reach those requirements.

• The main force of membrane technology is the fact that it works without the addition of chemicals, with a relatively low energy use.

• The technology can be applied to several production methods, including milk-solids separations in the dairy industry, juice clarification and concentration, concentration of whey protein, sugar and water purification, and waste management

HISTORY OF MEMBRANE FILTRATION

• Membrane technology began in the 1920s as a form of water treatment with microfiltration

• And only began to advance significantly in the past 30 years since the development of ultra-filtration in the 1970s for the dairy industry.

• The study on RO was started in 1965

• NF membrane technology was firstly studied around 1989

DEFINITION • Membrane filtration is a technique that uses a physical

barrier, a porous membrane or filter, to separate particles in a fluid. Particles are separated on the basis of their size and shape with the use of pressure and specially designed membranes with different pore sizes

• Although there are different membrane filtration methods (RO, NF, UF and MF, in order of increasing pore size), all aim to sep.arate or concentrate substances in a liquid.

Classification by Type of Driving Force

• Pressure-driven processes Microfiltration Ultra filtration Nano filtration Reverse Osmosis

Concentration driven processes Dialysis (liquid /liquid) Pervaporation (liquid /gas) Gas separation (gas /gas) Selective separations with liquid membrane

• Thermally driven processes Membrane distillation Thermo-osmosis (thermal diffusion)

Electrically driven processes Electrodialysis

References : Anisa, M., Harleen, K., Anju, B., Raj, K., Sumaira K., and Shahnawaz, K., .2013 Commercial Utilization of Membranes in Food Industry, International Journal of Food Nutrition and Safety, 2013, 3(3): 147-170

Pressure-driven processes Microfiltration (MF)

Microfiltration is a low pressure-driven membrane filtration process, which is based on a membrane with an open structure allowing dissolved components to pass while most non-dissolved components are rejected by the membrane.

In the dairy industry, microfiltration is widely used for bacteria reduction and fat removal in milk and whey as well as for protein and casein standardisation.

Ultrafiltration (UF) Ultrafiltration is a medium pressure-driven membrane filtration process.

Ultrafiltration is based on a membrane with a medium-open structure allowing most dissolved components and some non-dissolved components to pass, while larger components are rejected by the membrane.

In the dairy industry, ultrafiltration is used for a wide range of applications such as protein standardisation of cheese milk, powders, fresh cheese production, protein concentration and lactose reduction of milk.

Nanofiltration (NF)Nanofiltration is a medium to high pressure-driven membrane filtration process.

Generally speaking, nanofiltration is another type of reverse osmosis where the membrane has a slightly more open structure allowing predominantly monovalent ions to pass through the membrane. Divalent ions are - to a large extent - rejected by the membrane.

In the dairy industry, nanofiltration is mainly used for special applications such as partial demineralisation of whey, lactose-free milk or volume reduction of whey.

• Reverse Osmosis (RO)Reverse Osmosis is a high pressure-driven membrane filtration process which is

based on a very dense membrane. In principle, only water passes through the membrane layer.

In the dairy industry, reverse osmosis is normally used for concentration or volume reduction of milk and whey, milk solids recovery and water reclamation. ( http://www.gea.com/en/binaries/Membrane%20Filtration%20in%20the%20Dairy%20Industry_tcm11-18227.pdf.)

Membrane Characteristics And Membrane Modules

• Pore size:• In Microfilteration membrane - 0.1 – 5 um• In Ultrafiltration membrane- 0.1um to 0.01um• In Nanofiltration membrane - 0.001-0.01um • In Reverse Osmosis membrane - 0.0001 – 0.001 um

• Thickness• Temperature resistant lower than 40°C 70–80°C

• Pressure resistant

Designs

• Plate and frame• Tubuler-Ceramic• Spiral-wound

Plate and frame design

• These systems consist of membranes sandwitched between membrane support plates, which are arranged in stacks , similar to ordinary plate heat exchangers. The feed material forced through very narrow channels that may be configured for parallel flow or as a combination of parallel and serial channels.

Tubular Design- Ceramic

• A tubular concept with ceramic membranes is steadily gaining in the dairy industry, especially in systems for the reduction of bacteria in milk, whey, WPC and brine.

• The thin walls of the channels are made of fine-grained ceramic and constitute the membrane. The support material is coarse-grained ceramic.

SPIRAL-WOUND DESIGN

•As the spiral-wound design differs from the other membrane filtration designs used in the dairy industry, it calls for a somewhat more detailed explanation.

• A spiral-wound element contains one or more membrane envelopes, each of which contains two layers of membrane separated by a porous permeate conductive material. This material, called the permeate channel spacer, allows the permeate passing through the membrane to flow freely. The two layers of membrane with the permeate channel spacer between them are sealed with adhesive at two edges and one end to form the membrane envelope. The open end of the envelope is connected and sealed to a perforated permeate-collecting tube

SPIRAL-WOUND DESIGN

Membrane Separation Parameters

Membranes are categorized by their,• Molecular weight cut-off (NF and UF) • Nominal pore size (MF)• Salt retention (RO and NF)

Membrane filtration is not purely based on these things its also based on, Membrane filter - thin and of fairly controlled pore size. polymers ,ceramics and rarely cellulose acetate as filter materials. Convensional filter- Flow of feed is perpendicular to the filter medium Filtration can be conducted in thick open systems. Gravity is the main force. Filter material as paper.

Separation Characteristic determine by many different factors related to membrane materials,

• Membrane manufacturing• Shape & flexibility of molecules• Flow dynamic• Transport mechanisms at the membrane surface• Narrow or wide of the membrane

• Traditional or conventional filtration is typically used for the separation of suspended particles larger than 10 µm,

• while membrane filtration separates substances with molecular sizes less than 10 µm.

• Membranes with a narrow pore size-let lower molecular weight permeate,

• membranes with a wide pore size -let material with a higher molecular weight permeate

although the two membranes are defined as having the same molecular weight cut-off.

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Principals of Plant Design

Membrane filtration plants mostly depends on, the pressure generated by the pumps

used. • The capacity of the pump(s) • The pump(s) should be insensitive to changes

in the viscosity of the processed• The pump(s) satisfy the sanitary standards

for dairy equipment.

1. Product tank2. Feed pump3. Circulation pump4. Strainer5. Membrane module6. Cooler

Membrane separation plants can be used

Batch membrane filtration

1.Membrane2.Cooler3.Strainer

Continuous membrane filtration

APPLICATIONS IN DAIRY INDUSTRY.

• Application of membranes in extending shelf life of milk• Application of membranes in whey processing• Application of membranes in Cheese industry• Application of membranes in milk protein processing• Application of membranes in milk fat processing• Role of membranes in desalting or demineralization

Separation and fractionation of milk fat globules

• MF to separate fat globules from whole milk instead of using a cream separator (Glimenius et al., 1979; Merin and Daufin, 1990).

• No industrial application of MF for this purpose yet.• Should consider about the mechanical impact and oxidation

due to high concentration of phospholipids

Membrane separations for removal of microorganisms

• An efficient alternative to heat treatment for removal of bacteria from liquid food.

• This technique is referred as cold pasteurization.• Bactocatch process-employs a MF membrane of 1.4 μm . First,

cream is separated from milk using a cream separator. This is needed to increase the VCR while maintaining high permeate flux during the MF (Rosenberg, 1995).

• Shelf life is beyond 92 d when stored in 4.2 c (Elwell and Barbano, 2006)

• Can reduce bacteria to an accepted level while maintaining typical flavor and higher nutrition value of milk.

• Can remove effectively spore-forming bacteria first while the latter is aimed to destroy vegetative pathogens.

Fractionation of milk proteins for making cheeses, caseins and whey proteins and for milk protein standardization

• MF membranes with pore size 0.1-0.2 m can be used to fractionate skimmed milk into

(1) retentate fraction enriched with micellar caseins (2) sterile permeate containing native whey

proteins• Reduces total production time, increases capacity of the

plant.• MF production of cheese also allows flexible changing of the

casein/whey protein ratio or the casein/fat ratio for desired structural and sensorial properties of final products.

• Compared to classic cheese whey, the MF contains no rennet, bacteria, and starter culture, contains extremely low lipid content (i.e., < 0.01%) (Britten and Pouliot, 1996).

• The obtained powders have better oxidation stability due to a low concentration of lipids

• Has better technological properties e.g., gelling and foaming properties (Britten and Pouliot, 1996; Diaz et al., 2004).

• UF can be applied to produce milk protein isolate (Rajagopalan and Cheryan, 1991).

• Milk protein isolate finds its applications in foods that require superior functionality. Ex.confectionery and bakery products, infant foods, meat products, soups and sauces, dry seasoning blends, and cheese base for soft cheese making …

• UF can be applied for production of cottage cheese, soft cheese varieties, some hard cheeses like Cheddar and Parmesan.

• UF offers a reliable mean to standardize protein content for making of e.g., yogurt, cheese, ice cream

Treatment of whey for production of whey protein concentrate and whey protein isolate

• Major part of commercial WPC and WPI are still produced from classic cheese whey (Marcelo and Rizvi, 2009)

• Classical cheese whey products contain,natural serum components of milk, remnants such as small fat globules, fragments of fat globule membranes, rennet enzymes, starter bacteria, etc.

• These remnants need to be removed before making WPC and WPI.

Wastewater treatment

• To treat 100 m3/d of wastewater from a dairy plant a 540 m RO unit is required.

• Water recovery could reach 95%. Vourch et al. (2008) estimated

• Purified water complying with drinking water criteria could be achieved by a two-stage RO + RO process treatment.(Vourch et al., 2005; Balannec et al., 2005; Chmiel et al., 2000; Frappart et al., 2008).

Conclusions

• Alternatives to conventional processing method.• More economic production and better quality products in terms of

both technological functionalities and nutrition value.• Applications of membrane techniques can create products,

ingredients with favorable characteristics that conventional techniques are unable to offer.

• Considered green technology due to their higher efficiency in energy usage and the winging away from using chemicals and additives

• Create the possibilities to recover valuable components in diluted effluents, by-products, and wastewater. These applications bring more benefits to the producers

• A very good technology for wastewater treatment.

Future Trends• Membrane technology have the potential to contribute and

help manufacturers produce even higher-quality products at reasonable costs.

• Can apply ‘reduce, reuse, recycle’ methodology to reduce volumes of water used per production unit and will look for external support to achieve these best practices.

• Reuse of process waste water will provide opportunities for very significant water efficiency and security improvement.

• Recycle is the process of converting waste materials into materials and objects

• Medicinal usage as a pharmaceutical drugs.• Waste water treatment.• Crude oil extraction.• Food and beverage industry.

Membrane Technology in Wine and Beer Industry.Membrane Technology in Juice Industry

Fouling• Fouling is the accumulation of unwanted material on solid

surfaces to the detriment of function.• Fouling causes a decline in performance of membrane

processes, in which flux is very high initially but then decline drastically as materials of foulant accumulate on membrane surface.

• The types and amounts of fouling are dependent on many different factors, such as feed water quality, membrane type, membrane materials and process design and control.

Fouling

• Methods to control fouling have increased the complexity in equipments and operation.

• Therefore, we need innovative techniques for the development of cheap, easily available, superior and long lasting membranes.

• Extended shelf life and the demands of both can be fulfilled by the use of the membrane technology.

• Fouling can be maintain by, - regular cleaning , -use of low fouling membranes - membrane modules with suitable channel heights -applying high pressure - application of electric potential -ultrasound waves, -microturbulence, - ceramic membranes, - uniform transmembrane pressure (UTP), -vibrating and rotating disc modules, -use of turbulent flow of liquids

References

• JOURNAL OF FOOD RESEARCH AND TECHNOLOGY Journal homepage: www.jakraya.com/journa/jfrt

• Membrane separations in dairy processingThien Trung Le1, Angeli D. Cabaltica2 and Van Mien Bui11Faculty of Food Science and Technology, Nong Lam University – Ho Chi Minh

City, Linh Trung Ward, Thu Duc District, Ho Chi Minh City, Vietnam 2Department of Civil Engineering, International University, Ho Chi Minh City National University, Ho Chi Minh City, Vietnam

• www.dairyprocessinghandbook.com/chapter/membrane-technology