Internship Report (Amr Dairy)

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Training Report
On
Summer Internship At Amr Dairy, Amreli.
Subject: Summer Internship (370001)
Academic Year: - 2021-22, 7th semester
Prepared by
180110105018 – HADIYA DHRUYEN
Dr. Haresh K Dave
Placement Faculty
Coordinator
Department of Chemical Engineering
G H Patel College of Engineering and Technology
Vallabh Vidyanagar, Anand-388120
Gujarat Technological University,
Chandkheda, Ahmedabad.
Dr. Mathur Kumar Bhakhar
Internal Guide

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ACKNOWLEDGEMENT
I am very thankful to AMR DAIRY for giving me the opportunity to
undertake my summer training at their prestigious AMRELI DISTRICT
CO-OPERATIVE MILK PRODUCER A UNION LTD. It was a very
good learning experience for me to have worked at this site.
I would like to convey my heartiest thanks to Mr. D. R. Ramani, General
Manager, I would also like to give my heart-felt thanks to Mr. Brijesh
Kanani, who heartily welcomed me for the internship, guided and
encouraged me all through the summer training and imparted in-depth
knowledge of the programme. I would like to thank all the department
heads of Amr Dairy, for giving their precious time and valuable guidance
during my internship programme.
I am extremely thankful to Dr. Kaushik Nath , Head of department,
Chemical Engineering and Dr. Haresh K Dave Placement Faculty
Coordinator, G H Patel College of Engineering and Technology, Vallabh
Vidyanagar for providing me facilities to work in, without which this
work would not have been possible.
Last but not the least; I would like to thank all the staff of AMRELI
DISTRICT CO-OPERATIVE MILK PRODUCER A UNION LTD
family, for being so helpful during this summer training.

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PREFACE
Every student of Bachelor of Technology in Chemical Engineering, has
an essential requirement to do 15 days of internship in any of the well
reputed organization. The purpose of this program is to acquaint the
students with practical applications of theoretical concepts taught to them
during conduct of their course.
Engineering is not only the bookish knowledge of a scientific field and
job but also provides many opportunities of getting actual practical
experience and Internship is one of them.
I have completed my internship in Amr Dairy, Amreli . During my
internship I had been rotated different departments as storage, production,
utility, ETP, CIP, packing, transportation etc in two weeks, this
movement and working provide a complete knowledge of Dairy
production. Really, it was a nice opportunity to have a close comparison
of theoretical concept in practical field. This report may depict
deficiencies on my part but still it is an output of a student’s efforts, for
which I beg pardon.
The output of my analysis is summarized in a shape of Internship the
contents of the report Shows the detail of sequence of these.

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NOC FOR INTERNSHIP

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DECLARATION
It is hereby declared that the Summer Internship Report entitled “Summer
Internship At Amr Dairy, Amreli” has been prepared as the part for the
completion of subject “Summer Internship (370001)” administration from
Department of Chemical Engineering, G H Patel College of Engineering
and Technology and it is based on the original research work and will be
used only for the academic purpose. It will not be produced in any
condition as a source of information to an industry.
STUDENT NAME :-
SIGNATURE :-
COMPANY GUIDE :-
SIGNATURE :-
Hadiya Dhruyen Bhupatbhai
Mr. Brijesh Kanani
SIGNATURE :-
Internal Guide :- Dr. Mathur Kumar Bhakhar

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CONTENT
ACKNOWLEDGEMENT 2
PREFACE 3
CERTIFICATE 4
NOC FOR INTERNSHIP 5
DECLARATION 6
COMPANY PROFILE 8
OVERVIEW OF DAIRY PROCESSING 15
16
18
UTILITY SECTION 20
WATER TREATMENT PLANT 21
BOILER 22
REFRIGERATION PLANT 23
AIR COMPRESSOR PLANT 26
EQUIPMENT & AUXILIARIES USED INDAIRY INDUSTRY 27
PIPING 28
VALVES 30
PUMPS 33
HOMOGENIZER 38
HEAT EXCHANGER 41
CONVEYOR 45
CLEAN IN PLANT (CIP) 49
EFFLUENT TREATMENT PLANT (ETP) 54
CASE STUDY 58
REFRENCES 63
MILK PROCESSING
BUTTER PROCESSING

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INTRODUCTION
As the name suggests, Amreli District Co-operative Milk Producer a Union Ltd. (AMR
Dairy) is a co-operative organization. This organization was formed in the year 2002
and started function 2007 with the assistance of Gujarat government, The AMR Dairy
gets registration under GCMMF in 2008 to expand its progress in Dairy Industry in all
directions.
The main objective of establishing this organization was of economic and social welfare
by providing remunerative returns to the farmers and by providing quality products
which are good value for money to consumers.
At present, it has become an apex milk producer in the Saurashtra region and especially
in Amreli district. The organization is affiliated to Gujarat Co-operative Milk
Marketing Federation (GCMMF) which is the largest food products marketing
organization of India.
Name of the organization Amreli District Co-operative Milk
Producer a Union Ltd.
Address AMR Tribheto, Dhari Road,
Amreli- 365601
Establishment year 2002
Form of organization Co-operative
Founder chairman Mr. Dilipbhai Sanghani
Chairman Mr. Arvindbhai N. Sanghani
Vice chairman Mr. Mukeshbhai N. Sanghani
Founder Director Mr. Parsotambahi Rupala
Managing Director Dr. R. S. Patel
Plant capacity 4.5 LLPD
Area 4850 sq. meter
Products Market milk, Butter milk, Dahi, Ghee.
Bankers Amreli District Co-operative Bank Ltd.
Accounting year April to March

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THE TIME LINE OF AMR DAIRY:
 Amreli District Co-operative Milk Producer's Union Ltd. (AMR Dairy) is
established in the year 2002.
 It affiliated to GCMMF, the largest milk marketing federation in India in the
year of 2008.
 In 2012, set up of new dairy milk processing. Start production in the year 2016.
 Certification from FSSAL ✓ Certification from ISO & AGMARK.
 At present, it has become an apex milk producer in the Saurashtra region and
especially in Amreli district.
 It also established an animal feeding industry "AMR cattle feeding factory in
the year 2016.
 In the year 2019 increase the capacity of plant from 2 LLPD to 4.5 LLPD.
PLANT DESCRIPTION:
AMR dairy has a high-tech milk producing plant located at Amr Tribheto, Dhari road,
Amreli. The Plant designed by the TETRAPAK India Pvt Ltd, over an area of 4850 Sq.
m. and processes more than 2 lakhs litres of milk every day. The plant is fully
automated with the entire automation engineering having been executed by TETRA
PAK India Pvt Ltd, PUNE. Run by highly professionals and technocrats. The plant
strictly works on the guidelines laid down by the GMP and HACCP programs.
The advanced facility of AMR dairy at Amreli in the state of Gujarat, India has a large
production capacity. Spread across 3850 sq. m., the plant has a capacity of processing
6 LLPD in future, presently it processes 2 to 2.6 LLPD.
BACKWARD INTEGRATION:
The backward integration program of AMR dairy is the result of its commitment to
produce dairy products per international standards. To achieve this aim, the Company
has set up more than 18 BMC for village level society of Amreli, Junagadh and Gir
Somnath district to preserve the quality of milk.

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Demonstration cattle feed making industry "AMR DAN" and training center also been
setup to educate the rural milk producers to improve and upgrade their native skills
regarding genetic improvement of the milch-cattle, disease control and regulated
feeding
OBJECTIVE AND BUISNESS PHILOSOPHY:
AMR dairy are committed to continuously strive to manufacture and Supply good
quality and safe milk & milk products
To
 Eliminate the risk of consumer health.
 Satisfy the needs and expectations of interested parties.
 Uplifts the socio-economic status of member producers and employees
By
 Comply with all applicable statutory, regulatory, customer, social, neighbour
and interested parties requirements.
 Continual Improvement in processes for clean production, pollution prevention
and optimize resource utilization in all operations.
 Use of good qualityof raw and packing material, services, process it in hygienic
condition by following quality and food safety management system.
 Appropriate to the purpose and context of the organization’s and supporting its
strategic direction through organizations specified objectives within time frame.
 Adopting latest technology, effective communication at all level, providing
latest training to employee and reviewing this policy regularly.
To be a global leader in the field of dairy industry

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FOOD SAFETY CERTIFICATION & POLICY OF AMR DAIRY
Amreli District Co-operative Milk Producer's Union Ltd (AMR Dairy) follows food
safety norms given by
1) HACCP
2) ISO 22000 & 9000
3) ESSAI
4) AGMARK
5) 5S & GMP practices
The five key principles of food hygiene, according to WHO are -
1. Prevent contaminating food with pathogens spreading from people, pets,
and pests.
2. Separate raw and cooked foods to prevent contaminating the cooked foods.
3. Cook foods for the appropriate length of time and at the appropriate
temperature to kill pathogens.
4. Store food at the proper temperature.
5. Do use safe water and sale raw materials.
FSSAI
In order to consolidate the laws relating to food and to
establish the Food Safety and Standards Authority of
India for laying down science-based standards for
articles of food and to regulate their manufacture,
storage. distribution, sale and import, to ensure
availability of safe and wholesome food for human consumption and for matters
connected therewith or incidental thereto, the Govt. of India, has passed this law.

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AGMARK
1) To assure the consumers a product of pretested quality
& purity.
2) To enable the producer of good quality products to have
better returns.
3) Used mainly for ghee.
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION
(ISO)
Characteristics of IOS standards are
 Democratic
 Voluntary
 Market driven
 Globally relevant
ISO 9000- Quality management system
ISO 22000-food safety management system
HACCP (HAZARD ANALYSIS CRITICAL CONTROL POINT)
HACCP is a systematic approach to the identification, evaluation, and control of food
safety hazards based on the following seven principles:
Principle 1: Conduct a hazard analysis.
Principle 2: Determine the critical control points (CCPs).
Principle 3: Establish critical limits.
Principle 4: Establish monitoring procedures.

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Principle 5: Establish corrective actions.
Principle 6: Establish verification procedures.
Principle 7: Establish record-keeping and documentation procedures.

OVERVIEW OF DAIRY PROCESSING
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The dairy industry is divided into two main production areas: -
 the primary production of milk on farms—the keeping of cows (and other
animals such as goats, sheep etc.) for the production of milk for human
consumption.
 the processing of milk—with the objective of extending its saleable life. This
objective is typically achieved by (a) heat treatment to ensure that milk is safe
for human consumption and has an extended keeping quality, and (b) preparing
a variety of dairy products in a semi-dehydrated or dehydrated form (butter,
hard cheese and milk powders), which can be stored
The processes taking place at a typical milk plant include:
 receipt and filtration/clarification of the raw milk.
 separation of all or part of the milk fat (for standardisation of market milk,
production of cream and butter and other fat-based products, and production of
milk powders);
 pasteurisation;
 homogenisation (if required);
 deodorisation (if required);
 further product-specific processing;
 packaging and storage, including cold storage for perishable products;
 distribution of final products.
In a flow diagram (1) outlining the basic steps in the production of whole milk, semi-
skimmed milk and skimmed milk, cream, butter and buttermilk. In such plants, yogurts
and other cultured products may also be produced from whole milk and skimmed milk.
MILK PROCESSING

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The butter-making process, whether by batch or continuous methods, consists of the
following steps:
 preparation of the cream;
 destabilisation and breakdown of the fat and water emulsion;
 aggregation and concentration of the fat particles;
 formation of a stable emulsion;
 packaging and storage;
 distribution.
In a flow diagram (2) outlining the basic processing system for a butter-making plant.
The initial steps, (filtration/clarification, separation and pasteurisation of the milk) are
the same as described in the previous section. Milk destined for butter making must not
be homogenised, because the cream must remain in a separate phase. After separation,
cream to be used for butter making is heat treated and cooled under conditions that
facilitate good whipping and churning. It may then be ripened with a culture that
increases the content of diacetyl; the compound responsible for the flavour of butter.
Alternatively, culture inoculation may take place during churning. Butter which is
flavour enhanced using this process is termed lactic, ripened or cultured butter. This
process is very common in continental European countries. Although the product is
claimed to have a superior flavour, the storage life is limited. Butter made without the
addition of a culture is called sweet cream butter. Most butter made in the English-
speaking world is of this nature.
Both cultured and sweet cream butter can be produced with or without the addition of
salt. The presence of salt affects both the flavour and the keeping quality. Butter is
usually packaged in bulk quantities (25 kg) for long-term storage and then re-packed
into marketable portions (usually 250 g or 500 g, and single-serve packs of 10–15 g).
BUTTER PROCESSING

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WATER TREATMENT PLANT
Water needed in plant is provided from the water treatment plant installed in the utility
section of the company situated at the rear part of the company. In this the ground water
is pumped to the primary filter for filtration, here insoluble particle is separated, then it
is sent to base exchanger made of NaCl resin, for treating hardness of water i.e.
magnesium and calcium salt, this soft water is used for two purpose firstly for cleaning
and secondly some part of it is pumped to R.O. filter. Here there were two R.O. filter
one of 10 m3
and second 20 m3
they were operated in between 5-7 kg/cm2
pressure
according to the need of the plant. The water treatment plant treated about 3,50,000
lit/day of water. The water after treatment is pumped to the plant at about 2-3 bar
pressure.
Ground
Water
Filter
Base
exchanger
Storage R.O. filter
To
Plant/Boiler

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BOILER
The boiler used in the plant was a shell and tube type, three pass steam boiler i.e. the
combustion gas that are produced inside them in the burner go round circuit that has
three part before leaving it. The boiler was a auto operating boiler i.e. the when water
level indicator goes below 50% the feed starts circulating water on the shell side of the
boiler. There is also air pre-heater attached to the boiler where the hot flue gas heat is
utilize to pre-heat the water. The boiler is operated at about 200o
C and about 5-10
kg/cm2
pressure. The fuel used for heating purpose is a furnace fuel that comes from
Hazira, Surat. The fuel of 5 kg/ hr is injected into the boiler thorough a spray and a 1100
watt spark plug is used to ignite it. A total of 1200 kg of fuel is used to every day on a
regular load, so this may vary according to load on the process. These boiler can
produce 4 tonnes of steam per hour. These steam goes to steam header which is then
pumped to various section of plant. Here for continuous operation of plant there were
two boiler used, where each were operated simultaneously while one is prepared. The
fuel inlet temperature was 122oC.
Specification
Name SHELLMAX
Mfg. by THERMAX Limited
Type 3-PHASE SMOKE TUBE BOILER
Model SM-40DJ/10.54/57
Capacity 4 TON
Fuel FO: AIR (1:3)
Working Pressure 7 BAR
Design Pressure 10.54 BAR
Voltage / Phase / Frequency 415V / 3 PHASE / 50 Hz
Conn. Load 27.6 KW
Feed oil Temperature MIN. 12000
C

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REFRIGERATION PLANT
Refrigeration plant is fitted to provide chilled water need to cool milk, buttermilk etc.
The water from water treatment plant is store in a overhead tank from which water is
stored in cooling tanks where coolant containing pipes cools the water down and then
it is pumped to various section of pumps. The cold coolant after receiving heat is
pumped to compressor where it is compressed from 3-4 bar to 14-15 bar and
temperature is increased from -2o
C to 75o
C . The compressor used is a screw type
compressor. After compression coolant is passed to condenser. Where it is condensed
to liquid, here the coolant used is Ammonia NH4. From condenser the coolant is passed
to economizer where it is expanded to 2-3 bar pressure here the gas is partially
converted to liquid form the remaining liquid from the bottom of economizer is passed
to accumulator where it is converted to gas phase with 99% efficiency, this cycle is
repeated accordingly to the needs of process. The transport of the chilled water to
through the whole plant is done by insulated pipes. This chilled water is pumped
through out plant by a set of primary and secondary pump each contain 2-3 pumps. This
plant has cooling effect of about 180 tons.
Specification of Equipment’s in refrigeration plant
1 Screw Compressor
Company YORK INDIA LTD.
Model No. SGC1913
Serial No. PMP18/PMP17
Refrigerant AMMONIA (NH3)
Refrigeration capacity 180 TR
Compressor motor power 22 KW
Voltage / Phase / Frequency 415V / 3 / 5 Hz
Speed 4500 RPM
Manufacture in the year 2012
Design pressure 21 Kg/ cm
Design temperature 1200 C
No. of Compressor 2

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2 Condenser
Mfg. by ALFA LAVAL (INDIA) LTD.
Type PHE type water cooled condenser
Model MK15BWFGR
Sr.no. 30115-60-520/557
Manufacture in the year 2012
Design pressure 8.0 bar(water), 25 bar (ammonia)
Design temperature 500C(water), 1600C(ammonia)
No. of Condenser 2
3 Ammonia Receiver Tank (HP Receiver)
Manufactured by UMA INDUSTRIES
Sr. no. 202/203
Capacity 700 lit.
Process fluid Ammonia
Year 2013
Working pressure 18 kg/cm2
Test pressure 21 kg/cm2
No. of Receiver tank 2
4 Economizer
Mfg. by. UMA INDUSTRIES
Serial no. 200/201
Type Flash type
Year 10/13
Test pressure 21 g/cm2
No. of Economizer 1

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5 Accumulator
Mfg. by. UMA INDUSTRIES
Serial no. 10/13
Year 199
Test pressure 21 g/cm2
No. of Economizer 1
6 Evaporator
Mfg. by. ALFA LAVAL (INDIA) LTD.
Type PHE type water cooled condenser
Model MK15BWFGR
Manufacture in the Year 2012
Working pressure 15 bar
Test pressure 12 bar
No. of Economizer 1
7 Oil Cooler
Made of York
Oil used Frick oil #3
Suction Pressure = 3 bar, Temperature = -20C
Discharge Pressure = 15.6 bar, Temperature = 200C
Oil Pressure = 11.79 bar, Temperature = 38.40C
Oil differential Pressure = 0.14 bar
Oil separator Temperature = 52.80C
No. of oil Cooler 1
8 Ice Bank Tank
Capacity 30 KL + 30KL
Dimension 10m × 10m × 3m
Agitators 2(5 HP each)
pH of IBT water 7.5-8.5
Hardness Less than 300 ppm
Total dissolving solution 550-60
No. of ice bank tank 01

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AIR COMPRESSOR PLANT
Air compressor plant of the utility section provides the compressed air needed for the
pneumatic control of the plant. Here the compressor used is a positive displacement
compressor. This compressor uses principle by pumping air into an air chamber through
the use of the constant motion of piston they use one way valve to guide air into and
out of a chamber whose base consist of moving piston. The operating pressure set points
were 5-7 kg/cm2
.
Specification
Mfg. by ATLAS COPCO
Serial no. AP1788589
Type ZT18(oil free-Air)
Max. Work Pressure 7.2 bar/ 105 psi/ 0.72 mpa
UV 48.1 L /sec. / 102efu/2.98m3/mm
Work Temperature 500C
Power & speed of motor 18kw-25Hp/2940rpm
Voltage / Frequency 400v / 50 Hz

EQUIPMENT & AUXILIARIES USED IN
DAIRY INDUSTRY
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PIPING
The product flows between the components of the plant in the pipe system. A dairy
also has conduit systems for other media such as water, steam, cleaning solutions,
coolant and compressed air. A waste-water system to the drain is also necessary. All
these systems are basically built up in the same way. The difference is in the materials
used, the design of the components and the sizes of the pipes. All components in
contact with the product are made of stainless steel. Various materials are used in the
other systems, e.g. cast iron, steel, copper and aluminium. Plastic is used for water
and air lines, and ceramic for drainage and sewage pipes. The following section deals
only with the product line and its components. The pipe systems for service media are
described in the section dealing with utility installations.
The following types of fittings are included in the product pipe system:
• Straight pipes, bends, tees, reducers and unions
• Special fittings such as sight glasses, instrument bends, etc.
• Valves for stopping and directing the flow
• Valves for pressure and flow control
• Pipe supports
Figure 1: Some examples of fittings for
permanent welding.
1. Tees
2. Reducers
3. Bends
Permanent joints are welded, figure 1. Where disconnection is required, the pipe
connection is in the form of a threaded union with a male end and a retained nut with
a joint ring in between, or a clamped union with a joint ring, figure 2. The union
permits disconnection without disturbing other pipework. This type of joint is
therefore used to connect process equipment, instruments, etc. that need to be

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removed for cleaning, repair or replacement. Different countries have different union
standards. These can be SMS(Swedish Dairy Standard) also used internationally, DIN
(German), BS (British), IDF/ISO* and ISO clamps (widely used in the US). Bends,
Tees and similar fittings are available for welding, and with welded unions. In the
latter case, the fitting can be ordered with nut or male ends or with clamp fittings. All
unions must be tightened firmly to prevent liquid from leaking out or air from being
sucked into the system and causing problems in downstream parts of the process.
Figure 2: Dairy unions of different standards.

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VALVES
There are many junctions in a piping system where product normally flows from one
line to the other, but which must sometimes be closed off so that two different media
can flow through the two lines without being mixed. When the lines are isolated from
each other, any leakage must go to drain without any possibility of one medium being
mixed with the other. This is a common problem faced when engineering dairy plants.
Dairy products and cleaning solutions flow in separate lines, and have to be kept
separate. Therefore the system used here is called mix proof valve system. There are
many places in a piping system where it must be possible to stop the flow or divert it
to another line. These functions are performed by valves. Seat valves, manually or
pneumatically controlled, or butterfly valves, are used for this purpose.
.
SEAT VALVES
The valve body has a seat for the closing plug at the end of the stem. The plug is lifted
from and lowered on to the seat by the stem, which is moved by a crank or a
pneumatic actuator, figure 3. The seat valve is also available in a change-over version.
Figure 3 : Sanitary mix-proof valve systems.
1. Swing bend for manual change between
different lines.
2. Three shut-off valves can perform the same
function.
3. One shut-off valve and one change-over valve
can do the same job.
4. One mix-proof valve is enough for securing
and switching the flow.
This valve has three to five ports. When the plug is lowered the liquid flows from
inlet 2 to outlet 1, and when the plug is lifted to the upper seat, the flow is directed
through outlet 3, according to the drawings to the right in figure 4. This type of valve
can have up to five ports. The number is determined by the process requirements.
Various remote controlled actuator alternatives are available. For example, the valve
can be opened by compressed air and closed with a spring, or vice versa. It can also
be both opened and closed by compressed air Actuators for an intermediate plug
position and for two-stage opening and closing are also available. The valve control
unit, figure 5, is often fitted as a unit on the top of the valve actuator. This top unit

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usually contains indication sensors for the valve position for feedback to the main
control system. A solenoid valve is fitted in the air conduit to the valve actuator or in
the top unit. An electric signal triggers the solenoid valve and allows compressed air
to enter the actuator. The valve then opens or closes as required. On the way, the
compressed air passes through a filter to free it from oil and other foreign matter that
might affect proper operation of the valve. The air supply is cut off when the solenoid
is de-energized and the air in the product valve is then evacuated through an exhaust
port in the solenoid valve.
Figure 8 : Manual shut-
off seat valve and
pneumatically operated
changeover seat valve.
The operating
mechanism is
interchangeable between
shut-off and change-over
seat valves.
Figure 7 : The valve
plug position indicator
and control unit is fitted
on top of the actuator.
BUTTERFLY VALVES
The butterfly valve, figure 6, is a shut-off valve. Two valves must be used to obtain a
change-over function. Butterfly valves are often used for sensitive products, such as
yoghurt and other cultured milk products, as the restriction through the valve is very
small, resulting in very low pressure drop and no turbulence. It is also good for high
viscosities and, being a straight-through valve, it can be fitted in straight pipes. The
valve usually consists of two identical halves with a seal ring clamped between them.
A streamlined disc is fitted in the centre of the valve. It is usually supported by bushes
to prevent the stem from seizing against the valve bodies. With the disc in the open
position, the valve offers very low flow resistance. In the closed position the disc seals
against the seal ring. Another type of the butterfly valve is the “sandwich” valve. is
the same type of butterfly valve as described above, but it is fitted between two

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flanges welded to the line. Its function is the same as an ordinary butterfly valve.
During operation it is clamped between the flanges with screws. For servicing the
screws are loosened. The valve part can then be pulled out for easy servicing.
Figure 9 : Manually controlled butterfly valve in
open position (left) and in closed

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PUMPS
Demands on processes have grown steadily harder with respect to both the quality of
the products and the profitability of the processes. Formerly it was often possible to
allow liquids to flow through a plant by gravity. Nowadays they are forced through
long pipelines with many valves, through heat exchangers, filters and other equipment
which often have high pressure drops. The flow rates are frequently high. Pumps are
therefore used in numerous parts of a plant, and the need to have the right pump in the
right place has become increasingly important. Many problems may arise; they can be
summarised under the following headings:
• Pump installation
• Suction and delivery lines
• Type and size of pump required should be selected with regard to:
– flow rate
– product to be pumped
– viscosity
– density
– temperature
– pressure in the system
– material in the pump
Typical dairy pumps are the centrifugal, liquid-ring and positive displacement pumps.
The three types have different applications. The centrifugal pump is the type most
widely used in dairies.
CENTRIFUGAL PUMPS
The centrifugal pump is the most commonly used pump in the dairy industry and
should be selected if it is suitable for the application in question. The reason for this is
that a centrifugal pump is usually cheaper to purchase, operate and maintain, and is
also the most adaptable pump for different operating conditions The centrifugal pump
can be used for pumping of all liquids of relatively low viscosity which do not require
particularly gentle treatment. It can also be used for liquids containing relatively large
particles, provided of course that the particle size does not exceed the dimensions of
the impeller channel.

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A disadvantage of the centrifugal pump is that it cannot pump aerated liquids; it
“loses prime” and stops pumping. It must then be stopped and primed – filled with
liquid – and started again before it can continue pumping. Consequently the
centrifugal pump is not self-priming and the suction line and pump casing must be
filled with liquid before it can operate. The installation should therefore be carefully
planned. The liquid entering the pump is directed to the centre (eye) of the impeller
and is set in circular motion by the impeller vanes, as in figure 7. As a result of the
centrifugal force and the impeller motion the liquid leaves the impeller at a higher
pressure and velocity than at the impeller eye. The velocity is partly converted into
pressure in the pump casing before the liquid leaves the pump through the outlet
connection. The impeller vanes form channels in the pump. The vanes are normally
curved backward, but may be straight in small pumps.
LIQUID RING PUMPS
Liquid-ring pumps, figures 8 and 9, are self-priming if the casings are at least half
filled with liquid. They can then handle liquids with a high gas or air content. The
pump consists of an impeller with straight radial vanes (4) rotating in a casing, an
inlet, an outlet and a drive motor. From the inlet (1) the liquid is led between the
vanes and accelerated out towards the pump casing where it forms a liquid ring with
essentially the same speed of rotation as the impeller.
Figure 14 : Liquid-ring pump.
Figure 10 : Flow principle in a centrifugal pump.

35 | P a g e
There is a channel in the wall of the casing. It is shallow at point 2 and becomes
progressively deeper and wider as it approaches 3 and then gradually becomes
shallow again to point 6. As the liquid is transported by the vanes, the channel is also
filled, increasing the volume available for the liquid between the vanes. This results in
a vacuum in the centre, which causes more liquid to be drawn into the space from the
suction line. Once point 3 has been passed, the volume between the vanes is reduced
as the channel becomes more shallow. This gradually forces the liquid towards the
centre and increases the pressure and liquid is discharged through port 7 to pump
outlet 5. Air in the suction line will be pumped in the same way as the liquid.
Applications
Liquid-ring pumps for the dairy industry are used where the product contains large
quantities of air or gas, and where centrifugal pumps therefore cannot be used. The
clearances between impeller and casing are small, and this type of pump is therefore
not suitable for handling abrasive products. A common application is as a CIP return
pump for cleaning solution after a tank, as the CIP solution contains normally large
amounts of air
POSITIVE DISPLACEMENT PUMPS
This group of pumps works on the positive displacement principle. They are divided
into two main categories: rotary pumps and reciprocating pumps. Each category
includes several types. The principle of a positive displacement pump is that for each
revolution or each reciprocating movement, a definite net amount of liquid is pumped,
regardless of manometric head, H. However, at lower viscosities there may be some
“slip”, internal leakage, as the pressure increases. This will reduce the flow per
revolution or stroke. The slip is reduced with increased viscosity. Throttling the outlet
Figure 15 : Working principle of a self-priming liquid-ring
pump.
1. Suction line
3. Deep channel
5. Pump outlet
7. Discharge port
2. Shallow channel
4. Radial vanes
6. Shallow channel

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of a positive displacement pump will increase the pressure dramatically. It is therefore
important that:
1. no valve after the pump can be closed
2. the pump is fitted with a pressure relief valve, built into the pump or as a
by-pass valve.
LOBE-ROTOR PUMPS
The lobe-rotor pump, figure 10, has two rotors, usually with 2 – 3 lobes each. A
vacuum is created at the inlet when the rotors rotate. This vacuum draws the liquid
into the pump. It is then moved along the periphery of the pump casing to the outlet.
There the volume is reduced and the liquid forced out through the outlet. The course
of events is illustrated in figure 11. The rotors are independently driven by a timing
gear at the back of the pump. The rotors do not touch each other or the pump casing,
but the clearances between all parts in the pump are very narrow.
Figure 19 : Positive displacement pump of the lobe-rotor
type with geared motor assembled on a frame.
Applications
This type of pump has 100% volumetric efficiency (no slip)
when the viscosity exceeds approximately 300 cP. Because of
the sanitary design and the gentle treatment of the product,
this type of pump is widely used for pumping cream with a
high fat content, cultured milk products, curd/whey mixtures,
etc.
Figure 20 : Lobe-rotor pump
principle.

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ECCENTRIC-SCREW PUMPS
This pump is tighter than the lobe rotor pump for lower viscosity products. It is not
considered quite as hygienic as the lobe-rotor pump, but handles the pumped product
gently. The range of application is the same as that of the lobe-rotor pump. The
eccentric-screw pump, figure 6.7.14, cannot be run dry, even for afew seconds,
without being damaged.
Figure 21 : Eccentric-screw pumps

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HOMOGENIZER
HOMOGENISATION THEORIES
Many theories of the mechanism of high pressure homogenisation have been
presented over the years. For an oil-in-water dispersion like milk, where most of the
droplets are less than one mm (10–6 m) in diameter, two theories have survived
Together they give a good explanation of the influence of different parameters on the
homogenising effect.
The theory of globule disruption by turbulent eddies (“micro whirls”) is based on the
fact that a lot of small eddies are created in a liquid travelling at a high velocity.
Higher velocity gives smaller eddies. If an eddy hits an oil droplet of its own size, the
droplet will break up. This theory predicts how the homogenising effect varies with
the homogenising pressure. This relation has been shown in many investigations. The
cavitation theory, on the other hand, claims that the shock waves created when the
steam bubbles implode disrupt the fat droplets. According to this theory,
homogenisation takes place when the liquid is leaving the gap, so the back pressure
which is important to cavitation is important to homogenisation. This has also been
shown in practice. However, it is possible to homogenise without cavitation, but it is
less efficient.
The effect of homogenisation on the physical structure of milk has many,
Advantages:
• Smaller fat globules leading to no cream-line formation,
• Whiter and more appetizing colour,
• Reduced sensitivity to fat oxidation,
• More full-bodied flavour, better mouths feel,
• Better stability of cultured milk products
Figure 22 : At homogenisation the milk is
forced through a narrow gap where the
fat globules are split.

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However, homogenisation also has certain Disadvantages:
• Homogenised milk cannot be efficiently separated.
• Somewhat increased sensitivity to light – sunlight and fluorescent tubes –can
result in “Sunlight flavour” (see also chapter 8, Pasteurised milk products).
• Reduced heat stability, especially in case of single-stage homogenisation, high
fat content and other factors contributing to fat clumping.
• The milk will not be suitable for production of semi-hard or hard cheeses
because the coagulum will be too soft and difficult to dewater.
The homogeniser in a processing line
In general the homogeniser is placed upstream, i.e. before the final heating section
in a heat exchanger. Typically in most pasteurisation plants for market milk
production, the homogeniser is placed after the first regenerative section.
In production of UHT milk the homogeniser is generally placed upstream in
indirect systems but always downstream in direct systems, i.e. on the aseptic side
after UHT treatment. The homogeniser then is of aseptic design with special
piston seals, packings, sterile condensate condenser and special aseptic dampers.
However, downstream location of the homogenisers is recommended for indirect
UHT systems when milk products of fat content higher than 6 – 10% and/or with
increased protein content are going to be processed. The reason is that with
increased fat and protein contents, fat clusters and/or agglomerates (protein) form
at the very high heat treatment temperatures. These clusters/agglomerates are
broken up by the aseptic homogeniser located downstream.
Figure 23 : The homogenizer is a large
high-pressure pump with a
homogenizing device.
1. Crankcase
2. Pistons
3. Damper
4. Pump block
5. Homogenization device, first stage
6. Homogenization device, second
stage
7. Main drive motor
8. V-belt transmission
9. Hydraulic pressure setting system

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Formula for output of standardized milk:
Qp = Plant capacity, l/h
Qsm = Output of standardised milk, l/h
Qh = Homogeniser capacity, l/h
frm = Fat content of raw milk, %
fsm = Fat content of standardised milk, %
fcs = Fat content of cream from separator, %
fch = Fat content of cream to be homogenised,%

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HEAT EXCHANGER
The following three types of heat exchangers are the most widely used
nowadays:
• Plate heat exchanger
• Tubular heat exchanger
• Scraped-surface heat exchanger
PLATE HEAT EXCHANGERS
Most heat treatment of dairy products is carried out in plate heat exchangers. The
plate heat Exchanger (often abbreviated PHE) consists of a pack of stainless steel
plates clamped in a frame. The frame may contain several separate plate packs –
sections – in which different stages of treatment such as preheating, final heating and
cooling take place. The heating medium is hot water, and the cooling medium cold
water, ice water or propyl-glycol, depending on the required product outlet
temperature. The plates are corrugated in a pattern designed for optimum heat
transfer. The plate pack is compressed in the frame. Supporting points on the
corrugations hold the plates apart so that thin channels are formed between them. The
liquids enter and leave the channels through holes in the corners of the plates. Varying
patterns of open and blind holes route the liquids from one channel to the next.
Gaskets round the edges of the plates and round the holes form the boundaries of the
channels and prevent external leakage and internal mixing.
Figure 27 : Principles of flow and heat transfer
in a plate heat exchanger.

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TUBULAR HEAT EXCHANGERS
Tubular heat exchangers (THE) are in some cases used for pasteurisation/ UHT
treatment of dairy products. The tubular heat exchanger, figure 16, unlike plate heat
exchangers, has no contact points in the product channel and can thus handle products
with particles up to a certain size. The maximum particle size depends on the diameter
of the tube. The tubular heat exchanger can also run longer between cleanings than
the plate heat exchanger in UHT treatment. From the standpoint of heat transfer the
tubular heat exchanger is less efficient than a plate heat exchanger. Tubular heat
exchangers are available in two fundamentally different types; multi/mono channel
and multi/mono tube.
Figure 28 : The tubular heat exchanger
tubes are assembled in a compact unit.
SCRAPED-SURFACE HEAT EXCHANGER
The scraped-surface heat exchanger, figure 17, is designed for heating and cooling
viscous, sticky and lumpy products and for crystallisation of products. The operating
pressures on the product side are high, often as much as 40 bar. All products that can
be pumped can therefore be treated. A scraped surface heat exchanger consists of a
cylinder (1) through which the product is pumped in counter current flow to the
service medium in the surrounding jacket. Exchangeable rotors (2) of various
diameters, from 50.8 to 127 mm, and varying pin/blade (3) configurations allow
adaptation to different applications. Smaller diameter rotors allow larger particles (up
to 25 mm) to pass through the cylinder, while larger diameter rotors result in shorter
residence time and improved thermal performance. The product enters the vertical
cylinder through the lower port and continuously flows upwards through the cylinder.
At process start-up, all the air is completely purged ahead of the product, allowing
complete and uniform product coverage of the heating or cooling surface. The

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rotating blades continually remove the product from the cylinder wall, figure 18, to
ensure uniform heat transfer to the product. In addition, the surface is kept free from
deposits. The product exits the cylinder via the upper port. Product flow and rotor
speed are varied to suit the properties of the product flowing through the cylinder. At
shut-down, thanks to the vertical design, the product can be displaced by water with
minimum intermixing which helps assure product recovery at the end of every run.
Following this, completely drainage facilitates CIP and product changeover. As
mentioned above, rotor and blades are exchangeable, an operation which is possible
owing to the automatic hydraulic lift that facilitates raising and lowering the
rotor/blade assembly, figure 19. Typical products treated in the scraped-surface heat
exchanger are jams, sweets, dressings, chocolate and peanut butter. It is also used for
fats and oils for crystallisation of margarine and shortenings, etc. The scraped-surface
heat exchanger is also available in versions designed for aseptic processing. Two or
more vertical type scraped-surface heat exchangers can be linked in series or parallel
to give a greater heat transfer surface depending on the processing capacity required.
Figure 32 : Vertical type
of scraped-surface heat
exchanger.
1 Cylinder
2 Rotor
3 Blade
Figure 34 : Removal
of blades from the
rotor assembly in
lowered position.
.
Figure 33 : Section through a
scrapedsurface
heat exchanger.
1 Rotor
2 Blade
3 Cylinder

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Centrifugal Separator
In a centrifugal separator the disc stack is equipped with vertically aligned distribution
holes. In this fat globules are separated from the milk in the disc stack of a centrifugal
separator. The discs rest on each other and form a unit known as the disc stack. Radial
strips called caulks are welded to the discs and keep them the correct distance apart.
This forms the separation channels. The thickness of the caulks determines the width.
Figure 20 shows how the liquid enters the channel at the outer edge (radius r1), leaves
at the inner edge (radius r2) and continues to the outlet. During passage through the
channel the particles settle outward towards the disc, which forms the upper boundary
of the channel. The velocity w of the liquid is not the same in all parts of the channel.
It varies from almost zero closest to the discs to a maximum value in the centre of the
channel. The centrifugal force acts on all particles, forcing them towards the periphery
of the separator at a sedimentation velocity v. A particle consequently moves
simultaneously at velocity w with the liquid and at sedimentation velocity v radially
towards the periphery. The resulting velocity, is the sum of these two motions. The
particle moves in the direction indicated by vector arrow Vp. (For the sake of
simplicity it is assumed that the particle moves in a straight path as shown by the
broken line in the figure.)In order to be separated, the particle must settle on the upper
plate before reaching point B', i.e. at a radius equal to or greater than r2. Once the
particle has settled, the liquid velocity at the surface of the disc is so small that the
particle is no longer carried along with the liquid. It therefore slides outwards along
the underside of the disc under the influence of the centrifugal force, is thrown off the
outer edge at B and deposited on the peripheral wall of the centrifuge bowl.
Figure 35 : The baffled vessel can
be turned 90° and rotated,
creating a centrifuge bowl for
continuous separation of solid
particles from a liquid.

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CONVEYOR
Whenever question of material handling comes, thought must be given to available
material handling devices, such as, cart, trolleys, fork lift truck, conveyors, etc. All
these devices save labour and time. Not only efficiency is achieved but delays are also
curtailed. Out of all these for constant and organized movement of the product from
one point to another conveyers are the best. Other devices are good for small
operations. Conveyors should be properly laid out, timed and provided with
convenient shut off switches. They should be so located that they do not block
passages. Automatic controls for speed control and stopping in the event of a pile-up
are desirable. The length of conveyor between two pieces of equipment is important
and serves as a storage to aid in synchronizing the speed of the two machines. This
storage function gives the operator a brief period in which to correct minor difficulties
with a machine without stopping the entire line. Conveyor sections can be mounted on
wheels which can be rolled into position to extend the fixed conveyors to load trucks,
if necessary.
Figure 36 : Conveyor
TYPES OF CONVEYORS
Conveyors move cases and cans faster and more efficiently than men and this
increases the proportion of time workers who can spend more time on actual
production work. The most common types of conveyors used in dairy industry are:
1. Chain conveyor
2. Belt conveyor
3. Gravity conveyor (roller conveyor)
4. Wheel conveyor

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CHAIN CONVEYOR
Chain conveyors are the type most widely used in the dairy plant to convey crates,
cans and other packages. Chain conveyors are of three types: (1)above floor type,
(2)infloor type, and (3)on floor type. Regardless of the type, every chain conveyor
system consists of 4 basic parts, namely (1) power uni, (2) conveyor frame, (iii) chain,
and (iv) take up unit.
All complete chain conveyor systems may consist of one or more power units
depending upon the size of the plant and the complexity of the package handling flow
in plant.
Above floor chain conveyors have an open type steel welded or bolted frame. The
chain is pulled along in the hardened steel chain tracks mounted in this frame –
usually foot above the floor. The return chains run in channels mounted in the frame
below the carrying chains. The standard chain height for an above-floor conveyor in
most plants is between 18 and 22 inches. This is because the top of the case is
generally 30 to 36 inches off the floor, which is the most convenient working height
for most washer and filler operators. This type of conveyor is used to convey single
cases and cans. The conveyor frame has side rails that extend up above the top of the
chain to keep the case and can on the conveyor.
The in-floor type conveyor is a double chain conveyor imbedded in the floor. The
infloor type conveyors cost same as above floor type conveyors except that
installation cost is slightly higher because of the necessity of supplying in floor pits
for drives and take up units. Also cost of additional work required to imbed the
conveyor in the floor flush with floor level. The frame consists of a steel plate 1/8 to
3/16 inch thick, formed with channels for the carrying and return chains, so that the
overall width of frame is about 16 inches. The conveyor frame is embedded in the
floor. The two carrying chains are usually ½ inch above the
floor level. The return chain travel is between and below the
carrying chains.
Figure 37 : Chain
conveyors

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In-floor conveyors must be planned in the initial stages, because a floor channel has to
be provided to accommodate them and to house driving motor. The pits for driving
motors are made large enough for cleaning and maintenance and are covered by
removable steel plates or grids. With infloor conveyors, the entire area where the
conveyor is located is free from those conveyors which must be climbed over to get
around the plant.
BELT CONVEYORS
Belt conveyors are used in dairy plants for carrying cases between floors in multistory
plants. These are also used in the dry storage warehouses for unloading warehouse
items from delivery trucks. Belt conveyors are not suited for handling milk cans.
Figure 38 : Belt conveyors
GRAVITY-ROLLER CONVEYORS AND WHEEL CONVEYORS
Gravity-roller conveyors and wheel conveyors are used today to a limited extent.
These conveyors find their use in warehouse and for short sections or lift sections at
the end of power conveyor systems. Wheel conveyors are ideal for warehouse
operations because they are light in weight, portable and are easily moved around in
the ware house.
BOTTLE CONVEYORS
Bottle conveyors are of two types, namely (1) Flat link, and (2) the lateral curve. Both
have a smooth level surface and can be used for either glass or paper bottles. It will be
noted that bottles require slat conveyors to give the necessary area of flat surface for
stability. Bottle conveyor is a type of chain conveyor using chains which may have
from a 1 to a 4 inch pitch. The drive unit is usually of the gear-motor variety located

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at one end of the conveyor and pulling the chain through the system to an idler
sprocket at the other end. The chain runs on a frame between the rails. Conveyors are
installed as per requirement of a particular section.
Figure 39 : Bottle conveyors

CLEAN IN PLANT (CIP)
e
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Cleaning In Place (CIP) system are used for cleaning the equipment used in the
production of beverages, fruit juice, food stuff, dairy products, pharmaceutical product,
and generally all those sector that demand high standard of hygiene and cleanliness.
The CIP system are available in manual and automatic version they enable the
preparation of washing solution and they manage washing processes in a various type
of equipment in fully automated cycle.
The automatic version are equipped with Programmable Logical Control (PLC) with
dedicated software and a touch screen control system and make them extremely easy to
use. Recipes can be saved and numerous parameters (type of washing, temperature,
water and rinsing cycle times, concentrations of acid/alkaline solutions, etc.) can be
selected with the assurance with the absolutely precise compliance with the
specification.

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1. Acid unloading tank(12000 lit), 2. Lye unloading tank (12000 lit), 3. Lye overhead
tank, 4. Acid overhead tank, 5. Acid reactor (15000), 6. Recuperation tank (1000 lit),
7. Lye reactor (15000 lit), 8. Fresh water tank (1000 lit), 9. Hot water tank, 10. Heat
exchanger.
CIP cycles are typically runs either after a processing run that has produced a normal
soiling or changing over a processing line from one product to another. Every CIP cycle
has its own unique set of parameters, so there’s no such thing as a “typical” CIP cycle.
The elements, sequence, and duration of the cleaning process can varied widely from
one system to another, but some common steps are included in most cleaning cycles:
Step 1: Pre- Rinse
Step 2: Caustic wash
Step 3: Intermediate Rinse
Step 4: Acid Wash
Step 5: Final Wash
STEP 1: PRE-RINSE
The Pre-rinse is a very important step in the CIP process because a well-monitored and
a well-executed pre-rinse makes the rest of the wash cycle predictable and repeatable.
It serves the following purpose
 Wets the interior surface of the line and tank
 Remove most of the remaining residue
 Dissolves sugar and partially melts fats
 Provides a non-chemical pressure test of the CIP flow path
Use portable plant water, de-ionized water (DI), water that has been processed through
reverse osmosis (RO), or reuse the final rinse solution from the previous cleaning
sequence. A Turbidity Sensor maybe used to verify that the pre-rinse effectively
removes all solids.

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STEP 2: CAUSTIC WASH (60o
C - 85o
C)
Caustic washes soften fats, making them easier to remove. Also known as caustic soda,
Sodium hydroxide or NaOH, the alkali used in caustic washes have a very high pH.
Concentration as high as 4% maybe used for highly solid surfaces.
Caustic is typically used as the main detergent in most CIP wash cycles. A non-foaming
formulation can help reduce pump cavitation and increase efficiency. It will also
prevent tanks from over filling with foam when the system start to recirculate.
Water saving tips: In many cases, the caustic wash can be returned to its tank and re-
used multiple times, which significantly reduces water, chemical, and energy costs over
a single tank system.
STEP 3: INTERMEDIATE RINSE
Fresh water flushes out residual trace of detergent remaining from caustic wash. Proper
instrumentation during step of CIP cycle, including rinsing, ensures proper cleaning.
Some of the instrument used is as follows.
 Level transmitter and probes monitor tank levels of wash and rinse tanks.
 Flow transmitters ensures optimum flow for spray devices to precisely control
wash and rinse steps.
 Return Conductivity transmitter ensure chemical level of hitting predetermined
set point
STEP 4: ACID WASH
Many dairies use acid washes regularly to remove milk scale, also called “milk stone”.
Acid is also excellent for brightening up discoloured stainless steel by removing
calcified stainless steel. This optional step would occurs after the intermediate rinse and
before final rinse. Acid must be used with caution because they can attack some
elastomers in the system like gaskets or valve seats causing premature degradation or
failure. The acid wash cycle:
 Dissolves mineral scales from hard water deposits and protein residues.
 Neutralizes the system pH.

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Nitric acid is the most commonly used wash for scale removal and pH stabilization after
a caustic wash.
Water saving tips: In a three tank CIP system when a acid wash is not needed the reused
can capture the intermediate wash and use it as an effective pre-rinse for the next
cleaning sequence.
STEP 5: FINAL WASH
Rinse with either DI, RO, or city water to flush residual cleaning agent. In many system
the final rinse water maybe recovered and reused as the pre-rinse solution for the next
cleaning cycle. The residual heat and chemicals it retains from the final rinse will help
make the next pre-rinse effective and economical.
ADVANTAGE OF CIP SYSTEM
 Minimizes mistakes: Automatic cleaning reduces the chance of human error that
can contribute to an unsafe product.
 Keeps employees safe: Reduce chemical exposure by containing cleaning
solution within the system.
 More production time: As less production time is lost to cleaning more time is
spent making product.
 Product Quality: Reliable and repeatable cleaning means suitable product
quality and consistency. Less contamination means fewer product recalls and
higher brand confidence.
 Utility Savings: Water and energy usage is reduced through repeatable cycle
control.

EFFLUENT TREATMENT PLANT (ETP)
SECTION
e
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Effluent treatment is the process of removing contaminants from waste water collected
form the plant. It includes physical, chemical, and biological processes to remove
physical chemical and biological contaminants. Its objective is to produce an
environmentally safe fluid waste stream (or treated effluents) and a solid waste (or
treated sludge) suitable for disposal or reuse (usually as a farm fertilizer) with suitable
technology it is possible to reuse sewage effluents or drinking water although this is
usually only done in place with limited water supply.
Origin of sewage
Sewage is generated and collected from the following operations and sections.
 Water from the CIP process
 Water from washing milk carats
 Water from washing milk dispatch trucks
 Sewage water from toilets
 Water from cleaning milk fat spilled on the floor
This sewage water is collected and transported to the effluent treatment plant that is
located about 200m from the main plant site. The ETP plant treats about 6,00,000
lit/day. The raw sewage all over the plant is collected to collection tank. From where it
is pumped to equalization tank where an air pump, pumps air from the bottom in order
to agitate the water and breaks the bigger fat molecules in into smaller molecules and
agitate it to the surface, this tank also has a second purpose to traps the odour of sewage
water. From equalization tank the sewage is passed to oil and grease removal tank
where oil grease and fat are allowed to come on the surface and are removed and the
remaining sewage is passed to lime mixture tank. Here the softening of water is done
by adding lime into it. It softens the water by forming insoluble salt of magnesium and
calcium. After this it is passed through baffles where these salts are collected and passed
on to tank, where alum is added so that aluminium salts hydrolyze and give a variety of
products including cationic species, which can adsorb on negative charged particles,
and thus neutralize their charge. The particles get destabilized and aggregation occurs.
Over dozing coagulant leads to charge reversal and particles start restabilising. This
aggregated particle are then separated in primary clarifier where the scrapper arm
rotating at the bottom of the clarifier collects the sludge from the bottom and sends it
to sludge collecting tank. Then the sewage water collected in the clarifier is sent to

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aeration tank, where bacteria is added accordingly, these bacteria breaks down oil and
grease macromolecules into simple molecule. This water is then sent to secondary
clarifier and the clarified water is then used for agricultural purposes. The pH of water
from lime adding tank is maintained between 5-8 pH, as it is the operating range for
alum. In aerationtank the amount of bacteria is maintained byrecirculating pump, when
the amount of bacteria is less the pump is started and vice-versa. The sludge collected
is used as a fertilizer in agriculture process and it is also sent to fertilizer industry.
Collection tank
Flow meter
Equalization tank
Oil skimmer
Flash mixer 1
Flash mixer 2
Primary Clarifier
Aeration Tank
Secondary clarifier
Treated water sump
Air compressor
Slug drying bed
Sludge to SBD
Lime
Oil collection
Alum
Aeration wash out

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TREATED EFFLUENT CHARACTERISTICS
Sr. no. Parameter Values
1. Flow 60 m3/day
2. pH 6.5-8.5
3. BOD < 30 mg/l
4. COD < 100 mg/l
5. Suspended Solids < 100 mg/l
6. Oil and Grease < 10 mg/l

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 Cleaning of Pasteurized cream tank (D21000)
 Pre-Rinse : Fill the tank
 Time : 30 sec
 Pre-Rinse : Empty the tank
 Time : 200 sec
 Temperature : 320 C
 Return Conductivity : 2.4 mS cm-1
 Pre-Rinse : Fill Circuit
 Time : 60 sec
 Temperature : 32.40 C
 Pre-Rinse : Circulation
 Time : 300 sec
 Acid : Fill the tank
 Time : 50 sec
 Temperature : 37.90
C
 Acid : Empty the tank
 Time : 200 sec
C
 Return Conductivity : 4 mS cm-1
 Acid : Fill Circuit
 Time : 60 sec
 Acid : Front mix zone
 Time : 60 sec
 Acid : Circulation
 Time : 300 sec
 Temperature : 680
C

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 Final Rinse : Fill the tank
 Time : 50 sec
 Temperature : 710 C
 Final Rinse : Empty the tank
 Time : 200 sec
 Temperature : 730
C
 Final Rinse : Fill the circuit.
 Time : 60 sec
C
 Final Rinse : Front mix zone
 Time : 30 sec
 Final Rinse : Circulation
 Time : 300 sec
C
 Final Drain : Drain Circuit
 Time : 30 sec
Conclusion
 Total time taken to clean the tank D21000 = 32 min
 The return conductivity increases that shows TDS increases
 An effective cleaning is said to be done when conductivity value is between
70 – 80 mS cm-1
for acid wash and 2 – 4 mS cm-1
for water rinse.

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? Surplus cream
stream,fat 2%
Separator
 Finding the volume of cream (40 % fat) coming out of separator to be
mixed with the stream of skimmed milk, so that the fat of the skimmed
milk increase to 3% and the feed to the separator is 20,000 l/hr, 5% fat
and skimming efficiency is 98%.
Feed: 20000
l/r, 5% Skimmed milk
fat 2%
Cream stream
Fat 40%
Skimmed milk
fat 3%
Given
Feed : 20,000 l/hr; feed fat% = 5%; skimming efficiency = 98%; cream fat% = 40%;
Now,
calculating skimmed milk flow rate (S) and cream flow rate (X)
Total flow equation across the separator is
X + S = F --------- (i)
Fat flow across the separator is
0.4 X + 0.02 F = 0.05 (20,000)---------- (ii)
Solving Equation (i) and (ii), we get,
X = 18,421.05 l/hr; S = 1579 l/hr
Now to get the skimmed milk fat concentration from 2% to 3%, some V
amount of 40% fat cream is to be mixed with 2% fat skimmed milk
Therefore V is given as

62 | P a g e
0.03 =
0.02 ×18421.05 + 0.4 × V
18421.05 + V
V = 497.86 l/hr
Therefore 497.89 lit of cream is to be added to 18421.05 lit of skimmed to
increase fat concentration to 3%.
 Finding the sediment velocity in particle separator.
Given Data:
Motor speed = 5100 RPM,
Size of particle, d = 5 µm,
Viscosity = 2 × 10-3
kg m-1
s-1
Difference in density (ρp-ρl) = 48
kgm-3
Radius, r = 0.2m
Velocity = ?,
for centrifugal the velocity is given by the following formula
V = d2
×(ρp−ρl) × r × ω2
18𝑛
=
(5×10 −6)2 × 48 × 0.2 × (534.07)2
18 × 2 × 10−3
= 0.0019 m s-1

63 | P a g e
REFRENCES
 Dairy Processing Handbook, Gösta Bylund.
 Flow Diagram – Visual Paradigm
 Dairy overview – Wikipedia
 A Dictionary of Dairying, J.G. Davis
 Development of Dairy Chemistry, P.H. Fox

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