i

Table of contents

TITLE PAGE

Table of contents i

List of Tables ii

List of Figures iii

List of Abbreviations iv

1. Introduction 1

2. Description of dairy industry 1

2.1 Production statistic 1

2.2 Importance of the industry 4

2.3 Presentation of production process 4

3. Environmental issues of dairy industry 6

3.1 Main pollution sources in dairy products 7

3.2 Characteristics of pollution 8

4. Conventional end of pipe treatment and inline treatment system 11

4.1 Conventional end of pipe treatment 11

4.2 Inline treatment system 12

5. Possible process modification & cleaner production aspects 12

5.1 Waste minimization 12

5.2 Process control 13

6. Case study Meiji dairy industry 17

6.1 Waste segregation 17

6.2 Waste sampling and monitoring 17

6.3 Waste treatment plant layouts 18

6.4 Typical cost information 20

6.5 Simple unit process material balance calculation 21

6.6 Major O & M issues related to wastewater treatment plant 25

Reference 26

ii

List of Tables

Table Title Page

Table 2.1 Input and output of dairy industry 5

Table 2.2 Classification of packaging and distribution systems 5

Table 3.1 Wastewater characteristic for the dairy industry 8

Table 3.2 The air emissions from gas-oil combustion and cleaning process 9

Table 3.3 Industry benchmark of energy and resource consumption 10

for dairy processing facilities 10

Table 3.4 Typical noise limits in effected residential areas (dBA) 10

Table 4.1 Air emission control Efficiency of Venturi Scrubber 12

Table 5.1 Waste minimization strategies 13

Table 5.2 Cleaner Production Assessment and Techniques in Liquid milk production 15

Table 6.1 Monitoring plan of air pollution 17

Table 6.2 Monitoring plan of wastewater 18

Table 6.3 Typical cost of milk production process 20

Table 6.4 Unit operation and construction cost 20

Table 6.6 Major O & M issues related to wastewater treatment plant 25

iii

List of Figures

Figure Title Page

Figure 2.1 Milk production growth between 2000 and 2013 2

Figure 2.2 Per capita milk consumption versus development in world population 2

Figure 2.3 Major World Dairy Exporters 2

Figure 2.4 Composition of dairy products 2

Figure 2.5 The demand for milk and dairy products in Asia 3

Figure 2.6 Where will dairy production gains be located over the next decade 3

Figure 2.7 The import and export of dairy products of Thailand in 2010 3

Figure 2.8 After a downward correction prices continue rising in nominal terms 4

Figure 2.9 Basic diagram for milk process 6

Figure 3.1 Environmental pollution sources 8

Figure 4.1 Components of a conventional dairy processing wastewater treatment 11

Figure 6.1 Solvent recovery in CIP process 17

Figure 6.2 Wastewater treatment plant layout 19

Figure 6.3 Mass balance for whole process 21

Figure 6.4 Mass balance for separator and standardization 22

Figure 6.5 Mass balance for tie compound (fat) 19

iv

List of Abbreviations

BMP Butter Milk Powder

BOD Biological Oxygen Demand

COD Chemical – biological Oxygen Demand

CIP Clean In Place

COWI International consulting group, specializing in engineering, environmental

science and economics, based in Lyngby, Denmark.

DAF Dissolved Air Flotation

DLD Department of Livestock Development

DPO Dairy Farming Promotion Organization

FAO Food and Agriculture Organization

GDP Gross Domestic Product

IFC International Finance Corporation

LDC Least Developed Country

OECD Organization for Economic Co-operation and Development

SMP Skim Milk Powder

UN United Nations

UNEP United Nation

UNIDO United Nations Industrial Development Organization

USDA United States Department of Agriculture

US EPA US Environmental Protection Agency

WMP Whole Milk Powder

WWTP Waste Water Treatment Plant

1

1. Introduction

The dairy sector plays an economically important part in the agricultural sectors in most

industrialized and also many developing countries. Global demand for dairy is continuing to

grow because of population growth, rising incomes, urbanization and westernization of diets.

Asia continues to be the major growth market globally accounting for 34 per cent of all dairy

imports in 2011. Asia accounts for 53 per cent of the world’s SMP (Skim Milk Powder) and

40 per cent of the world’s WMP (Whole Milk Powder) imports. Consumer products include

branded dairy products, such as fresh milk, flavored milk, nutritional milk powders, cheese,

yoghurt, butters, creams and ice cream. Consumer products are produced either from domestic

milk supply or imported dairy ingredients.

Today, industry consolidation and the shift toward mega-farms continue. Sustainability and

traceability remain top-of-mind concerns. The overall consumption of dairy products has risen

but the consumers tend to choose competitive beverages, such as protein and energy drinks

and plant-based products – almond, soy and rice milk.

Like any other industrial activities, dairy processing inevitably leads to the production of

wastes. In this paper, the critical link between milk processing operations and waste

generation is examined and suitable waste reduction and management options are discussed.

The case of a hypothetical skimmed milk factory is presented to provide specific examples of

application of waste abatement and management strategies.

2. Description of dairy industry

2.1 Production statistic

2.1.1 The world dairy industry situation

The growth of world milk production slowed down in 2013. Compared to last year it increased

by only 1.5% to 781 million tones. This rate is rather small in comparison to 2011 versus 2010

(2.8%) and much lower than the compound annual growth rate (2.4%) observed during the

period from 2000 to 2009 (Figure 2.1). Poor return from milk production and high input cost

seemed to have discouraged farmers in many parts of the world.

Based on the UN world population can estimate population which amounting more than 7.1

billion people, global per capita consumption of milk in 2012 was 109.1 kg. Because of the

continuous growth in world population, the global per capita milk consumption in the period

between 2005 and 2013 grew by no more than 8% (Figure 2.2). Over the last decade,

consumer eating habits have gradually shifted toward single-serve portion (that can be eaten

on-the-go) as well as healthier food choices. This trend has given rise to new dairy products

such as Greek yogurt, which is lower in fat and sugars than traditional yogurt and is available

in single serving.

2

2.1.2 Dairy industry in Asia

The Organization for Economic Co-operation and Development (OECD) and the Food and

Agriculture Organization (FAO) project that the strongest gains in dairy production and

consumption over the coming decade will take place in Asia. Increasing incomes and a

continuation in changing consumption patterns are expected to translate into a nearly 120

million tones increase in world milk production, up to 20 percent to 803 million tons by 2017.

Over half of the output gains, or 63 million tones, will be produced in Asia, particularly China

and India, two countries which are expected to account for a respective 16 and 20 percent of

the global increase (FAO, 2009).

Figure 2.1 Milk production growth between

2000 and 2013 (Source: The World Dairy

Situation, 2013)

Figure 2.2 Per capita milk consumption

versus development in world population

(Source: The World Dairy Situation, 2012)

Figure 2.3 Major World Dairy Exporters

(Source: U.S.DA FAS)

Figure 2.4 Composition of dairy products

3

2.1.3 Dairy industry in Thailand

Thai dairy farming was initially run as a project by the Ministry of Agriculture for the Royal

Thai Government. The Department of Livestock Development (DLD), the Dairy Farming

Promotion Organization of Thailand (DPO) and the Nongpo Dairy Cooperative have been

responsible for intensively promoting dairy farming and the dairy sector ever since.

The total amount of raw milk production in 2012 was 1,064,270 tons. About 95-97 percent

of this production was processed for drinking milk. The remaining 3-5 percent was

processed for cheese. Thailand also imports other milk products, especially skimmed milk

powder, which in 2010 was valued at 59,357 tons. Thailand also exports milk products, such

as sweetened condensed milk, sterilized drinking milk and evaporated milk, to Cambodia,

Singapore, Philippines, Myanmar, Laos, Indonesia and other neighboring countries (DLD,

2012).

Figure 2.5 The demand for milk and dairy

products in Asia (Source: FAO)

Figure 2.6 Where will dairy production

gains be located over the next decade

(Source: OECD, FAO)

Figure 2.7 The import and export of dairy products of Thailand in 2010 (Source: DLD, 2012)

4

2.2 Importance of the industry

Dairy industry is a highly labor intensive industry and it provides a lot of employment hence

widely contributing to the GDP of the nation. Moreover, westernization of diets has resulted in

the increasing market of the dairy industry. The dairy sector is one of the fastest growing

sector and over the next 10 years, world milk production is projected to increase by 153 Mt, of

which major portion is anticipated to be contributed by developing countries. The average

growth rate for the projection period is estimated at 1.9%, slightly below the 2.1% level

witnessed in the last decade (OECD and FAO, 2011)

Figure 2.8 After a downward correction prices continue rising in nominal terms

(Source: OECD and FAO Secretariats, 2011)

Dairy products have a strong market in developing nation like North Africa, Middle East and

East Asia and in the mature markets like European Union, United State and Russia. There is a

huge disparity of the per capita consumption pattern of the milk product among LDC (50

kg/person/year), developing countries (kg/person/year) and developed nation (200

kg/person/year) which further increases the investment potential and future opportunities for

both the domestic and global dairy sectors (OECD and FAO, 2011).

2.3 Presentation of production process

Products

There are many categories from dairy industry, based on raw material. The USDA

identifies four basic classes of milk use:

Fluid milk products

Cream products, cottage cheese, ice cream, and other food uses

Hard and spreadable cheeses

Butter and dried milk products

5

Raw material

Raw fluid milk is collected from individual dairy farms where milk is temporarily

stored until transport. The raw milk is delivered to the processing plant by truck. The

incoming tanker milk delivered to the processing/production facility is routinely checked for

quality and safety factors, including biological, chemical, and physical contaminants: odors,

temperature, appearance, acidity, bacterial counts, drug residues, antibiotics, herbicides, and

pesticides.

Inputs and outputs

Inputs and outputs associated with milk production are shown in the table below. Data

are provided per kg of milk product at the dairy's gate without packaging. Table 2.1 shows the

input and output of dairy industry.

Table 2.1 Input and output of dairy industry

Unit

Quantity

Skimmed

milk

Low fat

milk Full milk Minimilk

Inputs Raw Milk kg 1.12 1.08 1.02 1.11

Electricity Whr 54.00 54.00 54.00 54.00

Heat Whr 50.00 50.00 50.00 50.00

Water L 0.70 0.70 0.70 0.70

Outputs Milk kg 1.00 1.00 1.00 1.00

Cream kg 0.12 0.08 0.02 0.11

(Source: Material/Food from industry/ from dairies)

Packaging materials

The package selection will have to satisfy the requirements dictated by existing

economic limits, production and distribution efficiency, retailing objectives, consumer

considerations and ecological aspects. The classification of packaging and distribution systems

of liquid milk is shown in table 2.2.

Table 2.2 Classification of packaging and distribution systems

Liquid milk

Returnable containers Single service containers Dispatch by

tankers to vending

machines

Glass

bottles

Plastic

bottles Cans Cartons Sachets

Plastic

bottles

Pasteurized √ √ √ √ √ √ √

Sterilized √ √

UHT √ √ √

(Source: http://www.fao.org/DOCREP/003/X6511E/X6511E01.htm)

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Production process (refer to appendix A for explanation)

3. Environmental issues of dairy industry

As many food processing, dairy processing industries associate with some major

environmental issues: (1) large amount of water consumption, (2) high volume of wastewater

produced, (3) high energy consumption, (4) air emissions from drying operations and (5) solid

waste production. In addition, odors from wastewater treatment plant operations and noise

from equipment may also be concerned. (Please refer to Appendix B)

Separation and

Standardization

Pasteurization

Milk receipt, filtration and clarification

Cream

Skimmed milk

Storage

Homogenization

Deodorization

Packaging and cold storage

Distribution

Butter

churning

Packaging and freezing

Skimmed milk

Storage

Cream

Buttermilk

Butter

Butter

Cream

Skimmed milk

Figure 2.9 Basic diagram for milk process (Source: COWI, 2000)

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3.1 Main pollution sources in dairy products

Milk receiving

Wastewater is from tank, truck and storage tank washing, pipe line washing and

sanitizing. It contains milk solids, detergents, sanitizers and milk wastes.

Whole milk products

Wastewater is mainly produced during cleaning operations. Especially when different

types of product are produced in a specific production unit, clean-up operations between

product changes are necessary. In developing countries, the main problem is pollution through

spoilage of milk.

Cheese/Whey/Curd

Wastewater results mainly from the production of whey, wash water, curd particles etc.

Cottage cheese curd for example is more fragile than rennet curd which is used for other types

of cheese. Thus the whey and wash water from cottage cheese may contain appreciably more

fine curd particles than that from other cheeses. The amount of fine particles in the wash water

increases if mechanical washing processes are used.

Butter/Ghee

Butter washing steps produce wash water containing buttermilk. Skim milk and

buttermilk can be used to produce skim milk powder in the factory itself or itself or these

materials may be shipped to another dairy food plant by tank truck. The continuous butter

production process materially reduces the potential waste load by eliminating the buttermilk

production and the washing steps (Harper et. al., 1971).

Milk powder

Environmental problems are caused by high energy consumption (emission of CO2,

CO etc.), by cleaning and by emission of fine dust during the drying process.

Condensed milk/Cream/Khoa

Environmental problems related to the production of condensate are mainly caused by

the high energy consumption during the evaporation process. The main suspended solids

mentioned in the literature are coagulated milk and fine particles of cheese curd.

Major waste generation in the processes includes:

Washing, cleaning and sanitizing of pipelines (metals), pumps, processing

equipment, tanks, tank, trucks and filling machines.

Start-up, product change over and shut down of HTST and UHT pasteurizers

Breaking down of equipment and breaking of packages resulting in spilling during

filling operations

Lubrication of casers, stackers and conveyors

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3.2 Characteristics of pollution

Wastewater

Wastewater contains high amounts of organic loading, oil and grease, suspended solids,

nitrogen and phosphorus content. The pH depends on the chemical or detergent use in

cleaning operations and pathogens from contaminated materials or production processes.

Table 3.1 Wastewater characteristic for the dairy industry

Parameter Average

COD (mg/L) 2000

BOD (mg/L) 1500

Fat (mg/L) 150

Nitrogen (mg/L) 100

Phosphorus (mg/L) 30

(Source: Danish EPA, 1971)

From Table 3.1, it is inevitable that the dairy industry produces biodegradable waste that

consist high amount of BOD and fat (oil and grease). (Details on appendix C)

Figure 3.1 Environmental pollution sources

9

Solid waste

Main sources of the wastes were from production processes and product losses (e.g. milk

spillages liquid whey and buttermilk), grid and filter residues, sludge from centrifugal

separators and wastewater treatment, and packaging waste (e.g. discarded cuts, spent ripening

bags, wax residues from cheese production).

The amount of sludge production in an aerobic process is about 0.5 kg per kg of removed

COD and in an anaerobic process is about 0.1 kg per kg of removed COD. (US EPA, 1971).

Air pollution

Exhaust Gases emissions from the combustion of gas and fuel oil or diesel in

turbines, boilers, compressors and other engines for power and heat generation. The

characteristics of air emissions from a dairy industry would depend on the type of fuel.

Emissions of dust during dairy processing activities include fine milk powder residues

in the exhaust air from the spray drying systems and bagging of product and type of fuel.

The major sources of odor emissions in dairy processing facilities are related to on-

site wastewater treatment facilities, in addition to fugitive odor emissions from filling /

emptying milk tankers and storage silos.

In dairy industries, air pollution is mainly caused by the energy consumption. The main

discharged gasses are CO2, CO, NOx and SO2.

Table 3.2 The air emissions from gas-oil combustion and cleaning process

Process Air emission

(kg/ton processed milk)

Heating by burning gas or oil CO 0.03

CO2 92

NOx 0.1

SO2 0.05

Producing milk powder Fine dust 0.39

Cleaning VOC 0.05

(Source: FAO, 1996)

Energy consumption

Electricity is used for the operation of machinery, refrigeration, ventilation, lighting and the

production of compressed air. Like water consumption, the use of energy for cooling and

refrigeration is important for ensuring good storage quality of dairy products and storage

temperatures as specified by regulation. Thermal energy, in the form of steam, is used majorly

for heating.

Dairy industry utilizes fossil fuel for the purpose of energy generation which leads to the air

pollution and emission of greenhouse gasses, making dairy industry vulnerable cause of global

warming.

10

Table 3.3 Industry benchmark of energy and resource consumption

for dairy processing facilities

Milk Product

Resource and energy consumption

Water

(L/L processed milk)

Energy

(kWh/ L processed milk)

Wastewater

(L/L processed milk)

Market milk and cultured

products 1.0-1.5 0.1-0.2 0.9-1.4

Cheese and whey 1.4-2.0 0.2-0.3 1.2-1.8

Milk powder, cheese, and

(or) liquid products 0.8-1.7 0.3-0.4 0.8-1.5

Ice cream 4.0-5.0 0.8-1.2 2.7-4.0

(Source: IFC-World Bank, 2007)

Noise

Generally, most milk processing plants are located in country areas where there are no

residential statutory requirements for industry but EPA may set noise targets based on the

State Environment Protection Policy and guidelines and may use discretion in each particular

case. In addition, there may be local government regulation on industrial noise. The principle

causes of continuous noise are: air discharges from drier stacks, heater fans, ventilation,

boilers, pumps, cooling towers, refrigeration units, and aerators on aerated lagoons.

Truck movements to and from the site or in streets are a source of noise, as are refrigeration

compressors on trucks. Intensity of the noise increases during the night transportation shift.

Noise operations at dairy plants include milk drying – which requires high airflows – and the

movement of transport vehicles to and from the site. Depending on the distance to sensitive

receptors such as residential areas, suitable noise suppression or abatement measures – such as

noise silencers on equipment, enclosure of outdoor equipment, concrete housing for

mechanical plant, and mufflers on transport vehicles – may be required.

Table 3.4 Typical noise limits in effected residential areas (dBA)

Time of day (hours) Day

(6am – 10pm)

Evening

(6pm – 10pm)

Night

(10pm- 7am)

Mainly residential 50 – 54 44 – 48 39 – 43

Residential

Commercial or

Industrial

54 – 59 48 – 52 39 – 43

Commercial 56 – 59 52 – 57 47 – 52

Industrial 63 – 68 57 – 71 52 - 56

(Source: The State Environmental Protection Policy (Control of Noise from Commerce,

Industry and Trade, No. N-1)

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4. Conventional end of pipe treatment and inline treatment system

4.1 Conventional end of pipe treatment

Solid Wastes Disposal:

Solid waste generated by dairy plants included packaging waste such as cardboard, cartons,

paper and plastic, and organic waste such as sludge and reject product (UNEP, 2004).

However, the main solid waste produced by the dairy industry is the sludge resulting from

wastewater purification. In aerobic systems the sludge production is about 0.5 kg per kg of

removed COD and in anaerobic systems about 0.1 kg per kg of removed COD (US EPA,

1971). Conventional solid waste management approach deals with the collection of waste

without any source separation and finally disposing it to the landfill using municipal collection

system. Sludge cake are also sent to the landfill after reducing the moisture out of it.

Wastewater Treatment:

In dairy industry different water intensive manufacturing processes produces a large amount of

effluents which consist of high organic load. This organic load is basically constituted by milk

(raw material and dairy products), reflecting an effluent with high levels of COD, BOD, oils

and grease, nitrogen and phosphorus. Moreover, CIP (automated) - discards rinse waters with

pHs varying between 1.0 and 13.0, further complicating the question of treatment (Brião,

2000). BOD is directly related to milk wastes (90% to 94% of the effluent BOD), and in some

cases losses can reach 2% of the volume processed by the industry (UNIDO, 1999).

Typical end of pipe treatment of the dairy waste water consist of the waste water treatment

plant designed to meet the effluent standard. A typical or conventional WWTP consist of the

‘screen’ to remove coarse milk solid followed by ‘Parshall flow meter’ to measure the flow of

wastewater, ‘equalization and neutralization tank’ to balance the flow and pH; oil and grease

removal mechanisms such as ‘Dissolved Air Flotation (DAF)’to remove the oil and grease;

‘anaerobic or aerobic activated sludge process’ to reduce the BOD, tertiary treatment unit like

‘wetland’, ‘polishing pond’, ‘facultative lagoon’, etc. and finally ‘Sludge thickening’ and

‘Sludge dewatering’ to convert the sludge into solid waste which can either be sent to the

landfill or can be incinerated. The industries need to comply with the effluent standard before

discharging it to the stream. (Effluent standard of different countries: appendix D)

Screening

Oil and

Grease

Removal

Aerobic or

Anaerobic

Treatment Discharge

Equalization/

Neutralization

Tank

Figure 4.1 Components of a conventional dairy processing wastewater treatment

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Air Emission Control:

Conventional end of pipe treatment of the air emission for the dairy are either by increasing

the stack height and using pollution control equipment like cyclone, electrostatic precipitators

and scrubbers. Venturi Scrubber is one of the control equipment generally used in dairy

industry for the control of dust and gaseous pollutants. Caustic soda is used for the spray

which removes the gaseous pollutants. Cyclone with demister follows the scrubber. Removal

efficiency is shown below. The main conventional source of pollutant in the dairy industry is

boiler for which a huge amount of energy is consumed in the form of combustion of biomass

or coal (traditionally used) resulting in the production of SOx, NOx, PM and CO2 as major

pollutant and VOC and minor pollutant. However, dairy accounts less air pollution in

comparison to other industries.

Table 4.1 Air emission control Efficiency of Venturi Scrubber

(Source: Design of Air Pollution Control Systems by Dr. N. T. Kim Oanh)

4.2 Inline treatment system

The inline system is suggested considering the use of low-waste technology, use of less

hazardous substances, recovery and recycling of waste, low pay back period, principle of

precaution and prevention and occupational health of the workers. (Detail of possible inline

treatment method: Appendix E)

5. Possible process modification & cleaner production aspects

Cleaner Production is a proactive approach to industrial pollution management. When applied

to processing, cleaner production implies minimization of raw materials and energy use, the

elimination of toxic raw materials, and the reduction in the quantities and toxicity of wastes

and emissions. In the dairy industry, milk production typically consumes large quantities of

water and energy and discharges significant loads of organic matter in the effluent stream.

Toxicity elimination is irrelevant in dairy industry. Thus, successful application of cleaner

production procedure in the production will contribute to use of water and energy resources,

increasing the production yield, and reduction of effluent discharge and solid wastes

generation. This can be accomplished through waste minimization and process control.

5.1 Waste minimization

Waste minimization is the:

1. Reduction in the generation of waste.

2. Reuse of waste materials/by-products.

3. Recycling of waste materials.

Pollutant Type Efficiency

Gaseous SO2, NO2, HC 30 - 60%

PM PM10 90 - 99%

13

The driving force for waste minimization for industry is improved yields of product, reduced

effects on the environment and lower wastewater treatment costs. Best practice management

options for waste in decreasing order of preference are given as following:

Strategies for minimizing waste in a dairy plant are suggested in Table 5.1:

Table 5.1 Waste minimization strategies

Plant · Planning area and layout for works

Processes · Prevent spillages and purge lines

· Automate CIP systems

· Maintenance of equipment

· Recover and recycling of waste (membrane technology)

· Monitor processes (alarms, interlocks)

· New technology

Personnel · Waste management program and training

· Staff training

5.2 Process control

Sources of waste

Dairy configuration and the products may affect the nature and concentration of dairy wastes.

The amount of product lost depends on design and operational factors including:

- The range of process technologies in use

- The availability of adequate process monitoring, and plant and procedure

alarms/interlocks

- The availability of automated operation – especially automated Clean-In-Place (CIP)

systems and procedures

- The level of management and operator commitment, training and efficiency

- The level of routine equipment maintenance

Most site losses come from activities associated with liquid handling and, to a lesser extent,

with the discharge of air and solid waste. Some examples of avoidable losses are:

- Leaking valves, pumps, pipelines or other fittings – the volume lost may not be large

but the pollution load may be great

Avoid Reduce Reuse & Recycle

Treatment Disposal

14

- Spills from overflows, malfunctions and poor handling procedures – spills usually

happen over a short period but the amount and the high concentration of milk or

product lost may be a significant increase in the pollution load

- Losses from processing and cleaning during the normal operation of plant and

equipment – this includes the deliberate discharge of unwanted materials such as whey,

spent cleaners and diluted product not thought to be worth recovering

Suggested measures for reducing waste

Liquid milk production may lead to the generation of odor, wastewater, noise and solid waste.

Best practice involves processing the predominant by-products such as whey, buttermilk into

high value products like, buttermilk powder (BMP), whey powder, whey protein concentrate

and casein, rather than being used as low value animal feed/fertilizer or being dumped as

waste.

The techniques listed below in Table 5.2 is based on the following techniques for

implementing cleaner production

1) Improved housekeeping practices

2) Process optimization

3) Raw material substitution

4) New technology

5) New product design

15

Table 5.2 Cleaner Production Assessment and Techniques in Liquid milk production

Process Inputs and Outputs Description Environmental Issue Cleaner

Production Focus Techniques

Receipt

and

storage of

milk

- Raw milk is received at processing plants in milk tanker

- At the central collection facilities, mik is measured its quality and fat

content.

- The milk is filtered and/or clarified by cenfigures to remove

dirty particles as well as udder

and blood cells

- The milk then is cooled and storaged in insulated vessels until

required for production

- Empty tanks are washed for the next batch.

- High organic load to the effluent stream

- Associated downstream

problems

- Reducing the amount of milk

lost to effluent

stream

- Reducing amount of water used for

cleansing

- Avoiding milk spillage when disconnecting pipes and hose

- Equipped tank with level

control to prevent overflow

- Using clean-in-place systems

for internal cleansing of

tankers and milk storage

vessels

- Improving cleansing regimes and training staff

- Reuse final rinse water for initial rinses in the CIP

operation

Separation

and

standardiz

ation

- Milk is separated to remove fat

from raw milk (e.g. milk with

cream contain 40% fat whereas

skimmed milk has only 0.5% fat)

- Standarization is process to ensure that the milk product has

consistent composition.

Standardaztion is achieved by

remixing cream with skimmed

milk

- High organic load of effluent stream

- Wastewater contain

milk solid and

cleaning agents

- Reducing the generation of

separator sludge

- Optimizing its collection and

disposal

- Reducing the frequency with which the centrifugal

separators cleaned by

improving milk filtration at the

receiving stage or clarification

of raw milk

- Collecting sludge and disposing of it along with

other solid waste

16

Pasteuriza

tion and

homogeni

zation

- Pasteurizartion is process that milk is heated up to 65

oC for

bacth process and 78oC for

continuous pasteurization process

for at least 15seconds. Then, the

milk is cooled to below 10oC

immediatedly after heating.

- Homogenization is process to break up the butterfat globules to

a size that keep it in suspension.

- High level of energy consumed for the

heating and cooling

of milk

- Wastewater contain

milk solid and

cleaning agents

- Increasing the losses of milk and organic

load into effluent in

batch process

- Improving energy

efficiency

- By changing heat

exchange for

better heat

transfer

- Replacing batch pasteurizers with continuous process

incorporating plate heat

exchanger (PHE) pasteurizers.

- Install new manufacturing equipment

- Avoiding stops in continuous processes

- Reducing the frequency of cleaning of pasteurizers

Deodoriza

tion

The odor substances are drawn-off

by injectecting steam into the

system under vacuum. If the odor is

only mild, a vacuum alone may be

used.

Large volume of water

used to operate water

seals on the vacuum

pump

Reducing the use

of water

Re-circulate the water used in

vacuum pump to reduce or

eliminate the necessity of

discharge it

Storage

and

packaging

- Milk is bottled and/or packaged in

a number of types of containers,

including glass, plastic, paper

carton, etc. Normally, filling of

containers is highly automated.

- After filling, the packaged milk products are usually packaged and

transported in wire and or plastic

crates.

- Loss of milk products from spills

and packaging

mistakes

- Generation of wastewater from

cleaning process

- Carton creates solid waste during the

process of

packaging.

Preheating the

heating plate of

packaging machine

- Make continuous process

- Using high grade carton so it not break

17

6. Case study Meiji dairy industry

6.1 Waste segregation

Three type of waste results from the dairy industry which are liquid waste (Leaked milk, waste

water, and refrigerant loss), solid waste (Clarification solid, spent filter, packaging materials,

and rejected packaging) and gas (Condensate, odor, air emissions like VOC). However the

waste type in milk industry is liquid in nature. The nature of the waste water (acidic or

alkaline) mainly depends on the cleaning process which utilizes both acid and base for

cleaning in different batch. (Please refer to appendix F for detailed description of the waste)

In CIP process, alkali and acidic solvents are used to clean the tank in the dairy production

process before a new batch operation, the concept of solvent reuse is applied in this step to

recover ~80% of the solvents back to the CIP process.

6.2 Waste sampling and monitoring

6.2.1 Monitoring of emissions to air

Table 6.1 Monitoring plan of air pollution

SN Unit Parameter Method Frequency

1 Boiler Stack Emission SO2, NOx, CO, PM10 Manufacturing Instruction Annual

2 Boiler Combustion Efficiency Manufacturing instruction Annual

3 Drier, filter PM10 Isokinetic sampling Annual

4 Conditioning Unit PM10 Isokinetic sampling Annual

5 Factory Odor Olfactory (sniff) assessment Daily

Figure 6.1 Solvent recovery in CIP process

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6.2.2 Monitoring of aqueous emissions

Table 6.2 Monitoring plan of wastewater

SN Monitoring Point Parameter Method Frequency

1 Before Screening Flow Parshall flow meter Real time

2 Before Equalization BOD Azide modification method 1 time/week

pH pH meter Real time

TSS Gravimetric method 1 time/week

TKN Micro Kjedahl method 1 time/week

TP Ascobic method 1 time/week

Temperature Thermometer Real time

3 Activated Sludge COD Automatic Sampler Real time

4 Effluent BOD Azide modification method 1 time/week

pH pH meter Real time

TSS Gravimetric method 1 time/week

TKN Micro Kjedahl method 1 time/week

Temp Thermometer Real time

6.2.3 Monitoring of solid waste

The recording in a register types, quantities, date and manner of disposal/recovery of

all wastes.

Leachate testing of sludge and other material as appropriate being sent for landfill.

Annual waste minimization report showing efforts made to reduce specific

consumption together with material balance and fate of all waste materials.

6.3 Waste treatment plant layouts

Waste generated in CP-Meiji Company Limited is divided into solid waste and effluent from

production process and office waste. For waste coming from production process i.e. solid

waste and effluent discharge are treated on-site of the factory whereas almost office waste

(organic and inorganic waste) that has characteristic of domestic waste is disposed to the

municipal collection system.

Solid waste management in the CP-Meiji plant comprises of different disposal and recycling

systems. Solid wastes from production process i.e. damaged package (glasses, paperboard,

plastic containers, etc.) and from non-production process i.e. food waste from canteen,

rubbish, scrap metals and office wastes will be disposed to municipal collection system. Boiler

ash and sludge from wastewater treatment will be disposed to a landfill. Finally waste from

paper packaging materials will be sold to recycling shops.

For wastewater treatment, this dairy industry treats 94 m3/day of wastewater, and the system

was designed to handle high organic loading (BOD ~2,000 mg/L) and suspended solid.

Effluent from milk production (i.e. mainly from cleaning process) is treated in a wastewater

19

treatment plant (Figure 6.2). Firstly, effluent is passed through the screening to remove dirty

particles release from empty tanker of raw milk. Wastewater is then held in an equalization

tank to avoid shock loading and pH adjustment for microorganisms in aeration tank. In the

next stage, the effluent is pumped into the DAF to remove suspended solids and fats, reducing

the organic load of the wastewater. FOG collected from DAF is then sent to landfill. An

activated sludge tank is used to degrade the remaining organic substance in the wastewater.

The treated water is held in a sedimentation tank to remove the sludge prior to discharge to a

wetland and finally to receiving stream. For the sludge from sedimentation tank, one is

returned to aeration tank in order to maintain the amount of microorganisms and the rest is

concentrated in a sludge thickener and dried in a filter press before disposal in a landfill. A

filtrate from filter press is returned to equalization tank to treat again. (Please refer to

Appendix G for WWTP diagram)

Figure 6.2 Wastewater Treatment Plant Layout

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6.4 Typical cost information

Typical capital and operation and maintenance cost of unit operations in the CP-Meiji Dairy

industry wastewater treatment plant.

Table 6.3 Typical cost of milk production process

Items

Total annual

expenditure

(USD)

Unit cost

(cent/liter)

Cost

(Percent)

Raw material 308,948.48 27.02 91.79

Reception of milk 2,392.87 0.21 0.71

Separation 4,785.76 0.42 1.42

Pasteurization/Standardization 2,630.75 0.4 1.34

Packaging 11,964.44 1.05 3.55

Storage 3,988.13 0.35 1.19

Overall 336,599.63 29.45 100

Total quality produced 1,407,398 liters per year

(Source: A Study on the Economics of Milk Processing in a Dairy Plant in Patiala, A.K.

Chauhan, K.K. Kalra)

Table 6.4 Unit operation and construction cost

Unit Operation Capital cost

(USD)

Annual operation and

maintenance cost

(USD)

Screen 99,155.34 323.21

Grit Chamber 182,460.24 52.942.69

Equalization Tank 92,517.03 3,490.72

Dissolve Air Floatation system 535,567.05 32,340.88

Coagulation/Flocculation 425,450.38 13,201.44

Primary Sedimentation 83,712.65 9,909.77

Activated sludge system 304,468.41 15,837.53

Secondary Sedimentation 83,712.65 9,909.77

Sludge Thickener 30,705.41 2,811.97

Filter Press 141,471.15 12,960.92

Wetland 58,178.68 2,747.33

(Source: A Study on the Economics of Milk Processing in a Dairy Plant in Patiala, A.K.

Chauhan, K.K. Kalra)

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6.5 Simple unit process material balance calculation

6.5.1 Mass balance for whole (micro scale) process

Input L/d

Milk 105,000

Water 151,200

Total 256,200

Output L/d

Wastewater 151,200 x 0.8 = 120,960

Skimmed milk = 100,000

Cream [4% x 105,000 – (0.5% x 100,000 +4% x 525] / 40% = 9,198

Milk loss 105,000 x 0.5% = 525

Total 230,683

Efficiency = (Output/Input) x 100

= (230,683 / 256,200) x 100 = 90.04 %

Loss = 100 - Efficiency

= 100 – 90.04 = 9.96 %

Cream 9,198 L/d

Milk 100,000 L/d

Wastewater 120,960 L/d

Milk loss 525 L/d

Fuel consumption (natural gas) 1,202 m3/day

Electricity 5,733kWh/d

Water 151,200 L/d

Raw milk 105,000 L/d

Milk production

Figure 6.3 Mass balance for whole process

Assumption:

Milk contains 4% fat

Milk after separation are skimmed milk (0.5% fat) and cream (40% fat)

Wastewater is generated about 80% of water input

Density of wastewater is 1.0 kg/L

Density of milk = 1.030 kg/L

Milk loss: 0.5%

22

6.5.2 Mass balance for one (micro scale) unit

Input kg/d Raw milk (105,000 L/d x 1.036 kg/L) = 108,780

Water 13,230 L/d x 1.0 = 13,230

Detergents

(NaOH, HNO3)

= 134.93

Total 122,144.93

Output kg/d Wastewater (13,230 kg/d x 80%) = 10,584

Discharged detergents (1 – 0.9) x 134.93 = 13.49

Skimmed milk (100,000 L/d x 1.036 kg/L) = 103,600

Cream (1 – 0.95 – 0.5%) x 108,780 = 5,125.61

Milk sludge 108,780 – 103,600 – 5,125.61 = 54.39

Total 119,364

Separation & Standardization

Cream 5,125.6 kg/d

Skim milk 103,600 kg/d

Milk sludge 54.4 kg/d

Wastewater 10,584 kg/d

Raw milk 108,780 kg/d

Water 13,230 kg/d

Detergent 135 kg/d

Recycled detergents 121 kg/d

Discharged detergents 14 kg/d

Figure 6.4 Mass balance for separator and standardization

We assume:

Wastewater is generated about 80% of water input

Conversion efficiency is 0.95

Density of wastewater is 1.0 kg/L

Density of milk at 4.4 C= 1.036 kg/L

Recycled detergent efficiency is 90%

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Efficiency = (Output / Input) x 100

= (119,364 / 122,144.93) x 100 = 97.72 %

Loss = 100 - Efficiency

= 100 – 97.72 = 2.28 %

6.5.3 Mass balance for a tie compound

Input kg/d Raw milk (105,000 L/d x 1.036 kg/L) = 108,780

Water 13,230 L/d x 1.0 = 13,230

Fat in raw milk 0.4 x 108,780 = 4,895

Total fat input 4,895

Centrifugal separator

Fat in cream4,351 kg/d

Fat in raw milk 4,895 kg/d

Fat in Wastewater 7.5 kg/d

Wastewater 10,584 L/d

(0.07%v/v of Fat)

Fat in skim milk 98 kg/d

Cream

(40% fat)

Skim milk 97,735 kg/d (0.1% Fat)

Raw milk 108,780 kg/d (4% fat)

Figure 6.5 Mass balance for tie compound (fat)

We assume:

Wastewater is generated about 80% of water input

Conversion efficiency is 0.90

Density of fat is 1.0115 kg/L

Density of milk at 4.4 C= 1.036 kg/L

Fat in raw milk: 4%

Fat in cream: 40%

Fat in skimmed milk: 0.1%

Fat in wastewater: 0.07%v/v

24

Output kg/d Wastewater (13,230 kg/d x 80%) = 10,584

FOG in wastewater 10,584 x 0.07% x 1.0115 = 7.494

Cream 108,780 x 0.1 = 10,878

Fat in cream 10,878 x 0.4 = 4351.2

Skimmed milk 108,780 – 10,878 – 7.494 / 4.5% = 97,735.5

Fat in skimmed milk 0.1% x 97,735.5 = 97.735

Total fat output 4,456.4

Efficiency = (Output / Input) x 100

= (4,456 / 4,895) x 100 = 91 %

Loss = 100 - Efficiency

= 100 – 91 = 9 %

25

6.6 Major O & M issues related to wastewater treatment plant

Table 6.6 Major O & M issues related to wastewater treatment plant

Unit Problems Remediation Remarks

Screen

Clogging of pump from solids particles

(large and small glasses, papers,

cardboards, milk solid )

Require coarse and fire screen before DAF -Coarse screen: prevent large particles.

-Fine screen: prevent small particles.

Equalization

Tank

- Overflows during peak storm water

loads

- Solids settling in bottom of equalization

tank

- Separate storm water from wastewater

- Send wastewater to other plant or CETP that

can treat diary wastewater

- Require screens for solid removal

Storm water will be discharged into

river

Dissolved Air

Floatation

(FOG removal)

Clogging of nozzles from suspended

matter

Shift to Cavitations Air Flotation method

Activated sludge

Tank

(BOD removal)

-DO concentration lower than 2-3 mg/L

from no adequate aeration

-Excessive foaming from high aeration to

make sludge settle down in a secondary

sedimentation tank

- Install probe to monitor DO concentration

> 2-3 mg/L

- Change aeration method to diffuse air overall

area of tank

Sedimentation

Tank

- Bulking sludge from a slight weight

sludge of fungi

- Rising sludge from large amounts of

sludge in tank

- Prevent the contamination from air into water

to prevent fungi

- Increase F/M ratio and return activated sludge

pumping rate and reduces sludge blanket depth

- The floc does not settle or compact and

discharge with effluent.

-There are nitrification and denitrification

that nitrogen gas make sludge rise

Sludge

Thickener

Low sludge settling efficiency Ensure adequate stirring with Pickets

Filter press

High energy consumption when sludge

contain low solid content

Use sludge thickener and sludge digester to

increase percentage of solid before sludge

dewatering by filter press

Improvement of more sludge treatment

facilities depend on the amount of

sludge and budget

26

Reference

http://www.fonterra.com/au/en/Financial/Global+Dairy+Industry

Djekic, I., et al. (2014). Environmental life-cycle assessment of various dairy products.

Journal of Cleaner Production.

DLD. (2012). Thailand Dairy Industry.

FAO. (2009). Smallholder dairy development: Lessons learned in Asia.

Krijger, A. (2012). The World Dairy Situation 2012. International Dairy Federation.

Krijger, A. (2013). The World Dairy Situation 2013. International Dairy Federation.