The dairy industry produces large volumes of wastewater from various processing stages like pasteurization, homogenization, and cheese or butter making. Wastewater sources include cleaning operations, product losses, and leaks. Dairy wastewater is characterized by high levels of nutrients, organic matter, and microbes. It may also contain detergents, salts, and other chemicals depending on processing. Treatment methods include primary physical and chemical processes, as well as secondary biological processes like aerobic and anaerobic digestion. Both have advantages and disadvantages for treating lower or higher strength wastewaters.

2. WASTEWATER GENERATION
 The dairy industry is one of the most
polluting of industries, not only in terms of
the volume of effluent generated, but also in
terms of its characteristics as well.
 A chain of operations involving receiving
and storing of raw materials, processing of
raw materials into finished products,
packaging and storing of finished products,
and a group of other ancillary operations
(e.g., heat transfer and cleaning) will
produce wastewater.

3.  In the dairy industry, some amount of
wastewater gets produced during starting,
equilibrating, stopping, and rinsing of the
processing units. However, a majority of
wastewater gets produced during cleaning
operations, especially between product
changes when different types of products are
produced in a specific production unit and
clean-up operations. Dairy processing effluents
are generated in an intermittent way and the
flow rates of these effluents change
significantly. The quality and quantity of the
product content in the dairy wastewater at a
given time changes with the application of
another technological cycle in the processing
line.

4. SOURCES OF WASTEWATER
DAIRY PROCESS SOURCES OF WASTE
Preparation stages
1) Milk receiving/storage.
2) Pasteurization/Ultra heat
treatment
 Poor drainage of tankers
 Spills and leaks from
pipes
 Foaming
 Spils from storage tanks
 Cleaning operations
 Liquid losses
 Foaming
 Recovery of downgraded
product
 Cleaning operations
 Deposits on surface of
heating equipment.

5. 3) Homogenisation
4) Separation/Clarification
Product Processing
Stage
5) Market milk
 Liquid losses/leaks
 Cleaning operations
 Foaming
 Pipe leaks
 Product washing
 Sludge removal from
clarifier
 Damaged milk packages
 Overfilling
 Poor drainage
 Cleaning of filling
machinery
 Leaks
 Cleaning operations

6. 6) Cheese Making
7) Butter Making
8) Milk powder manufacture
 Overfilling vats
 Incomplete separation of
whey from curd
 Using salt in cheese
making
 Product washing
 Vacreation( reduced
pressure pasteurization
using stream) and salt use.
Spills of powder handling
 Start up and shut down
losses
 Plant malfunction
 Stack losses
 Cleaning of evaporators
and driers
 Bagging losses

7. EFFLUENT GENERATION FROM VARIOUS UNITS
OF MILK OPERATION
CLARIFICATION/STANDARDIZATION
STORAGE TANK
RECEIVING
PASTEURIZATION
HOMOGENISATION
DEODORISATION
STORAGE TANK
PACKING
STORAGE
TRANSPORTATION
DS
WW
DS WW
DSWW
DS WW,CW,ST
DS WW
ST, DS WW
DS WW
DS WW
DS WW
EF
EF
EF
EF
EF
EF
EF
EF
EF
EF
DS-Detergents and Sanitizing Agents, WW-Wash Water, ST-Steam, CW-Cooling Water.

8. CHARACTERISTICS OF WASTE WATER
 Dairy wastewater contains milk solids, detergents,
sanitizers, milk wastes, and cleaning water.
 It is characterized by high concentrations of nutrients,
and organic and inorganic contents.
 Salting activities during cheese production may result in
high salinity levels.
 Wastewater may also contain acids, alkali with a number
of active ingredients, and disinfectants, as well as a
significant microbiological load, pathogenic viruses, and
bacteria.
 Other wastewater streams include cooling water from

9. Parameters UNITS GUIDELINE VALUE
pH - 4-12
Suspended solids mg/l 24-5700
BOD5 mg/l 450-4,790
COD mg/l 80 - 95000
Total nitrogen mg/l 15-180
Total phosphorus mg/l 11-160
Oil and grease mg/l 10
Total coliform bacteria Mpn/100ml 400
Magnesium mg/l 25-49
Potassium mg/l 11-160
Chloride mg/l 48-469
Calcium mg/l 57-112
BIS GUIDELINES OF PARAMETERS

10. BOD : COD RATIO
BOD:COD Ratio of Milk Constituents
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Whole
Milk
Skim
Milk
Butter
Milk
Whey
Lactose
Casein
Whey
Protein
Fat
Constituents
BOD:COD

11. TREATMENT METHODS
 Primary:
i. Physical
Treatment
ii. Chemical
Treatment
 Secondary:
i. Biological
Treatment
ii. Chemical
Treatment
iii. Membrane
Method
iv. Electrolytic
Method

12. Primary Treatment

13. Secondary Treatment

14. Aerobic Process of Treatment

15. ANAEROBIC PROCESS OF
TREATMENT
• Conventional Anaerobic Digester
• Anaerobic Contact Digester
• Anaerobic Fixed Film Reactor
• Up flow Anaerobic Sludge Blanket
• Two Phase / Hybrid Reactor
• Combined - Anaerobic & Aerobic
Process

17. Chemical Treatment
• It can reduce COD by 78% and BOD by 84%.
Membrane Method:
• It can reclaim Valuable milk solids or
chemicals for resale, reuse or less expensive
method.
Electrolytic Method
Miscellaneous and Modified Method

18. TERTIARY
TREATMENT(Optional)

19. BIOLOGICAL TREATMENT
Aerobic Anaerobic
Applicability low strength: low, medium and high strength:
(BOD, mg/l) (100 - 2000 mg/l) (250 - > 100.000 mg/l)
BOD-removal: 93-99% 90%
NH3-conversion: 95% low
NO3-removal: 90%* high

20. Advantage Disadvantage
Anaer
obic
* possible production of energy
* low need for land
* power failure or shutdown will not
affect the system
* no energy consumption
* low production of excess sludge
* optimal process temperature is about 30°C
* post-treatment for BOD-removal is often
required
Aerob
ic
* low process temperature
* end treatment of waste-water
* energy need for aeration
* high need for land
* power failure or shutdown will affect the
entire system
* post-treatment for further nutrient removal is
often required
* high production of excess sludge