The dairy industry generates large quantities of wastewater from various processing plants. Sources of wastewater include bottling, cheese making, butter, condensed milk, ghee, milk powder, and ice cream plants. Dairy waste is biodegradable but strong in nature. It has high levels of BOD, COD, total solids, oil and grease. Treatment alternatives for dairy waste include use for irrigation after primary treatment, low-cost treatment using screens and stabilization ponds, and advanced secondary treatment using activated sludge process.

1. L-25
Dairy Industry
Industrial Waste Treatment

2. Introduction
• Demand of milk and milk products is
increasing day by day.
• Dairies collect milk from farmers and
either they bottle it or manufacture various
milk products.milk products.
• During these processes large quantity of
wastewater is generated.
• Dairy waste though biodegradable but
very strong in nature.

3. The dairy industry is divided into two main
production areas:
1. The primary production of milk on farms-the
keeping of cows (and other animals such as
goats, sheep etc.) for the production of milkgoats, sheep etc.) for the production of milk
for human consumption;
2. The processing of milk with the objective of
extending its saleable life. This objective is
typically achieved by:

4. (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 forma semi-dehydrated or dehydrated form
(butter, hard cheese, ghee and milk
powders), which can be stored.

5. Sources of wastes
• The liquid waste from a large dairy originates
from following sections :-
1. Bottling plant
2. Cheese plant
3. Butter plant3. Butter plant
4. Condensed milk plant
5. Ghee making plant
6. Milk powder plant and
7. Ice cream plant
8. Cleaning and washing of reactors

6. Washing
of Cans
waste
Bottling
plant

7. Whey Powder
making in
Cheese
making
plant
making in
evaporator

8. Pasteurization
Ripening
Cream
Bacteria Culture
Selected
Acid (L.A.)
ButterChurning
Butter Granules
Packing
Buttermilk
To Users
Butter
making
plant

9. Dry milk powder plant
Evaporation
Skimmed milk
Drying
Powder packaging
To users

10. Ice Cream plant
Mixing
Water, cream, butter, milk and whey powders
HomogenizationHomogenization
Pasteurization
Ageing
Flavours, colours
and fruits
Freezing Packing

12. COD and BOD of milk products

13. Composition of wastewater
of typical dairy
Item Value
pH 7.2 (6.5 to 8)
Alkalinity 600 mg/lit as CaCO3
TDS 1060 mg/lit (1200 to 1800)
SS 760 mg/lit (600 to 900)SS 760 mg/lit (600 to 900)
BOD 1240 mg/lit
COD 1840 mg/lit
Total nitrogen 84 mg/lit
Phosphorus 11.7 mg/lit
Oil and Grease 290 mg/lit (250 to 350)
Chlorides 105 mg/lit

14. Treatment alternatives

15. 1. To be used for irrigation after primary
treatment
Screens
Oil and
grease trap
Dairy
waste
For
irrigationwaste irrigation

16. 2. Low cost Treatment
Screen
chamber
Stabilization
pond
O and G
trap
Dairy
waste Effluent

17. 3. ASP
Secondary
SST

20. Objective Questions
1. pH of dairy waste is in the range of
____________.
2. ____________ trap is needed for
treatment of dairy waste.
3. Oil and grease present in the dairy waste
is in the range of ___________.

21. Theory questions
Q1. W r t dairy industry draw manufacturing flow
sheets of
i. Milk receiving and Bottling plant
ii. Cheese making plant
iii.Butter manufacturing plant
iv.Ice cream plantiv.Ice cream plant
v. Dry milk powder plant
Q2. Draw Process flow sheet of a dairy and clearly
mention sources of wastewater generation.
Q3. Give general characteristics of dairy waste.
Q4. Discuss various treatment alternatives for dairy
waste with the help of neat flow diagrams