Date post: | 16-Jul-2015 |
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Engineering |
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L-25Dairy Industry
Industrial Waste Treatment
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.
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 milk goats, 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:
(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 a semi-dehydrated or dehydrated form (butter, hard cheese, ghee and milk powders), which can be stored.
Sources of wastes
• The liquid waste from a large dairy originates from following sections :-
1. Bottling plant2. Cheese plant3. Butter plant3. Butter plant4. Condensed milk plant5. Ghee making plant6. Milk powder plant and 7. Ice cream plant8. Cleaning and washing of reactors
Washing of Cans
waste
Bottling plant
Whey Powder making in
Cheese making plant
making in evaporator
Pasteurization
Ripening
Cream
Bacteria CultureSelected Acid (L.A.)
Butter Churning
Butter Granules
Packing
Buttermilk
To Users
Butter making plant
Dry milk powder plant
Evaporation
Skimmed milk
Drying
Powder packaging
To users
Ice Cream plant
Mixing
Water, cream, butter, milk and whey powders
HomogenizationHomogenization
Pasteurization
Ageing
Flavours, colours and fruits
Freezing Packing
COD and BOD of milk products
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
Treatment alternatives
1. To be used for irrigation after primary treatment
Screens Oil and grease trap
Dairy waste
For irrigationwaste irrigation
2. Low cost Treatment
Screen chamber
Stabilization pond
O and G trap
Dairy waste Effluent
3. ASP
Secondary
SST
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 ___________.
Theory questionsQ1. W r t dairy industry draw manufacturing flow
sheets of i. Milk receiving and Bottling plantii. Cheese making plantiii.Butter manufacturing plantiv.Ice cream plantiv.Ice cream plantv. Dry milk powder plantQ2. 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