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