Industrial Waste Management-Verka Milk Plant

INDUSTRIAL WASTE MANAGEMENT

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HARKRISHAN SINGH M.TECH (ENVIRONMENTAL SCIENCE & TECHNOLOGY)

601101008

MILKFED-VERKA The Punjab State Cooperative Milk Producers’

Federation Limited

Patiala, Punjab

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ABOUT THE INDUSTRY The Punjab State Cooperative Milk Producers’ Federation Limited popularly known as MILKFED Punjab, came into existence in 1973 with a twin objective of providing remunerative milk market to the Milk Producers in the State by value addition and marketing of produce on one hand and to provide technical inputs to the milk producers for enhancement of milk production on the other hand.

Although the federation was registered much earlier, but it came to real self in the year 1983 when all the milk plants of the erstwhile Punjab Dairy Development Corporation Limited were handed over to Cooperative sector and the entire State was covered under Operation Flood to give the farmers a better deal and produce better products for its customers.

The industry is today ISO 9001 : 2008 certified while being the first in Punjab to be ISO 22000 certified with GMP (Good Manufacturing Practices), GCP (Good Clinical Practices) and GLP (Good Laboratory Practices) certification from Food Safety and Standards Authority, India.

PRODUCTS

• Processed Cheese • Cheese Spread • Sweetened flavored milk • Paneer • Dahi • Kheer • Lassi • Packaged Milk • Cream (for catering purpose only) • Khoya (for catering purpose only)

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PRODUCT DESCRIPTION

• Processed Cheese: Milk fermented product with a shelf life of 6 months available in packaging of 500gm, 250gm and 100gm.

• Cheese Spread: Milk fermented product available in the form of paste with a shelf life of 6 months. Available in packaging of 500gm and 250 gm.

• Sweetened Milk: Marketed under the brand name of ‘Pio’ is flavored milk available in Elaichi, Butterscotch, Strawberry, Pista and Coffee flavor in 125mL bottles.

• Paneer: Coagulated Milk Proteins available in 200gm packaging with a shelf life of 10 days. • Dahi: Milk fermented product available in 200gm and 400gm cups and 20kg cans with a shelf life of 10

days. • Kheer: Sweetened milk and rice product available in 200gm packing with a shelf life of 2 weeks. • Lassi: Milk fermented product available as Plain & Sweet flavored in 200ml, 500ml and 1L packing

with a shelf life of 2 weeks. • Packaged Milk: Milk available in 500ml packing as Skimmed Milk (0% fat), Double Toned Milk

(1.5% fat), Toned Milk (3.0% fat), Standard Milk (4.5% fat) and Full Cream Milk (6.0% fat) with a shelf life of 2 days.

CORE ACTIVITIES

• Milk procurement • Filteration • Cream Seperation • Pasteurization • Homogenization • Storage • Fat Percentage and SNF (solid-not-fat) ratio adjustment • Milk Supply to Different Sections of Production • Paneer, Kheer, Dahi, Lassi, Cheese, Packaged Milk & Flavored Milk Production

• In-Bottle Sterilization

SUPPORT ACTIVITIES

• Washing of Bottles, Milk Cans and Trays

• Chilled water plant & circulating chilled water system

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• Boiler & Steam distribution system • Packaging • Storage of Processed Products • Quality Testing Lab • Storage for Chemicals (citric acid, micro-organism culture) • In-house Fuel Filling Station • Housing Colony • Convenience Facilities • Transport Vehicle Garage and Repair Centre • Office Space and facilities • DG sets (2 of 250KVA each) and Transformer

PROCESS STEPS

• The milk is procured from 69 Milk Chilling plants installed in different villages in trucks with chilling units installed or from local dairy farms in 80lb containers.

• The milk procured in containers is transferred to collection room via chain driven conveyor belt where the milk is filtered through cloth and put into centrifugal cream separator along with milk procured from tankers.

• The separated cream is packed in containers and sold separately or used to adjust fat and SNF ratio. • The milk is then sent to the pasteurization unit where HTST-Pasteurization is done at 78oC for 15 sec

and then cooled to 1.5oC. • The Pasteurization unit has a temperature sensor installed. If the temperature of the pasteurized milk is

not within the range of 74oC-78oC then the unit stops the feed and recirculates the output milk. • After Pasteurization, to break the fat globules Homogenization is done in two steps by passing

compressed air at 2000 psi and 800 psi respectively. • Steam from boiler and cooling water from chilling water unit is used. Heat exchangers are used for

heating and cooling. • Part of steam condensate is used in tray washing rest is drained out. • The milk is then sent to 11 storage tanks of 15,000L each maintained below 4oC with provision for

mixing. • Fat and SNF ratio of milk is adjusted in these tanks. • The tanks have pipe connections with direction valves to direct the feed to different production sections.

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Paneer & Kheer Section

• Two Storage Tanks of 2000L capacity each are use to store milk. It is heated to 80oC by Heat Exchanger via steam from boiler.

• The milk is taken in a 100L container and 1% citric acid is added to it. • The coagulated proteins are collected and put in a dye mold box. The dye mold boxes put under a press,

which drain out the excess whey retained. The whey from the press as well as the container are put in the drain pipe.

• The solid mass obtained is put in chilled water tub of 500L maintained below 5oC for about half an hour. • The solid mass is then weighed and cut into 200gm pieces and put in packets and are sealed by packing

machine at 75oC. • Kheer is prepared in a steam vessel. 100kg milk with 2kg rice and 30kg sugar is taken in the steam

vessel and cooked till the desired thickness is reached. • Manual packing is done in 200gm cups and sealed by sealing machine. • Boiler provides the steam and the steam condensate is drained out. • The chilling unit provides chilled water. • The temperature of the room is maintained by circulating cooling water and blower system.

Dahi Section

• Feed is taken in an overhead cylinder and seed of microbial culture is added. • It is then filled into cups by automatic machines and sealed. • The cups are then incubated in an Incubation room maintained at 37oC-38oC for 2 hours after which it is

stored in a room maintained below 2oC. • The temperature of the room is maintained by circulating cooling water and blower system.

Flavored Milk Section

• The bottles are washed with sterilizing agents then they are checked against white and black background respectively.

• Flavored Milk is prepared in 2000L cylinders and is filled in bottles via automatic and manual machine. • The bottles are then capped manually and taken for in-bottle sterilization. • The temperature of the room is maintained by circulating cooling water and blower system. • The bottles are placed in trays and the trays are stacked in 6 horizontal steam cylinders (autoclave type

machines) and are sterilized at 121oC, 15psi pressure with steam for 25 min. • The bottles are then cooled to room temperature and taken for branding.

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• The bottles are covered by printed plastic sheets and placed in packing machine maintained at 75oC. The plastic sheet clings to the bottle.

• The bottles are then put in cartons.

Lassi Section

• Milk is fed to an overhead tank where microbial seed is added. • The milk is then taken to a tub of 200L capacity and mixed via mechanical means. • It is then packaged by an automatic packaging unit under vacuum in plastic bags. • The temperature of the room is maintained by circulating cooling water and blower system.

Storage Section

• The storage unit is used to store the products at reduced temperature to increase the shelf life. • The temperature of the room is maintained blow 4oC by circulating cooling water and blower system. • Storage room has a provision for transferring the product directly to truck loading section.

Boiler Section

• Boiler is used to fulfill the needs of steam required in pasteurization and other sections where there is need to raise the temperature of the milk.

• Two Fire Tube boiler of 2TPH (Tons per hour) capacity are installed to supply steam at a working pressure of 15lbs.

• The boiler uses wood as the source of fuel. • Soft water is used, produced by an ion exchanger regenerated by common salt solution (NaCl). • Boiler blowdown is done 2 times a day. • Stack of 20m in height is installed to discharge the flue gases.

Chilling Water Section

• Chilled water is of 60Ton capacity and used for circulating cooling water system to maintain temperature and in Pasteurization unit to lower the temperature.

• The chilling water system is ammonia gas based system and brine water is used. • Condensers are used to condense ammonia gas back to liquid form and lower its temperature.

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PROCESS FLOW DIAGRAM

Pasteurization & Homogenization

Milk%in%%80lb%cans!

Suspended%Solids!

Conveyor%Belt!

Milk%from%Tankers!

Milk%%Collec<on!

Filtra<on!

Centrifugal%Cream%Separator!

H.E!

Cooling%Water!

Cooling%Water!

Pasteuriza<on!

Temperature%based%Sensor!

Cooling%Water!Cooling%Water!

Feed%Lines!

Fat%&%SNF!

Storage!Tank!

Pump!

2000!psi!

800!psi!

Compressed%Air!

Homogenizer!

Cream!

Pump!

Paneer%&%

Kheer%

Dahi! Flavored%Milk!

Lassi% Packaged%Milk%

H.E!

Steam%Condensate!

Steam!

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Paneer & Kheer Section

Dahi Section

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Flavored Milk Section

Lassi Section

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Packaged Milk Section

Boiler Section

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Circulating Chilled Water System

EFFLUENT TREATMENT PLANT

• The wastewater from the plant and the housing colony is collected in two equalization tanks (10ft X 6ft X 8ft)

• It is then transferred to aerated lagoon (14ft X 28ft) • The wastewater is then transferred to Sludge Settling Tank (14ft X 5ft) from where the sludge can be

recycled to maintain MLSS concentration • From where the sludge is pumped and transferred to two sludge drying beds (15ft X 15ft) • The treated water is used for irrigation of green belt within the industry premises.

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Effluent Treatment Plant

ENVIRONMENTAL CONCERNS

• The chain driven conveyor belt system requires frequent oiling and greasing. • The filtered out substances from milk is discarded which are mainly suspended solids and have high

BOD. • The steam condensate from pasteurization and Paneer & Kheer is drained out. Only part of is reused. • The whey from Paneer section is drained out which is high in BOD. • Chilled water used for Paneer dipping is also drained. • Washing of bottles generate huge amounts of wastewater and spillings. It contains chemicals. • Spilling of milk caused while filling the bottles. • Waste heat generated during in-bottle sterilization. • Electrical Input for Sterilizers. • Flue gases emitted from boiler stack. • Boiler blowdown contains high TDS. • Resin needs to be regenerated and replaced in ion-exchanger soft water plant.

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• Resin Backwash water. • Salt solution used for regeneration. • Flue gas discharge. • Fly ash from the boiler. • Burnt fuel ash. • Ammonia gas based chilling unit is used. • Waste heat is generated. • Sludge needs to be disposed off. • Rejected products are sometimes not reusable.

SUGGESTIONS FOR WASTE MINIMIZATION, RECYCLING & REUSE

• Steam condensate can be reused. • Industry can incorporate co-generation • Counter-current washing of trays. • APCD for flue gases from the boiler.