Dairy effluent contains dissolved sugars, proteins, fats, and minerals from dairy processing. It has a high biological and chemical oxygen demand. Common treatment techniques include screens and separators to remove floatable solids, and equalization tanks to reduce flow fluctuations. Primary treatment uses sedimentation to remove settleable solids. Secondary treatment uses biological oxidation in aerobic ponds, facultative ponds, or activated sludge processes to reduce organic content by 70-90%. Anaerobic digestion further breaks down material to produce biogas. The overall goal is to reduce pollutants before environmental discharge or reuse.

1. College of Veterinary and Animal Science,
Navania, Vallabhnagar,Udaipur
Dairy Effluent Treatment
Submitted by
Jayesh Dhoral

2.  Demand of milk and milk products is increasing day to day.
 Dairies collect milk from farmers and either bottle it or manufacturer various
milk products.
 During these processing large quantity of effluent is generated.
 Spills and leaks of products or by products, residual milk or milk products in
piping and equipment before cleaning,wash solutions from equipment and
floors , condensate from evaporation processes,cheese trimming are some of
the sources of dairy effluent in a dairy plants.
INTRODUCTION

4. Dairy effluent:-
 Dairy effluents contain dissolved sugar, protein, fat and
minerals.
 The key parameters of dairy effluent are biological
oxygen demand(BOD), chemical oxygen
demand(COD),total suspended solids, total dissolved
solids etc.
 Common dairy waste techniques:- Grease traps, oil
water separators for separation of floatable
solids,equilization tanks.
 B.O.D.:-is a important measure of water quality and is
the amount of dissolved oxygen cosumed by bacteria
and other micro- organisms to oxidised the organiuc
matter in waste water over a period of 5 days at 20
degree celcius.
 C.O.D.:-is the amount of oxygen necessary to oxidise

6. Objectives :-
 To reduce the organic content of the waste water.
 To remove or reduce nutrients that could cause pollution of
receiving surface waters or ground water.
 To remove or inactive potential pathogenic micro-organisms
or parasites.

7. PROCEDURE

8. PRE- TREATMENT
Includes flow equilization and the separation of floatable
matter and settleable solids.
(1)Flow equilization
Flow equilization is adopt to reduce hydraulic loading in the waste
stream.
Consists of a holding tank and pumpimg device to reduce the
fluctuation of effluent discharge.
The equilisation tank has the capacity to store waste water for
recycling and reuse through out the day.
(2)Screening
Most frequently used process.
Screening devices:- Vibrating screens, static screens, or rotary
screens.
The screening device hold the solids and are remove from screen.

10. Screening

11. (3)Skimming
 Skimming is frequently incorporated if large
floatable solids are present.
These solids are collected and transferred into
some disposal unit.

12. PRIMARY TREATMENT
Principle – To remove particles from the
waste water.
(1)Sedimentation
 Most common primary treatment technique used to remove
solids from the waste water in effluent because most waste
water contains substantial amount or readily settleable
solids.
 About 40 – 60% solids or about 25-30 % of the BOD can be
removed by screening and sedimentation.
 A rectangular settling tank or circular tank clarifier is most
frequently used for the sedimentation process.
 In this process, Sludge settle down on the bottom

13. Floatation
 This is a treatment process in which oil, grease and their
suspended solids are removed from waste water.
 Air bubbles can be created in the waste water treatment
process by using rotating impellers or air diffusers to form
air bubbles at atmospheric pressure.
 Tiny particles get attached to air bubbles and the specific
gravity of the aggregate particles become less and thus
get separated on the top.

14. SECONDARY TREATMENT
Treatment through biological oxidation is the most
common technique for secondary treatment.
(a)Aerobic ponds
 Aerobic and anaerobic ponds have normally been referred to as
stabilization ponds.
Approaximately 20% of BOD sent to an aerobic ponds is converted
to sludge, solids and BOD is reduced by 70 – 90 %.
These ponds incorporated use of mechanical aerators to supply
atmospheric oxygen for enhancing biological oxidation.

15. Aerobic lagoons

16. (b)Facultative ponds
 Treatment is achieved by action of aerobic, aerobic and
facultative micro-organisms.
 In the upper zone, oxygen is supplied by photosynthetic
green and blue green algae.
 In aerobic zone, heterotrophic bacteria degrade organic
matter in dairy wastes and produce carbon di oxide and
micro- nutrients needed by algae . Dead bacteria and
algae settle to the bottom of the pond and are degraded
by anaerobic micro-organisms.
 During anaerobic decomposition, methane, hydrogen
sulphide, carbon dioxide and nitrogen may be released to
the atmosphere. Sludge removed from the base of pond.
BOD removals of upto 90% .

17. (c) Anaerobic ponds
 The treatment principle involved with this method involves biological
oxidation and solid sedimentation
 This treatment involves conversion of dissolved, suspended, and settled solids
to volatile gases such as oxygen, carbon dioxide, nitrogen, and methane.
 Under anaerobic conditions, anaerobes digest the organic matter.
 BOD reduction efficiency = 60-80 %

18. Activated sludge process for waste
treatment
 The activated sludge process involves return of a portion
of the clarifier- settled sludge to be mixed with waste
water entering the reactor.
 The process consists aerobic oxidation of organic matter
to carbon dioxide, ammonia, water and cell biomass
followed by sedimentation of activated sludge.

20. SKIMMING

21. TRICKLING FILTER

22. Anaerobic Digestion
 Anaerobic digestion is a process by which micro-
organisms breakdown biodegradable material in the
absence of oxygen.
 In anaerobic digestion of dairy waste water, acidogenic
bacteria convert the sugar and amino acids into carbon
dioxide, nitrogen, ammonia and organic acids. It serves as
excellent manure when dried.

24. Thank you !