BAKERY  WASTE  WATER  TREATMENT


















Bakery all across world have to have some or the other type of  treatment  plant  for  treating waste water
coming out of the plant . With municipalities  putting up stringent  penalities for violation  of  discharge
water  standards  and pressure to conserve  water  bakeries  are putting waste water treatment plant to
meet these requirement .

Bakery  waste  water are generated  through  machine cleaning , utensil  cleaning  ,floor washing , crate
washing  , spillages in unit , cip of pipelines and dusting done in the plant .

Major raw material  are  flour , fat  , sugar , invert syrup , milk , biscuit , bread crumbs  and other
chemicals  which  gets mixed in water at plant during process


Bakery waste  water have bio degradable  waste  component in it  which  can be treated through  various
chemicals and biological agent .

The important  factors to be monitored   with permissible limits  .

pH-- 6- 10

BOD  ( Biological oxygen  demand   ) - less than 1000mg

COD  ( Chemical Oxygen demand )-less than 3000mg

Oil n Grease- 100mg

Heavy metal- different   for  various heavy metals
( cd , mg , ar cu ,ni) < 1mg
TDS ( Total dissolved  solid )--- 2000mg

TSS ( Total suspended particles )--1500mg

These  limit  varies  from   country  to   country

Different  kind    of     bakery waste  water treatment    are following

1.By nature of treatment

Physical : Waste water  are allowed to passed through several  storage tank.
Chemical: Chemical  are used to treat   the  waste water
Biological:  Biological agents are  used to  treat  waste  water


2. By  aeration

Aerobic -  Air  is mixed  with the  waste water  through blower  for aeration depending upon the volume
Anaerobic - Air  is  avoided and the water is maintained in closed tank  and anaerobic ( bio culture )
reaction takes place . Methane gas is generated in such reaction which can be used for heating
application .

3.Activated  sludge type

Sludge generated due to bacterial action is retained to generate sludge is called activated sludge type  
treatment .



Basic Component of  bakery waste water treatment .

Collection pit
: These pits  are connected to plant where all waste  water are collected it could be at
different locations or a big tank  at one place

Oil  and Grease trap : Oil and grease traps  seperates  the fat and oil content from bakery  waste water .
It uses gravity  concept for seperation of oil & fat .Fat floats on the surface and is taken out manually
through different tools.


Equalisation  tank : Its  a settling  tank which  allows different stream of waste water mix properly prior to
treatment . pH correction is done in this  tank .Soda flakes  are added to increase  the alkalinity of the
water . Quantity  depends upon the volume of the water .Dosing pumps  are used for automated
discharge of quantity into the waste water.

Aeration  tank : Here this waste water is  mixed with air through aerators   submerged either in the
surface or placed in the bottom .Air is generated through blowers and has  enough pressure  to come
out  from membranes attached in aerators .  These tanks  are  some times packed with bio culture  which
enhances sludge formation  and are called  bio reactors . Many types  of bio culture are available  for  
waste water  treatment eg  packed bed , moving media ,fibrous bed  and membrane .

Some times  for better performance anaerobic tanks  are  placed  before  these aeration tank  which
improves the quality  of  the waste water . Its has been observed that  60-70% reduction in BOD at
anaerobic  tanks with retention time upto  1- 4 days .  Anaerobic reactors  have submerged media on
which these microorganism lives and digest these bio degradable  material .


Clarifier : These are settling tank  where sludge  are allowed to  settle down and clear treated water  are
discharged either  to main treatment plant which is further treated and discharge into river / sea  or
recycled and used for gardening or agricultural use.

Sludge  Drying bed  : The sludge settled in  these  tanks are then pumped through pumps on sludge  
drying bed . Beds  could be four to six in numbers so
that they can be used alternatively as   sludge drying takes  some times. These sludge  are then
disposed out  municipality approved sites .


Filter Units : Sometimes activated carbon filters  are attached after clarifiers to clear waste  water from
suspended solids and foriegn particles . Floccullants are added in water prior to clarifier  to further
improve the  quality of water these floccullants reacts with waste chemically and creates  sludge. These
are cations and anions which attracts opposite  particles and makes coagulants which settles down .

The bakery waste water  have bio - degradable  waste hence aeration method are successful for  water
treatment which


Bakery  waste water treatment   Plants  must be kept  at a distance from the factory or the building .
Plant tanks and settling tanks are designed  in respect  to Volume , retention time required , BOD &COD  
reduction  etc .

Package type plants have  been developed   for  optimising space for bakery  units .











Maintenance tips :

  • Clear  and clean all the tank regularly  as any retention  of sludge or water can deteriote the
    quality  of water .
  • Keep a log book for pH correction . Keep Digital pH  for records
  • Maintain  the pumps and blower at treatment plant . Keep spare unit  for  blower and pumps.
  • Keep Adequate amount of  chemical required at plant .
  • Maintain  the  aerators
  • Release sludge to drying  bed regularly
  • Send samples for third party inspection in some intervals .
  • Maintain  temperatures of these tank  in extreme  weather condition .

Some important terms

BACTERIAL COUNT : Health   of aeration tank which  uses these bi cultures  can be checked through
bacterial count .

MLSS: Mixed liquor suspended solid

O/N : Oxygen by Nitrogen ratio

RETENTION PERIOD : Depending upon  the volume , cod , bod and other characteristic plant is
designed in a way that it takes  1- 4 Days for complete travel of water  from inlet to outlet water at
treatment plant .

Chemicals  required  for  bakery waste water  treatment plant

Soda flakes

Iron chloride

Hydrogen peroxide

flocullants

Flow  Diagram for  Bakery Effluent Treatmant  Plant











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BAKERY WASTE WATER , BAKERY WASTE WATER  TREATMENT
bakery waste water , etp , effluent treatment plant , waste water treatment
BAKERY WASTE WATER TREATMENT, BAKERY WASTE WATER
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