The cleaning is collectively passed through the screen chamber

The wastewater generated from the plant is collectively
passed through the Bar screen chamber to remove the floating matter present in
the wastewater, oil and grease are removed in oil and grease chamber. The
quality and quantity of the wastewater is maintained in the equilization tank where
coarse diffusers of size 90mm dia and 800mm long are provided for the supply of
oxygen. The wastewater is then allowed to the aeration tank where the tank is
provided with fine diffusers of size 90mm dia and 1000mm long. The tank is
seeded with DAP and oxidation of organic matter is done with the help of
micro-organisms and here BOD and COD reduction takes place to a significant
level. The treated wastewater is sent to secondary clarifier, here a small
amount of BOD and COD can be seen. Portion of secondary clarifier sludge is
recirculated to aeration tank because it consists of already activated
microoragnisms. Then the wastewater treated by secondary treatment is allowed
to a series Pressure Sand Filter (PSF) Activated Carbon Filter (ACF) and Ultrafiltration
(UF) to remove the suspended solids and odour from treated wastewater. Finally
the treated wastewater enters the Reverse Osmosis (RO) unit where Total
Dissolved Solids (TDS) are removed from the permit meanwhile TDS concentration
increases in the reject.

 

1.4
Sewage Treatment Plant (STP)

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The
STP
has capacity of 10KLD
and the units are shown in fig 1.3. The Domestic wastewater
generated from canteen, flushing, and floor cleaning is collectively passed
through the screen chamber to remove the egg shells and other things present in
the wastewater, oil generated from canteen is removed in oil and grease tank. The
quality and quantity of the wastewater is maintained in the equilization tank
then it’s allowed to pre-aeration tank where the wastewater comes in contact
with atmospheric air, by this way aeration process starts from pre-aeration
tank naturally without providing any diffusers. The aeration given to wastewater
through natural aeration process is not sufficient so the pre-aerated wastewater
is then allowed to aeration tank where fine diffusers are provided to give
sufficient amount of air. Here the aeration tank is provided with Moving Bed
Biofilm Reactor (MBBR) concept. Where polyethylene innert media of 1.5 m3
volume and 0.5 m height provides site for microbial growth and these microbes
degrade the waste by taking up as their food, once the microorganisms enters
the endogenious phase the film detaches from the media and settle to the bottom
of settling tank when the wastewater is allowed to settling tank. Then the over
flowed water from sellting tank is sent to clarifier for clarification purpose
later it is sent to PSF and ACF to remove the TSS and odour, finally treated
wasrewater goes to ultravoilet unit for disinfection then the treated water is
stored in a tank of capacity 7.2m3. Sludge generated from treatment
process is sent to filter press for dewatering, formed filter cakes are used as
manure for gardening.

 

 

 

 

 

 

 

 

 

 

 

 

 

                                                                     Bar
screen

 

 

Oil Skimmer

 

                                                      
Equalization Tank

 

 

Flash mixer

(Alum dosing)

 

 

Flocculator

 

  
Primary clarifier                                                                                  

                                                                                                          
Sludge holding tank   

Aeration Tank 
                                          

 

 

 Secondary
clarifier                 

                                                                                                                         
Filter press

  PSF
& ACF

 

Ultrafiltration

        
                             

Microfiltration

 

                                                                 

                                                        Reverse Osmosis

           

 

Garden

                                       

                                          Fig 1.2 Treatment processes of ETP in TBK

 

 

                                                        
Bar screen

 

                                                       
Oil Skimmer

                                                   

                                                    
Equalization tank

 

                                                  
   Aeration Tank

Sludge Holding Tank

                                               
MBBR Aeration Tank

                                                                                                            
Filter press

                       

                                               Secondary Settling Tank                         Disposal

                                               
Clarified Water Tank

 

                                                 Pressure Sand Filter

 

                                               Activated
Sand Filter            

 

     Ultra Voilet unit
 

 

                                               
Filtered Water Tank

 

To Irrigation

       

                              Fig 1.3 Sewage
Treatment Plant in TBK

 

1.5
Environmental Impacts of Textile Wastewater

            The rapid but unplanned growth of
industrial clusters, with several factories discharging large amounts of
untreated or poorly treated wastewater leds to serious localized water
pollution (Assefa and Sahu, 2016). The
untreated textile wastewater can cause rapid depletion of dissolved oxygen if
it is directly discharged into the surface water sources due to its high BOD
value. The effluents with high levels of BOD and COD values are highly toxic to
biological life. The high alkalinity and traces of chromium which is employed
in dyes adversely affect the aquatic life and also interfere with the
biological treatment processes (Palamthodi et al., 2011). Wastewater contaminated by dyes represents a
relevant issue associated with several industries. Dyes, even at very low
concentrations, reduce wastewater transparency and oxygen solubility and are
often toxic and recalcitrant. Moreover, these dyes and chemicals are toxic,
carcinogenic or mutagenic for various organisms (Karekar et al., 2014). The
colloidal matter present in oily scum increases the turbidity and gives the
water a bad appearance and foul smell. It prevents the penetration of sunlight
necessary for the process of photosynthesis when it is discharged into water
bodies and also hinders with self purification process of water.

 

In addition when this effluent is
allowed to flow in the fields it clogs the pores of the soil resulting in loss
of soil productivity. The texture of soil gets hardened and penetration of
roots is prevented. The wastewater that flows in the drains corrodes and
incrustates the sewerage pipes. If allowed to flow in drains it effects the
quality of drinking water in hand pumps making it unfit for human consumption.
It also leads to leakage in drains increasing their maintenance cost. Such
polluted wastewater can be a breeding ground for many kind of microorganisms
such as bacteria and viruses. Textile effluent is a cause of significant amount
of environmental degradation and human illnesses. About 40 percent of globally
used colorants contain organically bound chlorine which is a known carcinogen.
All the organic materials present in the wastewater from a textile industry are
of great concern in water treatment because they react with many disinfectants
especially chlorine.

1.6 Permissible
Limit for the Disposal of ETP and STP Treated Effluent

            The wastewater treated from both ETP and STP should meet
the standard specified by the Karnataka State Pollution Control Board and the
same is given in Table 1.1 and 1.2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 1.4 General Discharge
Standards for Effluent Treatment Plant

Parameters

Standards
for Inland      Water Surface  (mg/L)

Standards for Land Disposal  (mg/L)

Colour and Odour

See Note.

See Note.

Suspended Solids    (SS)

100

200

pH

5.5-9.0

5.5-9.0

Oil and Grease

10

10

Biological oxygen demand (BOD)

30

100

Chemical oxygen demand (COD)

250

250

Total Dissolved Solids (TDS)

2100

2100

Sulphide
 

02

Residual Chlorine

1.0

Ammonical nitrogen

50

Nitrate Nitrogen

10

Phosphate

5.0

 

                                                                                                    
  Source: Environmental (Protection)
rules, 1986

 

 

Note: All effort should be made to remove colour and
unpleasant odour as far as practicable.

 

        

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.5   Effluent discharge standards for Sewage Treatment Plant

Parameters

 Standards (mg/L)

pH

6.5-9.0

Biological oxygen demand (BOD)

10

Total Suspended Solids (TSS)

20

Total residual chlorine

01

Oil and Grease

10

Chemical Oxygen Demand (COD)

50

Ammonia nitrogen

5

Total nitrogen

10

Fecal Coliform (MPN/100 ml)