Oxidization Tank

Waste water from the knit dyeing project destroy the quality of water body in which they are exposed affecting the marine life. It also has a harmful effect of sewerage handling system and agricultural land. The characteristics and effect of effluent are as follows

pH:

The waste water may be either acidic or alkaline.

If acidic

  1. It may cause corrosion of pipeline.
  2. Can cause destruction of aquatic life

If alkaline

  1. It may cause adverse effect on aquatic life
  2. Incrustation in sewers and damage corps by impairing their growth

DISSOLVE SOLIDS:

The dissolve solid may be either organic or inorganic. The can cause reduction in dissolve oxygen in waste water, disease and discomfort, scale in pipelines and other equipments, accelerate algal growth, increase hardness of water and enhance metal corrosion

SUSPENDED SOLIDS:

Suspended solids increase

  1. Turbidity
  2. Interferes light transmitting property of water
  3. Destroy photosynthesis and oxygen transmission process
CriteriaAverage quality of textile effluentMinimum std required to drain
BOD300 mg/l20-40 mg/l
COD1000 mg/l120-160 mg/l
Suspended solid200 mg/l20-40 mg/l
Settle able solid0-5 mg/lNo traces
Ammonia20-30 mg/l4-8 mg/l
Phosphorus3-5 mg/l3-5 mg/l
Surfactant30-40 mg/l0.5-2 mg/l
Chloride1000-1500 mg/l1000-1500 mg/l
Sulphate1000-1500 mg/l1000-1500 mg/l
Oil and fats30-40 mg/l<5 mg/l
Phenol3-5 mg/l0.05 mg/l
colorcoloredNot perceptible

The Following standard is given by Bangladesh Department of Environment

Composite Textile Plant and large processing unit ( in which capital investment is more than thirty million taka)

ParametersStandard and presence in a unit of mg/l
pH6.5-9
Suspended Solid100
BOD5 20o C150
Oil and Grease10
Total dissolved solids2100
Wastewater flow100
Total Chromium as Cr2
Sulfide as S2
Phenolic Compounds as C6H5OH5

EFFLUENT TREATMENT AND DISPOSAL SYSTEM

In our country commercially Four-type process are available.

  1. Chemical process
  2. Biological process
  3. Chemical and biological combination process
  4. Chemical Biological and electro coagulation combined process

Typical operation involved in a ETP

CHEMICAL OXYGEN DEMAND-COD

This Means potential overall oxygen requirement of the waste water sample including oxidizable components not determined in the BOD analysis.

STEPBLANKSAMPLE
1Take 20 ml  DM Water in a conical flaskTake Sample in a conical flask as per dilution method
2Add pinch of  Mercury II SulfateAdd pinch of  Mercury II Sulfate

 

 

3Add  5 ml  Silver Sulfate -Sulfuric acid solutionAdd  5 ml  Silver Sulfate -Sulfuric acid solution
4Add 10 ml      Potassium  Dichromate solutionAdd 10 ml      Potassium  Dichromate solution
5Add  25 ml  Silver Sulfate -Sulfuric acid solutionAdd  25 ml  Silver Sulfate -Sulfuric acid solution
6Add glass beadsAdd glass beads

 

 

7Reflux for 2 hoursReflux for 2 hours

 

 

8cooling for 2 hourscooling for 2 hours

 

 

9Add 80 ml Distilled waterAdd 80 ml Distilled water

 

 

11Titrate with Ferrous Ammonium Sulfate

 

 

Titrate with Ferrous Ammonium Sulfate
 

 

12

 

 

TITRATION VALUE= A

 

 

TITRATION VALUE= B

 

DILUTION METHOD

EFFLUENTX-SAMPLE-MLDISTILLED WATER-ML
Collection Sump218
Clarifier Outlet515
UF permeate1010
RO 1 feed1010
RO 2 feed515
RO 3 feed515
RO reject218
Dye bath effluent119
NF permeate218

CHEMICAL OXYGEN DEMAND-COD

TITRATION

BURETT

0.1N ferrous ammonium sulfate

CONICAL FLASK

  • X ml of sample
  • 4-5 drops of Ferrion indicator

TITRATION

Sample Vs 0.1N ferrous ammonium sulfate

ENDPOINT

Bluish green to reddish brown

TITRATIONTitration  of  BlankTitration  of  Sample
Titration valueAB

CALCULATION OF COD -MG/LITRE

(A-B) X 0.1 X8 X1000

Xml OF SAMPLE

X -SAMPLE MLCALCULATION – MG/LT
1(A-B) X  800
2(A-B) X  400
5(A-B) X  160
10(A-B) X  80
15(A-B) X  53.33

BIOCHEMICAL OXYGEN DEMAND-BOD

Biochemical oxygen demand is the measure of the oxygen consuming capabilities of orange matter, water with high BOD indicates the presence of decomposing orange matter and subsequent high bacterial counts that degrade its quality and potential uses.

 

 

Solution A

 

 

Blank

 

 

Sample

 

Take 2 liter distilled waterTake 300ml A solution in BOD bottle without air make 2 sampleTake two sample without air, as per dilution method
Aerate 1 hourCheck initial DO in one sample =  B1Check initial DO in one sample=  S1
Add 2ml ferric chlorideAnother sample Keep in BOD incubator at 20’C For 5 daysAnother sample Keep in BOD incubator at 20’C For 5 days
Add 2ml magnesium sulfate20’C For 5 days

 

27’C For 3 days

 

20’C For 5 days

 

27’C For 3 days

Add 2ml calcium chlorideAfter 5 or 3 days check DOAfter 5 or 3 days check DO
Add 2ml phosphate buffer 

 

DO of the blank is    B2

 

 

DO of the blank is  S2

Add 2ml seed solution

 

 

DILUTION METHOD AND ITS FACTOR

 

 

EFFLUENT

 

 

SAMPLE-ML

 

 

SOLUTION – A

 

 

F

 

 

P

Raw effluent22980.9930.00667
Primary outlet52950.9830.01667
Secondary outlet102900.9670.03333
Ro 1 feed102900.9670.03333
Ro 2 feed52950.9830.01667
Ro 3 feed12990.9960.00333
 

 

TOTAL VOLUME = 300 ML

BIOCHEMICAL OXYGEN DEMAND-BOD

CALCULATION  

Blank solution do-sample do    =    (B1 – B2) – ((S1 – S2) F)

                         Dilution factor                                             P

F- Fraction of sample to total volume                  = 300 – sample ml / 300

P- Fraction of sample to total volume                  = Sample ml /300

BOD SAMPLES TAKEN PROCEDURE

S.NOBOD Range ( approx ) – mg/lVolume of sample – ml

 

 

10-7300
26-21100
312-4250
430-10520
560-21010
6120-4205
7300-10502
8600-21001
91200-42000.5
103000-105000.2
116000-210000.1
1212000-420000.05
1330000-1050000.02

DISSOLVED OXYGEN-DO

 

 

STEP

 

 

BOD BOTTLE

1Take 300ml SAMPLE in BOD bottle without air

 

 

2Add 2ml manganous sulfate

 

 

3Add 2ml alkali iodide, sodium azide solution

 

 

4Immediately fix the stopper

 

 

5Keep 10 min for settling

 

 

6Add 2ml conc. Sulfuric acid

 

 

7Shake well

 

 

8Transfer 200ml in conical flask

 

 

9Titrate with 0.025 N sodium thio sulfate

 

 

BURETTE

0.025 N Sodium thio sulfate solution

CONICAL FLASK

  • 200 sample
  • 4-5 drops of starch indicator

TITRATION

Sample Vs 0.025 N Sodium thio sulfate solution

ENDPOINT                      Disappearance of dark blue

CALCULATION

TITRATE VALUE X 0.025 X8 X1000  -ppm

200 ml OF SAMPLE

TITRATE VALUE X 1 – ppm