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What is Oxidization Tank

What is Oxidization Tank? Describe the Process.

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

 

Criteria Average quality of textile effluent Minimum std required to drain
BOD 300 mg/l 20-40 mg/l
COD 1000 mg/l 120-160 mg/l
Suspended solid 200 mg/l 20-40 mg/l
Settle able solid 0-5 mg/l No traces
Ammonia 20-30 mg/l 4-8 mg/l
Phosphorus 3-5 mg/l 3-5 mg/l
Surfactant 30-40 mg/l 0.5-2 mg/l
Chloride 1000-1500 mg/l 1000-1500 mg/l
Sulphate 1000-1500 mg/l 1000-1500 mg/l
Oil and fats 30-40 mg/l <5 mg/l
Phenol 3-5 mg/l 0.05 mg/l
color colored Not 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)

Parameters Standard and presence in a unit of mg/l
pH 6.5-9
Suspended Solid 100
BOD5 20o C 150
Oil and Grease 10
Total dissolved solids 2100
Wastewater flow 100
Total Chromium as Cr 2
Sulfide as S 2
Phenolic Compounds as C6H5OH 5

 

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.

STEP BLANK SAMPLE
1 Take 20 ml  DM Water in a conical flask Take Sample in a conical flask as per dilution method
2 Add pinch of  Mercury II Sulfate Add pinch of  Mercury II Sulfate

 

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

 

7 Reflux for 2 hours Reflux for 2 hours

 

8 cooling for 2 hours cooling for 2 hours

 

9 Add 80 ml Distilled water Add 80 ml Distilled water

 

11 Titrate with Ferrous Ammonium Sulfate

 

Titrate with Ferrous Ammonium Sulfate
 

12

 

TITRATION VALUE= A

 

TITRATION VALUE= B

 

 

DILUTION METHOD

EFFLUENT X-SAMPLE-ML DISTILLED WATER-ML
Collection Sump 2 18
Clarifier Outlet 5 15
UF permeate 10 10
RO 1 feed 10 10
RO 2 feed 5 15
RO 3 feed 5 15
RO reject 2 18
Dye bath effluent 1 19
NF permeate 2 18

 

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

 

TITRATION Titration  of  Blank Titration  of  Sample
Titration value A B

 

CALCULATION OF COD -MG/LITRE

(A-B) X 0.1 X8 X1000

Xml OF SAMPLE

 

X -SAMPLE ML CALCULATION – 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 water Take 300ml A solution in BOD bottle without air make 2 sample Take two sample without air, as per dilution method
Aerate 1 hour Check initial DO in one sample =  B1 Check initial DO in one sample=  S1
Add 2ml ferric chloride Another sample Keep in BOD incubator at 20’C For 5 days Another sample Keep in BOD incubator at 20’C For 5 days
Add 2ml magnesium sulfate 20’C For 5 days

27’C For 3 days

 

20’C For 5 days

27’C For 3 days

Add 2ml calcium chloride After 5 or 3 days check DO After 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 effluent 2 298 0.993 0.00667
Primary outlet 5 295 0.983 0.01667
Secondary outlet 10 290 0.967 0.03333
Ro 1 feed 10 290 0.967 0.03333
Ro 2 feed 5 295 0.983 0.01667
Ro 3 feed 1 299 0.996 0.00333
 

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.NO BOD Range ( approx ) – mg/l Volume of sample – ml

 

1 0-7 300
2 6-21 100
3 12-42 50
4 30-105 20
5 60-210 10
6 120-420 5
7 300-1050 2
8 600-2100 1
9 1200-4200 0.5
10 3000-10500 0.2
11 6000-21000 0.1
12 12000-42000 0.05
13 30000-105000 0.02

 

DISSOLVED OXYGEN-DO

 

STEP

 

BOD BOTTLE

1 Take 300ml SAMPLE in BOD bottle without air

 

2 Add 2ml manganous sulfate

 

3 Add 2ml alkali iodide, sodium azide solution

 

4 Immediately fix the stopper

 

5 Keep 10 min for settling

 

6 Add 2ml conc. Sulfuric acid

 

7 Shake well

 

8 Transfer 200ml in conical flask

 

9 Titrate 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

About Engr. Kh. Mashiur Rahman

He is Garment Automation Technologist and Editor in Chief of Autogarment. He is certified Echotech Garment CAD Professional-China, Aptech-India, NCC-UK and B.Sc. in CIS- London Metropolitan University, M.Sc. in ICT-UITS. He is working as a Successful Digital Marketer and Search Engine Specialist in RMG sector during 2005 to till now. Contact him- apparelsoftware@gmail.com

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