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