Md. Shah Paran

BTX-110300161

Presentation on Wastewater Characterization

Presented by

Supervisor Md. Tanjim Hossain Lecturer & Co-ordinator Dept. of Textile Engineering

ID Name Remark110300161 Md Shah Paran120100079 Abdul Waras

Wastewater CharacterizationThe wastewater characterized by1) pH Scale2) Total Suspended Solid (TSS)3) Total Dissolved Solid (TDS)4) Dissolved Oxygen (DO)5) Chemical Oxygen Demand (COD)6) Biological Oxygen Demand (BOD)

The acceptable range for environment of this parameter

Parameter RangepH 6-9TSS Less then 150 ppmTDS Less than 2100 ppmDO 4.5-8

COD Less than 200 ppmBOD Less than 50 ppm

pH

pH is the abbreviation of pondus hydrogen pH = -log [H+]

[H+] is in molar concentration

pH measurement is required--To produce products with defined properties-To protect equipment-For research and development

pH of a material is determined by

Electrochemical method Depends on hydrogen activity in the solution It consists of two electrodes1. Measuring electrode 2. Reference electrode

Measuring electrode (Glass electrode)

Dependent on hydrogen activity Glass membrane is sensitive to H+ ions

Reference electrode

• insensitive to the H+ ions in the solution

• most widely used is thesilver/silver chloride electrode• another commonly usedreference electrode is thecalomel electrode

Other methods

Optical Methods -Indicator papers ISFET electrode

Total Suspended Solids (TSS)

The solids retained on a filter paper of pore size 2.0 µm or smaller, during the filtration of the sample water

Total Suspended Solids are the amount of filterable solids in a water sample. Samples are filtered through a glass fiber filter. The filters are dried and weighed to determine total suspended solids in mg/L.

Determination of TSS Prepare a 0.45 micron filter using wash-dry-cool cycle Seat filter with DI water prior to filtration Pippet a measured volume into filtration apparatus

from stirred sample Wash filter with 3 x 10 mL washings DI water Apply suction for 3 minutes after washing Transfer to aluminum dish for support Dry in the oven at 103-105 °C overnight (should be 1

h) Place in a desiccator to cool to room temperature,

reweigh to the nearest 0.1 mg Calculate TSS in mg/L

CalculationsTotal suspended solids (TSS) :The total suspended solids (TSS) is given by

thefollowing formula:mg/L Total suspended solids = ( A-B) × 1000 / ml

sampleWhere,A = weight of filter disk with dried residue B = weight of filter disk only

Total Dissolved Solids (TDS)

The solids that pass through the filter paper during the filtration of sample water

Total Dissolved Solids are those solids (inorganic + organic) that pass through a filter of 2.0 μm or smaller. They are said to be non-filterable. After filtration the filtrate (liquid) is dried and the remaining residue is weighed and calculated as mg/L of Total Dissolved Solids

Determination of TDS1. Dry a clean dry beaker at 103-105 °C for at least 1

hour2. Desiccate until cool and weigh to nearest 0.1 mg3. Filter 50.0 mL through a 0.45 μm filter paper into

clean dry beaker using technique described above4. Heat the sample to just below boiling and reduce

the volume to 10 mL5. Allow the beaker to cool and dry in the oven at 103-

105 °C overnight6. Remove the beaker and place in a desicator to cool

to room temperature, reweigh to the nearest 0.1 mg7. Calculate TDS in mg/L

CalculationsTotal Dissolved solids (TDS): The total dissolved solids are given by the formula: mg/L Total dissolved solids = ( A-B) × 1000 / ml

sampleWhere; A = weight of dried residue + dish weight (mg)B = weight of dish (mg)

Abdul Waras

BTX-120100079

Dissolved Oxygen (DO) Dissolved Oxygen is the amount of gaseous

oxygen (O2) dissolved in the water. Oxygen enters the water by direct absorption from the atmosphere, by rapid movement, or as a waste product of plant photosynthesis.  Water temperature and the volume of moving water can affect dissolved oxygen levels. Oxygen dissolves easier in cooler water than warmer water.

Adequate dissolved oxygen is important for good water quality and necessary to all forms of life.   Dissolved oxygen levels that drop below 5.0 mg/L cause stress to aquatic life. Lower concentrations cause greater stress. Oxygen levels that go below 1-2 mg/L for a few hours may result in large fish kills.

Determination of DOMaterials: 300.0 ml BOD bottles or SOLA (glass)

bottles with cap 250.0 ml graduated cylinder 500.0 ml Erlenmeyer flasks 1.0 ml Pipettes Rubber aspirator Titration set-up

Procedure:

Collect samples in a 300 mL SOLA bottle Add 2ml of manganous sulfate solution Add 2 ml of alkaline-iodide-sodium azide

solution Shake the bottle by inverting several

times Allow solution to settle Add 2ml of conc. sulfuric acid Shake well until precipitate is dissolved

Titration Procedure:

Pour 200ml of sample from the SOLA bottle into an Erlenmeyer flask

If the solution is reddish-brown in color, titrate with 0.0250 N sodium thiosulfate

If the solution has no reddish-brown color, or is only slightly colored,

add a small quantity (approx. 1 mL) of starch

indicator.

Biochemical Oxygen Demand (BOD)

BOD is the amount of dissolved oxygen needed by aerobic biological organism in a body of water to breakdown organic material present in a given water sample at certain temperature over a specific time period (5 days).

HYPOXIA: When dissolve oxygen content below 3.0 mg/L. Many Species move elsewhere and immobile species may die.

ANOXIA: When dissolve oxygen content below 0.5 mg/L. All aerobic species will die.

Determination of BOD

A. DilutionDilution Factor: The dilution factor, DF, is the ratio of

the final volume to the volume of sample therein. (e.g., for the bottle method, the volume of the BOD bottle, usually 300 mL; for the graduated bottle, usually 300 mL; for the graduated cylinder method, the volume of the cylinder, usually 1000 mL).

DF for the bottle method = {Volume of Diluted Mixture÷Volume of Sample in Mixture

B. DO fixation 1. Slowly siphon three portions of aerated dilution water into

three separate BOD bottles. Avoid adding atmospheric O2to dilution water.

2. To two of the three BOD bottles, add 1 2.To two of the three BOD bottles, add 1 ml MnS04solution, followed by 1 ml alkali-iodide-azide reagent. Submerge pipette tips in sample when adding reagents. Rinse tips well between uses.

3. Stopper carefully to exclude air bubbles; mix by inverting bottle several times.

4.When precipitate has settled to about half the bottle volume, carefully half the bottle volume, carefully remove the stopper and add 1.0 ml conc. sulfuric acid. Re-stopper and mix by gentle inversion until the iodine is uniformly distributed throughout the bottle.

C. DO Measurement5. Transfer 203 ml of sample into conical flask and

titrate with 0.0250N sodium thiosulfate to a pale straw color.

6. Add 1-2 ml of starch solution and continue to titrate to first disappearance continue to titrate to first disappearance of the blue color. (200 ml of original dilution water is equal to 203 ml of dilution water plus reagents).

7. Determine the initial concentration of dissolved oxygen in one bottle of the mixture of sample and dilution water (DO), and in one of the water (DOinitial), and in one of the bottles containing only dilution water.

8. Place the other bottles in the incubator9. Incubate the blank dilution water and the diluted

samples for 5 days in the dark at 20 °C. 10. After 5 days, remove the bottles, fix the DO

and measure the DO (DOfinal) DO and measure the DO (DOfinal)

11. Calculate BOD5 BOD5(mg/L) = {DOinitial(mg/L) of first bottle -

DOfinal(mg/L) of second bottle} x dilution factor

Chemical Oxygen DemandCOD is the total amount of oxygen required to

chemically oxidize the bio degradable and non-biodegradable organic matter.

It is expressed in milligrams per liter (mg/L) also referred to as ppm (parts per million), which indicates the mass of oxygen consumed per liter of solution.

Determination of COD Water sample is refluxed in strong acidic solution

with a known excess amount of potassium dichromate.

After digestion, the remaining unreduced K2Cr2O7 is titrated with Ferrous Ammonium Sulfate (FAS)to determine K2Cr2O7 consumed.

This gives us the oxidizable organic matter in terms of oxygen equivalent.

Procedure1. Wash 300 ml round bottom refluxing flask.2. In refluxing flask put one spatula of HgSO4 + 10 ml

sample + 5ml K2Cr2O7 + 15 ml concentrated H2SO4.3. Add small amount of silver sulphate.4. Shake well and reflux for 2 hr.5. Cool and add little amount of distilled water to the

flask through the condenser6. Titrate the solution in the flask against FAS using

Ferrion indicator7. End point green color to reddish brown

For blank, add 10 ml distilled water instead of sample. Rest of the procedure is the same.

CALCULATIONS The COD in mg/l is determined by the formula,

COD mg/l = (A-B)xNx8000ml sample taken

A = ml of FAS required for blank. B = ml of FAS requires for sample.

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