Analysis of water pollution BY Muhammad Nadeem Ashraf University of poonch, Rawalakot.

2. SES_311
Introduction to soil and environment
Department of Soil & Environmental Sciences
Faculty of Agriculture Rawalakot
University of Poonch, awalakot.
email: nadeemawan17@gmail.com

3. Why Water analysis is necessary?
 To asses water quality
 To provide pure water to public for drinking
 To analyse microbial organisms
 Preventive measure and effective disinfection
procedure
 Sewagw and waste water analysed

4.  Physical assesment
• Temperature
• Ph
• Turbidity
• TSS
 Chemical assesment
• Acidity
• Alkalinity
• COD
• Chemical substances
 Biological assesment
 BOD
 Microbiological

5.  Colour in water is due to suspended particles in
solution,even pure water is not colorless(pale-green)
 Colour of water may be caused by Fe,Mn,Cu,metals,Iron.
 humus,algae,weeds,protozoa etc.
 Colour can be compared visually or Photoelectrically.
 Colour is measured with an instrument known as
Tintometer.
 Yellow color indicates the presence of O.M
 Yellow red color indicates.
 True color can be estimated by visual comparispon with
platinum cobalt standard solution, unit is measured on
cobalt scale.

6.  Turbidity in water mainly arises from colliodal
material and fine suspended particles.
 Turbidity can be measured by
absorptiometrically(visual methods) and
nephelometrically(instrumental methods)
 Another methods used to measure turbidity is
Turbidity Rod which has a platinum needle.
 Jackon,s turbidimeter which consists of metal
stand over which a metal container is placed.

7.  Odour in water are sue to the presence of
microscopic organisms or decaying vegetation
including algae, fungi, bacteria, H2S, N, P, S
compounds.
Determination of Odour:
 For dermination of odour place 250ml of sample in
a 500ml wthite mouth erlenmeyer flask & sniff the
odour.

8.  Dissolve mineral matters in water produce tastes but
not odour.
 If faint bitter taste may be due to the presence of
Sulphate while soapy or inky taste may be due the
excess of sodium bicarbonate.
 Way to remove objectionable taste & odour from water
is to pass it through a filter bed containing activated
charcoal, if finely divided form of carbon. The
enormous surface area enables it to absorb large
quantities of impurities.

9.  Surface water differs considerably in temperature
b/w winter & summer.
 Temperature measurment are usefull in detecting
an unsuspected suorce of pollution, in calculating
alkalinity and in industrial water supplies for heat
tranmision calculations.

10.  pH a measure of hydrogen ion activity is used to
express the intensity of acidic or alkaline condition of a
solution. It is an also important factor in water analysis.
 pH of a sample can be determine by electrometrically.
it involves the measurment of EMF of a cell comprising
an glass electrode response to hydrogen ion and
refrence electrode.
 pH meters used for measurement.
 The desirable pH range for drinking water is
7-8.5

11.  EC is a measure of water’s capacity to convey
electric current.its unit is micro Siemns/cm3
 Conductivity of water varies directly with
temperature and is proportional to its dissolved
mineral matter content.
 It is an important to check the purity of distilled
water. Distilled water with conductivity more the 2
should not be used for water analysis.

12.  500ml of a sample is taken in volumetric flask and
allowed to filter through a dried and weighed
Gooch crucible containing an asbestos mat.The
suspended solids retained in the crucible or
washed with distilled water to remove chloride.
The crucible is finally dried, cooled in a desicator
and weighed.the weighed of crucible is equalent
to suspended impurities present.

13.  It is the power of water to neutralized hydroxyl ions
and is expressed in terms of CaCO3. water attains
acidity fron industrial effulents etc.
 Take 50ml of sample dechlorinated in a 250ml conical
flask add 2 drops of methyl orange indicator and titrate
with 0.02 N-NaOH solution till faint orange colour.
 Methyl orange point is a measure of mineral acidity.
 Amount of sodium hydroxide to reach pH 8.3
(phenolphthaline end point) is a measure of total
acidity.

14.  Alkalinity of water is generally due to the presence
of carbonate and hydroxide ion.
 It is measured by titrimetric method.

15.  Calsium in water mainly due to the presence of
limestone,gypsum,dolomite.
 The determination of Ca is required potable water.
 EDTA titrimetric method and gravimetric method are
used for determination of calcium.
 In EDTA titrimetric method Ca reacts with EDTA in the
presence of a selective indicator at a high pH and Mg
is allowed to precipitate as its hydroxide.
 Ca2+ + 2EDTA Ca(EDTA)2

16.  Magnesium salts occur in natural waters,sea
waters(130ppm).
 It is measured by gravimetric method or
photometric method.
 It may also be calculated as the difference
between total hardness and Ca hardness as
under:
 Mg(as CaCO3)mg/L =mg/L total hardness as
CaCO3 –mg/L calcium hardness as CaCO3.

17. Ammonia
 N is present in water in the form of ammonia, nitrates
& nitrites. The presence of the substances in water
indicates the the presence of organic contamination.
 The amount of free ammonia is determine by boiling
the sample of water. The quantitiy of ammonia in
potable water should not be greater then 0.15 ppm.
 Ammonia is calorimrtrically measured using Nessler,s
reagent.

18.  Nitrites are obtained by the oxidation of ammonia,
nitrites should never be present in potable water.
 The presence of nitrites in water can be determine
by adding sulphonilic and naphthamine.
 The permissible limit of Nitrate in drinking water is
10mg/L.
 The presence of nitrate in water bodies caused
mathemoglobinemia.
 It can be measured by Brucine method.

19.  Cyanide
 Sulphate
 Sulphide
 Chloride
 Fluoride
 Fluoridation

20.  It is necessary to destroy these chemical
substances by digestion with strong acids.
Digestion destroys the O.M and brings metallic
compounds in suspension to solution.

21.  Arsenic occur in water as a result of mineral
dissolution,industrial waste or application of
insectisides.
 The presence of As as 100mg in water cause
poisoning,it can cause chronic effect.
 It can be measured by Gutzeit method.

22.  Cd enters water through industrial wastes,it is
toxic and poisoning can cause human kidney.
 It can be measured in water sample by detected
by dinitrophenyl carbazide.

23.  Beryllium (atomic absorption method)
 Copper (spectrophotometric method)
 Chromium (diphenylcarbazide method)
 Lead (atomic absorption method)
 Iron (spectrophotometric method)
 Selenium (spectrophotometric method)
 Mercury (dithizone method)

24. List of National Secondary Drinking Water Regulations
Contaminant Secondary Standard
Aluminum 0.05 to 0.2 mg/L
Chloride 250 mg/L
Color 15 (color units)
Copper 1.0 mg/L
Corrosivity noncorrosive
Fluoride 2.0 mg/L
Foaming Agents 0.5 mg/L
Iron 0.3 mg/L
Manganese 0.05 mg/L
Odor 3 threshold odor number
pH 6.5-8.5
Silver 0.10 mg/L
Sulfate 250 mg/L
Total Dissolved Solids 500 mg/L
Zinc 5 mg/L

25. Substances Max. Allowable limit
1.Standards of chemical & physical
quality
(a) Toxic metals
Lead 10ug/L
Arsenic 10ug/L
Barium 0.10mg/L
Cadmium 0.01mg/L
Chromium 0.05mg/L
Selenium 5ug/L
Mercury 1ug/L
(b) Substsnces affectin health
Fluoride 1.5mg/L
Nitrate 45mg/L

26. Substances Max. Allowable limit
(c) Substances affecting potability of water
Total solids 1500mg/L
Colour 50 units
Turbidity 25 units
Taste -
Odour -
Iron 1.0mg/L
Manganese 0.5mg/L
Copper 1.5mg/L
Zinc 15mg/L
Calcium 200mg/L
Magnesium 150mg/L
Chlorine 0.1mg/L
Sulphate 400mg/L
Mangnesium + Sodium sulphate 1000mg/L
Phenonic compounds 0.002mg/L
CCE 0.5mg/L

27.  BOD is the measure of the dissolve oxygen required
by the microbes in polluted water, it is measured in
mg/L.
 During this process dissolve oxygen is consumed
and micro-organism transform the ollutants into non-
hazardous compounds.
microbes
 CH2O+O2 CO2 +H2O+M.Org
O.M aerobic oxidation

28.  The water sample is first saturated with oxygen and
then incubated at constant temperature(20C) for 5-
days.
 This allows the sufficient time for micro-
organism in polluted water to affect oxidation of
pollutants.
 After 5-days, the remaining amouny of dissolved
oxygen is determined and BOD is obtained by
substraction.
 The 5-day BOD(ppm) analysis is considerd as an
accepted stndard test.

29.  Drinking water should have 5-day BOD of less
than 1.5mg/L.
 BOD of raw sewge ranges from 200-400mg/L
 Major contributor to BOD are chemical industries,
pulp and paper and food processig industry.
 BOD of very clean water is 1mg/L, clean water is
2mg/L and unfit for drinking water is 5mg/L.

30.  COD is a measure of oxygen required to
breakdown the organic matter.
 In BOD breakdown of organic matter is affected
by micro organisms but in COD the degradation is
affected by some chemical oxidizing agent like
Potasium dichromite .

31.  The water sample is treated with an oxidizing
agent(K2Cr2O7) which oxidizes most of the polluting
substances including those which are resistant to
microbial oxidation.
 The unused potassium dichomite is determine by
back titration with a suitable reducing agent like
Mohr’s salt.
 The amount of oxygen used in oxidation can be
calculated as:
K2Cr2O7 + 4H2SO4 K2SO4+Cr2(SO4)3+4H2O+3(O)

32. COD in mg/L Status
0-5 Very clean water, used for drinking
5-20 Fairly clean
20-100 Unfit for drinking

33. Microbiological
parameters
WHO standards EU standards
Escherichia coli Not mentioned 0 in 250 ml
Enterococci Not mentioned 0 in 250 ml
Pseudomonas
aeruginosa Not mentioned 0 in 250 ml
Clostridium
perfringens Not mentioned 0 in 100 ml
Coliform bacteria Not mentioned 0 in 100 ml
Colony count 22oC Not mentioned 100/ml
Colony count 37oC Not mentioned 20/ml