EXPERIMENTAL
Every water sample in contact with the atmosphere contains dissolved gases
such as oxygen and carbon dioxide. Similarly every water sample in contact with
sediments and rock contains dissolved species of silicon and calcium. In most
cases, such water is not considered to be polluted. It has been found that open
ocean sample of water contains some trace elements as- As, Cd , Cr, Co, Cu, Fe,
Pb, Mn, Mo, Ni, Zn, U etc. and in Antarctic snow some cations and anions as- Cl-,
NO3-, SO4--, Br-, PO4---, F-, Na+, K+, Mg++, Ca++ and NH4+ have been detected .
Clearly there is no such thing is as pure water in the natural environment in the
chemical sense. Just as total purity of water is impossible.
If we define a pollutant as a substance which adversely alters the
environment changing the growth rate of species, interferes with food chain, is
toxic, or interfere with health, comfort, amenities etc. then it is necessary to set
standards or guidelines in order to indicate that water, whose chemical properties
exceed the limits of the standards, may cause a particular environmental
interference. Among the standards, some guidelines have been established which
includes:-
(a) Physical properties such as colour, odour, turbidity and temperature.
(b) Chemical properties such as pH, total dissolved solids (TDS), salinity,
hardness, BOD, detergents etc.
(c) For specific elements, complex ions, organic compounds, and levels of
radioactivity for radiological properties.
(d) For microbiological properties.
3.01. MEASUREMENT:Water pollution may be analyzed through several broad categories of
methods: physical, chemical and biological. Most involve collection of samples,
followed by specialized analytical tests. Government agencies and research
organizations have published standardized, validated analytical test methods to
facilitate the comparability of results from disparate testing events89.
3.01.1. Sampling: - Sampling of water for physical or chemical testing can be
done by several methods, depending on the accuracy needed and the characteristics
of the contaminant. Many contamination events are sharply restricted in time, most
commonly in association with rain events. For this reason "grab" samples are often
inadequate for fully quantifying contaminant levels. Scientists gathering this type
of data often employ auto-sampler devices that pump increments of water at either
time or discharge intervals.
Sampling for biological testing involves collection of plants and/or animals
from the surface water body. Depending on the type of assessment, the organisms
may be identified for biosurveys (population counts) and returned to the water
body, or they may be dissected for bioassays to determine toxicity.
3.01.2. Physical testing: - Common physical tests of water include temperature,
solids concentration like total suspended solids (TSS) and turbidity.
3.01.3. Chemical testing: - Water samples may be examined using the principles
of analytical chemistry. Many published test methods are available for both
organic and inorganic compounds. Frequently used methods include pH,
biochemical oxygen demand (BOD), chemical oxygen demand (COD), nutrients
(nitrate and phosphorus compounds), metals (including copper, zinc, cadmium,
lead and mercury), oil and grease, total petroleum hydrocarbons (TPH), and
pesticides.
3.01.4. Biological testing: - Biological testing involves the use of plant, animal,
and/or microbial indicators to monitor the health of an aquatic ecosystem.
3.02. Control
3.02.1. Domestic sewage: - Domestic sewage is 99.9% pure water; the other 0.1%
is pollutants. While found in low concentrations, these pollutants pose risk on a
large scale.10 In urban areas, domestic sewage is typically treated by centralized
sewage treatment plants. In the U.S., most of these plants are operated by local
government agencies, frequently referred to as publicly owned treatment works
(POTW). Municipal treatment plants are designed to control conventional
pollutants: BOD and suspended solids. Well-designed and operated systems (i.e.,
secondary treatment or better) can remove 90 percent or more of these pollutants.
Some plants have additional sub-systems to treat nutrients and pathogens. Most
municipal plants are not designed to treat toxic pollutants found in industrial
wastewater.49 Cities with sanitary sewer overflows or combined sewer overflows
employ one or more engineering approaches to reduce discharges of untreated
sewage, including:

Utilizing a green infrastructure approach to improve storm water
management capacity throughout the system, and reduce the hydraulic
overloading of the treatment plant50.

Repair and replacement of leaking and malfunctioning equipment46.

Increasing overall hydraulic capacity of the sewage collection system (often
a very expensive option).
A household or business not served by a municipal treatment plant may have an
individual septic tank, which treats the wastewater on site and discharges into the
soil. Alternatively, domestic wastewater may be sent to a nearby privately owned
treatment system (e.g. in a rural community).
3.02.2. Industrial wastewater: - Some industrial facilities generate ordinary
domestic sewage that can be treated by municipal facilities. Industries that generate
wastewater with high concentrations of conventional pollutants (e.g. oil and
grease), toxic pollutants (e.g. heavy metals, volatile organic compounds) or other
non conventional pollutants such as ammonia, need specialized treatment systems.
Some of these facilities can install a pre-treatment system to remove the toxic
components, and then send the partially treated wastewater to the municipal
system. Industries generating large volumes of wastewater typically operate their
own complete on-site treatment systems. Some industries have been successful at
redesigning their manufacturing processes to reduce or eliminate pollutants,
through a process called pollution prevention. Heated water generated by power
plants or manufacturing plants may be controlled with:

Cooling ponds, man-made bodies of water designed for cooling by
evaporation, convection, and radiation

Cooling towers, which transfer waste heat to the atmosphere through
evaporation and/or heat transfer

Cogeneration, a process where waste heat is recycled for domestic and/or
industrial heating purposes51.
3.02.3. Agricultural wastewater: - Nonpoint source controls Sediment (loose
soil) washed off fields is the largest source of agricultural pollution in the
United States. Farmers may utilize erosion controls to reduce runoff flows and
retain soil on their fields. Common techniques include contour plowing, crop
mulching, crop rotation, planting perennial crops and installing riparian
buffers52,164. Nutrients (nitrogen and phosphorus) are typically applied to
farmland as commercial fertilizer; animal manure; or spraying of municipal or
industrial wastewater (effluent) or sludge. Nutrients may also enter runoff from
crop residues, irrigation water, wildlife, and atmospheric deposition.52 Farmers
can develop and implement nutrient management plans to reduce excess
application of nutrients. To minimize pesticide impacts, farmers may use
Integrated Pest Management (IPM) techniques (which can include biological
pest control) to maintain control over pests, reduce reliance on chemical
pesticides, and protect water quality.53 Point source wastewater treatment Farms
with large livestock and poultry operations, such as factory farms, are called
concentrated animal feeding operations or confined animal feeding operations
in the U.S. and are being subject to increasing government regulation.54,74
Animal slurries are usually treated by containment in lagoons before disposal
by spray or trickle application to grassland. Constructed wetlands are
sometimes used to facilitate treatment of animal wastes, as are anaerobic
lagoons. Some animal slurry are treated by mixing with straw and composted at
high temperature to produce bacteriologically sterile and friable manure for soil
improvement.
3.02.4. Urban runoff (storm water):- Effective control of urban runoff
involves reducing the velocity and flow of stormwater, as well as reducing
pollutant discharges. Local governments use a variety of stormwater
management techniques to reduce the effects of urban runoff. These techniques,
called best management practices (BMPs) in the U.S., may focus on water
quantity control, while others focus on improving water quality, and some
perform both functions.56 Pollution prevention practices include low impact
development techniques, installation of green roofs and improved chemical
handling (e.g. management of motor fuels & oil, fertilizers and pesticides). 57
Runoff mitigation systems include infiltration basins, bioretention systems,
constructed wetlands, retention basins and similar devices.29,112 Thermal
pollution from runoff can be controlled by stormwater management facilities
that absorb the runoff or direct it into groundwater, such as bioretention systems
and infiltration basins. Retention basins tend to be less effective at reducing
temperature, as the sun may heat the water before being discharged to a
receiving stream.59
3.03. MATERIALS AND METHOD:In each month four different water samples have been taken on the date 7 th
15th and 25th during the day time between 10.00 am to 05.00 pm from dug wells
(A), hand pumps (B), IM II hand pumps (C) and tube wells (D) from the selected
sites and the average of the readings on these days was reported as the
corresponding result of the month. The different sampling locations are given in
table-3.01. Samples were collected in 2L plastic cans and brown glass bottles with
necessary precautions without adding any preservative. The bottles were rinsed
with double distilled water and dried before sampling and tightly sealed after
collection and labeled in the field. Samples contained suspended matters were
removed by filtering through What Mann filter paper number-41.
Analysis of samples were carried out for various water quality parameters
such as pH, electrical conductivity (EC), alkalinity, dissolved oxygen (DO),
biochemical oxygen demand (BOD), Ca, Mg, F -,Cl -, SO4-- and total hardness
(TH) as per standard procedures described- “Standard methods for the examination
of water and waste water, American Public health Association (APHA) 13. The
physical parameter pH was determined using the digital pH meter (model-HI96107
HANNA ITALY), The EC was determined using digital conductivity meter, DO
and BOD were determined using the digital portable analyzer kit, Ca, Mg, and TH
were determined by the EDTA titration method, Chloride content was determined
by
argentometric
titration
method,
Sulphate
content
was
determined
volumetrically, the total alkalinity was determined by using the titration method.
Table -3.01. Sampling Location in Sultanpur City (U.P.):-
S. NO.
SAMPLING SITES
CODE
SOURCES
A- Dug wells
1.
PAYAGIPUR
S1
B- Hand pumps
C- I.M.II Hand pumps
D- Tube wells
A- Dug wells
2.
AMAHAT
S2
B- Hand pumps
C- I.M.II Hand pumps
D- Tube wells
A- Dug wells
3.
SABJIMANDI
CHOWK
S3
B- Hand pumps
C- I.M.II Hand pumps
D- Tube wells
A- Dug wells
4.
GOLAGHAT
S4
B- Hand pumps
C- I.M.II Hand pumps
D- Tube wells
A- Dug wells
5.
LOHRAMAU
S5
B- Hand pumps
C- I.M.II Hand pumps
D- Tube wells
3.04. Sample Programming and Procedures:There are three types of sample collection were carried out in past researches
which can be summarized as follows:3.04.1. Grab Samples: One or two samples collected data at a particular time represent only the
composition of the source at that time and place. Such sources may be represented
by a single grab examples are samples of some surface water and rarely typical
waste water streams.
If a source is known to vary with time, Grab samples collected at suitable
intervals and analyzed separately can document the extant, frequency and duration
of these variations. The changes expected on the basis of sampling interval may
vary from 5 min. to as long as 1 hour or more. Seasonal variation in natural water
system is also possible.
3.04.2. Composite Samples:It refers to a mixture of grab samples collected at the same sampling
locations at different times. A composite sample representing 24 hrs. Period is
considered standard for the most determinations. Analysis of all dissolved gases
residual chlorine, soluble Sulphides, temperature and pH are examples if this type
of determination, Changes in the components as dissolved oxygen. pH or
temperature may produce secondary changes in certain inorganic components such
as Fe, Mn, alkalinity or hardness.
3.04.3. Integrated Samples:For certain purposes, the information required is the best represented by
analyzing mixtures of grab samples collected from different locations. Such
sampling is necessary which is prevalent in the case of a river or stream under
going change in composition across the width and depth. To evaluate average
composition, a mixture of the sample representing various locations is considered.
If combined treatment is proposed for separate waste water system, integrated
samples are considered.
3.05. Collection of Samples:Guidelines of national and international protocols were adapted for sample
collection75. Samples were collected from selected sites after adequate pumping of
the water to purge out the stagnant water from borewells75. .
For physical and chemical examination, the samples were collected in
chemically clean bottles fitted with standard joint stoppers or chemically inert
plastic containers. For sample containing organic materials, use of plastics
container is avoided however fluorinated polymer containing vessels may be used.
Different samples were used for chemical (organic and inorganic) and
bacteriological examinations because of their variations in the methods of
collecting and handling.
3.06. Precautions adopted in collecting the Samples:a. Sampling location is representative of water body.
b. No floating material was permitted to enter the bottle.
c.
The sample was collected at a fixed depth below the surface according
situations.
3.06.1. The relevant factors for sampling programming are:1. Frequency of sample collection.
2. Total number of samples.
3. Size of each sample.
4. Sites of sample collection.
5. Method of sample collection.
6. Transportation and care of samples prior to analysis.
to
3.06.2. Nature of Sample change:Some determinations are more likely than other to be affected by sample
storage before analysis. Certain cautions are subjected to loss by adsorption or ion
exchange with the walls of glass containers these include Al, Cu, Cd, Cr, Fe, Pb,
Mn, Ag, Zn.
Temperature and pH were determined at the site. Different
parameters, volume of the sample required and reagent used for their preservation
are mentioned in table-3.02 and table-3.03:- as mentioned below:Table-3.02:-Preservatives and the types of samples chosen:Preservative
Effect on sample
Nitric Acid
Keeps
Sulphuric
solution
Acid
Bactericide formation carbon Samples containing ammines or
metal
Type of sample employed
in
Metal containing sample
Biodegradable Sample containing organic
of Formalin Sulphate ammonia.
With volatile bases.
Mercuric
chloride
Samples
Bactericide
containing
various
Forms
of
Nitrogen, phosphorous or some biodegradable
organic.
Cooling(40C)
Sample containing microorganism, acidity,
Inhibition of Bacteria, alkalinity, B.O.D., Organic C, P and N colour,
retention of volatile odours.
materials.
Chemical
Reaction
Sample to be analyzed dissolved oxygen
Fix
a
particular using Winkler method.
constituent.
Table-3.03:- Parameters & Preservations: -
Parameters
Minimum
Container
Preservations
pH
100
Polythene
Measured with in 0-hrs
D.O.
100
Polythene
-do-
C.O.D.
500
Polythene
Add H2SO4 to pH-2 and
refrigerated
B.O.D.
1000
Polythene
Refrigerate at 40C
Nitrogen
500
Polythene/glass
Analyzed as soon as possible
Ammonia
Cr, Pb, As,
Add 0.8ml H2SO4/L
500
Polythene/glass
Hg, Zn
Chlorinated
Add 5ml conc. HNO3/L and
refrigerated.
1000
Polythene/glass
Pesticides
Analyze immediately on
same day.
3.07. Water Sample Preservation:Although, there is no possibility of intermixing the samples to each other but
container should be tightly closed to avoid it. Hence various additives and
treatment techniques may be employed to minimize sample deterioration.
3.08. The parameters studied:1. pH
2. Electrical Conductivity (EC)
3. Total alkalinity (TA)
4. Dissolved Oxygen (DO)
5. Biological Oxygen Demand (BOD)
6. Chemical Oxygen Demand (COD)
-
7. Chloride (Cl )
-
8. Fluoride (F )
=
9. Sulphate (SO4 )
10. Sodium (Na)
11. Potassium (K)
12. Calcium (Ca)
13. Magnesium (Mg)
14. Total Hardness (TH)
3.09. PROCEDURE:-Most of the parameters were evaluated using standard
methods for the examination of water and wastewater described in “Standard
methods for the examination of water and waste water, American Public health
Association (APHA).13
3.09.1. pH:pH value is the logarithm of reciprocal of hydrogen ion activity in moles per
liter. In water solution, variations in pH value from 7 are mainly due to hydrolysis
of salts of strong bases and weak acids or vice versa. Dissolved gases such as
carbon di oxide, hydrogen sulphide and ammonia also affect the pH of water. The
overall pH range of natural water is generally between 6 and 8. Industrial wastes
may be strongly acidic or basic and their effect on pH value of receiving water
depends on the buffering capacity of water. pH lower than 4 will produce sour taste
and higher value above 8.5 bitter taste. Higher value of pH hastens the scale
formation in water heating apparatus and reduces the germicidal potential of
chlorine. pH below 6.5 starts corrosion in pipes, thereby releasing toxic metals
such as Zn, Pb, Cd, Cu etc.
Requirements: 1. pH meter:- Model-HI96107 HANNA ITALY,
2. Standard buffers of pH 9.0:- Dissolve 3.81 gm borax (Na2B4O7.10H2O) in
distilled water to 1000 ml.
Theory:-The pH (Potentia Hydrogen ion) of a solution refers to its hydrogen ion
activity and is expressed as the logarithm of the reciprocal of the hydrogen ion
activity at a given temperature.
pH = -log10 [H+]
= log10 [1/H+]
Neutral
Acidic
0
Alkaline
7
14
pH level
Procedure: - pH of water samples chosen were measured using pH meter (modelHI96107 HANNA ITALY) employing standard buffers of pH 9.0 to 4.0 and glass
electrodes.
3.09.2. Electrical Conductivity (EC):Specific conductance yields a measure of water’s capacity to convey an
electric current. Its unit is micromhos/cm or micro Siemns/cmm3. This property
related to the total concentration of the ionized substances in water and the
temperature at which the measurement is made the nature of the various dissolved
substances, their actual and relative concentrations, and the ionic strength of the
water sample vitally affects the specific conductanc
3.09.3. Total alkalinity (TA):-
Alkalinity of water is its quantitative capacity to react with a strong acid to a
designated pH. Highly alkaline waters are usually unpalatable. Excess alkalinity in
water is harmful for irrigation which leads to soil damage and reduce crop yields.
Alkalinity is significant in many uses and treatments of natural and wastewaters.
Alkalinity measurements are used in the interpretation and control of water
treatment processes.
Requirements:A)
Hydrochloric Acid – 0.1 N
0.1N HCl was prepared by dissolving 8.34 ml.of 12N concentrated HCl in
1000 ml.distilled water. 100ml. of this solution was further diluted to 1000ml. This
solution was standardized with 0.1N sodium carbonate solution. (5.3 gm.
previously dried Na2CO3 was dissolved in distilled water for a 4 hours at 25 0 C to
prepare 1 liter).
B)
Methyl Orange Indicator 0.05%:0.5 gm. of methyl orange was dissolved in 100ml. of distilled water.
C)
Phenolphthalein Indicator:0.5 gm. of phenolphthalein was dissolved in 50ml. of 95% ethanol and 50ml.
of distilled water was added to it. 0.05N CO2 free NaOH solution was also
added until the solution turned faintly pink.
Procedure:
i)
100ml. of sample was taken in a conical flask and 2-3 drops of
phenolphthalein indicator were added as a result of which the solution turned
pink.
ii)
The pink solution was then titrated with 0.1N HCl until pink colour
disappears. The amount of HCl used was noted (V1).
iii)
Now 3 drops of methyl orange were added into the same sample and the
titration was continued till the colour change to pink again. The amount of
HCl used was noted (V2).
Calculation:Total alkalinity, carbonate and bicarbonate alkalinity were calculated
with the help of the following formula.
Total alkalinity mg/lit.
=
V2 x N of HCl x 1000
ml. of sample
Carbonate % Alkalinity =
V1 x N of HCl x 1000 x 60
ml. of sample
Bicarbonate % Alkalinity =
(V2 - V1) x N of HCl x 1000 x 61
ml. of sample
Where:
V1
=
amount of HCl used for phenolphthalein titration.
V2
=
Volume of HCl used from phenolphthalein end point to
methyl Orange end point.
3.09.4. Dissolved Oxygen (D.O.):Requirements: - H2SO4, starch indicator, MnSO4, Sodium Thiosuphate.
Theory:-The presence of dissolved oxygen is essential to maintain the efficiency
of biological life and to keep proper balance of various entities making the water
bodies healthy. The main sources of dissolved oxygen are forming the atmosphere
and the photosynthetic process of the green plants. The solubility of oxygen in
water depends upon the partial pressure of oxygen in the air, temperature of water
and mineral content of water. The chemical reactions involved are:
MnSO4 + 2KOH = Mn (OH) 2 +K2SO4
2Mn (OH) 2 + O2 = 2MnO (OH) 2 (Manganese basic oxide)
MnO (OH) 2 + 2H2SO4 = MnSO4 + 3H2O (Manganese Sulphate)
Mn (SO4)2 + 2KI = MnSO4 + K2SO4 + I2
2Na2S2O3 + I2 = Na2S4O6 + 2NaI
Procedure:-Winkler’s modified Iodide azide method was used for the
determination. The Sample was fixed with mangnous suphate (MnSO4) using
alkaline solution of Iodide azide at the site. Water samples were collected in 300ml
capacity bottles. 2ml of manganous sulphate and 2ml of azide reagent was added.
The properly closed were shaken; 2 ml of conc. H2SO4 was added to the
centrifugate. The decanted liquid was titrated with sodium sulphate solution until a
pale straw colour is obtained after which 1-2 ml of starch solution is added and the
titration was continued till the disappearance of blue colour. D.O. was calculated as
follows:
a. Dissolved oxygen (ppm) = Volume in ml of standard hypo used in titration.
b. Total Dissolved Oxygen in terms of ml. of O2 gas at 00C and 760 mm pressure =
dissolved Oxygen (in ppm) x 0.698
c. Solubility of O2 (mg dissolved O2). Its water content is calculated using the
formula (at temperature 30-500C) =
0.827(P-U)
49 + t
Where,
P =
Atmospheric pressure
t =
Temperature (00C)
U =
Saturated Vapour Pressure at t0C
3.09.5. Biochemical Oxygen Demand (BOD): Requirements:-Phosphate buffer solution, MgSO4, NaN3, Conc. H2SO4, FeCl3 etc.
Theory:-The polluted waters are turbid, harmful and unhygienic for various daily
purposes. Micro organisms like bacteria present in the water break down
carbohydrates and release energy.
An estimate if the oxygen consumed in the unit volume of water over a
period of time is called Biochemical Oxygen Demand (BOD).
Procedure:-BOD determination is an empirical test in which standardized
laboratory procedures are used to determine relative oxygen requirements of waste
water, effluents and polluted waters. Two samples were taken separately in BOD
bottles. While one was fixed at room temperature and the other was incubated at
200C in dark for 5 days. The deference in dissolved oxygen in both BOD bottles
represents biochemical oxygen demand. BOD (5 days at 20 0C ) ppm = Initial
dissolved O2 after incubation (ppm)3.09.6. Chemical Oxygen demand (COD):Requirements:-Potassium dichromate, Ferrous Ammonium Sulphate, H2SO4,
AgSO4, HgSO4 Ferroion indicator.
Theory:-Chemical oxygen demand (COD) is the measure of oxygen consumed
during the oxidation of the oxidizable organic matter by a strong oxidizing agent.
The COD values are of great importance where BOD values con not be determined
accurately due to the presence of toxins and other such unfavorable conditions for
growth of micro-organism. The reaction occurring is:K2Cr2O7 + 4H2SO4 = K2SO4 + Cr2(SO4)3.4H2O + 3O
Procedure:-Dichromate reflex method was used to evaluate COD values. The
known volume of water sample was refluxed with a known volume of K2Cr2O7 and
conc. H2SO4 for 2 hours. The amount of dichromate remaining after 3 drops COD
was calculated using the following relation:
COD as O2 (ppm) =
(A-B) x M x 8000
ml. of Sample
Where,
A= ml. FAS used for blanks
B= ml. FAS used for the samples
M= molarity of FAS (moher’s salt)
3.09.7. Chloride (ppm):Chloride is one of the major inorganic anion in water. In potable water, the
salty taste is produced by the chloride concentrations is variable and dependent on
the chemical composition. There is no known evidence that chlorides constitute
any human health hazard. For this reason, chlorides are generally limited to 250
mg/l in supplies intended for public use. In many areas of the world where water
supplies are scarce, sources containing as much as 2000 mg/l are used for domestic
purposes without the development of adverse effect, once the human system
becomes adopted to the water.
High chloride content may harm metallic pipes and structures as well as growing
plants.
Requirement:-
a.
Silver Nitrate:0.02N, 3.4gm. Of Agno3
were dissolved in distilled water to make l liter
solution. The prepared solution was kept in dark bottle.
b.
Potassium Chromate: 5% 5.0 gm. of K2 CrO4 were dissolved in 100 ml. of distilled water to make the
solution.
Procedure:i.
50 ml. of sample which was filtered to whatmann filter paper No.50 using
Buchner funnel.
ii.
50 ml of filtered sample was taken in a 250 ml. conical flask and 2 ml. of
K2CrO4 solution was added to it.
iii.
This solution was then titrated against 0.02N AgNO3 until a persistence red
tinge (colour) appeared. The amount of titrant used was noted (a).
Calculation:Chloride was calculated with the help of the following formula:
a x N (AgNO3) x 35.5 x 1000
Chloride % =
ml.of sample x 23.09.8. Fluoride (ppm):-
Traces of fluorides are present in many waters. Higher concentrations are
often
associated
with
underground
sources.
In
groundwater,
fluoride
concentrations vary with the type of rock that the water flows through but do not
usually exceed 1.0 mg/l. Presence of large amounts of fluoride is associated with
dental and skeletal fluorosis (1.5 mg/l) and inadequate amounts with dental caries
(< 1 mg/l).
Fluoride occurs in all natural water supplies. It may be present in detrimental
concentrations in ground water. Fluorides largely occur in chemical wastes from
industries. Water drawn from subsurface through some geological formations may
also contain high amounts of Fluorides. Fluorides, if present in small
concentrations up to 1 ppm, are generally considered to be beneficial in water.
Such water has been found to improve dental health and prevent the formation of
dental carries. It is found that a Fluoride concentration of slightly greater than 1
ppm in water causes reduction in the cavities of teeth of young children. It also
reduces the decaying and missing teeth. Excessive Fluorides in drinking water may
cause mottling of teeth or dental Fluorosis, which results in discolouration of
enamel, chipping of teeth in children in severe cases. Bone Fluorosis or crippling
effects are observed in case the concentration of Fluorides exceed 1.0 mg/l. the
presence of Fluorides can be determined by adding colouring agent and compare
with standard colouring solutions.
Requirements: - Zirconium-alizarin reagent indicator, Standard solution of NaF,
5N HCl
1. Zirconium-alizarin reagent: - dissolve 0.5 gm of zirconium oxychloride in
pure distilled water in a 100 ml. measuring flask with constant shaking and the
volume is made up to the mark. Prepare another solution of alizarin sodium
monosulphate by dissolving 0.1 gm of it in 100 ml. of pure distilled water. Now
keep the solution in coloured bottle in a cool place. Take 25 ml. of zirconium
oxychloride solution in a beaker and add to it 25 ml of alizarin monosulphate
solution drop by drop with constant shaking. Allow the mixture to stand for
overnight.
Finally dilute the mixture by adding 100 ml. of distilled water and keep the
dilute solution in coloured bottle in a cool place.
2. Standard solution of NaF: - Dissolve 0.2210 gm of NaF in distilled water in a
100 ml.measuring flask and the volume is making up to the mark. Now dilute 5.0
ml. of this solution with distilled water in a 100 ml. measuring flask it now
contains 50 ppm.
Procedure: - Specific Ion Electrode method using the ORION Auto-chemistry
System 740/760 was used for the analysis of fluoride ion in water. Calibration of
instrument was done with appropriate standards using the standard Reference
Material. All the laboratory experimental work was carried out using calibrated
glass wares and apparatus and apparatus.
The Fluoride content in water is determined by using zirconium-alizarin
reagent. Now take the 50 ml. of clear sample in a 50 ml. Nessler tube. Take nine
Nessler tubes of 50 ml. each containing 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4 and 1.6
ml. of the standard NaF solution. Now dilute each Nessler tube with water made up
from salt solution. These standards so prepared 0, 0.2, 0.4, 0.6, 0.8 etc. ppm of
fluoride respectively. Now exactly 5.0 ml. of 5N HCl is added to each Nessler tube
containing the standards and the sample. Mix the solution in each Nessler tube
with a plunger stirrer and then add 1.0 ml. of the zirconium-alizarin indicator to
each Nessler tube and again mix well. Allow the Nessler tube to stand at room
temperature for about a day, mix again and compare.
If fluoride contents are grater than 1.6 ppm, the procedure is repeated with a
sample diluted to 50 ml. with pure distilled water.
3.09.9. Sulphate (ppm):The major physiological effects resulting from the ingestion of large
quantities of sulfate are catharsis, dehydration, and gastrointestinal irritation. Water
containing magnesium sulfate at levels above 600 mg/l acts as a purgative in
humans. The presence of sulfate in drinking water can also result in
a noticeable taste; the lowest taste threshold concentration for sulfate is
approximately 250 mg/l, as the sodium salt. Sulfate may also contribute to the
corrosion of distribution systems.
Sulphate usually occurs in natural waters. Mine drainage wastes also contain
high content of sulphate by virtue of pyrite oxidation. The presence of Na 2SO4 and
MgSO4 in drinking water beyond the prescribed limits may cause cathartic action.
The presence of sulphate may be estimated titrimatically.
Requirement: - HCl, BaCl2 solution, benzedine hydrochloride, phenolphthalein,
N/7 NaOH.
Theory:-The sulphate is precipitated as BaSO4 in acidic medium (by adding HCl)
using BaCl2 solution as the precipitating agent. The precipitation is carried out near
the boiling temperature. After precipitation, the precipitate is digested, filtered and
washed with hot water to remove Cl
-
ions. Finally the precipitate of BaSO4 is
ignited and weighed. All samples of hard water contain dissolved sulphates of Ca
and Mg, in addition to chlorides of these metals. When such a water sample is
treated with an aqueous solution of benzedine hydrochloride, the dissolved sulphte
is precipitated as benzedine sulphate. The precipitate is soluble in hot water to
form sulphuric acid, which can be determined by titration.
Procedure: - Titrimetric method was used for estimation of sulphates in the water
sample.
100 ml. of the water sample was taken in a conical flask and 10 ml. of benzedine
hydrochloride solution (solution of benzedine in dilute HCl containing 4.0 gm of
the diamine base/ liter of the solution) are added. The precipitate formed is filtered
and washed free of acid with minimum amount of distilled water. The precipitate
and filter paper were taken in a conical flask and add 50 ml. of distilled water was
added to it. Now few drops of phenolphthalein were also added. The conical flask
was well shaken to dissolve the precipitate and the solution so obtained is titrated
against N/7 NaOH until pink colour was obtained at the end point.
Calculation:-
Sulphate (as Na2SO4) = No. of ml. of N/7 NaOH x 100
Na2SO4 ppm can be converted into CaSO4 and MgSO4 ppm by multiplying
with a factor of 0.705.
3.09.10. /3.09.11. Na and K (ppm):Theory: - Na and K can be analysed by fame photometry method. The use of a gas
flame as a source of excitation for atomic emission is known as flame photometry.
Fame photometry has been applied to analysis of wide variety of material,
including biological fluids, soils, plant materials, cement, glasses and natural
waters. The quantitative separation and determination of Na and K by wet
chemical test has always been a difficult analytical problem. The examination of
the energy emitted from a substance when suitably excited, is an obvious
instrumental approach for the determination of these elements. It is a well known
fact that a characteristic yellow light is emitted when a small amount of Na is
introduced. Emission of such characteristic radiation by Na or k and the correlation
of the emission intensity with the concentration of the elements form the basis of
flame photometry, which is actually a part of the emission spectroscopy. Because
of low ionization energies of these metals irradiated with light energy absorbed
may be sufficient to make an atom lose an electron. The emitted electron is called
photoelectron and this explains the use of K as cathode in photoelectric cells.
Procedure: - Electron can also be readily excited to a higher energy leveling a
flame too. The heat from the Bunsen burner flame excites one of the orbital
electrons to a higher energy level. When the excited electron comes back to its
original energy level it gives out the extra energy. For Na and K the energy emitted
appears as visible light thus gives the characteristic flame colouration.
In fact the colour arises from electronic transition in short lived species
which are momentarily formed in the flame. The flame is rich in electrons, and in
the case of Na the ions are temporarily reduced to atoms.
Na + + e
Na
The Na D-line, which is actually a doublet to 589.0 nm, arises because
of the electronic transition 3s1
3p1 in Na atoms formed in the flame.
A sodium lamp is used in to detect Na in the sample. Other lamps are used
to detect other elements. In the analysis of water sample, where the determination
of Na and K is required, the interference in the determination of each element by
the other three can be prevented by using radiation buffers e.g. in the determination
of Na, 1.0 ml of a solution i.e. saturated with respect to the chlorides of K, Ca and
Mg is added to a 25 ml of sample. The response of the photometer to the mixed
solution at the sodium wavelength must be compared to a calibration curve
prepared from standards. Another method for preventing the interference is the
method of standard addition, in which a known amount of the desired element is
added to a second aliquot of the unknown, after measurement of the emission from
the unknown and then the measurement is repeated.
3.09.12. Ca (ppm):Calcium is a major constituent of various types of rock. It is one of the most
common constituents present in natural waters ranging from zero to several
hundred milligrams per 100 ml. of water and incrustation in boilers.
Requirement:1.
Ethyl Alcohol 40%
400 ml. of absolute alcohol was mixed with 600 ml. of distilled water to
make 40% ethyl alcohol in a 1000ml. measuring flask.
2.
Ammonium acetate solution
57 ml. of glacial acetic acid was taken in 1 liter measuring flask, diluted to
800ml. of distilled to 800ml. of distilled water and then pH was adjusted to
7.0 with the help of concentrated NH4OH. Final volume of the solution was
made up to 1 liter with the help of distilled water.
3.
Sodium Hydroxide – 0.1N
40gm. of NaOH were dissolved in distilled water in one liter measuring flask
and diluted to make the solution 1 liter.
4.
EDTA Solution 0.01M
3.723gm of Di-sodium salt of EDTA were dissolved in distilled water in a
1000ml. measuring flask to make 1 liter of 0.01M solution.
5.
Murexide indicator
0.2gm. of solid ammonium perpurate was mixed with 1000gm. of NaCl.
6.
Eriochrome Black – T indicator
0.4gm. Eriochrome black – T were mixed with 100gm. NaCl and ground in
a pestle-mortar.
Procedure:-
i
50 ml. of sample was taken in 500 ml. beaker and about 100ml. of 40%
alcohol was added to it. Sample was shaken well and then kept for 15
minutes and filtered through whatmann No.50 Filter paper using Buchner
funnel.
ii
The sample was treated with 100 ml. of ammonium acetate was used to
wash the filter paper and buchner funnel. Then the sample was kept over
night in the laboratory.
iii
Sample was treated with ammonium acetate till the volume was made up to
500ml. (v)
iv
50 ml. of the above sample was taken in a 250ml. conical flask and 2 ml. of
NaOH was added to it (v).
v
200mg. of murexide indicator was added to the solution as a result of which
pink coloured solution was obtained.
vi
The solution was titrated against EDTA till pink color changed to purple.
The amount of titrant used was noted (a).
vii
1 ml. of buffer solution was added to the above solution and 100 mg. of
Eriochrome black – T was mixed. The solution turned wine-red.
viii
The wine – red solution was again titrated with EDTA till the color of winered solution changed to blue. The amount of EDTA used was again noted
(b).
Calculation:Calcium was calculated with the following formula:-
Calcium (ppm).
=
a x 400.8 x V
v x 10 x S
Where:
a
=
volume of EDTA used for murexide indicator
V
=
total volume sample.
v
=
volume of extract titrated.
S
=
weight of soil taken
3.09.13. Mg (ppm):Magnesium is a common constituent in natural water. Magnesium salts are
important contributors to the hardness to the hardness of water which break down
when heated, forming scale in boilers. The magnesium concentration may vary
from zero to several hundred milligrams. Chemical softening, reverse osmosis,
electro dialysis, or ion exchange reduces the magnesium and associated hardness to
acceptable levels.
Requirement:1.
Ethyl Alcohol 40%400 ml. of absolute alcohol was mixed with 600 ml. of distilled water to
make 40% ethyl alcohol in a 1000ml. measuring flask.
2.
Ammonium acetate solution57 ml. of glacial acetic acid was taken in 1 liter measuring flask, diluted to
800ml. of distilled to 800ml. of distilled water and then pH was adjusted to
7.0 with the help of concentrated NH4OH. Final volume of the solution was
made up to 1 liter with the help of distilled water.
3.
Sodium Hydroxide – 0.1N40gm. of NaOH were dissolved in distilled water in one liter measuring flask
and diluted to make the solution 1 liter.
4.
EDTA Solution 0.01M3.723gm of Di-sodium salt of EDTA were dissolved in distilled water in a
1000ml. measuring flask to make 1 liter of 0.01M solution.
5.
Murexide indicator0.2gm. of solid ammonium perpurate was mixed with 1000gm. of NaCl.
6.
Eriochrome Black – T indicator0.4gm. Eriochrome black – T were mixed with 100gm. NaCl and ground in
a pestle-mortar.
Procedure:i
50 ml. of sample was taken in 500 ml. beaker and about 100ml. of 40%
alcohol was added to it. Sample was shaken well and then kept for 15
minutes and filtered through whatmann No.50 Filter paper using Buchner
funnel.
ii
The sample was treated with 100 ml. of ammonium acetate was used to
wash the filter paper and buchner funnel. Then the sample was kept over
night in the laboratory.
iii
Sample was treated with ammonium acetate till the volume was made up to
500ml. (v)
iv
50 ml. of the above sample was taken in a 250ml. conical flask and 2 ml. of
NaOH was added to it (V).
v
200mg. of murexide indicator was added to the solution as a result of which
pink coloured solution was obtained.
vi
The solution was titrated against EDTA till pink color changed to purple.
The amount of titrant used was noted (a).
vii
1 ml. of buffer solution was added to the above solution and 100 mg. of
Eriochrome black – T was mixed. The solution turned wine-red.
viii
The wine – red solution was again titrated with EDTA till the color of winered solution changed to blue. The amount of EDTA used was again noted
(b).
Calculation:Magnesium was calculated with the following formula:-
Magnesium (ppm). =
(b-a) x 400.8 xV
v x 1.645 x 10x S
Where:
a
=
volume of EDTA used for murexide indicator
b
=
volume of EDTA used for Eriochrome black-T.
V
=
total volume sample.
v
=
volume of extract titrated.
S
=
weight of soil taken.
3.09.14. Total Hardness:Hardness of water is caused by the presence of multivalent metallic cations
and is largely due to calcium, Ca++, and magnesium, Mg++ ions. Hardness is
reported in terms of CaCO3. Hardness is the measure of capacity of water to react
with soap, hard water requiring considerably more soap to produce lather. It is not
caused by single substance but by a variety of dissolved polyvalent metallic ions,
predominantly calcium and magnesium cations. The low and high value of
Hardness has advantages and disadvantages absolutely soft water is tasteless. On
the other hand, hardness up to 600 mg/L can be relished if got acclimatized to.
Moderately hard water is preferred to soft water for irrigation purposes. Absolutely
soft water is corrosive and dissolves the metals. More cases of cardiovascular
diseases are reported in soft water areas. Hard water is useful to growth of children
due to presence of calcium.
Requirements: - 0.01 M EDTA solution, buffer solution, Eriochrome black-T
indicator, Sodium Sulphid
Theory:-Hardness is generally imparted by the calcium and magnesium ions
present in water. Polyvalent ions of some other metals like strontium, iron,
Aluminium, Zinc and Manganese etc. are also capable of precipitating the soap and
thus contributing to the hardness. However, the concentration of these ions is very
low in natural waters, therefore, hardness is generally measured as concentration of
only calcium and magnesium (as calcium carbonate), which are far higher in
quantities over other hardness producing ions. Calcium and magnesium form a
complex of wine red colour with eriochrome Black-T and pH of 10±1. The EDTA
has got a stronger affinity towards Ca++ and Mg++ and therefore, by addition of
EDTA, the former complex is broken down and a new complex of blue colour is
formed.
Reagents:1. 0.01 M Ethylene Diamine Tetra Acetic Acid (EDTA) solution-dissolve 3.723 g
of Disodium salt of EDTA in distilled water to prepare 1 liter of solution. Store in
Polyethylene or Pyrex bottle.
2. Buffer solution Dissolve 16.9 g ammonium chloride (NH4Cl) in 143 ml of
concentrated ammonium hydroxide (NH4OH – Ammonia solution).
3. Eriochrome Black-T-Dissolve 0.5g Erichrome black T-Dye in 100 ml of 80%
ethyl
Alcohol.
4. Sodium sulphide solution - dissolve 5 g of Na2S9.H2O (sodium sulphied
nonahydrade) or 3.7 g Na2S3.5H2O in 100 ml distilled water. Tightly close the
bottle to prevent oxidation.
Procedure:-Take 50 ml sample in a conical flask if sample is having higher
calcium , take a smaller volume and dilute to50ml add 1 ml if buffer solution (if
the sample is having higher amount of heavy metals, add 1 ml of sodium sulphide
solution). On addition of 4-5 drops of Eriochrome black-T indicator. The solution
turns wine red. Titrate the contents against EDTA solution at the end point colour
changes from Wine red to blue.
Calculation:Hardness (as mg/1 CaCO3) =
ml EDTA used x 1000
ml.sample
In another method hardness is computed from the result of separate
determination of calcium and magnesium.
Hardness (mg equivalent CaCO3/1)
(2.497 x Ca (mg /1) + (4.118 x Mg (mg/1))
REMOVAL OF FLUORIDE
WATER TREATMENT:- Water treatment is the process of converting raw water
from surface or sub-surface source into a potable form that is suitable for drinking
and other domestic uses (Hofkes, 1981). It also entails the removal of pathogenic
organisms and toxic substances listed earlier, but do not necessarily make the
drinking water pure or sterile in the analytical sense (Oluwande, 1983). The
convection methods by which water is made potable are namely; aeration,
coagulation, flocculation, sedimentation, filtration and other means of disinfection
which make use of physical processes to achieve their objectives.
Fluoride occurs in all natural water supplies. It may be present in detrimental
concentrations in ground waters. Fluorides largely occur in chemical wastes from
industries. Water drawn from surface through some geological formations may
also contain high amounts of fluorides. Fluorides, if present in small concentration
up to 1 ppm, are generally considered to be beneficial in water. Such water has
been found to improve dental health and prevents the formation of dental caries. It
is found that a fluoride concentration of slightly greater than 1 ppm in water causes
reduction in the cavities of teeth of young children. It also reduces the decaying
and missing teeth. Excessive fluoride in drinking water may cause mottling of teeth
or dental fluorosis, which results in discolouration of enamel, chipping of teeth in
children in severe causes. Bone fluorosis or crippling effects are observed in case
the concentration of fluorides exceeds 1.0 mg/L. The presence of fluorides can be
determained by adding colouring agents and comparing with standard colouring
solutions.
The maximum utilized natural resource for all the living beings is “Water”.
Consumption of unsafe water leads to several types of illness, e.g. if excess amount
of fluoride present in water then it is unsafe to take. The excess amount of fluoride
can be removed by defluoridation.
In India people of 196 districts of 19 states are drinking Fluoride
contaminated water above WHO maximum allowed concentration (MAC) of
Fluoride in drinking water of 1.5 mg/L (Goswami et.al.2004) 66.
DEFLUORIDATION OF WATER:In order to reduce excessive fluoride from water, many researchers over the
years have developed wide spectrum of defluoridation technologies like Activated
Alumina based adsorption, Nalgonda ( based on precipitation and flocculation) etc.
Defluoridation based on Activated Alumina (AA), has emerged as a user friendly
technology, which is gaining larger acceptance by community. Activated Alumina
is considered as an excellent sorbent for defluoridation. However, pH and
alkalinity affects the sorption capacity of the sorbets. The following are the main
advantages of Activated Alumina for defluoridation.
 Minimum contact time is needed for maximum defluoridation.
 Attritional loss is minimal even during the regeneration.
 AA can be regenerated up to number of cycles.
 AA is indigenously available and it is cost effective.
 Maximum defluoridation occurs at pH 5.5 but defluoridation capacity at
neutral pH is also appreciable.
 Fluoride uptake is independent of temperature albeit adsorption processes
are considered to be exothermic.
 Effect of ions like Cl-, SO4= and CO3= on defluoridation is minimal.
However presence of HCO3 causes adverse impact on defluoridation.
DOMESTIC DEFLUORIDATION:Domestic Defluoridation units (DDUs) were designed by various
researchers over the years with an aim to treat 20-30 litre of water per day, which
is the average household requirement for drinking and culinary purposes. It
consists of two chambers i.e. upper chamber to accommodate 3-5 kg of alumina
with adequate bed height which is fitted with flow control device optimized at the
flow rate of 8- 10 liters per hour. The lower chamber is meant for collection of the
defluoridated water. Regeneration of exhausted AA is one of the main advantage
of this main advantage of this technique, whereby sorbent can be used in multiple
cycles 58.
Fluoride Uptake Capacity (FUC) of Activated Alumina is largely
dependent upon the bed height and width owing to the following:
 Decrease in the flow rate of water with the increase in the bed height Due to
resistance caused by the sorbent bed.
 Reduction in the contact time of solute at the solid and liquid interface if bed
height is decreased.
 Optimized bed height provides optimum flow rate for adequate contact.
Keeping in view of the above, any change in shape and design must be
corroborated with adequate research and technical data with regard to FUC.
Specifications of activated alumina:-
Activated Alumina is a porous material with the comprised mainly of
active sites. It is prepared by dehydration of Al (OH) 3 in the temperature range of
300-6000C. By means of thermal treatment, eta, gamma and chi alumina phases are
formed. It is an amphoteric substance and its isoelectric point is approximately pH
9.5. Aluminium with positive trivalent charge strongly attracts electronegative
fluoride ion. Activated Alumina for defluoridation purposes should comply with
the requirements of IS 9700-1991 (Grade 1).
In addition to the above specifications, the AA should also meet the following
requirements as outlined in the draft specifications of IIT- Kanpur developed on
the basis of their research work.
 The grain size shall be 0.4-1.0 mm (mechanical grinding not acceptable).
The yield of treated water(fluoride<1.5mg/lit) will be> 170 l/kg of AA per
cycle when raw water having alkalinity 420 mg/l, pH 7.3 and flu8oride
10.5+0.5 mg/l is passed through a 3 kg AA- bed with flow rate 9-12 litre per
hour.
 Under these standard conditions the fluoride uptake capacity shall not be less
than 1800 mg/kg of AA. The manufacturer should also specify the fluoride
uptake capacity. Fluoride uptake capacity after ten regenerations, loss of
attrition in each regeneration cycle and residual aluminum in treated water
due to leaching, if any (preferably treated water should be free from residual
aluminum).
 AA should be washed thoroughly with water to remove dust particles and
dried, AA should not impart residual aluminum to treated water.
Grain size as prescribed in the specification is optimum to provide appropriate pore
volume and adequate surface area, which are the most significant conditions for
achieving desired FUC by adsorption. Smaller particles will provide more
resistance and hence slow down the flow rate, while larger parities will increase
the porosity and hence reduce the optimum pH of raw water for defluoridation is
5.5-8.0. Hence very high alkalinity of raw water will reduce the affinity of fluoride
ion towards the AA sorbent.
Regeneration of activated alumina:In order to sustain the defluoridation by activated alumina regeneration of
exhausted AA is required by treating it with NaOH 1%, subsequent washing
with raw water. This is followed by H2SO4 0.4% treatment and washing with
raw water to neutral pH. Regeneration is one of the main advantage of
Activated of Alumina technique, whereby sorbent can be used in multiple
cycles.
Regeneration facilities at the village level should have adequacy in terms of
following major components 6.
 Infrastructural Adequacy.
 Technological Effectiveness.
 Technical Competency for the operator.
 Procedural Appropriateness.
 Effective Documentation.
 Compliance to Safety/ environment Aspects.