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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
There are 3 kinds of water:-drinking water-waste water-surface water
Drinking water or potable water is water of sufficiently high quality that can be consumed or used without risk of immediate or long term harm. It is provided by water supply networks or may be found in deep wells or springs.
Waste water or sewage comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations. In the most common usage, it refers to the municipal wastewater that contains a broad spectrum of contaminants resulting from the mixing of wastewaters from different sources.
Surface water is water collecting on the ground or in a stream, river, lake, wetland, or ocean; it is related to water collecting as groundwater or atmospheric water.
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Regulations
Waste water
Law: HG 352/2005, completion of HG 188/2002 refers to 2 types of waste water:
-industrial and urban waste waters overflowed into natural receivers (lakes, rivers) (NTPA 001)
-waste waters overflowed into sewerage networks (NTPA 002)
Environmental Protection Law 137/1995 updated by
Ordonance 195/2005
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MEASUREMENT OF POLLUTANTS IN WATERWaste water quality standard NTPA 001 (several chemical indicators)
No. Quality indicator Unit Limit values Analysis method
1. pH pH units 6,5-8,5 SR ISO 10523-97
2. Suspended materials mg/dm3 35,0 (60,0) STAS 6953-81
3. Biochemical Oxygen Demand at 5 days
mg O2/dm3 25,0 SR EN 1899-2/2002
4. Chemical Oxygen Demand (CCOCr) mg O2/dm3 125,0 SR ISO 6060-96
5. Ammonia (NH4+)6) mg/dm3 2,0(3,0) SR ISO 5664:2001
SR ISO 7150-1/2001
6. Nitrates (NO3-)6) mg/dm3 25,0(37,0) SR ISO 7890-2:2000;
SR ISO 7890-3:2000
7. Sulphide (S2-) mg/dm3 0,5 SR ISO 10530-97
8. Phenols (C6H5OH) mg/dm3 0,3 SR ISO 6439:2001;SR ISO 8165/1/00
9. Oil products mg/dm3 5,0 SR 7877/1-95
10. Total phosphorus (P)6) mg/dm3 1,0(2,0) SR EN 1189-2000
11. Synthetic detergents mg/dm3 0,5 SR EN 903:2003
12. Aluminium (Al3+) mg/dm3 5,0 STAS 9411-83
13. Calcium (Ca2+) mg/dm3 300,0 STAS 3662-90SR ISO 7980-97
14. Lead (Pb2+)3) mg/dm3 0,2 STAS 8637-79;
15. Nickel (Ni2+)3) mg/dm3 0,5 SR ISO 8288:2001
16. Zinc (Zn2+)3) mg/dm3 0,5 STAS 8314-87
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MEASUREMENT OF POLLUTANTS IN WATERWaste water quality standard NTPA 002 (several chemical indicators)
No. Quality indicator Unit Limit values Analysis method
1. pH pH units 6,5-8,5 SR ISO 10523-97
2. Suspended materials mg/dm3 350,0 (60,0) STAS 6953-81
3. Biochemical Oxygen Demand at 5 days
mg O2/dm3 300,0 SR EN 1899-2/2002
4. Chemical Oxygen Demand (CCOCr) mg O2/dm3 500,0 SR ISO 6060-96
5. Ammonia (NH4+)6) mg/dm3 30,0 SR ISO 5664:2001
SR ISO 7150-1/2001
6. Cyanide total (CN) mg/dm3 1,0 SR ISO 6703/1-98-2/00
7. Sulphide (S2-) mg/dm3 1,0 SR ISO 10530-97
8. Phenols (C6H5OH) mg/dm3 30,0 SR ISO 6439:2001;SR ISO 8165/1/00
9. Oil products mg/dm3 5,0 SR 7877/1-95
10. Total phosphorus (P)6) mg/dm3 5,0 SR EN 1189-2000
11. Synthetic detergents mg/dm3 25 SR EN 903:2003
12. Cadmium (Cd-) mg/dm3 0,3 SR EN ISO 5961:2002
13. Zinc (Zn2+) mg/dm3 1,0 STAS 8314-87;SR ISO 8288:2001
14. Lead (Pb2+)3) mg/dm3 0,5 STAS 8637-79;
15. Nickel (Ni2+)3) mg/dm3 1,0 SR ISO 8288:2001
16. Manganese (Mn) mg/dm3 2,0 SR 8662/1-96
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Regulations
Drinking water
Law 311/2004, completion of Law 458/2002
ParameterLimit value(number/100 ml)
Escherichia coli (E.coli) 0
Enterococi 0
Microbiological parameters
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Drinking waterLaw 311/2004, completion of Law 458/2002
Chemical parameters
Parameter Limit value Unit
Ammonia 0,50 mg/l
Chlorine 250 mg/l
Conductivity 2.500 S cm-1 la 200C
Nitrate 50 mg/l
Nitrite 0.5 mg/l
pH > 6,5; < 9,5 unităţi de pH
Sulphate 250 mg/l
Sulphyde 100 g/l
Turbidity < 5 UNT
Chromium total 50 g/l
Zinc 5.000 g/l
Iron 200 g/l
Manganese 50 g/l
Copper 0.1 mg/l
Alpha global activity 0,1 Bq/l
Beta global activity 1 Bq/l
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Drinking water – USA National Primary D.W. regulations
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Drinking water – USA National Primary D.W. regulations
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Surface waterLaw Order 1146/10.12.2002
Chemical parametersParameter Unit Limit values
I II III IV
pH pH units 6,5 < pH < 8,5
Dissolved oxygen mg/l O2 7 6 5 4
BOD5 mg/l O2 3 5 10 25
CODCr mg/l O2 10 25 50 125
Nitrate mg N/l 1 3 6 15
Nitrite mg N/l 0.01 0.06 0.12 0.3
Total phosphorus mg/l 0.1 0.2 0.4 1
Zinc total g/l background 100 200 500
Chromium total g/l background 2 4 10
Nickel total g/l background 50 100 250
Lead total g/l background 5 10 25
Copper total g/l background 20 40 100
Anionic detergents g/l background 500 750 1000
Oil hydrocarbures g/l background 100 200 500
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
How to measure all of these parameters?
There are various methods, techniques and equipments devoted to measure water quality parameters.
They are divided in:
- in-situ methods
- laboratory methods
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Environmental monitoring
Measurement of water pollutants using ion selective electrodes (ISE)
Ion selective electrodes
(video clip)
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Environmental monitoring
Measurement of water pollutants using ion selective electrodes (ISE)
Ions to be measured using ISE
CationsAmmonium (NH4+) Barium (Ba2+) Calcium (Ca2+) Copper (Cu2+)
Lead (Pb2+) Mercury (Hg2+)Potassium (K+)Sodium (Na+)Silver (Ag+)
AnionsBromide (Br-)Chloride (Cl-)Cyanide (CN-), Fluoride (F-)Iodide (I-)Nitrate (NO3
-)Nitrite (NO2)Perchlorate (ClO4
-)Sulphide (S-)
Thiocyanate (SCN).
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Environmental monitoring
Measurement of water pollutants using ion selective electrodes (ISE)
Advantages of measuring using ISE
• very fast and easy measurements• the possibility of implementation of continuous monitoring• relatively inexpensive• wide range of concentration for a large variety of ions• by fulfilling the imposed conditions of maintenance and calibration, one
can achieve accuracy and precision levels of 2 – 3 %, sometimes comparable with analytical techniques.
• unaffected by sample colour and turbidity.
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Environmental monitoring
Measurement of water pollutants using ion selective electrodes (ISE)
Measurement principle of ISE (example pH measurement)
Measurement electrode
Reference electrode
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Environmental monitoring
Measurement of water pollutants using ion selective electrodes (ISE)
Measurement and reference electrodes
Glass bodyMeasurement
electrode
Bulb filled with potassium chloride
buffer solution
Voltage produced across thickness of
glass membrane
Very thin glass bulb chemically doped with lithium ions
Wire connection
Measurement electrode Glass body
Bulb filled with potassium chloride
buffer solution
Voltage produced across thickness of
glass membrane
Very thin glass bulb chemically doped with lithium ions
Wire connection
Reference electrode
Wire connection
Filled with potassium chloride
buffer solution
Porous junction
Glass or plastic body
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Environmental monitoring
Measurement of water pollutants using ion selective electrodes (ISE)
Nernst equation
anF
RTEE lg
303,20
a = activity of ions (for pH, a is the activity of hydrogen ions)
C = ion concentration
γ = activity coefficient
E = measured potential
E0 = standard electrode potential (E for a = 1)
R = gas constant
T = absolute temperature [K]
F = Faraday constant
n = ion charge (n = 1 for pH)
apH lgCa
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Environmental monitoring
Measurement of water pollutants using ion selective electrodes (ISE)
nF
RTslope
303,225 oC
50 oC
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Environmental monitoring
Measurement of water pollutants using ion selective electrodes (ISE)
KCl
shieldedcable
reference electode (Ag/AgCl)
junction glass frit
measurement electode (Ag/AgCl)
membrane
referencefilling hole
reference junction
filling hole
Combined (double junction) electrode
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Environmental monitoring
Measurement of water pollutants using ion selective field effect transistors (ISFET)
Principle of operation of an ISFET
Source
Substrate
InsulatorSensitive layerDrain
Gate
p-type Si
VGS
G
D
S ID
VDS
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Environmental monitoring
Measurement of water pollutants using ion selective field effect transistors (ISFET)
Some ISFET Characteristics
Analyte Sensing structure Comments
Ammonium
PVC treated with HMDS for adhesion
Sensitivity: 30mV/part NH4
Detection limit: 2x10-6
Both sensor and reference fabricated FET
Cd2+, Pb2+ Polysiloxane + cyclodextrin Sensitivity: 29 mV/decade for Cd2+
Sensitivity: 15 mV/decade for Pb2+
Lifetime: 3 months
Cu2+ Etched chalcogenide glass with aluminium adhesion layer
Sensitivity: 28 mV/part CuResponse time: 5 sLifetime: several weeks
Cyanide PVP (poly-(4-vinylpyridine-co-styrene) with horseradish peroxidase as sensitive layer
Sensitivity: 10-7 to 10-5 molar solutionReproducibility: 20 % (pH dependent)
K+ Polysiloxane with poly-HEMA adhesion layer as sensitive layer
Sensitivity: 59 mV/decadeLifetime: 75 days
Na+ Polysiloxane Sensitivity: 56.7 mV/decade
pH Tin oxide Sensitivity: 58 mV/pHLinear between pH 2 to 10Response time: 1 s
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATEROptical methods
They are based on:
-reflection
-colorimetry
-absorbtion of light
-fluorescence
E = hc/λ = hν
Fluorescence
This method utilizes the fluorescence, either natural or induced, of a compound. Fluorescent chemicals absorb radiation of a specific wavelength and emit at another.
Monochrome light
ν0 ν1
Light detector
Sample
Planck equation
h = Planck’s constant (6.626 ·10-34 J·s)
C = velocity of light in vacuum
λ = wave length
ν = light frequency
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATEROptical methods
Nephelometry
White light or infrared light
White light or infrared light
Light detectors
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATEROptical methods
Colorimetry
A = log(I/Io) = knC
Visual tests
Monochrome light
I0 I
Light detector
Sample
Photometer
Beer’s law
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Colorimetry
Water Quality Colorimeter
(video clip)
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Environmental monitoring
Measurement of water parameters using UV-VIS spectrophotometer method
The measurements may be performed in laboratory or in the field
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Environmental monitoring
Measurement of water parameters using UV-VIS spectrophotometer method
Spectrophotometer DR 2800
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Environmental monitoring
Measurement of water parameters using UV-VIS spectrophotometer method
Spectrophotometer DR 5000
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Environmental monitoring
Measurement of water parameters using UV-VIS spectrophotometer method
Cuvette tests method
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Environmental monitoring
Measurement of water parameters using UV-VIS spectrophotometer method
Parameters to be measured
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Environmental monitoring
Measurement of water parameters using UV-VIS spectrophotometer method
Hach robot for spectrophotometric measurements
(video clip)
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATERMeasurement of metals using Atomic Absorption Spectrophotometry (AAS)
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
Beer – Lambert’s law
lcl
I
IT 1010
0
T = transmission (transmissivity)
α = absorbtion coefficient
l = pass length (distance the light travels through the material
ε = molar absorptivity of the absorber
c = concentration of the absorber in the material
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
Difference between atomic and molecular spectroscopy
Atomic spectroscopy Molecular spectroscopy
- concerns only the properties of atoms - concerns the molecules, which are infinitely more numerous
- concerns all the interaction of electromagnetic waves
- we can found the nature and the amounts of a given element in the sample
- gives us more advice than atomic spectroscopy especially about chemical functions and structure of matter
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
Analytik Jena Zeenit A700 AAS spectrophotometer
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
AAS Block Diagram
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
Flames used in AAS
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
Light source
Hollow cathode lamp
Xenon lamp
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
Detection limits for some elements (μg/l)
Element Flame Electrothermal (furnace)
Ag 3 0.02
Al 30 0.2
Ca 1 0.5
Cd 1 0.02
Cr 4 0.06
Cu 2 0.1
Fe 6 0.5
Mn 2 0.02
Ni 3 1
Pb 5 0.2
Sn 15 10
Zn 1 0.04
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Dissolved Oxygen (DO) Measurement
There are three methods:•Azide-Winkler method•Metering with DO probe•Field kits
Dissolved oxygen analysis can be used to determine: • the health or cleanliness of a lake or stream, • the amount and type of biomass a freshwater system can support, • the amount of decomposition occurring in the lake or stream.
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Dissolved Oxygen (DO) Measurement (Winkler method)
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Dissolved Oxygen (DO) Measurement with Clark electrodes
Clark type electrode
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Influence of the temperature upon Dissolved Oxygen
curve A – fresh water
curve B – salted water
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Biochemical Oxygen Demand (BOD)
• BOD is a measure of the oxygen used by microorganisms to decompose the organic waste dissolved in water.
• BOD is affected by temperature.• BOD is influenced by the content of nitrates and
phosphates dissolved in the water.• BOD is an indicator of the organic quality of water.• It is most commonly expressed in milligrams of oxygen
consumed per litre of sample during 5 days of incubation at 20 C.
Two methods of measurement:- Dilution method- Manometric method
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Biochemical Oxygen Demand (BOD)
BOD Level(in ppm)
Water Quality
1 - 2Very GoodThere will not be much organic waste present in the water supply.
3 - 5 Fair: Moderately Clean
6 - 9
Poor: Somewhat PollutedUsually indicates organic matter is present and bacteria are decomposing this waste.
100 or greater
Very Poor: Very PollutedContains organic waste.
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Biochemical Oxygen Demand (BOD)
Dilution method
BOD can be calculated by:
Undiluted: Initial DO - Final DO = BOD
Diluted: (Initial DO Final DO) x Dilution Factor
A very small amount of micro-organism seed is added to each sample being tested
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Biochemical Oxygen Demand (BOD)
Manometric method
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATERBiochemical Oxygen Demand (BOD)
Working procedure
Required apparatus:BOD bottlesSpatula scoopBOD incubatorSeal cup, stir bar
Reagents2 potassium hydroxide pellets
Recommended