water resources water quality till feb 22 (1)

8/3/2019 Water Resources Water Quality Till Feb 22 (1)

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WATER RESOURCES AND

WATER QUALITY

PARAMETERS

Tayyab Ashfaq

Institute of environmental engineering &Research(IEER)

UET Lahore


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Lakes and river water useable=95200km3

Total

water on

earth=1386

X106km3


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SOME OF THE GLOOMYARITHMETIC

OF WATER 1.4 billion people lack safe water

80% of diseases carried by water: 1 child every 8seconds killed and 5-7 million people annually: $125billion in workday losses/yr.

50% of people lack adequate sanitation

20% of freshwater species near extinction

76% live in water stressed areas most in politicallyunstable regions

Past 30 yrs world water supply has halved

Losing irrigated land by 30% in 2025 and 50% by2050

Asia: Over two thirds of population live in areaswhere 80% of rainfall occurs in 20% of the year

Next 30years 5.5 billion safe water supply difficult

"There is a water crisis today. But the crisis is not about having too

little water to satisfy our needs. It is a crisis of managing water so

badly that billions of people - and the environment - suffer badly."

World Water Vision Report


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CONSUMPTION PATTERN OF WATER


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Energy Type Water Consumed

(m3/MWh)

Solar 0.001

Wind 0.001

Gas 1

Coal 2

Nuclear 3

Oil/Petrol 4

Hydropower 68

Bio-fuel 239

Water Footprints for energy


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WATER RESOURCES OF PAKISTANRainfall Annual rainfall (125mm in South-East to 750mm North-West) Total water generated by rainfall is around

32 BCM Contribution to crops is 10-20%

Groundwater Exploitation of Groundwater is 59 BCM Over 9,00,000 private tubewells

Surface Water Resources Total Inflow is 171 BCM Tarbela (10.38 BCM - 485 ft), Mangla (5.90 BCM - 380 ft) 48 Canals (61000 km), 19 Barrages 1,70,000 Watercourses (1.6 Million km)


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FRESHWATER AVAILABILITY SCENARIO (PER PERSON)

Global

1950 16,800 cubic meters per annum


Reduction: 60 % in 50 years

Pakistan


2000 1,200 cubic meters per annum !!!!

Reduction: 77 % in 50 years

Critical limit 1,000 cubic meters per person per annum


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FUTURE WATER SCENARIOYear Population Water availability

(Million) per capita (m3)

1951 34 5300

1961 46 39501971 65 2700

1981 84 2100

1991 115 1600

2000 148 1200

2010 168 1066

2020 196 915

2025 209 850


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EXISTING SITUATION

Surface water largest source of irrigation inPakistan (31% as a single source)

79% access to piped /hand pump water supply 30% of diseases 40% deaths water borne

90% exposed to unsafe drinking water

BOD Ravi=300mg/l(9mg/l)


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Physicalparameters

Taste&odour

Turbidity

Conductivity

Total dissolved solids

Color

Chemicalparameters

Alkalinity

pH

Hardness

Metals andnonmetals

Bacteriologicalparameters

Bacteria

Virus

Protozo

a

Helminth

Radiologicalparameters

-Activity

-Activity

WATER QUALITYPARAMETERS

Quality :degree of excellence, a measure of fitness of use

Drinking water quality: degree of cleanliness andwholesomeness of water


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PHYSIC AL PARAMETERS

Organics, Biologicalactivity, industrialpollution

Inorganic compoundsof metals like sodium,copper, iron and zinc

Organic

matter(humic),metals(iron,

manganese) or highly

coloured industrial

waste

Taste & odour Colour


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TURBIDITY

Optical property

Caused by suspended matter(clay, organics,

microorganism)

High level turbidity shield and protectbacteria from the action of disinfecting

agents

Nephelometer turbidity unit

Desirable limit-5NTUshould be below 1 NTU when disinfection

is practiced

Permissible limit-10NTU


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TOT AL DISSOLVED SOLIDS

Inorganic salts and few organics

Time of year, local geological conditions, climate,waste discharges

Aesthetic standards

TDS(mg/l)

Brackish water 1000-5000

Saline water 5000-30000

Seawater 30000-35000

Rivers & lakes


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Conductivity

Measure of electrolyte content/TDS

Units: siemens/cm or mho/cm

TDS(mg/l)=kxEC (mho/cm) (k=0.5-0.9;0.64)


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CHEMIC AL PARAMETERS

It is the measure of hydrogen ion concentration

Desirable limit 6.5-8.5 Factors: bed-rock, acid rain, wastewater

discharge

pH


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DEFINITIONS OF

PH

pH stands for powerof Hydrogen

pH is a value thatrepresents the how

acidic a solution is. pH is the negative

log of thehydroniumconcentration. (pH =

-log [H3O+]) pH calculations are

used to determinethe exponent of thehydronium (H3O

+)concentration


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CONCENTRATION & PH

The pH and the exponent are the sameAs pH increases by 1.0, the hydronium

concentration decreases by 10


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PH ILLUSTRATION

Beaker # 1 Beaker # 2 Beaker # 3

pH = 1.0 pH = 2.0 pH = 3.0

[1 x 10-1] [1 x 10-2] [1 x 10-3]

1/10 1/100

NOTE: [ ] means mol/L


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CALCULATING PH

Determine the pH of a sample of rainwater that has ahydronium-ion concentration, [H3O

+(aq)], of 1.00 x 10

-4 mol/L.

pH=-log10[H3O+

(aq)] = -log10[1.00x 10-4]

= 4.000

Calculate the hydronium-ion concentration, [H3O+

(aq)]

in a shampoo with a pH of 5.72.

[H3O+

(aq)] = 10-pH= 10 -5.72

= 1.905x 10-6 mol/L = 1.9 x 10-6 mol/L


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sample [H3O]+ pH

Rainwater 1.00x 10-4

Shampoo 5.72

HCl 0.5

Acetic acid 1.31x 10-3

Soil solution 4.7

Determine the missing values


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sample [H3O]+ pH

Rainwater 1.00x 10-4 4

Shampoo 1.9 x 10-6 5.72

HCl 0.5 0.3

Acetic acid 0.0013 2.89

Soil solution 2 x 10-5 4.7

Determine the missing values


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CHEMICAL PARAMTERS :HARDNESS

Salts of polyvalent cations(Ca,Mg,Fe,Mn,Al,Cu,Ba,Zn,Pb)

Scale formation, prevents lather(500mg/l)

Temprary hardness.Ca/Mg(HCO3)2

H2O(l) + CO2(g) + CaCO3(s) Ca(HCO3)2(aq)

H2O(l) + CO2(g) + MgCO3(s) Mg(HCO3)2(aq)

Permanent hardness-Cl-1,NO3

-1, SO4

-2

aq. + CaSO4(s) Ca2+(aq) + SO4

2-(aq)

aq. + MgSO4(s) Mg2+(aq) + SO4

2-(aq)


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Problem 1

A sample of water on analysis gave the following

results:CaCO3= 2.5 g/l,MgSO4= 1 g/l,CaSO4= 0.5

g/l,MgCl2= 0.25 g/l,Fe2O3= 0.01 g/l, SiO2= 0.25g/l

Calculate the total hardness in g/l


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PROBLEM 1

A sample of water on analysis gave the following

results:CaCO3= 2.5 g/l,MgSO4= 1 g/l,CaSO4= 0.5

g/l,MgCl2= 0.25 g/l,Fe2O3= 0.01 g/l, SiO2= 0.25

g/l

Calculate the total hardness in g/l

Total hardness=3.96g/l

Hardness Amount(g/l)

MF Eq of CaCO3

CaCO3 2.5 100/100 2.5

MgSO4 1 100/120 0.83

CaSO4 0.5 100/136 0.37

MgCl2 0.25 100/95 0.26


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PROBLEM 2

Calculate the temporary hardness and total

hardness of water in mg/l

Hardness Amount(mg/l)

MF Eq of CaCO3

Ca(HCO3)2 16.2

Mg(HCO3)2 7.3

CaSO4 13.6

MgCl2 9.5

H=1,C=12,O=16, N=14, Mg = 24, K = 39, Cl=35.3, Ca= 40,S=32


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PROBLEM 2

Calculate the temporary hardness and total

hardness of water in mg/l

Hardness Amount(mg/l)

MF Eq of CaCO3

Ca(HCO3)2 16.2 100/162 10

Mg(HCO3)2 7.3 100/146 5

CaSO4 13.6 100/136 10

MgCl2 9.5 100/95 10

H=1,C=12,O=16, N=14, Mg = 24, K = 39, Cl=35.3, Ca= 40,S=32


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PROBLEM 3

Hardness Amount

(mg/l)

Molecular

mass(g/mol)

MF Eq of CaCO3

Ca(HCO3)2 26.4

Mg(HCO3)

2

13.8

CaSO4 15.5

MgSO4 6.5

MgCl2 20

CaCl2 15

Calculate the temporary hardness permanent

hardness and total hardness of water in mg/l


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PROBLEM 3

Hardness Amount

(mg/l)

Molecular

mass

(g/mol)

MF Eq of CaCO3

Ca(HCO3)2 26.4 162 100/162 16.3

Mg(HCO3)

2

13.8 146 100/146 9.45

CaSO4 15.5 136 100/136 11.4

MgSO4 6.5 120 100/120 5.42

MgCl2 20 95 100/95 21.05

CaCl2 15 111 100/111 13.51

Calculate the temporary hardness permanent

hardness and total hardness of water in mg/lTemporary hardness=25.75 mg/l ; Permanent hardness=51.36 mg/l


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ALKALINITY

Capacity to neutralize acid Presence of carbonates, bi-carbonates and hydroxide

compounds of Ca, Mg, Na and K

Alkalinity = hardness, Ca and Mg salts

Freshwater =30-130mg/l as CaCO3


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METALS & NON-METALS

Earths most plentiful resource(35%mass)

High iron causes brown or yellowstaining of laundry, household fixtures

Metalic taste, offensive odour Cause iron bacteria

Acceptable limit 0.3 mg / l

Iron


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METALS & NON-METALS

Ground water fromarseniferous belt

Industrial waste,agricultural insecticide

Effects : dermatologicallesions, muscularweakness, paralysis oflower limbs, can also

cause skin and lungcancer

Acceptable limit 0.05mg / l

Present as mineral in soil

and rocks of earth

Human activities

Battery Lead &

Nickel

Textile - Copper

Photography Silver

As Heavy metals


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METALS & NON-METALS

Dissolution of salt

deposit

Discharge of effluents

Intrusion of sea water

Not harmful to human

beings

Regarding irrigation most troublesome anion

Acceptable limit - 250

mg/l

Agricultural

fertilizers, manure,

animal dung,

nitrogenous material

,sewage pollution

blue baby disease to

infants Maximum permissible

limit 50 mg / l

Chlorides Nitrates


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FLOURIDEOccurs naturallyLong term consumption above

permissible level can cause dentalflurosis (mottling of teeth)

-Skeletal flurosis

Maximum permissible limit 1.5 mg / lRemedy 1) Deflouridation

2) Mixing Fluoride free water3) Intake of vitamin C,D,

calcium


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MICROORGANISMS

Virus:obligate parasites, 0.01 and 0.03 m

Bacteria: single cell (spherical,rod shaped or

spiral) 0.1 to 15 m-pipe corrosion, taste & odour)

Protozoa: unicellular, nonphotsynthetic, aerobic;2-200m

Helminths :parasitic worms

Source:water ,vegetables

Control:filtration,coagulation


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BACTERIOLOGICAL PARAMETERS

Total Coliforms-nonpathogenic,genito-urinarytract infection

Ferment lactose with gas formation at 35OC

Faecal coliform thermotolerant , sustain at44.5OC

Aerobactor aerogenes

Soil ,plants, grains sometimes in faeces

Escherichia Coli(E.coli)

Intestinal tract warm blooded animals


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RADIOLOGIC AL ACTIVITY

Disintegration of unstable nuclei

Alpha emission

Beta emission Alpha and beta activity

Natural radionuclides (uranium thorium) in soil

1 Becquerel =1 radioactive decay/second

Gross activity=0.1Bq/l; Gross activity=1Bq/l

water resources water quality till feb 22 (1)

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