Controlling factors in water Chemistry

V.Subramanian

School of Envt.Sc,JNU

and

Institute of Envt.Sc,Amity university

subra42@gmail.com

Solar eruptions

Solar eclipse, gauhati. Sept

26,2012.

Human Body : Water NeedsHuman Body : Water Needs

80% 75% 70%

Fetus / Embryo New Born Adult

Brain 85%

Inactive

Adult

Active Adult

Loss

2 lit./day

Needs

2 lit./day

Needs

3 lit./day

Water Content

Water Distribution in Human Body

13%

15%

15%

16%

13%

15%

13%Brain

Lungs

Kidney

Blood

Heart

Liver

Muscles

Daily water loss

Human Body : Daily Water LossHuman Body : Daily Water Loss

Sole of Sole of

FeetFeetBreathingBreathing PerspirationPerspiration UrineUrine

250 ml250 ml 900 ml900 ml 450 ml450 ml 1300 ml1300 ml

Our personal water balance Water loss

Skin – 550 cc. Lungs – 440 cc. Urine – 1550 cc. Stool – 2650 cc. Total – 2650 cc.

Water Intake

Liquids – 1500 cc. Solid foods – 750 cc.

Produced in the body – 400 cc. Total – 2650 cc.

Water Chemistry

Weathering

Rock Type Hydro Factors

Climate

Rainfall

Regional Scale

Soil Cover

Local / Regional Variability

Episodic / Regular Events

Major Parameter

Nutrients

Metals

Secondary

Anthropogenic Land use Change

Urban inputs

Industrial

Resources Exploitation

Common Linkage

Fractionation

Estuary Ocean

River Behavior

Meanders

Delta Formation

Cut-offs

Flood and Sediments

First order impacts

• Sediment transport

• Water quality & temperature

• Transfer of energy

• Pollutants

Second order impacts

• Channel geomorphology

• Primary production

• Channel structure

Third order impacts

• Fish and invertebrate communities

• Spawning / scouring in water courses

Ecological Flow

River Behavior and Impacts

Factors Controlling dissolved parameters in water

1. Input = Output Steady state

Stable gradient Residence time Constant

Example: Cl-

2. Input > Output Non-steady state

Accumulation Residence time Higher,

Example: Hg+

3. Input < Output Non-steady state

Depletion/Erosion Residence time Lower,

Example: Rare gases?

4. Episodic Input/Output Prolonged non-equilibrium

Residual Dis-equilibrium in both Imbalance in residence time

Chemical (quality) and physical Example: Landslide/Volcanic

(quantity) processes Eruptions

Three phases of water

Water and Air interaction

• H2O(l) + CO2(g) = H2CO3(l)

• 1/[PCO2] k= 10(-3.5)

• H2CO3 = HCO3- + H+

• [HCO3-] [H+] / [H2CO3] k=5.(10-7)

• HCO3- = CO3-2 + H+

• [CO3-2] [H+] / [HCO3-] k=5.(10-11)

• HOH(l) + HOH(l) = H3O+ + OH-

• [H3O+] [OH-] k= 10(-1)

• HHO= H+ + OH-

• [H+]. [OH-] k=10 (-14)

Size-charge of elements

Radius-charge for ions in water( based on

Pauling)

Physical factors in Water Chemistry

• 1.Temperature

• 2.Pressure

• 3.Flocculation

• 4.Particle Size effect

• 5.Reaction Time

• 6.Turbulance/Flow velocity

• 7.Density

• 8.Dilution-concentration

Density-Temperature plot for

water

Unusual saline ground water in

Turkey

Float in Dead Sea !

•

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Chemical factors in water chemistry

• Dissolution

• Precipitation

• Complexation

• Colloids

• Oxidation-reduction

• Chelation

• Dilution

• Pollution

• Absorption-Desorption

Dissolved and solid carbon in

water

Basic rock-water reaction

2CO2 + 3H2O + CaSiO3 → Ca++ + 2HCO3- + H4SiO4,

Where, Ca++ might also be substituted by Mg++,

Fe+2,Zn+2 etc

CO2 + H2O + CaCO3 → Ca++ + 2HCO3-

or

2CO2 + 2H2O + CaMg(CO3)2 → Ca++ + Mg++ + 4HCO3-

Solubility factors

• Radical Soslubility

• Nitrates (NO3-),chlorides All nitrates and

chlorides are soluble

• Sulphates (SO4-2) Many sulphates are soluble.

• ------------------------------------------------------------------

• Carbonates (CO3-2) All carbonates are insoluble.

• Hydroxides (OH-) All hydroxides are insoluble.

• Sulphides (S-2, HS-1) All sulphides are insoluble.

1:1

0.1

1

10

0.1 1.0 10.0

Alkalinity meq/L

(Ca

+M

g)

me

q/L

Himalyan Rivers

Peninsular Rivers

Correlation of Alkalinity against total Ca

+ Mg

100 1000 10000 Alkalinity micro.eq/l

Kerala Rivers

Other Rivers

G-B river system

Saturation line 10000

1000

100

Carbonate saturation in river water

Tota

l dis

solv

ed s

olid

s

Na / (Na + Ca)

Gibbs diagram of water chemistry

Godavari river- CO2 plot

MB- Main branch; TR– Tributaries; CW- CO2 consumption rate due to

chemical weathering; SW- CO2 consumption rate due to silicate weathering

Atm and Soil derived alkalinity in

rivers

Basin Area vs pCO2

0

500000

1000000

1500000

2000000

G-B-M

I (P)G (I)

B I (L)G K M N C T W

FRs

River Basins

Bas

in A

rea

(km

2)

-4.00

-3.00

-2.00

-1.00

0.00

1.00

pC

O2 (

mE

q/L

)

Basin Area

pCO2

CO2 consumption rates (106 mol km-2 y-1) in

Silicate weathering for major world rivers

0.00

0.50

1.00

1.50

2.00

2.50

Narmada

TaptiMeckong

Ganges

Brahmaputra

Mississippi

Amazon

Mackenzie

St Lawrence

Lena

River Basins

CO

2 (

sil)

r water chemistry of India

Ganges river water

Average ground water chemistry in

India ( mg/l)

Lake water in India

Calculated HCO3 for various pCO2

scenario

y = 1.0029x - 1.6215

R2 = 0.9949

-4.5

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

-3 -2 -1 0 1 2

Log m HCO3,m/l

Lo

g p

CO

2,a

tm

Long term impact on water quality?

pCO2 and Deforestation

?

CO

2 c

on

sum

ed

in W

eat

he

rin

g

Deforestationincreasing

increa

sing

Model indicating the inter

Water,Society and Global change and Socirty and health and healthynergies between the concerns

Quality depends on quantity

also

Now, let us look into some

issues on water quantitatively

since quality and quantity are

inseparable!

Framework for Analysis of the Fresh

Water Environment

Drivers for monsoon rain

• El Nino is an oscillation of the ocean-

atmosphere system in the tropical Pacific

having important consequences for weather

around the globe.

• La Nina is the name for the cold phase of

ENSO, during which the cold pool in the

eastern Pacific intensifies and the trade winds

strength.

0

200

400

600

800

1000

1200

1400

1600

Delhi Kolkata Shillong Chennai Trivandrum Mumbai

Delhi

Kolkata

Shillong

Chennai

Trivandrum

Mumbai

Tota

l R

F (

mm

)

Monsoon, 2012 ( 1 June- 30 September)

The unpredictable rain!

•

Monsoon rainfall

Monsoon 2013 till sept 10

•

•

Virtual water demand

• 1 kg wheat 1500 litres

• Daily drinking water we need 2.5 litres

• 1 Kg rice 3000-5000 litres

• 1 Kg banana 2000 litres

1Kg of meat 15000 litres

Example of virtual water

Product Unit of measurement water consumption in liter

tomato 1 piece 13

Al metal can 1 piece 25

tea 1 cup 35

potato chips 1 bag (200 g) 185

paper 1 kg 750

bananas 1 kg 2000

cotton shirt 1 piece 2000

egg 1 kg 4500

rice 1 kg 5000

jeans 1 piece 8000

computer 1 piece 30000

car 1 piece 380000

Source of ganges waterSource of

Source of Ganges waterGanges

water

Water use through centuries

0

50

100

150

200

250

300

1900 1940 1950 1960 1970 1980 1990 1995 2000

(Year)

Irri

ga

ted

Are

a (

Millio

n H

a)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Wa

ter

us

e (

Km

3/y

r)

Irrigated Area Water Use

Water for agriculture

Water use for Major Crops in Asia

(Average production rates)

0

200

400

600

800

1000

1200

Cott

on

Pea

nut

Bar

ley

Bea

ns

Whea

t

Corn

Pota

to

Gra

in S

org

hum

Sunfl

ow

er

Tom

atoes

Sugar

bee

ts

Sugar

cane

Ric

e

Crop

Wat

er U

se(m

m)

Water for irrigation- from where?

Urban water demand

Per Capita Water Supply in Selected Metros

208

258

227

76

114

242

200

307

207

170156

262253

274

0

50

100

150

200

250

300

350

Mu

mb

ai

De

lhi

Ca

lcu

tta

Ch

en

na

i

Ba

ng

alo

re

Hy

de

rad

ab

ad

Ah

me

da

ba

d

Ka

np

ur

Na

gp

ur

Pu

ne

Ja

ipu

r

Lu

ck

no

w

Ka

rac

hi

Ba

ng

ko

k

City

Lit

re/ d

ay

Mumbai 2005: 2000 mm in 24 hrs

Endowments of water infrastructure…..

US and Australia have ~5000 m3/cap;

China has 2,400;

India has 130 m3/cap

India

130

Water and energy

Water for Energy Generation and

industry

Petroleum extraction. 10-40 litre/Mwh

Gas power plant 30000-75000

Coal gasification 900

Coal power plant 23000 litre/Mwh

Nuclear power plant 94600-227100

Biofuel power plant upto 27900000 litre/Mwh

Dams in Tibet

Water in air

Water from air !

Water droplets on mars lander

Artificial recharge of water

Artificial Recharge of water

Achankoil

Pamba

150x106 m3 Tunnel - 9 km

Vaipar River Basin LINK PROJECT

MICRO SCALE

Ken-Betwa Link?

Water resources development-

case from M.P.

Super Link!

Parameter units Bramaputra

Cauvery

Area (mill.ha) 53 2

Cultivated,(mil.km2) 18 10

Water needed( mill.ha.m) 3.6 2

Man and animal :all need water in

some form- virtual or real !