Transcript Chulli Water Purifier - Harvard University Department of Physics

Chulli Water Purifier
Professor M. Fakhrul Islam
Dept. of Applied Chemistry & Chemical
Technology , Rajshahi University
Bangladesh
Back Information
A. Arsenic contaminated tube wells : Almost
25% of the total installed.
B. Almost lower half of the country arsenic
affected.
C. No. of people at risk : 30 million or more.
People have already developed arsenicosis
symptoms drinking the arsenic tainted water
A.
Suggested Mitigation Options
Surface water use.
I.
II.
Rain water storage in concrete tanks.
Pond , river water and large water bodies : use of sand
filtration.
III. Dug well.
These are all in effect rainwater use , but may be variously
contaminated by suspended particles dissolved impurities and
bacteria
B. Deep aquifer water use : Deep tube well based piped water
system
Arsenic filters
Each has its merits and demerits from different considerations
discussed as pointed out by many. Not used widely .
Other Possible Systems
 Bacteria filters for surface water.
 Thermal treatment of surface water after filtration.
 Sunlight and UV radiation treatment of surface water.
 Chemical treatment of surface water (chlorination etc)
These are physico –chemical and chemical processes, excepting
the thermal treatment i.e boiling of water, none are practiced in
villages for different reasons
Boiling Surface water produce very safe bacteria free water but
high cost due to high fuel cost
Cooking - Energy Sources in Bangladesh
Village : wood and dried plant materials & cow dung.
Small towns: Mostly wood but some gas.
Big towns: Cities in Eastern part gas; but in Western
part no gas, use bottled gas or wood.
Gas reserve: To last for another 5-6 years only if no
big reserve discovered now.
Coal: may be used in future in towns and villages
Energy position is bleak and may be same in villages and even for
towns in the future. Cost increase and availability to decrease
with time .
Boiling of extra water for producing safe drinking water will
decrease forest area and also gas reserve very fast.
THE CHULLI CONCEPT
a.
b.
c.
d.
Bangladesh mud chulli used every where
Chulli wastes enormous heat energy (>80% ,BCSIR)
Villagers cook 2-3 times daily
Waste heat use will save much energy and ultimately
environment .
e. Chulli temperature high inside
Alternative to Boiling
Water passed through a small dia. coiled pipe inside
chulli heated to 70* or more very quickly, Bacteria killed
very fast
Suggested Mechanism of pasteurization
by heat treatment in coiled pipe
A. Very high turbulence due to heat and flow.
B. Many repeated contact of bacteria with hot
surface (Brownian movement and turbulence).
C. Rapid heat transfer for large surface area
compared to boiling in pot.
The following slides show the principal aspects of
chulli water purifier
Chulli Water Purifier
Diagrammatic
A Practical Chulli Water Purifier
Water Flow in Hot Pipe
Chulli Water Purifier Data
Coil size
10” dia
Pipe 4
turns
Chulli
dimension
1- 1/2 feet
Deep, 10”
dia.
Operation
time
Rice
cooking
time
approximat
ely 40
minutes
Temperature
of water
collection
Amount of
water
produced
average
30 Liters+
70- 76*C
Bacteria Test Data
Total coliform counts /100 ml in water
Run
1
2
3
Initial in Pond water
1750
2500
560000
after pass through chulla
0
0
0
N.B Analysis for other chemical water parameters not done,
but assumed to be within safe limits as generally found.
Field Test


Till now almost 3000 chulli water purifier units
installed in >11 upozillas of different districts
affected with arsenic in tube wells with
assistance from UNICEF by a local NGO .
Field test data match the experimental chulli
purifier data .
Very highly bacteria contaminated water can be
treated.
Almost all types of water from pond ,river and
baor can be made bacteria free.
Clean water obtained.

Social acceptability varies place to place



Conclusion
1.
2.
3.
4.
5.
6.
Water pasteurization at no extra fuel cost.
Extremely easy to set and operate.
Large amount of bacteria free safe water
produced by a single chulli for 2-3 families.
Very low cost (Tk 450 for the whole unit).
All components locally available.
Principle applicable to other large waste heat
generators such as rice mills ,brick kilns after
thorough technical research for volume
production of water from surface waters in
the arsenic affected and non affected areas.
THANK YOU