Report submitted on GANESH IDOL DISINTEGRATION Contributors

1

Report submitted on

GANESH IDOL DISINTEGRATION

By

Authors

Dr. Shubhangi B. Umbarkar*, Tanushree C. Kane, Savita S.

Pophale

Contributors

CSIR-NCL

Dr. Shubhangi B. Umbarkar, Ms. Tanushree Kane, Ms. Savita

Pophale

CUMMINS INDIA

Subramaniam Ravichandran, Amit S. Lele, Niranjan V.

Painarkar, Vidya Kulkarni, Hemant Deshpande, Chetan K.

Shende

MOJJ ENGINEERING SYSTEMS LTD

Dr. M. K .Dongare, Mr. B. B Pol, Mr. Dhiren Oak

2

TABLE OF CONTENT

1) Introduction 3

2) Objective 10

3) Experimental Setup 11

4) Experimental results 13

5) Pros and cons of the experiment 27

6) Precautions 28

7) Summery 28

8) Recommendations 29

PUNE MUNICIPLE CORPORATION

Mr. Suresh Jagtap, Ms. Ketki Ghatge

DESCRIPTION

This report documents the optimization of various

experimental parameters for disintegration of POP idols

of Ganesh, observations and recommendations for its

practical implementation.

3

4

GANESH IDOL DISINTEGRATION

1. Introduction

Shree Ganesh festival, one of the most popular festivals in India is

celebrated in the states of Maharashtra, Tamilnadu, Karnataka, Andhra Pradesh

and other states. Especially it is Maharashtrian tradition to worship shree Ganesh

during Ganesh chaturthi to Anant chaturdashi for ten days. The duration of the

worship varies from 1.5 day upto ten days in different communities. After festival

the idols are immersed in the sea or in river. Traditionally the idols were sculpted

out of clay (shadu) for worship and after the festival it was returned to the earth

by immersing in water which gets disintegrated automatically and the same clay

can be reused next year. However in recent years due to considerable increase in

the demand for more idols as well as bigger idols, plaster of paris (POP) is being

used for Ganesh idols preparation. The size of household Ganesh idols varies

from 1.5 to 2 feet (~2 - 10 kg) whereas the idols which are worshiped in common

(sarvajanik) may range from 5 to 15 feet. In few cases the size may be as large as

25-30 feet in height.

This cycle was meant to represent the cycle of creation and disintegration

in nature. Due to unavailability and fragility of clay idol now day’s Plaster of

Paris (POP) is being used largely to make idols especially bigger idols due to the

strength and stability of POP. POP is not a naturally occurring material and

contains gypsum, sulphur, phosphorus and magnesium. The POP idols do not

dissolve in water and after immersion remains as such in the water and pollutes

lake, ponds, rives and sea. The chemical paint used to decorate the Ganesh idol

contain mercury, lead, cadmium and carbon and this increases the acidity and

heavy metal content in the water. Careless dumping of Ganesh idols in water

bodies blocks the natural flow of water and also disturbs the aquatic life. This

results in stagnation and breeding of mosquitoes and other harmful pests. The

polluted water causes several diseases including skin diseases. Hence there is a

need of a technique which can completely disintegrate the POP idols and make

the process eco friendly.

Idol immersion results reflect the cumulative effect of POP, clay, chemical

colors and other materials; there is no way to ascertain the exact role of POP in

water pollution as well as its larger impact on the environment. When an idol

5

made of POP is immersed in the water, there is no chemical change in the idol

Adding a large amount of material to the water adds to the hardness of water,

which deteriorate the life carrying capacity and quality of the water thereby

causing irreversible environmental effects on the coastal ecology or the eco-

system of any water body, which in turn causes adverse environmental effects.

Effect of POP idol immersion on environment:

1) The immediate and most observable impact of POP idol immersion is that it

makes the water cloudy.

2) Non-biodegradable idols can block the natural flow of water bodies, allowing

stagnation. 3) Gypsum being natural material does not discount the fact that adding large

quantities of it to water will raise its hardness and reduce its life-carrying

capacity.

4) The idol immersion in river water show several significant impacts like steep rise

in concentration of heavy metals, dissolved solids, and acid content, and a drop in

dissolved oxygen. It is studied by testing the water quality before and after idol

immersion.

5) In Pune, most of the immersions take place at the confluence of the Mula and

Mutha rivers, and it is common experience that the floating idols later get stuck

in waterworks installations, intake wells and so on.

6) The paints used for decorating the idols are of different types as water paints,

fluorescent colors, water leaker like warnish & polish.

7) In terms of health impacts, paints are a greater source of hazard and most of those

used for decorating idols are chemical-based. They contain heavy metals like

mercury, cadmium and lead, which are neurotoxin (nerve poison) and

nephrotoxin (poison to kidneys).

8) These metals are bio-accumulative, meaning that once they enter marine life

forms like fish; they pass through the food chain and end up in the food that we

eat. Incidentally, the brighter the color, the greater is its toxicity. Red, blue,

orange and green colors are known to have higher content of mercury, zinc

oxide, chromium and lead.

9) The safe levels of these chemicals in natural environment are reported in

literature in the unit of ppb - parts per billion, which is 1000th part of 1 milligram

per liter of water. Sometimes the permissible levels of these toxic metals are

reported as one millionth part of a milligram in one liter of water i.e. ppt.

Therefore, this implies that -one drop in a 20-acre lake can make the fish

poisonous to the birds, animals, and people that eat them.

6

10) The only paints that work on POP are oil paints which are high in poisonous

chemicals and heavy metals. The impact of these colours can be heavy. Studies

on before and after immersion water quality show a disturbing rise in

concentration of hazardous heavy metals like lead, mercury and cadmium post

immersion.

11) The study conducted by Central Pollution Control Board (CPCB) revealed that

after immersion, acid content and dissolved solid content in the water rose

significantly. Presence of heavy metals like iron increased 10 times, while the

presence of copper in sediments increased by 200 to 300 times.

12) Study of change in concentration before, during & after idol immersion in Sharyu

River revealed the following facts:

13)

Sr.

No

Parameter Before

immersion

During

immersion

After

immersion

1 DO (mg/ L) 15 10 11

2 BOD (mg/ L) 9 14 11

3 Total hardness (mg/

L)

35 41 50

4 Turbidity (NTU) 30 60 55

5 Ca (mg / L ) 38.14 51.57 60.93

6 Mg (mg/ L) 8.78 11.58 15.75

7 Cd (mg/ L) 0.003 0.012 0.031

8 Mn (mg/ L) 0.091 0.181 0.299

9 Pb (mg/ L) 0.192 0.219 0.411

10 Fe (mg/L) 0.123 0.311 0.521

11 Hg ( mg/ L) 0.575 0.617 0.811

14) The various immersed along with the idols and its impact on environment

is given below:

Sr.No Material contributed during

immersion Impact on the aquatic body

1 Plaster of Paris Increases dissolved solids, contribute to

metals and sludge

2

Decoration material viz.

clothes, polish, paint,

ornaments cosmetic items etc.

Contributes suspended matters, trace metals

(Zinc, lead, iron, chromium, arsenic, mercury

etc.) metalloids and various organic and

inorganic matter, oil & grease etc.

3 Flowers, Garlands, oily Increase floating suspended matter organic

7

substance contamination, oil & grease and various

organic and inorganic matter.

4 Bamboo sticks, Beauty

articles

Big pieces get collected and recycled while

small pieces remain floating in water or

settled at the river bottom inhabiting river

flow.

5 Polythene bags/plastic items Adds to the hazardous material and chokes

the aquatic life

6 Eatables, food items etc. Contributes oil and grease, organics to water

bodies.

1.1 Plaster of Paris (POP)

The chemical formula for Plaster of Paris is CaSO4·½H2O. POP is

produced by heating the mineral gypsum (CaSO4·2H2O). Large deposits of

gypsum were originally found outside of Paris in France hence it was named as

Plaster of Paris. When gypsum is heated to about 150°C it losses water and

produces POP. The difference in gypsum and POP is only water of crystallization.

When water is added to the POP powder, it rehydrates (absorbs water) and

quickly hardens.

Heat

8

2CaSO4·2H2O 2CaSO4·½H2O

+ 3H2O

(Gypsum) (POP)

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

2500

3000

3500

4000

Intensity(a.u)

2θθθθ

XRD Image of POP (CaSO4)

1.2 Uses of Plaster of Paris

It is used in the construction industry either as a building material or

limestone aggregate for road building.

It is also used in hospitals to give support for the bones injured during the

accidents.

Plaster of Paris is used to make slab decorations.

Statues that used for the decoration are made up of POP because of its

strength and its hardness with water.

9

There are many environmental issues related to POP idol immersion in

river water as discussed in effects.

The origins of Ganesh Chaturthi started with the agrarian community

bringing home a mould of soil from the river bank, worshipping it and then

immersing it back to the river after the ritual. This ritual was to pay respect to

earth and also to signify the cycle of creation and dissolution, acknowledging

the fact that all things come from nature and go seamlessly back to it. Instead of

looking at immersion from a ritualistic point of view, we need to understand the

thought behind it. Today knowing the harmful chemicals in the idols as well as

colors, we need to make practical adjustments in the immersion practices. It is

today’s need to use either ecofriendly Ganesh idols or the ecofriendly way of

immersion.

The green immersion is of two types as 1) Artificial immersion and 2)

Symbolic immersion.

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1) Artificial Immersion:

Idols immersed in the limited amount

of water in the tank so that all the water

in river will not get polluted. The idols

then accumulate at the base of the

artificial pond.

2) Symbolic immersion :

Instead of the actual Ganesh idol we

could immerse a betel nut and pack

away the idol for use the next year.

Another way of immersion could be

sprinkling a few drops of water on the

idol and then wiping it off and keeping

the idol for another year to use. In case

of metal idols we can immerse the idol

in a tub or a bucket at home & can be

withdrawn after

In artificial immersion method we are trying to do some development for

disintegration of POP idols as much as possible. By using different salts we are

trying to disintegrate the Ganesh idols. The chemicals tried are as Bicarbonate &

carbonate salts.

Solutions:

1) It is the worlds need to celebrate “ Green” gansh festival i. e it should be

ecofriendly

2) Either Ganesh idol can be ecofriendly made up of Clay (Shadu in Marathi)

or made up of paper mache.

3) If both of above is not possible then atleast the way of immersion should

be ecofrienly so that the POP idol will disintegrate.

1.3 Recycling of POP

11

On the large scale POP is simply crushed in the crusher machine to the

fine powder and reused for any application.

1.4 Challenges in Ganesh idol recycling

The recycling of the Ganesh idol made up of POP by conventional

crushing is not possible due to the sentimental attachment of people with the

Lord. Hence to avoid the water and soil pollution related to POP idol immersion,

the project was taken up for development of the new technique for disintegration

of POP idols which will be more environmental friendly and acceptable by

general public. The Ganesh idol is made up of POP and is confirmed by X-ray

diffraction analysis as shown below:

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

2500

3000

3500

4000

Intensity(a.u)

2θθθθ

XRD analysis of

Ganesh idol

12

Preamble

Cummins India as part of the Corporate Social Responsibility (SCR)

activity was working with Pune Municipal Corporation on eco-friendly ways of

disintegrating POP Idols especially Ganesh idols. Cummins Research and

Technology India Ltd. (CRTI) team had attempted to dissolve POP idol in

aqueous solution of baking soda. Initial experiments carried out by CRTI team

with POP idols demonstrated the feasibility of this method for its utility for

dissolving Ganesh idols. The process took long time and left behind residue

which had to be characterised. However CRTI team could not optimise the

amount of baking soda, water and time required for disintegration of POP as well

as analysis of the solid residue, which was needed for its further use, hence CRTI

team approached CSIR-NCL (Drs. Dongare and Umbarkar) for help in this work.

NCL agreed to carry out optimisation of the various parameters like amount of

baking soda needed for disintegration of POP idol and chemical analysis of the

residue formed.

Initially NCL reproduced the experiment with baking soda (sodium

bicarbonate) and found that disintegration takes longer time due to low solubility

of baking soda in water. Hence it was decided to screen different carbonate salts

like sodium carbonate, potassium carbonate with higher solubility in water and

study the disintegration of the idols.To minimise the time required for

disintegration, the following objectives were set for the project:

2. Objectives

1) To identify a suitable chemical agent for disintegration of the Ganesh POP

idols.

2) To study the effect of different parameters on extent of disintegration and

time required for disintegration of POP idols.

3) Study the kinetics of disintegration of POP idols under optimized

conditions.

4) Detailed chemical analysis of the residue formed to evaluate its utility in

various applications.

13

5) Detailed chemical analysis of the aqueous phase and to evaluate the

recovery of solids from aqueous phase or its utility as aqueous solution.

6) Check the purity of the residue and suggest possible utilization of the

same.

2.1 Optimization

Cummins Research and Technology India Ltd. (CRTI) team had attempted

to dissolve POP idol in aqueous solution of baking soda. Initial experiments

carried out by CRTI team with POP idols demonstrated the feasibility of this

method for its utility for dissolving Ganesh idols. However the process took long

time so this method was ruled out.

In NCL the various experiments were carried out for the disintegration of

POP idols on the lab scale. Initially the experiments were carried out using

various salts like sodium bicarbonate (NaHCO3), sodium carbonate (Na2CO3),

potassium carbonate (K2CO3), ammonium carbonate ((NH4)2CO3) and ammonium

bicarbonate (NH4HCO3). The solubility of all the salts was determined and the

disintegration of small POP idols was carried out using the solution of above

mentioned salts to compare the time of disintegration. To minimise the

disintegration time various parameters likes stirring, heating, shaking, sonication,

water jet and spray were studied and optimised.

Different carbonates are used through out the experiment for

disintegration of POP idol. Sulphates reaction with carbonate is well known acid

base reaction. In the literature there are many reports on reaction of calcium

sulphate with carbonates leading to formation of calcium carbonate. Calcium

sulphate (POP) does not react with other salts like nitrate, chloride etc as these

salts are also acidic. Reaction of calcium sulfate with carbonate salt will generate

insoluble calcium carbonate which can be used in various applications and water

soluble sulfate salts which will be separated easily from solid calcium carbonate.

14

3. Experimental Setup

3.1 Lab scale experimental setup

Brief description of the various experimental techniques used for the

optimization is given below:

Heating: On lab scale experiments

1 lit glass beaker containing salt

solution was used in which the

idol was immersed. The beaker

was heated using hot plate with

temperature controller for

controlling the heating and

maintaining constant temperature.

Whereas for larger scale 200 lit

plastic drum was used and the

water was heated using domestic

immersible water heater (as shown

in the picture).

Stirring: Overhead stirrer (as

shown in the picture ) was used for

small scale in beaker (1 lit) and for

larger scale in 200 lit plastic drum

for stirring only the solution above

the idol so as to have uniform

concentration of the salts though

out the solution during

disintegration.

15

Sonication: The beaker (500

ml) containing carbonate solution

and idol was kept in sonicator (230

volts, 50 Hz, 3.5 lit capacity). It

was not possible to take trial on

large scale in sonicator.

Shaking & heating: The

beaker (500 ml) containing

solution and idol was kept on

laboratory shaker with shaking

speed in the range of 100 rpm.

This could was not possible on

larger scale in NCL

Water jet and spray: On

larger scale in 200 lit plastic

drum a Tullu pump was used to

spray the water on the idol

either from the top or from

bottom of the idol as idols are

hollow from inside. For this

experiment the idol was kept

on the mesh above the water

level and salt solution was

circulated using Tullu pump

from bottom of the idol or

using a spray (shower) from

top

16

The results of representative experiments carried out for optimization of

various parameters on small idols (~50 g) and actual ganesh idols (5-10 kg) are

given below:

4 Experimental Results

Effect of solubility

Solubility of different carbonate salts to be used for the experiment is given in the

table 1.

Table 1: Solubility of different salts in water

Sr. No Chemical Common name Water solubility

(g/Lit) at 20 ºC

1 NaHCO3 Sodium bicarbonate (Baking Soda) 96

2 Na2CO3 Sodium Carbonate(Washing Soda) 215

3 K2CO3 Potassium Carbonate(Potash) 112

4 (NH4)HCO3 Ammonium Bicarbonate (Powdered

baking Ammonia)

216

Effect of different salts on disintegration of POP

To identify the suitable salt for disintegration of POP idol, initial

experiments were carried out using small idols of ~50 g and the observations

are given below (table 2).

Table 2: Effect of Different salts on POP disintegration

Sr. Salt Charge Observation

17

No.

1 NaHCO3 Water 200 ml + Salt (63 g) +

Idol (62g)

50 % disintegration in 6 hrs, no

complete disintegration even after

73 hrs

2 Na2CO3 Water 200 mL + Salt (51 g) +

Idol (50 g)

65 % disintegration in 5 hrs and

complete disintegration in 23 hrs

3 K2CO3 Water 200 ml + Salt (61 g) +

Idol (60 g)

30 hrs for complete disintegration

4 (NH4)HCO3 Water 200 ml + Salt (54 g) +

Idol (54 g)

complete disintegration in 21 hrs

After the initial experiments (table 2) it was observed that NaHCO3 and

K2CO3 have less solubility in water and hence needs longer time to dissolve the

salt in water. Also during the disintegration experiment the rate of disintegration

was very slow in NaHCO3 and K2CO3. Hence further experiments were carried

out using Na2CO3.

The effect of temperature on rate of disintegration was studied using Na2CO3 in

the temperature range of 40 - 80 °C. The rate of POP disintegrations was found to

be faster at higher temperature. The effect of stirring/shaking as well as sonication

on rate of disintegration was also studied. The disintegration was considerably

faster when stirring or shaking was used. Sonication also enhanced the rate of

disintegration significantly. The results for effect of different parameters on rate

of disintegration are summarized in table 3.

Effect of various parameters on POP disintegration

Table 3: Effect of different parameters on POP disintegration using Na2CO3

Sr.

No.

Temp. Water Weight of

Na2CO3

Weight of Idols Observations

1 Room

Temperature

500 mL 100 g 110 g Complete disintegration

in 27 hrs

2 Room 4 lit 854 g 499 g Complete disintegration

18

Temperature in 27 hrs

3 60 °C 500 mL 100 g 117 g Complete disintegration

in 12 hrs

4 80 °C 1 lit 200 g 219 g Complete disintegration

in 4.5 hrs

5 80 °C 4 lit 850 g 852 g Complete disintegration

in 10 hrs

6 80 °C 11 lit 2.3 kg 2.3 kg Complete disintegration

in 8 hrs

Advantages and disadvantages of Methods Used

It was difficult to maintain the uniform temperature throughout the

charge as the heavy residue is formed during the disintegration which

settles at the bottom. The heating was done using hot plate and the

settled heavy residue was getting heated more and the heat was not

decapitated to the solution uniformly hence the temperature of the

solution was lower.

Uniform and continuous heating the solution may not be feasible and

economical on large scale.

The effect of heating on rate of disintegration was studied on

slightly bigger scale with 2.3 kg idols and the observations are given

below (table 4). Also the extent of disintegration was monitored with time

and the results are given in the table 5 below:

Table 4: Effect of temperature on disintegration on larger scale

Weight of

idols

Water Weight of

Na2CO3

Observation

2.3 Kg 11 Lit

2.3 Kg When heated at 60-80 ºC,

complete disintegration in

8 hrs

19

Table 5: Observation Table

Sr. No Time (hrs) Observation (% disintegration)

1 0 Rapid bubbling started

2 1 20

3 3 70

4 4 75

5 5 80

6 6 85

7 8 90

The experiment

showed that heating at

higher temperatures

increases the rate of

disintegration.

However heating the

solution uniformly at

constant temperature

may not be feasible and

economical at large

scale.

Effect of Temperature and Shaking

The combined effect of heating and shaking/stirring (shaker at 65 °C at

100 RPM) on the rate of disintegration was studied and the observations are given

bellow:

0 1 2 3 4 5 6 7 8 910

20

30

40

50

60

70

80

90

100

Dis

inte

gra

tio

n(%

)

Time(hr)

20


Sr. No Time (hrs) Observation (% disintegration)

1 0 Disintegration started with bubbling

2 2 80

3 3 85

4 4 90

5 5 95

6 6 Complete disintegration

2 3 4 5 6

80

85

90

95

100

Dis

inte

gra

tio

n(%

)

Time(hr)

The results showed

substantial increase

in the rate of

disintegration when

heating as well as

stirring was used.

Effect of Sonication:

To study if sonication enhances the rate of disintegration, the idol was

sonicated in sodium carbonate solution and the observations are given below:

Table 7: Experimental condition

Weight of idols Water Weight of

Na2CO3

Observations

21

54 g 250 mL 54 g 95 % disintegration in 4

hrs


Sr.No Time

(hrs)

Observations

(% disintegration)

1 0 Disintegration started with bubbling

2 1 25

3 3 85

4 4 95

1.0 1.5 2.0 2.5 3.0 3.5 4.0

20

30

40

50

60

70

80

90

100

Disintegration(%)

Time(hr)

Sonication has improved

the rate of disintegration

compared to all other

techniques like stirring

and heating however it

may not be feasible and

economical on

Scale up studies (with Big Idols)

After optimizing the parameters with small idols the experiment was carried

out on actual Ganesh idols and the observations are given below:

Table 9: Experimental Condition

22

Weight of idols Water Weight of

Na2CO3

Observations

4.9 Kg 40 Lit 7 Kg 80% disintegration was observed in 9

hrs with intermittent heating using

immersible household heater

Here the ratio of sodium carbonate salt and POP was not kept constant as

before (1:1 wt equivalent) as excess solution (20% salt solution) had to be added

to immerse the idol completely. The idol used for this experiment had coconut

shell husk (used for support) which came out during the experiment.

0 2 4 6 8 10

20

30

40

50

60

70

80

Dis

inte

gra

tion

(%)

Time(hr)

The experiment carried out with actual ganesh idol showed almost

80% disintegration in 9 hrs but later the rate was very slow and

complete disintegration was for possible even after further 24 hrs.

During this experiment it was observed that the idol was hollow

from inside with opening at the bottom. Also the idol had plastic

paint which peeled off slowly with time. Due to which there was no

direct contact between sodium carbonate and POP. Till the paint

peeled off the disintegration was mainly from the hollow opening

and only after the paint was peeled off, the disintegration of idol

started from outside as well.

23

4.1 Chemistry behind the disintegration

The reaction of POP with sodium carbonate takes place as follows:

Na2CO3 + CaSO4 CaCO3 + Na2SO4

During the disintegration the calcium sulphate (POP) reacts with sodium

carbonate and calcium carbonate is formed as heavy residue which settles down

and sodium sulphate is formed which is soluble in water. The pH of the solution

becomes highly alkaline (pH 11-12) because of the dissolved sodium sulphate.

The residue of the reaction was characterized by X-ray diffraction analysis and

was confirmed to be calcium carbonate (Figure below). As calcium carbonate

formed is very fine powder and forms sludge in which the remaining idol gets

embedded and hence the reaction becomes very slow after some time. Due to this

limitation, stirring of the solution was essential and overhead stirrer was used in

subsequent experiments.

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

2500

3000

3500

4000

Intensity(a.u)

2θθθθ

POP(Calcium Sulfate)

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

2500

Intensity(a.u)

2θθθθ

Calcium Carbonate

Effect of continuous Stirring

In this experiment the overhead stirrer was used in such a way to only stir

the solution above the idol and not crush the idol with overhead stirrer and the

observations are given in table 10 below.

Table 10: Experimental condition

24

Weight of idols Water Weight of Na2CO3 Observations

8 kg 40 lit 8 kg 60 % disintegration in 6 hrs

During this experiment initial disintegration was faster with 40%

disintegration in 6 hrs however later it was very slow. Then fresh sodium

carbonate solution which was in the hollow part reacted with the idol from inside.

As there was no water circulation the reacted solution remained in the hollow part

and did not react further. Also the head part of the idol which was solid and dense

did not disintegrate even after 48 hrs. The small disintegrated portions were

embedded in the sludge and were not further disintegrated; hence the experiment

was not continued further.

Pros and Cons of the Na2CO3 method

1. Use of Na2CO3 forms a solid sludge of calcium carbonate.

2. Calcium carbonate can be used in different applications like cement

industries, cement bricks, and used in various medical applications.

3. Water soluble sulfate formed after the treatment is sodium sulphate

4. Sodium is very harmful for soil as well as for the plants and aquatic

life hence the solution cannot be discharged as such in agriculture land

or water without treatment

5. pH of the solution becomes highly alkaline (11-12) hence is not very

safe for handling

Due to all above mentioned drawbacks there is a need to use safer and

green carbonate salt for disintegration of POP hence ammonium

bicarbonate was used in all further experiments.

In order to overcome the problems faced before the design of the

experiment was changed and the idol was placed on mesh so that the formed

25

sludge settles down and the idol remains above the sludge. The water jet was

also used from the bottom of the idol using Tullu pump so that the disintegration

becomes faster from inside as well and there is better contact of fresh sodium

carbonate solution with unreacted POP. The pH of the final solution becomes

highly alkaline (pH 11-12) which is not safe to handle and needs special

precautions during handling. Hence use of sodium carbonate is not

recommended. Another disadvantage of using sodium carbonate used is

formation of soluble sodium sulphate. Sodium (Na) present in the solution is

harmful to agricultural land as well as aquatic life hence cannot be discharged in

the environment as such without any treatment. Hence the safer carbonate salt is

needed for disintegration of POP. Ammonium carbonate/bicarbonate is used for

making ammonium sulphate from calcium sulphate which is a well known

fertilizer (US2640757 A). Hence ammonium bicarbonate was used for

subsequent experiments as it would form soluble ammonium sulphate along with

calcium carbonate residue

CaSO4.1/2 H2O + (NH4) HCO3 (NH4)2SO4 + CaCO3 +

H2O

(POP) (Ammonium (Ammonium

(Calcium

Bicarbonate) sulphate)

carbonate)

Experiment with ammonium bicarbonate

As discussed above the experiment was carried out using

ammonium bicarbonate using modified experimental set up (as

shown in section 3.1).

Experimental set up = 200 lit drum with mesh fixed on a support for

keeping the idol + Overhead Stirrer + Tullu Pump (for water

circulation)


26

Weight of idol Water Weight of (NH4)HCO3 Observations

7.9 Kg 40 Lit 8 Kg 60 % disintegration in 9

hrs


Sr. No. Time (hr) Observation (% Disintegration)

1 0 Disintegration started

2 3 25

3 6 45

4 9 60

0 2 4 6 8 10

0

10

20

30

40

50

60

Dis

inte

gra

tion

(%)

Time(hr)

Effect of spraying from bottom

As the previous experiment showed promising results, to further improve

the rate of disintegration, idol was sprayed from bottom (instead of jet) using

ammonium bicarbonate solution so as to have better contact of ammonium

bicarbonate solution with POP. Also to study if rate of disintegration of dry idol

and wet idol are comparable, the idol was kept in plane water for 12 hrs before the

experiment was carried out and the observations are given below:


27

Weight of

dry idol

Wight of the wet

idol

Water Weight of

(NH4)HCO3

Observations

5 Kg 7 Kg 60 Lit 5 Kg 30% disintegration in 7

hrs, 65 % in 28 hrs,

94% in 86 hrs and 96 %

in 103 hrs


Sr .No Time (hr) Disintegration (%) Condition

1 0 Disintegration started With stirring

2 5 20 With stirring



5 23 63 Without stirring for 12 hrs


7 40 77 Without stirring for 12 hrs

8 43 77 Removed from solution &

kept in fresh solution without

stirring

9 45 78 Without stirring

10 86 94 Without stirring

28

0 20 40 60 80 100 120

0

20

40

60

80

100

Dis

inte

gra

tion

(%)

Time(hr)

The experiment showed almost

complete disintegration with only

part of head remaining at the end

of 103 hrs. Also when shower

was used from the bottom the

uneven disintegration was

observed. Hence in the next

experiments the spray was used

from the top. The above

experiments showed that rate of

disintegration are fast in the

beginning and slows down later

with time.

Effect of spraying from top

The experiment was performed as above except using spray from top instead of

bottom and the observation are given below:


Weight of dry

idol

Wight of wet idol Water Weight of

(NH4)HCO3

Observations

2.6 Kg 4.1 Kg 30 Lit 2.6 Kg 87 % disintegration in 44

hrs. The rate of

disintegration was almost

same throughout the

experiment.


29

Sr. No Time (hr) Disintegration (%) Remarks

1 0 Disintegration

started

2 4 25 With showering

3 6 45 With showering

4 14 64 With showering for 4 hrs






-5 0 5 10 15 20 25 30 35 40

0

20

40

60

80

100

Dis

inte

gra

tio

n(%

)

Time(hrs)

30

5. Pros and Cons of experiments:

1) The disintegration of POP using different carbonate salts generates

calcium carbonate as residue. Calcium carbonate finds applications in

mainly cement industry as well as additives in manufacturing cement

accessories like cement pipes, sheets, bricks, lids etc.

2) The soluble salts formed are sodium sulphate when sodium carbonate is

used which has many applications in chemical industries, however the

concentration of the final solution is ~ 20% and transportation of the

solution is not economical as well as concentration of 20% solution to get

solid sodium sulphate will be highly energy intensive and will not be

economical. The sodium in the solution is harmful to agriculture soil and

marine life as well as the pH of the final solution is highly alkaline (pH

11-12), hence it cannot be disposed in the environment without further

treatment.

3) In case of ammonium bicarbonate, soluble ammonium sulphate is formed

along with calcium carbonate residue. Ammonium sulphate is used as a

fertilizer for the plants as well as the pH of the final solution is almost

neutral (pH ~7) hence the aqueous solution of ammonium bicarbonate can

directly be used as fertilizer for plants.

4) Water circulation is important to keep the concentration of the ammonium

bicarbonate uniform throughout the experiment so as to have better

contact of ammonium bicarbonate with POP.

5) The rate of disintegration enhances at high temperature however heating

on large scale may not be economical if sodium carbonate is used. In case

of ammonium bicarbonate heating is not possible as ammonium

bicarbonate is not stable at high temperature and decomposes at 42ºC

releasing ammonia gas in the atmosphere.

6) Disintegration using spray has shown better results hence a better design

for uniform spraying ammonium bicarbonate solution from top as well as

bottom is needed.

31

6. Precautions

Following safety precautions needs to be taken for carrying out the experiment

using ammonium bicarbonate:

� Wearing safety goggles and mask is necessary during the

experiment, as some amount of ammonia is liberated during the

experiment and the vapors gives eye irritation as well as inhalation

for prolong period leads to health problems like bronchitis, asthma

and coughing.

� Experiment should be done in well ventilated open place, not near

residential area. The treatment should be done preferably in a

closed vessel.

� In case of direct contact of ammonia with skin, wash the infected

area with plenty of water.

� Direct inhalation of ammonia for prolonged period may create

problem in respiratory system.

7. Summary

� Expeiments carried out in lab using different carbonate salts (sodium

carbonate, sodium bicarbonate, ammonium bicarbonate) proved the

feasibility of the disintegration of POP idols using carbonate.

� Various parameters like amount of salt, concentration of salt,

temperature, stirring/circulation were optimized to minimize the time

for disintegration

32

� Ammonium bicarbonate was found to be best salt for POP

disintegration giving ammonium sulphate a well known fertilizer as

valuable byproduct.

8. Recommendation

� From all the experimental optimization the following conditions are

recommended for disintegration of POP idols: Preferable operating

conditions for the experiment are as follows:

20% solution (g/vol) of ammonium bicarbonate in water, POP to

ammonium bicarbonate ratio (wt/wt) 1:1

� Provision for keeping the idol on the mesh so that formed residue is

directly separated from idols during operation

� It was observed that using spray/jet from top as well as bottom

increases the rate of disintegrations hence the experimental set up

needs to be designed accordingly.

� Initial prototype setup can be designed for demonstrating the

feasibility of the operation on smaller scale (may be 4- 5 idols at a

time).

� The residue formed during the experiment can be used in cement

industry, as additive in the manufacturing of Cement accessories like

cement spun pipe, cement bricks, cement sheets of course it depends

on its purity & suitability for the product. Since it is good quality

calcium carbonate, it can be used as such for road making and

repairs.

� The ammonium sulphate formed is soluble in water and can be

directly used as fertilizer in agriculture land or gardens.

33

The drawing for the prototype of Ganesh idol visarjan (4-5 idols) as

designed by Mojj Engineering Systems Pvt Ltd is given below:

34

35

36

Annexure-1

Pilot run was designed and fabricated by Mojj Engineering System Ltd – Pune, in

consultation with NCL and Cummins for disintegration of Ganesh Idols.

The experiments were carried out on 4 numbers of household Ganesh Idol with

approximate 1foot height and 5 Kg weight.

The tank, fabricated as per sketch attached on previous page, has following features –

1. Material Mild Steel

2. Provision to contain 100lit of water and place 4 Ganesh Idols on Mesh size

of 1 square inch

3. Ammonium bicarbonate Re-Circulating system using electric pump

4. Nozzles for spraying solution from top and bottom of each idol.

5. Provision to accumulate sludge

The snaps for complete set up are shown below.

37

Trial conducted at Mojj Industry premises (Bhosari, Pune) with following procedure.

1. 25Kg of ammonium bicarbonate was added to 100Liters of water.

2. Water was recirculated using pump for initial few minutes to dissolve ammonium

bicarbonate to prepare solution.

38

3. Ganesh idols were placed on mesh; refer snap below

4. Experiment was started and ammonium bicarbonate solution was sprayed from

top and bottom of each idol using pump recirculating

5. The disintegration of idols was monitored each hour

Findings:

It was observed that; almost 90% disintegration of idols achieved in 5.5 hours after

starting the experiment.

Stepwise idol disintegration photographs are shown below.

39

40

41

42

Photograph 3, Photograph 4, 5, 6, etc………

These trials were conducted by by NCL,MOJJ and Cummins together and the further

optimisation would be done by NCL before the final handover to PMC.

It was also decided to conduct the experimentation in presence of NCL, PMC and

Cummins India Foundation.

The whole experimentation/trials including set up, chemicals is funded by Cummins

India Foundation

43

Annexure-II

After the pilot plant was designed and fabricated by Mr. Pol, Mojj

Engineering Systems Ltd, initial trials were conducted in their premises to check

the performance of the pilot plant. During the initial pilot plant trials in Mojj

premises pilot plant was modified many time by Mr. Pol for improvising the

performance. After the trials in Mojj factory, when the pilot plant design was

optimized for the performance, the set up was moved to NCL, Pune for further

experimentations for optimization of various parameters on pilot scale. Keeping

the water volume constant (250 lit) to the capacity of the tank of the pilot plant,

optimization studies were carried out on:

1. Ratio of ammonium bicarbonate to water

2. Maximum concentration of ammonium bicarbonate usable for experiment

3. Number of recycles of water

By considering these parameters experiments were carried out batch wise

(4 idols/batch).

4 Ganesh idols/ batch

Experiment 1

Initially in 250 lit water 25 kg ammonium bicarbonate was added to make 10%

concentration solution. The idols corresponding to 25 kg POP were disintegrated

in the batches of 4 idols at a time. The observations of the experiment are as

follows:

44

Water = 250 lit Ammonium bicarbonate = 25 kg Concentration of ammonium

bicarbonate = 10%

Batch 1 = Total wt of 4 idols 12 kg dry (17 kg wet wt)

Time for disintegration 3 h 30 min


Time for disintegration in 4 h


In this batch only partial (40%) disintegration was observed in 3 h.

(In 3rd batch only partial disintegration was observed. The weight of un-

disintegrated idols = 14 kg)

Observation for experiment 1

In 10% solution of ammonium bicarbonate for 25 kg ammonium bicarbonate, 41

kg dry (46 kg wet ) POP could be disintegrated. The average time for

disintegration was 3 h 30 min.

40% disintegration after 3 h in the last batch

In this experiment total 25 kg of ammonium bicarbonate disintegrated 41 kg dry (46 kg

wet) POP idols.

Experiment 2

45

In the next experiment one more batch of 25 kg ammonium bicarbonate was

added to the same solution of experiment 1 and further disintegration was carried

out as above. Batch 3 was continued for disintegration of remaining idols.

Batch 3 = Total wt of remaining idols 14 kg wet wt

Time for disintegration is 2 h


Time for disintegration is 4 h 30 min

Batch 5= Total wt of 4 idols 14 kg dry (18 kg wet wt)



In this batch no further disintegration was observed.


Addition of more 25 kg ammonium bicarbonate to previous solution resulted in

20% of total concentration of solution. And in this experiments total 45 kg dry (62

kg wet) pop idols could be disintegrated using 25 kg ammonium bicarbonate.

In this experiment total 45 kg dry (62 kg wet) POP could be disintegrated using

25 kg of ammonium bicarbonate

Experiment 3

46

In the same water from experiment 2 one more batch of 25 kg ammonium

bicarbonate was added to disintegrate the remaining idol in previous experiment.

Batch 6 was continued after addition of the fresh ammonium bicarbonate

however there was no further disintegration observed.


More addition of 25 kg to solution (making it total 30% concentration)

could not disintegrate the idols further. Therefore 20% ammonium bicarbonate

concentration is optimum for the experiment. As no disintegration could be

observed even after adding more ammonium bicarbonate due to saturation of salts

in the water and hence no further reaction of POP with ammonium bicarbonate

was possible.

Experiment 4

From the previous experiment 20% concentrating was found to be

optimum hence in this experiment directly 20% solution was used for the

disintegration of the idols. Hence the experiment was started with fresh batch of

250lit water.

Water = 250 lit, Ammonium bicarbonate = 50 kg, Concentration of ammonium

bicarbonate = 20%











47




It was observed that 80 kg dry (106 kg wet) POP was disintegrated using 50 kg

ammonium bicarbonate on an average time of 3 h 30 min

Complete disintegration of idols

One of the trials was demonstrated to PMC officials, Mr. Kunal Kumar (PMC

commissioner), Mr. Suresh Jagtap (Joint Municiple commissioner, Incharge

Department of solid waste management and vehicle depot, PMC) Mrs. Ketki

Ghatge(Medical officer,PMC)

48

Conclusion:

1) The optimum concentration of ammonium bicarbonate was found to

be 20%. If added in excess does not give any disintegration due to

saturation of the salt.

2) 20% concentration of ammonium bicarbonate resulted in optimum time

of disintegration (3-4 h).

3) The disintegration becomes visible within 30 mins from the start of the

pump. In the beginning the hollow portion of the idol, mainly the central

portion, which has a smaller wall thickness, starts dissolving. The other

parts with higher thickness, such as the base, the solid fingers, and the

crown are the last ones to disintegrate.

4) Batch wise addition of ammonium bicarbonate (10% per batch) or one

time addition of 20% ammonium bicarbonate has led to the almost

similar time for disintegration (3-4 h).

5) For 1 kg ammonium bicarbonate average 1.3 to 1.5 kg POP can be

disintegrated.

Observations and problems:

�� Decomposition of ammonium bicarbonate releasing ammonia gas

causes irritation of eyes and on inhaling causes discomfort.

�� Proper safety mask, goggles and gloves are essential for carrying out

the experiments

49

�� Due to the continuous run of the pilot plant increase in the temperature

of water was observed which led to decomposition of ammonium

bicarbonate thereby decrease in ammonium bicarbonate concentration in

solution.

�� As a result of rise in temperature coil of motor burns which leads to

leakage through piping joints.

�� Sometime the nozzles were choked due to the husk present in the POP

idols. The husk during circulation may get stuck in the nozzles leading to

choking of the nozzles. Due to such irregularities the time for

disintegration varied for some batches.

�� Due to the corrosive nature of the ammonium bicarbonate/ammonium

sulphate solution, rapid rusting of the plant was observed and over a

period led to leakages at few joints.

�� As it was also observed in subsequent batches calcium carbonate is

accumulated as sludge. During circulation of water along with sludge

there is difficulty for circulation due to formation of thick slurry which

leads to heating up of water and decomposition of ammonium bicarbonate.

It was also observed that corrosion & heating leads to leakages from the

pump gland and gaskets of the joints near the pump.

�� Safety gadgets used during the trials are shown below.

Masks Rubber Gloves

50

Safety Helmet

Documents

Report submitted on GANESH IDOL DISINTEGRATION Contributors