Sustainable Development in Natural Rubber

ACKNOWLEDGEMENT

It is with the utmost appreciation that we thank all those who

contributed time and thought to this project.

Also we would like to express sincere gratitude to our lecturer,

Dr. Shiromi Chandanika Karunaratne for her guidance.

We are deeply indebted to Mr. Nishantha Senevirathna, General

Manager of Sapumalkande Plantation of Lalan Agriculture Division.

We express our sincere appreciation to all the staff members and

the entire work force in Sapumalkande Plantation who offered their

time and knowledge of their experience.

CONTENT

LIST OF TABLES/FIGURES

ABSTRACT

The vision of Lalan Pvt. Ltd is to become a world class

natural rubber plantations management and processing company by

2014. The strategy implemented by them is to preserve, nurture &

protect the environment while growing, harvesting and manufacturing

natural rubber sheets.

This report was commissioned to examine the sustainable design

features and methods used in the factory and environmental impacts

caused by Lalan Pvt. Ltd. This companies main product is high

quality rubber sheets. The main aspects discussed are raw materials

and chemicals used, energy consumption, environmental and health

impacts. The impacts on the environment will be discussed regarding

each step of the process from extraction of rubber to the

production of natural rubber sheets. Various raw materials &

chemicals are used throughout the production process.

There are several steps when processing natural rubber latex

into rubber sheets. They are extraction of latex, coagulation,

milling & rolling, drying, dry rolling, folding and packing. The

energy consumption in each step will be discussed. The main focus

is to identify the ways of energy wastage and give recommendations

to conserve energy. Any factory does not waste energy willingly.

But unconsciously the energy is wasted. The ways which the energy

could be conserved will be discussed here. By optimizing energy use

the manufacturing cost could be decreased.

Various chemicals used in the production process are impacting

on workers’ health. The recommendations for safe use of those

chemicals and alternatives are discussed. The wastewater generated

during the manufacturing process is mixed with various chemicals.

How those chemical mixed wastewater is treated and proposals for

improvement in treating and reusing wastewater are discussed.

CHAPTER 1 – INTRODUCTION

1.1 INTRODUCTION TO THE COMPANY

Sri Lanka ranks as the eighth largest natural rubber producing

country in the world with a production of 129,243 MT in 2008, which

represents just a tiny share of around 1.3 per cent of the global

natural rubber production and 0.6 per cent of the global total

rubber production.

Natural rubber production in Sri Lanka declined significantly

and rapidly during the Asian financial crisis in 1997-1998 due to

low prices for natural rubber in the world market, but rebounded

strongly during the next decade.

Lalan Pvt. Ltd has been awarded a long term sub-lease of 42

years ending in 2045 from Bogawantalawa Plantations Ltd. to manage

plantation in 4 regions (Mahaoya, Pitiyakande, Sapumalkande and

Udabage) consisting of 13 estates.

The vision of Lalan Pvt. Ltd is to become a world class

natural rubber plantations management and processing company by

2014. The strategy implemented by them is to preserve, nurture &

protect the environment while growing, harvesting and manufacturing

natural rubber sheets. Lalan has been able to strive forward with

determination & focus to show the rest of their competitors that it

is entirely feasible to launch & manage a successful business

enterprise that benefits the community by providing jobs at the

same time preserving the nature for our future generation.

Lalan Rubbers (Pvt) Ltd was granted FSC(Forest Stewardship

Concil) status under the registration No SCS-FM/ COC-00127P valid

from 2nd September 2010 to 2nd September 2015. This certification is

subject to annual audits by FSC auditors. They now have the

facility to derive the benefits of trading locally and

internationally Estate produce, finished goods and Forestry

products with the FSC logo.

1.2 INTRODUCTION TO THE STUDY

Natural Rubber is processed after harvesting latex from the

most common rubber tree known as Hevea brasiliensis Rubber is an

important commodity for many countries. It is required in the

manufacture of numerous industrial equipments, household products,

Medical equipments, automobile and aircraft tires.

In this study, the mainly focused areas are raw materials and

chemicals used, the manufacturing process, the environmental and

health impacts. Identifying and quantifying the usage of raw

materials, chemicals and energy in manufacturing the final product

is a main objective of the study. The main aim of this study is to

find out ways and means of impacts on the environment and health

from the rubber industry and suggesting ways to minimize the

effects.

CHAPTER 2 – METHODOLOGY

2.1 INTRODUCTION

In this chapter the methodology used in the study is described. The

methods used to collect the data, and methods used to analyze data

and limitations when gathering information are discussed.

2.2 COLLECTION OF DATA

The following methods were adopted to derive the necessary

information for this study.

Visited the factoryOur group members visited the factory and gathered information

InterviewsInterviewed the General Manager of Sapumalkande Group and

the subordinates (field officer, factory officer and their assistants) working under him.

Analytical means

Data gathered from various reports from the factory

2.3 DATA ANALYSIS

After the data was collected it was organized and analyzed.

Assumptions were made when minimum amount of data were available.

The open-ended questions were analyzed and simplified relating to

the aims of the study.

2.4 LIMITATIONS

Seedling of rubber is planted and well nurtured by wateringWeeding, Digging holes, Draining, Panel marking, Fixing and removing rainguardsNatural rubber is tapped from rubber trees as latexLatex received will be processed to produce rubber sheets Not possible to get sensitive information from the top

management

Supply of false information

o Due to poor knowledge

Hiding information

o Due to revelation of organization’s weaknesses

CHAPTER 3 – FINDINGS/ PROPOSALS

3.1 MANUFACTURING PROCESSTAPPINGThe latex is tapped from rubber trees and transported to the factoryCOAGULATIONThe latex is collected in large tanks and formicacid is added DRY MILLING1/2 inch sheets are made / no water is used

3.1.1 HARVESTING LATEX

Latex is the sap of the commercially grown rubber tree Hevea

brasiliensis. Recently Hevea brasiliensis (Hevea) is the only

commercially grown natural rubber tree. Due to its limited

conditions when growing, more than 90% of the crop is cultivated in

South and Southeast Asia. It takes five to six years to grow to a

point where the tree is mature to harvest the latex.

The one who taps the rubber is called as the “ Tapper”. The

tapper must make a thin diagonal cut to remove bark. Then white

colored fluid latex flows out of the bark. The latex is collected

in buckets. After around 5 or 6 hours the fluid stops flowing. A

tapper collect a maximum of 40 liters of latex per day.

Then the harvested latex is transported to the factory.

3.1.2 PROCESSING AND COAGULATION

The rubber is put into a large storage tank (5500 litres

tank). Then Sodium Sulfite - Na2SO3 (0.05% - 0.15%) is added to

preserve latex from bacterial activity. Then the latex is put into

the bulking tank.

The latex is subjected to a DRC (Dry Rubber Content)

estimation. The amount of dry rubber present in 100mg of latex is

checked. Then a quality check is done to check whether there are

any pre coagulated latex is present. They are rejected from the

process. Next the non coagulated latex is strained using a 20 mesh

strainer. The larger barks shavings and leaves present in the latex

is removed. Then using a 50 mesh strainer dirt is removed.

TAPPINGThe latex is tapped from rubber trees and transported to the factoryCOAGULATIONThe latex is collected in large tanks and formicacid is added DRY MILLING1/2 inch sheets are made / no water is used

After that again to minimize the effect from bacteria sodium

bisulphate is added. 500g of Sodium Bisulphate for 100kg of DRC is

the ratio to get best performance of the chemical. Then

standardization of latex is done by diluting to 12.5% DRC with

filtered water. Yellow colour clots are formed after ealier step.

The fraction is removed by slowly stiring using a paddle. After the

1st fraction formation stops, the fractioned latex is passed to the

Settling tank through a 60 mesh sieve.

Again a DRC check is performed. Next two chemicals are added.

01. Oxalic acid – as a bleaching agent ( 125ml to

1000kg)

02. Formic acid – for coagulation (575ml – 675ml of 85%

formic acid used as 1% sol)

3.1.3 MILLING

The coagulated rubber is known as coagulum. The coagulum is

next passed to milling stage. These soft slabs of rubber is passed

through three machines with adequate water sprays.

01. Macerator – 05 passes

02. Diamond – 03 passes - 1/4” sheets

03. Smooth mill – 01 pass - 1/2” 5/16” 1/48”

inches sheets

The fresh water is used to wash away the chemicals which are

squeezed when coagulum is going through rollers. In each machine

cooling water is applied to rotors to reduce the heat generated.

3.1.4 DRYING

The thin laces are then draped over wooden frames and stored

inside the drying room. Radiators which circulate boiled water is

used to heat the room. The water is boiled using firewood. A

temperature of 35oC is maintained inside the drying room. The thin

rubber laces are left to dry around 3 days. 21 metres of dry rubber

and 500 liters of water is sufficient for 3 days.

3.1.5 FOLDING

A quality check is done after the drying process. Remove

insects, small dirt particles which are in rubber laces. Then the

laces are kept together and passed to the dry milling process.

3.1.6 DRY MILLING

The laces are passed through the dry mill. ½ inch rubber

sheets are made in this stage. No water is used during this

process. But cooling water is used to cool rotors.

3.1.7 PACKING

05 main things are done under this stage

01. Grading of rubber

02. Removal of dirt

03. Sizing to 17” x 23” slices

04. Bundling at 25kg packs

05. Bundles re-wrapped in DLPE film of gauge 300

3.2 RAW MATERIALS AND CHEMICALS

3.2.1 NATURAL RUBBER

The main raw material used in manufacturing rubber sheets is

latex of rubber tree Hevea brasiliensis. Latex is an emulsion of polymer

cis -1, 4- polyisoprene and water. The factory consumes about 5000

liters of latex per day.

Figure 1

Due to its molecular structure and high molecular weight

natural rubber has high performance properties that cannot be

achieved by artificially produced polymers. There is a tendency to

get allergic effects from synthetic rubber.

3.2.2 ALTERNATIVES FOR NATURAL RUBBER

Commercially grown Hevea brasiliensis tree cannot be grown in

varied conditions. These trees need a hot moist climate. They are

mainly grown in south and south east Asia. A tree takes around 6

years to become mature. This is relatively a longer period. Hevea

brasiliensis tree’s genetic base is yet not fully discovered. The

cloned plantations fail due to above mentioned reason.

Developed countries consumes 2.7 billion pounds of natural

rubber. The aircrafts need 100% natural rubber to meet heat

tolerance. Medical industry also mainly seek natural rubber which

has low allergic conditions than synthetic rubber. Rubber industry

has felt the shortage of natural raw materials and they are seeking

for alternatives for supply of natural rubber from Hevea

brasiliensis tree.

There are mainly 02 alternatives

01. Parthenium argentatum (Guayule)

02. Taraxacum kok-saghyz (Russian Dandelion)

Guayule is a shrub native to Mexico and southern USA which can

be cultivated in Mediterranean countries. It produces between 10

and 20% of its dry weight as rubber. This plant has been studied

for over 50 years as a domestic alternative rubber source to Hevea.

There are many advantages when using Guayule. 2/3 of the guayule’s

biomass has high energy value. Almost 85% -95% of the shrub has

commercial use after latex extraction. Now commercially grown

guayule plantations have been established to supply the medical

community. But it is not likely that guayule rubber will ever be

produced at sufficient quantities as a source of natural rubber to

compete with Hevea.

Taraxacum kok-saghyz (Russian Dandelion) or TKS. TKS is a

plant which produces high quality natural rubber in its tap roots.

This crop is suitable for temperate climate zones in Europe ranging

from North Spain to Scandinavia. The rubber produced by TKS has a

comparable molecular weight to Hevea rubber. It is a great

advantage in manufacturing high quality rubber.

These two alternatives offer crops that can be grown in

different conditions. Guayule can be grown in Mediterranean

climates and TKS can be grown in temperate climate zones.

3.2.3 CHEMICALS AND ALTERNATIVES

There are several chemicals used in the process.

01. Sodium Sulfite - to stop coagulation of latex

02. Sodium bisulphate – as an antibacterial

03. Formic acid – to coagulation

04. Oxalic acid – bleaching and coagulation

05. Sodium hydroxide – to treat wastewater

Formic acid make high quality rubber with good color. Formic

acid is ideal for transforming latex into homogenous coagulum.

Formic acid is a environmental compatible chemical which is

biodegradable and does not result in phosphate or nitrate loading

of wastewater. It also has a low chemical oxygen demand(COD).

The alternatives used for formic acid are acetic acid and

butter milk. The rubber made from butter milk can be categorized

into RSS-4 grade. Superior quality rubber can be made by

coagulation using butter milk. As it being totally a organic

product no side effects or allergies are caused. The processing

cost can be reduced by 80%.

Sodium Bisulphate works by releasing sulfur dioxide gas which

hold back bacterial and fungal growth and prevent the

discoloration.

Oxalic acid is the main bleaching agent added. It is a toxic

chemical. Oxalic acid is inexpensive, quick and easy to use.

Sodium Hydroxide is also known as caustic soda, Caustic soda

is commonly used in the neutralization of acid industrial waste.

The pH value of treated water is between 6-7. An alternative for

sodium hydroxide is Magnesium hydroxide. There are many advantages

in magnesium hydroxide when compared with caustic soda. A fewer

amount of magnesium hydroxide are required to neutralize the same

amount of acid. Replacing Sodium Hydroxide with magnesium hydroxide

may significantly increase the treated water quality.

3.3 ENERGY CONSUMPTION

Raw Materials

Transport

Manufacturing

Packing and

Energy

Energy

Energy

The main source of energy used in the factory is electricity.

The 80% of energy need is fulfilled by electricity. There are 04

machines that are electrically operated.

01. Macerator

02. Diamond

03. Smooth roller

04. Dry mill

Each machine consumes equal amount of electricity if operated

for equal time. Because same type of motor is used for each

machine. The efficiency of machines play a main role in energy

consumption. The efficiency of machines after a certain repair is

above 85%. But with time it decreases to 60-65%.

The energy consumption of the factory is averagely 20 000 – 25

000 KWh per month. The monthly current bill is approximately around

Rs.4 50 000.

The other types of energy used in the process are,

01. Petroleum fuel – for transportation and for

generators.

02. Firewood – for drying rubber laces

Around 21m of dry wood is used for 3 days in the drying process of

rubber laces.

When considering about the transportation, there are less data

available for the amount of fuel consumption for a period of time.

So the data was collected about the distance the latex transporting

vehicle is travelled and came up with a assumption of fuel usage

per month.

Average Kilometers travelled per day –

16 Km

Average Kilometers per liter of fuel – 6.5 Km/Liter

Fuel Consumption per month – 73.84 Liters/

Month

If there is a power failure a generator is used to generate

electricity in the power plant. But according to the site manager

the amount of power cuts are less so the amount of fuel usage is

not much.

3.3.1 ENERGY CONSERVATION

The methods used by the factory to conserve energy can be listed as

follows.

01. Use daylight to do the factory work

02. Turning Off Idle running machines

03. Proper maintenance of the machines

Occurrence of defective items can lead to more energy wastage,

raw material wastage and increase of cost. To make sure that the

good quality rubber are manufactured following measures should be

taken.

01. Check for good quality raw materials

02. Check the condition of the equipments in each

process

3.3.2 RECOMMENDATIONS

A factory should be responsible for the consumption of energy

and taking countermeasures to reduce the energy wastage. The

following values should be taken into consideration first to get a

knowledge about the current situation of the factory.

Amount of fuel consumption

Volume of rubber transported

Amount of electrical power consumption

Weight of rubber produced

The numerical value of the unit consumption should be checked

at least once in a month. So that the management can compare with

the previous values and take steps to reduce energy consumption.

The reduce in the unit consumption means there should be a

improvement after taking countermeasures.

These are some recommendations to reduce energy consumptions in a

the factory.

01. Optimization of manufacturing capacity of machines

02. Prevention of idle running machines and leaks

03. Reduction of defective items

04. Establishment of advanced technologies

05. Utilizing electric power wisely can reduce cost / working

in off peak hours

06. Making workers conscious on conserving energy / energy

conservation sessions

3.4 WATER CONSUMPTION

The factory consumes approximately 75000 Liters of water per

month. It takes 1 Liter of water to produce 1Kg of dry rubber. The

factory uses water for cooling and washing away chemicals. Even

though the water which are used for washing away purposes are

treated, the water used for cooling purposes are not reused. Mainly

they use water to cool the heat generated in rotors of the

machines.

Figure 01 – Cooling water is not reused

3.4.1 WATER CONSERVATION

The only activity the factory does for water conservation is

treating chemical mixed water and reusing them for watering

plantations.

Saving water is as important as saving energy. So the cooling

water which is not reused should be reused by the factory by

implementing a system. One of the following designs can be used to

establish a water circulating system for process.

The used water for cooling ( warm water ) process is sent to a

overhead tank consisting of a cooling fan. The warm water is cooled

and return to the process. This recirculation water system can be

used to reuse the cooling water

This is known as the wet cooling tower system. This is a

famous method used in most countries . There can be some waste of

water through evaporation. But it is relatively a small amount.

3.5 HEALTH IMPACTSThe health impacts are mainly occurred due to use of chemicals when

processing rubber latex. There are several chemicals used in the

manufacturing process. They were mentioned earlier in a previous

sub chapter. The health impacts are discussed separately for each

chemical group. These health effects also include lung conditions

caused by dust and fumes inside the factory ,injuries caused by

machinery.

The factory does not have any cases reported about serious health

effects like cancers and lung diseases. But there have been cases

reported about minor injuries by machinery and burns due to

chemicals.

3.5.1 FORMIC ACID

The hazards of the solutions of formic acid depends on the

concentration. The concentration above 10% is considered as

corrosive and above 90% are considered as highly corrosive. The

skin or eye contact with concentrated liquid or vapors of formic

acid can be dangerous. The chronic exposure to formic acid can

cause kidney damages. Inhalation of formic acid fumes can cause

severe lung injury. Research conducted on exposure to

microorganisms have demonstrated this chemical can change the

genetic material usually DNA. So the workers should be cautious

when handling concentrated solutions.

3.5.2 SODIUM SULFITE

Sodium sulfite is irritating to the eyes. Symptoms of

irritation may be itching, redness or tearing. This chemical can

affect the respiratory system also. It may cause wheezing,

shortness of breath.

3.5.3 SODIUM BISULPHATE

Sodium bisulphate causes irritations of the nose and throat.

Swallowing can cause burns of the mouth, throat, stomach, leading

to death.

3.5.4 OXALIC ACID

Oxalic acid cause burns if absorbed through the skin or in

contact with the eyes. If inhaled, it can cause cough, wheezing and

inflammation of lungs.

3.5.5 SODIUM HYDROXIDE

Inhalation can cause severe irritation to nose and throat.

Contact with eye causes burns.

3.5.7 HEALTH & SAFETY POLICY OF THE EMPLOYEES

The Lalan Pvt. Ltd itself have set policies for all the

employees to maintain a good standard and for the wellness of the

workers.

All workers should wear and have:

• Helmet with ear and eye protection –when engaged in

hazardous work

• Wear raincoats when working in the rain

• First aid kit (must be attached to the supervisors belt at

all times)

• Mobile phone or equivalent device for emergencies

• Training on safety and health procedure ( each training is

valid only for 06 months)

General knowledge on safety :

• Proper instructions for emergency situations

• Been informed about the location of nearest hospital

• Mobility to enter hospital

All Contractors should adhere to their contract agreements and

will be terminated if the terms & conditions are violated

Health and safety training courses are given twice a year by

suitably qualified persons.

3.6 ENVIRONMENTAL IMPACTS

The main pollutant released in manufacturing process is chemical

mixed wastewater. The rejected rubber due to bacterial effect are

burnt. This can cause air pollution. The chemical mixed rubber

smoke is toxic. When burning firewood there can be several by

products such as ash, smoke containing CO2 and water vapor.

Figure – ash collected

Figure – chimneys

The chemical water discharged in the milling processes are acidic

due to use of acids in previous stages. The odor causing substances

can be present in the wastewater.

3.6.1 MINIMIZING ENVIRONMENTAL IMPACTS

The factory has taken steps to treat the chemical wastewater

generated during the process.

Figure – chemical water collected Figure – Treating chemical water with NaOH

The Chemical wastewater is first collected in large cement

tanks. Then it is sent to other tank for mixing with NaOH. 5Kg of

NaOH is first diluted with water and a solution is made. After the

solid NaOH is totally dissolved in water, small amounts of the

solution are added and checked for the pH value. The pH value

should be maintained between 6.8 – 8.0.

The treated wastewater is used for watering the plantations.

The pH value of treated wastewater is between 6 -7 pH. So there is

no harm in watering the plants.

Figure – checking the pH Figure – off qualityrubber

value of treated water

The off quality rubber are sold to small factories. The remainingis sent to India for recycling.

3.6.2 RECOMMENDATIONS

The wood burnt ash can be used as a fertilizer and it can be

sold to soap making companies as ash is used to make soap

products

Implementing the drying towers with new technologies in order to

get rid of smoke and ash

Proper maintenance of the equipments to avoid unnecessary sound

pollution

Burn only clean, dry wood that has been dried for at least 6 months.

3.7 LIFE CYCLE OF THE RUBBER PRODUCTSThe following figure shows the life cycle of rubber products.

Figure – Life cycle of Rubber products

A simplified process tree for processing of rubber sheets can be

shown as follows. For processing 3 Liters of Latex into rubber

sheets the following amounts of chemicals, water and energy are

consumed

Figure – Simplified process tree for A rubbersheet

3.7.1 GLOBAL AND REGIONAL IMPACTS

Global impact categories :

Source: Burns waste rubber & firewood Effect: Increase in temperature, VOC, hydrocarbon

Source: Chemicals (Nexobleach. Sodium Sulfite, Sodium hydroxyde etc.)

Effect: Reduction of possibilities for future generations

Regional impact categories :

Source: Transport, energy, agriculture Effect: Damage to woodlands, lakes and buildings (SOx, NOx,

NH3 )

Source: Transport, energy, industry (Hydrocarbons etc.) Effect: Ozone formation (Damage of lung tissue etc. )

Source: Transport, energy, agriculture Effect: Damage to woodlands, lakes and buildings (SOx, NOx,

NH3 )

3.7.2 SUSTAINABLE KEY FEATURES OF THE FACTORY

• Rubber plantation system

• Use day light to work in factory

• Use treated waste water to cultivate Lalan tea estate.

• Send rejected rubber to recycle

White boxes are not included in the inventory

• Use dry rubber trees as firewood

CHAPTER 4 - DISCUSSION

The purpose of this study is to identify the sustainable

design features, methods, how the application of those techniques

help to protect the environment and the society, the waste

generation, actions already taken for them, areas that could be

improved.

This study found that there are several environmental impacts

caused during processing of raw rubber into rubber sheets. The

Lalan Pvt. Ltd has already taken steps to minimize the effects. But

there are several sections that could be improved to minimize

environmental impacts.

There are ways in which the energy is wasted inside the

factory. There are less records about the energy related data

inside the factory such as detailed descriptions of the motors

used, the fuel consumption for transporting latex. The wastage of

water during the cooling process was identified. This water is not

reused. So that in a earlier chapter a very famous method called

“wet cooling tower system” was discussed as a recommendation for

reusing cooling water.

There were some limitations when conducting the study. The

factory did not have any records related to health effects such as

serious diseases like cancers etc. The field officers might be

hiding them or actually there are no cases reported. There are

limited data available for details about energy equipments much.

Some of the equipment labels have been faded away. These details

are direct details from staff and the data like monthly electricity

bill and water bill were taken by records.

CHAPTER 5 – CONCLUSIONThe main emission in the factory that causes much damage to

the environment is wastewater mixed with chemicals. But in this

factory the wastewater also treated using a purification system.

The other problem is not reusing cooling water used by the

machines. Using a proper water circulating system could avoid the

wastage of water. The rejected rubber due to bacterial infections

are burnt outside the factory. These may contain chemicals. By

using proper disposal methods the damage to the environment can be

minimized. The smoke and ash is released because of using dry

firewood used in the drying towers. By using recommended

alternative methods can reduce these emissions.

Mostly the health effects are caused by chemicals used in the

process. The chemicals should be handled safely. The proper

training should be given to employees in order to minimize the

health effects. There are several minor health impacts like heavy

noise and minor injuries due to equipments.

Several sustainable design features of the process were

identified during the study such as using daylight to do

activities, watering tea plantations using treated water etc.

As the demand for the natural rubber goes high, the world is

looking for alternatives. The Guayule, Russian Dandelion are

alternatives for natural rubber that has been found yet. But these

alternatives are still not superior to Hevea brasiliensis.