MICRO DUST in COTTON
Textile
industry is the second largest industry in the world next to agriculture. In
India, the textile industry contributes substantially to the foreign exchange
earned by the country. The textile industry is providing employment to numerous
people in the country. The emphasis on awareness about the environmental
concern such as air, water and noise pollution during the processing from fibre
to fabric is essential in the present circumstances. There were 1818 mills
(non-SSI) in the country as on January 31, 2007 with a capacity of 35.37
million spindles, 4, 48,000 rotors and 69,000 looms. Information regarding
cotton dust exposure impacts on workers and its control strategies is missing
among textile employers, management and employees. The main aim of this paper
is to provide an overview of this issue such as causes, consequences, health
hazards arising due to cotton dust and air quality standards available are
discussed to facilitate textile mill employers and management to establish
cotton dust control strategies to save their workers from its harmful health
impacts.
Cotton
dust:
Cotton
dust is defined as dust present in the air during the handling or processing of
cotton, which may contain a mixture of many substances including ground up
plant matter, fiber, bacteria, fungi, soil, pesticides, non cotton plant matter
and other contaminants which may have accumulated with the cotton during the
growing, harvesting and subsequent processing or storage periods.
Any dust present during the handling and processing of cotton through the weaving or knitting of fabrics, and dust present in other operations or manufacturing processes using raw or waste cotton fibers and cotton fiber byproducts from textile mills are considered cotton dust within this definition.
The cotton microdust is less to ignite and causes serious environmental problems and health hazards. This paper presents an experimental study, which investigates the potential use of cotton microdust to produce new and lightweight brick for construction industries. The physical and mechanical properties of brick mixes having different levels of cotton microdust ratio were investigated. The test results recorded for compressive strength, unit weight, and water absorption values satisfy the relevant required standards for normal construction bricks. The results show that the replacement of clay soil and cement by cotton microdust does not exhibit a sudden brittle fracture even beyond the failure loads, indicates high energy absorption capacity, reduces the unit weight dramatically, and introduces smother surface compared to the current concrete bricks in the market. The results also show that usage of cotton microdust with different mixing ratios for bricks will give light-weight composite, and brick could be an economical alternative to be used for partition of board concrete blocks and sound barrier panels.
Classification of Cotton Dust:
Table: 1
Type |
Size of
the particle (μm) |
Trash |
Above 500 |
Dust |
50-500 |
Micro
dust |
15-50 |
Breathable
dust |
Below 15 |
The
Micro-dust comprises 50-80% fibre fragments, leaf and husk fragments, 10-25 %
sand and earth and 10-25 % water-soluble materials. The high proportion of
fibre fragments indicates that a large part of the micro-dust arises in the
course of processing. Nearly about 40 % of the micro dust is free between the
fibres and flocks, 20-30 % is loosely bound, and the remaining 20-30 % bound to
the fibres.
Types
of Dust:
1. Inhalable
Dust: It
is a term used to describe dust that is hazardous when deposited anywhere in
the respiratory tree including the mouth and nose.
Fig.1 Human Respiratory system
2. Thoracic
Dust: It
is defined as those materials that are hazardous when deposited anywhere within
the lung airways and the gas exchange region.
3. Respirable
Dust: Respirable
dust is defined as that fraction of the dust reaching alveolar region of the
lungs.
Generation
of the Cotton Dust during Manufacturing:
- Ginning factories
discharge large amounts of cotton dusts. Cotton ginning and pressing have
been identified as traditional industries under the unorganized sector which
functions on a seasonal basis.
- Major problem of cotton
dust exists in the blow room and carding section of spinning mill whereas
exposure level in other areas is comparatively not much.
- Poor Relative Humidity
follow-up in the department.
- Blow-down, or blow-off,
is the cleaning of equipment and surfaces with compressed air.
- Cleaning of clothing or
floors with compressed air.
- Improper handling of
waste during transportation.
- Insufficient
ventilation system.
- Improper suction system
in the key areas such as blow room and carding and wherever there is a
chance of dust generation.
- When materials such as
laps, sliver cans and roving bobbins are delayed in process or stored for
an extended period in an area where there is a likelihood of significant
dust or lint accumulation. Poor follow-up in covering the material leads
to dust formation.
- Usage of spring loaded
cans and carts as waste receptacles creating dust dispersion during
compression of the spring loaded bottoms.
- Poor working procedures
and cleaning methods.
Health
Hazards Associated with Cotton Dust Exposure:
Workers
exposed to cotton dust laden environment generally become patients of
byssinosis.
Byssinosis:
It
is a breathing disorder that occurs in some individuals with exposure to raw
cotton dust. Characteristically, workers exhibit shortness of breath and/or the
feeling of chest tightness when returning to work after being in the mill for a
day or more. There may be increased cough and phlegm production.
Change
in the levels of ESR, LDH3 and Histamine may be used as indicators to assess
pulmonary dysfunction in the workers those are exposed to cotton dust. It was
suggested that the low hemoglobin and poor immunity against diseases may also
predispose the out come pulmonary dysfunction at an earlier stage. Cotton dust
extract induces the release of histamine from samples of human lung tissue in
vitro. Therefore it is believed that histamine release is responsible for the
major symptoms of byssinosis, viz, "chest tightness".
Dr.
Richard Schilling, a British physician developed a system of grading workers
based on their breathing complaints on the first workday of the week.
Schillings classification grades byssinosis according to how far it has
progressed. Schillings classifications are as follows.
- Grade 0 = No complaints
of breathing problems.
- Grade 1/2 = Chest
tightness and/or shortness of breath sometimes on the first day of the
workweek.
- Grade 1 = Chest
tightness and/or shortness of breath always on the first day of the
workweek.
- Grade 2 = Chest
tightness and/or shortness of breath on the first workday and on other
days of the workweek.
- Grade 3 = Chest
tightness and/or shortness of breath on the first workday and other days
as well as impairment of lung function.
It
is believed that the degree or severity of response for individuals with
symptoms of byssinosis is related to the dust level in the workplace. The
beginning steps in yarn preparation generally produce more dust. Therefore, the
closer to the beginning of the process, the higher will be the dust level and
the more likely the pulmonary reaction or response for some workers.
Permissible
Exposure Limits for Cotton Dust for Different Work Areas:
Table: 2
Department |
PEL
(Micrograms per cubic meter) |
Opening |
200 |
Picking |
200 |
Carding |
200 |
Combing |
200 |
Roving |
200 |
Spinning |
200 |
Winding |
200 |
Warping |
200 |
Slashing |
750 |
Weaving
and Knitting |
750 |
Waste
house |
750 |
Medical
Monitoring:
Medical
examinations are to be provided to prospective employees prior to their initial
assignment. As a minimum, the examinations should include:
- A medical history to
identify any existing health problems or diseases that may affect
breathing.
- A standardized
respiratory questionnaire inquiring about such concerns as cough, chest
tightness and smoking history.
- A pulmonary function
(breathing) test including the forced vital capacity (FVC), the amount of
air one can force out after taking a deep breath and forced expiratory
volume in 1 second (FEV1), the amount of air forced out during the first
second of expiration.
Environmental
Exposure monitoring:
- Sampling of the
workplace must be done at least every six months to determine the amount
of cotton dust in the environment.
- Measurements must be
representative of all employees in the workplace.
- Sampling will be done
in all work areas and on each shift.
- Sampling is done for a
period equal to at least three-quarters of the shift.
- While sampling is being
done, other information is collected that may pertain to the generation of
cotton dust. The percent of cotton fiber in the mix; the grade of the
cotton and where it was grown; types of yarn being run; and the number and
types of machines operating in each area may all affect the amount of
cotton dust in the workplace.
Vertical
Elutriator:
It
is used to monitor employee exposure to cotton dust in the workplace. Airs is
drawn into the vertical elutriator at a specified speed, and particles of 15
microns or smaller are collected on a filter. The particles collected are
measured to determine the amount of respirable dust (dust that can get into 4
the lungs) there is in the work area. It is important to realize that other
dusts, such as starch or oil mist are also collected
on
the filter and may contribute to the cotton dust levels.
Fig 2 Vertical Elutriator
Dust
Control Measures:
Monitoring
of cotton dust concentration in the occupational environment
Provide
medical surveillance to the cotton dust exposed workers
Establishing
safe working practices to reduce the exposure level
Training
and education of workers
Engineering
controls to reduce the emission
Use
of dust masks
Preventive
measures to be followed during manufacturing process:
Sustainable conversion of cotton dust
There are a number of ways in which cotton
dust can be disposed of sustainably.
- Biogas production: In his research titled
'Production of Biogas from Willow Dust', RH Balasubramanya states that
willow dust contains traces of wax, cellulose, hemicelluloses and lignin.
It is found that the substances which have C: N ratios of 25:1 are found
to be optimum for biogas production. In willow dust, this ratio is of 30:1
(C: 1 (C: N) and hence is suitable for biogas production.
- Vermicomposting: Considering the organic
nature of cotton dust, with the use of vermicomposting technology and
enzyme technology the cotton dust may be converted into bio-compost.
Vermicomposting is a technology for converting solid organic waste into
highly beneficial and rich compost which can be used as fertiliser to
enhance soil fertility. The worms create a home for millions of
microorganism that help in reducing the toxicity of waste. This is viewed
as the organic, sustainable, and eco-friendly alternative to chemical
insecticides and pesticides which cause harmful effect on the health of farmers.
Cotton uses approximately 25 per cent of the world's insecticides, due to
which large number of farmers die. Therefore, this could be used for
organic farming which would also help in reducing dependence on the costly
and hazardous chemicals and pesticides.
- Fuel for boiler: The dust contains traces
of wax which when burnt releases energy which can be utilised as fuel for
boilers. This would help the industry to save on fuel costs, and also it
is the sustainable reuse of the waste which would otherwise release
obnoxious smell into the environment and if burnt in air, then increases
the carbon dioxide levels of the atmosphere.
General
practices:
- Usage of compressed air
for cleaning purposes should be prohibited when other means of cleaning
are possible. Where blow-down cleaning is done (meaning general cleaning
of the entire room, including the walls and ceilings ventilation ducts),
employees performing the cleaning must wear respirators.
- All other employees not
involved with the blow-down cleaning must leave the area.
- Cleaning of clothing or
floors with compressed air is prohibited.
- Floor sweeping will be
done by vacuum or other methods designed to minimize the breathing of
dust.
- Waste will be handled
by mechanical means. Manual handling should be limited as much as
possible.
- Ventilation systems
should be inspected regularly.
Work
practices during Material handling and cleaning:
- Cotton, Cotton waste
and materials containing cotton dust should be stacked or handled properly
in such a way that will reduce dust level.
- Brooms should be used
properly so that dust will be controlled and vacuum cleaners should be
used wherever dust control is difficult.
- When cleaning machines
with brushes or cloths, the individual doing the cleaning should stroke
the waste from top to bottom as far from the face as possible. Surfaces
should not be beaten or fanned during cleaning.
- Waste should be placed
in the corresponding waste storage container immediately before
accumulating in the floor.
- Waste receptacles or
waste transport containers should be placed in the respective places such
that disturbance creating by any means would be avoided.
- Waste receptacles
should not be overfilled such that material spills to the floor during
storage or transport to the waste godown.
- Spring-loaded cans and
carts should not be used as waste receptacles in order to avoid dust
dispersion during compression of the spring-loaded bottoms.
- When materials such as
laps, sliver cans and roving bobbins are delayed in process or stored for
an extended period in an area where there is a likelihood of significant
dust or lint accumulation, the materials should be covered. The storage
area and the covers should be periodically cleaned to prevent lint and
dust accumulation.
Conclusion:
As
being the largest contributor to the national economical growth, we are giving
atmost emphasis to the textile industry especially in terms of developing high
speed machineries, versatile machines and high quality products. At the same
time we must focus on health conditions of the human involving in the
manufacturing process and environmental conditions. Textile management and
employer should follow the work procedures to control the cotton dust exposure
to workers. The cotton dust which is creating health hazards to the lakhs of
labours involving in the textile manufacturing process should be controlled by
creating awareness among the workers and by the effective management.
Textile
industry is the second largest industry in the world next to agriculture. In
India, the textile industry contributes substantially to the foreign exchange
earned by the country. The textile industry is providing employment to numerous
people in the country. The emphasis on awareness about the environmental
concern such as air, water and noise pollution during the processing from fibre
to fabric is essential in the present circumstances. There were 1818 mills
(non-SSI) in the country as on January 31, 2007 with a capacity of 35.37
million spindles, 4, 48,000 rotors and 69,000 looms. Information regarding
cotton dust exposure impacts on workers and its control strategies is missing
among textile employers, management and employees. The main aim of this paper
is to provide an overview of this issue such as causes, consequences, health
hazards arising due to cotton dust and air quality standards available are
discussed to facilitate textile mill employers and management to establish
cotton dust control strategies to save their workers from its harmful health
impacts.
Cotton
dust:
Cotton
dust is defined as dust present in the air during the handling or processing of
cotton, which may contain a mixture of many substances including ground up
plant matter, fiber, bacteria, fungi, soil, pesticides, non cotton plant matter
and other contaminants which may have accumulated with the cotton during the
growing, harvesting and subsequent processing or storage periods.
Any
dust present during the handling and processing of cotton through the weaving
or knitting of fabrics, and dust present in other operations or manufacturing
processes using raw or waste cotton fibers and cotton fiber byproducts from
textile mills are considered cotton dust within this definition.
The cotton microdust is less to ignite and causes
serious environmental problems and health hazards. This paper presents an
experimental study, which investigates the potential use of cotton microdust to
produce new and lightweight brick for construction industries. The physical and
mechanical properties of brick mixes having different levels of cotton
microdust ratio were investigated. The test results recorded for compressive
strength, unit weight, and water absorption values satisfy the relevant required
standards for normal construction bricks. The results show that the replacement
of clay soil and cement by cotton microdust does not exhibit a sudden brittle
fracture even beyond the failure loads, indicates high energy absorption
capacity, reduces the unit weight dramatically, and introduces smother surface
compared to the current concrete bricks in the market. The results also show
that usage of cotton microdust with different mixing ratios for bricks will
give light-weight composite, and brick could be an economical alternative to be
used for partition of board concrete blocks and sound barrier panels.
Classification
of Cotton Dust:
Table: 1
Type |
Size of
the particle (μm) |
Trash |
Above 500 |
Dust |
50-500 |
Micro
dust |
15-50 |
Breathable
dust |
Below 15 |
The
Micro-dust comprises 50-80% fibre fragments, leaf and husk fragments, 10-25 %
sand and earth and 10-25 % water-soluble materials. The high proportion of
fibre fragments indicates that a large part of the micro-dust arises in the
course of processing. Nearly about 40 % of the micro dust is free between the
fibres and flocks, 20-30 % is loosely bound, and the remaining 20-30 % bound to
the fibres.
Types
of Dust:
1. Inhalable
Dust: It
is a term used to describe dust that is hazardous when deposited anywhere in
the respiratory tree including the mouth and nose.
Fig.1 Human Respiratory system
2. Thoracic
Dust: It
is defined as those materials that are hazardous when deposited anywhere within
the lung airways and the gas exchange region.
3. Respirable
Dust: Respirable
dust is defined as that fraction of the dust reaching alveolar region of the
lungs.
Generation
of the Cotton Dust during Manufacturing:
- Ginning factories
discharge large amounts of cotton dusts. Cotton ginning and pressing have
been identified as traditional industries under the unorganized sector which
functions on a seasonal basis.
- Major problem of cotton
dust exists in the blow room and carding section of spinning mill whereas
exposure level in other areas is comparatively not much.
- Poor Relative Humidity
follow-up in the department.
- Blow-down, or blow-off,
is the cleaning of equipment and surfaces with compressed air.
- Cleaning of clothing or
floors with compressed air.
- Improper handling of
waste during transportation.
- Insufficient
ventilation system.
- Improper suction system
in the key areas such as blow room and carding and wherever there is a
chance of dust generation.
- When materials such as
laps, sliver cans and roving bobbins are delayed in process or stored for
an extended period in an area where there is a likelihood of significant
dust or lint accumulation. Poor follow-up in covering the material leads
to dust formation.
- Usage of spring loaded
cans and carts as waste receptacles creating dust dispersion during
compression of the spring loaded bottoms.
- Poor working procedures
and cleaning methods.
Health
Hazards Associated with Cotton Dust Exposure:
Workers
exposed to cotton dust laden environment generally become patients of
byssinosis.
Byssinosis:
It
is a breathing disorder that occurs in some individuals with exposure to raw
cotton dust. Characteristically, workers exhibit shortness of breath and/or the
feeling of chest tightness when returning to work after being in the mill for a
day or more. There may be increased cough and phlegm production.
Change
in the levels of ESR, LDH3 and Histamine may be used as indicators to assess
pulmonary dysfunction in the workers those are exposed to cotton dust. It was
suggested that the low hemoglobin and poor immunity against diseases may also
predispose the out come pulmonary dysfunction at an earlier stage. Cotton dust
extract induces the release of histamine from samples of human lung tissue in
vitro. Therefore it is believed that histamine release is responsible for the
major symptoms of byssinosis, viz, "chest tightness".
Dr.
Richard Schilling, a British physician developed a system of grading workers
based on their breathing complaints on the first workday of the week.
Schillings classification grades byssinosis according to how far it has
progressed. Schillings classifications are as follows.
- Grade 0 = No complaints
of breathing problems.
- Grade 1/2 = Chest
tightness and/or shortness of breath sometimes on the first day of the
workweek.
- Grade 1 = Chest
tightness and/or shortness of breath always on the first day of the
workweek.
- Grade 2 = Chest
tightness and/or shortness of breath on the first workday and on other
days of the workweek.
- Grade 3 = Chest
tightness and/or shortness of breath on the first workday and other days
as well as impairment of lung function.
It
is believed that the degree or severity of response for individuals with
symptoms of byssinosis is related to the dust level in the workplace. The
beginning steps in yarn preparation generally produce more dust. Therefore, the
closer to the beginning of the process, the higher will be the dust level and
the more likely the pulmonary reaction or response for some workers.
Permissible
Exposure Limits for Cotton Dust for Different Work Areas:
Table: 2
Department |
PEL
(Micrograms per cubic meter) |
Opening |
200 |
Picking |
200 |
Carding |
200 |
Combing |
200 |
Roving |
200 |
Spinning |
200 |
Winding |
200 |
Warping |
200 |
Slashing |
750 |
Weaving
and Knitting |
750 |
Waste
house |
750 |
Medical
Monitoring:
Medical
examinations are to be provided to prospective employees prior to their initial
assignment. As a minimum, the examinations should include:
- A medical history to
identify any existing health problems or diseases that may affect
breathing.
- A standardized
respiratory questionnaire inquiring about such concerns as cough, chest
tightness and smoking history.
- A pulmonary function
(breathing) test including the forced vital capacity (FVC), the amount of
air one can force out after taking a deep breath and forced expiratory
volume in 1 second (FEV1), the amount of air forced out during the first
second of expiration.
Environmental
Exposure monitoring:
- Sampling of the
workplace must be done at least every six months to determine the amount
of cotton dust in the environment.
- Measurements must be
representative of all employees in the workplace.
- Sampling will be done
in all work areas and on each shift.
- Sampling is done for a
period equal to at least three-quarters of the shift.
- While sampling is being
done, other information is collected that may pertain to the generation of
cotton dust. The percent of cotton fiber in the mix; the grade of the
cotton and where it was grown; types of yarn being run; and the number and
types of machines operating in each area may all affect the amount of
cotton dust in the workplace.
Vertical
Elutriator:
It
is used to monitor employee exposure to cotton dust in the workplace. Airs is
drawn into the vertical elutriator at a specified speed, and particles of 15
microns or smaller are collected on a filter. The particles collected are
measured to determine the amount of respirable dust (dust that can get into 4
the lungs) there is in the work area. It is important to realize that other
dusts, such as starch or oil mist are also collected
on
the filter and may contribute to the cotton dust levels.
Fig 2 Vertical Elutriator
Dust
Control Measures:
Monitoring
of cotton dust concentration in the occupational environment
Provide
medical surveillance to the cotton dust exposed workers
Establishing
safe working practices to reduce the exposure level
Training
and education of workers
Engineering
controls to reduce the emission
Use
of dust masks
Preventive
measures to be followed during manufacturing process:
Sustainable conversion of cotton dust
There are a number of ways in which cotton
dust can be disposed of sustainably.
- Biogas production: In his research titled
'Production of Biogas from Willow Dust', RH Balasubramanya states that
willow dust contains traces of wax, cellulose, hemicelluloses and lignin.
It is found that the substances which have C: N ratios of 25:1 are found
to be optimum for biogas production. In willow dust, this ratio is of 30:1
(C: 1 (C: N) and hence is suitable for biogas production.
- Vermicomposting: Considering the organic
nature of cotton dust, with the use of vermicomposting technology and
enzyme technology the cotton dust may be converted into bio-compost.
Vermicomposting is a technology for converting solid organic waste into
highly beneficial and rich compost which can be used as fertiliser to
enhance soil fertility. The worms create a home for millions of
microorganism that help in reducing the toxicity of waste. This is viewed
as the organic, sustainable, and eco-friendly alternative to chemical
insecticides and pesticides which cause harmful effect on the health of farmers.
Cotton uses approximately 25 per cent of the world's insecticides, due to
which large number of farmers die. Therefore, this could be used for
organic farming which would also help in reducing dependence on the costly
and hazardous chemicals and pesticides.
- Fuel for boiler: The dust contains traces
of wax which when burnt releases energy which can be utilised as fuel for
boilers. This would help the industry to save on fuel costs, and also it
is the sustainable reuse of the waste which would otherwise release
obnoxious smell into the environment and if burnt in air, then increases
the carbon dioxide levels of the atmosphere.
General
practices:
- Usage of compressed air
for cleaning purposes should be prohibited when other means of cleaning
are possible. Where blow-down cleaning is done (meaning general cleaning
of the entire room, including the walls and ceilings ventilation ducts),
employees performing the cleaning must wear respirators.
- All other employees not
involved with the blow-down cleaning must leave the area.
- Cleaning of clothing or
floors with compressed air is prohibited.
- Floor sweeping will be
done by vacuum or other methods designed to minimize the breathing of
dust.
- Waste will be handled
by mechanical means. Manual handling should be limited as much as
possible.
- Ventilation systems
should be inspected regularly.
Work
practices during Material handling and cleaning:
- Cotton, Cotton waste
and materials containing cotton dust should be stacked or handled properly
in such a way that will reduce dust level.
- Brooms should be used
properly so that dust will be controlled and vacuum cleaners should be
used wherever dust control is difficult.
- When cleaning machines
with brushes or cloths, the individual doing the cleaning should stroke
the waste from top to bottom as far from the face as possible. Surfaces
should not be beaten or fanned during cleaning.
- Waste should be placed
in the corresponding waste storage container immediately before
accumulating in the floor.
- Waste receptacles or
waste transport containers should be placed in the respective places such
that disturbance creating by any means would be avoided.
- Waste receptacles
should not be overfilled such that material spills to the floor during
storage or transport to the waste godown.
- Spring-loaded cans and
carts should not be used as waste receptacles in order to avoid dust
dispersion during compression of the spring-loaded bottoms.
- When materials such as
laps, sliver cans and roving bobbins are delayed in process or stored for
an extended period in an area where there is a likelihood of significant
dust or lint accumulation, the materials should be covered. The storage
area and the covers should be periodically cleaned to prevent lint and
dust accumulation.
Conclusion:
As
being the largest contributor to the national economical growth, we are giving
atmost emphasis to the textile industry especially in terms of developing high
speed machineries, versatile machines and high quality products. At the same
time we must focus on health conditions of the human involving in the
manufacturing process and environmental conditions. Textile Mills should follow the work procedures to control the cotton dust exposure
to workers. The cotton dust which is creating health hazards to the lakhs of
labours involving in the textile manufacturing process should be controlled by
creating awareness among the workers and by the effective management.
Micro dust in cotton refers to fine particles of dust and impurities that are present in cotton HostingSpell fibers, which can affect the quality of cotton during processing.
ReplyDeleteGreat blog on PP Multifilament Yarn! Its versatility in the textile industry is truly commendable. PP filament yarn, known for its lightweight, high tenacity, and resistance to chemicals, is essential in creating durable geotextiles, ropes, and industrial fabrics. Your insights on its applications highlight its significance. Thanks for sharing this valuable information!
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