Textile Waste Water Treatment
by Abdul Rahim
Khatri, Technical sales and Marketing, Chemi Colour Enterprises.
even if you are on the bank of a running stream.
” Holy Quran ,
Sunan Ibn Majah 425
Water is one of the many blessings which mankind,
unfortunately, takes for granted. We will never truly understand
the real importance of water until the well has run dry.
The textile industry is a major contributor to the economy in
many nations and generates substantial employment opportunities.
Alongside many other inputs, water is perhaps one of the most
essential inputs in textile processing. Indeed, one of the
biggest challenges we face today has to do with a growing water
scarcity and a potential water crisis unfolding in the future.
Textile wet processing is one of the largest segments within
the textile chain and the sheer volumes of water consumed within
this segment alone far exceed all other processes.
These fast approaching challenges are not limited to
sustainably, managing existing water resources or reducing water
consumption alone. Certainly, a growing concern is effluent
discharged from untreated wastewater given its high chemical
load, which contaminates not only rivers and surface water but
also underground aquifers and disturbs the delicate balance of
the natural ecosystem.
A colored river which contains high amounts of hazardous
chemicals results in a loss of biodiversity in fish and marine
life as well as various species of plants and corals. It has
further negative effects downstream when that water is used for
human or animal consumption as well as for agriculture since it
contains large amounts of COD and BOD hence it clogs the pores
of the soil in fields and results in loss of soil fertility.
Since the global textile industry itself has now fully
shifted from the Western to the Eastern part of the world, we
should pay attention to the experience of developed nations that
had experienced this industrial phase decades ago and have now
estimated the ‘true cost’ to the environment, to their citizens,
and to their future generations.
textile industry is a heavy consumer of water and it ranks
highly among the top ten water consuming industries that exist
around the world today.
Pakistan is considered one of the major cotton producing
countries in the world and caters not only to its huge local
demand for cotton fabric but also to the international markets
for various brands and big names in fashion. As a result, a wide
number of dyeing and printing units have propped up throughout
Pakistan has historically held surplus amounts of water but
in more recent times, due to rising population pressures,
effects of global warming, and various other human and
technological changes happening around the globe, our natural
resources are depleting at a very rapid rate.
While agricultural usage still accounts for the most amount
of water consumed among other industries, next in line in terms
of water consumption certainly is the textile industry. The
failure is on part of the state, that needs to take regulatory
environment measures, issue proper guidelines and enforce strict
standards. Additionally, each and every industry should relate
to and feel responsible for nature as well as for consuming the
water and throwing the contaminated water.
In current times, the major concerns and challenges that
exist within the textile industry revolve around bringing
further improvements and production efficiencies to consume less
water in terms of cost efficiency. Equally important, however,
is to reduce hazardous chemicals since the textile industry
takes a heavy toll on the environment and the dyeing process is
well known to be a major source of water pollution.
According to the United Nations Environmental Program
(UNEP-2010), every year 400-500 million tons of deadly chemicals
like cyanide, sulphur and other harmful substances are
discharged in water. Source: (European Scientific journal Sept
2014 special edition, volume 2)
Since the industry has undergone a profound shift in
developed countries, the prevailing laws, regulatory controls,
and other such measures are designed to be stricter and less
permissible about untreated wastewater discharge compared to
developing nations where laws are often weak, unenforced, and in
some cases even non-existent due to lack of knowledge and
awareness surrounding public health and environmental issues.
Most textile effluent is discharged into the surface water
such as river and lakes, either directly or through municipal
sewers. The main issue has to do with the wide variety of
chemicals that it contains.
To ensure social responsibility, organizations should look
into the concerns of their staff and carefully assess health
risks to not only improve the safety level of their employees
but also to uphold moral standards and be contributive to the
wider textile community. More than 3600 dyes exist today with
the addition of more than 8000 chemicals being used in various
manufacturing processes. Many of these chemicals are poisonous
and damaging to human health directly or indirectly.
The daily water consumption of an average size textile unit
while producing about 8T/day of fabric, may be up to 1.6 Million
litres. Specific water consumption for dyeing varies from 30-70
litres per kg of cloth depending on the type of the dye. Dyeing
section only contributes to about 25% of the total wastewater.
The World Bank estimates that 20-30% industrial water
pollution comes from textile dyeing and finishing plants. Mills
discharge millions of gallons of this effluent as hazardous
toxic waste consisting of various dyes, acids, soaps, heavy
metal like copper, arsenic, lead cadmium, mercury, nickel,
cobalt and certain auxiliaries which all collectively make the
effluent highly toxic.
Moreover, the high pH and temperature are also damaging for
the streams and rivers. The colloidal matter present along with
colours and oily scum increases the turbidity and gives the bad
appearance that prevents photosynthesis and depletes the oxygen
transfer mechanism at the air-water interface.
Prevailing situation of water pollution is a major cause of
human illness these days. About 40% of the synthetic organic
colours contain bound chlorine known as “Carcinogen Compounds”.
Chlorine is commonly known as a disinfectant. These carcinogen
chemicals in the effluent disturb the bacterial growth or once
they are evaporated in the air which human breathe or absorb
through the skin and show up as allergic reactions causing harm
to the immune system of living species.
To define the term BOD and COD and its impact on aquatic
life, it is important to first understand the concept.
The depletion of Oxygen in water has a negative impact on
water life. BOD is Biological Oxygen Demand and measured as mg/l
or ppm, it is the measure of the number of organic Carbons
present that bacteria can oxidize. COD or Chemical Oxygen Demand
is the total measurement of all chemicals in the water that can
In general, the textile water discharge has a higher level of
COD than BOD. The COD is less affected by the usual effluent
treatment process.Another term which is been used as “TOC” Total
Organic Carbon and it serves as an alternative to BOD and
COD.All these can be measured through pre-defined format of
In order to reduce water pollution, some measures have been
taken for the betterment of life.
There are many techniques and processes to treat textile
effluent with primary importance of reducing water pollution by
optimizing processes so that fewer contaminants are discharged.
Some of the terms that should be understood here which are
being used in the treatment process of water include:
- ETP: Effluent treatment plant used to treat the
- INFLUENT: Untreated industrial wastewater.
- EFFLUENT: Treated industrial waste products.
- SLUDGE: Solid part separated from wastewater by
Awareness to go green
Eco-friendly clothing concepts are emerging in line with
consumer preferences with several apparel manufacturers opting
to use organic cotton (pesticides free) along with using GOTS
(Global Organic Textiles Standard) approved dyes and chemicals.
At the same time, a seemingly contradictory preference has been
for richer variety and versatile textile colour palettes driven
by fast fashion. It seems a near impossibility to produce
fabrics that have no colour.
The preventive measures are already in consideration about
the ongoing awareness of environment on part of the dyes and
chemical manufactures even up to the extent of designing future
machines, including ‘air dyeing technology’ which is already in
use now produced by a Dutch company Dyecoo.
This company has introduced a machine in collaboration with
Nike for a commercial setup in Taiwan. The process, which Nike
has dubbed ColorDry, reduces dyeing time by 40%, energy use by
about 60%. Lowering the impact of the carbon footprint for the
manufacturing of textile goods.
Nike expects Dyecoo’s supercritical fluid Carbon dioxide or
“SCF” CO2 dyeing technology to have a particularly positive
impact in Asia, where much of the worlds textile dyeing occurs.
This technology is so far limited to disperse dyeing of
polyester, where 95% water is being conserved.
Chlorine was known to be the most known bleaching element at
one time in the textile industry for the bleaching process.
Since it has been realized that chlorine adversely affects the
environment, the industry has shifted to the alternate of
Oxidation bleaching i.e Hydrogen per Oxide. It is a relatively
safer option compared to the older approach. Ozone Bleaching is
also in consideration but its economic viability is questionable
and therefore, it has not been widely adopted for the process.
Today, more focus is being given for more natural finishes
made of bees’ wax, Aloe Vera and Vitamin A, but many finishes
have yet to be identified with safer alternatives particularly
the application of fluorocarbons for flame retardants and other
finishes of oil and water repellency.
The PVA (Polyvinyl Alcohol) is still been used for sizing but
alternative can be potato starch or CMC (Carboxy Methyl
Cellulose) as both are used in food and are chemically inert and
The studies are being conducted for developing dyes that
ensure highest safety standards from manufacturing to the point
of application. The German Consumer goods ordinance in 1997,
identified certain aromatic amines which were being used for the
synthesis of certain dyestuff that was either completely banned
or with very strict prescribed limits to be detected in the
final article. These aromatic amines have potentially adverse
effects on mankind with certain acute and chronic toxicities.
Sulphur dyes have the limitation of using sodium sulphite,
notoriously harmful for the environment, hence companies have
looked into safer options of producing liquid Sulphur ready to
The vat dyes are generally safer in terms of reconverting
back into their water-insoluble form in the fibre. They are less
likely to wash out without any harmful effect, but manufacturing
of these dyes and as well in application usage of Sodium
hydrosulfate is of a big question mark.
The reactive dyes are by far the surest and safest option for
cotton clothing but research is supportive of producing new
products with Vinyl Sulphone chemistry than to counterpart of
reactive dyes based on reactive groups consisting of Chlorine
and Florine, AOX compounds. Sodium chloride is widely being used
during reactive dyes, which increases the salinity of the water
been discharged from dye houses effluent hence issues of
corrosion of concrete and pipes.
The issue of pollution is of serious concern, the companies
are feeling responsible and working towards sustainability with
the emergence of the concept of ZDHC (Zero Discharge of
A step towards sustainability many fashion retailers have
joining hands for a safer environment in textile chain moreover
due diligence of awareness and regulations are pushing for the
step up of ETP plant for all processing houses. This shift in
the textile trades paradigm means that in future it is likely
that the operation of an ETP will be integral to sustain
business in the competitive world market.
ZDHC is concept and approach towards a measure of
sustainability for manufacturing the goods with a high level of
safety at all stages. Certain chemicals are being strictly
prohibited for use during the manufacturing process so it does
not have any impact in the chain from the beginning till it
reaches the final consumer.
This roadmap of ZDHC defines the safest way of achieving the
new standard of environmental performance for the Global apparel
and footwear industry.
The fashion retail like H&M, Levi-Strauss, M&S, Adidas, Nike
etc. is part a greater effort towards eco-friendly clothing that
does not harm the environment.
A further effort from the industrial side, responsible
companies are moving towards the concept of ZLD (Zero Liquid
Discharge) where during the production of either any industrial
chemicals or dyes or even final textile effluent from dyeing
mills are treated and reused so that it cannot pollute the
natural environment and also conserve water.
This treatment of water developed to completely eliminate all
liquid discharge from a system. The goal is to reduce the
volumes of wastewater that requires additional treatments to
make it clean enough to be reused.
Since past several years sustainability has been adopted by
many companies in the textile chain, as well as in other
industries as a target in order to improve existing process and
products with the aim to guarantee environmental care solutions.
Sustainability is one of the main drivers for innovation. And
accepting this challenge, companies will receive and give a lot
JAY Chemical Industries Limited. aims to practice right,
behave ethically, act with integrity, live and breathe the
values. Their philosophy supports the approach to sustainability
management. To secure a sustainable future they have taken into
consideration the Economic, Environmental and Social impact as
to contribute towards nature and society.
One of the main production facility of JAY Chemical
Industries is operating on ZLD – “zero liquid discharge” since
the mid of 2016.
Over 1 Million litres per day of wastewater is recycled or
reused into the process. Several by-products are recovered from
the waste and are either used in-house or commercially offered
to other industries. This project has already attracted an
initial investment of over US$ 10 million.
A step forward has been towards the generation of “renewable
energy” to reduce the carbon footprints. Where the company has
invested about USD 9 million for Solar and Wind projects and
generating about 17 Million Units of Power per Annum.
The importance of water as a precious resource is globally
recognized and the quality of life depends on the ability to
manage available water resources in the greatest interests of
The collaborators are required to work on an objective to
optimize and implementation of the concept of 3R in the whole
chain of textile i.e. from dyestuff chemical manufacturer till
the final end of the chain.
According to an article in business week Issue of June 2005,
the population that is allergic to chemicals will grow to 60% by
the year 2020. The R&D efforts to be stepped up “Value Product”
in a “Value Environment” we all need to join in a race to go
This aspect should also be considered by national and local
governments to create and promote safer environments, in
addition to regulatory checks and measures that are enforced
since we all owe our planet and want to leave it intact for
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(2013). Textile Dyes, Dyeing Process and Enviromental
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Impacts of Textile Azodyes.
- Textile Dyeing Industry an Enviromental Hazard Natural
Science Vol 4 No 1. (2012).
- USA, APHA, AWWA, & WEF. (19th Edition). Standard Method
for Examination of Water & Waste Water.
- Wasif, A., & Kone. (1996). Textile Processing and
Enviromental Consequences. Textile and Engineering
- www.greenrivertech.com.tw. (n.d.). Retrieved from