Water consumption Water is one of the most important substances on earth. All plants and animals must have water to survive. If there was no water there would be no life on earth. There are two ways in which we can classify our water use. One type is in-stream use; this includes hydroelectric power, boating and swimming, for example. While in-stream activities do not use up the water, they can degrade the water quality through pollution. The other type of water use is the withdrawal of water, and this classification includes household use, industry use, irrigation, livestock watering and thermal and nuclear power. Most withdrawals are consumptions, meaning that the activity uses the water and does not return it to the source. The amount of water that is taken (or withdrawn) from the source is called the water intake, and the amount that is returned is called the water discharge. The difference between the water intake and the water discharge is the amount consumed. Water intake – Water discharge = Consumption The total amount of water that is used is called the gross water use. The difference between the gross water use and the water intake is equal to the amount of water that is recirculated. The recirculated amount is expressed as a recycling rate and is a good indicator of water efficiency. Gross water use – Water intake = Amount recirculated (or recycling rate) Sources of water: Ground Water: Ground water refers to any source of water that lies beneath the soil layer. Ground water can exist in the soil itself or between rocks and other materials. Most communities obtain their water from underground aquifers, or rock formations capable of holding large amounts of freshwater. Only 3 percent of the water on earth is considered freshwater, with a mere 30 percent of that small amount being found as groundwater. Pollution, seawater contamination and overuse threaten this valuable resource. Surface Water: Sources of surface water can include any above-ground collection of water such as rivers, lakes, ponds and oceans. Some sources of surface water are also fed by underground aquifers. Surface water accounts for 80 percent of the water humans use. Ocean Water: Although ocean water makes up nearly 97 percent of all water on earth, it is not a viable source of potable water unless salt and other impurities are removed. Desalination, the process by which salt is removed from water, is a rapidly growing practice. While salt and other microscopic particles can be removed from water in a variety of ways, the most promising method is through reverse osmosis. This process forces saltwater through filters with microscopic pores that remove salt and other microbes. Reverse osmosis requires large amounts of energy, making it a very expensive process.

1. Mawlana Bhashani Science & Technology University
Santosh, Tangail-1902
Department of Textile Engineering
Course Title : Environment & Pollution Control
Course Code : TXE 443
Assignment No : 01
Assignment On : Water Consumption
Date of Performance :07 .04.2019
Date of Submission : 19.04.2019
Submitted by,
Md. Fahimuzzaman
ID: TE 14025
Dept. Of Textile Engineering, MBSTU
Year: 4th Semester: 2nd
Submitted To,
Dr. M. Mahbubul Bashar
Associate Professor,
Dept. of Textile Engineering, MBSTU
Santosh,Tangail-1902

2. Water consumption:
Water is one of the most important substances on earth. All plants and animals must have water to
survive. If there was no water there would be no life on earth. There are two ways in which we can
classify our water use. One type is in-stream use; this includes hydroelectric power, boating and
swimming, for example. While in-stream activities do not use up the water, they can degrade the
water quality through pollution. The other type of water use is the withdrawal of water, and this
classification includes household use, industry use, irrigation, livestock watering and thermal and
nuclear power. Most withdrawals are consumptions, meaning that the activity uses the water and
does not return it to the source.
The amount of water that is taken (or withdrawn) from the source is called the water intake, and the
amount that is returned is called the water discharge. The difference between the water intake and
the water discharge is the amount consumed.
Water intake – Water discharge = Consumption
The total amount of water that is used is called the gross water use. The difference between the gross
water use and the water intake is equal to the amount of water that is recirculated. The recirculated
amount is expressed as a recycling rate and is a good indicator of water efficiency.
Gross water use – Water intake = Amount recirculated (or recycling rate)
Sources of water:
Ground Water:
Ground water refers to any source of water that lies beneath the soil layer. Ground water can
exist in the soil itself or between rocks and other materials. Most communities obtain their
water from underground aquifers, or rock formations capable of holding large amounts of
freshwater. Only 3 percent of the water on earth is considered freshwater, with a mere 30
percent of that small amount being found as groundwater. Pollution, seawater contamination
and overuse threaten this valuable resource.
Surface Water:
Sources of surface water can include any above-ground collection of water such as rivers,
lakes,ponds and oceans. Some sources of surface water are also fed by underground aquifers.
Surface water accounts for 80 percent of the water humans use.
Ocean Water:
Although ocean water makes up nearly 97 percent of all water on earth, it is not a viable
source of potable water unless salt and other impurities are removed. Desalination, the
process by which salt is removed from water, is a rapidly growing practice. While salt and
other microscopic particles can be removed from water in a variety of ways, the most
promising method is through reverse osmosis. This process forces saltwater through filters
with microscopic pores that remove salt and other microbes. Reverse osmosis requires large
amounts of energy, making it a very expensive process.

3. Ice Caps and Glacial Melting:
Of the 3 percent of earth's water considered freshwater, 70 percent of that small amount is
currently locked in glaciers and ice caps. In theory, frozen glacial and ice cap water could be
melted and used, but the amount of energy needed to melt and transport vast quantities of
ice make it economically impractical. Glaciers and ice caps also play vitally important roles in
the regulation of earth's climates and global temperatures, making their preservation very
important.
Water uses and consumption:
Everyday Living
The most common use of water is through drinking. People drink water almost every day and would
not be able to survive without doing so. Water is also used in everyday life for cooking, cleaning,
washing and playing. These activities use on average 90 gallons of water per day for the average
American. Except when asleep, it is rare to go more than a couple of hours without some interaction
with water.
Agriculture
Agricultural use of water is one of the most common uses of water. Not only are crops watered
through various applications of water, but livestock also require daily use of water. Techniques such
as irrigation, spraying, flooding and relying on natural precipitation all aid agriculture. Water is
provided from reservoirs, canals and wells as key sources for agriculture. Fisheries and open water
harvesting of seafood is a further example of how water is a part of agriculture.
Energy
Many often initially think of hydroelectric power generation when considering the use of water in
energy generation. However, the use of water goes far beyond that. Water wheels are still used
around the world to produce mechanical energy. Water is also a critical function in the production of
energy in fossil fuel-based generation plants. The fossil fuels are burned in order to convert water into
steam, which in turn is used to turn the turbines that generate the electricity.
Manufacturing
Water plays a critical role in numerous industries. It is the most common cooling agent for many heat-
intensive industrial applications. It is a common solvent in many chemical processes and is also a
common component in washing and cleaning steps in many processes. Water also is used in
transportation on several scales in industry. Not only are goods transported by ships and barges, but
raw materials are often transported by slurry in many industries, most especially mining. There are
very few heavy industries that do not use water in part of their process.
Textile industry
The textile Industry is in no way different than other chemical industries, which causes
pollution of one or the other type. The textile industry consumes large amount of water in its
varied processing operations. In the mechanical processes of spinning and weaving, water
consumed is very small as compared to textile wet processing operations, where water is used
extensively. Approximately 85% of the water used and discharged from factories is in the wet

4. processing stage. Almost all dyes, specialty chemicals, and finishing chemicals are applied to
textile substrates from water baths. In addition, most fabric preparation steps, including
desizing, scouring, bleaching, and mercerizing use aqueous systems. According to USEPA a
unit producing 20,000 Ib / day of fabric consume 36000 liters of water.
In textile wet processing, water is used mainly for two purposes. Firstly, as a solvent for
processing chemicals and secondly, as a washing and rinsing medium. Apart from this, some
water is consumed in ion exchange, boiler, cooling water, steam drying and cleaning. Textile
Industry is being forced to consider water conservation for many reasons. The primary reasons
being the increased competition for clean water due to declining water tables, reduced sources
of clean waters, and increased demands from both industry and residential growth, all resulting
in higher costs for this natural resource. Water and effluent costs may in the more common
cases, account for as much as 5% of the production costs.
Water usage at textile mills can generate millions of gallons of dye wastewater daily. The
unnecessary usage of water adds substantially to the cost of finished textile products through
increased charges for fresh water and for sewer discharge. The quantity of water required for
textile processing is large and varies from mill to mill depending on fabric produce, process,
equipment type and dyestuff. The longer the processing sequences, the higher will be the
quantity of water required. Bulk of the water is utilized in washing at the end of each process.
The processing of yarns also requires large volumes of water. The water usage of different
purposes in a typical cotton textile mill and synthetic textile processing mill and the total water
consumed during wet process is given in table 1 and table 2 respectively.
Table 1: Water usage in textile mills
Purpose Percent water use
Cotton textile Synthetic textile
Steam generation 5.3 8.2
Cooling water 6.4 -
Demineralised or RO
water for specific Purpose
7.8 30.6
Process water 72.3 28.3
Sanitary use 7.6 4.9
Miscellaneour and fire
fighting
0.6 28.0
Table 2: Total water consumed during Wet processing
Process Percent of Water consumed
Bleaching 38%
Dyeing 16%
Printing 8%
Boiler 14%
Other uses 24%

5. Wide variation is observed in consumption mainly due to the use of old and new technologies
and difference in the processing steps followed types of machines used.
Every textile processor should have knowledge of the quantity of water used for processing.
The volume of water required for each process is tabulated as under:
Table 3: Water Requirements for cotton textile wet finishing operations
Process Requirements in litres/1000 kg of products
Sizing 500-8200
Desizing 2500-21000
Scouring 20000-45000
Bleaching 2500-25000
Mercerizing 17000-32000
Dyeing 10000-300000
Printing 8000-16000
Table 4: Water Requirements for synthetic textile wet finishing operation
Process Requirements in litres/1000 kg of products
Rayon Acetated Nylon Acrylic Polyester
Scouring 17000-34000 25000-84000 50000-67000 5000-67000 25000
Salt bath 4000-12000 -- -- -- --
Bleaching -- 33000-50000 -- -- --
Dyeing 17000-34000 34000-50000 17000-34000 17000-34000 17000-3400
Special
Finishing
4000-12000 24000-40000 32000-48000 40000-56000 8000-12000
The average factory water consumption in Bangladesh is estimated to be around 250 to 300
litres of water per kilogram of fabric produced. This is the equivalent to the daily water use for
two people in Dhaka. For comparison, the global benchmark for fabric production is 100 litres
of water per kilogram. In terms of the overall supply chain for textile garments the water used
in the processing and garment production phase has previously been estimated to be close to
50% of the overall water use.
The effluent discharges from the WDF factories, in particular, are heavily polluted with high
levels of dissolved solids and chemicals. Estimates on the number of factories with Effluent
Treatment Plants (ETPs) vary from 40 to 80% although it is widely acknowledged that many
of the installed plants are poorly designed or not operated in an appropriate and responsible
manner.
Pharmaceutical industry:
Types of water used in Pharmaceutical industry are given bellow:
. 1. Potable Water:
 Used in early stages of chemical synthesis

6.  Used Early stages of Equipment Cleaning
 Sources: Public water supply, wells or combination of > 1 of these
 Must meet Requirements of USEPA (40 CFR 141)
 Seasonal variations in quality may occur and must be considered for treatment before
usage.
2. Purified Water:
 Used as excipients in the manufacturing of pharmaceuticals.
 Used for Equipment Cleaning esp. product contact surfaces of nonsterile chemicals.
 Preparation of bulk chemicals.
 Prepared using potable water as feed.
 Types of Purification: Deionisation, Distillation, Ion exchange, Reverse Osmosis,
Filtration.
 Must meet ionic, organic chemical and microbial requirements.
 Systems that produce, store and circulate water under ambient conditions are
susceptible to biofilms. This can be avoided by frequent sanitization and monitoring.
3. Water for injections:
 Used as an excipient in the manufacturing of potentials.
 Used for Equipment Cleaning esp. product contact surfaces of sterile products.
 Preparation of sterile bulk chemicals.
 Prepared using purified water as feed.
 Method of preparation is multicolumn distillation.
 Must meet ionic, organic chemical, microbial and endotoxins requirements.
 Factors like microbial contamination and endotoxins should be controlled by
circulation, frequent sanitization and monitoring.
4. Bacteriostatic Water for injections:
 Contains added preservatives.
5. Sterile Water for injections:
 Packaged and rendered sterile used for reconstitution of dry powder injections.
6. Sterile water for inhalations:
 For inhalation solutions.
Conclusion
Water is one of the most important substances on earth. All plants and animals must have water to
survive. If there was no water there would be no life on earth. High water consuming economic
activities and population growth are responsible for declining per capita water availability.
Increased consumption more so by the “privileged,” puts further pressure on this diminishing
natural resource. As expected, the availability and mode of use of water varies across the socio-
economic classes within the cities.

7. To conclude, it can be stated that the supply of water in the large cities in Bangladesh is going
to be a serious challenge in the future. The rapid increase in the population in these cities,
depleting water resources and enhanced consumer needs are going to create a difficult situation.
Market-oriented development with new needs in sectors like the entertainment industry, the
building industry, new technologies with increasing water needs, enhanced supply in shopping
malls, and simultaneously, the alarming rise in pollution levels in surface water bodies and
even in groundwater is going to exacerbate the situation. Therefore, an urgent need is felt for a
comprehensive water policy for cities which satisfactorily addresses the growing needs of
citizens.