Industrial Water Footprint: Case Study on Textile Industries
57
has been given in Table 1. The unfixed dye is removed from the fabric by performing
several wash cycles and is aided by adding detergents.
These chemicals affect the quality of water as they are presently more than the
permissible limit. The TDS, TSS, BOD, and COD levels are found to be higher
for woven fabric than knitted fabric. Also, the presence of dye imparts color to the
grey water which inhibits the penetration of the sun’s rays to the living organism,
when it is directly disposed of in a water body. This decreases the photosynthesis of
aquatic organisms and that leads to a decrease in the dissolved oxygen (DO) level of
the corresponding water body. Proper treatment techniques have to be performed to
reduce these contaminants as they are considered to be hazardous to the environment.
14.2 Water Utility: Other Operations
There are several places in the industry other than the process operation, where
water is required. In the textile industry, certain operations require water with at
most quality, i.e., demineralized water. Water from obtaining from surface resources
(which is blue water) contains a high amount of salts, which results in the hardness
of water (hard water). To remove the hardness from the water, the reverse osmosis
(RO) mechanism is employed in most of the industry. About 8% of the overall
water consumption is contributed by this RO process to produce water with minimal
hardness (soft water). Another important operation carried out in the industry that
consumes water is cooling. About 6% of the water consumption is attributed to
the cooling operation. Cooling is done to maintain the temperature and humidity in
the textile industry. The textile industry might run all year round and the humidity
varies every day. Depending on the humidity of air present in the textile industry, the
absorption or release of moisture from the cotton fiber can be determined. This cycle
if not properly maintained will affect the characteristics of the cotton textile produced
in the industry. The specific water consumption of cooling operation lies in the range
of 8–12 L/kg product. To maintain the temperature, i.e., to heat the water baths in the
wet processing unit, steam is used. Steam is produced by heating water in a boiler
to a temperature greater than 100 °C. About 5% of the overall water consumption is
attributed to this operation. The water used to produce steam should have lesser salts
because with time these salts settle at the bottom of the boiler leading to inefficient
heating. This phenomenon is called scaling and in extreme case scaling may even
lead to boiler explosions. So, the water used in this process should be demineralized
before utilizing it for steam generation. There is a considerable amount of water
that is lost in the steam generation process via evaporation. Also, water is lost via
transmission from one place to another due to the presence of faulty lines or leaks
in the pipeline. Roughly about 1% of the overall water usage is lost because of the
above-mentioned problems. Sanitary uses consume about 6% of the overall water
usage of the textile industry. Sanitary works include cleaning and washing of the
equipment’s used for performing various operations in the textile industry. Also,
water used for using and cleaning the toilet comes under this fraction of water usage.
57
has been given in Table 1. The unfixed dye is removed from the fabric by performing
several wash cycles and is aided by adding detergents.
These chemicals affect the quality of water as they are presently more than the
permissible limit. The TDS, TSS, BOD, and COD levels are found to be higher
for woven fabric than knitted fabric. Also, the presence of dye imparts color to the
grey water which inhibits the penetration of the sun’s rays to the living organism,
when it is directly disposed of in a water body. This decreases the photosynthesis of
aquatic organisms and that leads to a decrease in the dissolved oxygen (DO) level of
the corresponding water body. Proper treatment techniques have to be performed to
reduce these contaminants as they are considered to be hazardous to the environment.
14.2 Water Utility: Other Operations
There are several places in the industry other than the process operation, where
water is required. In the textile industry, certain operations require water with at
most quality, i.e., demineralized water. Water from obtaining from surface resources
(which is blue water) contains a high amount of salts, which results in the hardness
of water (hard water). To remove the hardness from the water, the reverse osmosis
(RO) mechanism is employed in most of the industry. About 8% of the overall
water consumption is contributed by this RO process to produce water with minimal
hardness (soft water). Another important operation carried out in the industry that
consumes water is cooling. About 6% of the water consumption is attributed to
the cooling operation. Cooling is done to maintain the temperature and humidity in
the textile industry. The textile industry might run all year round and the humidity
varies every day. Depending on the humidity of air present in the textile industry, the
absorption or release of moisture from the cotton fiber can be determined. This cycle
if not properly maintained will affect the characteristics of the cotton textile produced
in the industry. The specific water consumption of cooling operation lies in the range
of 8–12 L/kg product. To maintain the temperature, i.e., to heat the water baths in the
wet processing unit, steam is used. Steam is produced by heating water in a boiler
to a temperature greater than 100 °C. About 5% of the overall water consumption is
attributed to this operation. The water used to produce steam should have lesser salts
because with time these salts settle at the bottom of the boiler leading to inefficient
heating. This phenomenon is called scaling and in extreme case scaling may even
lead to boiler explosions. So, the water used in this process should be demineralized
before utilizing it for steam generation. There is a considerable amount of water
that is lost in the steam generation process via evaporation. Also, water is lost via
transmission from one place to another due to the presence of faulty lines or leaks
in the pipeline. Roughly about 1% of the overall water usage is lost because of the
above-mentioned problems. Sanitary uses consume about 6% of the overall water
usage of the textile industry. Sanitary works include cleaning and washing of the
equipment’s used for performing various operations in the textile industry. Also,
water used for using and cleaning the toilet comes under this fraction of water usage.