Textile News, Apparel News, RMG News, Fashion Trends
Industry Insight News & Analysis

Sustainable practices in wet processing of Northern Tosrifa Group, the industry best practice

Bangladesh Textile & Apparel industry is getting greener and sustainable. A number of the green and sustainable LEED certified industries recently been established here aiming to make Bangladesh safest place to produce sustainable textiles and apparel products. However, reducing profitability has been a great concern for the industry. Factories here in Bangladesh is struggling to remain competitive and maintaining global stringent compliance requirements and keeping sustainability intact. However, there are best practices in the industry which could be learning for others. This story tells how a textile company here in Bangladesh as set number of benchmarks for others in terms of achieving sustainability by reducing cost and adding more value by improving quality and reputation. Tosrifa Industries Ltd. is a knit composite mill. The company has implemented a number of sustainable technologies and processes which was thought to be impossible to apply for knit fabric in Bangladesh.

The story is about Tosrifa Industries Ltd., a USBC LEED certified factory of Northern Tosrifa Group. Md. Habibur Rahman, Sr. DGM of Northern Tosrifa Group (Fabric Division), was sharing key aspects of the company in a keynote speech titled “Sustainable Practices in Wet Processing of Tosrifa Industries Ltd.” delivered in ‘The 3rdInternational Conference on Textile & Apparel, ICTA 2018’. The conference was jointly organized by Bangladesh Textile Today with The Textile Institute Bangladesh Section (TIBS) held in BICC, Dhaka on 8th February 2018. Textile Today Industry Correspondent has done the necessary study by visiting the factory. The article reveals the inside story based on the speech of Mr. Rahman given in 3rd ICTA 2018.

Figure: Md. Habibur Rahman, Sr. DGM of Northern Tosrifa Group was one of the keynote speakers in the 3rd ICTA 2018 presenting his company model of achieving a number of industry benchmarks.
Figure: Md. Habibur Rahman, Sr. DGM of Northern Tosrifa Group was one of the keynote speakers in the 3rd ICTA 2018 presenting his company model of achieving a number of industry benchmarks.

Md. Habibur Rahman started his speech quoting a verse of Holy Quran “Eat and drink but waste not by extravagance” then he quoted from Holy Hadith “Don’t waste water, even if you were on the banks of a flowing river” to show the sustainability issue from the point of his belief.

Figure 2: Md Habibur Rahman, DGM, Northern Tosrifa Group (Fabric Division), with Textile Today Industry Correspondent (author of this article) in front of CPB dyeing machine.
Figure 2: Md Habibur Rahman, DGM, Northern Tosrifa Group (Fabric Division), with Textile Today Industry Correspondent (author of this article) in front of CPB dyeing machine.

Expressing the motivation of Northern Tosrifa Group (NTG)’s sustainability practices he said, “From the very beginning of Northern Tosrifa Group we realized that the future trend of the industry will be sustainability. The company also feels that to become sustainable in business it is needed to think about the stakeholders. For Tosrifa Industries the stakeholders’ means not only the buyers and investors, it also means the people who run the industry, as well as the surrounding inhabitations of this area.  Tosrifa Industries Ltd. is very much concern about the environmental impact on the people and the society.”

“Tosrifa industry builds a strong code of ethics of sustainability. Our garment division is already LEED, GOTS, ISO 14001 and REACH certified. Recently it launched ‘Tosrifa Industries Limited (Fabric Division)’ located at Beraiderchala, Ansar Road, Sreepur, Gazipur on 20th November 2017. It is a LEED certified Green project. The whole project is equipped with modern machinery and energy efficient setup,” he continued.

Some sustainable practices of Tosrifa Industries Ltd.:

  1. Singeing instead of bio-polishing
Figure 3: ‘Singing’ instead of ‘bio-polishing’ eliminates water and chemical use and give a better quality, better strong fabric. More importantly it gives a clean healthy environment for workers.
Figure 3: ‘Singing’ instead of ‘bio-polishing’ eliminates water and chemical use and give a better quality, better strong fabric. More importantly it gives a clean healthy environment for workers.

Generally, Bio-Polishing requires huge water and chemicals that takes minimum 1 hour and 50°C to 80ºC temperature. It also adds process loss up to 7-8 percent (sometimes more than 10 percent) which is draining out direct money on the weight of the fabric. Therefore, the total minimum cost of bio-polishing is more than 20tk per kg including process loss. Most importantly bio-polishing reduces the strength of the fabric. Besides this when (bio-polished) enzyme fabric runs on stenter or compacting machines, the dyehouse becomes full of dust that causes health problem for the worker. Citing the above disadvantages of bio-polishing, Mr. Habib said that they have eliminated the bio-polishing process. And now they do mechanical singing instead of that.

Benefits of ‘Singing’ instead of ‘bio-polishing’ are:

  1. Total elimination of water and chemicals
  2. Less weight and strength loss
  3. No dust in finishing and cutting section
  4. Minimize the process loss
  5. Increase production rate up to 1600 kg fabric per hour.
  1. Continuous bleaching
Figure 2: ERBATECH continuous bleaching machine.
Figure 2: ERBATECH continuous bleaching machine.

Tosrifa Industries Ltd. has set an example in applying continuous process in knit fabric bleaching, dyeing & finishing. For achieving successful continuous process proper pre-treatment is a must. SCOUT pad-steam bleaching ranges from German company Erbatech has made it easy for the company. Now Tosrifa Industries can do scouring and bleaching any cellulosic fabric, producing a constant and homogeneous base product for later dyeing or printing.

Pad-steam bleaching achieves a high degree of white with less production costs compared to the traditional discontinuous over-flow technology, amongst many other advantages such as;

  • High reproducibility,
  • Product homogeneity (no tailing),
  • Low fiber loss (no enzymatic bio-polishing),
  • Shiny and improved fabric surface (no pilling),
  • Low water, steam, and power consumption.

Mr. Habib explains told that our factory is using ERBATECH machine, which is user-friendly. In continuous bleaching, the initial investment is high but per unit cost is lower and can sustain economically in long run.

tbl

  1. Cold pad-batch (CPB) dyeing

CPB dyeing attempts the utmost cost-effective and advantageous approach of dyeing cotton with reactive dyestuffs. The elimination of salt addition also supports the minimum energy and water consumptions; hence rendering it more eco-friendly and fixation of dye is also high.

Figure 5: Cold pad-batch (CPB) dye padder from Erbatech in operation in Tosrifa Industries Ltd.
Figure 5: Cold pad-batch (CPB) dye padder from Erbatech in operation in Tosrifa Industries Ltd.

“In the initial stage of CPB dyeing it was very challenging, so our management thought to hire a foreign expert to run the project. However, we were trying to learn the process. Our chemical suppliers and machine suppliers helped us in this regards and finally, we succeeded,” Said Mr. Habib. “In dye bath, there are water, fabrics, and dyestuff. In exhaust dyeing, 60% to 75% dyes are fixed on fabric, residual 25%-40% dyes got hydrolyzed and could not react with fabric due to higher liquor ratio. In CPB dyeing M:L is 1:1, so the dye pickup is up to 95%-97%,” he explained. It saves around 20% dyeing cost. There are some risk to be controlled and we in Tosrifa Industries Ltd. doing it perfectly, he added.

The requirement of CPB dyeing of knit fabric

  1. The pretreatment should be homogeneous and proper.
  2. Absorbency need to be excellent thus it absorbs water below 1 second
  3. pH should be neutral
  4. No residual peroxide (2-3 ppm)
  5. Brightness CI value for dark color 75-80, for light color 80-85

qouteFeatures of CPB dyeing

  1. M:L = 1:1
  2. No steam required
  3. Total elimination of  Salt, hence less TDS in ETP
  4. No anti-creasing agent required. Shiny fabric surface without crease marks.
  5. More lustrous fabric compared to conventional process. Suitable for delicate fabrics.
  6. Around 95% – 97% exhaustion of Reactive Dyes
  7. Less friction as a result less fuzz created on the fabric surface. No need for enzymatic bio-polishing.
  8. Less pressure of effluent in ETP
  9. High reproducibility and minimum re-work,
  10. High flexibility in batch size (from color samples up to 1.000 kg batches).

Challenges of CPB Dyeing

  1. Require good quality combed compact yarn
  2. Lab to bulk reproducibility – need to setup bulk like a lab environment
  3. Difficulties in shade correction
  4. Listing ( left center and right side of fabric shade need to control)
  5. Requires selective types of dyestuff and chemicals (Low to medium substantive dyes needed, need to manage dyes trigonometry)
  6. Applicable only for cellulosic materials

tbl1

CPB can lead the industry towards zero discharge

Experts in the sectorhave told that for 20-ton dyeing it needs 12-14 ton boiler, but in CPB it just needs 2-3 ton capacity boiler. WTP and ETP size need to be half.

  1. Marzan Hossain, CEO of Maxchoice Commerce & Technology told to this reporter that in future when zero discharge will be implemented CPB will be the solution. We know salt (TDS) is the main barrier for being zero discharge. Salt recovery is very expensive. CPB dyeing does not need any salt. It saves the environment and the running cost will be lower and the quality is much better.
  2. Marzan Hossain, added that there is a misconception among the industry that CPB is not suitable for medium to light shade. Woven fabric dyeing is much more difficult than knit fabric dyeing. In the world more than 60% – 70% woven fabric dyed in CPB machine, if they could make it happen why not we? CPB can handle any lot size of shade from 10 kg to above.

Nip dyeing:

Ebrtech padder has Nip dyeing system, so tailing problem is eliminated.

Pneumatic  control:

Ebrtech padder is controlled pneumatically. So listing problem is under controlled.

  1. Continuous Washing

“There is no need for special wash off, while neutralization with acid it washed away unfixed dyes as well. The combined neutralization and wash off starts at 95°C and gradually it degrades to 40°C – 50°C room temperature,” Mr. Habib told. Thanks to the Erbatech machines which are universal in application from high sensitive elastic fabrics to heavy and sturdy technical fabrics. Erbatech SCOUT washing ranges can be used for all main washing processes such as; Preparation (de-oiling) washing before heat setting, washing after dyeing and washing after rotary or digital printing.

Figure 6: Continuous washing machine in Tosrifa Industries Ltd.
Figure 6: Continuous washing machine in Tosrifa Industries Ltd.

Features of continuous washing

  1. No wash-off is used but neutralization
  2. Water consumption 10-12 L/Kg
  3. Less hairiness on fabric
  4. Excellent color fastness to rubbing and wash
  5. Excellent wet fastness
  6. Less chance of color bleeding in yarn dyed fabric washing
  7. No crease mark on the fabric for washing

For 1Kg of Fabric (Wet processing)

tbl2

  1. Steam generation

“The natural gas supply is becoming very uncertain in Bangladesh. The government could not supply it on demand. Therefore, now we are using Natural Husk from paddy as fuel for generating steam from the boiler. We collect it from nearest rice mills and they have ample of stock. However, it is not so economical as compared to gas, but we are replacing it with a sustainable supply of fuel”, Said Mr. Habib. Ash from the boiler is being used as fertilizer, he added.

They also collect condensed steamed water and feedback in the boiler feed water tank, which already has enough heat approximately 70°C to 75°C. Therefore, it consumes less energy to generate steam again. This is another great example of reuse-reduce-recycle.

  1. ETP

“In biological ETP bacteria grows, that eliminates the hazardous chemicals so there is no need of any chemicals. We use dung to grow bacteria. Dung is available in Bangladesh and cost is lower than chemicals. Sometimes it needs slightly acid to control the alkalinity,” Said Mr. Habib. Contamination load on our ETP is very less as we are using continuous processes and CPB dyeing.

ETP-plant
Figure 7: Biological ETP Plant.
  1. Tosrifa Industries do rainwater It has 180000 Liter rainwater collection capacity to soft water reserve tank.
  2. “The building is LEED certified, has enough scope to enter daylight. We set the skylight panel in the roof, which scattered the daylight to the entire shade. Inside of the shade is so bright that it feels there is no roof upon the head,” Mr. Habib added. Using skylight during daytime is saving 360KW/Day.
Figure 8: Natural daylight keeps shiny and brighter dyeing floor.
Figure 8: Natural daylight keeps shiny and brighter dyeing floor.
  1. In the rooftop of Tosrifa Industries, they have put a solar panel that is adding 50KW to the main grid, which helps to fulfill the demand for energy.

Latest Publications

View All