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NGO’s color removal solution is designed to remove over 95% of all colors, including reactive dyes.
The water environment in many industrial parks is under heavy pressure from textile dyeing and industrial laundry wastewater that has not been thoroughly treated. Local people have often seen rivers turn pitch black and aquatic life die off in large numbers because of toxic chemicals discharged directly from factories. Environmental authorities are getting tougher, ready to fine violating businesses up to billions of dong, or even suspend their operations. The pressure to protect the environment has never been greater for textile dyeing and industrial laundry businesses.
It is estimated that the textile dyeing process discharges a very large volume of wastewater, from 114 – 394 m3/tonne of fabric; dyeing needs 12 to 65 liters of water per meter of fabric and discharges 10 to 40 liters. Textile dyeing wastewater is highly diverse and complex. Based on calculations from the chemicals used, such as dyes, surfactants, electrolytes, sequestering agents, wetting agents, pH-adjusting agents, starch, enzymes, oxidizing agents …, there are already hundreds of characteristic chemicals, such as dissolved substances and heavy metals.
Many textile dyeing and industrial laundry businesses are searching for a solution that is both effective and economical. The good news is that, with the development of wastewater treatment technology, there are now comprehensive textile dyeing wastewater treatment solutions that help businesses comply with regulations easily, while protecting the environment and optimizing long-term operating costs.
I. Composition and characteristics of textile dyeing wastewater
Textile dyeing wastewater contains the following main pollutants: high temperature; impurities released from fabrics and fibers such as grease, nitrogen compounds, pectin and dirt clinging to the fibers; and chemicals used in the process such as sizing starch, H2SO4, CH3COOH, NaOH, NaOCl, H2O2, Na2CO3, …, dyes, auxiliaries, wetting agents, color-fixing agents and detergents. The amount of chemicals used depends on the fabric type and color, and they mostly end up in the wastewater of the production stages.
1. Pollutants and characteristics of textile dyeing wastewater
Stage | Pollutants in the wastewater | Wastewater characteristics |
Sizing, desizing | Starch, glucose, carboxymethyl cellulose, polyvinyl alcohol, resins, fats and waxes | High BOD |
Scouring, boiling-off | NaOH, waxes and grease, ash, soda, sodium silicate and fiber waste | High alkalinity, dark color, high BOD |
Bleaching | Hypochlorite, chlorine-containing compounds, NaOH, AOX, acids, … | High alkalinity, accounts for 5% of BOD |
Mercerizing | NaOH, impurities | High alkalinity, low BOD |
Dyeing | The main dye types include vat, disperse, reactive, direct, acid, cationic and acid dyes, and metal salts | Very high color, fairly high BOD (6% of total BOD), high TSS |
Printing | Pigments, starch, oil, clay, metal salts, acids, … | High color, high BOD and grease |
Finishing | Traces of starch, animal fat, salts | Slightly alkaline, low BOD, small volume. |
Industrial laundry | Regular washing or denim washing | High color, low BOD |
(Source: Biological Wastewater Treatment Technology – Assoc. Prof. Dr. Luong Duc Pham)
2. Characteristics of textile dyeing wastewater at some factories in Vietnam
Parameter | Unit | Woven cotton goods | Knitted blended goods | Wool weaving | Yarn |
Wastewater | m3/tonne of fabric | 394 | 264 | 114 | 236 |
pH | – | 8 – 11 | 9 – 10 | 9 | 9 – 11 |
TSS | mg/l | 400 – 1000 | 950 – 1380 | 420 | 800 – 1300 |
BOD5 | mg/l | 70 – 135 | 90 – 220 | 120 – 130 | 90 – 130 |
COD | mg/l | 150 – 380 | 230 – 500 | 400 – 450 | 210 – 230 |
Color | Pt – Co | 250 – 600 | 250 – 500 | 260 – 300 | – |
(Source: Faculty of Environment – Hanoi University of Natural Sciences, 2004)
3. The composition and properties of textile dyeing wastewater are presented in the following table:
Parameter | Unit | Results | ||
Reactive dye wastewater | Sulfur dye wastewater | Bleaching wastewater | ||
pH | – | 10 – 11 | >11 | >12 |
COD | mg/l | 450 – 1,500 | 10,000 – 40,000 | 9,000 – 30,000 |
BOD5 | mg/l | 200 – 800 | 2,000 – 10,000 | 4,000 – 17,000 |
Total N | mg/l | 5 – 15 | 100 – 1,000 | 200 – 1,000 |
Total P | mg/l | 0.7 – 3 | 7 – 30 | 10 – 30 |
SS | mg/l | – | – | – |
Color | Pt-Co | 7,000 – 50,000 | 10,000 – 50,000 | 500 – 2,000 |
Turbidity | FAU | 140 – 1,500 | 8,000 – 200,000 | 1,000 – 5,000 |
(Source: Faculty of Environment – Ho Chi Minh City University of Technology)
In essence, textile dyeing wastewater typically has a high temperature, high color, pH >9, and high BOD and COD. In addition, wastewater from the textile dyeing industry contains some chemicals with heavy metals and toxic components that can not only kill aquatic organisms but also directly affect human life.
II. Textile dyeing wastewater treatment technologies in common use today, and NGO’s solution
- Physicochemical treatment (coagulation/flocculation) combined with filtration;
- Physicochemical treatment combined with aerobic biological treatment, or the reverse order;
- Physicochemical treatment, aerobic biological treatment and physicochemical treatment combined;
- Physicochemical treatment, biological treatment and filtration (sand or activated carbon filtration).
Flow diagram of the current textile dyeing wastewater treatment technology:
Overall, the conventional technologies currently applied to textile dyeing wastewater treatment still pose many difficulties for businesses, for example:
- Chemical treatment mostly removes only disperse dyes; more complex dye components such as reactive and vat dyes usually cannot be removed completely.
- Operating costs are high if a lot of chemicals are used. Chemical dosing is especially difficult for the coagulation–flocculation step or Fenton, because production is order-based and the dye composition and pollutant concentration of the wastewater fluctuate constantly with each order.
- Biological systems are usually large and need a lot of space.
NGO’S BREAKTHROUGH COLOR TREATMENT SOLUTION
III. Real case studies in Vietnam
At Saitex Dong Nai, the factory has applied a ZERO DISCHARGE (no wastewater discharge) solution for its denim wastewater treatment system with a capacity of 1,000 m3/day, using advanced technologies including: BIOLOGICAL TREATMENT – ELECTROCOAGULATION – UF & RO FILTRATION
- 98% water recirculation
- Payback period for the entire system ~ 2 years
- No periodic water quality monitoring with the authorities is needed because there is no discharge
Details of the Saitex system at
https://style-republik.com/saitex-nha-may-san-xuat-jeans-tac-dong-moi-truong/
IV. Frequently asked questions
Wastewater from industrial laundries has less color than textile dyeing wastewater, but it also needs to be treated just as strictly. This type of wastewater contains many surfactants (detergents, soap), bleaching agents, grease and dirt from fabrics. These substances cause high organic pollution (BOD, COD) and foaming, and harm water sources if discharged directly.
Yes. If the treated water meets a high standard, the business can reuse it for suitable purposes. Typically, water that has passed through a textile dyeing treatment system and reaches Grade A (the highest standard) can be used to water green areas on the premises, wash workshop floors, or cool machinery. Reuse saves on clean water costs and reduces the volume of wastewater discharged to the environment.
NGO International applies modern technology to ensure that the effluent meets strict standards. The system is automatically controlled, energy-saving and environmentally friendly. The flexible design suits medium and large businesses. Professional after-sales service helps the system run stably over the long term.
The investment cost of a system depends on the flow scale and the technology applied, so it varies widely. Businesses should contact a consulting provider to get a specific quotation based on their actual needs.
Vietnamese law has many strict provisions on this issue. Specifically, QCVN 40:2025/BTNMT is the national technical regulation on industrial wastewater (which also applies to the textile dyeing industry from 1 September 2025, replacing QCVN 13-MT:2015/BTNMT) and sets the maximum permitted limits for pollutant parameters before discharge to the environment. In addition, the Law on Environmental Protection 2020 and its guiding decrees (for example Decree 45/2022/ND-CP on administrative penalties in the field of environmental protection) impose very heavy penalties on violating businesses
Video: Textile dyeing wastewater treatment station
See more at:
https://shopngoenvironment.com/product-category/san-pham-cong-nghiep/thiet-bi-loc/
https://shopngoenvironment.com/product/mang-ro-xu-ly-nuoc-thai/
https://shopngoenvironment.com/product/thiet-bi-mang-loc-e-mbr/
https://shopngoenvironment.com/product/mang-loc-mbr-x/
https://shopngoenvironment.com/product/thiet-bi-keo-tu-dien-phan-ec/
For advice on color treatment solutions or textile dyeing wastewater treatment systems for factories and industrial laundries, contact us on +84 24 7300 0890, or send an email to office@8ngo.com
Talk to an NGO engineer
Free survey and consultation. Send us your wastewater type (industrial or domestic), flow rate (m³/day), influent analysis results if available and required effluent quality; an NGO engineer will propose a suitable technology and a realistic quotation.
Offices in Hanoi and Ho Chi Minh City · +84 24 7300 0890 · office@8ngo.com
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See also: Industrial Wastewater Treatment — NGO Environment’s comprehensive solution.
