In the textile and dyeing industry, PAC (Poly Aluminum Chloride) It plays a crucial role in industrial wastewater treatment, helping to remove color, organic pollutants, and heavy metals so that wastewater meets standards before being discharged into the environment.
Poly Aluminum Chloride, CAS: 1327-41-9, containing 30-31% Al₂O₃ (powder form), supplied with COA/MSDS B2B upon request.
- PAC is highly effective in coagulating and decolorizing textile dyeing wastewater through various processes.
- Optimal dosage and pH levels should be determined using a jar-test method for each specific type of wastewater.
- The application of PAC contributes to meeting ETP discharge standards and ZDHC targets in the textile industry.
How does PAC (Polyaluminum Chloride) wastewater treatment for textile dyeing work?
Textile dyeing wastewater often contains color, organic matter, and pH that fluctuates between batches. PAC coagulants, by neutralizing electrical charges and creating easily settleable flocs, help reduce color, turbidity, and SS over a much wider operating pH range than traditional alums — actual effectiveness depends on jar-testing on the specific wastewater source.
The process of treating textile dyeing wastewater with PAC is carried out in stages.
Desize/scour/bleach/dye/rinse/finish for different wastewater types; PAC is usually added at ETP flocculation-coagulation After collection, do not refill or change the dye on the dyeing line. Water with strong colors and high COD requires a separate jar test. Lab reactive (for reference) has been recorded with a range of ~160–220 mg/L depending on the color. Not a factory SOP; confirmed by jar-test on a real sample. Reference case: ETP Binh Duong Textile.
Distinguishing between PAC powder (30-31% Al₂O₃) and PAC liquid (10-17% Al₂O₃)
Powdered PAC (~30–31% Al₂O₃) is compact for storage and transport; it must be diluted before dosing. Liquid PAC (~10–17% Al₂O₃) is convenient for metering but contains more water. Textile ETP is selected according to the pump, tank, and dosing frequency — always convert the dose to % Al₂O₃ on the COA. Definition/Basic dilution: What is PAC / how to mix it.
Instructions for performing jar tests to optimize PAC dosage.
Jar tests are mandatory when changing batches of chemicals/fabrics: simulates fast-slow stirring-settling, comparing color/turbidity across dosage and pH ranges. Doses on paper are indicative; discarding jar tests leads to chemical waste. See Jar-Test Guide: 7 Errors before locking the metering pump.
Common problems encountered when using PAC in textile dyeing wastewater treatment and how to fix them.
Although PAC is an effective solution, improper operation can lead to problems such as poor coagulation efficiency, treated wastewater remaining colored, or high turbidity. Some common errors include:
- Inaccurate PAC quantification: Using too little or too much PAC will both reduce its effectiveness. Too little will not create enough floc, while too much can cause re-stabilization of the particles.
- pH control is not yet optimal: Although PACs work over a wide pH range, each type of wastewater has its own optimal pH range for PACs to be fully effective.
- Improper mixing technique: Fast or slow mixing processes, or insufficient mixing time or intensity, will affect the formation and development of floc.
- PAC quality is not guaranteed: Using low-quality products or products unsuitable for the type of wastewater.
To address this, regular jar tests are necessary to determine optimal dosage and pH, check the quality of incoming PAC, and ensure the mixing equipment is functioning properly. For more information on effective PAC usage, please refer to [link/website]. Instructions for using Poly Aluminium Chloride chemical.
How does PAC contribute to meeting the ZDHC ETP standard in the textile dyeing industry?
PAC is a chemical FTP, supporting wastewater treatment compliance — not a substitute for MRSL transfer chemicals. When the brand requests color treatment documentation, the chemical name, COA/MSDS lot number, and dosing location are required. Factory checklist: ZDHC textile dyeing implementation.
What do basic PAC specifications include?
| Targets | Unit | PAC Powder (standard) |
|---|---|---|
| CAS | 1327-41-9 | |
| Al₂O₃ content | % | ~30–31 (according to lot COA) |
| Alkalinity (Basicity) | % | 40 - 90 |
| pH (1% solution) | 3.5 - 5.0 | |
| Insoluble matter content | % | ≤ 0.5 |
| Chloride content (Cl⁻) | % | ≤ 8 |
Note: The above specifications may vary depending on the manufacturer and the specific standards of each type of PAC.
What is the recommended PAC dosage for textile dyeing wastewater?
| Wastewater type/Process | PAC dosage (mg/L) | Optimal pH range |
|---|---|---|
| Laundry/bleaching wastewater | 50 - 150 | 6.0 - 8.0 |
| Dyeing wastewater (basic colors) | 100 - 300 | 6.5 - 7.5 |
| Dyeing wastewater (dark/complex colors) | 200 - 450 | 6.0 - 7.0 |
| ETP (Enhanced Wastewater Treatment Plant) | 80 - 250 | 6.5 - 7.8 |
*This is an initial guideline dosage. Accurate determination requires a jar test on actual wastewater samples from the plant.
Frequently Asked Questions about PAC in Textile Dyeing Wastewater Treatment
Can PAC completely remove color from textile dyeing wastewater?
PACs are effective at decolorizing many reactive/direct dyes, but "absolute decolorization" depends on the initial concentration, dye type, dose, and pH. Biological treatment or other steps are often necessary when dyes are highly stable/COD soluble.
What are the main differences between PAC and aluminum sulfate in wastewater treatment?
PAC (Poly Aluminium Chloride) is an inorganic polymer with a more complex chemical formula than aluminum sulfate. PAC has better coagulation efficiency, especially over a wide pH range and at low temperatures, creating larger flocs that settle faster and cause less reduction in the pH of the treated water compared to aluminum sulfate.
How can I determine the optimal PAC dosage for my textile dyeing wastewater?
The best and most essential method is to perform a jar test on actual wastewater samples. This helps you find the optimal PAC dosage and pH to achieve the desired effluent quality at the lowest cost. The jar test should be repeated whenever there are changes in the production process or the type of dye.
Is PAC safe for the environment when used?
PAC is considered safe when used in the correct dosage and procedure. This product helps remove hazardous pollutants from wastewater, minimizing the impact on the natural environment. However, the discharge of sludge after coagulation must be handled according to current regulations.
Is pH adjustment necessary before adding PAC to textile dyeing wastewater?
Although PAC can operate over a wide pH range, adjusting the pH to an optimal range (typically 6.5-7.5 for many types of textile wastewater) before adding PAC can enhance coagulation efficiency, reduce the amount of chemicals needed, and improve effluent quality. A jar test will help determine this optimal pH.
Should powdered or liquid PAC be used to treat textile dyeing wastewater?
The choice between powdered and liquid PAC depends on several factors such as wastewater volume, storage space, existing dosing system, and operating costs. Powdered PAC (30-31% Al₂O₃) is generally more cost-effective for transporting large volumes and offers more compact storage. Liquid PAC (10-17% Al₂O₃) is more convenient for smaller-scale treatment or when greater dosing flexibility is required.
Loc Thien proudly offers high-quality PAC (Polyaluminum Chloride) to meet all industrial wastewater treatment needs. Learn about PAC Tenor 31% from China or PAC Viet Tri 31% To optimize your wastewater treatment process, contact our hotline at (+84) 979 891 929 for detailed advice!
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