By Senjie Filter Press Engineering Team · Last updated: 2026-09-14
Quick answer: A chamber filter press dewaters textile dyeing wastewater sludge from 2 to 4% solids to a 60 to 70% moisture cake; a membrane press reaches 50 to 55%. A 1,000 m³/day dyeing plant produces 400 to 800 kg of dry solids per day and typically needs one 1000 mm press with 50 to 80 plates.
Dyeing mills in Vietnam, Bangladesh, India and Indonesia treat 500 to 5,000 m³ of effluent per day. Coagulation with alum, PAC or ferric chloride creates a wet chemical sludge that must be dewatered before it leaves the site. This guide gives sludge quantities, plate sizing, cloth selection and realistic cake moisture. Machine specifications are on the chamber filter press page.
What kind of sludge does a textile dyeing ETP produce?
A textile dyeing effluent treatment plant (ETP) produces a chemical sludge of metal hydroxide flocs, dye residue, fibre lint and sizing agents at 2 to 4% solids after thickening, which filters 5 to 10 times more slowly than a mineral slurry.
Coagulant dosing of 200 to 600 mg/L of alum or PAC, or 300 to 800 mg/L of ferric chloride, forms 0.2 to 0.5 kg of hydroxide floc per m³ treated. Removed suspended solids, colour and COD add another 0.2 to 0.3 kg/m³. Expect 0.4 to 0.8 kg of dry solids per m³ of effluent in total, more when lime is dosed.
Biological sludge from the aeration tank is often mixed in at 20 to 40% of the total. Without polymer conditioning at 3 to 6 kg per tonne of dry solids, this mixture filters slowly and the cake stays above 75% moisture.
How much sludge does a 500 to 5,000 m³/day plant generate?
A dyeing plant generates 0.4 to 0.8 kg of dry solids per m³ of effluent, so a 500 m³/day plant produces 200 to 400 kg/day, a 2,000 m³/day plant 0.8 to 1.6 t/day and a 5,000 m³/day plant 2 to 4 t/day of dry solids.
At 3% solids, 1 tonne of dry solids is 33 m³ of thickened sludge. At 65% cake moisture it becomes 2.9 t of cake, about 2.4 m³ at 1.2 t/m³. That 14-fold volume reduction is why plants switch from drying beds and belt presses to a filter press.
| Effluent flow (m³/day) | Dry solids (kg/day) | Thickened sludge at 3% (m³/day) | Cake at 65% moisture (m³/day) |
|---|---|---|---|
| 500 | 200–400 | 7–13 | 0.5–1.0 |
| 1,000 | 400–800 | 13–27 | 1.0–1.9 |
| 2,000 | 800–1,600 | 27–53 | 1.9–3.8 |
| 5,000 | 2,000–4,000 | 67–133 | 4.8–9.5 |
Should I size the press by hydraulic flow or by plate volume?
Size the press by cake volume per cycle first, then check the hydraulic side: the feed pump must fill the press within 20 to 40 minutes, which for a 2,000 m³/day plant means a 30 to 50 m³/h pump at 0.6 to 0.8 MPa.
Plate sizing works from the cake side. Divide the daily cake volume by the cycles per day, usually 2 to 3 on chemical sludge, to get the chamber volume per cycle. Divide by the chamber volume of one plate to get the plate count, and add a 20 to 30% safety factor for peak dye runs.
| Effluent flow (m³/day) | Plate size (mm) | Chamber volume per plate (m³) | Plates | Cycles per day | Filter area (m²) |
|---|---|---|---|---|---|
| 500 | 800 | 0.013 | 40–60 | 1–2 | 40–60 |
| 1,000 | 1000 | 0.023 | 50–80 | 1–2 | 80–130 |
| 2,000 | 1250 | 0.040 | 60–100 | 2 | 160–260 |
| 5,000 | 1500 | 0.060 | 100–150, or 2 units | 2–3 | 380–570 |
Hydraulic sizing then confirms the pump. A 2,000 m³/day plant sends 27 to 53 m³ of sludge per day to the press; two cycles filled in 30 minutes need a 30 to 50 m³/h pump. An air-operated diaphragm pump is common below 30 m³/h and a progressing cavity pump above that. The full method is in our guide on how to calculate filter press capacity.
What cake moisture can a filter press reach on dyeing sludge?
A chamber filter press reaches 60 to 70% cake moisture on coagulated dyeing sludge at 0.6 to 0.8 MPa feed pressure; a membrane filter press with 1.5 to 2.0 MPa squeeze reaches 50 to 55%, which cuts cake mass by a further 25 to 35%.
Ferric chloride sludge dewaters best, typically 60 to 65% on a chamber press; gelatinous alum and PAC sludge lands at 65 to 70%. Lime at 10 to 20% of dry solids improves both by 3 to 5 points but adds cake mass.
Cake moisture drives disposal cost, because textile sludge is classed as hazardous in India and several Vietnamese provinces and charged per tonne. Cutting moisture from 70% to 55% removes one third of the cake mass, which is why membrane presses are common at larger mills; see the membrane filter press page and our table of typical filter cake moisture by industry.
Why does dye residue blind the filter cloth, and which cloth prevents it?
Dye molecules, PVA sizing and fine hydroxide flocs lodge in the yarn of multifilament cloth and cut filtrate flow by 30 to 50% within 20 to 40 cycles; a monofilament polypropylene cloth of 400 to 600 g/m² with a 15 to 25 µm nominal opening resists this and is the standard choice for dyeing sludge.
Blinding shows up as longer fill times and wetter cake on the cloth side; reactive and disperse dyes are the worst. Monofilament yarn has a smooth surface that dye does not penetrate, so a wash at 0.8 to 1.0 MPa every 10 to 20 cycles restores flow.
When water washing is no longer enough, soak alum and ferric cloth in 3 to 5% hydrochloric or citric acid for 4 to 8 hours, and dye-blinded cloth in 2 to 3% sodium hydroxide at 40 to 50 °C. Expect a cloth life of 4 to 8 months on dyeing sludge; the cloth range and weights are listed under filter press cloth, and replacement timing is covered in how often filter press cloth should be replaced.
What is different for mills in Vietnam, Bangladesh, India and Indonesia?
Mills in these four countries face the same sludge but different rules: India’s Tirupur and Ludhiana clusters run zero liquid discharge, Bangladesh enforces ETP operation through its Department of Environment, Vietnam applies QCVN 13-MT:2015/BTNMT to textile effluent, and Indonesian industrial parks require dewatered sludge before licensed disposal.
India: zero liquid discharge plants produce 1.5 to 2 times the coagulation sludge because of reverse osmosis reject and evaporator salts. Presses there are sized for 3 cycles per day and usually use membrane plates.
Bangladesh: mills around Dhaka and Narayanganj run ETPs of 1,000 to 3,000 m³/day and ask for 1000 to 1250 mm chamber presses with manual or semi-automatic plate shifting.
Vietnam: dyeing mills in Binh Duong, Dong Nai and Nam Dinh industrial parks typically install compact 800 to 1000 mm presses with 40 to 60 plates.
Indonesia: mills in Bandung, Semarang and Solo often combine chemical and biological sludge, so cationic polymer plus lime conditioning is common.
Brand owners increasingly require the ZDHC Wastewater Guidelines, which also cover documented sludge handling; the text is published by the ZDHC Roadmap to Zero programme.
Why buy a textile sludge filter press from Senjie?
Senjie is a China-based manufacturer of chamber, membrane, plate-and-frame and fully automatic filter presses, founded in 2014, with equipment supplied to buyers in 40+ countries across Southeast Asia, India, Africa, the Middle East and Latin America. For dyeing sludge, Senjie supplies presses from 630 to 1500 mm, polypropylene plates rated to 90 °C, monofilament PP cloth cut to the plate, and matched diaphragm or progressing cavity feed pumps. Each press is sized from effluent flow, coagulant type and sludge test data, and test-run before shipping. Typical lead time is 25 to 45 days.
Frequently Asked Questions
How many filter press plates does a 1,000 m³/day dyeing plant need?
About 50 to 80 plates of 1000 mm size running 1 to 2 cycles per day. This handles 400 to 800 kg of dry solids per day, or 13 to 27 m³ of thickened sludge at 3% solids, with a 20 to 30% margin for peak dye runs.
What cake moisture can I expect from alum or PAC dyeing sludge?
65 to 70% moisture on a chamber filter press at 0.6 to 0.8 MPa. A membrane press with 1.5 to 2.0 MPa squeeze brings this to 52 to 55%. Ferric chloride sludge is 3 to 5 percentage points drier in both cases.
Which filter cloth resists dye blinding?
Monofilament polypropylene cloth of 400 to 600 g/m² with a 15 to 25 µm nominal opening. Dye does not penetrate the smooth single-strand yarn, so a 0.8 to 1.0 MPa water wash every 10 to 20 cycles restores flow. Expect 4 to 8 months of service life.
Do I need polymer to dewater textile chemical sludge?
Yes in almost every case. Dose 2 to 4 kg of cationic polymer per tonne of dry solids for ferric sludge and 3 to 6 kg/t for alum or PAC sludge. Without polymer the fill time doubles and cake moisture stays above 75%.
Is a membrane filter press worth it for a textile mill?
Usually above 1,500 m³/day or wherever cake is disposed of as hazardous waste. Dropping moisture from 68% to 54% cuts cake mass by 30%, which at 1.5 t of dry solids per day saves 1.4 t of cake per day and repays the higher press cost in 1 to 3 years.
Send your effluent flow, coagulant type and sludge solids to the Senjie team for a plate count and quotation via the contact page.