Scouring and bleaching are among the thirstiest steps in textiles. Mills are now cutting water use by 50–80% with low‑liquor‑ratio equipment, rigorous rinse reuse, and closed‑loop treatment trains that hit 95–98% recycling.
The numbers are daunting. The global textile industry used about 79×10^9 m^3 of water in 2015 — and consumption is projected to climb another 63% by 2030 (www.mdpi.com). Wet processing — the pretreatment and finish steps like scouring, bleaching, dyeing, and finishing — accounts for roughly 72% of that total (www.mdpi.com).
On the factory floor, producing and dyeing 1 kg of cotton fabric can take on the order of 100–300 L of water (journals.plos.org) (link.springer.com). A Bangladesh survey of dyehouses averaged ~164 L/kg of fabric (with 119 L/kg discharged as wastewater) (journals.plos.org), and U.S. EPA data pegs ≈40 L of clean water per kg even for simple coloring (link.springer.com) — implying multiple hundreds of liters per kg across pre‑treatments. Dyeing/bleaching/finishing together typically consume more than 50% of a mill’s total water (link.springer.com).
Low‑liquor‑ratio equipment adoption
One lever moves a lot: low‑liquor‑ratio (LLR) processing, where the bath “liquor ratio” is the water:fabric ratio. Modern jet and winch machines routinely run at 1:5–1:3 instead of the old 1:10–1:20 (www.sarkengg.in). Upgrading to LLR machines alone can cut process water by roughly 50–80% (www.sarkengg.in), while many plants in developing regions still run at ratios >1:10 with minimal reuse (www.sarkengg.in).
On continuous bleaching lines, advanced open‑width washers with counter‑current spray plus high‑speed extraction cut fresh intake and yield a more concentrated effluent that’s easier to treat; some units integrate spray/vacuum/ultrasonic washers that recirculate rinse water in closed loops (link.springer.com). Textile parks in places like Turkey report near‑100% process‑water reuse when LLR machines are combined with rigorous counter‑current rinsing (www.sarkengg.in).
In practice, swapping legacy high‑liquor gear for ≤1:5 LLR often halves or better the water used in scouring/bleaching; moving to ~1:4 has been cited for 50–80% savings (www.sarkengg.in). Microprocessor controls and efficient extraction reduce both water and steam demand, and continuous multistage washers (“Winch” or overflow circulator systems) usually run at ≤1:6 in advanced mills — lower in best practices (www.sarkengg.in). The bottom line: LLR is an impactful, low‑risk first step (www.sarkengg.in).
Rinse reuse and counter‑current washing
LLR still requires some fresh water to hold bath chemistry steady. But the “spent” liquor from scouring and bleaching carries untapped cleaning power — typical hydrogen peroxide (H₂O₂) consumption is only ~15–25% per batch (textclothsustain.springeropen.com). Multiple studies show pretreatment liquor can be reused by replenishing chemicals: Harane and Adivarekar (2017) recycled cotton scouring and bleaching baths 3–4 times by adding measured NaOH and H₂O₂ (medcraveonline.com). After four cycles, fabric wettability, whiteness and dyeability were comparable to fresh‑water runs (medcraveonline.com) (textclothsustain.springeropen.com).
In those trials, scouring water recycled thrice gave the same whiteness (Tegewa rating, a whiteness index) and absorbency as fresh‑water scouring; recycled bleaching baths maintained acceptable whiteness with only a slight Tegewa drop after three cycles (textclothsustain.springeropen.com). The trade‑off is extra dosing: after three reuses, peroxide consumption rose to ~32% (from ~15% initially) and alkali to 60% (from 30%), which tops up the liquor while shrinking effluent volume per cycle (textclothsustain.springeropen.com).
Counter‑current rinsing (moving the cleanest rinse water to the previous stage so each liter does multiple passes) typically reuses rinse water 3–4 times before discharge (www.sarkengg.in). Industry practice often chains 3–5 tanks, concentrating effluent for easier treatment. Many full‑scale mills have deployed this: the Battelle Textile Wastewater (U.S. EPA) report cites numerous scouring lines reusing rinses counter‑currently (nepis.epa.gov).
Marrying cascaded rinses with treatment extends reuse: rinse water that passes through ultrafiltration (UF) and then membrane systems such as RO (reverse osmosis) can be fed back as make‑up to the first rinse (www.sarkengg.in). European high‑tech mills report >90–100% rinse‑water reuse using such cascade + membrane schemes (www.sarkengg.in). In Bangladesh, a pilot across 18 factories found rinse‑water reclaim is gaining traction as groundwater buffers shrink (journals.plos.org). Even household garment washes have been treated with microfiltration/UF for reuse (pmc.ncbi.nlm.nih.gov), and Italy’s Prato textile district recycles large volumes via extensive treatment networks (www.mdpi.com).
Quantitatively, repeated rinse and bath reuse delivers ~40–75% water savings in lab and pilot trials. In Harane’s work, using the same bath four times effectively meant only ~25% of the initial fresh water was needed per kg, with the rest recirculated. The LIFE ANHIDRA demonstrator in Portugal reports 98% wash‑water reuse in finishing machines, cutting effluent by 92% (environment.ec.europa.eu). In 60 days of trial operation, ANHIDRA reused ~21,000 m^3 of water — about 123,400 m^3/year at that rate (environment.ec.europa.eu).
Closed‑loop treatment trains (MBR→UF→RO)
Closed‑loop systems push toward near‑total recycling by treating a plant’s own effluent and returning it to the line. Practically, that means coupling counter‑current rinses with filtration and oxidation steps to purify water; the EU‑funded Waste2Fresh and ANHIDRA projects target near‑zero discharge by integrating catalytic degradation with UF, driving fresh‑water intake effectively to zero (sustainablebrands.com) (environment.ec.europa.eu).
In a closed‑loop wash plant, all wastewater is pre‑screened in primary steps (screens and primary separation) — a role served by wastewater physical separation — then routed through a treatment train (e.g., membrane bioreactors, MBR, to degrade organics; followed by UF and RO) and returned to the first rinse. Advanced plants report >95% of wash water recycled, with many Chinese mills operating under Zero Liquid Discharge (ZLD) mandates that recover ≥95% of process water and evaporate/crystallize the rest (www.sarkengg.in). European mills are piloting full‑loop cycles; ANHIDRA reuses 98% in Portugal (environment.ec.europa.eu). Similar systems are being tested for scouring/bleaching.
Coupled with LLR, these loops can approach “water‑neutral” operation — essentially keeping water inside the plant. The payoffs are tangible: reduced fresh‑water purchases, near‑elimination of effluent discharge fees, and easier compliance as regulations tighten. As one EU source notes, such systems can save millions of cubic meters of water over a few years (environment.ec.europa.eu).
Measured outcomes and loads
Combined strategies deliver outsized gains. Installing LLR machines around 1:4 and running counter‑current rinses can reduce scouring/bleaching water use by about 50–80% (www.sarkengg.in). Reusing rinse water 3–4× and recycling via UF/RO routinely cuts net demand to similar degrees. One industrial case cut finishing‑laundry discharge by 92% thanks to 98% water reuse (environment.ec.europa.eu). Industry guides note hybrid UF/RO + evaporation ZLD designs can recover more than 95% of textile wastewater (www.sarkengg.in).
The chemistry improves too. Reusing bleach baths in Harane’s trial lifted effective peroxide use from ~15% to ~32% — a 60% utilization of what would otherwise be discharged — so only about 65% of peroxide needed ended up as new effluent (textclothsustain.springeropen.com). Counter‑current lines concentrate residual alkali and lint in the final tank, easing downstream treatment — often a 10× concentration of effluent, per [11].
Adoption, cost, and energy
Adoption is rising. European consultants note machinery parks in Europe and Turkey are now commonly equipped for closed‑loop reuse (www.sarkengg.in). In South Asia, government and IFC initiatives have pushed specific water use from 300 L/kg a few years ago down toward 100–150 L/kg through Cleaner Production standards.
The arithmetic is compelling: saving 100 L per kg on a 10 t/day mill avoids ~1,000 m^3/day of extraction ⇒ ~365,000 m^3/yr. In the ANHIDRA example, a single plant saved ~123,000 m^3/yr (environment.ec.europa.eu) just from finishing recirculation, translating to millions of dollars and environmental impact saved.
Energy penalties from pumps, membranes, and evaporation exist but are often offset by less water and fewer chemicals. Closed loops commonly recover heat or condensate, and efficient extraction (e.g., vacuum units on washers) can cut steam demand (link.springer.com). From a business view, lower water and discharge fees plus compliance benefits tend to justify the capex; the LIFE ANHIDRA and Waste2Fresh projects are publicly supported because they promise savings beyond traditional methods (environment.ec.europa.eu) (sustainablebrands.com).
Source notes and URLs
Catarino, M.L., Sampaio, F., Gonçalves, A.L. (2025). Sustainable Wet Processing Technologies for the Textile Industry: A Comprehensive Review. Sustainability 17(7):3041. DOI:10.3390/su17073041 (www.mdpi.com).
Thombre, N., Patil, P., Yadav, A., Patwardhan, A. (2025). A Short Review on Water Management and Reuse in Textile Industry – A Sustainable Approach. Discover Water, 5:26 (2025) (link.springer.com) (link.springer.com).
Uddin, M.A., Begum, M.S., Ashraf, M., Azad, A.K., Adhikary, A.C., Hossain, M.S. (2023). Water and chemical consumption in the textile processing industry of Bangladesh. PLOS Sustainable Transformation 2(7):e0000072 (journals.plos.org).
European Commission, Directorate‑General for Environment (2024, Aug 29). Saving water through a closed‑loop system for garment finishing. (environment.ec.europa.eu) (environment.ec.europa.eu).
SARK Engineers & Consultants (2023). Innovative Water‑Saving Technologies in Technical Textile Wet Processing. (www.sarkengg.in) (www.sarkengg.in).
Harane, R.S., Adivarekar, R.V. (2017). Sustainable Processes for Pre‑treatment of Cotton Fabric. Textiles and Clothing Sustainability 2:2 (2017) (textclothsustain.springeropen.com) (textclothsustain.springeropen.com) (see also Harane et al. experiments on scouring/bleaching bath reuse). Additional experimental detail on bath recycle: (medcraveonline.com).
EPA/Battelle counter‑current rinse reuse cases: (nepis.epa.gov). Household laundry UF reuse: (pmc.ncbi.nlm.nih.gov). Prato textile district membrane recycling: (www.mdpi.com). Waste2Fresh closed‑loop overview: (sustainablebrands.com).
