Techno-Economic Analysis of Dye Separation in Textile Recycling
(2024) In TVVR 5000 VVRM05 20232Division of Water Resources Engineering
- Abstract (Swedish)
- This study determines the technical and economic feasibility of separating dye from a process filtrate in industrial textile recycling using electrocoagulation or sequences of membrane filtration with microfiltration, ultrafiltration, nanofiltration and reverse osmosis. The lower requirements for treating this stream, compared to previously researched dyehouse effluents, left treatments not good enough for dyehouses viable for this process filtrate. Electrocoagulation effectively removes the dye from the filtrate but limited downstream research, coagulant pollution and excessive pH control left the process filtrate unfit for recirculation to the process. Therefore, the design of this treatment method was focused on the core process and... (More)
- This study determines the technical and economic feasibility of separating dye from a process filtrate in industrial textile recycling using electrocoagulation or sequences of membrane filtration with microfiltration, ultrafiltration, nanofiltration and reverse osmosis. The lower requirements for treating this stream, compared to previously researched dyehouse effluents, left treatments not good enough for dyehouses viable for this process filtrate. Electrocoagulation effectively removes the dye from the filtrate but limited downstream research, coagulant pollution and excessive pH control left the process filtrate unfit for recirculation to the process. Therefore, the design of this treatment method was focused on the core process and should only be applied on waste streams leaving the process. The direct operational cost of electrocoagulation was estimated to 1.22 $/m3. For membrane filtration, a complete process was designed from incoming filtrate to handling of end products. An indirect series of first external and then submerged hollowfiber- ultrafiltration shows best performance. This both concentrates pollutants and reclaims the process filtrate. A CAPEX estimation of $680 000 and OPEX of $360 000 gives a total treatment cost of 0.49 $/m3 for operations in Sundsvall, Sweden. Both electrocoagulation and membrane filtration efficiently remove dye from the filtrate and can be industrially feasible. (Less)
- Popular Abstract
- Cost efficient membrane filtration can make textile recycling more sustainable by separating the dyes from the solvents.
To make the textile industry sustainable it must become circular by recycling textiles. Currently textile recycling use, discard and emit water, chemicals, water-based solvents, and dye when these could instead be used cyclically. For example, the solvents used to remove the dye from clothes does not get consumed, only saturated of dye. If the dye can be separated from the solvent, then the solvent can be reused for the same purpose while also avoiding harmful release of dye through collection after the separation. A proposed design of a membrane filtration system achieves this at an estimated unit cost of $0.49 per m3... (More) - Cost efficient membrane filtration can make textile recycling more sustainable by separating the dyes from the solvents.
To make the textile industry sustainable it must become circular by recycling textiles. Currently textile recycling use, discard and emit water, chemicals, water-based solvents, and dye when these could instead be used cyclically. For example, the solvents used to remove the dye from clothes does not get consumed, only saturated of dye. If the dye can be separated from the solvent, then the solvent can be reused for the same purpose while also avoiding harmful release of dye through collection after the separation. A proposed design of a membrane filtration system achieves this at an estimated unit cost of $0.49 per m3 for constructing and operating a plant in Sweden. This system uses advanced industrially available hollow-fiber ultrafiltration(HF-UF) membranes to treat large quantities of wastewater with high precision.
Another explored treatment method is electrocoagulation that coagulates pollutants with electrolysis and leaves a purified solution behind. While electrocoagulation is shown to be efficient at the main objective, the dye removal, it turned out that the solvent cannot be reused, partially falling short of the aim. The direct operational unit cost of electrocoagulation was estimated to $1.22 per m3.
Current research is focused on separating dye and reclaiming solvents in dyehouses producing new clothing. Reusing the solvent for coloring have higher purity requirements than for decoloring in textile recycling. For this reason, in textile recycling specifically it is smarter to use an indirect membrane sequence to reclaim more solvent but with lower purity compared to dyehouses which must use direct series to meet strict purity limits. Dyes used for textiles are often toxic chemical compounds not easily broken down in nature or at treatment plants. The dye therefore needs to be separated to not exceed the capacity of the chemical loading of treatment plants. This thesis concludes that HF-UF is the best available option all in all and should be the long-term solution for industrial separation of dye in textile recycling. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9148354
- author
- Lundberg, David LU
- supervisor
- organization
- course
- VVRM05 20232
- year
- 2024
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Dye, Membrane filtration, Electrocoagulation, Techno-economic analysis, Pre-feasibility study
- publication/series
- TVVR 5000
- report number
- TVVR23/5010
- ISSN
- 1101-9824
- language
- English
- additional info
- Examiner: Magnus Larson
- id
- 9148354
- date added to LUP
- 2024-02-12 14:34:46
- date last changed
- 2024-02-12 14:34:46
@misc{9148354,
abstract = {{This study determines the technical and economic feasibility of separating dye from a process filtrate in industrial textile recycling using electrocoagulation or sequences of membrane filtration with microfiltration, ultrafiltration, nanofiltration and reverse osmosis. The lower requirements for treating this stream, compared to previously researched dyehouse effluents, left treatments not good enough for dyehouses viable for this process filtrate. Electrocoagulation effectively removes the dye from the filtrate but limited downstream research, coagulant pollution and excessive pH control left the process filtrate unfit for recirculation to the process. Therefore, the design of this treatment method was focused on the core process and should only be applied on waste streams leaving the process. The direct operational cost of electrocoagulation was estimated to 1.22 $/m3. For membrane filtration, a complete process was designed from incoming filtrate to handling of end products. An indirect series of first external and then submerged hollowfiber- ultrafiltration shows best performance. This both concentrates pollutants and reclaims the process filtrate. A CAPEX estimation of $680 000 and OPEX of $360 000 gives a total treatment cost of 0.49 $/m3 for operations in Sundsvall, Sweden. Both electrocoagulation and membrane filtration efficiently remove dye from the filtrate and can be industrially feasible.}},
author = {{Lundberg, David}},
issn = {{1101-9824}},
language = {{eng}},
note = {{Student Paper}},
series = {{TVVR 5000}},
title = {{Techno-Economic Analysis of Dye Separation in Textile Recycling}},
year = {{2024}},
}