Spinning Future Threads

All of the world’s population wears clothing. Yet, the most commonly used fibres for fashion are far from sustainable. Here, we present the highlights from research into the potential of using agricultural residues as a textile fibre feedstock.

The research

More than 60% of fibres in fashion are oil-based and place a burden on natural resources due to unchecked, unsustainable production. Similarly, natural fibres such as conventional cotton – the second most widely used textile fibre – rely on intensive agrochemical and water use.

The current textile production process has disastrous effects on the environment. Global fibre production has reached well over 100 million tonne per year in 2019 and is expected to rise even further. Developing alternative fibre sources is more critical now than it’s ever been. 

The research concentrates on South Asia and Southeast Asia, because these regions are already critical natural fibre producers and textile hubs. Asia also accounts for almost 40% of the cropland worldwide, leading to massive amounts of potentially usable residue from agricultural activities. Currently, these waste streams are often disposed of through mass burning, causing heavy air pollution.



In an effort to turn these challenges into an opportunity, the research team explored the following question:

How can residue streams from food production in South and Southeast Asia be put to use as a sustainable fibre source for textile production?

Bangladesh

Thailand

Cambodia

Vietnam

Indonesia

Sri Lanka

India

Pakistan

Requirements

A sustainable fibre source from agricultural residues should

  • Use existing un- or underused bio-mass resources
  • Reduce waste
  • Generate additional revenue streams to farmers
  • Show potential for large scale use

A sustainable fibre source from agricultural residues shouldn't

  • Increase land use
  • Increase mono culture
  • Compete with food production or water use
  • Affect current socio-economic ecosystems negatively

Process

Process

Synthetic fibres are originally made from fossil fuels, and examples include polyester (PET) and the polyamide nylon. Due to their non-renewable origins, the major challenge for synthetic fibres is to transition to viable renewable sources. The key to addressing this is glucose, which is the feedstock for making synthetic fibres which are then converted into a filament. 

Previous studies have shown that it is technically possible to produce all major monomers from biomass (Harmen et al. 2013). Monomers with acid and alcohol functionalities, such as lactic acid and succinic acid, can be produced well from biomass like sugars (i.e., glucose), since the oxygen atoms needed for these building blocks are already present in the biomass.

These findings pave the way for producing synthetic fibres from bio-based renewable sources, since the production route for bio-based polymers usually starts with a glucose molecule. The glucose molecule is converted by chemical means or fermentation to the target molecule. Accordingly, no specific type of biomass is required to produce synthetic bio-based fibres; the only requirement is that the selected biomass should contain glucose in the form of sucrose, starch or cellulose. For this reason, biosynthetics from agro-residues as a potential pathway was not considered as a part of the scope of this study.


To make fibres for textile from agro-residue, two main processing routes were researched: cellulose extraction and fibre extraction. The criteria for each route are:


Agro-residue
In this study, agricultural waste and residues (or agro-residues) will primarily refer to harvest residues, also known as crop residues. Crop residues comprise both field residues and process residues. The first refers to the residues left in the agricultural field or orchard after the crop is harvested; some examples are stalks, stubble (stems), leaves and seed pods. The latter refers to the residues left after the crop is processed into a usable resource; common examples are sugarcane bagasse and molasses (Agamuthu 2009; Hoornweg and Tata 2012; Obi, Ugwuishiwu and Nwakaire 2019; UN 1997).



Processing routes
Textile fibres from cellulosic sources can be produced using a number of processing techniques, depending on the properties and characteristics of the fibre source. For agricultural fibre sources, the processing techniques focus on maintaining the natural fibre’s cellulosic structure, either as single filaments or fibre bundles. For others like MMCFs and bio-based synthetic fibres, the processing focuses on extraction of cellulose and glucose, respectively, from the fibre source, then following a series of steps to produce the filaments that are processed into different fabrics.


Cellulose extraction

  • At least 30% cellulose content
  • Availability of at least one million MT/year/country
  • Reasonable expectation of large unused residue sources

For cellulose extraction, a reasonable expectation of large unused residue sources implies that the residual biomass has limited competing uses. A large unused potential is particularly evident when the selected crop residues are being burnt on the field.

Fibre extraction

  • Degree of polymerization, or DP, should be over 2500
  • Should belong to a fibre plant family
  • Should be identified in literature as suitable for fibre extraction


Polymerization
The Degree of polymerization (DP) is defined as number of repeating monomer units in the polymers. The Degree of a polymerization is calculated by taking ratio of molecular weight of the polymer and molecular weight of the repeat unit.


For fibre extraction, the minimum availability of residues was set much lower, because the sizes of fibre extraction plants can be much smaller than for cellulose dissolving factories.

Highlights

1

Large quantities are indeed available

Large quantities of agricultural residues are indeed available in the eight countries that were researched. Based on residue volume production per year, high cellulose or fibre content and suitability for use in textiles, the top potential sources for cellulose and fibre extraction per country are the following:

cellulose

fibre

Bangladesh

rice straw

banana pseudo-stem

Cambodia

rice straw

India

rice straw

sugarcane trash

wheat straw

bagasse

maize straw

banana pseudo-stem

sorghum straw

pineapplle leaves

Indonesia

rice straw

bagasse

maize straw

banana pseudo-stem

oil palm EFB

sugarcane trash

Pakistan

rice straw

wheat straw

bagasse

maize straw

sugarcane trash

Sri Lanka

rice straw

Thailand

rice straw

bagasse

maize straw

oil palm EFB

banana pseudo-stem

sugarcane trash

pineapple leaves

Vietnam

rice straw

maize straw

banana pseudo-stem

pineapple leaves

2

Residue streams with high potential

Overall, the findings indicate that rice straw offer the largest potential across all eight countries, followed by Empty Fruit Bunches (EFBs) from oil palm. Both sources also offer the best cost economics.

Wheat straw, sugar cane bagasse, banana pseudo-stem, maize and sorghum also offer potential. However, to extract cellulose from these residue streams first some technical challenges must be overcome.


Empty Fruit Bunches (EFBs)
EFB’s offer high cellulose yields and currently have limited alternative uses. However, the authors recommend treating this commodity with caution, as its use could lead to an expansion in oil palm cultivation – a sector already challenged by significant sustainability issues.


Residue availability

Cellulose content

Suitability to produce textiles

Non-competing uses

Pre-processing infrastructure

Cost economics

Technological suitability

Scalability

Performance

rice

maize

pineapple

banana

sugarcane

okra

oil palm

wheat

3

Hub potential

A spatial mapping analysis identified at least 10 specific locations where large-scale availability of agricultural residue streams coincides with existing or potential processing capacity. This indicates that hubs for converting agro-residues into textile fibre could be established within a sourcing radius of 100 kms, and in some cases, of just 50 kms.

h3_graphic_map

Thailand

Thailand is the only country in which the pineapple production is sufficiently large and concentrated to justify a mill for fibre extraction from pineapple leaves. In Thailand, also a small cellulose dissolving mill (max. 75 kton cellulose per year) can run on sugarcane trash and bagasse from a sourcing distance within 100 km.

3

hubs cellulose

2

hubs fibre

Cambodia

Rice straw is abundantly available in Cambodia. Most notably in the south, where a hub location would also be close to the rice producing regions of Thái Bình and An Giang in Vietnam.

2

hubs cellulose

0

hubs fibre

Vietnam

Apart from rice, in Vietnam also banana pseudo-stems are a promising biomass source for the production of textile fibres. Most notably in the south, where a fibre extraction plant could source enough biomass in the vicinity. 

2

hubs 
cellulose

1

hub 
fibre

Indonesia

The combination of rice and maize cultivation produces enough straw and stover to source biomass for cellulose dissolving mills of varying size. In Indonesia the empty fruit bunches from palm oil are also a biomass source with enough volume that isn’t used for other purposes at present.

4

hubs cellulose

1

hub
fibre

India

From the eight investigated countries, India is the largest. Due to the diverse climate, it has the largest and most diverse crop production resulting in a high number of possible hub locations. By combining rice and wheat straw large sourcing sizes can be met. Also, enough sugarcane residue (trash and bagasse) is potentially available to supply a number of large cellulose dissolving plants within a 50-km sourcing range. 

4

hubs cellulose

1

hub 
fibre

Bangladesh

Bangladesh has a very high concentration of rice fields and banana plantations, making it a suitable location for both large cellulose dissolving plants and fibre extraction mills. Enough rice straw is available to produce 500 kilotons of cellulose per year within a 100 km sourcing radius at two different locations. 

2

hubs cellulose

1

hub 
fibre

Pakistan

The volume and density of sugarcane and wheat production isn’t sufficiently large to produce enough biomass for large cellulose dissolving plants in Pakistan. However, small or medium sized production plants should be possible based on the analysis of available waste streams. 

2

hubs cellulose

0

hubs fibre

Sri Lanka

The smallest country in the study still produces enough rice straw to justify a small cellulose dissolving plant. 

1

hub 
cellulose

0

hubs fibre

4

The Business case

It’s always difficult to predict costs and benefits of a system that isn’t established yet. But, since a favourable financial picture is instrumental for change to take off, the research looked into possible business models. 

The cost projections vary, but are in general encouraging. The lowest cellulose-based biomass extraction-plant gate cost is projected at USD 63 per tonne of cellulose, with the upper end of the range at USD 160 per tonne. 

Fibre extraction plants do not require very large facilities to reach optimal economies of scale. For cellulose extraction plants, scale is much more important to take into account.

The major factors to take into account when assessing the costs for using agro-residue as a feedstock for textile fibres are the following:

Compensation cost for the loss of nutrients from the field due to residue removal

Purchase cost of the biomass

Densification cost, for example when the agro-residue is bulky or contains a lot of moisture

Transportation cost, which can be local, short or long distance

Storage cost, to even out seasonal availability of biomass sources and keep mills operational year-round

On- and off-loading costs

Manufacturers can boost local economic development through long-term contracts, capacity building programs and incentive programs

Conclusion

Using agricultural waste streams has potential to

decrease extensive crop burning and its associated negative effects.

generate new, additional  revenue streams for low-income agricultural communities in South and Southeast Asia.

activate a more environmentally sustainable source of fibre for the booming fashion industry.

Next steps

A responsible and environmentally conscious approach is essential when utilizing agro-residues to build alternative textile value chains. The decision to commercialize new approaches should be governed by three principles.

How can responsible investment help to build long-term sustainable value chains from agricultural waste?

1

Maintaining ecological balance in the regions where they will be implemented.

2

Ensuring that they will enhance local livelihoods.

3

Respect the planetary boundaries that govern all natural resources.

Through this research, we hope to inspire manufacturers, innovators, design experts and global brands to take concrete steps towards a more sustainable fashion industry.

CALL TO ACTION

Let's demon­strate innovation

Most textile innovations are currently based on specific agro-residues available under very specific conditions. Their proven economic feasibility, can be the starting point to explore the potential of other agro-residues for cellulose extraction. 

At present, fibres extracted from agro-residues do not completely meet the requirements to make them an attractive replacement for conventional fibre sources. Blending fibres is necessary to address this challenge. 

Future innovation should focus on identifying favourable agro-residue based blends that offer softness, durability and elasticity. 

Let's refine science

Soil quality is a critical component of sustainable agricultural production. Where possible, nutrients shouldn’t leave the field. Also, returning the unused biomass to the fields after the usable cellulose is extracted should be accommodated. 

Using agro-residue streams as a source for textile fibres is only one possibility. Alternative uses such as nutrients, livestock feed or alternative energy, should be catalogued and mapped. Case by case the costs and benefits of different agro-residue uses to local ecosystems and agricultural practices should be evaluated. 

A decision support tool or scenario generator could help to assess different approaches for communities, government agencies, manufacturers, innovators and brands interested in agro-residue-based fibres. Such a tool should include standard estimates on labour and logistical costs, residue availability, impurity and yield estimates, etc. It would help to facilitate participation and secure community buy-in.


Let's build the system

Crop cultivation is inherently seasonal, whereas textile manufacturing is a year-round industrial process. To align both, it’s necessary to consider options like pre-processing, densification and safe storage to ensure consistent supplies that align with demand.

The quality of the fibres depends on the quality of the agro-residue. Both textile manufacturers and farmers benefit from long-term contracts that guarantee agro-residue production in accordance with a set of pre-defined quality parameters. Livelihood diversification, incentive programs, and local capacity building programs are ways in which manufacturers can boost local economic development around agro-residue sourcing hubs even more. 

Large investments are required to establish the new value chains proposed in this research. By supporting the science, building a narrative, and demonstrating innovation in a pre-competitive manner with the industry, we will be able to make the innovation market ready and catalyse the investments needed to scale it up. We strongly believe in building partnerships with local governments, textile manufacturers, fashion brands, farmer associations and logistic partners. The entire chain of stakeholders is needed to identify optimal strategies and unleash the potential of agro-residues for textile manufacturing.


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Spinning Future Threads

The Potential of Agricultural Residues as Textile Fibre Feedstock

June 2021

Colophon

Publishing date : June 2021

This reasearch was conducted by the Institute for Sustainable Communities, the World Resources Institute India and Wageningen University and Research. Laudes Foundation funded the research. All views expressed in the report are those of the research team and not necessarily those of Laudes Foundation. The boundaries and other information shown on any map in this work do not imply any judgement on the part of Laudes Foundation concerning the legal status of any territory or the endorsement or acceptance of such boundaries.

For any queries, please contact: materials@laudesfoundation.org.

This research was funded by the Laudes Foundation and conducted by the Institute for Sustainable Communities, Wageningen University and Research and the World Resources Institute India. All views expressed in the report are those of the research team and not necessarily those of the Laudes Foundation. 

World Resources Institute