Dataset and mathematical formulation for research paper "Reducing Water Impact in Textile Supply Chains: The Case of Hemp as a More Sustainable Textile Fiber"
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This document contains supplementary material for the manuscript entitled: Reducing Water Impact in Textile Supply Chains: The Case of Hemp as a More Sustainable Textile Fiber".
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SUPPLEMENTARY MATERIAL 1 Reducing Water Impact in Textile Supply Chains: The Case of Hemp as a More Sustainable Textile Fiber Section 1 contains complementary elements for the mathematical formulation of the optimization model proposed in the research paper, mainly the indices, sets, parameters, decision variables, and constraints. Section 2 is related to case study data collection and treatment. 1. Mathematical Formulation 1.1. Indices and related sets ๐, ๐ โ ๐ผ Locations of entities ๐ผ = ๐ผ๐ ๐ข๐ โช ๐ผ๐โช ๐ผ๐โช ๐ผ๐คโช ๐ผ๐โช ๐ผ๐๐๐ โช ๐ผ๐ ๐๐ โช ๐ผ๐๐๐๐ ๐ผ๐ ๐ข๐ Suppliers ๐ผ๐ Mills ๐ผ๐ Factories ๐ผ๐ค Warehouses ๐ผ๐ Clients ๐ผ๐๐๐ Airports ๐ผ๐ ๐๐ Seaports ๐ผ๐๐๐๐ Railway stations ๐, ๐ โ ๐ Products ๐ = ๐ ๐๐ โช ๐ ๐๐๐ โช ๐ ๐๐ ๐ ๐๐ Raw material ๐ ๐๐๐ Fabric ๐ ๐๐ Final product ๐ก โ ๐ Transport modes ๐ = ๐๐๐๐๐๐ โช ๐๐๐๐๐ก โช ๐๐ก๐๐๐๐ โช ๐๐ก๐๐ข๐๐ ๐๐๐๐๐๐ Plane ๐๐๐๐๐ก Boat ๐๐ก๐๐๐๐ Train
SUPPLEMENTARY MATERIAL 2 ๐๐ก๐๐ข๐๐ Truck ๐ โ ๐พ Time periods ๐พ = ๐พ๐๐๐๐ ๐ก โช ๐พ๐๐กโ๐๐ ๐พ๐๐๐๐ ๐ก First time period ๐พ๐๐กโ๐๐ All but first time period ๐ โ ๐ถ Environmental midpoint categories ๐ Allowed entity-entity connections ๐ = {(๐, ๐): ๐, ๐ โ ๐ผ} ๐๐ ๐ข๐๐ Connection between supplier and mill ๐๐๐ Connection between mill and factory ๐๐๐ Connection between factory and client ๐๐๐ค Connection between factory and warehouse ๐๐ค๐ Connection between warehouse and client As for airports, seaports, and railways, all connections are possible. For transportation restrictions purposes, the following were also computed: ๐๐๐๐๐ Connection between non-island countries ๐๐๐ ๐๐๐๐๐ Connection between island countries ๐๐๐๐๐_๐๐ ๐๐๐๐๐ Connection between non-island and island countries ๐๐๐ ๐๐๐๐๐ _๐๐๐๐ Connection between island and non-island countries ๐ Allowed product-entity relations ๐ = {(๐, ๐):๐ โ ๐ ห ๐ ๐ ๐ผ} ๐ ๐ ๐ข๐๐๐ Relation between supplier and raw material ๐ ๐๐๐ Relation between mill and raw material ๐๐๐๐๐ Relation between mill and fabric ๐ ๐๐๐๐ Relation between factory and fabric ๐ ๐๐๐ Relation between factory and final product
SUPPLEMENTARY MATERIAL 3 ๐๐ค๐๐ Relation between warehouse and final product ๐๐๐๐ Relation between client and final product As for airports, seaports and railways, all relations are possible. ๐น Allowed flows of materials between entities ๐น = {(๐, ๐, ๐): (๐, ๐) โ ๐ ห (๐, ๐) ๐ ๐} For the description of this subset, please consider the following examples: ๐น๐๐๐๐ ๐ข๐๐๐ Flow out (OUT) of raw material (RM) that leaves suppliers (SUP) and enters entity ๐ ๐น๐ผ๐๐๐๐ Flow in (IN) of raw material (RM) that leaves an entity ๐ and enters the mills (M) ๐๐๐ก Allowed transport modes in connections between entities ๐๐๐ก = {(๐ก, ๐, ๐): ๐ก โ ๐ ห (๐, ๐) ๐ ๐} ๐๐๐ก๐๐๐๐๐ Connections between airports by plane ๐๐๐ก๐๐๐๐ก Connections between seaports by boat ๐๐๐ก๐ก๐๐๐๐ Connections between railway stations by train ๐๐๐ก๐ก๐๐ข๐๐ All remaining connections ๐๐๐ก๐ถ๐๐ Network with all allowed connections ๐๐๐ก๐ถ๐๐ = {(๐ก, ๐, ๐, ๐):(๐ก, ๐, ๐)โ ๐๐๐ก ห (๐, ๐, ๐)๐ ๐น} 1.2. Parameters Parameters are grouped by type, namely entity, product, transport and environment, costs, and others. Entity related parameters ๐ ๐๐๐๐๐ Maximum supply capacity for raw material ๐ by supplier ๐ (ton) ๐๐๐๐๐ Maximum production capacity in mill ๐ (ton) ๐๐๐๐๐ Maximum production capacity in factory ๐ (ton) ๐ค๐๐๐๐ Maximum inventory capacity in warehouse ๐ (ton) ๐๐๐๐ Inventory level of product ๐ in warehouse ๐ in time period 1 (ton)
SUPPLEMENTARY MATERIAL 4 ๐ค๐ Necessary number of workers in entity ๐ to produce/store one ton of product ๐๐ Price per unit sold in client ๐ (c.u.) ๐๐๐ Demand by client ๐ in time period ๐ (ton) ๐ค๐ ๐ Water stress level index for each entity ๐ ๐ค๐๐ Water consumption of fabric production (m3/ton) ๐ค๐๐๐ Water consumption of final product production (m3/ton) Product related parameters ๐ต๐๐๐๐ ๐๐๐ First stage production bill of materials that specifies the amount of raw material ๐ necessary to produce one ton of fabric ๐ ๐ต๐๐๐๐ ๐๐ Last stage production bill of materials that specifies the amount of fabric ๐ necessary to produce one ton of final product ๐ ๐ต๐๐๐๐ ๐ Bill of materials at mills ๐ต๐๐๐๐ ๐๐ค Bill of materials at factories and warehouses ๐ต๐๐๐๐ ๐ก Bill of materials at airports, seaports and railway stations ๐ค๐๐๐ Water footprint of each raw material ๐ in each location of supplier ๐ ๐๐๐ค Final productโs weight (ton) Transport and Environment related parameters ๐ค๐๐ก๐ก Water consumption of each transport mode ๐ก (per tkm) ๐ค๐ก Average number of jobs created per transport mode ๐ก in airports, seaports and railway station (per tkm) ๐๐๐๐ ๐๐ Environmental impact characterization factor of raw material ๐ processing, at midpoint category ๐ (per ton) ๐๐๐๐ ๐๐๐ Environmental impact characterization factor of fabric ๐ production, at midpoint category ๐ (per ton) ๐๐๐๐ ๐๐ Environmental impact characterization factor of final product ๐ production, at midpoint category ๐ (per ton) ๐๐๐ก๐ Environmental impact characterization factor of transport mode t, at midpoint category ๐ (per tkm)
SUPPLEMENTARY MATERIAL 5 ๐๐ Normalization factor for midpoint category ๐ Costs ๐๐๐๐๐ Cost of raw material ๐ supplied by supplier ๐ (c.u./ton) ๐๐๐ Production cost at mills (c.u./ton) ๐๐๐ Production cost at factories (c.u./ton) ๐๐ Inventory cost at warehouses (c.u./ton) โ๐๐ Hub cost of entity ๐ (c.u.) ๐ก๐๐๐ก Transport cost for each transport mode ๐ก from location ๐, per tkm (c.u.) ๐๐๐๐๐ Labor cost of entity ๐ (c.u.) ๐๐๐ Lease cost of entity ๐ (c.u.) Others ๐๐๐ ๐ก๐๐ Distance between entity ๐ and entity ๐ (km) ๐ต๐๐๐ Large number ๐๐๐๐๐๐ Small number ๐๐ฆ Time horizon (years) ๐ก๐ Tax rate ๐๐ Interest rate 1.3. Decision Variables Continuous and positive variables ๐๐๐๐๐ก๐ Amount of product ๐ transported by transport mode ๐ก from entity ๐ to entity ๐ in time period ๐ ๐๐๐๐ Amount of inventory of final product ๐ in warehouse ๐ in time period ๐ ๐๐๐๐ Amount of product ๐ produced in entity ๐ in time period ๐ Binary variable ๐ ๐ = 1 if entity ๐ is used (excludes suppliers), 0 otherwise
SUPPLEMENTARY MATERIAL 6 1.4. Constraints Material Balances Material balance at mills ๐๐๐๐ =โ๐ต๐๐๐๐ ๐โ
๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ ๐น๐๐๐๐๐๐๐ , ๐ โ ๐ ๐๐๐ ๐ โ ๐ผ๐ โง ๐ โ ๐พ (1) โ๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ ๐:(๐,๐,๐) โ ๐น๐ผ๐๐๐๐ = โ๐๐๐๐๐ โ ๐๐๐๐ โ
๐ต๐๐๐๐ ๐๐๐, ๐ โ ๐ผ๐ โง ๐ โ ๐ ๐๐ โง ๐ โ ๐พ (2) Material balance at factories ๐๐๐๐ =โ๐ต๐๐๐๐ ๐๐ค โ
๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ ๐น๐๐๐๐๐๐ , ๐ โ ๐ ๐๐ ๐ โ ๐ผ๐ โง ๐ โ ๐พ (3) โ๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ ๐:(๐,๐,๐) โ ๐น๐ผ๐๐๐๐๐ = โ๐๐๐๐๐ โ ๐๐๐ โ
๐ต๐๐๐๐ ๐๐, ๐ โ ๐ผ๐ โง ๐ โ ๐ ๐๐๐ โง ๐ โ ๐พ (4) Material balance at warehouses in time period 1 ๐๐๐๐ +โ๐ต๐๐๐๐ ๐๐ค โ
๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ ๐น๐ผ๐๐ค๐๐ = ๐๐๐๐ +โ๐ต๐๐๐๐ ๐๐ค โ
๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ ๐น๐๐๐๐ค๐๐ ,(5) ๐ โ ๐ผ๐โง ๐ โ ๐ ๐๐ โง ๐ โ ๐พ๐๐๐๐ ๐ก Material balance at warehouses in remaining time periods ๐๐๐(๐โ1)+โ๐ต๐๐๐๐ ๐๐ค โ
๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ ๐น๐ผ๐๐ค๐๐ = ๐๐๐๐ +โ๐ต๐๐๐๐ ๐๐ค โ
๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ ๐น๐๐๐๐ค๐๐ ,(6) ๐ โ ๐ผ๐โง ๐ โ ๐ ๐๐ โง ๐ โ ๐พ๐๐กโ๐๐ Cross-docking at airports, seaports, and railway stations โ๐ต๐๐๐๐ ๐กโ
๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ (๐น๐ผ๐๐๐๐๐๐ โช ๐น๐ผ๐๐๐๐๐๐๐โช ๐น๐ผ๐๐๐๐๐๐) = โ๐ต๐๐๐๐ ๐กโ
๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ (๐น๐๐๐๐๐๐๐๐ โช ๐น๐๐๐๐๐๐๐๐๐โช๐น๐๐๐๐๐๐๐๐) ,(7) (๐, ๐) โ (๐๐๐๐๐๐ โช ๐๐๐๐๐๐๐ โช ๐๐๐๐๐๐) โง ๐ โ ๐พ โ๐ต๐๐๐๐ ๐กโ
๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ (๐น๐ผ๐๐ ๐๐๐๐ โช ๐น๐ผ๐๐ ๐๐๐๐๐โช ๐น๐ผ๐๐ ๐๐๐๐) = โ๐ต๐๐๐๐ ๐กโ
๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ (๐น๐๐๐๐ ๐๐๐๐ โช ๐น๐๐๐๐ ๐๐๐๐๐โช๐น๐๐๐๐ ๐๐๐๐) ,(8) (๐, ๐) โ (๐ ๐ ๐๐๐๐ โช ๐๐ ๐๐๐๐๐ โช ๐๐ ๐๐๐๐) โง ๐ โ ๐พ โ๐ต๐๐๐๐ ๐กโ
๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ (๐น๐ผ๐๐๐๐๐๐๐ โช ๐น๐ผ๐๐๐๐๐๐๐๐โช ๐น๐ผ๐๐๐๐๐๐๐) = โ๐ต๐๐๐๐ ๐กโ
๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ (๐น๐๐๐๐๐๐๐๐๐ โช ๐น๐๐๐๐๐๐๐๐๐๐โช๐น๐๐๐๐๐๐๐๐๐) ,(9) (๐, ๐) โ (๐๐๐๐๐๐๐ โช ๐๐๐๐๐๐๐๐ โช ๐๐๐๐๐๐๐) โง ๐ โ ๐พ Constraints (1) and (2) model the material balance at mills. Constraint (1) assures that the production of fabric at mills (first term), during all time periods, is equal to the outgoing flow of fabric (second term). Constraint (2) sets the necessary amount of raw material to be sent by the supplier, by matching the amount of ingoing flow of raw material (first term) with the level
SUPPLEMENTARY MATERIAL 7 of production of fabric (second term). These constraints ensure that there is no possibility of stock in mills, as all the flow of material that enters the mills is used for production in that same time period. Similarly, constraints (3) and (4) model the material balance at factories, ensuring there is no possibility for stock at the factories. Constraints (5) and (6) express the material balance at the warehouses. The first assures that, during the first time period, the initial stock of the final product and its inbound flow to the warehouse (first term) is equal to the amount kept in stock plus the outgoing flow of the final product (second term). Constraint (6) models the remaining time periods by replacing the initial stock of the final product ๐๐๐๐ with the remaining stock from the previous time period ๐๐๐(๐โ1). The airports, seaports, and railway stations operate in a cross-docking mode; therefore, no stock is made available at these sites. Constraints (7), (8), and (9) state that the inbound flow at an airport, seaport, and railway station, respectively, equal their outbound flow. Entity capacity constraints Entity existence constraints โ๐๐๐๐๐ก๐ (๐ก,๐,๐):(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ โค ๐ต๐๐๐ โ
๐ ๐, ๐ โ ๐ผ\๐ผ๐ ๐ข๐ โง ๐ โ ๐พ (10) โ๐๐๐๐๐ก๐ (๐ก,๐,๐):(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ โฅ ๐๐๐๐๐๐ โ
๐ ๐, ๐ โ ๐ผ\๐ผ๐ ๐ข๐ โง ๐ โ ๐พ (11) Supply capacity โ๐๐๐๐๐ก๐ (๐ก,๐):(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ ๐:(๐,๐,๐) โ ๐น๐๐๐๐ ๐ข๐๐๐ โค ๐ ๐๐๐๐๐, ๐ โ ๐ผ๐ ๐ข๐ โง ๐ โ ๐ ๐๐ โง ๐ โ ๐พ (12) Production capacities โ๐๐๐๐ ๐ โ ๐๐๐๐ โค ๐๐๐๐๐โ
๐ ๐ , ๐ โ ๐ผ๐ โง ๐ โ ๐พ (13) โ๐๐๐๐ ๐ โ ๐๐๐๐ โฅ 0.5 โ
๐๐๐๐๐โ
๐ ๐ , ๐ โ ๐ผ๐ โง ๐ โ ๐พ (14) โ๐๐๐๐ ๐ โ ๐๐๐ โค ๐๐๐๐๐โ
๐ ๐ , ๐ โ ๐ผ๐ โง ๐ โ ๐พ (15) โ๐๐๐๐ ๐ โ ๐๐๐ โฅ 0.5 โ
๐๐๐๐๐โ
๐ ๐ , ๐ โ ๐ผ๐ โง ๐ โ ๐พ (16) Inventory capacity โ๐๐๐๐ ๐ โ ๐๐๐ โค ๐ค๐๐๐๐โ
๐ ๐ , ๐ โ ๐ผ๐ค โง ๐ โ ๐พ (17) Constraints (10) and (11) define the decision variable ๐ ๐, stating that, within the network, an entity is only used (๐ ๐ = 1) if there is an ingoing flow to that same entity. These constraints exclude the suppliers, as they only have an outgoing flow. Constraints (12) to (17) set capacity limits. The maximum supply capacity is modeled through constraint (12). The maximum and minimum production capacity limits at mills โ constraints (13) and (14), and at factories โ constraints (15) and (16). Both in mills and factories, the production level must reach at least 50% of the total production capacity of that entity, for it to integrate the network. A minimum capacity ensures that mills and factories are not being used at an undesired low capacity and that the production levels are more evenly distributed. Constraint (17) sets the maximum inventory capacity for warehouses.
SUPPLEMENTARY MATERIAL 8 Transportation constraints โ๐๐๐๐๐ก๐ (๐ก,๐):(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ ๐ โ ๐ผ\(๐ผ๐๐๐) = โ๐๐๐๐๐ก๐ (๐ก,๐):(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ ๐ โ ๐ผ๐๐๐ ,(18) (๐, ๐)โ (๐๐๐๐๐๐ โช ๐๐๐๐๐๐๐ โช ๐๐๐๐๐๐) โง ๐ โ ๐พ โ๐๐๐๐๐ก๐ (๐ก,๐):(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ ๐ โ ๐ผ\(๐ผ๐ ๐๐) = โ๐๐๐๐๐ก๐ (๐ก,๐):(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ ๐ โ ๐ผ๐ ๐๐ ,(19) (๐, ๐)โ (๐ ๐ ๐๐๐๐ โช ๐๐ ๐๐๐๐๐ โช ๐๐ ๐๐๐๐) โง ๐ โ ๐พ โ๐๐๐๐๐ก๐ (๐ก,๐):(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ ๐ โ ๐ผ\(๐ผ๐๐๐๐) = โ๐๐๐๐๐ก๐ (๐ก,๐):(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ ๐ โ ๐ผ๐๐๐๐ ,(20) (๐, ๐)โ (๐๐๐๐๐๐๐ โช ๐๐๐๐๐๐๐๐ โช ๐๐๐๐๐๐๐) โง ๐ โ ๐พ The above constraints ensure that the flow of material going into an airport (18), seaport (19) and railway station (20) are transported to another airport, seaport and railway station, respectively. Furthermore, they ensure that the transportation is made through a plane, for constraint (18), a boat for constraint (19) and a train for constraint (20). Demand constraint โ๐๐๐๐๐ก๐ ๐ก:(๐ก,๐,๐,๐) โ ๐๐๐ก๐ถ๐๐ (๐,๐):(๐,๐,๐) โ ๐น๐ผ๐๐๐๐ = ๐๐๐, ๐ โ ๐ผ๐ โง ๐ โ ๐พ (21) The demand is modelled through constraint (21). Since the demand by each client must be satisfied, this constraint operates as a driver for all the networkโs flows.
SUPPLEMENTARY MATERIAL 9 2. Case Study Data This section describes the input data collection and treatment associated with each parameter. Demand Market demand is introduced through parameter ๐๐๐. The 14 clients considered and their respective annual demand of final product, in tons, is shown in Table 1. Due to a lack of information concerning the amount and location of stores in each country, each clientโs demand considered is the countryโs aggregated demand. Thus, the location for each client corresponds to the geographical center of the country. Table 1: Annual demand per client (๐๐๐). Demand (ton) Client / Year 2023 2024 2025 2026 2027 C1: Cambodia 4.5 5 5.5 6.1 6.7 C2: China 372.9 410.2 451.2 496.3 545.9 C3: India 363.6 400 440 484 532.4 C4: Indonesia 72.2 79.4 87.3 96 105.6 C5: Japan 32.1 35.3 38.8 42.7 47 C6: Malaysia 8.6 9.5 10.5 11.6 12.8 C7: Nepal 7.9 8.7 9.6 10.6 11.7 C8: Pakistan 59.9 65.9 72.5 79.8 87.8 C9: Philippines 29.2 32.1 35.3 38.8 42.7 C10: Singapore 1.5 1.7 1.9 2.1 2.3 C11: South Korea 13.2 14.5 16 17.6 19.4 C12: Sri Lanka 5.6 6.2 6.8 7.5 8.3 C13: Thailand 18 19.8 21.8 24 26.4 C14: Vietnam 25.6 28.2 31 34.1 37.5 Note that each clientโs annual demand means to represent the entire countryโs demand of final product, however, the values presented are merely indicative, since there was no available information on this matter. The values presented for 2023 were based on an apparel companyโs total net revenue and cost of goods sold, associated with the Asian continent (Levi Strauss & Co., 2022). From the sum of these values, a total revenue per client was obtained, considering the population size of each country, having been assumed that populationโs size is correlated with demandโs size. This data was used to estimate reasonable demand quantities in each market. According to 2017 forecasts, spending by the global middle class in Asia Pacific was expected to increase by 102% from 2020 to 2030, translating to an average of 10% increase per year (Kharas, 2017). Therefore, the forecasted demandโs annual growth was assumed to be 10%. It is important to mention that it was acknowledged that this forecast was made prior to the COVID-19 pandemic and the current war in Ukraine, events that caused and ensued significant disruptions in the worldโs population and economies. Nonetheless, according to Fengler et al. (2022), the global middle class in Asia has recovered strongly from both crises. The final productโs price per country, denoted as ๐๐, is presented in Table 2.
SUPPLEMENTARY MATERIAL 16 Transportation related parameters The airports, seaports, and railway stations mentioned above, and their respective annual hub cost (โ๐๐), can be consulted in Table 11. Table 11: Annual hub costs (โ๐๐). Transport Infrastructure (Airport (A), Seaport (SP), Railway Station (R)) Hub Cost (c.u.) A1: Austria 289 476 A2: Bangladesh 67 657 A3: Cambodia 96 351 A4: China 121 670 A5: Egypt 35 868 A6: India 70 329 A7: Indonesia 86 083 A8: Japan 346 583 A9: Malaysia 96 211 A10: Pakistan 76 659 A11: Philippines 91 991 A12: South Korea 167 384 A13: Sri Lanka 72 580 A14: Thailand 71 877 A15: Turkey 134 470 A16: Vietnam 94 804 SP1: Bangladesh 67 657 SP2: Cambodia 96 351 SP3: China 121 670 SP4: China 121 670 SP5: India 70 329 SP6: Indonesia 86 083 SP7: Pakistan 76 659 SP8: Sri Lanka 72 580 SP9: Vietnam 94 804 R1: Bangladesh (Dhaka) 67 657 R2: Bangladesh (Chittagong) 67 657 R3: China (Shenzhen) 121 670 R4: China (Shanghai) 121 670 R5: India (New Delhi) 70 329 R6: India (Mumbai) 70 329 R7: Pakistan (Karachi) 76 659 R8: Pakistan (Faisalabad) 76 659
SUPPLEMENTARY MATERIAL 17 The hub fixed costs displayed were obtained by assuming a hub cost for France (Mota et al., 2018) and considering Franceโs price level index 4 , specific for transport services (The World Bank, 2017). Then, through the price level index, for transport services in each country, their respective hub cost was obtained. As for the transport requirements of the supply chain, the company relies on an outsourcing strategy. Considering the extensive geographical footprint of its supply chain and the location of its clients, the company also counts on transport by truck, train, plane, and boat. The transportation costs for each transport mode in each country (๐ก๐๐๐ก) were calculated similarly to the hub costs and are presented in Table 12, per country. Based on a study carried out by the research institute Panteia (2023), the total cost per tonkm for each freight transport mode was obtained, for the Netherlands. Following the method used to calculate the hub costs, the transportation costs were obtained for each country of the supply chain where a flow could originate. Table 12: Transportation costs (๐ก๐๐๐ก). Transportation Cost (c.u./tkm) Country/Transport Mode Road Rail Air Sea Austria 0.38 0.014 0.18 0.0032 Bangladesh 0.09 0.003 0.04 0.0008 Cambodia 0.13 0.005 0.06 0.0011 China 0.16 0.006 0.08 0.0014 Egypt 0.05 0.002 0.02 0.0004 India 0.09 0.003 0.04 0.0008 Indonesia 0.11 0.004 0.05 0.0010 Japan 0.45 0.016 0.21 0.0039 Malaysia 0.12 0.005 0.06 0.0011 Pakistan 0.10 0.004 0.05 0.0009 Philippines 0.12 0.004 0.06 0.0010 Singapore 0.23 0.009 0.11 0.0020 South Korea 0.22 0.008 0.10 0.0019 Sri Lanka 0.09 0.003 0.04 0.0008 Thailand 0.09 0.003 0.04 0.0008 Turkey 0.17 0.006 0.08 0.0015 Vietnam 0.12 0.004 0.06 0.0011 4 The price level index considers World = 100. R9: Vietnam (Ho Chi Minh) 94 804 R10: Vietnam (Ha Noi) 94 804
SUPPLEMENTARY MATERIAL 18 The number of workers necessary for each transport mode per ton-km (๐ค๐ก) are presented in Table 12. Table 13: Number of workers necessary per transport mode (๐ค๐ก). Road Rail Air Sea Workers/tkm 2.67 15.56 0.07 11.59 The quantity of workers considered represent the division between the total amount of ton-km of transported freight in 2020 in the United States (Bureau of Transportation Statistics, 2020) and the respective number of employments in each transportation sector (Bureau of Labor Statistics, 2023). Distances The distances between the entities, corresponding to parameter ๐๐๐ ๐ก๐๐, were calculated through the application of the Euclidean distance formula, making use of each entityโs coordinates. This approach assumes a straight-line distance between two points. Water-related parameters Three different indicators were employed to measure the water impact across the various stages of the supply chain: water stress (of a region), water footprint (of raw materials), water consumption (for fabric and final productโs manufacturing and transport activities). The water stress indicator corresponds to the environmental indicator 6.4.2 built and used by FAO of the United Nations. The percentual level of water stress measured by FAO (2022) for the countries present in this supply chain, i.e. parameter ๐ค๐ ๐, is summarized in Table 14.
SUPPLEMENTARY MATERIAL 19 Table 14: Water stress level per country (๐ค๐ ๐). Country Water Stress (%) Austria 9.64 Bangladesh 5.72 Cambodia 1.04 China 41.52 Egypt 141.17 India 66.49 Indonesia 29.70 Japan 36.05 Malaysia 3.44 Pakistan 116.31 Philippines 26.25 South Korea 85.22 Sri Lanka 90.79 Thailand 23.01 Turkey 45.17 Vietnam 18.13 The water footprint for RM1 (cotton) and RM2 (hemp) per supplier is showcased in Table 15. This data corresponds to the parameter ๐ค๐๐๐.
SUPPLEMENTARY MATERIAL 20 Table 15: Raw materialโs water footprint (๐ค๐๐๐). Water Footprint (m3/ton) Supplier / Raw Material RM1 RM2 S1 4 267 724.5 S2 4 267 724.5 S3 2 398 2 183.1 S4 2 398 2 183.1 S5 4 457 - S6 9 724 754.6 S7 4 267 - S8 5 954 - S9 5 954 - S10 3 509 5 991.9 S11 4 267 - S12 4 267 - The study by Chapagain and Hoekstra (2005), in which the values considered for the water footprint of cotton were based on, distinguishes between the three types of water use, previously mentioned: blue water, for the withdrawal of water for irrigation or processing, green water, for the evaporation of infiltrated rainwater for cotton growth, and grey water for the volume of water necessary to dilute the pollution generated from the cropโs cultivation. Due to this blue, green and grey water measureโs specifications, it proved to be vital that the water footprint data was disaggregated on a per-country basis, since each countryโs climate, soil and agricultural practices are important factors to consider. The cottonโs water footprint presented represents the sum of the blue, green and grey water required to produce, in each country, 1 ton of seed cotton. Note that the study used did not include every country, therefore, for the missing data, the global average value of blue, green and grey water had to be assumed (Chapagain and Hoekstra, 2005). As for the raw material hemp, less information was available regarding its water footprint. Nonetheless, with the intent of establishing a fair comparison between both raw materials, an effort was made to obtain values that considered the same water impact as the one considered for cottonโs water footprint. The blue, green and grey water values for hempโs growing stage, per country, were calculated by Averink (2015), in a study conducted under the guidance of Prof. A.Y. Hoekstra. For the few supplier countries that lacked information on their blue, green and grey water impact, it was not possible to complete the gaps with the global average, as it was not available. For these cases, correspondent to S2 in Bangladesh and S6 in India, some research was conducted to obtain the predominant soil type of the countries. This parameter was considered a proxy between countries, and Bangladeshโs water footprint was assumed to be equal to Austriaโs water footprint while Indiaโs was assumed to be equal to Chileโs. According to Averink (2015), Austria presents a predominantly sandy loam soil, which is also very present in the region of Dhaka in Bangladesh (Islam et al., 2017), where S2 is situated. As for Chile, Averink assumes a predominantly clay loam soil which was found to be very similar to the soil of the land in Gujarat (Solanki et al., 2021), where S6 is located. The parameter soil was chosen as a proxy instead of climatic conditions because, according to
SUPPLEMENTARY MATERIAL 21 Averink (2015) and Mekonnen & Hoekstra (2011) the blue water attributed to raw material hemp is zero, as the production and yield of hemp does not increase with irrigation. Lastly, the water consumption values used for the production stages are presented in Table 16. As it was stated before, it was assumed that the transformation process into fabric and final product is equal for both raw materials. For this reason, it was also assumed that the water requirements for fabric (๐ค๐๐) and final product (๐ค๐๐๐) production are the same, despite the type of product being fabricated. Table 16: Fabric (๐ค๐๐) and final product (๐ค๐๐๐) water consumption per ton. Fabric Final Product Water Consumption (m3/ton) 780.9 390.4 The water consumed in the production of fabric and final product was based on a LCA conducted by Levi Strauss & Co. (2015) on a pair of jeans Leviโsยฎ 501ยฎ. According to this study, 68% of water consumption was related to the raw materialโs fiber, 6% came from the fabric production and 3% derived from the garment assembly and finishing, as well as the sundries application and packaging. The last impact was attributed to consumer care, which is not within the scope of the present work, thus it was disregarded. The sum of these three contributions was equaled to the total water footprint of a finished textile product of cotton, including the blue, green and grey water (Chapagain & Hoekstra, 2005). The value indicated for the water consumption, in Table 17, for the fabric represents 6% of this calculated total water footprint and the final product represents 3%. As for the water consumption associated with the transports, the midpoint category Water Consumption of the method ReCiPe 2016 available in Simapro was used. The values considered are displayed in Table 17 and correspond to parameter ๐ค๐๐ก๐ก. The references used for each type of transport mode will be detailed ahead. Table 17: Transport modeโs water consumption (๐ค๐๐ก๐ก). Road Rail Air Sea Water Consumption (m3/tkm) 5.09x10-3 8.34x10-5 3.42x10-4 7.01x10-6 Environmental characterization The characterization of the environmental impact of each stage of the supply chain was done through Simapro Ecoinvent 3 database version 9.3.0.3. For the raw materialโs crop cultivation and respective treatment stage, denoted as parameter ๐๐๐๐ ๐๐, two different raw materials were identified. For cotton, the reference โYarn, cotton {IN}| yarn production, cotton, ring spinning | Cut-off, Uโ was used, and the impacts are modelled according to Indian data. For hemp, due to a lack of information in the Simapro database regarding hemp fiber production, the reference โYarn, jute {BD}| yarn production, jute | Cutoff, Uโ was used. According to La Rosa and Grammatikos (2019), jute and hemp are very similar plants, therefore one can expect their impacts to resemble each other. Once again, the reference relies on an Asian-based countryโs data, Bangladesh. For the production activities in the supply chain, two references, regarding processes, were considered: โBleaching and dyeing, yarn {IN}| bleaching and dyeing, yarn | Cut-off, Uโ and โFinishing, textile, woven cotton {GLO}| finishing, textile, woven cotton | Cut-off, U}. Given that
SUPPLEMENTARY MATERIAL 22 it was assumed that the manufacturing of fabric and final product is the same, regardless of the type of final product being produced, it was reasonable to assume as well that the impacts associated with the production (๐๐๐๐ ๐๐๐ and ๐๐๐๐ ๐๐) are equal. An effort was made to select references that would not consider the same processes in their network, to avoid the double, and inaccurate, tally of an impact. Finally, the impacts related to the transportation operations of the supply chain (๐๐๐ก๐) were also considered through the following references: for air transport โTransport, freight, aircraft, medium haul {GLO}| transport, freight, aircraft, dedicated freight, medium haul | Cut-off, Uโ, for rail transport โTransport, freight train {IN}| transport, freight train, diesel | Cut-off, Uโ, for road transport โTransport, freight, light commercial vehicle {RoW}| processing | Cut-off, Uโ and for sea transport โTransport, freight, sea, container ship {GLO}| transport, freight, sea, container ship | Cut-off, Uโ. The environmental impacts are divided into eighteen midpoint categories, presented inTable 18 Table 18, alongside the code, that will be used to reference them, from this point onwards. For the normalization factors for each midpoint category (๐๐), Table 19 can be consulted. Note that ReCiPe 2016 also offers an indicator for water consumption. Nonetheless, this indicator does not provide the granularity that this study sought out for the supply chain activities under analysis. Table 18: Midpoint categories and codes. Midpoint Category Code Global warming GW Stratospheric ozone depletion SOD Ionizing radiation IR Ozone formation, Human health OFHH Fine particulate matter formation FPMF Ozone formation, Terrestrial ecosystems OFTE Terrestrial acidification TA Freshwater eutrophication FEU Marine eutrophication MEU Terrestrial ecotoxicity TE Freshwater ecotoxicity FEC Marine ecotoxicity MEC Human carcinogenic toxicity HCT Human non-carcinogenic toxicity HNCT Land use LU Mineral resource scarcity MRS Fossil resource scarcity FRS Water consumption WC
SUPPLEMENTARY MATERIAL 23 Table 19 - Units and normalization factors of midpoint categories. Midpoint Category Unit Normalization Factor Global warming kg CO2 eq 0,000125 Stratospheric ozone depletion kg CFC11 eq 16,7 Ionizing radiation kBq Co-60 eq 0,00208 Ozone formation, Human health kg NOx eq 0,0486 Fine particulate matter formation kg PM2.5 eq 0,0391 Ozone formation, Terrestrial ecosystems kg NOx eq 0,0563 Terrestrial acidification kg SO2 eq 0,0244 Freshwater eutrophication kg P eq 1,54 Marine eutrophication kg N eq 0,217 Terrestrial ecotoxicity kg 1,4-DCB 6,58E-05 Freshwater ecotoxicity kg 1,4-DCB 0,0397 Marine ecotoxicity kg 1,4-DCB 0,023 Human carcinogenic toxicity kg 1,4-DCB 0,0971 Human non-carcinogenic toxicity kg 1,4-DCB 3,20E-05 Land use m2a crop eq 0,000162 Mineral resource scarcity kg Cu eq 8,33E-06 Fossil resource scarcity kg oil eq 0,00102 Water consumption m3 0,00375 Other parameters Additional economic parameters were considered: a tax rate of 30% and an interest rate of 10%. Funding: This work is financed by Portuguese funds through the FCT - Foundation for Science and Technology, I.P., under the project UIDB/00097/2020 (CEGIST).
SUPPLEMENTARY MATERIAL 24 References Averink, J. (2015). GLOBAL WATER FOOTPRINT OF INDUSTRIAL HEMP TEXTILE. Bureau of Labor Statistics. (2023). Employment in Transport. Retrieved June 9, 2023, from https://explore.dot.gov/views/EmploymentinForHireTransportationEstablishmentsPrimarilyServingFreight/Table?%3Aembed=y Bureau of Transportation Statistics. (2020). U.S. Ton-Miles of Freight - Bureau of Transportation Statistics. Retrieved June 9, 2023, from https://www.bts.gov/content/uston-miles-freight Chapagain, A. K., & Hoekstra, A. Y. (2005). The Water Footprint of Cotton Consumption. https://www.researchgate.net/publication/228377230 FAO. (2021). FAO STAT. Retrieved April 3, 2023, from https://www.fao.org/faostat/en/#data/QCL FAO. (2022). AQUASTAT data. Retrieved May 3, 2023, from https://tableau.apps.fao.org/views/ReviewDashboardv1/country_dashboard?%3Aembed=y&%3AisGuestRedirectFromVizportal=y Fengler, W., Homi, K., & Caballero, J. (2022). Asiaโs tipping point in the consumer class. Brookings. https://www.brookings.edu/articles/asias-tipping-point-in-the-consumerclass/ ILO. (2022). LABOUR. Retrieved April 20, 2023, from https://ilostat.ilo.org/topics/wages/# Islam, Md. A., Hasan, Md. A., & Farukh, M. A. (2017). Application of GIS in General Soil Mapping of Bangladesh. Journal of Geographic Information System, 09(05), 604โ621. https://doi.org/10.4236/jgis.2017.95038 Kalkanci, M., & รzer, I. (2018). Developing a software calculating fabric consumption of various bathrobe models. Industria Textila, 69(5), 406โ411. https://doi.org/10.35530/it.069.05.1550 Kharas, H. (2017). THE UNPRECEDENTED EXPANSION OF THE GLOBAL MIDDLE CLASS AN UPDATE. https://www.brookings.edu/about-us/annual-report/. La Rosa1, A. D., & Grammatikos, S. A. (2019). Comparative life cycle assessment of cotton and other natural fibers for textile applications. Fibers, 7(12). https://doi.org/10.3390/FIB7120101 Levi Strauss & Co. (2015). THE LIFE CYCLE Understanding the environmental impact of a pair of Leviโs ยฎ 501 ยฎ jeans. Levi Strauss & Co. (2022). Levi Annual Report. Levi Strauss & Co. (2023). New Leviโsยฎ WellthreadTM x Outerknown Features Groundbreaking Cottonized Hemp - Levi Strauss & Co - Levi Strauss & Co. Retrieved March 30, 2023, from https://www.levistrauss.com/2019/03/11/new-levis-wellthread-xouterknown-featuresgroundbreaking-cottonized-hemp/
SUPPLEMENTARY MATERIAL 25 Mekonnen, M. M., & Hoekstra, A. Y. (2011). The green, blue and grey water footprint of crops and derived crop products. Hydrology and Earth System Sciences, 15(5), 1577โ1600. https://doi.org/10.5194/hess-15-1577-2011 Mota, B., Gomes, M. I., Carvalho, A., & Barbosa-Povoa, A. P. (2018). Sustainable supply chains: An integrated modeling approach under uncertainty. Omega (United Kingdom), 77, 32โ57. https://doi.org/10.1016/j.omega.2017.05.006 OECD/FAO. (2023). Cotton. OECD/FAO - Agricultural Outlook. Panteia. (2023). Cost Figures for Freight Transport-final report. Sarฤฑ, B., Zarifi, F., Alhasan, M., Gรผney, H., Tรผrkeล, S., Sฤฑrlฤฑbaล, S., Civan Yiฤit, D., Kฤฑlฤฑnรงรงeker, G., ลahin, B., & Keskinkan, O. (2023). Determining the Contributions in a Denim Fabric Production for Sustainable Development Goals: Life Cycle Assessment and Material Input Approaches. Sustainability, 15(6), 5315. https://doi.org/10.3390/su15065315 Solanki, C. H., Mistry, M. K., & Patel, M. S. (2021). Gujarat. In Geotechnical Characteristics of Soils and Rocks of India (pp. 231โ249). CRC Press. https://doi.org/10.1201/9781003177159-12 Szabo, B. (2023). Whatโs In a NumberPicking the Perfect Denim Weight - SOSO Clothing. . Retrieved April 15, 2023, from https://sosoclothing.se/whats-in-a-number-picking-theperfect-denim-weight/ The World Bank. (2017). Data Bank - World Bank. https://databank.worldbank.org/source/icp2017 United Nations. (2022). COMMODITIES AT A GLANCE: Special issue on industrial hemp.