bicycle lifecycle study

7/29/2019 Bicycle Lifecycle Study

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Alexeis Huaiquin Rosas, Daruska Miric Fuentes, Ryo Nakakido,Aurlien Delrieu & Pouya Saboktakin

Group 2 Bicycle Life-cycle Study


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Summary/Abstract

In this project the life cycle of a bicycle is studied. This study goes through the mostimportant steps in which an average bike is produced. Also the principal (raw) materials

are composed and used in this process as different inputs are considered as well as the

output flows in form of end product, manufacturing wastes and environmental emissions.

In the first step, the different sub processes needed for the manufacturing of the

most relevant materials of the bikes are shown, also showing the different output of

wastes generated. The construction process of a common bike is going to be explained

more accurately in the second part of the project. The same study regarding

environmental impacts analysis is performed on the raw material extraction process, the

use phase and the after-use phase of a bike.

To finish the explanation of the life cycle, the material usage and waste generation

of the maintenance of the bikes is considered, and in the last part of the project the final

destination of each part of the used bikes (which can be disposed in landfilled or recycled)

is shown. There is a discussion about a better environmental behavior in the life cycle of

the bicycles that can be produced by more recycling of the different parts and materials of

the bikes or the improvement of the efficiency of the energy systems implicated in the

whole process.


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CONTENTS

Introduction........................................................................................................................................ 3

Objective............................................................................................................................................. 4

Method ............................................................................................................................................... 4

1) Resource extraction phase ......................................................................................................... 4

Components and materials of an average bicycle ........................................................................................ 4

Process and emissions associated to the extraction of the materials ......................................................... 5

2) Process phase ............................................................................................................................. 8

Tires ................................................................................................................................................................ 9

Chain............................................................................................................................................................. 10

Aluminum wheels ........................................................................................................................................ 11

Assembly line (Cannondale bicycles, Pennsylvania)................................................................................... 12

Transportation ............................................................................................................................................. 15

3) Use phase.................................................................................................................................. 15

4) After-use phase......................................................................................................................... 15

Life Cycle Inventory (LCI) .................................................................................................................. 16

Life Cycle Impact Assessment (LCIA)................................................................................................ 17

Production Processes phase ........................................................................................................................ 17

Total lifecycle environmental impact per passenger-kilometer ................................................................ 17

References ........................................................................................................................................ 21


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INTRODUCTION

The life cycle is a framework, mainly used to study and identify the different

environmental impacts of a product, which in this case is a bicycle. All the stages of the

manufacturing of the process must be considered, including the processes that are

needed for the manufacture of the materials that compose a common bike, because those

stages also case environmental impacts, just like the main process of the bike

manufacturing.

The objective of this tool to detect the environmental impacts, from the extraction

of the materials to the disposal that allow us to formulate better policies, laws for the

waste emissions and ways in which companies may develop strategies for decreasing or

controlling the emission of wastes. Also it can be used for the comparison of different

product, realizing which one is more environmental friendly.

This project is about the life cycle of a bicycle which is made up off steel,aluminum, rubber and other materials that have their own manufacturing processes,

which necessitates consideration regarding the construction of the lifecycle of the bikes

due to the environmental impacts and the waste generated in the maintenance of this

vehicle.


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OBJECTIVE

The aim of this work is to research and describe the life cycle of an average bicycle,

considering the whole material flow from extraction phase to the manufacturing stage,

use and after-use phases in which the first two steps generate the most relevant

environmental impacts. Suggestions are made for the categorized impacts like recycling

and efficient energy consumption.

METHOD

The method used for the research and information gathering was mainly from

bicycles life cycle papers and books references, also using some internet related

information. Also in order to perform a comprehensive and detailed project, the work wasdivided in four topics- The resource phase, the process phase, the use phase & after-use

phase- and allocated to team members to be investigates and developed.

1)RESOURCE EXTRACTION PHASECOMPONENTS AND MATERIALS OF AN AVERAGE BICYCLE

Various materials are needed for the construction of a bicycle, and for fulfilling theentire life cycle of this transportation tool, it is needed to research all the chemical

compounds that constitute it, and the materials needed for each component for the

bicycle.

The principal parts of an average or regular bike are the tires, the gears and the

frame; meanwhile the subcomponents are the chains, the cranks and the shifters. These

components are made mainly of steel, aluminum, mild steel, rubber, foam and PVC. All

these materials contribute to give the bikes an average mass of 17 kilograms (simplel.ch

2009).

Table 1 shows the components that were mentioned and some other for an

average bicycle, including the amount of the average weight of needed for each

component:


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Table 1: Materials of each component of an average bicycle.

Component Material Average Weight [kg]

Frame Aluminum 2.50

Handlebar Aluminum 0.23

Stem Aluminum 0.23

Seat Post Aluminum 0.60

Bearings Steel 0.60

Wheels Aluminum 0.30

Steel 0.10

Tires Wire 0.19

Rubber/Plastic 0.56

Pedals Aluminum 0.3

Seat Rubber/Plastic 0.03

PVC 0.24

Foam 0.03

Chains Steel 0.45

Crank set Aluminum 0.84

Steel 0.36

V-Brakes Rubber/Plastic 0.14

Aluminum 0.28

Steel 0.28

Brake handle Aluminum 0.11

Rubber/Plastic 0.11

Cassette Sprockets Steel alloyed 0.53

Derailleurs Aluminum 0.15

Steel 0.60

Shifters Rubber 0.68

Cables Wire 0.15

Others Rubber 1.00

Aluminum 2.00

Steel 3.00

Other 0.5

Total All materials 17,09

Source: (M. Leuenberger, R. Frischknecht, Life Cycle Assessment of Two Wheels Vehicles 2010)

PROCESS AND EMISSIONS ASSOCIATED TO THE EXTRACTION OF THE MATERIALS

The materials used in the construction of each component are composed from

other raw materials that must be refined to get the materials that are used directly in thebikes. One example, the stainless steel that is used in many parts of the bikes, is obtained

from the iron ore, material that must be extracted and treated by several processes to

become the stainless steel.

In other hand, each process that transforms raw materials into useful materials to

be used to construct each component of the bicycles generates different wastes and


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emissions. At the same time, these processes need energy and other materials to go on.

For example for the reduction process of the iron ore, energy in form of heat is needed

which is normally generated by the burning of coal. The incineration of this material

generates emissions like carbon dioxide, carbon monoxide, etc.

Some of the input of materials and waste generation of the process to

manufacture the steel necessary to be used directly in the bikes is shown in the table 2.

This consists basically in a mining process for the extraction of the iron ore and

refinement.

Table 2: Steel manufacturing processes, emissions and raw material.

Steel

Process Material Input Material Output Waste Output

Iron ore extraction Hematite, magnetite Carbon dioxide, dust

Heating in absence of air Bituminous coal Carbon dioxide

Reduction of the ore Iron ore, coke, limestone Calcium silicateCarbon monoxide,

carbon dioxide

Removal of sulfurMolten iron, magnesium

powderMagnesium sulphide Carbon dioxide

Removal of carbonMolten iron, oxygen,

quicklime

Calcium silicate, calcium

phosphateCarbon monoxide

Alloy meltingMolten iron, chromium,

nickelCarbon dioxide

Annealing Stainless Steel Carbon dioxide

Source: R. Bhalla, Life cycle of a bicycle (2011). / http://www.ideasyncrasy.com/

The aluminum that composes the bicycles is obtained through the Bauxite mineral.

The Bauxite minerals, just like iron ore is underground, so mining process are required to

extract this mineral, and it must be refined and submitted to an electrolysis process. The

table below shows the sub process of the aluminum refinement and some of the wastes

generated.

Table 3: Aluminum manufacturing processes, emissions and raw material.

Aluminum

Process Raw Material Input Material Output Waste Output

Aluminum ore

extractionBauxite Carbon dioxide, dust

Bayers processCrushed bauxite, sodium

hydroxide solutionSilicon, lead, titanium,

calcium oxides Carbon dioxide

Precipitation

Sodium Tetra hydro

aluminate, Aluminum

hydroxideSodium hydroxide

Heat Aluminum hydroxide Water

Electrolysis

Aluminum oxide, cryolite,

carbon

Carbon monoxide,

carbon oxide, Aluminum



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Manufactured by the polymerization of vinyl chloride, chlorate hydrocarbon has to

pass many sub processes. It begins with the extraction of oil to obtain the hydrocarbon

that composes it. Many materials are needed for the production of this process, like

electrolysis and distillation, some of those process (and their materials and waste out

puts) are shown in the table 4:

Table 4: PVC manufacturing processes, emissions and raw material.

PVC

Process Raw material Input Material Output Waste Output

Crude oil

extraction

Shale Carbon dioxide, Sulfur

dioxide

Refined to

naphtha

Petroleum Volatile organic comp.

(Voc)

Electrolysis Rock salt

Mercury,

hexachloronbenzene,

hexachloronethane, PCB,

octachlorostyrene

Carbon dioxide

Steam cracking Naphtha (ethane, propane,

butane)

Carbon dioxide

Thermal

decomposition

Ethylenedichloride, copper

Chloroform,

hexachlorobenzene,

phthalene, zinc, copper,

dioxin

Polymerization Vinylchloridemonomer Dioxin

Compounding PVC additives

Injection molding PVC compound


Just as PVC, the foam is a polymer composed mainly by hydrocarbon, obtained

from petroleum at the first stages of the chain of process to manufacture it. Waste and

material output at shown in the table 5:

Table 5: Foam manufacturing processes, emissions and raw material.

Foam

Process Raw material Input Material Output Waste/Material Output

Crude oil extraction Shale

Refined to Naphtha Petroleum Volatile organic comp.

Reacting process Di-isocyanate polyol

PolymerizationPoly-isocyanate,

amine, metallic salt

ExpansionPolyurethane, carbon

dioxideCarbon dioxide

LayeringPolyurethane,

backing-paperPolyurethane

Cutting Polyurethane foam Foam



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The rubber is obtained from the natural rubber or resin, which is an organic

(hydrocarbon) polymer, adhered in the interior of some kinds of trees that are widely

cultivated. Some other sub processes are needed to improve the rubber mechanical

characteristics, their material inputs and wastes outputs are mentioned in the following

table:

Table 6: Rubber manufacturing processes, emissions and raw material.

Rubber

Process Raw material Input Material OutputWaste/Material

Output

Rubber tapping Rubber sap Latex

Mixing Latex acids Natural rubber

Co-polymerization Butadiene, styrene Synthetic rubber

Incomplete Combustion Crude oil, oxygen Carbon blackCarbon dioxide,

carbon monoxide

Mixing, re-milling, final

mixing

Natural rubber, syntheticrubber, carbon black,

sulfur, oil


Its important to know that almost all the processes to manufacture the materials needed

on the bikes need energy, in form of electricity or heat, and to generate that energy is

necessary the use of materials like coal or hydrocarbons for obtaining heat for example,

and the burning of these materials generate emissions of carbon oxides, sulfur oxides,

VOC, dust, etc. Also there is some processes mainly machinery that seems to not pollute,

but all them use electric energy at the end (for example precipitation need electric energyfor pumping purposes). This way, it can be said that performing more efficient process,

using less amount of energy in each part, less emissions can be achieved. Also the

recycling of the components of the materials of the bicycles would be helpful to decrease

the amount of raw material that need to be extracted, reducing the energy consumption

again and also the waste generation.

2)PROCESS PHASEAfter considering the environmental emissions of the raw material used in

manufacturing a bicycle such as steel, aluminum, PVC, tire and plastic, in this chapter as a

next step the aim is to focus on production procedure of bicycle parts such as tires, chain,

aluminum wheels, body frame and of course considering the assembly line as a whole

image where all these parts meet to end up as an end product.


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The transportation of the final product is considered also in this chapter as the very

last step before reaching the customer.

TIRES

Tires first were invented in 1888 by John Dunlop; Until the world war 2 bicycle tires

were organic but by 1960s synthetic rubber became standard and modern bicycle tire

have been made of it ever since. Bike tires are made by the combination of rubber, nylon

and bulletproof Kevlar.

Rolling machines or banbury mixers are fed by rubber stocks and other chemicals such as

silica, Zink oxide, sulfur and also carbon black to increase ti res density, elasticity and

durability. Nylon could be added in this stage or another separate phase using similar

equipment. The milling process shapes the rubber into flat, long strips and ready to beassembled by a highly automated process in which components are assembled on a

rotating drum.

Exposing heat and hazard of sudden inhale of chemicals while respiration apart from the

mechanical risks show the environmental impacts of the wastes energy in form of heat

also chemical emission and leach. Besides machinery regular work & maintenance have oil

leach and pollution also.

Tire builders utilize solvents, such as hexane, which allow the tread and plies of rubber to

adhere. Exposure to the solvents is an area of concern for workers and of course shouldbe considered as an environmental impact.

In almost the last stage, curing press aims to transform the tacky and pliable material to a

non-tacky, less pliable, long-lasting state by utilizing steam to heat (up to 180 degrees for

3 minutes) or cure the tire. This would also reveal waste in form of heat and water

consumption.

Inspection and testing is performed on random tires focusing on punching and pressure

resistance. There are machines simulating the road situation which test tires non-stop for

2 or 3 days in a row and the energy consumption is considerable in this phase.

The following table(s) considers the environmental impacts of the consumption of

electricity and paper regarding their indirect environmental impacts also.


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Table 7: Tire manufacturing processes and environmental impacts

Process/Phase Tool/Machine Raw material Environmental impact

Compounding and

Banbury mixing

Heavy rolling

machine/Banbury mixer

artificial rubbers,

Mineral oil, silica, Zink-

oxide and sulfur

Energy consumption /

Energy waste (heat) /

Chemical leach

Milling Heavy rolling machine Nylon Energy consumption

Component Assembly

and BuildingRotating drum Glue, solvents (hexane)

Energy consumption /

Energy waste (heat)/

Chemical leach

Curing and Vulcanizing Heat press

Energy consumption

Energy waste (heat)/

water

CHAIN

A bicycle chain is essentially a roller chain that is designed specifically to transfer pedal

power to the bicycles rear wheel. The manufacturing process starts with a punch press

which cuts and shapes the steel into chains inner links. Then the links bake in 1500

Fahrenheit degrees in order to gain more strength. Baked links followed by fast cool down

of baked steels strengthens the steel more. Hence lots of energy in form of heat is wasted

in this phase.

As the next step chemicals such as ceramic and silica powders plus little amount of water

are all mixed with links in a donut shape container which polish the links. Then these links

take a chemical bath which gives them a nickel Teflon veneer to increase resistance

against corrosion and by smoothing the surface allow chain move easily over gears

brackets. Hence the chemical leach and evaporation is considered as a significant impact

despite the low possibility.

Assembly machine in the next step forms the chain beautifully by using outer and inner

links in a unique order and connects those using spins and rings. Hot oil bath as the next

step lubricate the chains and make them ready for the very last step in the process whichis cutting by a laser machine.

Then different length and model chains are being packed and ready to send. Table 8

expresses more about the raw material and tools in use in each step as well as

environmental impacts.


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Table 8: Chain production processes and environmental impacts

Process/Phase Tool/Machine Raw material input Environmental impact

Cutting links Punch-press machines Steel sheet Energy consumption

Cooking links Furnace Fuel/Coal

CO2 emission

Energy waste (heat)

Polishing links Doughnut-shaped mixer ceramic & silica powder Chemical Leach

Anti-corrosion veneering Chemical pool Nickel Chemical leach

Lubrication Hot oil bath OilOil leach

Energy waste (heat)

cutting Laser cutterEnergy consumption

Energy waste (heat)

packagingPapers, plastic bags,

cartons

Paper consumption

Plastic penetration into

the environment

ALUMINUM WHEELS

In a very simple process aluminum tubes are bent with bending machines to form a

circular shape. Right after measuring the rim, a cutting tool separates the rings and for

almost a rim. Two ends of a rim is joined by an automatic welding machine which cause a

welding line sign on the rim hence a sharp vibrating cutting tool smooth the weld line. So

far the automation involved in the processes is considered as energy use sources as well

as the probable maintenance chemical and oil uses (and leach) are environmental

impacting issues.

More hazardous impacts happens before the end welding of rims when the acid bath

removes the dust and other contaminants from the rims surface and later on the multi-

phase heating process in order to increase strength of the metal (that re-structure the

molecules of aluminum) which consumes electricity or fossil fuels or coal also emit Co2,

So2 and other particles and gases in to the air.

After all these processes comes up the anti-corrosion coating in chemical pools using an

electrical charge to draw the coating particles onto the rims surface. The process is called

Anodization.

A computer guided machine shaves off the amount of anodized metal for nearly one third

ofthe rims surface. This creates a smooth perfectly flat area for the brake pads to grib.


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Another computer guided machine drills holes for tiny aluminum nipples which hold the

aluminum spokes to the rim.

Then a manual phase of assembling wheels is performed then lacing the wheel in which

spokes are fixed and connected in rims holes. Truing the wheel is the important step in

aligning the wheel by adjusting the spokes using a specific wrench until the wheel is finally

trued.

After the manual phase, robots make any necessary tensioning adjustments afterwards.

Depending on the model a wheel can have between 10 to 46 spokes.

Overall, table below tells more about the details regarding the steps priority and

environmental impacts.

Table 9: Environmental impacts of manufacturing aluminum wheels

Process/Phase Tool/Machine Raw material Environmental impactBending Bending machines Aluminum tubes Energy consumption

cutting Cutting machine Energy consumption

Acid wash Acid bath Acid(s) Chemical Leach

Heating Heating room

Energy consumption

(after burn gases

emission)

End welding Welding machineEnergy consumption

Energy waste (heat)

Weld line Milling Milling machine Energy consumptionAnti-corrosion coating Chemical pool Chemicals Chemical leach

Grid line Milling Milling machine Energy consumption

Spokes installation (Manual)

TestingAlignment testing

machinesEnergy consumption

packagingPapers, plastic bags,

cartons

Paper consumption

Plastic penetration into

the environment

ASSEMBLY LINE (CANNONDALE BICYCLES,PENNSYLVANIA)

Having Profile and pipe as inventories, first of all requires transportation inside the site to

be places in warehouse and then to the cutting phase. This would need electricity or fuel


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to provide these transitions besides the emitted gases in case of using lift-trucks with

diesel engines for instances.

CNC machines in the cutting step make parts out of aluminum or steel pipes which would

make even more sense when a plasma or laser cutter create accurate holes and channels

on tubes. Energy consumption and energy waste in form of heat is considerable at this

stage.

In order to give the group the number of tubes as a frame, tack welding now gives the

general shape of the frame which also allows the parts to be handled as one unit from

now on. At the welding department attachments are completed and would be completed

by a sanding process which removes all imperfections in welded parts. This ensures there

is a nice smooth transition between tubes where the weld I concerned.

At this procedure also heat treatment is performed to increase the strength of the frame.

Then in a manual phase the alignment of the frame is tested.

Some extra machine works for dressing appropriate surfaces, wholes, etc. is done before

the frames are sent for painting.

A neat frame with no oil or any material on its surface, would end up with a better

painting quality, hence a chemical bath is done to prepare the frames respectively.

After the painting phase which in this case in done manually, frames are sent to heating

room to be then transferred to the decal room where all decals are applied manually.

Decaled frames are then back to the painting room to get this time a protection layer over

decals. Now the frame is ready and from now on all other extra parts mentioned in the

previous parts meet here to form the end product.

In pre-assembly location swing arms or any other hardware such as shock absorbers are

attached to the main frame. Then in parallel components for handle bar which are made

up of shifters, grips are put together to be fixed on the main frame later on in the

assembly line.

On assembly line the hanging bike moves along and each part such as, handle bars,wheels, gears, shifters, chain, any other small component is put on and fixed respectively.

After the quality control, bikes are ready for packing in which paperboards, cartons and

plastic bags are used. The overall flow can be grasped from the chart below.


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Chart 1: Assembly line scheme

Source: Ruey-Shun Chena, Mengru (Arthur) Tu (2009), Development of an agent-based system for

manufacturing control and coordination with ontology and RFID technology

Table 10: Environmental impacts of assembly line of bicycles

Process/Phase Tool/Machine Raw material Environmental impact

In-house transportation Lift trucks Fuel CO2, SO2, etc emission

Cutting Cutting machine Energy consumption

Accurate channeling Plasma or laser cuttersEnergy consumption/

Energy waste (heat)

Tack welding Welding guns Energy consumption

Welding Welding machines ElectrodesEnergy consumption

Energy waste (heat)/ water

Sanding Sanding machines Energy consumption

Heat treatment Heating room Electricity / fuel

Energy consumption/

Energy waste (heat)

CO2, SO2, etc emission

Dressing machinery Drilling machines Cooling oils/liquidsEnergy consumption/

Cooling liquid leach

Frame wash Chemical pool Chemicals Chemical leach

Painting Paints Chemical spray leach

Decaling Glued decalsChemical penetration into

the environment

Decal fixing Fixator sprays Chemical spray leach

Assembly Assembly line electric tools Energy consumption

Packaging

paperboards,

cartons and plastic

bags

Paper consumption/

Plastic penetration into the

environment
http://www.sciencedirect.com/science/article/pii/S0957417408006799http://www.sciencedirect.com/science/article/pii/S0957417408006799http://www.sciencedirect.com/science/article/pii/S0957417408006799http://www.sciencedirect.com/science/article/pii/S0957417408006799


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TRANSPORTATION

The process phase of the bicycles life cycle does not end here and actually there is one

more step before starting the use phase and that is transportation of the end products

to the consumption area. Transportation can be done directly to the sport or toy stores

and/or to the local distribution centers.

The main environmental impact is of course matter of exhaust gases emitted into the

atmosphere by truck and container. Considering the maintenance of these vehicles would

add more items to these impacts as well.

3)USE PHASEBicycle is known as a green transportation mean hence it is a difficult task to mention the

direct environmental impacts generated during the use phase. The motive power source

in the bicycle is produced by human muscle power where the required impulsion energy isobtained from food consumption. Emissions producedby bicycle use in this phase(CO2eq,SO2, PM, CO, HC, NOx and Pb) are largely zero and do not consider emissions required by

the production of food.

But the indirect impacts through using of spare parts like tires, brake grips, wheels,

etc. should be considered and the reason is the increase of the order in the manufacturing

phase where the impacts have been already mentioned. The maintenance process uses

oils, lubricants e.g. grease and other chemical items which cause soil pollution for instance

because of leaching.

4) AFTER-USE PHASENow a days wastes utilization is a major issue to get clean and healthy

environment. The production of waste tires throughout the world is estimated to be

1billion tons tires-all types- per year (Williams, 2005).

As the environmental pollution caused by waste tires has become a rigorous issue

in global environment protection, Pradhan and Singh (2011) discussed that termal

pyrolysis of tire-in general- by batch reactors at 600C would lead to the pyrolytic oil thathas significantly higher calorific value and thus can be used as an alternative to fossil fuel

after proper treatment.

Wang et al (2011) also discussed the use of recycled tire crumb rubber as an

alternative electrode material in microbial fuel cells as the tire particles showed satisfying


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conductivity after 2-4 layers of graphite coating. This is a good example of bike tires after-

use phase.

Bicycle parts that are made of steel can be recycled as scrap metal, specifically as

ferrous metal, in the municipal drop-off center or scrap metal center. Recycling it is

important, because for every ton of steel recycled, 2500 pounds of iron ore, 1400 pounds

of coal and 120 pounds of limestone are conserved.

The importance of recycling aluminum is that the energy saved by recycling 1 ton

of aluminum equals the amount of electricity used by a typical home within a 10 years

period.

Also, if the bike can still be used, there is possibility of resale in 2nd

hand markets,

etc. also the spare parts might be used after reassembling.

LIFE CYCLE INVENTORY (LCI)Seen from a general form, Table 11 shows the material inventory used in the

bicycle production process, also shows the material inventory for electric bike, electric

scooter, motorcycle and bus.

The production process, for all the vehicles, consists of the following stages:

mining or extraction of raw materials, processing those raw materials into usable refined

material, fabricating refined materials into individual parts, and assembling the parts into

the final vehicle. The material inventory was determined from leading vehicles producing

companies in China.1Table 11: Inventory of materials in vehicles production process

Source: Cherry, C.R. (2009). Comparative environmental impacts of electric bikes in China. Transportation

Research Part D 14, 281-290.

1Cherry, C.R. (2009). Comparative environmental impacts of electric bikes in China. Transportation

Research Part D 14, 281-290. Page 2.


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During the manufacturing process of bicycles are generated various types of

emissions. It is important to specify that the types included de emissions due to the

mining and production of ferrous and non-ferrous metals, and the production of plastic

and rubber. The inventory between production process and environment are: Air

pollution (SO2), Air pollution (PM), Greenhouse gas (CO2eq), Waste water and Solid waste.

LIFE CYCLE IMPACT ASSESSMENT (LCIA)

PRODUCTION PROCESSES PHASE

Some of the wastes, generated in the stages mentioned before, come into contact

with the environment causing an impact on this. In the Table 12, the impact in the

environment and the energy use for bicycle, electric bike, electric scooter, motorcycle and

bus is illustrated. These emissions were calculated using the material inventories fromproducing companies in China.

The environmental impact considers data reported in industrial statistical

yearbooks, to identify emission intensities (kg pollutant per kg of material produced). Also,

does not include transportation logistic impact.

Table 11: Environmental impact in vehicles production process



As seen in the table, the waste water is a major cause emissions impact in the bicycle

process. In this, control can be focused or can design strategies for decreasing

environmental damage.

TOTAL LIFECYCLE ENVIRONMENTAL IMPACT PER PASSENGER-KILOMETER

In this point it is show the average emissions produced, in the production and use

phases, per passenger kilometer traveled for bicycle, electric bike, electric scooter,


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motorcycle and bus, this is an important comparison of the environmental impacts. Table

13 gives the emissions of both faces together.

Several assumptions were made to develop Table 13, which are2:

- Lifespan of 197000 km, 1000000 km, 20000 km, 60000 km and 50000 km for car, bus,bicycle, motorcycle and electric bike respectively.

- Average load factor of 1-3 pax for car, 25-75 pax for bus, 1 pax for bicycle, 1-2 pax formotorcycle and 1-2 pax for electric bike. This factor assumes generally uncongested

city.

- 100% recycle rate and one battery every 10000 km for electric bikes and one batteryevery 3 years or 250000 km for buses, one battery every 3 years or 75000 km for car,

one battery every 3 years or 18000 km for motorcycle.

Table 12: Environmental Impact per passenger-kilometer



Table 13 shows that the most important bicycle emission is carbon dioxide, henceit can help designing a strategy to eliminate or reduce this environmental impact. The

vehicle that make more emissions of carbon dioxide is the car, and as expected the bicycle

the more friendly with the environment. So it can be said that the bikes are the most

efficient option of transportation, in energy consumption per distance terms.

2Cherry, C.R. (2009). Comparative environmental impacts of electric bikes in China. Transportation

Research Part D 14, 281-290. Page 7.


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Discussion

As all the processes associated with the manufacturing of a bicycle which cause

different environmental impacts were researched; these impacts can be detected by the

realization of a life cycle (in this case for the bikes), tool that allow us to organize andclassify the different stages of the process of the bicycle manufacturing, from the

extraction of the raw materials that compose the bikes, through the manufacture this

vehicle, and until the final destination, that could be the disposal in landfill, recycling or

resale.

There are inputs in the bicycle life cycle in form of energy and raw material as well as

outputs if form of disposed parts or wasted energy hence production optimization and

reuse or recycling mean to keep the material in the cycle and prevent them leaving it.

These stages are shown schematically in the following figure:

Fig 1: Diagram of the life cycle of the bicycles.

Source:http://www.apartmenttherapy.com/conduct-a-mini-life-cycle-asse-124497
http://www.apartmenttherapy.com/conduct-a-mini-life-cycle-asse-124497http://www.apartmenttherapy.com/conduct-a-mini-life-cycle-asse-124497http://www.apartmenttherapy.com/conduct-a-mini-life-cycle-asse-124497http://www.apartmenttherapy.com/conduct-a-mini-life-cycle-asse-124497


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The most important environmental impact detected in the whole chain of process

was the emission of carbon dioxide, the most relevant greenhouse gas of these days. The

major part of carbon dioxide (as carbon monoxide, sulfur dioxide, and others) emissions

have their source in the manufacture of the bike itself, and in the manufacture of each of

the different materials that compose the bicycles, considering the extraction and refining

of the raw materials, works that have their own sub processes that could be heating,

cooling, transport, precipitation, distillation, and many others, and each one of those

processes need energy in form of heat or electricity to be performed.

These emissions of waste could be direct or indirect. A direct way to cause an

environmental impact through the emissions of carbon dioxide could be for example

during the transportation of raw materials, job that must be done by vehicles that use fuel

and generate carbon dioxide. The same goes for industrial processes like heating that

could be done by heat exchangers or furnaces, burning hydrocarbons like fuel oil, coal, or

many others sources, generating carbon dioxide, carbon monoxide, sulfur dioxide, etc.

Also there are other kinds of direct waste emissions that must be mentioned, these are

the industrial solid wastes, which final destination are principally in landfills, and the

industrial liquid wastes, that are almost always treated in the plant of process to be

discharged in rivers or in the sea.

The indirect way of polluting consists in all the process that not generates

emissions directly, but uses other sources of energy like the electricity to perform their

jobs. An example of this is the pumping of fluids (which dont generate emissions), most of

the pumps need electricity for working, and this electricity could be generated at the end

by thermo electric power plants, which burns hydrocarbons and pollute greenhouse

gases.

This lead us to the conclusion that investing in more efficient process in the whole

chain of the bicycle manufacture process, will help to decrease the energy consumption

(decreasing the amount of hydrocarbons burned) and decreasing the amount of

greenhouse gases generated. An example of investment could be the installation of

insulation in pipelines, decreasing the leakage of heat.

Another considerable step about the life cycle realized is the final stages and the

important of recycling the parts. This would help decreasing the amount of raw material

input in the cycle. Consequently the amount of greenhouse gases and waste generated in

the first stages raw material extraction and production would also decrease.


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References

Cherry, C.R. (2009). Comparative environmental impacts of electric bikes in China.Transportation Research Part D 14, 281-290.

Debalaxmi Pradhan and R. K. Singh (2011), Thermal Pyrolysis of Bicycle Waste TyreUsing Batch Reactor, International Journal of Chemical Engineering andApplications, Vol. 2 , No. 5 , October 2011

Ruey-Shun Chena, Mengru (Arthur) Tu (2009), Development of an agent-basedsystem for manufacturing control and coordination with ontology and RFID

technology.

Heming Wang, Matthew Davidson, Yi Zuo, Zhiyong Ren.Recycled tire crumb rubberanodes for sustainable power production in microbial fuel cells.

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