Design Life-Cycle

Ryan Culp

Samuel Dale, Kiel Trinidad

Design 40A

Professor Christina Cogdell

Raw Materials

An Optical Fingerprint Scanner is a specific type of Scanner that uses an image sensor, light source, and glass lens and is encased in a plastic housing to scan the ridges of a fingerprint. (Basil Abbas) They are small in size and can be relatively cheap to buy. However, this is not to say that making these devices is an easy process. There are many steps and materials involved throughout the lifecycle of an optical fingerprint scanner that prove it to be an unsustainable device. 

The first stage in the lifecycle of this device is the acquisition of materials. In this stage, all of the materials necessary to build the scanner are gathered. The first piece that requires materials is the glass lens. Glass is made from melting sand, however, to lower the melting point other materials are mixed in. This includes Sodium Carbonate and Calcium Carbonate. (Floyd Glass & Window.) To collect these materials, huge machines called “Dredging Ships” have to scrape in from the ground.(Oli Brown and Pascal Peduzzi) These ships are made mostly out of steel. There are also continuous mining machines that collect the materials like sodium carbonate. These machines are also made of steel and other conductive metals and semiconductors for the electronics.(Trona; Conductive Materials: How It Works, Application & Advantages; Gaea  Marelle Miranda) These same materials are used in most other mining equipment as well for gathering the rest of the raw materials. The next piece of the scanner that requires the gathering of raw materials is the light source. 

The LED light is the second necessary part of an Optical Fingerprint Scanner. A single LED light is a small device that can take up a decent amount of materials. The materials of the main components are only made from a conductive metal, and a semiconductor, such as silicon. (The Engineering Mindset) These materials also have to be mined by machines that are similar to the ones before that are made mostly out of steel. These machines also have to run on some type of fuel just like any other large machine. In addition, a housing for the LED uses up more materials. The color of the housing will decide which materials are used, but the following materials are used in the creation of it; Phosphide, Arsenide, Gallium, aluminum, and Carbide. (The Engineering Mindset) However, the housing material may not be necessary for the fingerprint scanner as it is primarily used to distinguish the color of the light, which is not a necessary function in the construction of the fingerprint scanner. The next and arguably most important part of the fingerprint scanner is the Image Sensor. 

There are multiple kinds of image sensors, however CCD will be the one focused on in this paper. A basic explanation of what materials are involved in the CCD is as follows:

CCDs are silicon-based sensors comprised of a silicon substrate, and a deposited epitaxial layer. An integrated circuit it etched onto the silicon surface to make an array of pixels, which count the number of incoming photons and convert them to photoelectrons. These electrons are transferred down the sensor until they are readout and digitized to display an image on the imaging software. (Silicon-Based Ccds: The Basics)

The materials in this part such as silicon and conductive metals are also mostly mined with the same machinery used in the previous parts as well. In addition to these materials, there is also photosensitive resin, which requires Monomers, Oligomers, and Photoinitiators to be made. (What Is 3D Printer Resin?) These are synthetic materials that are made in labs. CCD’s also need pigment powders that are three specific colors; red, green, and blue. (Thailand Community) These materials are what is required for the initial acquisition of materials for an optical fingerprint scanner. 

The next step in the life cycle of the fingerprint scanner is the manufacturing of the product. The glass lens does not need a large of materials when manufacturing as it simply needs to be heated up. (Floyd Glass & Window) This Machine is mostly made out of steel. The LED light is another part of the fingerprint scanner that does not need any extra materials in assembly. The PLA plastic housing is also not overly intensive on extra materials during the manufacturing process. It mostly just needs to be heated up. It then needs to be fit into a mold, which can be made out of metal. (ABS Plastic: Definition, Composition, Properties and Uses.) This mold can be used multiple times reducing the amount of metal used in the process. However, the CCD requires some extra materials aside from metal machinery. During the process, the silicon wafer is rinsed in both tap water and purified water. (Thailand Community) In addition, it also needs to be dipped in acid to eat away excess conductive material aside from the necessary circuitry. After these parts have all been produced, they need to be transported.

The transportation of these materials and the scanner itself rely on all major forms of transportation including trucks, trains, ships, and planes. (Transportation: Delivering the Plastic Products You Can’t Live Without.)These all are made mostly out of steel just like the mining machines. Similarly to the mining machines, these machines must run on fuel as well. In addition to the vehicles, these products are packaged to not damage them on the way to their destination. Aside from using these vehicles and the packaging, there are no extra materials necessary to transport them. However, once the scanners arrive at their final destination, they must receive proper care to work properly.

The third stage of the life cycle is the use, reuse, and maintenance of the product. What helps optical fingerprint scanners to work at their best is to make sure they are cleaned properly. The proper technique can be found on Bayometric.com. This is important since image sensors are used as the technique for capturing fingerprints. If the glass is smudged or scratched, then the device will not work properly and may create incorrect results. To clean them properly, a lint-free cloth needs to be used. These are made out of polyester and nylon. (What Is a Lint Free Cloth?) Some kind of canned air to blow off excess lint is also recommended, and these cans of air usually contain chemicals such as difluoroethane, trifluoroethane, tetrafluoroethane, or butane. (Anne Marie Helmenstine) The last thing needed to keep this product clean is acetone according to Bayometric.com. Even with the proper care, it is inevitable that eventually it will break or be thrown out, which leads the the final stage of the life cycle which is the recycling and disposal of the product. 

Recycling electronics depends on the location and the procedures of recycling in any given area. Many materials can be thrown into a landfill where they will not break down or degrade any time soon. (Plascon Plastics) The United States only recycles about 35% of electronics. (Mounting E-Waste Is Harming the Planet. Here’s How We Solve the Problem) However, if the proper procedures are implemented, then many of the materials can be recycled. The system of recycling electronics can be discovered from (How Is E-Waste Recycled: The Recycling Process). First, the electronics are sorted by hand by employees working at the recycling center.  Then, a big machine known as a “Shredder” shreds the electronics up into smaller bits. These bits then travel under and large magnet which pulls up the metals from the shredded pieces. After this, all the different kinds of plastics are separated by having the remains run through water. Even after those steps, there is still leftover material that may be harder to separate or recycle. Lead that contains glass can also be sent off to smelters to melt it down and use in new products. 

This assignment required a large amount of research and a detailed examination of many different sources. This occasionally led to coming to a halt in my research at times. Failures and assumptions were part of my process as well. I struggled to be certain if I broke everything down to the purest forms of its building blocks. It often felt that once I found out what something was made of, those materials were made from a combination of other materials. I also made some assumptions such as saying the metal mold was reusable. However, it has helped me to understand how difficult it is to know exactly what materials and the process in which everyday items are made. 

This Project helped to clarify how much goes into a single product. It also opened my eyes to how even a small device that does not require large amounts of immediate power can still use up so many resources and materials to be created. Through the full process of the lifecycle, it is clear to see that it is not at the level of sustainability that it needs to be. Numerous materials are mined with giant machines that run on unsustainable fuels. More materials and chemicals are then used to manufacture the product itself. Distributing optical fingerprint scanners also uses many large vehicles that are also running on unsustainable fuels. There is the potential to recycle these products, but it is not done at the levels that are necessary to make a difference. Change needs to happen, and the lifecycle of all products alike needs to be cleaned up.

Works Cited

Abbas, Basil. “4 Types of Fingerprint Scanners: Deep Dive into How They Work.” ClockIt, 1 Sept. 2023, clockit.io/fingerprint-scanner/. 

“ABS Plastic: Definition, Composition, Properties and Uses.” Ruitai Mould, 15 Dec. 2023, www.rtprototype.com/what-is-abs-plastic/. 

Brown, Oli, and Pascal Peduzzi. “Driven to Extraction: Can Sand Mining Be Sustainable?” Sustainability Accelerator, 30 May 2019, accelerator.chathamhouse.org/article/driven-to-extraction-can-sand-mining-be-sustainable/. 

Clark, Mary. “How to Clean Your Fingerprint Scanner Device.” Bayometric, Bayometric, 30 June 2020, www.bayometric.com/how-to-clean-your-fingerprint-scanner-device/#:~:text=Though%20the%20fingerprint%20reader%20is%20quite%20tolerant%20of,them%20a%20longer%20lifespan%20and%20sustain%20their%20workability. 

“Conductive Materials: How It Works, Application & Advantages.” Electricity, 26 Oct. 2023, www.electricity-magnetism.org/conductive-materials/#:~:text=Types%20of%20Conductive%20Materials%201%20Metals%3A%20Metals%20like,a%20certain%20temperature%2C%20known%20as%20the%20critical%20temperature. 

The Engineering Mindset. “How Led Works - Unravel the Mysteries of How Leds Work!” YouTube, YouTube, 30 Apr. 2023, www.youtube.com/watch?v=O8M2z2hIbag. 

Floyd Glass & Window. “How Glass Is Made.” YouTube, YouTube, 22 June 2011, www.youtube.com/watch?v=IjNusHQOhTM. 

Helmenstine, Anne Marie. “Canned Air Isn’t Actually Air.” ThoughtCo, ThoughtCo, 28 Nov. 2022, www.thoughtco.com/whats-in-canned-air-3975941. 

“How Is E-Waste Recycled: The Recycling Process.” Greentumble, 18 Apr. 2021, greentumble.com/how-is-e-waste-recycled-the-recycling-process. 

Memon, Shahzad & Sepasian, Mojtaba & Balachandran, Wamadeva. (2009). Review of finger print sensing technologies. 226 - 231. 10.1109/INMIC.2008.4777740. 

Miranda, Gaea  Marelle. “How Are Semiconductors Used in Mining?” AZoMining, 18 Aug. 2020, www.azomining.com/Article.aspx?ArticleID=1463. 

“Mounting E-Waste Is Harming the Planet. Here’s How We Solve the Problem.” World Economic Forum, www.weforum.org/agenda/2021/01/consumer-electronics-managing-e-waste/#:~:text=U.S.%20households%20now%20produce%20about%2010%25%20less%20electronic,only%20about%2035%25%20of%20U.S.%20e-waste%20is%20recycled. Accessed 6 June 2024. 

Plascon Plastics. “What Is PLA Plastic? | What Are the Pros and Cons of This ‘Green’ Plastic.” YouTube, YouTube, 19 Mar. 2021, www.youtube.com/watch?v=Iw191pVHnQo. 

“Silicon-Based Ccds: The Basics.” Teledyne Princeton Instruments, 30 Nov. 2021, www.princetoninstruments.com/learn/camera-fundamentals/ccd-the-basics. 

Thailand Community. “How It’s Made - CCD Semiconductors.” YouTube, YouTube, 2 Mar. 2014, www.youtube.com/watch?v=rRPXwXVXdVg. 

“Transportation: Delivering the Plastic Products You Can’t Live Without.” UP, www.up.com/customers/track-record/tr020420-transportation-and-plastics.htm. Accessed 6 June 2024. 

“Trona.” Wyoming Mining Association, 12 Mar. 2020, www.wyomingmining.org/minerals/trona/#:~:text=Trona%20is%20mined%20underground%2C%20using%20heavy%20equipment%20like,is%20then%20carried%20to%20the%20surface%20and%20processed. 

“What Is 3D Printer Resin?: HATCHBOX.” HATCHBOX 3D, www.hatchbox3d.com/pages/photopolymer-resin. Accessed 6 June 2024. 

“What Is a Lint Free Cloth?” In The Wash, 16 Feb. 2024, inthewash.co.uk/cleaning/lint-free-cloth-faqs/. 

Kiel Trinidad

Ryan Culp, Samuel Dale

DES 40A

Professor Cogdell

Embodied Energy of Optical Fingerprint Scanners

As the world develops so does technology, we see so many products that enhance daily life and security. Among these products, optical fingerprint scanners have become an important asset in enhancing personal and organizational security. As the use of this product becomes more widespread, it is important to take into consideration the environmental impact of these devices. Like any product, optical fingerprint scanners require materials and energy for production and operation, and they also generate waste at the end of their lifecycle. In this paper, I am analyzing the energy consumption of optical fingerprint scanners for every stage. This allows me to understand each process better and the pros and cons of security products.

For starters, optical fingerprint scanners are generally made with the following parts: Plastic, Glass, Light Source (LEDs), CCD detectors, and/or CMOS Image Sensor Camera. Plastic is the most common housing for optical fingerprint scanners and the most commonly used plastic for optical fingerprint scanners is ABS plastic. ABS plastic consists of acrylonitrile, butadiene, and styrene which are emulsified together with different percentages and ratios to create ABS plastic. Acrylonitrile is manufactured through ammoxidating propylene, ammonia, and air. Butadiene is produced as a byproduct of ethylene and alkenes through the steam cracking process. During this process, when it is mixed with steam and heated to around 900 degrees Celsius, butadiene and other unsaturated hydrocarbons are produced. Styrene is produced by the dehydrogenation of ethylbenzene. A chemical reaction from benzene and ethylene is required to produce ethlybenzene which the process is called alkylation. After this first process, steam and ethylbenzene are passed through a catalyst to obtain styrene. Glass comes from the raw materials sand, sodium carbonate, and calcium carbonate which has to be heated up to roughly 1500 degrees Celsius. The reason extra raw materials are added to create glass is to make sand easier to melt and lower the melting point which saves time and energy. During this process, the sand becomes a liquid form of glass which then needs to be formed into a desired shape. In this case, the liquid form of glass is being pressed down by a machine in a mold to ensure efficiency, consistency, and precise shapes. For a light source, the most common part found in optical fingerprint scanners is LEDs. LEDs are semiconductor diodes, meaning they have conductive materials like copper and nonconductive materials like gallium arsenide, gallium phosphide, or gallium arsenide phosphide. Gallium is not mined but is found in minerals like bauxite, coal, germanite, diaspore, and sphalerite. Gallium is produced as a by-product of zinc refining. “The concentrate is leached in a two-stage countercurrent oxygen pressure leaching process. The first stage is performed under high acidity low temperature and oxygen pressure conditions to leach more gallium and germanium” (Science Direct). Arsenic can be found in its native state but in small amounts generally, arsenic is found in other minerals. As stated by the Royal Society of Chemistry, “Most arsenic is produced as a by-product of copper and lead refining. It can be obtained from arsenopyrite by heating, causing the arsenic to sublime and leave behind iron(II) sulfide.” Phosphorus is mined from phosphate rock and can be turned into white or red phosphorus. White phosphorus is manufactured by heating phosphate rock with carbon and silica in a furnace. This turns phosphorus into a vapor which has to be collected underwater. Red phosphorus is made by heating white phosphorus around 250 degrees Celsius in the absence of air. Gallium arsenide and gallium phosphide are compounds that have a 1:1 ratio of gallium and arsenic. Gallium and arsenic or phosphide are put through a process called Vertical Gradient Freeze, during which heat energy is used to melt the materials down which is controlled in a temperature zone. “The gradual cooling of the melt initially in the lower area initiates crystal growth in the crucible as the melt freezes. The heated zone slowly moves upward, which means that the solidification front slowly moves upward as well. The crystallization rate depends on how quickly the temperature zone is moved” (PVA TePla). Once you have obtained this crystal ingot, it is then sliced into semiconductor wafers which are sanded and cleaned. These wafers are then cut even smaller into chips which are then put into LED packages. The package is a casing that holds the chip, wire, and phosphor layer. The phosphor layer absorbs the blue light from the LED chip and emits white light. CCD detectors are made out of silicon wafers. Silicon cannot be found by itself in nature but with other minerals. Silicon is usually found in quartz and gravel. They are heated using fossil fuels as energy to achieve high temperatures in a furnace with some source of carbon in the furnace. Once there is a chemical reaction between carbon, oxygen, and quartz CO gas gas forms. Silicon is then produced into its molten form. To use this silicon for CCD detectors, we need its crystalized form using the Czochralski Process. During this process, silicon is melted to around 1412 degrees Celsius and stabilized. A slight temperature drop is needed to start the crystallization process. If the pulling rate and temperature are not regulated this process will fail. Once the crystals are manufactured, they are sliced into thin flat discs and are cleaned and prepared for semiconductor devices like CCD detectors. Now we have all the components and materials that are needed, they will be transported into factories for the next process.

All components are not manufactured in the same place, country, or continent. Chemical energy is needed to transport the components so that factories can start assembling the product. According to the U.S. Energy Information Administration, 27% of energy consumed in the United States was towards transportation. 52% of total energy consumption was gasoline in 2022, while distillates were 23% and jet fuel was 12%. This means that fossil fuels are the main source of energy used for transportation. 

During the use of this product, the most common type of optical fingerprint scanners are wired with a USB cable. An electrical energy source is needed to power this product. Though electrical energy may seem to be the main source of energy, it is actually a secondary source. The primary source of energy is actually through the burning of fossil fuels and that chemical energy is converted into electrical energy. When the scanner is not being used and plugged into an energy source, it only uses around 30mA which is 0.03 watts of energy. During the times it is scanning a fingerprint, it uses 80mA which is 0.08 watts of energy. The minimum amount of energy it can use is 108 watts per hour while the maximum amount of energy it can use is 288 watts per hour. In a business environment in California, the electricity rate is 23.7 cents per kilowatt meaning the max cost per hour for a common optical fingerprint scanner is 6.9 cents per hour to operate.

Electronic devices do not just go to a regular recycling bin, they are actually separated into E-Waste bins in many businesses. I used to work at Best Buy in the warehouse and when electronics were recycled, we would put them in a big cardboard box. Every time the box would be full, we would call someone to come pick up the box usually in a small semi-truck. Transporting the E-Waste uses chemical energy through combustion to give the vehicle power. The first process is sorting which is typically manually sorted and uses human energy as the source. After the sorting process, each device will go through an examination to find out if it is still functional to be reused. If it is unusable, a machine will start shredding and run through a magnetic field to separate the metals and non-metals. 

Overall, the basic consumer of an optical fingerprint scanner only sees the type of energy to be from where it is plugged into. They may look at how many volts or watts it uses but the production and the gathering for the materials is far greater than that. The creation of this not only uses electrical energy but chemical, mechanical, and thermal energy. But production and the gathering of materials are only the tip of the iceberg, there are many more aspects involving the process from beginning to end. 

Thoughts on Research

During the research process of this project, I did not realize how many processes there are for the raw materials. I would not expect silicon to go through a crystallization process and that process had to be very precise. I also did not know that some materials need to go through a cooling process for a chemical reaction to begin, learning about this process made me realize that some products can be time-consuming. Consumers like myself included also do not look at the transportation factor and how much fossil fuel is being used just for transportation. Reading an article about the United States Energy Information Administration about the Use of Energy for Transportation surprised me with all the statistics. When finding out that the energy consumption in the United States is only 27% while knowing that transportation is such a big factor for products, makes me think about what is the other 73% of the energy consumption in the United States. Learning about the insights about just optical fingerprint scanners makes me think that we consumers do not look at the bigger picture of how a product affects the environment. The knowledge I received by taking this class helped me understand how to view products differently. Buying products now will definitely change my perspective about the world and how much energy we use in everyday products.

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Samuel Dale 

Ryan Culp, Kiel Trinidad 

DES 40A

Professor Cogdell 

Life Cycle Analysis: Optical Fingerprint Scanners

The fingerprint as we know it has been used for centuries as a means of identification since Ancient Babylonia and China. The unique ridges, patterns and other characteristics are unrepeated in every individual making them the perfect tool for identity proof. As technology improved and imaging of these features could be achieved, we engineered fingerprint scanners, retina scanners and other forms of quick and simple identity confirmation. We came to know this in the present day as a biometric signature. Across many different industries, biometric signatures are used to prevent bad actors from gaining access to scientific discoveries, resource management and for a range of governments and other businesses. However, the many processes that result in waste in the accumulation of raw materials, manufacturing and eventual recycling stages contribute significantly to toxic environments and global warming.  For the case of this life cycle assessment we will be focusing on the optical fingerprint scanner as it is the most common and oldest form of biometric identification. The in-depth analysis of the several processes of waste by-products through the manufacturing of optical fingerprint scanners indicates many of the materials used in the manufacturing processes, especially plastic and other mined materials, along with the products planned obsolescence are harmful to the environment and do not break down easily leading to an nonrenewable, unsustainable product.

The importance of studying the environmental impacts of sustainable or unsustainable products and designs is great. Often individuals don’t place significant importance on the longevity or biodegradability of the products they use everyday. The significant energy use to create certain tech products is especially great. From research by the UN and several other agencies on the topic compiled a report on E-waste monitoring, finding that “a record 53.6 million metric tonnes (Mt) of electronic waste was generated worldwide in 2019, up 21 per cent in just five years. (Forti, et. al.)” Despite this, the amount of waste that goes unrecycled is also significant, totalling more than 82.6% of the total amount of waste every year. The materials that could be extracted from a product like the optical finger scanner include several critical raw materials such as heavy metals, chemicals and petroleum. 

The collection of raw materials for the manufacturing of optical fingerprint scanners is vast with numerous steps to collect all the needed parts. The critical components of the product include computer chips known as imaging sensors, ABS (acrylonitrile butadiene styrene) plastic housing, glass, and an LED light paired with a phosphor layer which improves luminous efficiency. For fingerprint scanners either CMOS (Complementary Metal-Oxide-Semiconductor) or CCD (Charged-Coupled device) imaging sensors act as a “camera” that takes the digital image of the fingerprint. Materials used in the scanners include silicone for the silicon wafers that transmit signals (transistors), along with metals such as copper, aluminum or gold which would be used for the circuits that transfer these signals throughout the chip. To develop the silicon wafers, factories emit carbon dioxide and sulfur dioxide in the process which are also known as HAPs (Hazardous Air Pollutants) and VOCs (Volatile Organic Compounds) (“Emission Control”). The silica for ultra-pure computer chips and other silicone materials is actually typically made from mining quartz or sandstone and refined, processed, and sorted by size. Silica is typically mined first using traditional heavy machinery then sent through crushing and washing. Washing the material takes a significant amount of water which is another waste and needs wastewater treatment. Rotary dryers then rotate the sand until all the moisture has dissipated. Mining procedures to obtain silica are typically through open-pit mining and underground mining. These mining techniques can be especially harmful to the environment because of significant dust generated (Adams). Inhaling silica dust can lead to lung cancer and other serious ailments. As well, the doping process which removes impurities also uses boron, arsenic and phosphorus. This can lead to health problems for workers using the material and acid burns (LaDou). The mining of copper, aluminum and gold are also known to be taxing on the environment. Copper mining for one makes up the largest amount of metal mining and processing wastes in the United States as it is the most common. This mining is particularly energy intensive and requires many powerful machines. According to the EPA, the “slag” which is excess material produced equals 2.5 million metric tons (MT) of smelter slag and 1.5 million MT of slag tailings per year (“Copper Wastes”). This waste can leach radiable materials into the ground. To separate the rock from the copper, a solvent is used which in turn leads to the waste known as Raffinate. This by-product can be harmful to environmental life but especially aquatic life (“Raffinate Safety Sheet”). All this raw material is then transported to manufacturing facilities which process and develop the optical fingerprint scanners while also disposing of waste. The result of the many processes to extract raw material and use along with transportation to production manufacturing is one of the most notable outputs of waste.

Waste through the production manufacturing of optical fingerprint scanners is complex and concentrates on the waste surrounding the facilities. However, finding information exclusively on the specific assembly processes for the scanners is slim due to the proprietary nature of the information by companies. By focusing on the general components we can get a detailed picture of the general assembly. ABS plastic is one of the main manufactured components and is used in the production of the fingerprint scanners housing, the element that binds the whole product. ABS plastic is a terpolymer meaning it contains a multitude of polymers that act in conjunction to positively impact its properties such as its hardness or durability (“Intro to ABS”). ABS plastic is especially harmful to the environment because it is non biodegradable and recycling it is difficult and energy intensive. (“Recycled ABS”) LED lights are another crucial component to optical fingerprint scanners as they illuminate the finger for the digital image to be taken accurately. LED lights typically have a couple main components; the LED chip, LED package and LED lamp (“LED Manufacturing”). The semiconductor chip, conductible materials for the chip, and phosphor layer would be part of the LED chip. The LED package is the ABS plastic housing for the chip. The LED lamp is the small lightbulb used to illuminate the blue and white light emitted and also tint the color. Most of these materials are similar to that of the entire scanner itself, showing the complexity of all the materials used in the final product. Petroleum, chemicals, etching or trimmings of all raw materials, plastic etc. all are used as solvents, fuel or excess spare material to be recycled. Petroleum is one of the most important factors as it is used as a base in almost all of the products mentioned. As well, the use of machinery that harvests and develops the secondary raw materials and transportation throughout this stage is used resulting in greenhouse gas emissions (GHG). From a study done on GHG emissions from plastic manufacturing done by the University of Beijing showed “in 2007-2017, the GHG emissions of PS, PVC, and ABS in the whole life cycle were 230.34, 677.43, 143.12 Tg CO2e respectively” (Chu. et. al) with 143.12 being for ABS. Chemicals used in the grinding, cleaning and polishing processes also contribute to the wastes of the product and in turn the shavings themselves. These chemicals include acids, solvents and bases such as silica slurries, surfactants or anti-static agents. Finally, etching waste or simply excess waste is cut or dismantled from chips, plastic or metals which accumulate and must be disposed of. After the use of the many manufactured processing of the components that make up optical fingerprint scanners along with copious amounts of waste and pollution, the scanner is then shipped worldwide. 

To expand upon emissions that come from the transportation of the final product to industries around the world as well as throughout the process is another example of its unsustainability. Popular companies for buying optical fingerprint scanners are 3M, Synaptics Incorporated and Anvis Global Inc.. These companies primarily ship their products to consumer electronics companies, military and defense and other government/non-profits. These companies that purchase the products also may ship them out for e-waste. The transportation methods used vary by plane, commercial truck, and train. These methods of transportation, while the only viable options, contribute to pollution. Once shipped from facilities, these products can usually last decades due to the use of the extensive manufacturing and raw materials extraction processes emitting pollution and harmful by-products and waste. 

Optical fingerprint scanners in use don’t give off any significant amounts of waste as they don’t require much upkeep. Generally, waste products include continuous energy used to power the product and cleaning products as well as glass needing repair/replacement. Energy used in the United States for example is primarily fossil fuels like coal, gas and petroleum. The waste from these fossil fuel plants is immense, according to the National Energy and Technology Laboratory “... (fossil fuel plants) generate large quantities of solid residues, principally ash, slag and desulfurization/sulfur by products. (They produce) produced 70-100 million tons of coal utilization byproducts (CUBs) annually in the United States (“Solid Waste”).” Waste also comes in the form of cleaning products used such as canned air and lint free cloths. The scanner may also break down in its components over time with the glass being most prone to breakage. A scratch or stain on the surface of the glass can lead to unclear images being taken of fingerprints. The product is then usually transported to e-waste processing facilities or simply thrown away. While the overall impact of the use of the fingerprint scanner pales in comparison from other processes in the manufacturing, there is still some harmful waste which contributes to the eventual end of life cycle of the product in e-waste. 

E-waste processing facilities usually take electronic products and convert them into usable raw materials but if not recycled are usually thrown away which can leave long lasting impacts on the environment. According to AzoMaterials “The Global E-waste Monitor revealed that of the 53.6 million metric tons of e-waste generated in 2019, only 17.4% was officially documented as properly collected and recycled. (“E-waste”). In the case of optical fingerprint scanners, some of the materials are recyclable. For example, heavy metals like copper can be extracted as well as some silicon properties. The case of optical fingerprint scanners although uses non biodegradable materials such as the ABS plastic and it can be difficult to obtain the raw materials from silicone chips and LED lights. ABS plastic as discussed earlier is a terpolymer meaning it consists of multiple types of polymers as well as additives. The plastic is also often burned at the end of its life cycle as it breaks down at the comparably low 400 degrees Fahrenheit. The air pollution resulting from this is carcinogenic and contains substances like carbon monoxide and the polymers themselves (“Recycled ABS”). The material is then made into recycled ABS plastic which can then be reused. When the material is not thermally recycled however, it can take hundreds of years to decompose. Copper can also be recycled for spare elements and is an essential trace element for the environment making it more renewable than other sources as it can remain in the environment and doesn’t break down, leaving little harm (“Recycling copper”). Glass is also easily recycled but the process only is able to extract about a ⅓ of the materials (Glass: Material Specific Data). CMOS and CCD chips can be recycled but produce immense amounts of waste (Podmore). LED lights can leach lead and arsenic when they are disposed of in landfills as well. Lead and arsenic contamination have been shown to harm wildlife and humans alike. Wastewater treatment from these facilities is also important as chemicals that are processed in the recycling can be released into water sources. These chemicals are also known as liquid effluents and they are processed through several steps of decontamination and filtration before the waste is released into the ocean (Netter). Overall, while some materials from optical fingerprint scanners are recyclable, much of it requires extensive amounts of energy, cannot be fully extracted and are not typically recycled in the first place. 

In summation, the effectiveness of optical fingerprinting is clear but the frightening amount of waste produced is cause for clear concern. Despite this, optical fingerprint scanners are effective and biometric identification is needed for particular industries. During COVID-19, their manufacturing was labeled as an essential component therefore being able to bypass certain safety guidelines. Growth in the industry is valued and projected to be “ at USD 643.8 million in 2019. The market size will reach USD 1025.9 million by the end of 2026. (“Sensor Market”). A more sustainable approach to this product is needed. This could come in the form of using different solvents that are organic and easily biodegradable such as citrus cleansers. Other waste minimization and energy efficiency tactics are also important immediate components that could be set in place. Notably, this is all by design as planned obsolescence creates the opportunity for more advanced products and the life cycle continues. Moreover, switching back to identification using plain ink and paper is also an option as current software could effectively analyze fingerprints without the need for the optical fingerprint scanners. 

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