Design Life-Cycle

Jason Leung

Professor Cogdell

DES 40A

March 15, 2018

Disposable Chopstick Life Cycle

Chopsticks are an important component of Asian culture since they are the utensil of choice for meals, and the popularity of disposable chopsticks has increased because of to-go restaurants. Today, chopsticks are commonly used around the globe, even though they originated from Asia.  The modernization of chopstick manufacturing is the result of increasing demand for these commonly used utensils; however, the production of disposable chopsticks consequently leads to the waste of raw materials and uses potentially harmful chemicals. The lifecycle of disposable chopsticks from its creation to commercial distribution starts at the harvest of raw materials, resulting in a devastating impact on the surrounding environment by processes such as deforestation. By understanding the processes behind harvesting the raw materials used in the production of disposable chopsticks, we will have a better understanding of what steps are needed to limit harmful effects of large-scale manufacturing on the environment.

The production of disposable chopsticks begins with the destruction of forests to harvest timber. Disposable chopsticks are primarily composed of aspen wood, but other organic materials such as bamboo, oak, and cedar are commonly used in the production of chopsticks. The woods used must have certain properties such as hardness and imperviousness to water in order to be used for chopstick composition. However, this process causes severe deforestation, as the 50 billion chopsticks produced from China cut down over 20 million trees. A mixture of heavy machinery and chainsaws are used to both cut down the trees and load the timber onto trucks to have the wood transported to a mill to be processed. The machinery require lots of fuel in the form of gasoline to power the chainsaw and the heavy machinery. For trees on level ground, diesel-powered tractors are used to transport the fallen trees onto trucks for loading. Other machinery, like telescoping hydraulic yarders, are used for steep slopes in order to effectively collect the most amount of trees. If the trees are on level ground, the wood is dragged directly to the loading trucks. In contrast, if the trees grow on uneven ground, the wood is raised in the air and guided by guide wires to the loading trucks. The fuels necessary to power the machines are extracted from crude oil fracked from oil-rich locations such as Middle East and then processed into gasoline or diesel fuel to power the vehicles and tools necessary to cut down the trees.

The wood is then transported to sawmills where they are milled, steamed, and cut into the familiar chopstick shape. The milling of wood consists of cutting the logs into small blocks to prepare for steaming so the wood will be easier to peel into long boards in later parts of the manufacturing process. Cutting and shaping the wood involves using a bandsaw, usually with a carbon steel blade. The carbon steel blade consists of material primarily comprised of iron and copper, but also has trace amounts of other elements such as chromium, cobalt, nickel and titanium. These elements are smelted in blast furnaces to expel any impurities and input carbon to create a strong blade that will cut through wood with ease. The blocks of wood are steamed in a steam box, made of material that range from treated wood to PVC pipes. Steam boxes made of PVC are really made of vinyl chloride monomer, a synthetic material created by combining chlorine obtained through electrolysis of salt and ethylene in a reactor at high temperatures. The PVC steam boxes are attached to a steam generator, which uses water pumped through tubes made of alloy 600, a non-corrosive nickel-chromium-iron solid alloy. This alloy is created by combining the elements together at a very high temperature in a furnaces. This results in a product that is capable of withstanding high heat so water can be heated while travelling through the furnace without compromising the structural integrity of the metal itself. The water is heated in the tubes and produces steam that is injected into the steam box containing wooden planks. By steaming the wooden planks, they are making the wood more flexible and easier to peel. They are peeled using a veneer peeling machine equipped with a carbon steel blade, resulting in logs that are cut into thin boards, usually about 5 millimeters thick. These planks of wood are then cut again using a heat stamp that cuts the final shape of the chopsticks.

These chopsticks are then put into a chemical bath, but the process itself remains unknown to the public as the Chinese national standards have no record of this process, and companies withhold the details of this information in their manufacturing. In 2010, the Chinese government imposed limits on chemical usage in chopsticks, but these limits were never strictly enforced. China’s lenient quality inspection has led to many chopstick manufacturing plants to operate with little to no scrutiny for the chemical treatment of its products. Through alternative sources of experiments from other companies and individual investigators, chopsticks have been known to be treated with low levels of sulfur dioxide, hydrogen peroxide, sodium sulfite and mold inhibitors. The U.S FDA restricts sulfur dioxide in fresh food to be 10 parts per million but does not impose that restriction on preserved or non-digestible products. Most of these factories are small workshops in remote areas, safe from any prying eyes and investigation by authorities. This reduces the restriction placed on these factories due to the lack of an effective quality control department to oversee production. Non-restrictive practices such as this give the chopsticks a yellow tint, indicating that those chopsticks are linked to excessive sulfur mixed into the wood. Based on reports done at small-scale chopstick factories, we assume this chemical treatment occurs after the wood has been cut into the final shape. There is a report depicting a large chemical bath, assumingly sulfur dioxide based on the description of a yellow liquid, with bundles of finished chopsticks being soaked in this bath. Sulfur dioxide is a waste product from processes such as burning fossil fuels and smelting mineral ores, where is is then captured and used as an aqueous solution to treat the wood. This process requires a metallic sulfide, which comes from hard rock mining of metals in sulfide ores. The sulfide ores are extracted from mines in the form of minerals such as copper sulfide, iron sulfide, and silver sulfide and then smelted in factories to burn off the sulfur to purify the desired mineral. Instead of letting the sulfur dissipate into the air and cause harmful toxic effects, the gas is captured and liquefied by using ice and salts as well as a high pressure to create an aqueous sulfur dioxide solution.

These finished chopsticks are then shipped out on cargo ships running mainly on heavy fuel oil. These tanker ships are some of the largest air polluters, using the lowest grade oil that contain the most amount of sulfur, causing enough pollution equivalent to the emissions of 50 million cars. They use crude oil that is hardly refined, often waste oil after other fuels like diesel and heating fuels are created. The chopsticks then are offloaded onto heavy and medium duty trucks, using diesel or regular fuel to transport the chopsticks to the desired location. Most of these chopsticks are used once then disposed of when most wooden disposable chopsticks are compostable and can go in a green bins. The end of the lifecycle of disposable chopstick usually landfill, as very few chopsticks are reused in any way but new innovative and creative ways are currently being devised in order to minimize the waste created by chopsticks. In few instances, people use creative methods to build sculptures and artwork to raise awareness of the environmental impact disposable chopsticks have on forests. However, there are new ideas to reduce waste by using wasted chopsticks to create biofuels. Companies are experimenting by using potassium carbonate to liquidate the chopsticks into a bio-oil with characteristics similar to diesel while being more efficient to heavy oil. These ideas however result in severe pollution like carbon dioxide and nitrous oxide, so scientists are continuing to work on a way to utilize chopsticks effectively while minimizing the pollutants released from it.

The lifecycle of the chopstick is one that is severely wasteful, and the environment is paying the price, as well as possibly our health. Chopsticks use around 4 million trees each year in China alone with the majority of them ending up in a landfill since they are rarely recycled. Due to the leniency of health and safety policies of these rural chopstick factories, we don’t know the quantity or type of chemicals used to coat these chopsticks; instead, we rely on individual investigators to deduce the composition of the chemical baths used. However, there is starting to be a shift in people carrying their own personal reusable pair of chopsticks, usually made of metal, bamboo or plastic. This change is a gradual one, and there are still over 50 billion chopsticks produced each year in China, resulting in not only the waste from creating the product, but also from using fuels to transport them all around the world via plane, boat and trucks. 

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Erica Lee

DES 40A

Winter 2018

Disposable wooden chopsticks, a staple utensil at Asian restaurants, are often tossed in the trash without second thought. These seemingly harmless wooden sticks, treated with multiple chemicals and thus making them not biodegradable, take up a great deal of space in landfills. These disposable wooden chopsticks generate tons of waste in the duration of their life cycle, from their inception, to their transportation, and to the end of their lives. Although alternative methods to reuse wooden chopsticks have been devised, they still produce wastes and it will be a while before these methods are implemented on a larger scale.

Right from the start, during the acquisition of raw materials for disposable wooden chopsticks, millions of trees are cut, which increases overall carbon dioxide levels in the atmosphere. Cutting down trees for wooden chopsticks and their paper wrappers have been accelerating the deforestation of Chinese forests — forests which are crucial for absorbing carbon dioxide (Nuwer). Trees are necessary to reduce the amount of carbon dioxide in the atmosphere. Although the acquisition process of raw materials for wooden chopsticks isn’t necessarily adding wastes to the environment, but the diminishing number of trees result in a reduction of natural resources that lower the concentration of carbon dioxide in the air. On average, a mature tree can absorb forty-eight pounds of carbon dioxide per year and roughly 16 million to 25 million trees are felled a year for wooden chopsticks (American Forests; Gardner). Given the statistics, about 768 million to 1.2 billion pounds of carbon dioxide emissions are prevented from being absorbed.

Manufacturing disposable wooden chopsticks is a multiple step process, and with that multiple step process comes multiple different types of waste. Generally, mass produced wooden chopsticks follow the same steps: first the wood is milled which cuts it into blocks, then the blocks are cut, sanded, finished with chemicals, and then wrapped in their paper wrappers. One upside of the process is the reusable byproduct of the milled and shaved wood. However, the machinery used to shape the wood require diesel and gasoline which emits carbon dioxide gas. In 2008, China’s Timbers, Wood, Bamboo, Rattan, Palm, and Straw products manufacturing subsector produced over twenty-five megatons of carbon dioxide emissions (Lu and Price). In addition to the carbon dioxide emissions from the machinery used, the chemical processing of the wooden chopsticks produces hazardous chemical waste. Generally, the wooden chopsticks are bathed in a solution of different chemical compounds, but the most common ingredient used is sulfur dioxide (Nuwer). Sulfur dioxide, is a hazardous material and needs to be disposed after proper neutralization methods. Many of the companies that manufacture disposable chopsticks, do not undergo the proper disposal methods which contaminate water and soil quality. Even if the sulfur dioxide is properly neutralized with sodium carbonate, the products of that reaction result in sodium hydrosulfite, which can be reused as a reducing agent, and carbon dioxide gas, which are more greenhouse gases going into the atmosphere. The last step of the manufacturing process is the wrapping of these wooden chopsticks. Although there isn’t much research on the wrappers, it is safe to say that there is waste from chemical processes from manufacturing the paper wrappers. Once wrapped, the paper chopsticks are ready to be transported.

Transportation of disposable wooden chopsticks from factory to restaurants around and across the Pacific has its economic benefits, but the thousands of miles traveled has its effect on the environment. Chinese made disposable chopsticks are both consumed in China and exported to Japan, Korea, and the United States (Nuwer). They’re shipped overseas on cargo boats use heavy fuel and then are driven to their final destinations in heavy trucks that consume diesel or unleaded gas. The main pollutants from the cargo ships are exhaust gas which include sulfur oxides and nitrous oxides (International Maritime Organization). The diesel exhaust, considered a group one carcinogen, from trucks contains nitrous oxides, sulfur oxides, hydrocarbons, aldehydes, and more (National Toxicology Program). Once these chopsticks arrive at their destinations, they are unpackaged from their boxes and taken out of the plastic wrapper that hold anywhere from forty to one hundred pairs of chopsticks. Immediately the plastic film wrappers are thrown in the trash. Depending on their resin types, they can be recycled, but most of the time, they cannot be recycled, adding plastic waste into landfills (American Chemistry Council). Then the cardboard boxes they arrive in are generally recycled, reused, or thrown into the trash where they will eventually decompose. Arguably, the transportation of the chopsticks produces the largest amount of waste in the whole life cycle of a pair of disposable chopsticks due to the sheer millions of tons of exhaust from cargo ships and trucks.

Once used, disposable wooden chopsticks are thrown away and into landfills they go. Since wooden chopsticks are bleached and treated with the chemical bath, they are not compostable. When people throw away the wooden chopsticks, they end up in landfills and eventually these wooden chopsticks will biodegrade over a few decades. The larger issue is that fact that China goes through roughly forty-five billion pairs of disposable wooden chopsticks a year while the international market goes through over eighteen billion pairs of the wooden chopsticks and over ninety percent of these wooden chopsticks end up in landfills around the world (Gardner). Furthermore, disposable wooden chopsticks are accountable for the destruction of over a million square meters of Chinese forests every year (Dewey). The reality is, because of the chemicals used for these disposable wooden chopsticks, there aren’t many options for recycling or reusing these chopsticks. As the chopsticks are considered disposable, washing and reusing the wooden chopsticks can be hazardous to human health as the sulfur dioxide chemical solution that the chopsticks were treated in can get into food. The treatment of the chopsticks makes it a challenge to recycle them. Consequently, landfills end up with mountains of disposable wooden chopsticks.

In recent years, there have been pushes to reduce the number of chopsticks going into landfills. Alternate disposal methods and recycling methods for wooden chopsticks have been devised. Recently, a few Chinese university students realized that they could use disposable bamboo chopsticks to make carbon fibers that could be used to create sustainable anodes for Lithium-ion batteries (Jiang et al.). This would reduce the number of disposable chopsticks going to landfills and also reduce the amount of commercial graphite being produced, reducing wastes from the manufacturing sector as well. Another alternative disposal method that was being discussed was converting bamboo chopsticks to bio-oil (Chiang et al.). This method would reduce the quantity of disposable wooden chopsticks being sent to landfills but would produce different types of waste. The process of changing biomass to bio-oil using potassium carbonate as a catalyst for liquefaction would result in a bio-oil with characteristics close to diesel while being superior to heavy oil and boat oil (Chiang et al.). However, bio-oil use, or the combustion of bio-oil still produces exhaust. Although the exhaust levels are lower, due to the increased content of nitrogen in the bio-oil, there are more nitrous oxides being emitted into the atmosphere (Kowalewski 30). As bio-oil combusts, there will be chemical reactions that produce carbon dioxide emissions. The idea that disposable wooden chopsticks can be recycled is an idea that many experiment with, however, with each new method tested, there are wastes produced as a consequence of the testing.

As much waste as these wooden chopsticks produce, disposable chopsticks won’t go away anytime soon. Over 100,000 people are employed in factories that produce wooden chopsticks (Gardner). The chopsticks industry is creating jobs for the uneducated poor people who live around China’s forests. Additionally, the cost of these disposable wooden chopsticks makes them so desirable to restaurant owners and consumers alike. While a pair of disposable chopsticks go for less than a cent, their reusable counterparts can cost up to $1.17 and reusable chopsticks need sterilization after each use which can range from 15 to 70 cents (Nuwer; Gardner). In recent years, however, China has been making moves to try to save their forests by placing a five percent tax on disposable chopsticks. Although this change isn’t the most impactful, this has led way for other Asian countries to push for reusable chopsticks and continues to raise awareness about the impacts of disposable wooden chopsticks.

Up until 2006, people have used and thrown away disposable wooden chopsticks carelessly. There wasn’t any reason to suspect that every year, millions of square meters of forests were being wiped out. Consumers didn’t think that the pair of disposable chopsticks they used for their Asian food came with a side of millions of tons carbon dioxide and nitrous oxide emissions or that the utensil was dipped in a chemical bath of sulfur dioxide. The disposable chopstick industry created hills of chopsticks in landfills while trees that were millions of years old were being cut down. Although there has been research in how to reuse chopsticks, it’s not enough to stop the deforestation. Trees are considered a renewable source of energy, but when the rate of consumption is faster than the rate of renewability, it fosters an unsustainable economy. In order to reduce wastes, disposable wooden chopsticks industry needs to be permanently disposed.

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