March 13, 2014
Starbucks Breakfast Blend K-Cup Materials
The journey of a Starbucks Breakfast Blend K-Cup, from raw materials to end product, recycling, and disposal, is one that is expansive and complex. Each component of the K-Cup has its own unique lifecycle which needed to be analyzed in order to create a comprehensive lifecycle analysis for the final product, starting with the planting and extraction of raw materials. In order to acquire the raw materials needed to produce the Starbucks Breakfast Blend K-Cup, the following materials are required.
Coffee tree seeds, soil, water and fossil fuels: trees are planted from seeds and then treated as they germinate and grow. This process requires soil, water and fossil fuels (originating from power plants to provide electricity for regulating water temperature; and to also power farming equipment.) When the trees reach maturity, which typically takes about five years (YouTube), coffee cherries containing the raw beans are picked by hand and sorted for processing/extraction.
After being harvested, the coffee beans need to be extracted and processed. The same raw materials used for acquisition are used for manufacturing, processing, and formulation of the coffee grounds in Starbucks K-Cups, with the exception of coffee tree seeds and soil.
The extraction process is either done via a dry method, where the cherries are dried on the trees or laid out on the ground before the beans are removed by hulling, or a wet method, where the beans are immediately separated using a deep pulper machine. If the wet method is used, coffee cherries and water are put into a depulper machine which is either hand-operated, or powered by diesel fuel.
After being extracted, the coffee beans are put into fermentation tanks, which may or may not contain water, and are then dried using mechanical dryers, which use electricity and/or fossil fuels. The coffee beans are then put in burlap sacks and prepared for delivery to roasting plants (YouTube). When at the roasting plant, the coffee beans are roasted in machines, which rely on electricity (fossil fuels) and natural gases. Once roasted, the coffee is normally packaged and sent off for distribution. In this case, it is assumed that the roasted coffee beans are sent to a Keurig Green Mountain, Inc. facility to grind them and then pack the grounds into K-Cups.
The transportation of coffee beans to a roasting plant relies on fossil fuels, and it is assumed that they’re used to fuel freighters traveling from tropical regions (where the coffee is grown, harvested, etc...) to the US harbors, and then to fuel trucks which take the beans to the roasting centers.
The K-Cup itself is made of three main parts: a plastic container, a paper filter, and an aluminum seal (Wilder). The following materials are used in the acquisition of raw materials needed to create each of the three parts.
Most plastics begin as crude oil/fossil fuels (WiseGeek), and in the case of the K-Cup, crude oil and corn. The K-Cup is categorized as a #7 (mixed) plastic, containing 19% polylactic acid (PLA), which is derived from corn (Green Mountain Coffee Roasters, Inc. 41), (National Research Council (US). The crude oil is extracted from the earth via oil rig drilling.
*Note, this paper assumes the presence of an existing oil rig and does not address the materials involved in the discovery of oil, nor the construction/establishment of an oil rig. The oil rig is powered by generators powered by large engines, which themselves require diesel fuel (Freudenrich, Strickland).
Once the crude oil has been extracted, it needs to be refined into petroleum in order to then be made into plastic. This is done at an oil refinery via fractional or chemical distillation. In fractional distillation, a crude oil mixture is piped into a boiler, exposing it to intense heat, so that it may evaporate in a distillation chamber. In this chamber, various components of the crude oil are cooled as they rise, and are collected in trays as they move up the chamber, condensing into liquid. At this point, the petroleum gas is further condensed and then distilled and chemically processed to purify and obtain the hydrocarbon monomers used in the production of plastics (Freudenrich) (WiseGeek).
Corn and petroleum contain hydrocarbons which are used in the creation of plastics via a process called "cracking", in which they are chemically treated or heated to very high temperatures to break them down into monomers. In the case of corn, it is wet milled to break down into starches and sugars which are then fermented, yielding lactic acid, which is used as a monomer in the production of PLA. In order for corn to be turned into PLA, it must first be planted, grown and harvested. This assumes the presence of typical agricultural chemicals (e.g. fertilizers, pesticides, herbicides, etc...), soil, water, and fossil fuels (used directly to power equipment and indirectly via conversion to electricity) (Environmental Impact).
In both cases, these monomers are then extracted and chemically treated to form long polymer chains. The chains are formed using one of two methods: polymerization (where a chemical is added to the monomers, causing them to combine with each other, forming a resin) or polycondensation (where the monomers are processed and a byproduct is released). Both processes involve the addition various monomers and chemicals), and yield resins of varying strengths, which are then sent to a plastics manufacturer (WiseGeek) and are presumably shipped to one of Keurig Green Mountain, Inc.’s manufacturing facilities to be molded into the K-Cup shape.
The K-Cup’s internal coffee filter is made of paper, which in this case is derived from trees. Assuming the trees are already planted, the first step is to harvest them; a process in which they are cut down, transported to a local area onsite, stripped of branches, and then reduced them to logs. It is assumed that gasoline and diesel is the primary raw material/fuel used for this process. At this stage, the logs are transported to paper mills to be processed further (Smith).
To manufacture the paper coffee filter, the raw wood needs to be reduced to a pulp comprised of cellulose and mostly devoid of lignin and other tree materials. The Kraft pulping process is assumed because it yields paper of adequate strength and durability needed in filter paper (the other mainstream method of pulping is mechanical, and yields paper mostly used for newsprint and packing material) (The Straight Dope). In this pulping process, wood and chemicals are cooked in a pressurized reaction vessel, where most of the undesired materials are “digested”. When the mixture is done cooking, it is shot into a tank, where it disintegrates into pulp upon impact (EPA). It is assumed that no bleaching takes place because the filter is hidden, and because some standard coffee filters are indeed unbleached. The pulp is then put into a paper machine where water is added to create a paste. This paste is then drained, formed into sheets, dried, and wound onto reels for storage. It is assumed that at this stage, the paper is sent to a Keurig Green Mountain, Inc. manufacturing facility to be turned into a K-Cup filter.
The aluminum top to the K-Cup begins as bauxite ore, which is a solid mixture of aluminum oxide, iron oxide, and water molecules. This ore is mined (diesel is again assumed to fuel the equipment), transported (fueled by diesel fuel/gasoline) to washing or crushing plants (powered by fossil fuels/electricity), washed and crushed (water is assumed), and then stockpiled (Harris). Once the bauxite has been separated, it undergoes further processes to transform it into aluminum. (Bauxite Mining)
To transform bauxite ore into aluminum, the aluminum oxide and the iron oxide present need to be separated. This is done via the Bayer process, in which the ore is mixed with a caustic soda and then heated and pressurized. The aluminum oxide is dissolved into liquid, and the iron oxide is filtered out. The addition of aluminum hydroxide produces solid aluminum oxide crystals, which are then washed and heated to remove water, resulting in pure aluminum oxide powder. The powder must then undergo a smelting process, in which it is mixed with molten cryolite and placed in a conductive iron and graphite vat. Carbon and electrical current is then introduced to the vat so that electrolysis (yielding aluminum metal from aluminum ions) may occur. The aluminum metal then sinks to the bottom of the vat and is collected (Harris). At this stage, the aluminum metal is poured into molds, creating ingots, which are then sold to foundries for alloying (mixing with other metals), fluxing (cleaning and purifying with nitrogen or argon gases), and finally, rolling (to create the aluminum foil) (Harris). It is assumed that at this stage, the aluminum is sent to a Keurig Green Mountain, Inc. manufacturing facility (presumably via shipping freighter from Australia, where most bauxite is mined) to be turned into a K-Cup lid, where it will be coated with polyethylene, and printed/branded with the Starbucks Breakfast Blend design.
Once each individual piece is assembled and has arrived at the final manufacturing destination, the Starbucks Breakfast Blend K-Cup is ready to be assembled. It is assumed that the process and machinery used at Keurig Green Mountain, Inc. is very similar to those used in Pack Line East’s KXM-6 K-Cup Packaging Machine. First, all the ingredients and parts (stacks of empty K-Cups, spools of filter paper, coffee grounds and aluminum foil labels) are placed into a packaging machine. The cups are then vacuum suctioned into compartments, where they are held in place. Next, the filter paper is stamped/cut into circular shapes and placed into cups, where they are filled with coffee grounds. The labels are then machine-stamped and heat sealed onto the K-Cups. It is assumed the the nitrogen flushing occurs during this step as well. The K-Cups are now assembled and ready for distribution and transportation.
To “use” a Starbucks Breakfast Blend K-Cup, one of many K-Cup brewing systems is needed, along with a cup to serve the coffee in. K-Cups are intended to be single use servings, and as such, re-use is not recommended by Keurig, and maintenance is not applicable. However, from a waste management perspective, one can purchase a reusable filter system, but this of course deviates from the pre-assembled Starbucks Breakfast Blend K-Cup. Currently, K-Cups as a whole are not recyclable (Keurig), however, two of the three parts (the foil lid and the filter). Water is needed to rinse the remaining coffee grounds from the inner filter. (Home Guides)
For waste management and reduction, Keurig implements a program called “Grounds to Grow On” which is only offered to business and commercial customers in the United States. This program is used “to collect used K-Cup® packs and return them to [their] disposal partner for composting and energy-from-waste processing…” (Keurig) K-Cup recovery bins and labels are needed for this process. When the bins have been filled, the company ships them to Keurig’s disposal partner, where they are ground, separated, and processed for compost, energy, and other applications.
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Breakfast Blend K-Cup Embodied Energy
Since its introduction in 1998 the Keurig K-Cup has been a growing sensation. Patented and owned by Green Mountain Coffee Growers the K-Cup is a self-contained brewing system for coffee, designed specifically for Keurig Single Cup Coffee Brewers. Keurig Brewers and the K-Cup revolutionized the coffee brewing experience. The K-Cup makes getting your morning fix speedier, and more convenient using revolutionary K-Cup technology. The small cylindrical K-Cup is comprised of four main components. (Figures 1 and 2) The outer shell is made of smooth plastic and is designed to protect the coffee grounds inside of the cup. By preventing air and moisture from penetrating the contents of the cup this outer layer ensures freshness with every brew. The inside of the cup contains a small paper filter that is connected to the edges of the cup. Inside the filter sits the coffee grounds, our focus specifically on K-Cups filled with Starbucks Breakfast Blend. The entire container is covered and sealed by an aluminum foil lid sporting the recognizable Starbuck’s logo. (Figure 2) What is now recognize as a K-Cup went through an extreme set of transformations. These tiny cups undergo numerous production processes, and utilize large amounts of energy and other materials before the consumer is able to convert them into his or her morning cup of Joe.
The life cycle of any product starts long before it reaches the consumer; the first stage of any product’s life begins with the primary raw materials that serve as the basis of its fabrication. In order to determine what these primary raw materials were our group investigated what was used to make the materials we had already identified in the K-Cup. The K-Cup is made of #7 plastics; comprised of 19% PLA and 81% Other Plastics. You can tell what type of plastic an item is made of by determining the category, indicated by a number embossed on the product. The #7 category is a catch all for polycarbonate and “other” plastics that could be any combination of different types of polymers. The raw materials typically used to make these types of plastics are fossil products such as crude oils and natural gases. PLA is Polylactic Acid, a synthetic #7 thermoplastic made from any fermentable sugar. Corn is the most commonly used raw material for PLA production. However, the majority of the plastic in the K-Cup is various “other” plastics.
The next major secondary material is the coffee filter inside the cup. My group found that the coffee filter was made of paper; paper being made of wood. The wood used for coffee filters is generally softwood, or wood from a conifer tree. Coffee Beans are the primary raw material used to make the coffee grounds that rest in the coffee filter. The world’s main source of aluminum is Bauxite Ore, and we can assume the aluminum for the K-Cup was extracted from this ore.
After determining what raw materials were used, I went about finding how one might acquire these materials for mass production. The raw materials could generally be acquired in one of two ways, by farming and harvesting or by extraction. Both approaches require copious amounts of energy to get the job done. Farming requires land preparation, planting, tending, and harvesting. All of these procedures require energy from human labor, water, the sun, and fossil fuels. Use of farming equipment is necessary for land cultivation, distribution of pesticides and fertilizers, installing irrigation systems and many other fundamental processes of farming. Materials that cannot be farmed must be excavated from natural supplies in the Earth. Excavation also requires the use of energy from humans, and fossil fuels. Construction equipment like excavators and drills are required for the collection of these kinds of materials and large amounts of fossil fuels are needed to power these machines. Although they use similar types of energies the method of acquisition for each material is unique.
Corn for making PLA, depending on the type, can have a growing time ranging from 55 to 95 days from planting to harvest. Corn harvesting is done using a corn combine machine, which strips all the corn from the cobs and leaves. Next the combine dumps all the kernels into a dump truck where they are shipped off to a location to be made into plastic.
Trees for paper production come from forests called managed timberlands. From planting to harvest a tree forest can take 10-20 years to fully mature; during this time the forest serves as an ecosystem sheltering plants and animals. In preparation of harvest loggers mark trees to show which trees to leave. Next the trees are felled, or cut down, using chainsaws and other types of special equipment. The trees are then pulled to an open area in the harvest location. Depending on tree size, site condition and various other factors the trees can be relocated using bulldozers, and sometimes even helicopters. Next trees are delimbed and cut into smaller sections called logs. The logs are then strapped and loaded onto trucks that will transport them to paper making facilities.
From the time the seeds of coffee trees are planed it takes about 5 years for a tree to produce a harvestable crop; the average tree yields about 1 pound of roasted beans per year. Starbucks picks and sorts coffee cherries for processing by hand. Farmers remove the coffee beans from the cherries via washed or the more “natural” dry method. Using the wet method beans are immediately separated using a deep pulper machine; they are then transported to fermentation tanks where they are dried using mechanical dryers. The dry method allows for the beans to dry on the trees or ground before they are removed by hulling. After the beans have been dried they are loaded by hand into burlap sacks in preparation for their delivery to a roasting plant where it will be roasted for flavor and grinded into coffee grounds then packaged and shipped again to a different processing facility.
The first stage of mining for Bauxite Ore is the preparing the mining area; Bauxite is located in the Earth’s crust and is usually covered by several meters of rock, clay and vegetation, which must all be removed before the bauxite can be collected. The next stage is the actual mining; the ore is removed from the ground using construction extractors. After being extracted Bauxite is shipped to plants where the material is washed and crushed. After the Bauxite is crushed it is ready to be shipped to an aluminum processing facility. Since Australia produces most of the world’s Bauxite it is likely that the fossil product must be loaded onto ships and travel across an ocean before it can be turned into aluminum. Finally the extraction site is rehabilitated; when the ore is washed clay is rinsed off and deposited into tailing ponds which are replanted using local species to re-establish natural vegetation. Crude Oils and Natural Gases undergo similar excavation procedures but are extracted with the use of drills. Once all of these primary raw materials have been collected they are ready to be transported to the next stage in the production process and be fashioned into secondary materials.
The processes used to convert these raw materials into secondary materials utilize a lot chemical energy through the use of intentional chemical reactions. Thermal energy and mechanical energy play as catalysts for these reactions. Plastic, is the most abundant secondary material in the K-Cup. The specific procedures for manufacturing plastic depend on what kind it is. For 81% percent of plastic in the cup coming from unspecified polymers we were unable to get an exact manufacturing process. In general however, the same basic steps are taken to produce all plastics. Plastic is made using a variety of chemical and refining processes that transform single molecules, known as monomers, into long chains called polymers, which are then formed into your desired final product. #7 plastics are often produced from fossil products such as crude oil and natural gas. These contain compounds called hydrocarbons that are either heated to extreme temperatures or chemically treated to break them down into monomers. Once the monomers are extracted they are chemically treated by polymerization or polycondensation to make them bond together to form long polymer chains. PLA begins with the fermentation of corn to produce lactic acid. Once the lactic acid has formed it is condensed into Lactide and then polymerized into PLA. PLA is then reformed into a transportable reformed PLA where it is then shipped and can be reformed again into a final design.
Paper for the coffee filters is made from the cellulose fibers in wood. First, lignin, a polymer in plants that gives them their rigid woody quality and other organic compounds must be separated from the cellulose in a process called pulping. This can be done either mechanically or chemically. Once the wood pulp is isolated it is highly diluted with water and sprayed onto a moving mesh screen in layers to make a mat. The mat is then dehydrated and dried with the use of heated rollers that squeeze the remaining moisture out and compress it into thin strips of paper. Coffee filters are made of crêped in particular because this feature allows coffee to flow freely between the filter and filtration funnel. This crêped texture is created when a blade is used to scrape the paper off the dryer; this causes the paper to wrinkle. The paper is then formed into a coffee filter using a heated press.
Bauxite Ore contains aluminum ore in combination with other minerals. Bauxite is turned into pure aluminum using the Bayer Process. This involves adding sodium hydroxide to the ore which dissolves the oxides of aluminum and silicon; all other impurities are insoluble and can be filtered out. Carbon Dioxide gas is bubbled through the silicon and aluminum oxides which causes the aluminum oxide to precipitate or form a solid. The silicon is then filtered from the solution. The purified aluminum oxide is then heated to evaporate water; once the water has evaporated the aluminum can now be pressed into thin sheets of aluminum foil.
Once the secondary materials have been fabricated through various chemical reactions they are ready to be manufactured into a marketable product. This manufacturing process is largely mechanical, performed by machines running on electricity, but it also utilizes thermal energy. The cylindrical plastic container is thermoformed. PLA and other plastics are heated and combined, then poured into molds heated to 105F; after approximately 2 seconds of heating the molds are cooled, forming rigid containers. The aluminum lids are first printed with the logo for the cup. The same presses and plates used for printing on paper and plastic films are used for printing on foil. Next individual lids are cut from the sheets of aluminum using an aluminum lid punching machine. The different components of the K-Cup can be assembled into one with the use of a filling and sealing machine. These machines are capable of producing upwards of 320 K-Cups per minute. The machine uses an auger filler to insert the coffee grounds; it also provides a simultaneous nitrogen injection into the container to ensure freshness. The machine inserts and holds the filter steady while the cup is being filled. Finally the machine seals the package with pre-cut aluminum foil lidding using heat. Machines are also used to pack the K-Cups into cartons which are then palletized and readied for shipping. The cups are shipped to retailers like grocery stores where they will then be purchased and used to brew coffee.
Using the K-Cup is enormously simple, which is what has made this such a successful product. To brew a single cup of coffee you simply insert the K-Cup into a special compartment in your Keurig Brewer; when you close the compartment it is punctured with a tiny skewer that allows coffee to be brewed by flowing through the container. You press a button and your Keurig Brewer takes care of the rest. The K-Cup is meant for one time use; after brewing the cup can simply be recycled or thrown away.
Only two elements of the K-Cup are recyclable; the lid can be pulled off and placed with aluminum recyclables and the filter can be recycled with paper products. Recycling aluminum requires melting and reformation using heat and mechanical machinery. Recycling paper involves re-pulping using water and chemicals; the new pulp is then reformed into paper. Although the lid and filter may be recycled the main component of the K-Cup, the plastic container, must be disposed of in a landfill. Haulers must transport K-Cup trash to landfills where the trash is then buried which require extensive use of energy in construction vehicles and human labor.
Although the K-Cup is small, standing at a measly 1.75” in height, it has a complex life cycle we don’t always recognize. The amount of energy and resources that go into creating one K-Cup is extensive when you take all processes into consideration. Massive amounts of electricity go into powering the machines that manufacture these products, in addition to the energy required from fossil fuels and humans. Although the K-Cup is revolutionary in function, it is not revolutionary in the way of sustainable design. I learned there is a significant use of non-renewable energy and materials that go into producing this design. To address this problem Green Mountain Coffee Growers has created a reusable K-Cup that can be loaded with your own coffee grounds and cleaned after use. However this solution slightly defeats the convenience of having a Keurig Brewer. The company is in the processes of manufacturing a K-Cup with a container made entirely of PLA so it is completely recyclable. But until then it seems the K-Cups may continue to contribute to our landfills.
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13 March 2014
Waste and Emissions from the K-Cup
As the ever-popular Keurig machine is making its way into more homes and offices every day, its convenience of disposable k-cups is leading to expanding environmental consequences of high waste and emissions from the start to finish of its life-cycle. Nearly every single-serving k-cup that is used is thrown away - heading straight for the landfill to sit on a plot of land for an indefinite amount of time. It could potentially be taken apart to recycle certain parts, but it is such a difficult task that not many will do so for monetary gain or for the re-use of a few little scraps. The small k-cup comes in four major components consisting of the plastic cup, a paper filter, an aluminum lid, and of course the coffee grounds. The lifecycle of the k-cup requires a multitude of raw materials that require extensive energy through processing as well as transportation, which lead to growing wastes and emissions, causing the k-cup to not be a sustainable product.
The start of the lifecycle requires the acquisition of a range of raw materials through different methods. The main primary materials needed are coffee beans, corn, crude oil, natural gas, bauxite ore, petroleum, and pulp from wood, fibre crops or waste paper. The planting and harvesting of the coffee beans from coffee cherries and corn require a vast amount of water which leads to waste water because of sediment run-off of loose soil washed off fields, which is the biggest proponent of agricultural waste products (“Polluted”). According the EPA, non-point source pollution (NPS) comes from many diffuse sources through water run-off which picks up and carries away natural and human-made pollutants, and leaving them little by little in bodies of water like river, lakes, coastal waters, and underground sources of drinking water (“Polluted”). In the water and solid mixture waste of washed sediment usually includes some amount of pesticides as well, which are a cause of water pollution. Some pesticides are persistent organic pollutants (POPs) that are resistant to environmental degradation to a varying degree of biological and chemical processes and contribute to soil contamination; POPs can include the following compounds: PCBs (polychlorinated biphenyl), DDT (dichlorodiphenyltrichloroethane), HCHs (hexachlorocyclohexane), and chlordanes (Ritter). Air-borne wastes that come in hand with agriculture include CO2 (carbon dioxide) emissions from fossil fuels used to power farming equipment and for regulating water temperature, as well as N2O (nitrous oxide) from soil when nitrogen is added in for synthetic fertilizer. Solid wastes of the coffee cherries include the the cherry pulp, and solid wastes up to about 17% of the corn is wasted in regard to the corn stalks and ears that are unused (“Biofuel”).
Mining drills and other large mining machines in order to obtain bauxite ore, run primarily on diesel oil, which release diesel exhaust particles (DEP) into the atmosphere from the 40 chemical components, including Group 1, 2, and 3 carcinogens (“Diesel”). These particle components include diesel soot and aerosols, like ash particles, metallic abrasion particles, sulfates and silicates. According to the Health Assessment Document For Diesel Engine Exhaust by the EPA, these particles are also ultrafine particles (UFPs or PM0.1) which are exceptionally small and in the invisible range of 100 nanometers; this makes them difficult to regulate and measure, which is dangerous because they are a major concern for respiratory health due to exposure. Aldehydes are one of the main gaseous emissions and include formaldehyde, which “makes up the majority of the aldehyde emissions (65% to 80%), with acetaldehyde being the second most abundant aldehyde in HD diesel emissions (“Health”).
The mined bauxite ore is then used through the Bayer process to become aluminum, which is abundant, but not found in its final state in nature. The Bayer process (refer to Fig 2) used to refine bauxite into aluminum oxide to be then refined into aluminum metal consists of crushing, milling, pressuring, filtering and cooling. In the process of aluminum hydroxide decomposing into aluminium oxide, water vapor is released. Solids from the filtering process leave“red mud” which consists of solid and metallic oxide-bearing impurities which is large waste problem as it cannot be disposed of easily. It is usually pumped into holding ponds and takes up land area which becomes useless. The muds is highly basic (10 to 13 pH) and impacts the environment, however, a few methods have been developed to lower the alkaline pH to an acceptable level so it is not too harmful or toxic in itself to the environment; however, the copious amounts that are forced to build up on land sites are becoming an issue (Schmitz). The mud is red from oxidised iron, consisting up to 60% of the waste; other particles include silica, titanium oxide, and unleached residual aluminum (Babel). The left-over NaOH solution used in the pressure vessel as a hot wash to digest the bauxite in order for it to become soluble is recycled. The recycling process produces gallium and vanadium impurities and build-up which are eventually extracted (Babel).
The process of preparing coffee beans into roasted and ground coffee discharges water waste as well and is one of the biggest waste products from making the k-cups. The coffee water waste is not uniform as there are varying amounts of contaminants but they are not necessarily dangerous in themselves; “problems occur through large amounts of effluents disposed into watercourses heavily loaded with organic matter rather its than inherent toxicity” (Adams). The processing of coffee cherries in batches requires two parts: de-pulping and fermentation alongside washing. This leads to organic matter set free when the mesocarp, the middle layer of the coffee cherry, is pulped and removed; the pulping water consists of quickly fermenting sugars, proteins, and pectins (water-soluble colloidal carbohydrates found in ripe fruits) from the components (Adams). The machines used to de-pulp are either hand-operated or powered by diesel fuel, which mainly emits aldehydes and formaldehyde.
Water waste from coffee production sits at an acidity of below pH of four and BOD (Biological Oxygen Demand), which indicates the amount of oxygen needed to break down organic matter, of up to 20,000 mg/l from remains of pulp, and up to up to 8,000 mg/l from fermentation; these are both extremely high numbers as the BOD “should be reduced to less than 200 mg/l before let into natural waterways” or is other words, safe to be exposed (Enden).
The solid wastes in the COD can be removed through precipitation of the water as mucilage solids, and other solids found in minute amounts are toxic, such as tannins, alkaloids (caffeine) and polyphenolics, but are usually maintained in the disposed solids of the coffee pulp. Other characteristics of water waste that were sampled in Nicaragua found that the total nitrogen (TN) concentration ranged from 50 to 110 mg/l, average 90 mg/l and total phosphorus (TP) concentration ranged from 8.9 to 15.2 mg/l, average 12.4 mg/l. COD averages are also rising from 5,400 mg/l up to 8,400 mg/l after pulp removal (Grendelman). These numbers are at maximum COD loads, reflecting maximum water pollution. For every 625 tonnes of ripe coffee cherries processed, there are 25 tonnes of pulp waste and 25,000 liters containing 1,250 kg of COD and 375 kg of BOD (Enden).
The fermentation of the sugars (from the pectin after the coffee is pulped) into ethanol and carbon dioxide leads to acid conditions in the washing water. The ethanol is converted in acetic acids after reaction with oxygen; this lowers the pH to about four, which can negatively affect the treatment efficiency of facilities treating the coffee wastewater and is considered to be detrimental for aquatic life when released into surface waters (Treagust).
The machinery used to manufacture corn into PLA (polylactic acid) plastic in addition with Number 7 plastic is unclear and sparse. The process is known, but without complete information about the energy and machines used, it is difficult to access the waste and emissions. The PLA plastic is made from fermentation of sugar from corn and makes up 19% of the k-cup. The chemical and refining processes turn single monomers made from crude oil and natural gases containing hydrocarbons into chains forming polymers are then reformed into a final product by polymerization or polycondensation. Number 7 plastic is a category for “other” plastics, and these plastics are not meant for re-use and are non-recyclable which lead to more waste. PLA plastics emit about 1820 kg/ton of carbon dioxide, which is less than a quarter of emissions compared cellophane and less by half of nylon emissions (refer to Fig 2). Figure 3 shows that PLA uses 762 MJ /1000 cups of fossil resources and that these figures differ compared to PLA and polystyrene in various waste disposal systems such as incineration, composting, and anaerobic digestion. These figures show that carbon dioxide is emitted, but in relatively small amounts compared to other types of plastics; however, the same source that provided the figures also states that “CO2 is a raw material, not a waste product” because PLA “uses it successfully as a raw material because the fermentation and chemical processing technologies are very efficient and have high yields” (National). Overall, PLA production must produce carbon dioxide, but it does so at generally low emissions.
The pulp from wood, fibre crops or waste paper to make the paper filters in the k-cups use a digester machine which cooks wood and chemicals to dissolve lignin in order to free cellulose fibers. The machine emits solid wastes called black liquor and is usually incinerated at paper mills as an energy source (“How”). In fact, solid wastes like black liquor, waste pulp, bark, wood scraps, and leaves and needles are needed to make many mills generate electricity; because of this, the paper mill industry is considered a major “green power” producer as 46-55% of energy is self-produced with biomass waste (“How”).
Transportation of the raw materials to specific industries specialized in production processes are hard to trace, because there are many sources of raw materials and private factories. Bauxite ore, however, is primarily found in Australia and must be transported by cargo vessels. Most of these are powered by heavy fuel oil also known as bunker fuel, which is much worse for the environment than diesel fuel. International standards are becoming more strict to reduce sulphur content and nitrogen oxide emissions and have been pushing to use clean diesel or marine gas oil instead (Assessment). Other transportation involving trucks are required to move raw materials to producers, producers to stores, stores to homes, and finally homes to disposal systems that often lead to massive landfills. PLA has a hopeful future, however, as it “degrades quickly in environments of high temperature, high moisture, and high microbial activity” but is also stable when used in normal conditions. These unique characteristics “may allow accelerated development of alternative waste disposal systems, such as composting and anaerobic digestion” (National). The two parts of the k-cup including the paper filter and aluminum lid can technically be recycled but once they land in the landfills, they become too difficult to be separated from the other many materials.
All in all, the k-cup seems to be a very simple product but it clearly has many consequences when the materials are processed many times with added chemicals and compounds, emitting high gaseous doses. These processes notably emit run-off sediment causing waste water through pesticide contamination, carbon dioxide emissions, red mud containing solid and metallic oxide-bearing impurities, and many others. The increasingly popular single-use of the product also eliminates potential for wastes and emissions to slow down; targeting efficiency improvement is seemingly the best way to tackle the production of k-cups. The Keurig site says that “finding a more environmentally friendly approach to this packaging challenge is a big priority” but time can only tell what changes will take place, and if they will, or can, take place soon enough (“L.A.”). The lifecycle of the k-cup is clearly extensive and not fully uncovered as of yet, but awareness of wastes and emissions into the water, air, and land that affect our health and the health of the ecosystem and environment is the first step to a cleaner world.
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